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Stults JF, Schaefer CE, Fang Y, Devon J, Nguyen D, Real I, Hao S, Guelfo JL. Air-water interfacial collapse and rate-limited solid desorption control Perfluoroalkyl acid leaching from the vadose zone. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 265:104382. [PMID: 38861839 DOI: 10.1016/j.jconhyd.2024.104382] [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: 01/31/2024] [Revised: 05/08/2024] [Accepted: 06/02/2024] [Indexed: 06/13/2024]
Abstract
Some Per- and polyfluoroalkyl substances (PFAS) are strongly retained in the vadose zone due to their sorption to both soils and air-water interfaces. While significant research has been dedicated to understanding equilibrium behavior for these multi-phase retention processes, leaching and desorption from aqueous film-forming foam (AFFF) impacted soils under field relevant conditions can exhibit significant deviations from equilibrium. Herein, laboratory column studies using field collected AFFF-impacted soils were employed to examine the leaching of perfluoroalkyl acids (PFAAs) under simulated rainfall conditions. The HYDRUS 1-D model was calibrated to estimate the unsaturated hydraulic properties of the soil in a layered system using multiple boundary condtions. Forward simulations of equilibrium PFAS partitioning using the HYDRUS model and simplified mass balance calculations showed good agreement with the net PFAS mass flux out of the column. However, neither were able to predict the PFAS concentrations in the leached porewater. To better understand the mechanisms controlling the leaching behavior, the HYDRUS 1-D two-site leaching model incorporating solid phase rate limitation and equilibrium air-water interfacial partitioning was employed. Three variations of the novel model incorporating different forms of equilibrium air-water interfacial partitioning were considered using built-in numerical inversion. Results of numerical inversion show that a combination of air-water interfacial collapse and rate-limited desorption from soils can better predict the unique leaching behavior exhibited by PFAAs in AFFF-impacted soils. A sensitivity analysis of the initial conditions and rate-limited desorption terms was conducted to assess the agreement of the model with measured data. The models demonstrated herein show that, under some circumstances, laboratory equilibrium partitioning data can provide a reasonable estimation of total mass leaching, but fail to account for the significant rate-limited, non-Fickian transport which affect PFAA leaching to groundwater in unsaturated soils.
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Affiliation(s)
- John F Stults
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States.
| | - Charles E Schaefer
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States; CDM Smith, 110 Fieldcrest Avenue, #8, 6th Floor, Edison, NJ 08837, United States
| | - Yida Fang
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States; Haley and Aldrich Inc., 3131 Elliott Ave #600, Seattle, WA 98121, United States
| | - Julie Devon
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States
| | - Dung Nguyen
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States
| | - Isreq Real
- Civil, Environmental, and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Shilai Hao
- Civil & Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Jennifer L Guelfo
- Civil, Environmental, and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
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2
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Saha B, Ateia M, Fernando S, Xu J, DeSutter T, Iskander SM. PFAS occurrence and distribution in yard waste compost indicate potential volatile loss, downward migration, and transformation. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2024; 26:657-666. [PMID: 38312055 DOI: 10.1039/d3em00538k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
We discovered high concentrations of PFAS (18.53 ± 1.5 μg kg-1) in yard waste compost, a compost type widely acceptable to the public. Seventeen out of forty targeted PFAS, belonging to six PFAS classes were detected in yard waste compost, with PFCAs (13.51 ± 0.99 μg kg-1) and PFSAs (4.13 ± 0.19 μg kg-1) being the dominant classes, comprising approximately 72.5% and 22.1% of the total measured PFAS. Both short-chain PFAS, such as PFBA, PFHxA, and PFBS, and long-chain PFAS, such as PFOA and PFOS, were prevalent in all the tested yard waste compost samples. We also discovered the co-occurrence of PFAS with low-density polyethylene (LDPE) and polyethylene terephthalate (PET) plastics. Total PFAS concentrations in LDPE and PET separated from incoming yard waste were 7.41 ± 0.41 μg kg-1 and 1.35 ± 0.1 μg kg-1, which increased to 8.66 ± 0.81 μg kg-1 in LDPE and 5.44 ± 0.56 μg kg-1 in PET separated from compost. An idle mature compost pile revealed a clear vertical distribution of PFAS, with the total PFAS concentrations at the surface level approximately 58.9-63.2% lower than the 2 ft level. This difference might be attributed to the volatile loss of short-chain PFCAs, PFAS's downward movement with moisture, and aerobic transformations of precursor PFAS at the surface.
