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Chen D, Hu X, Chen C, Gao Y, Zhou Q, Feng X, Xu X, Lin D, Xu J. Impacts of Perfluoroalkyl Substances on Aqueous and Nonaqueous Phase Liquid Dechlorination by Sulfidized Nanoscale Zerovalent Iron. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:11193-11202. [PMID: 38859757 DOI: 10.1021/acs.est.4c04466] [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: 06/12/2024]
Abstract
Per- and poly fluoroalkyl substances (PFASs) are often encountered with nonaqueous phase liquid (NAPL) in the groundwater at fire-fighting and military training sites. However, it is unclear how PFASs affect the dechlorination performance of sulfidized nanoscale zerovalent iron (S-nFe0), which is an emerging promising NAPL remediation agent. Here, S-nFe0 synthesized with controllable S speciation (FeS or FeS2) were characterized to assess their interactions with PFASs and their dechlorination performance for trichloroethylene NAPL (TCE-NAPL). Surface-adsorbed PFASs blocked materials' reactive sites and inhibited aqueous TCE dechlorination. In contrast, PFASs-adsorbed particles with improved hydrophobicity tended to enrich at the NAPL-water interface, and the reactive sites were re-exposed after the PFASs accumulation into the NAPL phase to accelerate dechlorination. This PFASs-induced phenomenon allowed the materials to present a higher reactivity (up to 1.8-fold) with a high electron efficiency (up to 99%) for TCE-NAPL dechlorination. Moreover, nFe0-FeS2 with a higher hydrophobicity was more readily enriched at the NAPL-water interface and more reactive and selective than nFe0-FeS, regardless of coexisting PFASs. These results unveil that a small amount of yet previously overlooked coexisting PFASs can favor selective reductions of TCE-NAPL by S-nFe0, highlighting the importance of materials hydrophobicity and transportation induced by S and PFASs for NAPL remediation.
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Affiliation(s)
- Du Chen
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xiaohong Hu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chaohuang Chen
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yiman Gao
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Qianhai Zhou
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xia Feng
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xinhua Xu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Daohui Lin
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
| | - Jiang Xu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
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Arshadi M, Garza-Rubalcava U, Guedes A, Cápiro NL, Pennell KD, Christ J, Abriola LM. Modeling 1-D aqueous film forming foam transport through the vadose zone under realistic site and release conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170566. [PMID: 38331271 DOI: 10.1016/j.scitotenv.2024.170566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/12/2024] [Accepted: 01/28/2024] [Indexed: 02/10/2024]
Abstract
Aqueous film forming foams (AFFFs) have been used to extinguish fires since the 1960s, leading to widespread subsurface contamination by per- and polyfluoroalkyl substances (PFAS), an essential component of AFFF. This study presents 1-D simulations of PFAS migration in the vadose zone resulting from AFFF releases. Simulation scenarios used soil profiles from three US Air Force (USAF) installations, encompassing a range of climatic conditions and hydrogeologic environments. A three-component mixture, representative of major constituents of AFFF, facilitated the exploration of competitive and synergistic effects of co-constituents on PFAS migration. To accurately capture unsaturated transport of PFAS in porous media, the model considers (1) surfactant-induced flow, (2) non-linear sorption to the solid phase, (3) competitive accumulation at the air-water interface, and (4) the moisture-dependence of the air-water interfacial area. Defined PFAS releases were consistent with fire training exercises, emergency responses, and accidental spills of record. Simulation results illustrate the importance of hydrogeologic, climatic, geochemical, and AFFF release conditions on PFAS transport and retention. Comparison of field observations and model simulations for Ellsworth AFB indicate that much of the PFOA and PFOS mass is associated with the air-water interface and the solid phase, which limits their migration potential in the vadose zone. Results also show that rates of migration in the aqueous phase are largely controlled by hydrogeologic properties, including recharge rates and hydraulic conductivity. AFFF spill scenarios varying in volume, concentration, and frequency reveal the importance of release characteristics in determining rates of PFAS migration and concentration peaks. Variability is attributed to non-linear sorption processes, where, contrary to simple linear partitioning formulations, transport is strongly affected by the concentration of PFAS species. Simulations also demonstrate the importance of modeling the AFFF as a mixture since competitive interfacial accumulation effects are shown to enhance the mobility of less surface-active PFAS compounds.
