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Banayan Esfahani E, Asadi Zeidabadi F, Jafarikojour M, Mohseni M. Photo-reductive decomposition of perfluorooctane sulfonate (PFOS) and its common alternatives by UV/VUV/sulfite process: Mechanism, kinetic modeling, and water matrix effects. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 951:175796. [PMID: 39187080 DOI: 10.1016/j.scitotenv.2024.175796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2024] [Revised: 08/22/2024] [Accepted: 08/23/2024] [Indexed: 08/28/2024]
Abstract
The present study investigated the photo-reduction of perfluorooctane sulfonate (PFOS) and its alternatives, focusing on decomposition mechanisms, active species involvement, the influence of background water constituents, and kinetic model development. The decomposition and defluorination rates followed the order of PFOS > PFHxS > 6:2 FTSA > PFBS, with shorter chains and CH2 linkers enhancing the resistance of PFOS alternatives against the attack of hydrated electrons (eaq-). Two primary pathways were identified during the photodegradation of PFAS: (i) H/F exchange at CF bonds with the lowest bond dissociation energies (BDEs) and (ii) functional group cleavage followed by short-chain PFCAs formation, with OH playing a crucial role in transforming intermediates. Adding iodide and elevated temperatures demonstrated a synergistic effect on PFBS decomposition and defluorination, with high temperatures promoting functional group cleavage as the preferred defluorination pathway. The study examined the impact of background water constituents in different aqueous environments, from surface waters to wastewater streams and ion-exchange brine concentrates. Chloride exhibited a concentration-based dual impact on the UV/VUV/sulfite process: promotive effects at low dosages (1-10 mM) by acting as a secondary eaq- mediator, and adverse effects at high dosages (20-500 mM) due to the scavenging effect of generated chlorine radicals (Cl). High ionic strength adversely affected eaq- quantum efficiency. Additionally, bicarbonate and natural organic matter (NOM) had opposing effects on PFOS photo-reduction, primarily through eaq- scavenging and pH alteration. Kinetic modeling revealed reaction rate constants of the studied PFAS with eaq- ranging from 1.8 × 106 to 1.3 × 109 M-1 s-1, corroborating the concentration profiles of active species and highlighting the reductive nature of sulfite-mediated processes.
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Affiliation(s)
- Ehsan Banayan Esfahani
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, Canada
| | - Fatemeh Asadi Zeidabadi
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, Canada
| | - Morteza Jafarikojour
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, Canada
| | - Madjid Mohseni
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, Canada.
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Zeng Y, Dai Y, Yin L, Huang J, Hoffmann MR. Rethinking alternatives to fluorinated pops in aqueous environment and corresponding destructive treatment strategies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174200. [PMID: 38936705 DOI: 10.1016/j.scitotenv.2024.174200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 05/25/2024] [Accepted: 06/20/2024] [Indexed: 06/29/2024]
Abstract
Alternatives are being developed to replace fluorinated persistent organic pollutants (POPs) listed in the Stockholm Convention, bypass environmental regulations, and overcome environmental risks. However, the extensive usage of fluorinated POPs alternatives has revealed potential risks such as high exposure levels, long-range transport properties, and physiological toxicity. Therefore, it is imperative to rethink the alternatives and their treatment technologies. This review aims to consider the existing destructive technologies for completely eliminating fluorinated POPs alternatives from the earth based on the updated classification and risks overview. Herein, the types of common alternatives were renewed and categorized, and their risks to the environment and organisms were concluded. The efficiency, effectiveness, energy utilization, sustainability, and cost of various degradation technologies in the treatment of fluorinated POPs alternatives were reviewed and evaluated. Meanwhile, the reaction mechanisms of different fluorinated POPs alternatives are systematically generalized, and the correlation between the structure of alternatives and the degradation characteristics was discussed, providing mechanistic insights for their removal from the environment. Overall, the review supplies a theoretical foundation and reference for the control and treatment of fluorinated POPs alternatives pollution.
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Affiliation(s)
- Yuxin Zeng
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
| | - Yunrong Dai
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, PR China.
| | - Lifeng Yin
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
| | - Jun Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control (SKJLESPC), Beijing Key Laboratory for Emerging Organic Contaminants Control (BKLEOC), School of Environment, POPs Research Center, Tsinghua University, Beijing 100084, PR China.
| | - Michael R Hoffmann
- Department of Environmental Science & Engineering, California Institute of Technology, Pasadena, CA 91125, United States.
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3
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Wu H, Wang J, Du E, Guo H. Comparative analysis of UV-initiated ARPs for degradation of the emerging substitute of perfluorinated compounds: Does defluorination mean the sole factor? JOURNAL OF HAZARDOUS MATERIALS 2024; 474:134687. [PMID: 38805816 DOI: 10.1016/j.jhazmat.2024.134687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/25/2024] [Accepted: 05/20/2024] [Indexed: 05/30/2024]
Abstract
Due to the increasing attention for the residual of per- and polyfluorinated compounds in environmental water, Sodium p-Perfluorous Nonenoxybenzenesulfonate (OBS) have been considered as an alternative solution for perfluorooctane sulfonic acid (PFOS). However, recent detections of elevated OBS concentrations in oil fields and Frontal polymerization foams have raised environmental concerns leading to the decontamination exploration for this compound. In this study, three advanced reduction processes including UV-Sulfate (UV-SF), UV-Iodide (UV-KI) and UV-Nitrilotriacetic acid (UV-NTA) were selected to evaluate the removal for OBS. Results revealed that hydrated electrons (eaq-) dominated the degradation and defluorination of OBS. Remarkably, the UV-KI exhibited the highest removal rate (0.005 s-1) and defluorination efficiency (35 %) along with the highest concentration of eaq- (K = -4.651). Despite that nucleophilic attack from eaq- on sp2 carbon and H/F exchange were discovered as the general mechanism, high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC/Q-TOF-MS) analysis with density functional theory (DFT) calculations revealed the diversified products and routes. Intermediates with lowest fluorine content for UV-KI were identified, the presence nitrogen-containing intermediates were revealed in the UV-NTA. Notably, the nitrogen-containing intermediates displayed the enhanced toxicity, and the iodine poly-fluorinated intermediates could be a potential-threat compared to the superior defluorination performance for UV-KI.
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Affiliation(s)
- Han Wu
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Jingquan Wang
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Erdeng Du
- School of Environmental and Safety Engineering, Changzhou University, Changzhou 213164, China
| | - Hongguang Guo
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
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Awoyemi OS, Luo Y, Niu J, Naidu R, Fang C. Ultrasonic degradation of per-and polyfluoroalkyl substances (PFAS), aqueous film-forming foam (AFFF) and foam fractionate (FF). CHEMOSPHERE 2024; 360:142420. [PMID: 38795914 DOI: 10.1016/j.chemosphere.2024.142420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/20/2024] [Accepted: 05/22/2024] [Indexed: 05/28/2024]
Abstract
The ubiquitousness of per- and polyfluoroalkyl substances (PFAS) is a big concern and PFAS remediation is urgently needed such as via degradation. While previous studies have explored ultrasonic degradation of PFAS, work evaluating the operational parameters is rare, especially concerning real wastes such as aqueous film-forming foam (AFFF) and foam fractionate (FF). This study investigates the key operational parameters affecting the degradation efficiency of PFAS, encompassing ultrasonication frequency (580-1144 kHz), power intensity (125-187.5 W), initial concentration (0.08-40 ppm), treatment duration (0.5-3 h), sample volume (100-500 mL), and PFAS structure (perfluorooctanoic acid or PFOA; perfluorooctane sulfonate or PFOS; 6:2 fluorotelomer sulfonate or 6:2 FTS). The defluorination kinetics is different from the removal/degradation kinetics due to the generation of degradation intermediates, suggesting the complex degradation mechanism, which should be evaluated to close the mass balance effectively. Notably, the optimised ultrasonic system achieves ∼125%/∼115% defluorination in AFFF/FF example wastes (compared to ∼65%/∼97% removal) despite their complex composition and the involvement of total oxidizable precursor (TOP) assay. In the meantime, a few new PFAS are detected in the post-treatments, including perfluorohexane sulfonic acid (PFHxS) and 10:2 fluorotelomer sulfonate (10:2 FTS) in the AFFF, and perfluorooctane sulfonamide (FOSA) and 8:2 fluorotelomer sulfonate (8:2 FTS) in the FF, again suggesting the complex degradation mechanism. Overall, ultrasonication is effective to degrade PFAS real example wastes, advancing its potential for scale-up applications.
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Affiliation(s)
- Olalekan Simon Awoyemi
- Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW, 2308, Australia; CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Yunlong Luo
- Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Junfeng Niu
- College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China
| | - Ravi Naidu
- Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW, 2308, Australia; CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Cheng Fang
- Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW, 2308, Australia; CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), University of Newcastle, Callaghan, NSW, 2308, Australia.
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Zhai Z, Zhang C, Chu L, Zhao Y, Zhou X, Zhang Y. Effective defluorination of novel hexafluoropropylene oxide oligomer acids under mild conditions by UV/sulfite/iodide: mechanisms and ecotoxicity. WATER RESEARCH 2024; 258:121804. [PMID: 38781621 DOI: 10.1016/j.watres.2024.121804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 04/08/2024] [Accepted: 05/18/2024] [Indexed: 05/25/2024]
Abstract
It has recently been discovered that HFPO-TA (a processing aid in the production of fluoropolymers) has high levels of bioaccumulation and biotoxicity. Hydrated electrons (eaq-) have been proposed to be potent nucleophiles that may decompose PFAS. Unlike previous studies in which the generation of eaq- was often restricted to anaerobic or highly alkaline environments, in this study, we applied the UV/SO32-/I- process under mild conditions of neutrality, low source chemical demand, and open-air, which achieved effective degradation (81.92 %, 0.834 h-1) and defluorination (48.99 %, 0.312 h-1) of HFPO-TA. With I- as the primary source of eaq-, SO32- acting as an I- regenerator and oxidizing substances scavenger, UV/SO32-/I- outperformed others under mild circumstances. The eaq- were identified as the main active species by quenching experiments and electron paramagnetic resonance (EPR). During degradation, the first site attacked by eaq- was the ether bond (C6-O7), followed by the generation of HFPO-DA, TFA, acetic and formic acid. Degradation studies of other HFPOs have shown that the defluorination of HFPOs was accompanied by a clear chain-length correlation. At last, toxicological experiments confirmed the safety of the process. This study updated our understanding of the degradation of newly PFASs and the application of eaq- mediated photoreductive approaches under mild conditions.
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Affiliation(s)
- Zhenyu Zhai
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Chaojie Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
| | - Liquan Chu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Yunmeng Zhao
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Xuefei Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Yalei Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
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6
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Trzcinski AP, Harada KH. Comparison of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutane sulfonate (PFBS) removal in a combined adsorption and electrochemical oxidation process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172184. [PMID: 38575007 DOI: 10.1016/j.scitotenv.2024.172184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/08/2024] [Accepted: 04/01/2024] [Indexed: 04/06/2024]
Abstract
This study focused on three of the most studied PFAS molecules, namely perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutane sulfonate (PFBS). They were compared in terms of their adsorption capacity onto graphite intercalated compound (GIC), a low surface area, highly conductive and cheap adsorbent. The adsorption on GIC followed a pseudo second order kinetics and the maximum adsorption capacity using Langmuir was 53.9 μg/g for PFOS, 22.3 μg/g for PFOA and 0.985 μg/g for PFBS due to electrostatic attraction and hydrophobic interactions. GIC was added into an electrochemical oxidation reactor and >100 μg/L PFOS was found to be fully degraded (<10 ng/L) leaving degradation by-products such as PFHpS, PFHxS, PFPeS, PFBS, PFOA, PFHxA and PFBA below 100 ng/L after 5 cycles of adsorption onto GIC for 20 min followed by regeneration at 28 mA/cm2 for 10 min. PFBS was completely removed due to degradation by aqueous electrons on GIC flakes. Up to 98 % PFOA was removed by the process after 3 cycles of adsorption onto GIC for 20 min followed by regeneration at 25 mA/cm2 for 10 min. When PFBS was spiked individually, only 17 % was removed due to poor adsorption on GIC. There was a drop of 3-40 % by treating PFOS, PFOA and smaller sulfonates in a real water matrix under the same electrochemical conditions (20 mA/cm2), but PFOS and PFOA removal percentage were 95 and 68 % after 20 min at 20 mA/cm2.
