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Molé RA, Velosa AC, Carey GR, Liu X, Li G, Fan D, Danko A, Lowry GV. Groundwater solutes influence the adsorption of short-chain perfluoroalkyl acids (PFAA) to colloidal activated carbon and impact performance for in situ groundwater remediation. JOURNAL OF HAZARDOUS MATERIALS 2024; 474:134746. [PMID: 38850952 DOI: 10.1016/j.jhazmat.2024.134746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/21/2024] [Accepted: 05/26/2024] [Indexed: 06/10/2024]
Abstract
Subsurface injection of colloidal activated carbon (CAC) is an in situ remediation strategy for perfluoroalkyl acids (PFAA), but the influence of groundwater solutes on longevity is uncertain, particularly for short-chain PFAA. We quantify the impact of inorganic anions, dissolved organic matter (DOM), and stabilizing polymer on PFAA adsorption to a commercial CAC. Surface characterization supported PFAA chain-length dependent adsorption results and mechanisms are provided. Inorganic anions decreased adsorption for short-chain PFAA (<7 perfluorinated carbons) due to competitive effects, while long-chain PFAA (≥ 7 perfluorinated carbons) were less impacted. DOM decreased adsorption of all PFAA in a chain-length dependent manner. High DOM concentrations (10 mg/L, ∼5 mg OC/L) decreased PFOA adsorption by a factor of 2, PFPeA by one order of magnitude, and completely hindered PFBA adsorption. High MW DOM has less impact on short-chain PFAA than low MW DOM, possibly due to differences in the ability to access CAC micropores. Low DOM concentrations (1 mg/L, ∼0.5 mg OC/L) did not impact adsorption. CMC (90 kDa average MW) had negligible impact on PFAA adsorption likely due to minimal CAC surface coverage. Longevity modeling demonstrated that groundwater solutes limit the capacity for PFAA in a CAC barrier, particularly for short-chain PFAA.
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Affiliation(s)
- Rachel A Molé
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Adriana C Velosa
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Grant R Carey
- Porewater Solutions, 2958 Barlow Crescent, Ottawa, Ontario K0A 1T0, Canada
| | - Xitong Liu
- Department of Civil and Environmental Engineering, The George Washington University, Washington, DC 20052, USA
| | - Guangbin Li
- Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, 20742, USA
| | - Dimin Fan
- Geosyntec Consultants, 65 North Raymond Ave. Suite 200, Pasadena, CA 91103, USA
| | - Anthony Danko
- Naval Facilities Engineering Systems Command, Engineering and Expeditionary Warfare Center, Port Hueneme, CA, 93043, USA
| | - Gregory V Lowry
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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2
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Guan X, Kong L, Liu C, Fan D, Anger B, Johnson WP, Lowry GV, Li G, Danko A, Liu X. Polymer Coatings Affect Transport and Remobilization of Colloidal Activated Carbon in Saturated Sand Columns: Implications for In Situ Groundwater Remediation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:8531-8541. [PMID: 38690765 DOI: 10.1021/acs.est.3c08251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Colloidal activated carbon (CAC) is an emerging technology for the in situ remediation of groundwater impacted by per- and polyfluoroalkyl substances (PFAS). In assessing the long-term effectiveness of a CAC barrier, it is crucial to evaluate the potential of emplaced CAC particles to be remobilized and migrate away from the sorptive barrier. We examine the effect of two polymer stabilizers, carboxymethyl cellulose (CMC) and polydiallyldimethylammonium chloride (PolyDM), on CAC deposition and remobilization in saturated sand columns. CMC-modified CAC showed high mobility in a wide ionic strength (IS) range from 0.1 to 100 mM, which is favorable for CAC delivery at a sufficient scale. Interestingly, the mobility of PolyDM-modified CAC was high at low IS (0.1 mM) but greatly reduced at high IS (100 mM). Notably, significant remobilization (release) of deposited CMC-CAC particles occurred upon the introduction of solution with low IS following deposition at high IS. In contrast, PolyDM-CAC did not undergo any remobilization following deposition due to its favorable interactions with the quartz sand. We further elucidated the CAC deposition and remobilization behaviors by analyzing colloid-collector interactions through the application of Derjaguin-Landau-Verwey-Overbeek theory, and the inclusion of a discrete representation of charge heterogeneity on the quartz sand surface. The classical colloid filtration theory was also employed to estimate the travel distance of CAC in saturated columns. Our results underscore the roles of polymer coatings and solution chemistry in CAC transport, providing valuable guidelines for the design of in situ CAC remediation with maximized delivery efficiency and barrier longevity.