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Affiliation(s)
- Masoud Arshadi
- Department of Civil and Environmental Engineering, Tufts University, Medford, MA 02155, United States
| | | | - Ana Guedes
- Department of Civil and Environmental Engineering, Tufts University, Medford, MA 02155, United States
| | - Natalie L Cápiro
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, United States
| | - Kurt D Pennell
- School of Engineering, Brown University, Providence, RI 02912, United States
| | - John Christ
- S&B Christ Consulting, Las Vegas, NV 89134, United States
| | - Linda M Abriola
- School of Engineering, Brown University, Providence, RI 02912, United States.
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Umeh AC, Naidu R, Olisa E, Liu Y, Qi F, Bekele D. A systematic investigation of single solute, binary and ternary PFAS transport in water-saturated soil using batch and 1-dimensional column studies: Focus on mixture effects. JOURNAL OF HAZARDOUS MATERIALS 2024; 461:132688. [PMID: 37797575 DOI: 10.1016/j.jhazmat.2023.132688] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/27/2023] [Accepted: 09/30/2023] [Indexed: 10/07/2023]
Abstract
This study aimed to investigate the transport and release of per- and polyfluoroalkyl substances (PFAS), as single solutes and binary and ternary mixtures, and associated competitive sorption effects in water-saturated soil. Batch sorption isotherm and desorption, and one-dimensional miscible displacement studies were conducted. For the batch study, the mixtures exhibited extensive sorption isotherm nonlinearity at aqueous concentrations exceeding 20 µg/L. At and above this threshold, competitive effects significantly decreased PFAS sorption, mostly affecting perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS). Importantly, mixture effects exacerbated isotherm nonlinearity and may increase the leaching of PFAS in subsurface soil and groundwater. Further, up to 100% desorption occurred for single solutes and mixtures, indicating that the studied PFAS were weakly sorbed. For the column study, at influent concentrations (21 - 27 µg/L, depending on PFAS) near the threshold, PFOA and PFHxS breakthrough curves (BTC) generally exhibited equilibrium (nonlinear) transport, whereas perfluorooctane sulfonate (PFOS) exhibited nonequilibrium transport, with minimal or no mixture effects. Nonequilibrium transport of PFOS was driven by rate-limited sorption, especially as flow interruption tests confirmed the absence of physical nonequilibrium. The sorption distribution coefficients (Kd) from moment and frontal analyses, and 2-site modelling of the BTC, were consistent with the batch-derived Kd, although comparatively smaller. Such discrepancies may limit the applicability of batch-derived Kd values for predictive transport modelling purposes. Overall, understanding mixture impacts may aid effective predictive modelling of PFAS transport and leaching, especially in aqueous film forming foam (AFFF)-source zone areas associated with elevated PFAS concentrations. At low or environmental PFAS concentrations, mixture effects can be expected to be play a minor role in influencing PFAS transport.
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Affiliation(s)
- Anthony C Umeh
- Global Centre for Environmental Remediation (GCER), The University of Newcastle, Callaghan, NSW 2308, Australia; crcCARE, The University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Ravi Naidu
- Global Centre for Environmental Remediation (GCER), The University of Newcastle, Callaghan, NSW 2308, Australia; crcCARE, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Emmanuel Olisa
- Global Centre for Environmental Remediation (GCER), The University of Newcastle, Callaghan, NSW 2308, Australia; Geosyntec Consultants, 211 Wheeler St, Saskatoon, SK S7P 0A4, Canada
| | - Yanju Liu
- Global Centre for Environmental Remediation (GCER), The University of Newcastle, Callaghan, NSW 2308, Australia; crcCARE, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Fangjie Qi
- Global Centre for Environmental Remediation (GCER), The University of Newcastle, Callaghan, NSW 2308, Australia; Nanjing Institute of Soil Science, Chinese Academy of Sciences, 71 Beijing East Road, Nanjing, Jiangsu Province 210008, China
| | - Dawit Bekele
- Global Centre for Environmental Remediation (GCER), The University of Newcastle, Callaghan, NSW 2308, Australia; Douglas Partners Pty Ltd, 439 Montague Road West End, QLD 4101, Australia
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Cai HY, Wu QY, Ouyang WY, Hu HY, Wang WL. Efficient removal of electroneutral carbonyls by combined vacuum-UV oxidation and anion-exchange resin adsorption: mechanism, model simulation, and optimization. WATER RESEARCH 2023; 243:120435. [PMID: 37536248 DOI: 10.1016/j.watres.2023.120435] [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: 06/06/2023] [Revised: 07/26/2023] [Accepted: 07/28/2023] [Indexed: 08/05/2023]
Abstract