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Affiliation(s)
- Biraj Saha
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, 1410 14th Ave N, CIE 201, Fargo, North Dakota 58102, USA.
| | - Mohamed Ateia
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
| | - Sujan Fernando
- Department of Civil and Environmental Engineering, Clarkson University, Potsdam, New York 13699, USA
| | - Jiale Xu
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, 1410 14th Ave N, CIE 201, Fargo, North Dakota 58102, USA.
| | - Thomas DeSutter
- Department of Soil Science, North Dakota State University, Fargo, North Dakota 58108, USA
| | - Syeed Md Iskander
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, 1410 14th Ave N, CIE 201, Fargo, North Dakota 58102, USA.
- Environmental and Conservation Sciences, North Dakota State University, 1410 14th Ave N, CIE 201, Fargo, North Dakota 58108, USA
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Pan Y, Helbling DE. Revealing the factors resulting in incomplete recovery of perfluoroalkyl acids (PFAAs) when implementing the adsorbable and extractable organic fluorine methods. WATER RESEARCH 2023; 244:120497. [PMID: 37619306 DOI: 10.1016/j.watres.2023.120497] [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] [Received: 05/18/2023] [Revised: 07/24/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023]
Abstract
Per- and polyfluoroalkyl substances (PFASs) are environmental contaminants of concern. Techniques that quantify total organic fluorine (TOF) such as the adsorbable organic fluorine (AOF) and extractable organic fluorine (EOF) methods are important for PFAS risk assessments. The objective of this study was to systematically evaluate each step of the AOF (loading, washing, combustion) and EOF (loading, washing, elution, combustion) methods for the recovery of ten ultrashort-, short-, and long-chain unsubstituted perfluoroalkyl acids (PFAAs). We measured the overall recovery of fluoride for each method for each PFAA, and the recovery of each PFAA around the loading, washing, and elution steps. We also measured the combustion efficiency of each PFAA by direct combustion. The overall AOF and EOF recovery ranged from 9.3%-103.3% to 21.0%-108.1%, respectively, with higher recoveries measured for PFAAs with increasing chain length in both methods. The three ultrashort-chain PFAAs (trifluoroacetic acid, perfluoropropionic acid, and perfluoropropanesulfonic acid) exhibited the lowest overall recoveries from 9.3-25.2% for AOF and 21.0-51.5% for EOF. We found that decreases in the overall recovery are the result of losses of ultrashort- and short-chain PFAAs during the washing step and the incomplete mineralization of perfluoroalkyl sulfonic acids during combustion for AOF and incomplete elution of short- and long-chain PFAAs and the loss of ultrashort-chain PFAAs during the washing step for EOF. Our data suggest that the EOF method is more appropriate than the AOF method for measuring TOF in samples containing ultrashort- and short-chain PFAAs and that methodological improvements are possible with a focus on the washing, elution, and combustion steps.
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Affiliation(s)
- Yitong Pan
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Damian E Helbling
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA.
