1
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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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2
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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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3
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He J, Boersma M, Song Z, Krebsbach S, Fan D, Duin EC, Wang D. Biochar and surfactant synergistically enhanced PFAS destruction in UV/sulfite system at neutral pH. CHEMOSPHERE 2024; 353:141562. [PMID: 38417493 DOI: 10.1016/j.chemosphere.2024.141562] [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: 11/18/2023] [Revised: 02/22/2024] [Accepted: 02/24/2024] [Indexed: 03/01/2024]
Abstract
The UV/sulfite-based advanced reduction process (ARP) emerges as an effective strategy to combat per- and polyfluoroalkyl substances (PFAS) pollution in water. Yet, the UV/sulfite-ARP typically operates at highly alkaline conditions (e.g., pH > 9 or even higher) since the generated reductive radicals for PFAS degradation can be quickly sequestered by protons (H+). To overcome the associated challenges, we prototyped a biochar-surfactant-system (BSS) to synergistically enhance PFAS sorption and degradation by UV/sulfite-ARP. The degradation and defluorination efficiencies of perfluorooctanoic acid (PFOA) depended on solution pH, and concentrations of surfactant (cetyltrimethylammonium bromide; CTAB), sulfite, and biochar. At high pH (8-10), adding biochar and BSS showed no or even small inhibitory effect on PFOA degradation, since the degradation efficiencies were already high enough that cannot be differentiated. However, at acidic and neutral pH (6-7), an evident enhancement of PFOA degradation and defluorination efficiencies occurred. This is due to the synergies between biochar and CTAB that create favorable microenvironments for enhanced PFOA sorption and deeper destruction by prolonging the longevity of reductive radicals (e.g., SO3•-), which is less affected by ambient pH conditions. The performance of UV/sulfite/BSS was further optimized and used for the degradation of four PFAS. At the optimal experimental condition, the UV/sulfite/BSS system can completely degrade PFOA with >30% defluorination efficiency for up to five continuous cycles (n = 5). Overall, our BSS provides a cost-effective and sustainable technique to effectively degrade PFAS in water under environmentally relevant pH conditions. The BSS-enabled ARP technique can be easily tied into PFAS treatment train technology (e.g., advanced oxidation process) for more efficient and deeper defluorination of various PFAS in water.
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Affiliation(s)
- Jianzhou He
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn university, Auburn, 36849, United States
| | - Melissa Boersma
- Department of Chemistry and Biochemistry, Auburn university, Auburn, 36849, United States
| | - Ziteng Song
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn university, Auburn, 36849, United States
| | - Samuel Krebsbach
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn university, Auburn, 36849, United States
| | - Dimin Fan
- Geosyntec Consultants, Inc, 10211 Wincopin Circle, 4th Floor, Columbia, 21044, United States
| | - Evert C Duin
- Department of Chemistry and Biochemistry, Auburn university, Auburn, 36849, United States
| | - Dengjun Wang
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn university, Auburn, 36849, United States.