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Affiliation(s)
- Antoine P Trzcinski
- School of Agriculture and Environmental Science, University of Southern Queensland, West Street, 4350, Queensland, Australia.
| | - Kouji H Harada
- Department of health and environmental sciences, Graduate school of Medicine, Kyoto University, Kyoto 606-8501, Japan
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7
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Jiang Z, Denisov S, Adjei D, Mostafavi M, Ma J. Overlooked Activation Role of Sulfite in Accelerating Hydrated Electron Treatment of Perfluorosulfonates. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:9427-9435. [PMID: 38747404 DOI: 10.1021/acs.est.4c01444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Photoexcitation of sulfite (SO32-) is often used to generate hydrated electrons (eaq-) in processes to degrade perfluoroalkyl and polyfluoroalkyl substances (PFASs). Conventional consensus discourages the utilization of SO32- concentrations exceeding 10 mM for effective defluorination. This has hindered our understanding of SO32- chemistry beyond its electron photogeneration properties. In contrast, the radiation-chemical study presented here, directly producing eaq- through water radiolysis, suggests that SO32- plays a previously overlooked activation role in the defluorination. Quantitative 60Co gamma irradiation experiments indicate that the increased SO32- concentration from 0.1 to 1 M enhances the defluorination rate by a remarkable 15-fold, especially for short-chain perfluoroalkyl sulfonate (PFSA). Furthermore, during the treatment of long-chain PFSA (C8F17-SO3-) with a higher concentration of SO32-, the intermediates of C8H17-SO3- and C3F7-COO- were observed, which are absent without SO32-. These observations highlight that a higher concentration of SO32- facilitates both reaction pathways: chain shortening and H/F exchange. Pulse radiolysis measurements show that elevated SO32- concentrations accelerate the bimolecular reaction between eaq- and PFSA by 2 orders of magnitude. 19F NMR measurements and theoretical simulations reveal the noncovalent interactions between SO32- and F atoms, which exceptionally reduce the C-F bond dissociation energy by nearly 40%. As a result, our study offers a more effective strategy for degrading highly persistent PFSA contaminants.
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Affiliation(s)
- Zhiwen Jiang
- School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
- Institute de Chimie Physique, UMR8000 CNRS/Université Paris-Saclay, Orsay 91405, France
| | - Sergey Denisov
- Institute de Chimie Physique, UMR8000 CNRS/Université Paris-Saclay, Orsay 91405, France
| | - Daniel Adjei
- Institute de Chimie Physique, UMR8000 CNRS/Université Paris-Saclay, Orsay 91405, France
| | - Mehran Mostafavi
- Institute de Chimie Physique, UMR8000 CNRS/Université Paris-Saclay, Orsay 91405, France
| | - Jun Ma
- School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
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Chen Y, Zhu J, Ma H, Gu Y, Liu T. Fe 2+-NTA synergized UV 254 photolytic defluorination of perfluorooctane sulfonate (PFOS): Enhancing through intramolecular electron density perturbation via electron acquisition. WATER RESEARCH 2024; 254:121421. [PMID: 38461601 DOI: 10.1016/j.watres.2024.121421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/27/2024] [Accepted: 03/04/2024] [Indexed: 03/12/2024]
Abstract
Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant posing a risk in environmental persistence, bioaccumulation and biotoxicity. This study was to reach a comprehensive and deeper understanding of PFOS elimination in a UV254 photolytic treatment with the co-presence of Fe2+ and nitrilotriacetic acid trisodium salt (NTA). PFOS defluorination was noticeably enhanced in the UV/Fe2+-NTA treatment compared with UV/NTA, UV/Fe2+ and our previously studied UV/Fe3+ treatments. UV-vis, FTIR, and UPLC/MS-MS results indicated the formation of PFOS-Fe2+-NTA complex in PFOS, Fe2+ and NTA mixture. The transition energy gap of PFOS-Fe2+-NTA decreased below the excitation energy supplied by UV254 irradiation, corresponding with red shift appearing in UV-vis scanning spectrum. This favored intramolecular electron transfer from Fe2+-NTA to PFOS under UV254 irradiation to form electron-accepting PFOS. Molecular electrostatic potential and atom charge distribution analyses suggested electron density rearrangement and perturbation in the perfluorinated carbon chain of electron-accepting PFOS, leading to the decrease in bond dissociation energies. Intermediate products detection suggested the parallel defluorination pathways of PFOS desulfonation, middle carbon chain scission and direct C-F cleavage. NTA exhibited crucial functions in the UV/Fe2+-NTA treatment by holding Fe2+/Fe3+ in soluble form as a chelant and favoring water activation to generate hydrated electrons (eaq-) under UV irradiation as a photosensitizer. Fe2+ acting as the conduit for electron transfer and the bridge of PFOS anion and NTA was thought functioning best at 200 µM in this study. The degree of UV/Fe2+-NTA -synergized PFOS defluorination also depended on eaq- yield and UV254 photon flux. The structure dependence on the electron transfer process of PFOS and PFOA was explored incorporating molecular structure descriptors. Because of possessing greater potential to acquire electrons or less likeliness to donate its electrons than PFOA, PFOS exhibited faster defluorination kinetics in the published "reduction treatments" than "oxidation" ones. Whereas, PFOA defluorination kinetics were at similar level in both "reduction" and "oxidation" treatments.
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Affiliation(s)
- Yihua Chen
- Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Jiaxin Zhu
- Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Hang Ma
- Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Yurong Gu
- Shenzhen Polytechnic University, Shenzhen 518055, China
| | - Tongzhou Liu
- Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
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Londhe K, Lee CS, Grdanovska S, Smolinski R, Hamdan N, McDonough C, Cooper C, Venkatesan AK. Application of electron beam technology to decompose per- and polyfluoroalkyl substances in water. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 348:123770. [PMID: 38493862 DOI: 10.1016/j.envpol.2024.123770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/04/2024] [Accepted: 03/10/2024] [Indexed: 03/19/2024]
Abstract
The widespread detection of per- and polyfluoroalkyl substances (PFAS) in environmental compartments across the globe has raised several health concerns. Destructive technologies that aim to transform these recalcitrant PFAS into less toxic, more manageable products, are gaining impetus to address this problem. In this study, a 9 MeV electron beam accelerator was utilized to treat a suite of PFAS (perfluoroalkyl carboxylates: PFCAs, perfluoroalkyl sulfonates, and 6:2 fluorotelomer sulfonate: FTS) at environmentally relevant levels in water under different operating and water quality conditions. Although perfluorooctanoic acid and perfluorooctane sulfonic acid showed >90% degradation at <500 kGy dose at optimized conditions, a fluoride mass balance revealed that complete defluorination occurred only at/or near 1000 kGy. Non-target and suspect screening revealed additional degradation pathways differing from previously reported mechanisms. Treatment of PFAS mixtures in deionized water and groundwater matrices showed that FTS was preferentially degraded (∼90%), followed by partial degradation of long-chain PFAS (∼15-60%) and a simultaneous increase of short-chain PFAS (up to 20%) with increasing doses. The increase was much higher (up to 3.5X) in groundwaters compared to deionized water due to the presence of PFAS precursors as confirmed by total oxidizable precursor (TOP) assay. TOP assay of e-beam treated samples did not show any increase in PFCAs, confirming that e-beam was effective in also degrading precursors. This study provides an improved understanding of the mechanism of PFAS degradation and revealed that short-chain PFAS are more resistant to defluorination and their levels and regulation in the environment will determine the operating conditions of e-beam and other PFAS treatment technologies.
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Affiliation(s)
- Kaushik Londhe
- Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ, 07102, USA; New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Cheng-Shiuan Lee
- Research Center for Environmental Changes, Academia Sinica, Taipei, 115, Taiwan
| | | | - Rachel Smolinski
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Noor Hamdan
- Department of Environmental Health and Engineering, Johns Hopkins University, MD, 21205, USA
| | - Carrie McDonough
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Charles Cooper
- Fermi National Accelerator Laboratory, Batavia, IL, 60510, USA
| | - Arjun K Venkatesan
- Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ, 07102, USA; New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY, 11794, USA.
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10
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Amador CK, Vyas S, Strathmann TJ. Kinetic Model for Predicting Perfluoroalkyl Acid Degradation During UV-Sulfite Treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6425-6434. [PMID: 38554136 DOI: 10.1021/acs.est.3c10584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/01/2024]
Abstract
Hydrated electron (eaq-) treatment processes show great potential in remediating recalcitrant water contaminants, including perfluoroalkyl and polyfluoroalkyl substances (PFAS). However, treatment efficacy depends upon many factors relating to source water composition, UV light source characteristics, and contaminant reactivity. Here, we provide critical insights into the complex roles of solution parameters on contaminant abatement through application of a UV-sulfite kinetic model that incorporates first-principles information on eaq- photogeneration and reactivity. The model accurately predicts decay profiles of short-chain perfluoroalkyl acids (PFAAs) during UV-sulfite treatment and facilitates quantitative interpretation of the effects of changing solution composition on PFAS degradation rates. Model results also confirm that the enhanced degradation of PFAAs observed under highly alkaline pH conditions results from changes in speciation of nontarget eaq- scavengers. Reverse application of the model to UV-sulfite data collected for longer chain PFAAs enabled estimation of bimolecular rate constants (k2, M-1 s-1), providing an alternative to laser flash photolysis (LFP) measurements that are not feasible due to the water solubility limitations of these compounds. The proposed model links the disparate means of investigating eaq- processes, namely, UV photolysis and LFP, and provides a framework to estimate UV-sulfite treatment efficacy of PFAS in diverse water sources.
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Affiliation(s)
- Camille K Amador
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Shubham Vyas
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Timothy J Strathmann
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
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11
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Qi Y, Yang Y, Cui S, Tang X, Zhang P, Wang C, Liang Y, Sun H, Ma C, Xing B. Novel Defluorination Pathways of Perfluoroether Compounds (GenX): α-Fe 2O 3 Nanoparticle Layer Retains Higher Concentrations of Effective Hydrated Electrons. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:5567-5577. [PMID: 38488517 DOI: 10.1021/acs.est.3c09879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
The development of efficient defluorination technology is an important issue because the kind of emerging pollutant of hexafluoropropylene oxide dimer acid (GenX) as an alternative to perfluorooctanoic acid (PFOA) has the higher environmental risks. In the UV/bisulfite system, we first developed a hydrophobic confined α-Fe2O3 nanoparticle layer rich in oxygen vacancies, which accelerated the enrichment of HSO3- and GenX on the surface and pores through electrostatic attraction and hydrophobic interaction, retaining more hydrated electrons (eaq-) and rapidly destroying GenX under UV excitation. Especially, under anaerobic and aerobic conditions, the degradation percentage of GenX obtain nearly 100%, defluorination of GenX to 88 and 57% respectively. It was amazed to find that the three parallel H/F exchange pathways triggered by the rapid reactions of eaq- and GenX, which were unique to anaerobic conditions, improved the efficiency of fluoride removal and weaken the interference of dissolved oxygen and H+. Therefore, this study provided an available material and mechanism for sustainable fluoride removal from wastewater in aerobic and anaerobic conditions.
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Affiliation(s)
- Yuwen Qi
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Yinbo Yang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300354, PR China
| | - Shengyan Cui
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Xuejiao Tang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Peng Zhang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Cuiping Wang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Yanna Liang
- Department of Environmental and Sustainable Engineering, University at Albany, SUNY, Albany, New York 12222, United States
| | - Hongwen Sun
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Chuanxin Ma
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States
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12
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Zhu H, Xia Y, Zhang Y, Kang Y, Ding Y, Chen R, Feng H. Distribution characteristics and transformation mechanism of per- and polyfluoroalkyl substances in drinking water sources: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 916:169566. [PMID: 38160823 DOI: 10.1016/j.scitotenv.2023.169566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 12/03/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024]
Abstract
Per- and polyfluoroalkyl substances (PFASs) have raised significant concerns within the realm of drinking water due to their widespread presence in various water sources. This prevalence poses potential risks to human health, ecosystems, and the safety of drinking water. However, there is currently a lack of comprehensive reviews that systematically categorize the distribution characteristics and transformation mechanisms of PFASs in drinking water sources. This review aims to address this gap by concentrating on the specific sources of PFASs contamination in Chinese drinking water supplies. It seeks to elucidate the migration and transformation processes of PFASs within each source, summarize the distribution patterns of PFASs in surface and subsurface drinking water sources, and analyze how PFASs molecular structure, solubility, and sediment physicochemical parameters influence their presence in both the water phase and sediment. Furthermore, this review assesses two natural pathways for PFASs degradation, namely photolysis and biodegradation. It places particular emphasis on understanding the degradation mechanisms and the factors that affect the breakdown of PFASs by microorganisms. The ultimate goal is to provide valuable insights for the prevention and control of PFAS contamination and the assurance of drinking water quality.