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Vitale DS, Reeves DM, Coffin ES, Link GW, Cassidy DP, Rochow SM. Long-duration monitoring and mass balance of PFAS at a wastewater treatment plant following the release of aqueous film-forming foam concentrate. WATER RESEARCH 2023; 242:120268. [PMID: 37390657 DOI: 10.1016/j.watres.2023.120268] [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: 04/20/2023] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 07/02/2023]
Abstract
Approximately 760 liters (200 gallons) of first-generation, PFOS-dominant, Aqueous Film-Forming Foam (AFFF) concentrate entered the sanitary sewer after an accidental release at the Kalamazoo/Battle Creek International Airport and migrated 11.4 km to the Kalamazoo Water Reclamation Plant. Near-daily sampling of influent, effluent, and biosolids generated a high-frequency, long-duration dataset used to understand the transport and fate of accidental PFAS releases to wastewater treatment plants, identify AFFF concentrate composition, and perform a plant-wide PFOS mass balance. Monitored influent concentrations exhibited sharp PFOS declines after 7 days post-spill, yet effluent discharges remained elevated due to return activated sludge (RAS) recirculation, resulting in the exceedance of Michigan's Surface Water Quality Value for 46 days. Mass balance estimates indicate 1.292 kg PFOS entering the plant and 1.368 kg leaving. Effluent discharge and sorption to biosolids account for 55% and 45% of estimated PFOS outputs, respectively. Identification of AFFF formulation and reasonable agreement between computed influent mass and reported spill volume demonstrates effective isolation of the AFFF spill signal and increases confidence in the mass balance estimates. These findings and related considerations provide critical insight for performing PFAS mass balances and developing operational procedures for accidental spills that minimize PFAS releases to the environment.
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Affiliation(s)
- Donovan S Vitale
- Department of Geological and Environmental Sciences, Western Michigan University, 1903W. Michigan Ave, Kalamazoo, MI 49008-5241, USA
| | - Donald M Reeves
- Department of Geological and Environmental Sciences, Western Michigan University, 1903W. Michigan Ave, Kalamazoo, MI 49008-5241, USA.
| | - Ethan S Coffin
- Department of Geological and Environmental Sciences, Western Michigan University, 1903W. Michigan Ave, Kalamazoo, MI 49008-5241, USA
| | - Garrett W Link
- Department of Geological and Environmental Sciences, Western Michigan University, 1903W. Michigan Ave, Kalamazoo, MI 49008-5241, USA
| | - Daniel P Cassidy
- Department of Geological and Environmental Sciences, Western Michigan University, 1903W. Michigan Ave, Kalamazoo, MI 49008-5241, USA
| | - Steven M Rochow
- Department of Public Service, City of Kalamazoo, 1415 Harrison Street, Kalamazoo, MI 49007, USA
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Li H, Dong Q, Zhang M, Gong T, Zan R, Wang W. Transport behavior difference and transport model of long- and short-chain per- and polyfluoroalkyl substances in underground environmental media: A review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 327:121579. [PMID: 37028785 DOI: 10.1016/j.envpol.2023.121579] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/13/2023] [Accepted: 04/03/2023] [Indexed: 06/19/2023]
Abstract
Perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFSAs), which are the most commonly regulated and most widely concerned per- and polyfluoroalkyl substances (PFAS) have received increasing attention on a global scale due to their amphiphilicity, stability, and long-range transport. Thus, understanding the typical PFAS transport behavior and using models to predict the evolution of PFAS contamination plumes is important for evaluating the potential risks. In this study, the effects of organic matter (OM), minerals, water saturation, and solution chemistry on the transport and retention of PFAS were investigated, and the interaction mechanism between long-chain/short-chain PFAS and the surrounding environment was analyzed. The results revealed that high content of OM/minerals, low saturation, low pH, and divalent cation had a great retardation effect on long-chain PFAS transport. The retention caused by hydrophobic interaction was the prominent mechanism for long-chain PFAS, whereas, the retention caused by electrostatic interaction was more relevant for short-chain PFAS. Additional adsorption at the air-water and nonaqueous-phase liquids (NAPL)-water interface was another potential interaction for retarding PFAS transport in the unsaturated media, which preferred to retard long-chain PFAS. Furthermore, the developing models for describing PFAS transport were investigated and summarized in detail, including the convection-dispersion equation, two-site model (TSM), continuous-distribution multi-rate model, modified-TSM, multi-process mass-transfer (MPMT) model, MPMT-1D model, MPMT-3D model, tempered one-sided stable density transport model, and a comprehensive compartment model. The research revealed PFAS transport mechanisms and provided the model tools, which supported the theoretical basis for the practical prediction of the evolution of PFAS contamination plumes.