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Affiliation(s)
- Xun Guan
- Department of Civil & Environmental Engineering, George Washington University, 800 22nd Street, Washington, Washington D.C. 20052, United States
| | - Lingchen Kong
- Department of Civil & Environmental Engineering, George Washington University, 800 22nd Street, Washington, Washington D.C. 20052, United States
| | - Chenwei Liu
- Department of Civil & Environmental Engineering, George Washington University, 800 22nd Street, Washington, Washington D.C. 20052, United States
| | - Dimin Fan
- Geosyntec Consultants, Inc, 10211 Wincopin Circle, Fourth Floor, Columbia, Maryland 21044, United States
| | - Bridget Anger
- Department of Civil & Environmental Engineering, George Washington University, 800 22nd Street, Washington, Washington D.C. 20052, United States
| | - William P Johnson
- Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, United States
| | - Gregory V Lowry
- Department of Civil & Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Guangbin Li
- Department of Civil and Environmental Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Anthony Danko
- Naval Facilities Engineering Systems Command - Engineering and Expeditionary Warfare Center, Port Hueneme, California 93043, United States
| | - Xitong Liu
- Department of Civil & Environmental Engineering, George Washington University, 800 22nd Street, Washington, Washington D.C. 20052, United States
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3
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Ejaz M, Gul A, Ozturk M, Hafeez A, Turkyilmaz Unal B, Jan SU, Siddique MT. Nanotechnologies for environmental remediation and their ecotoxicological impacts. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:1368. [PMID: 37875634 DOI: 10.1007/s10661-023-11661-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 08/01/2023] [Indexed: 10/26/2023]
Abstract
Environmental nanoremediation is an emerging technology that aims to rapidly and efficiently remove contaminants from the polluted sites using engineered nanomaterials (ENMs). Inorganic nanoparticles which are generally metallic, silica-based, carbon-based, or polymeric in nature serve to remediate through chemical reactions, filtration, or adsorption. Their greater surface area per unit mass and high reactivity enable them to treat groundwater, wastewater, oilfields, and toxic industrial contaminants. Despite the growing interest in nanotechnological solutions for bioremediation, the environmental and human hazard associated with their use is raising concerns globally. Nanoremediation techniques when compared to conventional remediation solutions show increased effectivity in terms of cost and time; however, the main challenge is the ability of ENMs to remove contaminants from different environmental mediums by safeguarding the ecosystem. ENMs improving the accretion of the pollutant and increasing their bioavailability should be rectified along with the vigilant management of their transfer to the upper levels of the food chain which subsequently causes biomagnification. The ecosystem-centered approach will help monitor the ecotoxicological impacts of nanoremediation considering the safety, sustainability, and proper disposal of ENMs. The environment and human health risk assessment of each novel engineered nanomaterial along with the regulation of life cycle assessment (LCA) tools of ENMs for nanoremediation can help investigate the possible environmental hazard. This review focuses on the currently available nanotechnological methods used for environmental remediation and their potential toxicological impacts on the ecosystem.
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Affiliation(s)
- Mahnoor Ejaz
- Atta-Ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology, Islamabad, Pakistan
| | - Alvina Gul
- Atta-Ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology, Islamabad, Pakistan.
| | - Munir Ozturk
- Botany Department and Centre for Environmental Studies, Ege University, Izmir, Türkiye.