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Affiliation(s)
- Heying Zhu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, Zhejiang, China
| | - Yijing Xia
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, Zhejiang, China
| | - Yifeng Zhang
- Department of Environmental and Resource Engineering, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Ying Kang
- Zhejiang Ecological Environmental Monitoring Center, 117 Xueyuan Road, Hangzhou 310012, Zhejiang, China
| | - Yangcheng Ding
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, Zhejiang, China
| | - Ruya Chen
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, Zhejiang, China.
| | - Huajun Feng
- Ecological-Environment & Health College (EEHC), Zhejiang A & F University, Hangzhou 311300, Zhejiang, China.
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13
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Trzcinski AP, Harada K. Combined adsorption and electrochemical oxidation of perfluorooctanoic acid (PFOA) using graphite intercalated compound. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:19946-19960. [PMID: 38367112 PMCID: PMC10927886 DOI: 10.1007/s11356-024-32449-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 02/08/2024] [Indexed: 02/19/2024]
Abstract
Perfluorooctanoic acid (PFOA) is a bioaccumulative synthetic chemical containing strong C-F bonds and is one of the most common per- and polyfluoroalkyl substances (PFAS) detected in the environment. Graphite intercalated compound (GIC) flakes were used to adsorb and degrade PFOA through electrochemical oxidation. The adsorption followed the Langmuir model with a loading capacity of 2.6 µg PFOA g-1 GIC and a second-order kinetics (3.354 g µg-1 min-1). 99.4% of PFOA was removed by the process with a half-life of 15 min. When PFOA molecules broke down, they released various by-products, such as short-chain perfluoro carboxylic acids like PFHpA, PFHxA, and PFBA. This breakdown indicates the cleavage of the perfluorocarbon chain and the release of CF2 units, suggesting a transformation or degradation of the original compound into these smaller acids. Shorter-chain perfluorinated compounds had slower degradation rates compared to longer-chain ones. Combining these two methods (adsorption and in situ electrochemical oxidation) was found to be advantageous because adsorption can initially concentrate the PFOA molecules, making it easier for the electrochemical process to target and degrade them. The electrochemical process can potentially break down or transform the PFAS compounds into less harmful substances through oxidation or other reactions.
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Affiliation(s)
- Antoine P Trzcinski
- School of Agriculture and Environmental Science, University of Southern Queensland, West Street, Queensland, 4350, Australia.
| | - Kouji Harada
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
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14
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Tan X, Shi Y, Ma CF, Chi Q, Yang YH, Zhang WX, Xiao HM, Wang X. Fluoro-functionalized plant biomass adsorbent: Preparation and application in extraction of trace perfluorinated compounds from environmental water samples. J Environ Sci (China) 2024; 137:703-715. [PMID: 37980053 DOI: 10.1016/j.jes.2023.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/17/2023] [Accepted: 03/17/2023] [Indexed: 11/20/2023]
Abstract
Perfluorinated compounds (PFCs) are toxic and widely present in the environment, and therefore effective adsorbents are required to remove PFCs from environmental water. In the present study, a new type of fluorinated biomass materials was synthesized via an ingenious fluorosilanization reaction. These adsorbents were applied for the adsorption of 13 typical PFCs, including perfluorocarboxylic acids (PFCAs) and perfluorosulfonic acids (PFSAs). By comparing their adsorption performance, Fluorinated cedar slag (FCS) was discovered to have the best absorption efficiency and enabled highly efficient enrichment of PFCs. The adsorption recovery of FCS with the investigated PFCs is greater than 90% under the optimal adsorption condition. Ascribed to the high affinity of F-F sorbent-sorbate interaction, FCS had good adsorption capacities of PFCs from aqueous solution, with the maximum adsorption capacity of 15.80 mg/g for PFOS and 10.71 mg/g for PFOA, respectively. Moreover, the adsorption time could be achieved in a short time (8 min). Using the FCS absorbent, an innovative FCS-solid phase extraction assisted with high performance liquid chromatography-electrospray-tandem mass spectrometry (FCS-SPE-HPLC-ESI-MS/MS) method was first developed to sensitively detect PFCs in the environmental water samples. The intra-day and inter-day recovery rates of the 13 compounds ranged from 90.7%-104.3%, with the RSD of 2.1%-4.7% (intra-day) and 2.5%-8.5% (inter-day), respectively. This research demonstrates the potential of the newly fluoro-functionalized plant biomass to adsorb PFCs from environmental water, with the advantages of high adsorption efficiencies, high anti-interference, easy operation and low economic cost.
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Affiliation(s)
- Xi Tan
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China
| | - Yan Shi
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China
| | - Chun-Feng Ma
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China
| | - Quan Chi
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China
| | - Yu-Hang Yang
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China
| | - Wen-Xiang Zhang
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China
| | - Hua-Ming Xiao
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China; Key Laboratory of Oilseeds Processing of Ministry of Agriculture, Hubei Key Laboratory of Lipid Chemistry and Nutrition, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Xian Wang
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China.
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15
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Antonopoulou M, Spyrou A, Tzamaria A, Efthimiou I, Triantafyllidis V. Current state of knowledge of environmental occurrence, toxic effects, and advanced treatment of PFOS and PFOA. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 913:169332. [PMID: 38123090 DOI: 10.1016/j.scitotenv.2023.169332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 12/11/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are anthropogenic synthetic compounds, with high chemical and thermal stability and a persistent, stable and bioaccumulative nature that renders them a potential hazard for the environment, its organisms, and humans alike. Perfluorooctane sulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA) are the most well-known substances of this category and even though they are phased out from production they are still highly detectable in several environmental matrices. As a result, they have been spread globally in water sources, soil and biota exerting toxic and detrimental effects. Therefore, up and coming technologies, namely advanced oxidation processes (AOPs) and advanced reduction processes (ARPs) are being tested for their implementation in the degradation of these pollutants. Thus, the present review compiles the current knowledge on the occurrence of PFOS and PFOA in the environment, the various toxic effects they have induced in different organisms as well as the ability of AOPs and ARPs to diminish and/or eliminate them from the environment.
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Affiliation(s)
- Maria Antonopoulou
- Department of Sustainable Agriculture, University of Patras, 30131 Agrinio, Greece.
| | - Alexandra Spyrou
- Department of Sustainable Agriculture, University of Patras, 30131 Agrinio, Greece
| | - Anna Tzamaria
- Department of Sustainable Agriculture, University of Patras, 30131 Agrinio, Greece
| | - Ioanna Efthimiou
- Department of Biology, Section of Genetics Cell Biology and Development, University of Patras, 26500 Patras, Greece
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16
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Li Y, Tao C, Fu D, Jafvert CT, Zhu T. Integrating molecular descriptors for enhanced prediction: Shedding light on the potential of pH to model hydrated electron reaction rates for organic compounds. CHEMOSPHERE 2024; 349:140984. [PMID: 38122944 DOI: 10.1016/j.chemosphere.2023.140984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Hydrated electron reaction rate constant (ke-aq) is an important parameter to determine reductive degradation efficiency and to mitigate the ecological risk of organic compounds (OCs). However, OC species morphology and the concentration of hydrated electrons (e-aq) in water vary with pH, complicating OC fate assessment. This study introduced the environmental variable of pH, to develop models for ke-aq for 701 data points using 3 descriptor types: (i) molecular descriptors (MD), (ii) quantum chemical descriptors (QCD), and (iii) the combination of both (MD + QCD). Models were screened using 2 descriptor screening methods (MLR and RF) and 14 machine learning (ML) algorithms. The introduction of QCDs that characterized the electronic structure of OCs greatly improved the performance of models while ensuring the need for fewer descriptors. The optimal model MLR-XGBoost(MD + QCD), which included pH, achieved the most satisfactory prediction: R2tra = 0.988, Q2boot = 0.861, R2test = 0.875 and Q2test = 0.873. The mechanistic interpretation using the SHAP method further revealed that QCDs, polarizability, volume, and pH had a great influence on the reductive degradation of OCs by e-aq. Overall, the electrochemical parameters (QCDs, pH) related to the solvent and solute are of significance and should be considered in any future ML modeling that assesses the fate of OCs in aquatic environment.
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Affiliation(s)
- Yi Li
- School of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, Jiangsu, China
| | - Cuicui Tao
- School of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, Jiangsu, China
| | - Dafang Fu
- School of Civil Engineering, Southeast University, Nanjing, 210096, China
| | - Chad T Jafvert
- Lyles School of Civil Engineering, and Environmental & Ecological Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Tengyi Zhu
- School of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, Jiangsu, China.
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17
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Wang Z, Jin X, Hong R, Wang X, Chen Z, Gao G, He H, Liu J, Gu C. New Indole Derivative Heterogeneous System for the Synergistic Reduction and Oxidation of Various Per-/Polyfluoroalkyl Substances: Insights into the Degradation/Defluorination Mechanism. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21459-21469. [PMID: 38056012 DOI: 10.1021/acs.est.3c05940] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
The hydrated electron (eaq-) system is typically suitable for degrading perfluoroalkyl substances (PFASs). To enhance eaq- utilization, we synthesized a new indole compound (DIHA) that forms stable nanospheres (100-200 nm) in water via a supramolecular assembly. Herein, the DIHA nanoemulsion system exhibits high degradation efficiencies toward a broad category of PFASs, regardless of the headgroup, chain length, and branching structure, under UV (254 nm) irradiation. The strong adsorption of PFAS on the DIHA surface ensures its effective degradation/defluorination. Quenching experiments further demonstrated that the reaction took place on the surface of DIHA nanospheres. This specific heterogeneous surface reaction unveiled novel PFAS degradation and defluorination mechanisms that differ from previously reported eaq- systems. First, the photogenerated surface electrons nonselectively attacked multiple C-F bonds of the -CF2- chain. This plays a dominant degrading/defluorinating role in the DIHA system. Second, abundant hydroxyl radicals (•OH) were also produced, leading to synergistic reduction (by surface electron) and oxidation (by surface •OH) in a single system. This facilitates faster and deeper defluorination of different structured PFASs through multiple pathways. The new mechanism inspires the design of innovative organo-heterogeneous eaq- systems possessing synergistic reduction and oxidation functions, thereby making them potentially effective for treating PFAS-contaminated water.
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Affiliation(s)
- Zhe Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Xin Jin
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
- School of Environment, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Ran Hong
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu 241000, P. R. China
| | - Xinhao Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Zhanghao Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Guandao Gao
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Huan He
- School of Environment, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Jinyong Liu
- Department of Chemical & Environmental Engineering and Materials Science & Engineering Program, University of California, Riverside, California 92521, United States
| | - Cheng Gu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
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18
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Marciesky M, Aga DS, Bradley IM, Aich N, Ng C. Mechanisms and Opportunities for Rational In Silico Design of Enzymes to Degrade Per- and Polyfluoroalkyl Substances (PFAS). J Chem Inf Model 2023; 63:7299-7319. [PMID: 37981739 PMCID: PMC10716909 DOI: 10.1021/acs.jcim.3c01303] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 11/21/2023]
Abstract
Per and polyfluoroalkyl substances (PFAS) present a unique challenge to remediation techniques because their strong carbon-fluorine bonds make them difficult to degrade. This review explores the use of in silico enzymatic design as a potential PFAS degradation technique. The scope of the enzymes included is based on currently known PFAS degradation techniques, including chemical redox systems that have been studied for perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) defluorination, such as those that incorporate hydrated electrons, sulfate, peroxide, and metal catalysts. Bioremediation techniques are also discussed, namely the laccase and horseradish peroxidase systems. The redox potential of known reactants and enzymatic radicals/metal-complexes are then considered and compared to potential enzymes for degrading PFAS. The molecular structure and reaction cycle of prospective enzymes are explored. Current knowledge and techniques of enzyme design, particularly radical-generating enzymes, and application are also discussed. Finally, potential routes for bioengineering enzymes to enable or enhance PFAS remediation are considered as well as the future outlook for computational exploration of enzymatic in situ bioremediation routes for these highly persistent and globally distributed contaminants.