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Affiliation(s)
- Hui Li
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China
| | - Qianling Dong
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China
| | - Meng Zhang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China
| | - Tiantian Gong
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China
| | - Rixia Zan
- School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Wenbing Wang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China.
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Huang YR, Liu SS, Zi JX, Cheng SM, Li J, Ying GG, Chen CE. In Situ Insight into the Availability and Desorption Kinetics of Per- and Polyfluoroalkyl Substances in Soils with Diffusive Gradients in Thin Films. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7809-7817. [PMID: 37155686 DOI: 10.1021/acs.est.2c09348] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The physicochemical exchange dynamics between the solid and solution phases of per- and polyfluoroalkyl substances (PFAS) in soils needs to be better understood. This study employed an in situ tool, diffusive gradients in thin films (DGT), to understand the distribution and exchange kinetics of five typical PFAS in four soils. Results show a nonlinear relationship between the PFAS masses in DGT and time, implying that PFAS were partially supplied by the solid phase in all of the soils. A dynamic model DGT-induced fluxes in soils/sediments (DIFS) was used to interpret the results and derive the distribution coefficients for the labile fraction (Kdl), response time (tc), and adsorption/desorption rates (k1 and k-1). The larger labile pool size (indicated by Kdl) for the longer chain PFAS implies their higher potential availability. The shorter chain PFAS tend to have a larger tc and relatively smaller k-1, implying that the release of these PFAS in soils might be kinetically limited but not for more hydrophobic compounds, such as perfluorooctanesulfonic acid (PFOS), although soil properties might play an important role. Kdl ultimately controls the PFAS availability in soils, while the PFAS release from soils might be kinetically constrained (which may also hold for biota uptake), particularly for more hydrophilic PFAS.
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Affiliation(s)
- Yue-Rui Huang
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Si-Si Liu
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Jin-Xin Zi
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Sheng-Ming Cheng
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Jun Li
- State Key Laboratory of Organic Geochemistry and Guangdong Province Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640, People's Republic of China
| | - Guang-Guo Ying
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Chang-Er Chen
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
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7
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Stults JF, Choi YJ, Rockwell C, Schaefer CE, Nguyen DD, Knappe DRU, Illangasekare TH, Higgins CP. Predicting Concentration- and Ionic-Strength-Dependent Air-Water Interfacial Partitioning Parameters of PFASs Using Quantitative Structure-Property Relationships (QSPRs). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5203-5215. [PMID: 36962006 DOI: 10.1021/acs.est.2c07316] [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] [Indexed: 06/18/2023]
Abstract
Air-water interfacial retention of poly- and perfluoroalkyl substances (PFASs) is increasingly recognized as an important environmental process. Herein, column transport experiments were used to measure air-water interfacial partitioning values for several perfluoroalkyl ethers and for PFASs derived from aqueous film-forming foam, while batch experiments were used to determine equilibrium Kia data for compounds exhibiting evidence of rate-limited partitioning. Experimental results suggest a Freundlich isotherm best describes PFAS air-water partitioning at environmentally relevant concentrations (101-106 ng/L). A multiparameter regression analysis for Kia prediction was performed for the 15 PFASs for which equilibrium Kia values were determined, assessing 246 possible combinations of 8 physicochemical and system properties. Quantitative structure-property relationships (QSPRs) based on three to four parameters provided predictions of high accuracy without model overparameterization. Two QSPRs (R2 values of 0.92 and 0.83) were developed using an assumed average Freundlich n value of 0.65 and validated across a range of relevant concentrations for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and hexafluoropropylene oxide-dimer acid (i.e., GenX). A mass action model was further modified to account for the changing ionic strength on PFAS air-water interfacial sorption. The final result was two distinct QSPRs for estimating PFAS air-water interfacial partitioning across a range of aqueous concentrations and ionic strengths.