| | - Ahmed Hafeez
- Atta-Ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology, Islamabad, Pakistan
| | - Bengu Turkyilmaz Unal
- Biotechnology Department, Faculty of Arts and Science, Nigde Omer Halisdemir University, Nigde, Türkiye
| | - Sami Ullah Jan
- Department of Bioinformatics and Biosciences, Capital University of Science and Technology, Islamabad, 44000, Pakistan
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4
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Hakimabadi SG, Taylor A, Pham ALT. Factors Affecting the Adsorption of Per- and Polyfluoroalkyl Substances (PFAS) by Colloidal Activated Carbon. WATER RESEARCH 2023; 242:120212. [PMID: 37336180 DOI: 10.1016/j.watres.2023.120212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/27/2023] [Accepted: 06/09/2023] [Indexed: 06/21/2023]
Abstract
The immobilization of per- and polyfluoroalkyl substances (PFAS) by colloidal activated carbon (CAC) barriers has been proposed as a potential in-situ method to mitigate the transport of plumes of PFAS in the subsurface. However, if PFAS are continuously released from a source zone, the adsorptive sites on CAC will eventually become saturated, upon which point the breakthrough of PFAS in the barrier will occur. To predict the long-term effectiveness of CAC barriers, it is important to evaluate the factors that may affect the adsorption of PFAS on CAC. In this study, the adsorption of 7 PFAS on a polymer-stabilized CAC (i.e., PlumeStop®) and on a polymer-free CAC was investigated using batch experiments. The adsorption affinity of PFAS to CAC was in the following order: PFOS > 6:2 FTS > PFHxS > PFOA > PFBS > PFPeA > PFBA. This result indicates that hydrophobic interaction was the predominant adsorption mechanism, and that hydrophilic compounds such as PFBA and PFPeA will break through CAC barriers first. The partition coefficient Kd for the adsorption of PFAS on the polymer-stabilized CAC was 1.3 - 3.5 times smaller than the Kd for the adsorption of PFAS on the polymer-free CAC, suggesting that the polymers decreased the adsorption, presumably due to competitive sorption. Thus, the PFAS adsorption capacity of PlumeStop CAC barriers is expected to increase once the polymers are biodegraded and/or washed away. The affinity of PFOS and PFOA to CAC increased when the ionic strength of the solution increased from 1 to 100 mM, or when the concentration of Ca2+ increased from 0 to 2 mM. In contrast, less PFOS and PFOA were adsorbed in the presence of 1 - 20 mgC/L Suwannee River Fulvic Acid, which represented dissolved organic carbon, or in the presence of 10 - 100 mg/L diethylene glycol butyl ether (DGBE), which is an important component in some aqueous film-forming foam (AFFF) formulations. The presence of 0.5 - 4.8 mg/L benzene or 0.5 - 8 mg/L trichloroethylene, the co-contaminants that may comingle with PFAS at AFFF-impacted sites, diminished PFOS adsorption but had no effect or even slightly enhanced PFOA adsorption. When the initial concentration of TCE was 8 mg/L, the Kd (514 ± 240 L/g) for the adsorption of PFOS was approximately 20 times lower than that in the TCE-free system (Kd = 9,579 ± 829 L/g). The results of this study provided insights into some key factors that may affect the adsorption of PFAS in in-situ CAC barriers.
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Affiliation(s)
| | - Alannah Taylor
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Anh Le-Tuan Pham
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
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Balda M, Mackenzie K, Woszidlo S, Uhlig H, Möllmer J, Kopinke FD, Schüürmann G, Georgi A. Bottom-Up Synthesis of De-Functionalized and Dispersible Carbon Spheres as Colloidal Adsorbent. Int J Mol Sci 2023; 24:ijms24043831. [PMID: 36835241 PMCID: PMC9964220 DOI: 10.3390/ijms24043831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Recent innovative adsorption technologies for water purification rely on micrometer-sized activated carbon (AC) for ultrafast adsorption or in situ remediation. In this study, the bottom-up synthesis of tailored activated carbon spheres (aCS) from sucrose as renewable feedstock is demonstrated. The synthesis is based on a hydrothermal carbonization step followed by a targeted thermal activation of the raw material. This preserves its excellent colloid properties, i.e., narrow particle size distribution around 1 µm, ideal spherical shape and excellent aqueous dispersibility. We investigated the ageing of the freshly synthesized, highly de-functionalized AC surface in air and aqueous media under conditions relevant to the practice. A slow but significant ageing due to hydrolysis and oxidation reactions was observed for all carbon samples, leading to an increase of the oxygen contents with storage time. In this study, a tailored aCS product was generated within a single pyrolysis step with 3 vol.-% H2O in N2 in order to obtain the desired pore diameters and surface properties. Adsorption characteristics, including sorption isotherms and kinetics, were investigated with monochlorobenzene (MCB) and perfluorooctanoic acid (PFOA) as adsorbates. The product showed high sorption affinities up to log (KD/[L/kg]) of 7.3 ± 0.1 for MCB and 6.2 ± 0.1 for PFOA, respectively.