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Affiliation(s)
- Melissa Marciesky
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Diana S Aga
- Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260, United States
| | - Ian M Bradley
- Department of Civil, Structural, and Environmental Engineering, State University of New York at Buffalo, Buffalo, New York 14228, United States
- Research and Education in Energy, Environmental and Water (RENEW) Institute, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Nirupam Aich
- Department of Civil and Environmental Engineering, University of Nebraska─Lincoln, Lincoln, Nebraska 68588-0531, United States
| | - Carla Ng
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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19
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Vatankhah H, Anderson RH, Ghosh R, Willey J, Leeson A. A review of innovative approaches for onsite management of PFAS-impacted investigation derived waste. WATER RESEARCH 2023; 247:120769. [PMID: 37931356 DOI: 10.1016/j.watres.2023.120769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 11/08/2023]
Abstract
The historic use of aqueous film-forming foam (AFFF) has led to widespread detection of per- and polyfluoroalkyl substance (PFAS) in groundwater, soils, sediments, drinking water, wastewater, and receiving aquatic systems throughout the United States (U.S.). Prior to any remediation activities, in order to identify the PFAS-impacted source zones and select the optimum management approach, extensive site investigations need to be conducted. These site investigations have resulted in the generation of considerable amount of investigation-derived waste (IDW) which predominantly consists of well purging water and drill fluid, equipment washing residue, soil, drill cuttings, and residues from the destruction of asphalt and concrete surfaces. IDW is often impacted by varying levels of PFAS which poses a substantial challenge concerning disposal to prevent potential mobilization of PFAS, logistical complexities, and increasing requirement for storage as a result of accumulation of the associated wastes. The distinct features of IDW involve the intermittent generation of waste, substantial volume of waste produced, and the critical demand for onsite management. This article critically focuses on innovative technologies and approaches employed for onsite treatment and management of PFAS-impacted IDW. The overall objective of this study centers on developing and deploying end-of-life treatment technology systems capable of facilitating unrestricted disposal, discharge, and/or IDW reuse on-site, thereby reducing spatial footprints and mobilization time.
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Affiliation(s)
- Hooman Vatankhah
- Strategic Environmental Research and Development Program and the Environmental Security Technology Certification Program, Arlington, VA, USA; Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA; Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, USA.
| | | | | | | | - Andrea Leeson
- Strategic Environmental Research and Development Program and the Environmental Security Technology Certification Program, Arlington, VA, USA
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20
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Hou C, Deng J, Li S, Li H, Zhou Y, Zhai Y. Differences between reductive defluorination of perfluorooctanoic acid by chlorination, bromination, and iodization in the vacuum-ultraviolet/sulfite process. JOURNAL OF HAZARDOUS MATERIALS 2023; 460:132459. [PMID: 37683349 DOI: 10.1016/j.jhazmat.2023.132459] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/25/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023]
Abstract
The introduction of iodide (I-) has broad perspectives on the decomposition of perfluorocarboxylates (PFCAs, CnF2n+1COO-). However, the iodinated substances produced are highly toxic synthetic chemicals, hence, it is urgent to find a similar alternative with less toxicity. In this work, the defluorination of perfluorooctanoic acid (PFOA) by I-, bromide (Br-) and chlorine (Cl-) was systematically compared in the VUV/sulfite process. Results indicated that the PFOA defluorination rates increased with increasing nucleophilicity of halogens (I > Br > Cl). Meanwhile, the introduction of I-, Br-, and Cl- reduced the interference of the coexisting water matrix on the degrading influence of PFOA. The in situ produced eaq-, SO3•-, H•, and HO• were recognized, among the addition of I- maximized the relative contribution of eaq- but Br- and Cl- decreased that of H• and other radicals. Additionally, HPLC/MS analysis revealed the presence of I-, Br-, and Cl- had a vital impact on the difference in product concentrations, while they had a negligible effect on the change in the pathway of degradation. Overall, this study demonstrated the similarities and differences between I-, Br-, and Cl-, which has significant implications for further understanding VUV/sulfite degradation.
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Affiliation(s)
- Changlan Hou
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Jiaqin Deng
- College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, PR China
| | - Shanhong Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Hui Li
- Hunan Academy of Forestry and State Key Laboratory of Utilization of Woody Oil Resource, Changsha 410004, PR China
| | - Yin Zhou
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Yunbo Zhai
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
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21
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Li B, Pan H, Chen B. A review of factors affecting the formation and roles of primary and secondary reactive species in UV 254-based advanced treatment processes. WATER RESEARCH 2023; 244:120537. [PMID: 37683496 DOI: 10.1016/j.watres.2023.120537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/10/2023] [Accepted: 08/27/2023] [Indexed: 09/10/2023]
Abstract
The presence of organic micropollutants (OMPs) in water has been threatening human health and aquatic ecosystems worldwide. Ultraviolet-based advanced treatment processes (UV-ATPs) are one of the most effective and promising technologies to transform OMPs in water; therefore, an increasing number of emerging UV-ATPs are proposed. However, appropriate selection of UV-ATPs for practical applications is challenging because each UV-ATP generates different types and concentrations of reactive species (RSs) that may not be sufficient to degrade specific types of OMPs. Furthermore, the concentrations and types of RSs are highly influenced by anions and dissolved organic matter (DOM) coexisting in real waters, making systematic understandings of their interfering mechanisms difficult. To identify and address the knowledge gaps, this review provides a comparison of the generations and variations of various types of RSs in different UV-ATPs. These analyses not only prove the importance of water matrices on formation and consumption of primary and secondary RSs under different conditions, but also highlight the non-negligible roles of optical properties and reactivities of DOM and anions. For example, different UV-ATPs may be applicable to different target OMPs under different conditions; and the concentrations and roles of secondary RSs may outperform those of primary RSs in OMP degradation for real applications. With continuous progress and outstanding achievements in the UV-ATPs, it is hoped that the findings and conclusions of this review could facilitate further research and application of UV-ATPs.
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Affiliation(s)
- Boqiang Li
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China
| | - Huimei Pan
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China
| | - Baiyang Chen
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China.
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22
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Cao Y, Li J, Zhao Y, Zhao Y, Qiu W, Pang S, Jiang J. Degradation of metoprolol by UV/sulfite as an advanced oxidation or reduction process: The significant role of oxygen. J Environ Sci (China) 2023; 128:107-116. [PMID: 36801026 DOI: 10.1016/j.jes.2022.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/05/2022] [Accepted: 07/05/2022] [Indexed: 06/18/2023]
Abstract
The degradation of metoprolol (MTP) by the UV/sulfite with oxygen as an advanced reduction process (ARP) and that without oxygen as an advanced oxidation process (AOP) was comparatively studied herein. The degradation of MTP by both processes followed the first-order rate law with comparable reaction rate constants of 1.50×10-3sec-1 and 1.20×10-3sec-1, respectively. Scavenging experiments demonstrated that both eaq- and H• played a crucial role in MTP degradation by the UV/sulfite as an ARP, while SO4•- was the dominant oxidant in the UV/sulfite AOP. The degradation kinetics of MTP by the UV/sulfite as an ARP and AOP shared a similar pH dependence with a minimum rate obtained around pH 8. The results could be well explained by the pH impacts on the MTP speciation and sulfite species. Totally six transformation products (TPs) were identified from MTP degradation by the UV/sulfite ARP, and two additional ones were detected in the UV/sulfite AOP. The benzene ring and ether groups of MTP were proposed as the major reactive sites for both processes based on molecular orbital calculations by density functional theory (DFT). The similar degradation products of MTP by the UV/sulfite process as an ARP and AOP indicated that eaq-/H• and SO4•- might share similar reaction mechanisms, primarily including hydroxylation, dealkylation, and H abstraction. The toxicity of MTP solution treated by the UV/sulfite AOP was calculated to be higher than that in the ARP by the Ecological Structure Activity Relationships (ECOSAR) software, due to the accumulation of TPs with higher toxicity.
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Affiliation(s)
- Ying Cao
- Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University at Zhuhai, Zhuhai 519087, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Juan Li
- Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University at Zhuhai, Zhuhai 519087, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Yanxin Zhao
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Yumeng Zhao
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Wei Qiu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Suyan Pang
- Key Laboratory of Songliao Aquatic Environment, Ministry of Education, School of Municipal and Environmental Engineering, Jilin Jianzhu University, Changchun 130118, China
| | - Jin Jiang
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
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23
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Isowamwen O, Li R, Holsen T, Thagard SM. Plasma-assisted degradation of a short-chain perfluoroalkyl substance (PFAS): Perfluorobutane sulfonate (PFBS). JOURNAL OF HAZARDOUS MATERIALS 2023; 456:131691. [PMID: 37236102 DOI: 10.1016/j.jhazmat.2023.131691] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/20/2023] [Accepted: 05/22/2023] [Indexed: 05/28/2023]
Abstract
This study investigates the degradation of perfluorobutane sulfonate (PFBS), a chemical compound belonging to a group of per- and polyfluoroalkyl substances (PFAS), by gas-phase electrical discharge plasma. Plasma alone was ineffective in degrading PFBS due to its poor hydrophobicity, which inhibited the compound from accumulating at the plasma-liquid interface, the region of chemical reactivity. To overcome bulk liquid mass transport limitations, a surfactant, hexadecyltrimethylammonium bromide (CTAB), was introduced to interact with and transport PFBS to the plasma-liquid interface. In the presence of CTAB, ∼99% of PFBS was removed from the bulk liquid and concentrated at the interface, where 67% of the concentrate was degraded and 43% of that amount was defluorinated within one hour. PFBS degradation was further improved by optimizing the surfactant concentration and dosage. Experiments with a range of cationic, non-ionic, and anionic surfactants revealed that the PFAS-CTAB binding mechanism is predominantly electrostatic. A mechanistic understanding of the PFAS-CTAB complex formation, its transport to and destruction at the interface is proposed, alongside the chemical degradation scheme, which includes the identified degradation byproducts. This study shows that surfactant-assisted plasma treatment is one of the most promising techniques for destroying short-chain PFAS in contaminated water.
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Affiliation(s)
- Osakpolo Isowamwen
- Department of Chemical and Biomolecular Engineering, Plasma Research Laboratory, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, USA
| | - Rui Li
- Department of Chemical and Biomolecular Engineering, Plasma Research Laboratory, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, USA
| | - Thomas Holsen
- Department of Civil and Environmental Engineering, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, USA
| | - Selma Mededovic Thagard
- Department of Chemical and Biomolecular Engineering, Plasma Research Laboratory, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, USA.
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24
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Chen X, Wang J, Wu H, Zhu Z, Zhou J, Guo H. Trade-off effect of dissolved organic matter on degradation and transformation of micropollutants: A review in water decontamination. JOURNAL OF HAZARDOUS MATERIALS 2023; 450:130996. [PMID: 36867904 DOI: 10.1016/j.jhazmat.2023.130996] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/24/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
The degradation of micropollutants by various treatments is commonly affected by the ubiquitous dissolved organic matter (DOM) in the water environment. To optimize the operating conditions and decomposition efficiency, it is necessary to consider the impacts of DOM. DOM exhibits varied behaviors in diverse treatments, including permanganate oxidation, solar/ultraviolet photolysis, advanced oxidation processes, advanced reduction process, and enzyme biological treatments. Besides, the different sources (i.e., terrestrial and aquatic, etc) of DOM, and operational circumstances (i.e., concentration and pH) fluctuate different transformation efficiency of micropollutants in water. However, so far, systematic explanations and summaries of relevant research and mechanism are rare. This paper reviewed the "trade-off" performances and the corresponding mechanisms of DOM in the elimination of micropollutants, and summarized the similarities and differences for the dual roles of DOM in each of the aforementioned treatments. Inhibition mechanisms typically include radical scavenging, UV attenuation, competition effect, enzyme inactivation, reaction between DOM and micropollutants, and intermediates reduction. Facilitation mechanisms include the generation of reactive species, complexation/stabilization, cross-coupling with pollutants, and electron shuttle. Moreover, electron-drawing groups (i.e., quinones, ketones functional groups) and electron-supplying groups (i.e., phenols) in the DOM are the main contributors to its trade-off effect.
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Affiliation(s)
- Xingyu Chen
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Jingquan Wang
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Han Wu
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Zhuoyu Zhu
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Jianfei Zhou
- National Engineering Research Center of Clean Technology in Leather Industry, Sichuan University, Chengdu 610065, China.
| | - Hongguang Guo
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China; Yibin Industrial Technology Research Institute of Sichuan University, Yibin 644000, China.