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Affiliation(s)
- John F Stults
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
- CDM Smith, 14432 SE Eastgate Way Suite 100, Bellevue, Washington 98007, United States
| | - Youn Jeong Choi
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Cooper Rockwell
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Charles E Schaefer
- CDM Smith, 110 Fieldcrest Avenue, #8, 6th Floor, Edison, Edison, New Jersey 08837, United States
| | - Dung D Nguyen
- CDM Smith, 14432 SE Eastgate Way Suite 100, Bellevue, Washington 98007, United States
| | - Detlef R U Knappe
- Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Tissa H Illangasekare
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Christopher P Higgins
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
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Lei X, Lian Q, Zhang X, Karsili TK, Holmes W, Chen Y, Zappi ME, Gang DD. A review of PFAS adsorption from aqueous solutions: Current approaches, engineering applications, challenges, and opportunities. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 321:121138. [PMID: 36702432 DOI: 10.1016/j.envpol.2023.121138] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 01/17/2023] [Accepted: 01/21/2023] [Indexed: 06/18/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) have drawn great attention due to their wide distribution in water bodies and toxicity to human beings. Adsorption is considered as an efficient treatment technique for meeting the increasingly stringent environmental and health standards for PFAS. This paper systematically reviewed the current approaches of PFAS adsorption using different adsorbents from drinking water as well as synthetic and real wastewater. Adsorbents with large mesopores and high specific surface area adsorb PFAS faster, their adsorption capacities are higher, and the adsorption process are usually more effective under low pH conditions. PFAS adsorption mechanisms mainly include electrostatic attraction, hydrophobic interaction, anion exchange, and ligand exchange. Various adsorbents show promising performances but challenges such as requirements of organic solvents in regeneration, low adsorption selectivity, and complicated adsorbent preparations should be addressed before large scale implementation. Moreover, the aid of decision-making tools including response surface methodology (RSM), techno-economic assessment (TEA), life cycle assessment (LCA), and multi criteria decision analysis (MCDA) were discussed for engineering applications. The use of these tools is highly recommended prior to scale-up to determine if the specific adsorption process is economically feasible and sustainable. This critical review presented insights into the most fundamental aspects of PFAS adsorption that would be helpful to the development of effective adsorbents for the removal of PFAS in future studies and provide opportunities for large-scale engineering applications.
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Affiliation(s)
- Xiaobo Lei
- Department of Civil Engineering, University of Louisiana at Lafayette, Lafayette, LA 70504, USA; Center for Environmental Technology, The Energy Institute of Louisiana, University of Louisiana at Lafayette, P. O. Box 43597, Lafayette, LA, 70504, USA
| | - Qiyu Lian
- Department of Civil Engineering, University of Louisiana at Lafayette, Lafayette, LA 70504, USA; Center for Environmental Technology, The Energy Institute of Louisiana, University of Louisiana at Lafayette, P. O. Box 43597, Lafayette, LA, 70504, USA
| | - Xu Zhang
- Department of Civil Engineering, University of Louisiana at Lafayette, Lafayette, LA 70504, USA; Beijing International Scientific and Technological Cooperation Base of Water Pollution Control Techniques for Antibiotics and Resistance Genes, School of Civil Engineering, Beijing Jiaotong University, 3 Shangyuancun, Beijing 100044, PR China
| | - Tolga K Karsili
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA 70504, USA
| | - William Holmes
- Center for Environmental Technology, The Energy Institute of Louisiana, University of Louisiana at Lafayette, P. O. Box 43597, Lafayette, LA, 70504, USA; Department of Chemical Engineering, University of Louisiana at Lafayette, Lafayette, LA 70504, USA
| | - Yushun Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, PR China
| | - Mark E Zappi
- Center for Environmental Technology, The Energy Institute of Louisiana, University of Louisiana at Lafayette, P. O. Box 43597, Lafayette, LA, 70504, USA; Department of Chemical Engineering, University of Louisiana at Lafayette, Lafayette, LA 70504, USA
| | - Daniel Dianchen Gang
- Department of Civil Engineering, University of Louisiana at Lafayette, Lafayette, LA 70504, USA; Center for Environmental Technology, The Energy Institute of Louisiana, University of Louisiana at Lafayette, P. O. Box 43597, Lafayette, LA, 70504, USA.