Electroneutral carbonyls (ENCs) with low molecular weights (e.g., aldehydes and ketones) are recalcitrant to single water treatment process to achieve ultralow concentration. Residual ENCs are present in reverse osmosis permeate and pose risks to human health during potable use or industrial application in manufacturing processes. Herein, a combined vacuum-UV (VUV) oxidation and anion-exchange resin (AER) adsorption method was developed to treat the ENCs and reduce total organic carbon (TOC) to an ultralow concentration (< 5 μg/L) with high efficiency and at low cost. VUV-AER was 2.1-2.4 times more efficient than VUV alone for the removal of TOC. VUV oxidized the ENCs to electronegative carboxylic acids, which were adsorbed by the AER through electrostatic interactions and hydrogen bonding. When the VUV fluence was lower than 643 mJ cm-2, the AER could not achieve ultralow TOC removal of ENCs. The treat capacity of 1500-2900 valid bed volume (BVs) was achieved after increasing the VUV fluence to 1929 mJ cm-2. The AER could more efficiently adsorb carboxylic acids that contained more carboxylic groups or shorter carbon chain. Acetate was identified as the primary breakthrough product at relatively low VUV fluence, and oxalate was the main byproduct at relatively high VUV fluence. A mathematical model to predict TOC breakthrough was developed considering the VUV-oxidation kinetics and the AER breakthrough curve. The model was used to optimize the method to maximize TOC removal and minimize energy consumption. These results imply that VUV-AER is technically feasible and economically applicable to eliminate recalcitrant ENCs to ultralow concentration for the production of water requires high quality (e.g., potable water or electronic-grade ultrapure water).
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Affiliation(s)
- Han-Ying Cai
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Institute of Environment and Ecology, Tsinghua University, Shenzhen 518055, China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China
| | - Qian-Yuan Wu
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Institute of Environment and Ecology, Tsinghua University, Shenzhen 518055, China
| | - Wan-Yue Ouyang
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Institute of Environment and Ecology, Tsinghua University, Shenzhen 518055, China
| | - Hong-Ying Hu
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Institute of Environment and Ecology, Tsinghua University, Shenzhen 518055, China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China; Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Room 524, Beijing 100084, PR China
| | - Wen-Long Wang
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Institute of Environment and Ecology, Tsinghua University, Shenzhen 518055, China.
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Guo B, Saleem H, Brusseau ML. Predicting Interfacial Tension and Adsorption at Fluid-Fluid Interfaces for Mixtures of PFAS and/or Hydrocarbon Surfactants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:8044-8052. [PMID: 37204869 DOI: 10.1021/acs.est.2c08601] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Many per- and polyfluoroalkyl substances (PFAS) are surface-active and adsorb at fluid-fluid interfaces. The interfacial adsorption controls PFAS transport in multiple environmental systems, including leaching through soils, accumulation in aerosols, and treatment methods such as foam fractionation. Most PFAS contamination sites comprise mixtures of PFAS as well as hydrocarbon surfactants, which complicates their adsorption behaviors. We present a mathematical model for predicting interfacial tension and adsorption at fluid-fluid interfaces for multicomponent PFAS and hydrocarbon surfactants. The model is derived from simplifying a prior advanced thermodynamic-based model and applies to nonionic and ionic mixtures of the same charge sign with swamping electrolytes. The only required model inputs are the single-component Szyszkowski parameters obtained for the individual components. We validate the model using literature interfacial tension data of air-water and NAPL (non-aqueous phase liquid)-water interfaces covering a wide range of multicomponent PFAS and hydrocarbon surfactants. Application of the model to representative porewater PFAS concentrations in the vadose zone suggests competitive adsorption can significantly reduce PFAS retention (up to 7 times) at some highly contaminated sites. The multicomponent model can be readily incorporated into transport models to simulate the migration of mixtures of PFAS and/or hydrocarbon surfactants in the environment.
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Affiliation(s)
- Bo Guo
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, Arizona 85721, United States
| | - Hassan Saleem
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, Arizona 85721, United States
| | - Mark L Brusseau
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, Arizona 85721, United States
- Department of Environmental Science, University of Arizona, Tucson, Arizona 85719, United States
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