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25
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Trzcinski AP, Harada K. Adsorption of PFOS onto graphite intercalated compound and analysis of degradation by-products during electro-chemical oxidation. CHEMOSPHERE 2023; 323:138268. [PMID: 36870616 DOI: 10.1016/j.chemosphere.2023.138268] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/26/2023] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
Perfluorooctane sulfonate (PFOS) is a highly recalcitrant perfluoro chemical belonging to the family of per- and polyfluoroalkyl substances (PFAS). Its adsorption and degradation was demonstrated in a novel PFAS remediation process involving the adsorption onto graphite intercalated compounds (GIC) and the electrochemical oxidation. The Langmuir type of adsorption was characterized by a loading capacity of 53.9 μg PFOS g-1 GIC and a second order kinetics (0.021 g μg-1 min-1). Up to 99% of PFOS was degraded in the process with a half-life of 15 min. The breakdown by-products included short chain perfluoroalkane sulfonates such as Perfluoroheptanesulfonate (PFHpS), Perfluorohexanesulfonate (PFHxS), Perfluoropentanesulfonate (PFPeS) and Perfluorobutanesulfonate (PFBS), but also short chain perfluoro carboxylic acids such as perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxA) and perfluorobutanoic acid (PFBA) indicating different degradation pathways. These by-products could also be broken down but the shorter the chain the slower the degradation rate. This novel combined adsorption and electrochemical process offers an alternative treatment for PFAS contaminated waters.
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Affiliation(s)
- Antoine P Trzcinski
- School of Agriculture and Environmental Science, University of Southern Queensland, West Street, 4350, Queensland, Australia.
| | - Kouji Harada
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
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Zhou Z, Guo R, Chen B, Wang L, Cao H, Wei C, Hu M, Zhan Y, Li S, Wang Y, Liang Y. Development of a Completely New PFOS Alternative with Lower Surface Tension for Minimizing the Environmental Burden. Chem Res Chin Univ 2023; 39:408-414. [PMID: 37303471 PMCID: PMC10115474 DOI: 10.1007/s40242-023-3030-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 03/30/2023] [Indexed: 06/13/2023]
Abstract
Improving the technical performance of related industrial products is an efficient strategy to reducing the application quantities and environmental burden for toxic chemicals. A novel polyfluoroalkyl surfactant potassium 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonate(F404) was synthesized by a commercializable route. It had a surface tension(γ) of 18.2 mN/m at the critical micelle concentration(CMC, 1.04 g/L), significantly lower than that of perfluorooctane sulfonate(PFOS, ca. 33.0 mN/m, 0.72 g/L), and exhibited remarkable suppression of chromium-fog at a dose half that of PFOS. The half maximal inhibitory concentration(IC50) values in HepG2 cells and the lethal concentration of 50%(LC50) in zebrafish embryos after 72 hpf indicated a lower toxicity for F404 in comparison to PFOS. In a UV/sulphite system, 89.3% of F404 were decomposed after 3 h, representing a defluorination efficiency of 43%. The cleavage of the ether C-O bond during the decomposition would be expected to form a short chain·C4F9 as the position of the ether C-O in the F404 fluorocarbon chains is C4-O5. The ether unit is introduced in the perfluoroalkyl chain to improve water solubility, biocompatibility and degradation, thereby minimizing the environmental burden. Electronic Supplementary Material Supplementary material is available in the online version of this article at 10.1007/s40242-023-3030-4.
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Affiliation(s)
- Zhen Zhou
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
| | - Rui Guo
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
| | - Bolei Chen
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
| | - Ling Wang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
| | - Huiming Cao
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
| | - Cuiyun Wei
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
| | - Ming Hu
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
| | - Yuhang Zhan
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
| | - Shutao Li
- Hubei Hengxin Chemical Co., Ltd., Yingcheng, 432400 P. R. China
| | - Yawei Wang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 P. R. China
| | - Yong Liang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056 P. R. China
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27
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Hu Y, Zhan Y, Wei C, Chen F, Cheng J, Shen Y, Zhou Z, Wang L, Liang Y. Hydrochar coupled with iodide for efficient photodegradation of perfluorooctanoic acid and perfluorooctane sulfonic acid under ultraviolet light. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 868:161621. [PMID: 36649771 DOI: 10.1016/j.scitotenv.2023.161621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 06/17/2023]
Abstract
Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are typical emerging persistent organic pollutants that are raising concerns regarding their environmental persistence. The photodegradation of these chemicals in water can be promoted by generating hydrated electrons (eaq-). The present work demonstrates a highly efficient process combining ultraviolet (UV) radiation, hydrochar (H-BC) and KI that is capable of decomposing PFOA and PFOS. After 60 min of photolysis using this technique, 99.5 % and 94.1 % of the initial amounts of PFOA and PFOS in aqueous solution were degraded, respectively, with corresponding defluorination percentages of 87.8 % and 71.7 %, respectively. These degradation values were higher than the sum of those obtained using UV radiation with only H-BC or KI, implying a synergistic effect from the combination of H-BC and KI. This effect can be attributed to the unique structure and numerous oxygen-containing functional groups of the H-BC. This material was able to absorb PFOA and PFOS, reduce iodide oxidation products back to I-, act as an electron shuttle and shorten the diffusion distance to the target substrate. These factors all increased the probability of reactions between the contaminants and eaq-. Analyses by liquid chromatography/electrospray ionization/tandem mass spectrometry showed that short-chain perfluoroalkyl carboxylic acids with less than seven carbons were the primary degradation intermediates, suggesting that the photodegradation proceeded stepwise. These results confirmed the cooperative effect of the H-BC and iodide, leading to effective eaq- generation. This work is expected to facilitate the development of new strategies for the treatment of water systems contaminated with PFOA and PFOS.
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Affiliation(s)
- Yuning Hu
- Department of Chemistry, Wuhan University, Wuhan, PR China
| | - Yuhang Zhan
- Wuhan City College, Wuhan, PR China; Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, PR China
| | - Cuiyun Wei
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, PR China
| | - Fengjie Chen
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, PR China
| | - Jing Cheng
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, PR China
| | - Yunxiang Shen
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, PR China
| | - Zhen Zhou
- Department of Chemistry, Wuhan University, Wuhan, PR China; Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, PR China.
| | - Ling Wang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, PR China
| | - Yong Liang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, PR China
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28
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Bowers BB, Lou Z, Xu J, De Silva AO, Xu X, Lowry GV, Sullivan RC. Nontarget analysis and fluorine atom balances of transformation products from UV/sulfite degradation of perfluoroalkyl contaminants. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:472-483. [PMID: 36722905 DOI: 10.1039/d2em00425a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a class of thousands of highly fluorinated, anthropogenic compounds that are used in a wide variety of consumer applications. Due to their widespread use and high persistence, PFAS are ubiquitous in drinking water, which is of concern due to the threats these compounds pose to human health. Reduction via the hydrated electron is a promising technology for PFAS remediation and has been well-studied. However, since previous work rarely reports fluorine atom balances and often relies on suspect screening, some transformation products are likely unaccounted for. Therefore, we performed non-target analysis using high-resolution mass spectrometry on solutions of perfluorooctanesulfonate (PFOS), perfluorobutanesulfonate (PFBS), perfluorooctanoate (PFOA), and 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate (GenX) that had been treated with UV/sulfite to produce hydrated electrons. We determined fluorine atom balances for all compounds studied, finding high fluorine atom balances for PFOS and PFBS. PFOA and GenX had lower overall fluorine atom balances, likely due to the production of volatile or very polar transformation products that were not measured by our methods. Transformation products identified by our analysis were consistent with literature, with a few exceptions. Namely, shorter-chain perfluorosulfonates (PFSA) and their H/F substituted counterparts were also detected from PFOS. This is an unexpected result based on literature, as no documented pathway exists for the formation of shorter-chain PFSA during UV/sulfite treatment. Furthermore, the nontarget approach we employed allowed for identification of novel, unsaturated products from the hydrated electron treatment of perfluorooctanesulfonate (PFOS) that warrant further investigation.
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Affiliation(s)
- Bailey B Bowers
- Institute for Green Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Zimo Lou
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, Zhejiang, China
| | - Jiang Xu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Amila O De Silva
- Environment and Climate Change Canada, Burlington, Ontario, L7S 1A1, Canada
| | - Xinhua Xu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Gregory V Lowry
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Ryan C Sullivan
- Institute for Green Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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29
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So HL, Wang L, Liu J, Chu W, Li T, Abdelhaleem A. Insights into the degradation of diphenhydramine - An emerging SARS-CoV-2 medicine by UV/Sulfite. Sep Purif Technol 2022; 303:122193. [PMID: 36168647 PMCID: PMC9502506 DOI: 10.1016/j.seppur.2022.122193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/18/2022] [Accepted: 09/19/2022] [Indexed: 11/28/2022]
Abstract
As Diphenhydramine (DPH) has been considered as a drug to treat SARS-CoV-2, the degradation of DPH from water was investigated and evaluated in this study by adopting an advanced oxidation/advanced reduction process - the UV/sulfite process. The UV/sulfite system was able to eliminate DPH within 6 mins under UV254nm and 1.0 mM sulfite. It was observed that the presence ofN O 3 - ,N O 2 - ,C l - ,H C O 3 - , andS O 4 2 - anions in water can affect the performance of UV/Sulfite degradation system. The mechanism of UV/sulfite/anions was evaluated which the presence ofN O 3 - in UV/sulfite process has revealed faster initial decay rate but lower final DPH removal. It was observed that the UV/Sulfite process was extremely sensitive to pH as the dissociation of ion species varied among pH. The reaction became sluggish in acidic solution due to the dissociation of less reactive species such as HSO3 -. In alkaline solution, SO3 2- was the dominant species, producing powerfulSO 3 ∙ - ande aq - when activated by UV at 254 nm. By conducting LC/MS analysis, the degradation pathway was proposed and can be summarized into four main pathways: hydroxylation, side chain cleavage, losing aromatic ring or ring opening. Scavenging tests were also carried out and validated the presence of various radicals contributing to the reaction, includinge aq - , H˙, OH˙, SO3 ˙-, O2 •- and SO4 ˙-.
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Affiliation(s)
- Hiu Lam So
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Liwen Wang
- Department of Civil and Environmental Engineering, University of California, Berkeley, 760 Davis Hall, Berkeley, CA 94720, United States
| | - Jianghui Liu
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Wei Chu
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Tao Li
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Amal Abdelhaleem
- Environmental Engineering Department, Egypt-Japan University of Science and Technology, New Borg El-Arab City, Alexandria 21934, Egypt
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30
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Yuan Y, Feng L, He X, Wu M, Ai Z, Zhang L, Gong J. Nitrate promoted defluorination of perfluorooctanoic acid in UV/sulfite system: Coupling hydrated electron/reactive nitrogen species-mediated reduction and oxidation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 313:120172. [PMID: 36115490 DOI: 10.1016/j.envpol.2022.120172] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/28/2022] [Accepted: 09/09/2022] [Indexed: 06/15/2023]
Abstract
A significantly accelerated defluorination of recalcitrant perfluorooctanoic acid (PFOA) was explored with the co-present nitrate (20 mg L-1) by UV/sulfite treatment (UV/sulfite-nitrate). The deep defluorination of PFOA and complete denitrification of nitrate were simultaneously achieved in UV/sulfite-nitrate system. At the initial 30 min, PFOA defluorination exhibited an induction period, exactly corresponding to the removal of the co-existed nitrate. Upon the induction period passed, an accelerated removal of PFOA (5 mg L-1) occurred, nearly 100% defluorination ratio reached within 2 h. Compared with those in UV/sulfite, the kinetics of PFOA decay, defluorination, and transformation product formations were greatly enhanced in UV/sulfite-nitrate system. Reactive nitrogen species (RNS) generated from eaq--induced reduction of nitrate were found to play significant roles on the promoted defluorination apart from eaq--mediated reductive defluorination. The investigations on solution pH (7.0-11.0) confirmed that the reductive defluorination of PFOA was more efficient under alkaline conditions, however, the presence of nitrate can promote the defluorination even under neutral pH. Theoretical calculations of Fukui function demonstrated that RNS could easily launch electrophilic attack toward H-rich moieties of fluorotelomer carboxylates (FTCAs, CnF2n+1-(CH2)m-COO-), more persistent intermediates (formed via H/F exchange), and convert FTCAs into shorter-chain perfluorinated carboxylic acids, thus facilitating the deep defluorination. Along with the analysis on the denitrification products, the liberation of fluoride ions and generated intermediates, possible decomposition pathways were proposed. This work highlights the indispensable synergy from eaq-/RNS with integrated reduction and oxidation on PFOA defluorination and will advance remediation technologies of perfluorinated compound contaminated water.