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Stults JF, Choi YJ, Schaefer CE, Illangasekare TH, Higgins CP. Estimation of Transport Parameters of Perfluoroalkyl Acids (PFAAs) in Unsaturated Porous Media: Critical Experimental and Modeling Improvements. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7963-7975. [PMID: 35549168 DOI: 10.1021/acs.est.2c00819] [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] [Indexed: 06/15/2023]
Abstract
Predicting the transport of perfluoroalkyl acids (PFAAs) in the vadose zone is critically important for PFAA site cleanup and risk mitigation. PFAAs exhibit several unusual and poorly understood transport behaviors, including partitioning to the air-water interface, which is currently the subject of debate. This study develops a novel use of quasi-saturated (residual air saturation) column experiments to estimate chemical partitioning parameters of both linear and branched perfluorooctane sulfonate (PFOS) in unsaturated soils. The ratio of linear-to-branched air-water interfacial partitioning constants for all six experiments was 1.62 ± 0.24, indicating significantly greater partitioning of linear PFOS isomers at the air-water interface. Standard breakthrough curve analysis and numerical inversion of HYDRUS models support the application of a Freundlich isotherm for PFOS air-water interfacial partitioning below a critical reference concentration (CRC). Data from this study and previously reported unsaturated column data on perfluorooctanoate (PFOA) were reevaluated to examine unsaturated systems for transport nonidealities. This reanalysis suggests both transport nonidealities and Freundlich isotherm behavior for PFOA below the CRC using drainage-based column methods, contrary to the assertions of the original authors. Finally, a combined Freundlich-Langmuir isotherm was proposed to describe PFAA air-water interfacial partitioning across the full range of relevant PFAA concentrations.
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Affiliation(s)
- John F Stults
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 3557, United States
| | - Youn Jeong Choi
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 3557, United States
| | - Charles E Schaefer
- CDM Smith, 110 Fieldcrest Avenue, #8, 6th Floor, Edison, New Jersey 08837, United States
| | - Tissa H Illangasekare
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 3557, United States
| | - Christopher P Higgins
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 3557, United States
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Fabrication of the Ordered Mesoporous nZVI/Zr-Ce-SBA-15 Composites Used for Crystal Violet Removal and Their Optimization Using RSM and ANN–PSO. SUSTAINABILITY 2022. [DOI: 10.3390/su14116566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Crystal violet (CV), a triphenylmethane dye, is widely used in the textile, printing, paper, leather, and cosmetics industries. However, due to its higher chemical stability and lower biodegradability, CV has teratogenic and carcinogenic toxic effects on animals and humans. Therefore, the objective of the present study was to investigate whether or not the as-prepared nZVI supported on an ordered mesoporous Zr-Ce-SBA-15 composite (nZVI/Zr-Ce-SBA-15) had more potential for CV removal from simulated wastewater in comparison with Zr-Ce-SBA-15. Meanwhile, the parameters of CV adsorption onto nZVI/Zr-Ce-SBA-15 composites were optimized by a response surface methodology (RSM) and an artificial neural network combined with particle swarm optimization (ANN–PSO). According to XRD, FTIR, SEM, and TEM, N2 adsorption, and thermogravimetric analyses, nZVI was supported successfully on Zr-Ce-SBA-15 composites, becoming an ordered mesoporous material. The results of RSM indicated that the order of the effects of the four