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4
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Fennell B, Fowler D, Mezyk SP, McKay G. Reactivity of Dissolved Organic Matter with the Hydrated Electron: Implications for Treatment of Chemical Contaminants in Water with Advanced Reduction Processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7634-7643. [PMID: 37141499 PMCID: PMC10862553 DOI: 10.1021/acs.est.3c00909] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 05/06/2023]
Abstract
Advanced reduction processes (ARP) have garnered increasing attention for the treatment of recalcitrant chemical contaminants, most notably per- and polyfluoroalkyl substances (PFAS). However, the impact of dissolved organic matter (DOM) on the availability of the hydrated electron (eaq-), the key reactive species formed in ARP, is not completely understood. Using electron pulse radiolysis and transient absorption spectroscopy, we measured bimolecular reaction rates constant for eaq- reaction with eight aquatic and terrestrial humic substance and natural organic matter isolates ( kDOM,eaq-), with the resulting values ranging from (0.51 ± 0.01) to (2.11 ± 0.04) × 108 MC-1 s-1. kDOM,eaq- measurements at varying temperature, pH, and ionic strength indicate that activation energies for diverse DOM isolates are ≈18 kJ mol-1 and that kDOM,eaq- could be expected to vary by less than a factor of 1.5 between pH 5 and 9 or from an ionic strength of 0.02 to 0.12 M. kDOM,eaq- exhibited a significant, positive correlation to % carbonyl carbon for the isolates studied, but relationships to other DOM physicochemical properties were surprisingly more scattered. A 24 h UV/sulfite experiment employing chloroacetate as an eaq- probe revealed that continued eaq- exposure abates DOM chromophores and eaq- scavenging capacity over a several hour time scale. Overall, these results indicate that DOM is an important eaq- scavenger that will reduce the rate of target contaminant degradation in ARP. These impacts are likely greater in waste streams like membrane concentrates, spent ion exchange resins, or regeneration brines that have elevated DOM concentrations.
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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
| | - Douglas Fowler
- Department
of Chemistry and Biochemistry, California
State University Long Beach, Long Beach, California 90840, 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 77845, United States
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5
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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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6
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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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7
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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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8
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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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9
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Zhao Z, Xing L, Feng Q, Han L. A Novel Levulinate‐Based Highly Specific Colorimetric Fluorescent Probe for Bisulfite Detection in Live Cells and Zebrafish. ChemistrySelect 2022. [DOI: 10.1002/slct.202200385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Zhenhua Zhao
- Shandong Provincial Geomineral Engineering Exploration Institute Jinan 250014 China
| | - Liting Xing
- Shandong Provincial Geomineral Engineering Exploration Institute Jinan 250014 China
| | - Quanlin Feng
- Shandong Provincial Geomineral Engineering Exploration Institute Jinan 250014 China
| | - Lin Han
- Shandong Provincial Geomineral Engineering Exploration Institute Jinan 250014 China
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10
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Wacławek S, Ma X, Sharma VK, Xiao R, O'Shea KE, Dionysiou DD. Making waves: Defining advanced reduction technologies from the perspective of water treatment. WATER RESEARCH 2022; 212:118101. [PMID: 35092911 DOI: 10.1016/j.watres.2022.118101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 12/21/2021] [Accepted: 01/16/2022] [Indexed: 06/14/2023]
Abstract
Studies related to advanced reduction technologies (ARTs) have grown exponentially since the term was first coined in 2013. Despite recent interests in ARTs, the conditions and requirements for these processes have yet to be defined and clarifed. In comparision to well defined advanced oxidation technologies/processes (AOTs/AOPs) which involve the generation of hydroxyl radical as the common characteristic, ARTs function by electron donation from a variety of reducing agents and activators. Based on an extensive literature review, we propose that ARTs be defined as processes employing strong chemical reductants with E° ≤ -2.3 V vs. normal hydrogen electrode at 25 ºC. While extensive studies have revealed critical fundamental details of AOTs/AOPs mediated processes, there are still significant gaps in elucidation of the mechanistic details of reductive degradation/transformation of highly toxic compounds by ARTs. A significant number of pollutants and toxins resistant to AOTs/AOPs treatment are effectively degraded by ARTs. A great leap is needed on understanding ARTs to fully utilize their potential to efficiently remediate recalcitrant compounds of different sources and structures.
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Affiliation(s)
- Stanisław Wacławek
- Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 1402/2, 461 17, Liberec 1, Czech Republic.
| | - Xingmao Ma
- Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843, USA.
| | - Virender K Sharma
- Department of Environmental and Occupational Health, School of Public Health, Program for the Environment and Sustainability, Texas A&M University, 212 Adriance Lab Rd., 1266 TAMU, College Station, TX 77843, USA.
| | - Ruiyang Xiao
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China.
| | - Kevin E O'Shea
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA.
| | - Dionysios D Dionysiou
- Department of Chemical and Environmental Engineering (ChEE), Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012, USA.