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Affiliation(s)
- Yijin Yuan
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China
| | - Lizhen Feng
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China
| | - Xianqin He
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China
| | - Mengsi Wu
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China
| | - Zhihui Ai
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China
| | - Lizhi Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China
| | - Jingming Gong
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China.
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31
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Londhe K, Lee CS, McDonough CA, Venkatesan AK. The Need for Testing Isomer Profiles of Perfluoroalkyl Substances to Evaluate Treatment Processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15207-15219. [PMID: 36314557 PMCID: PMC9670843 DOI: 10.1021/acs.est.2c05518] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 10/12/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
Many environmentally relevant poly-/perfluoroalkyl substances (PFASs) including perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) exist in different isomeric (branched and linear) forms in the natural environment. The isomeric distribution of PFASs in the environment and source waters is largely controlled by the source of contamination and varying physicochemical properties imparted by their structural differences. For example, branched isomers of PFOS are relatively more reactive and less sorptive compared to the linear analogue. As a result, the removal of branched and linear PFASs during water treatment can vary, and thus the isomeric distribution in source waters can influence the overall efficiency of the treatment process. In this paper, we highlight the need to consider the isomeric distribution of PFASs in contaminated matrices while designing appropriate remediation strategies. We additionally summarize the known occurrence and variation in the physicochemical properties of PFAS isomers influencing their detection, fate, toxicokinetics, and treatment efficiency.
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Affiliation(s)
- Kaushik Londhe
- Department
of Civil Engineering, Stony Brook University, Stony Brook, New York 11794, United States
- New
York State Center for Clean Water Technology, Stony Brook University, Stony
Brook, New York 11794, United States
| | - Cheng-Shiuan Lee
- New
York State Center for Clean Water Technology, Stony Brook University, Stony
Brook, New York 11794, United States
- Research
Center for Environmental Changes, Academia
Sinica, Taipei 115, Taiwan
| | - Carrie A. McDonough
- Department
of Civil Engineering, Stony Brook University, Stony Brook, New York 11794, United States
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Arjun K. Venkatesan
- Department
of Civil Engineering, Stony Brook University, Stony Brook, New York 11794, United States
- New
York State Center for Clean Water Technology, Stony Brook University, Stony
Brook, New York 11794, United States
- School
of Marine and Atmospheric Sciences, Stony
Brook University, Stony Brook, New York 11794, United States
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Tenorio R, Maizel AC, Schaefer CE, Higgins CP, Strathmann TJ. Application of High-Resolution Mass Spectrometry to Evaluate UV-Sulfite-Induced Transformations of Per- and Polyfluoroalkyl Substances (PFASs) in Aqueous Film-Forming Foam (AFFF). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14774-14787. [PMID: 36162863 DOI: 10.1021/acs.est.2c03228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
UV-sulfite has been shown to effectively degrade per- and polyfluoroalkyl substances (PFASs) in single-solute experiments. We recently reported treatment of 15 PFASs, including perfluoroalkyl sulfonic acids (PFSAs), perfluoroalkyl carboxylic acids (PFCAs), and fluorotelomer sulfonic acids (FTSs), detected in aqueous film-forming foam (AFFF) using high-resolution liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) targeted analysis. Here, we extend the analysis within those original reaction solutions to include the wider set of PFASs in AFFF for which reactivity is largely unknown by applying recently established LC-QTOF-MS suspect screening and semiquantitative analysis protocols. Sixty-eight additional PFASs were detected (15 targeted + 68 suspect screening = 83 PFASs) with semiquantitative analysis, and their behavior was binned on the basis of (1) detection in untreated AFFF, (2) PFAS photogeneration, and (3) reactivity. These 68 structures account for an additional 20% of the total fluorine content in the AFFF (targeted + suspect screening = 57% of total fluorine content). Structure-reactivity trends were also revealed. During treatment, transformations of highly reactive structures containing sulfonamide (-SO2N-) and reduced sulfur groups (e.g., -S- and -SO-) adjacent to the perfluoroalkyl [F(CF2)n-] or fluorotelomer [F(CF2)n(CH2)2-] chain are likely sources of PFCA, PFSA, and FTS generation previously reported during the early stages of reactions. The results also show the character of headgroup moieties adjacent to the F(CF2)n-/F(CF2)n(CH2)2- chain (e.g., sulfur oxidation state, sulfonamide type, and carboxylic acids) and substitution along the F(CF2)n- chain (e.g., H-, ketone, and ether) together may determine chain length-dependent reactivity trends. The results highlight the importance of monitoring PFASs outside conventional targeted analytical methodologies.
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Affiliation(s)
- Raul Tenorio
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, Illinois 61801, United States
- Department of Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States
| | - Andrew C Maizel
- Department of Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States
- Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, D.C. 20057, United States
| | - Charles E Schaefer
- CDM Smith, 110 Fieldcrest Avenue, Edison, New Jersey 08837, United States
| | - Christopher P Higgins
- Department of Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States
| | - Timothy J Strathmann
- Department of Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, United States
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Zhao Y, Zhang C, Chu L, Zhou Q, Huang B, Ji R, Zhou X, Zhang Y. Hydrated electron based photochemical processes for water treatment. WATER RESEARCH 2022; 225:119212. [PMID: 36223677 DOI: 10.1016/j.watres.2022.119212] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Hydrated electron (eaq-) based photochemical processes have emerged as a promising technology for contaminant removal in water due to the mild operating conditions. This review aims to provide a comprehensive and up-to-date summary on eaq- based photochemical processes for the decomposition of various oxidative contaminants. Specifically, the characteristics of different photo-reductive systems are first elaborated, including the environment required to generate sufficient eaq-, the advantages and disadvantages of each system, and the comparison of the degradation efficiency of contaminants induced by eaq-. In addition, the identification methods of eaq- (e.g., laser flash photolysis, scavenging studies, chemical probes and electron spin resonance techniques) are summarized, and the influences of operating conditions (e.g., solution pH, dissolved oxygen, source chemical concentration and UV type) on the performance of contaminants are also discussed. Considering the complexity of contaminated water, particular attention is paid to the influence of water matrix (e.g., coexisting anions, alkalinity and humic acid). Moreover, the degradation regularities of various contaminants (e.g., perfluorinated compounds, disinfection by-products and nitrate) by eaq- are summarized. We finally put forward several research prospects for the decomposition of contaminants by eaq- based photochemical processes to promote their practical application in water treatment.
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Affiliation(s)
- Yunmeng Zhao
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Chaojie Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
| | - Liquan Chu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Qi Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Baorong Huang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Ruixin Ji
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Xuefei Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Yalei Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
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Liu F, Guan X, Xiao F. Photodegradation of per- and polyfluoroalkyl substances in water: A review of fundamentals and applications. JOURNAL OF HAZARDOUS MATERIALS 2022; 439:129580. [PMID: 35905606 DOI: 10.1016/j.jhazmat.2022.129580] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/05/2022] [Accepted: 07/09/2022] [Indexed: 06/15/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are persistent, mobile, and toxic chemicals that are hazardous to human health and the environment. Several countries, including the United States, plan to set an enforceable maximum contamination level for certain PFAS compounds in drinking water sources. Among the available treatment options, photocatalytic treatment is promising for PFAS degradation and mineralization in the aqueous solution. In this review, recent advances in the abatement of PFAS from water using photo-oxidation and photo-reduction are systematically reviewed. Degradation mechanisms of PFAS by photo-oxidation involving the holes (hvb+) and oxidative radicals and photo-reduction using the electrons (ecb-) and hydrated electrons (eaq-) are integrated. The recent development of innovative heterogeneous photocatalysts and photolysis systems for enhanced degradation of PFAS is highlighted. Photodegradation mechanisms of alternative compounds, such as hexafluoropropylene oxide dimer acid (GenX) and chlorinated polyfluorinated ether sulfonate (F-53B), are also critically evaluated. This paper concludes by identifying major knowledge gaps and some of the challenges that lie ahead in the scalability and adaptability issues of photocatalysis for natural water treatment. Development made in photocatalysts design and system optimization forges a path toward sustainable treatment of PFAS-contaminated water through photodegradation technologies.
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Affiliation(s)
- Fuqiang Liu
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Xiaohong Guan
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
| | - Feng Xiao
- Department of Civil Engineering, University of North Dakota, 243 Centennial Drive Stop 8115, Grand Forks, ND 58202, United States.
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Liu W, Zhao C, Zhou S, Liu B, Cheng X, Xue Z, Zhu T. Effects of UV/Fe(II)/sulfite pre-treatment on NOM-enhanced Ca 2+ scaling during nanofiltration treatment: Fouling mitigation, mechanisms, and correlation analysis of membrane resistance. WATER RESEARCH 2022; 223:119025. [PMID: 36058094 DOI: 10.1016/j.watres.2022.119025] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/21/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
This study was aimed to evaluate the effects of a pre-treatment involving sulfite (S(IV)) synergistically activated by ultraviolet (UV)/Fe(II) on natural organic matter (NOM)-enhanced Ca2+ scaling during nanofiltration treatment. Based on the variations in the physicochemical properties and correlation analyses of irreversible resistance, the intrinsic fouling mechanisms were revealed from two aspects: bulk crystallization (interaction between NOM and inorganic ions) and surface crystallization (morphology of surface crystallization and a change in the Ca2+ concentration in the scaling layer). Furthermore, the degradation contribution rates of different free radicals during the UV/Fe(II)/S(IV) (UFS) treatment process were evaluated. During the reactions in the UFS, three free radicals (SO·-4, OH·- and e- aq) were generated, and in-situ Fe(III) was formed in-situ. The carboxyl groups of the NOM were attacked by the free radicals, resulting in decreased of carboxyl concentration and density. In addition, the bond between Ca2+ and NOM weakened, and hydrophobic (HPO) substances were mineralized. However, the Fe(III) formed in-situ was active and electropositive, competing with Ca2+ for the complexation active sites on the NOM. The synergy effect of bulk crystallization and surface crystallization led to a significant decrease in the particle size of feed solution. The crystal size and roughness of membrane surface also decreased, which was conducive to reducing the membrane irreversible resistance. Correlation analysis revealed that the HPO ratio, carboxyl density and particle size (> 100 nm) ratio were effective characterization parameters for predicting irreversible resistance. This study not only provides guidance for alleviating membrane fouling caused by NOM-enhanced Ca2+ scaling during the nanofiltration process, but also presents the rationality of irreversible resistance during nanofiltration process and various indicators with strong linear correlation.
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Affiliation(s)
- Wenkai Liu
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Changrong Zhao
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Shiqing Zhou
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Bin Liu
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha 410082, China.
| | - Xiaoxiang Cheng
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, China.
| | - Zhihao Xue
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Tingting Zhu
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha 410082, China
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36
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Gu Y, Song Z, Dong Z, Sun F, Jiang C, Qi J. Efficient degradation and deiodination of iopamidol by UV/sulfite process: Assessment of typical process parameters and transformation paths. ENVIRONMENT INTERNATIONAL 2022; 167:107383. [PMID: 35952467 DOI: 10.1016/j.envint.2022.107383] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/17/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Iopamidol (IPM) is widely used in medical clinical examination and treatment and has immeasurable harm to the ecological environment. The combination of UV and sulfite (UV/sulfite) process was developed to degrade IPM in this study. In contrast to that almost no removal of IPM was observed under sulfite reduction alone, the UV/sulfite process could efficiently reductively degrade IPM with the observed rate constant (kobs) of 2.08 min-1, which was nearly 4 times that of UV irradiation alone. The major active species in the UV/sulfite process were identified as hydrated electrons (eaq-) by employing active species scavengers. The influence of the initial pH, sulfite dosage, IPM concentration, UV intensity and common water matrix were evaluated. The degradation of IPM reached nearly 100% within only 2.5 min at pH 9, and kobs increased at higher initial sulfite dosages and greater UV intensities. HCO3- had a limited effect on the degradation of IPM, while humic acid (HA) was found to be a strong inhibitor in the UV/sulfite process. With the synergistic action of UV/sulfite, most of the iodine in IPM was found to release in the form of iodide ions (up to approximately 98%), and a few formed iodide-containing organic compounds, reducing significantly the toxicity of degradation products. Under direct UV irradiation and free radical reduction (mainly eaq-), 15 transformation intermediates of IPM were produced by amide hydrolysis, deiodination, hydroxyl radical addition and hydrogen abstraction reactions, in which free radical attack accounted for the main part. Consequently, the UV/sulfite process has a strong potential for IPM degradation in aquatic environments.