parameters on CV removal was, successively, initial pH, contact time, temperature, and initial CV concentration. ANN–PSO was more suitable, in comparison to RSM, to optimize the experimental parameters for CV removal from simulated wastewater using ordered mesoporous nZVI/Zr-Ce-SBA-15 composites. The optimized removal rate of CV was 93.87% under an initial pH of 3.00, a contact time of 20.00 min, an initial CV concentration of 261.00 mg/L, and a temperature of 45. Pseudo-second-order kinetics can better describe the behavior of CV adsorption onto nZVI/Zr-Ce-SBA-15 composites. The process of CV adsorption onto Zr-Ce-SBA-15 composites was followed by the Langmuir model, and its maximum adsorption capacity was 105 mg/g in 213 K. It was indirectly confirmed that the maximum adsorption capacity of nZVI/Zr-Ce-SBA-15 exceeded this value because the removal efficiency of CV using nZVI/Zr-Ce-SBA-15 was obviously higher than that of using Zr-Ce-SBA-15. The thermodynamics results indicated that CV adsorption onto nZVI/Zr-Ce-SBA-15 was a spontaneous, endothermic, and entropy-driven process. The dissolution of Fe ions and light/dark experiments confirmed nZVI/Zr-Ce-SBA-15 was simultaneously of adsorption and catalysis in the process of CV removal. The effect of removal CV was still maintained in the first four experiments (removal rate > 78%), and our suggestion is that nZVI/Zr-Ce-SBA-15 is a potential adsorbent for CV remediation from wastewater compared to Zr-Ce-SBA-15 and other adsorbents.
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Zhang Q, Wu X, Lyu X, Gao B, Wu J, Sun Y. Effects of anionic hydrocarbon surfactant on the transport of perfluorooctanoic acid (PFOA) in natural soils. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:24672-24681. [PMID: 34826077 DOI: 10.1007/s11356-021-17680-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/18/2021] [Indexed: 06/13/2023]
Abstract
The widespread usage of per- and polyfluoroalkyl substances (PFASs) has led to their ubiquitous co-existence with hydrocarbon surfactants in the subsurface environment. In this study, column experiments were conducted to investigate the effect of an anionic hydrocarbon surfactant (sodium dodecylbenzene sulfonate, SDBS, 1 and 10 mg/L) on the transport of perfluorooctanoic acid (PFOA) in two saturated natural soils under different cation type (Na+ and Ca2+) conditions. Results showed that SDBS (10 mg/L) significantly enhanced the transport of PFOA in two soils. This was likely because SDBS had a stronger adsorption affinity to the soils than PFOA, and can outcompete PFOA for the finite adsorption sites on the soil surface. The effect of SDBS on PFOA transport varied greatly in the two soils. More negatively charged soil surface and greater soil particle size likely contributed to the more noticeable transport-enhancement of PFOA resulting from the presence of SDBS. Also, the enhancement effect of SDBS (10 mg/L) with Ca2+ on PFOA transport was more significantly than that with Na+. This was possibly due to the blocking effect of SDBS to the more positively charged soil surface induced by Ca2+. Findings of this study point out the importance of anionic hydrocarbon surfactants on PFOA transport when assessing its environmental risks and implementing remediation efforts.
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Affiliation(s)
- Qi Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing, 210023, China
| | - Xiaoli Wu
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing, 210023, China
| | - Xueyan Lyu
- School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
| | - Bin Gao
- Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Jichun Wu
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing, 210023, China
| | - Yuanyuan Sun
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing, 210023, China.