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11
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Zhang J, Zhang H, Liu X, Cui F, Zhao Z. Efficient reductive and oxidative decomposition of haloacetic acids by the vacuum-ultraviolet/sulfite system. WATER RESEARCH 2022; 210:117974. [PMID: 35032895 DOI: 10.1016/j.watres.2021.117974] [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: 09/27/2021] [Revised: 12/08/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Haloacetic acids (HAAs), as a representative category of halogenated disinfection byproducts, are widely detected in disinfected water. In this work, the vacuum ultraviolet (VUV)/sulfite process under N2 saturated conditions was proposed to eliminate a series of HAAs (i.e., monochloroacetic acid (MCAA), difluoroacetic acid (DFAA), trifluoroacetic acid (TFAA), dichloroacetic acid (DCAA), etc.). The in situ generated hydrated electron (eaq-) demonstrated to be the main species to fulfill the initial degradation and dechlorination of MCAA, while hydroxyl radicals (˙OH) were in charge of the mineralization of MCAA. This means that the VUV/sulfite system is a combination of advanced reduction and oxidation processes (ARPs and AOPs). A significant enhancement of MCAA removal was observed with increasing pH values from 6.0 to 10.0, and surprisingly, kobs correlated well with the proportion of SO32- as the pH changed. This can be explained by the production of eaq- from VUV irradiation of SO32- rather than HSO3- and also due to eaq- being more stable under alkaline conditions. Increasing the sulfite dosage also elevated the degradation of MCAA. However, the addition of certain anions (i.e., chloride (Cl-), bicarbonate (HCO3-), and nitrate (NO3-)) and dissolved organic matter (DOM) inhibited the removal of MCAA to varying degrees. The VUV/sulfite system was effective toward various types of halogenated disinfection byproducts, supporting its broad applicability. Nevertheless, even in real waters, the VUV/sulfite system was also promising for the simultaneous abatement of HAAs and other oxyanions.
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Affiliation(s)
- Jing Zhang
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, P. R. China; Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, P. R. China
| | - Honglong Zhang
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, P. R. China
| | - Xin Liu
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, P. R. China
| | - Fuyi Cui
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, P. R. China; Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, P. R. China
| | - Zhiwei Zhao
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, P. R. China; Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, P. R. China.
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12
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Tenorio R, Liu J, Xiao X, Maizel A, Higgins CP, Schaefer CE, Strathmann TJ. Destruction of Per- and Polyfluoroalkyl Substances (PFASs) in Aqueous Film-Forming Foam (AFFF) with UV-Sulfite Photoreductive Treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:6957-6967. [PMID: 32343565 DOI: 10.1021/acs.est.0c00961] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Ultraviolet photochemical reaction of sulfite (SO32-) photosensitizer generates strongly reducing hydrated electrons (eaq-; NHE = -2.9 V) that have been shown to effectively degrade individual per- and polyfluoroalkyl substances (PFASs), including perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). However, treatment of complex PFAS mixtures in aqueous film-forming foam (AFFF) remains largely unknown. Here, UV-sulfite was applied to a diluted AFFF to characterize eaq- reactions with 15 PFASs identified by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) targeted analysis. Results show that reactivity varies widely among PFASs, but reaction rates observed for individual PFASs in AFFF are similar to rates observed in single-solute experiments. While some structures, including long-chain perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) were readily degraded, other structures, most notably short-chain PFSAs and fluorotelomer sulfonic acids (FTSs), were more recalcitrant. This finding is consistent with results showing incomplete fluoride ion release (up to 53% of the F content in AFFF) during reactions. Furthermore, results show that selected PFSAs, PFCAs, and FTSs can form as transient intermediates or unreactive end-products via eaq- reactions with precursor structures in AFFF. These results indicate that while UV-sulfite treatment can be effective for treating PFOS and PFOA to meet health advisory levels, remediation of the wider range of PFASs in AFFF will prove more challenging.