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Affiliation(s)
- Yurong Gu
- School of Material and Environmental Engineering, Shenzhen Polytechnic, Shenzhen 518055, China
| | - Zi Song
- School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Zijun Dong
- School of Civil and Traffic Engineering, Shenzhen University, Shenzhen 518055, China.
| | - Feiyun Sun
- School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Chengchun Jiang
- School of Material and Environmental Engineering, Shenzhen Polytechnic, Shenzhen 518055, China
| | - Jikun Qi
- School of Civil and Environmental Engineering, Shenyang Jianzhu University, Shenyang 110168, China
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37
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Wang J, Liu J, Peng X, He M, Hu X, Zhao J, Zhu F, Yang X, Kong L. Reductive removal of As(V) and As(III) from aqueous solution by the UV/sulfite process: Recovery of elemental arsenic. WATER RESEARCH 2022; 223:118981. [PMID: 35994788 DOI: 10.1016/j.watres.2022.118981] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 08/10/2022] [Accepted: 08/13/2022] [Indexed: 06/15/2023]
Abstract
The removal of arsenic (As(V) and As(III)) from contaminated water has attracted great attention. However, the generation of arsenic-containing hazardous waste by traditional methods has become an inevitable environmental problem. Herein, a UV/sulfite advanced reduction method was proposed to remove As(V) and As(III) from aqueous solution in the form of valuable elemental arsenic (As(0)), thus avoiding the generation of arsenic-containing hazardous waste. The results showed that greater than 99.9% of As(V) and As(III) were reduced to the high purity As(0) (> 99.5 wt%) with the residual arsenic concentration below 10 μg L-1. The hydrated electrons (eaq-), H• and SO3•- radicals are generated by the UV/sulfite process, of which eaq- and H• serve as reductants of As(V) and As(III) while the SO3•- radicals inhibit arsenic reduction by oxidizing arsenic. The effective quantum efficiency (Φ) for the formation of As(0) in the As(V) and As(III) removal process is approximately 0.0078 and 0.0055 mol/Einstein, respectively. The reduction of arsenic is favorable under alkaline conditions (pH > 9.0) due to the higher photolysis efficiency of SO32- than HSO3- (pKa = 7.2) and higher stability of eaq-/H• under alkaline conditions. The presence of dissolved oxygen (O2), NO2-, NO3-, CO32-, PO43- and humic acid (HA) inhibited arsenic reduction through light blocking or eaq-/H• scavenging effects while Cl-, SO42-, Ca2+ and Mg2+ had negligible effects on arsenic reduction. The proposed method can effectively remove and recover arsenic from contaminated water at a low cost, demonstrating feasibility for practical application. This study provides a novel technology for the reductive removal and recovery of arsenic from contaminated water.
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Affiliation(s)
- Jianbing Wang
- School of Chemical and Environmental Engineering, Beijing Campus, China University of Mining and Technology, Beijing, 100083, China
| | - Jiyong Liu
- School of Chemical and Environmental Engineering, Beijing Campus, China University of Mining and Technology, Beijing, 100083, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Beijing Key Laboratory of Industrial Wastewater Treatment and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Xianjia Peng
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Beijing Key Laboratory of Industrial Wastewater Treatment and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mengchang He
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Xingyun Hu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Beijing Key Laboratory of Industrial Wastewater Treatment and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Jinmin Zhao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Beijing Key Laboratory of Industrial Wastewater Treatment and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Feng Zhu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Beijing Key Laboratory of Industrial Wastewater Treatment and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xin Yang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Beijing Key Laboratory of Industrial Wastewater Treatment and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Linghao Kong
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Beijing Key Laboratory of Industrial Wastewater Treatment and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
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38
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Wang M, Cai Y, Zhou B, Yuan R, Chen Z, Chen H. Removal of PFASs from water by carbon-based composite photocatalysis with adsorption and catalytic properties: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 836:155652. [PMID: 35508243 DOI: 10.1016/j.scitotenv.2022.155652] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/24/2022] [Accepted: 04/28/2022] [Indexed: 05/27/2023]
Abstract
Per- and polyfluoroalkyl substances (PFASs) are a class of persistent organic pollutants widely distributed in aquatic environments. The adsorption and photocatalytic methods have been widely used to remove PFASs in water because of their respective advantages. Still, they have apparent defects when used alone. Therefore, the adsorption and photocatalytic technologies are combined through suitable preparation methods, and the excellent properties of the two are used to synergize the treatment of organic pollutants. This strategy of "concentrating" pollutants and then degrading them in a centralized manner plays an essential role in removing trace PFASs. Nevertheless, a review focusing on this kind of adsorption photocatalyst system is lacking. This review will fill this gap and provide a reference for developing a carbon-based composite photocatalyst. Firstly, different carbon-based composite photocatalysts are reviewed in detail, focusing on the differences in various composite materials' excellent adsorption and catalytic properties. Secondly, the factors influencing the removal effect of carbon-based composite photocatalysts are discussed. Thirdly, the removal mechanism of carbon-based composite photocatalysts is summarized in detail. The removal process involves two steps: adsorption and photodegradation. The adsorption process involves multiple cooperative adsorption mechanisms, and photocatalytic degradation includes oxidative and reductive degradation. Fourthly, the comparison of adsorption-photocatalysis with common treatment techniques (including removal rate, range of adaptation, cost, and the possibility of expanding application) is summarized. Finally, the prospects of carbon-based composite photocatalysts for repairing PFASs are given by evaluating the performance of different composites.
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Affiliation(s)
- Mingran Wang
- Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yanping Cai
- Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Beihai Zhou
- Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Rongfang Yuan
- Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhongbing Chen
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 16500 Prague, Czech Republic
| | - Huilun Chen
- Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
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39
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Fennell BD, Odorisio A, McKay G. Quantifying Hydrated Electron Transformation Kinetics in UV-Advanced Reduction Processes Using the Re-,UV Method. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10329-10338. [PMID: 35791772 DOI: 10.1021/acs.est.2c02003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Ultraviolet advanced reduction processes (UV-ARP) have garnered significant attention recently for the degradation of several hard to treat contaminants, including recalcitrant per- and polyfluoroalkyl substances (PFAS). The rate of contaminant degradation in UV-ARP is directly related to the available hydrated electron concentration ([eaq-]). However, reports of [eaq-] and other parameters typically used to characterize photochemical systems are not widely reported in the UV-ARP literature. Deploying monochloroacetate as a probe compound, we developed a method (Re-,UV) to quantify the time-based hydrated electron concentration ([eaq]t) available for contaminant degradation relative to inputted UV fluence. Measured [eaq]t was then used to understand the impact of eaq- rate of formation and scavenging capacity on the degradation of two contaminants─nitrate and perfluorooctane sulfonate (PFOS)─in four source waters with varying background water quality. The results show that the long-term treatability of PFOS by UV-ARP is not significantly impacted by the initial eaq- scavenging conditions but rather is influenced by the presence of eaq- scavengers like dissolved organic carbon and bicarbonate. Lastly, using [eaq]t, degradation of nitrate and PFOS was modeled in the source waters. We demonstrate that the Re-,UV method provides an effective tool to assess UV-ARP treatment performance in a variety of source waters.
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Affiliation(s)
- Benjamin D Fennell
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77845, United States
| | - Adam Odorisio
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77845, United States
| | - Garrett McKay
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77845, United States
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40
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Wen Y, Rentería-Gómez Á, Day GS, Smith MF, Yan TH, Ozdemir ROK, Gutierrez O, Sharma VK, Ma X, Zhou HC. Integrated Photocatalytic Reduction and Oxidation of Perfluorooctanoic Acid by Metal-Organic Frameworks: Key Insights into the Degradation Mechanisms. J Am Chem Soc 2022; 144:11840-11850. [PMID: 35732040 DOI: 10.1021/jacs.2c04341] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The high porosity and tunability of metal-organic frameworks (MOFs) have made them an appealing group of materials for environmental applications. However, their potential in the photocatalytic degradation of per- and polyfluoroalkyl substances (PFAS) has been rarely investigated. Hereby, we demonstrate that over 98.9% of perfluorooctanoic acid (PFOA) was degraded by MIL-125-NH2, a titanium-based MOF, in 24 h under Hg-lamp irradiation. The MOF maintained its structural integrity and porosity after three cycles, as indicated by its crystal structure, surface area, and pore size distribution. Based on the experimental results and density functional theory (DFT) calculations, a detailed reaction mechanism of the chain-shortening and H/F exchange pathways in hydrated electron (eaq-)-induced PFOA degradation were revealed. Significantly, we proposed that the coordinated contribution of eaq- and hydroxyl radical (•OH) is vital for chain-shortening, highlighting the importance of an integrated system capable of both reduction and oxidation for efficient PFAS degradation in water. Our results shed light on the development of effective and sustainable technologies for PFAS breakdown in the environment.
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Affiliation(s)
- Yinghao Wen
- Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Ángel Rentería-Gómez
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Gregory S Day
- Framergy Inc., 800 Raymond Stotzer Pkwy, College Station, Texas 77945, United States
| | - Mallory F Smith
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Tian-Hao Yan
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Ray Osman K Ozdemir
- Framergy Inc., 800 Raymond Stotzer Pkwy, College Station, Texas 77945, United States
| | - Osvaldo Gutierrez
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Virender K Sharma
- Program for the Environment and Sustainability, Department of Environmental and Occupational Health, Texas A&M University, College Station, Texas 77843, United States
| | - Xingmao Ma
- Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Hong-Cai Zhou
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States.,Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
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Biswas S, Yamijala SSRKC, Wong BM. Degradation of Per- and Polyfluoroalkyl Substances with Hydrated Electrons: A New Mechanism from First-Principles Calculations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:8167-8175. [PMID: 35481774 PMCID: PMC10365488 DOI: 10.1021/acs.est.2c01469] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Per- and polyfluoroalkyl substances (PFASs) are synthetic contaminants found in drinking groundwater sources and a wide variety of consumer products. Because of their adverse environmental and human health effects, remediation of these persistent compounds has attracted significant recent attention. To gain mechanistic insight into their remediation, we present the first ab initio study of PFAS degradation via hydrated electrons─a configuration that has not been correctly considered in previous computational studies up to this point. To capture these complex dynamical effects, we harness ab initio molecular dynamics (AIMD) simulations to probe the reactivities of perfluorooctanoic (PFOA) and perfluorooctane sulfonic acid (PFOS) with hydrated electrons in explicit water. We complement our AIMD calculations with advanced metadynamics sampling techniques to compute free energy profiles and detailed statistical analyses of PFOA/PFOS dynamics. Although our calculations show that the activation barrier for C-F bond dissociation in PFOS is three times larger than that in PFOA, all the computed free energy barriers are still relatively low, resulting in a diffusion-limited process. We discuss our results in the context of recent studies on PFAS degradation with hydrated electrons to give insight into the most efficient remediation strategies for these contaminants. Most importantly, we show that the degradation of PFASs with hydrated electrons is markedly different from that with excess electrons/charges, a common (but largely incomplete) approach used in several earlier computational studies.