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Gefell MJ, Huang H, Opdyke D, Gustafson K, Vlassopoulos D, McCray JE, Best S, Carey M. Modeling PFAS Fate and Transport in Groundwater, with and Without Precursor Transformation. GROUND WATER 2022; 60:6-14. [PMID: 34850384 DOI: 10.1111/gwat.13152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 06/13/2023]
Abstract
Groundwater professionals require tools to evaluate a variety of technical issues related to per- and polyfluoroalkyl substances (PFAS). These include the potential impact of PFAS precursors on groundwater plumes of perfluoroalkyl acids (PFAAs). Numerical modeling results show that, by adjusting the mass loading rate, source zones with or without a precursor can produce similar PFAA plumes. However, if a precursor is present, it can impact PFAA plume concentrations and extend PFAA plume durations by decades. Additional research regarding in situ precursor transformation rates-and improvements in source area characterization-will further advance the predictive value of modeling.
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Affiliation(s)
| | - Hai Huang
- Anchor QEA, LLC, Portland, OR, 97219, USA
| | | | | | | | - John E McCray
- Department of Civil & Environmental Engineering, Hydrologic Science and Engineering Program, Colorado School of Mines, Golden, CO, 80401, USA
| | - Sam Best
- Anchor QEA, LLC, New Orleans, LA, 70124, USA
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Brusseau ML, Guo B, Huang D, Yan N, Lyu Y. Ideal versus Nonideal Transport of PFAS in Unsaturated Porous Media. WATER RESEARCH 2021; 202:117405. [PMID: 34273774 PMCID: PMC8559529 DOI: 10.1016/j.watres.2021.117405] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 06/23/2021] [Accepted: 06/30/2021] [Indexed: 05/11/2023]
Abstract
Per- and poly-fluoroalkyl substances (PFAS) adsorb at air-water interfaces during transport in unsaturated porous media. This can cause surfactant-induced flow and enhanced retention that is a function of concentration, which complicates characterization and modeling of PFAS transport under unsaturated conditions. The influence of surfactant-induced flow and nonlinear air-water interfacial adsorption (AWIA) on PFAS transport was investigated with a series of miscible-displacement transport experiments conducted with a several-log range in input concentrations. Perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and ammonium perfluoro 2-methyl-3-oxahexanoate (GenX) were used as model PFAS. The results were interpreted in terms of critical reference concentrations associated with PFAS surface activities and their relationship to the relevancy of transport processes such as surfactant-induced flow and nonlinear AWIA for concentration ranges of interest. Analysis of the measured transport behavior of PFAS under unsaturated-flow conditions demonstrated that AWIA was linear when the input concentration was sufficiently below the critical reference concentration. This includes the absence of significant arrival-front self-sharpening and extended elution tailing of the breakthrough curves, as well as the similarity of retardation factors measured for a wide range of input concentrations. Independently-predicted simulations produced with a comprehensive flow and transport model that accounts for transient variably-saturated flow, surfactant-induced flow, nonlinear rate-limited solid-phase sorption, and nonlinear rate-limited AWIA provided excellent predictions of the measured transport. A series of simulations was conducted with the model to test the specific impact of various processes potentially influencing PFOS transport. The simulation results showed that surfactant-induced flow was negligible and that AWIA was effectively linear when the input concentration was sufficiently below the critical reference concentration. PFAS retention associated with AWIA can be considered to be ideal in such cases, thereby supporting the use of simplified mathematical models. Conversely, apparent nonideal transport behavior was observed for experiments conducted with input concentrations similar to or greater than the critical reference concentration.
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Affiliation(s)
- Mark L Brusseau
- Environmental Science Department, University of Arizona, Tucson, AZ, USA; Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA.
| | - Bo Guo
- Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
| | - Dandan Huang
- Environmental Science Department, University of Arizona, Tucson, AZ, USA; School of Water Resources & Environment, China University of Geosciences, Beijing 100083, P.R. China
| | - Ni Yan
- Environmental Science Department, University of Arizona, Tucson, AZ, USA; Key Lab of Marine Environmental Science and Ecology, College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, P.R. China
| | - Ying Lyu
- Environmental Science Department, University of Arizona, Tucson, AZ, USA; Key Lab of Groundwater Resources and Environment, Jilin Provincial Key Laboratory of Water Resources and Environment, and Institute of Water Resources and Environment, Jilin University, Changchun, 130026, PR China
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