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Affiliation(s)
- Raul Tenorio
- University of Illinois at Urbana-Champaign, Department of Civil and Environmental Engineering, 205 North Mathews Avenue, Urbana, Illinois 61801, United States
- Colorado School of Mines, Department of Civil and Environmental Engineering, 1500 Illinois Street, Golden, Colorado 80401, United States
| | - Jinyong Liu
- University of California at Riverside, Department of Chemical and Environmental Engineering, 900 University Avenue, Riverside, California 92521, United States
| | - Xin Xiao
- Stanford University, Department of Materials Science and Engineering, 450 Serra Mall, Stanford, California 94305, United States
| | - Andrew Maizel
- Colorado School of Mines, Department of Civil and Environmental Engineering, 1500 Illinois Street, Golden, Colorado 80401, United States
| | - Christopher P Higgins
- Colorado School of Mines, Department of Civil and Environmental Engineering, 1500 Illinois Street, Golden, Colorado 80401, United States
| | - Charles E Schaefer
- CDM Smith, 110 Fieldcrest Avenue, Edison, New Jersey 08837, United States
| | - Timothy J Strathmann
- Colorado School of Mines, Department of Civil and Environmental Engineering, 1500 Illinois Street, Golden, Colorado 80401, United States
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Bentel MJ, Yu Y, Xu L, Kwon H, Li Z, Wong BM, Men Y, Liu J. Degradation of Perfluoroalkyl Ether Carboxylic Acids with Hydrated Electrons: Structure-Reactivity Relationships and Environmental Implications. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:2489-2499. [PMID: 31999101 DOI: 10.1021/acs.est.9b05869] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This study explores structure-reactivity relationships for the degradation of emerging perfluoroalkyl ether carboxylic acid (PFECA) pollutants with ultraviolet-generated hydrated electrons (eaq-). The rate and extent of PFECA degradation depend on both the branching extent and the chain length of oxygen-segregated fluoroalkyl moieties. Kinetic measurements, theoretical calculations, and transformation product analyses provide a comprehensive understanding of the PFECA degradation mechanisms and pathways. In comparison to traditional full-carbon-chain perfluorocarboxylic acids, the distinct degradation behavior of PFECAs is attributed to their ether structures. The ether oxygen atoms increase the bond dissociation energy of the C-F bonds on the adjacent -CF2- moieties. This impact reduces the formation of H/F-exchanged polyfluorinated products that are recalcitrant to reductive defluorination. Instead, the cleavage of ether C-O bonds generates unstable perfluoroalcohols and thus promotes deep defluorination of short fluoroalkyl moieties. In comparison to linear PFECAs, branched PFECAs have a higher tendency of H/F exchange on the tertiary carbon and thus lower percentages of defluorination. These findings provide mechanistic insights for an improved design and efficient degradation of fluorochemicals.
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Affiliation(s)
- Michael J Bentel
- Department of Chemical & Environmental Engineering , University of California, Riverside , Riverside , California 92521 , United States
| | - Yaochun Yu
- Department of Civil & Environmental Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Lihua Xu
- Department of Chemical & Environmental Engineering , University of California, Riverside , Riverside , California 92521 , United States
| | - Hyuna Kwon
- Department of Chemical & Environmental Engineering , University of California, Riverside , Riverside , California 92521 , United States
| | - Zhong Li
- Metabolomics Lab of Roy J. Carver Biotechnology Center , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Bryan M Wong
- Department of Chemical & Environmental Engineering , University of California, Riverside , Riverside , California 92521 , United States
- Materials Science & Engineering Program , University of California, Riverside , Riverside , California 92521 , United States
| | - Yujie Men
- Department of Chemical & Environmental Engineering , University of California, Riverside , Riverside , California 92521 , United States
- Department of Civil & Environmental Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Institute for Genomic Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Jinyong Liu
- Department of Chemical & Environmental Engineering , University of California, Riverside , Riverside , California 92521 , United States
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