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Affiliation(s)
- Sohag Biswas
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, Department of Physics & Astronomy, and Department of Chemistry, University of California-Riverside, Riverside, California 92521, United States
| | - Sharma S R K C Yamijala
- Department of Chemistry and Center for Atomistic Modelling and Materials Design, Indian Institute of Technology-Madras, Chennai 6000036, India
| | - Bryan M Wong
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, Department of Physics & Astronomy, and Department of Chemistry, University of California-Riverside, Riverside, California 92521, United States
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42
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Zhang Y, Chu W. Enhanced degradation of metronidazole by cobalt doped TiO2/sulfite process under visible light. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.120900] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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43
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Fennell B, Mezyk SP, McKay G. Critical Review of UV-Advanced Reduction Processes for the Treatment of Chemical Contaminants in Water. ACS ENVIRONMENTAL AU 2022; 2:178-205. [PMID: 37102145 PMCID: PMC10114900 DOI: 10.1021/acsenvironau.1c00042] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
UV-advanced reduction processes (UV-ARP) are an advanced water treatment technology characterized by the reductive transformation of chemical contaminants. Contaminant abatement in UV-ARP is most often accomplished through reaction with hydrated electrons (eaq -) produced from UV photolysis of chemical sensitizers (e.g., sulfite). In this Review, we evaluate the photochemical kinetics, substrate scope, and optimization of UV-ARP. We find that quantities typically reported in photochemical studies of natural and engineered systems are under-reported in the UV-ARP literature, especially the formation rates, scavenging capacities, and concentrations of key reactive species like eaq -. The absence of these quantities has made it difficult to fully evaluate the impact of operating conditions and the role of water matrix components on the efficiencies of UV-ARP. The UV-ARP substrate scope is weighted heavily toward contaminant classes that are resistant to degradation by advanced oxidation processes, like oxyanions and per- and polyfluoroalkyl substances. Some studies have sought to optimize the UV-ARP treatment of these contaminants; however, a thorough evaluation of the impact of water matrix components like dissolved organic matter on these optimization strategies is needed. Overall, the data compilation, analysis, and research recommendations provided in this Review will assist the UV-ARP research community in future efforts toward optimizing UV-ARP systems, modeling the eaq --based chemical transformation kinetics, and developing new UV-ARP systems.
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Affiliation(s)
- Benjamin
D. Fennell
- Zachry
Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Stephen P. Mezyk
- Department
of Chemistry and Biochemistry, California
State University, Long Beach, Long Beach, California 90840, United States
| | - Garrett McKay
- Zachry
Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
- . Phone: 979-458-6540
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44
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Liu G, Feng C, Shao P. Degradation of Perfluorooctanoic Acid with Hydrated Electron by a Heterogeneous Catalytic System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:6223-6231. [PMID: 34941262 DOI: 10.1021/acs.est.1c06793] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hydrated electron (eaq-)-induced reduction protocols have bright prospects for the decomposition of recalcitrant organic pollutants. However, traditional eaq- production involves homogeneous sulfite photolysis, which has a pH-dependent reaction activity and might have potential secondary pollution risks. In this study, a heterogeneous UV/diamond catalytic system was proposed to decompose of a typical persistent organic pollutant, perfluorooctanoic acid (PFOA). In contrast to the rate constant of the advanced reduction process (ARP) of a UV/SO32-, the kobs of PFOA decomposition in the UV/diamond system showed only minor pH dependence, ranging from 0.01823 ± 0.0014 min-1 to 0.02208 ± 0.0013 min-1 (pH 2 to pH 11). As suggested by the electron affinity (EA) and electron configuration of the diamond catalyst, the diamond catalyst yields facile energetic photogenerated electron emission into water without a high energy barrier after photoexcitation, thus inducing eaq- production. The impact of radical scavengers, electron spin resonance (ESR), and transient absorption (TA) measurements verified the formation of eaq- in the UV/diamond system. The investigation of diamond for ejection of energetic photoelectrons into a water matrix represents a new paradigm for ARPs and would facilitate future applications of heterogeneous catalytic processes for efficient recalcitrant pollutant removal by eaq-.
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Affiliation(s)
- Guoshuai Liu
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Cuijie Feng
- Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Penghui Shao
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle and National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resource Utilization, Nanchang Hangkong University, Nanchang 330063, China
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45
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Liu X, Duan X, Bao T, Hao D, Chen Z, Wei W, Wang D, Wang S, Ni BJ. High-performance photocatalytic decomposition of PFOA by BiOX/TiO 2 heterojunctions: Self-induced inner electric fields and band alignment. JOURNAL OF HAZARDOUS MATERIALS 2022; 430:128195. [PMID: 35180518 DOI: 10.1016/j.jhazmat.2021.128195] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/16/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Abstract
BiOX (X = Cl, Br and I) and BiOX/TiO2 photocatalysts were prepared by a facile hydrothermal approach. The BiOX/TiO2 heterojunctions demonstrated significantly enhanced efficiency for photocatalytic decomposition of perfluorooctanoic acid (PFOA) compared with sole BiOX or TiO2. PFOA (10 mg L1) was completely degraded by BiOCl(Br)/TiO2 in 8 h. Moreover, BiOCl/TiO2 attained deep decomposition of PFOA with a high defluorination ratio of 82%. The p-n heterojunctions between BiOX and TiO2 were confirmed by a series of characterizations. The photo-induced holes would migrate from the valance band (VB) of TiO2 to BiOX, driven by the built-in electric field (BIEF) near the interfaces of p-n heterojunctions, the inner electric fields (IEF) in BiOX and the higher VB position of BiOX. The X-ray diffraction (XRD) and TEM characterizations indicated that TiO2 combined with BiOX along the [110] facet, which facilitated photo-induced electron transfer in the [001] direction, thus benefiting PFOA decomposition.
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Affiliation(s)
- Xiaoqing Liu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Xiaoguang Duan
- School of Chemical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Teng Bao
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Derek Hao
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Zhijie Chen
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China.
| | - Shaobin Wang
- School of Chemical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
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46
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Yamijala SSRKC, Shinde R, Hanasaki K, Ali ZA, Wong BM. Photo-induced degradation of PFASs: Excited-state mechanisms from real-time time-dependent density functional theory. JOURNAL OF HAZARDOUS MATERIALS 2022; 423:127026. [PMID: 34481387 DOI: 10.1016/j.jhazmat.2021.127026] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/17/2021] [Accepted: 08/22/2021] [Indexed: 06/13/2023]
Abstract
Per- and polyfluoroalkyl substances (PFASs) are hazardous, carcinogenic, and bioaccumulative contaminants found in drinking water sources. To mitigate and remove these persistent pollutants, recent experimental efforts have focused on photo-induced processes to accelerate their degradation; however, the mechanistic details of these promising degradation processes remain unclear. To shed crucial insight on these electronic-excited state processes, we present the first study of photo-induced degradation of explicitly-solvated PFASs using excited-state, real-time time-dependent density functional theory (RT-TDDFT) calculations. Furthermore, our large-scale RT-TDDFT calculations show that these photo-induced excitations can be highly selective by enabling a charge-transfer process that only dissociates the CF bond while keeping the surrounding water molecules intact. Collectively, the RT-TDDFT techniques used in this work (1) enable a new capability for probing photo-induced mechanisms that cannot be gleaned from conventional ground-state DFT calculations and (2) provide a rationale for understanding ongoing experiments that are actively exploring photo-induced degradation of PFASs and other environmental contaminants.
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Affiliation(s)
- Sharma S R K C Yamijala
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, Department of Chemistry, and Department of Physics & Astronomy, University of California Riverside, Riverside, CA 92521, USA; Department of Chemistry and Center for Atomistic Modelling and Materials Design, Indian Institute of Technology Madras, Chennai 600036, India
| | - Ravindra Shinde
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, Department of Chemistry, and Department of Physics & Astronomy, University of California Riverside, Riverside, CA 92521, USA
| | - Kota Hanasaki
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, Department of Chemistry, and Department of Physics & Astronomy, University of California Riverside, Riverside, CA 92521, USA
| | - Zulfikhar A Ali
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, Department of Chemistry, and Department of Physics & Astronomy, University of California Riverside, Riverside, CA 92521, USA
| | - Bryan M Wong
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, Department of Chemistry, and Department of Physics & Astronomy, University of California Riverside, Riverside, CA 92521, USA.
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Yu X, Tan L, Yu Y, Xia Y, Guan Z, Gu J, Wang J, Chen H, Jiang F. Insights into the hydrated electron generation from UV/aniline: Mechanism and quantum efficiency. CHEMOSPHERE 2022; 287:132292. [PMID: 34562711 DOI: 10.1016/j.chemosphere.2021.132292] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/08/2021] [Accepted: 09/17/2021] [Indexed: 06/13/2023]
Abstract
The insight into the neglected reduction process accompanied by UV-based oxidation process may provide new ideas for the development of advanced oxidation and reduction technologies. In this study, aniline was comprehensively investigated as an unexpected indicator of hydrated electron (eaq-) under UV irradiation. Monochloroacetic acid (MCAA) was selected as the probe of eaq- and the balance of chloride ions indicated the reduction of MCAA. Further, laser flash photolysis experiments demonstrated the generation of eaq- in the UV/aniline process and the half-life period of formed eaq- was demonstrated to be 0.13 μs. The photolysis of aniline along with the decay of the excited state of aniline was responsible for the eaq- generation. Besides, the hydrogen atom (H) generated from the photolysis can subsequently reacted with OH- to generate eaq-. The photolysis pathways of aniline were proposed by the results of GC-MS. Aniline was abstracted of H in solution to the formation of aniline radical (PhNH) or form aminophenol in three different isomers (orto-, meta- and para-aminophenol). Moreover, UV/aniline showed a higher reducing capacity of MCAA compared with other organic electron donors and sustained a highly reducing ability in a wide pH. And the calculation results of quantum efficiency (Φ) showed that excessive aniline was not conducive to the elevation of Φ. This study introduced a novel pathway of eaq- generation during the photolysis of aniline and provided a new perspective for eaq--based advanced reduction processes.
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Affiliation(s)
- Xiaoping Yu
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Ling Tan
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Yalin Yu
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Yun Xia
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Zhen Guan
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Jia Gu
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Jing Wang
- Institute of Chemistry, Henan Academy of Sciences, Zhengzhou, 450002, China
| | - Huan Chen
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
| | - Fang Jiang
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
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48
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Fu L, Peng X, Chen Q, Ding Y, Jiang J. Photochemical degradation and debromination of bromophenols: Overlooked role of hydrated electron. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2021.119862] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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49
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He H, Li Y, Shen R, Shim H, Zeng Y, Zhao S, Lu Q, Mai B, Wang S. Environmental occurrence and remediation of emerging organohalides: A review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 290:118060. [PMID: 34479159 DOI: 10.1016/j.envpol.2021.118060] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/02/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
As replacements for "old" organohalides, such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), "new" organohalides have been developed, including decabromodiphenyl ethane (DBDPE), short-chain chlorinated paraffins (SCCPs), and perfluorobutyrate (PFBA). In the past decade, these emerging organohalides (EOHs) have been extensively produced as industrial and consumer products, resulting in their widespread environmental distribution. This review comprehensively summarizes the environmental occurrence and remediation methods for typical EOHs. Based on the data collected from 2015 to 2021, these EOHs are widespread in both abiotic (e.g., dust, air, soil, sediment, and water) and biotic (e.g., bird, fish, and human serum) matrices. A significant positive correlation was found between the estimated annual production amounts of EOHs and their environmental contamination levels, suggesting the prohibition of both production and usage of EOHs as a critical pollution-source control strategy. The strengths and weaknesses, as well as the future prospects of up-to-date remediation techniques, such as photodegradation, chemical oxidation, and biodegradation, are critically discussed. Of these remediation techniques, microbial reductive dehalogenation represents a promising in situ remediation method for removal of EOHs, such as perfluoroalkyl and polyfluoroalkyl substances (PFASs) and halogenated flame retardants (HFRs).
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Affiliation(s)
- Haozheng He
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, 510006, China
| | - Yiyang Li
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, 510006, China
| | - Rui Shen
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, 510006, China
| | - Hojae Shim
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, 999078, China
| | - Yanhong Zeng
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Siyan Zhao
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Qihong Lu
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, 510006, China; State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
| | - Bixian Mai
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Shanquan Wang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou, 510006, China
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50
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Reductive and Oxidative UV Degradation of PFAS—Status, Needs and Future Perspectives. WATER 2021. [DOI: 10.3390/w13223185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) consist of a group of environmentally persistent, toxic and bio-accumulative organic compounds of industrial origin that are widely present in water and wastewater. Despite restricted use due to current regulations on their use, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) remain the most commonly detected long-chain PFAS. This article reviews UV-based oxidative and reductive studies for the degradation of PFAS. Most of the UV-based processes studied at lab-scale include low pressure mercury lamps (emitting at 254 and 185 nm) with some studies using medium pressure mercury lamps (200–400 nm). A critical evaluation of the findings is made considering the degradation of PFAS, the impact of water quality conditions (pH, background ions, organics), types of oxidizing/reducing species, and source of irradiation with emphasis given to mechanisms of degradation and reaction by-products. Research gaps related to understanding of the factors influencing oxidative and reductive defluorination, impact of co-existing ions from the perspective of complexation with PFAS, and post-treatment toxicity are highlighted. The review also provides an overview of future perspectives regarding the challenges in relation to the current knowledge gaps, and future needs.
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