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Affiliation(s)
- Maria Balda
- Department of Environmental Engineering, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Katrin Mackenzie
- Department of Environmental Engineering, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Silke Woszidlo
- Department of Environmental Engineering, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Hans Uhlig
- Institut für Nichtklassische Chemie e.V.—INC, 04318 Leipzig, Germany
| | - Jens Möllmer
- Institut für Nichtklassische Chemie e.V.—INC, 04318 Leipzig, Germany
| | - Frank-Dieter Kopinke
- Department of Environmental Engineering, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Gerrit Schüürmann
- Institute of Organic Chemistry, Technical University Bergakademie Freiberg, 09599 Freiberg, Germany
- Department of Ecological Chemistry, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Anett Georgi
- Department of Environmental Engineering, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
- Correspondence:
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6
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Removal of benzene, MTBE and toluene from contaminated waters using biochar-based liquid activated carbon. Sci Rep 2022; 12:19651. [PMID: 36385330 PMCID: PMC9669010 DOI: 10.1038/s41598-022-24283-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 11/14/2022] [Indexed: 11/17/2022] Open
Abstract
Fuel components such as benzene, toluene, and methyl tertiary-butyl ether (MTBE) are frequently detected pollutants in groundwater resources. Ex-situ remediation technologies by activated carbon have been used for treatment for many years. However, due to high cost of these technology, more attention has been given to the in-situ remediation methods of contaminated groundwaters using liquid carbon adsorbents. Literature search showed limited studies on using adsorbents in liquid form for the removal of such contaminants. Therefore, this lab-scale study investigates the capacity of using raw biochar-based liquid activated carbon and iron-modified biochar-based liquid activated carbon to remove these pollutants. The adsorption efficiency of the synthesized liquid activated carbon and iron-modified liquid activated carbon mixed with sand, limestone, and 1:1 mixture of sand/limestone, was tested using batch suspension experiments. Adsorption by granular activated carbon was also investigated for comparison with liquid activated carbon. Results of the study revealed that mixing of liquid activated carbon or LAC-Fe on subsurface materials had not improved the removal efficiency of MTBE. At the same time, it showed a slight improvement in the adsorption efficiency of benzene and toluene. In all cases, the removal by GAC was higher with around 80% and 90% for MTBE and BT, respectively. Results also showed that benzene and toluene were better removed by liquid activated carbon and iron-modified liquid activated carbon (∼ 40%) than MTBE (∼ 20%). It is also found that water chemistry (i.e., salinity and pH) had insignificant effects on the removal efficiency of pollutants under the study conditions. It can be concluded that more research is needed to improve the capacity of biochar-based liquid-activated carbon in removing MTBE, benzene and toluene compounds that will lead to improve the utilization of liquid activated carbon for the in-situ remediation of contaminated groundwaters.
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7
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Balda M, Mackenzie K, Kopinke FD, Georgi A. Uniform and dispersible carbonaceous microspheres as quasi-liquid sorbent. CHEMOSPHERE 2022; 307:136079. [PMID: 35995183 DOI: 10.1016/j.chemosphere.2022.136079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 08/12/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
Functional colloidal carbon materials find various applications, including the remediation of contaminated water and soil in so-called particle-based in-situ remediation processes. In this study, uniform and highly dispersible micro-sized carbonaceous spheres (CS) were generated by hydrothermal carbonization (HTC) of sucrose in the presence of carboxymethyl cellulose (CMC) as environmentally friendly polyelectrolyte stabilizer. In order to ensure their optimal subsurface delivery and formation of a self-contained treatment zone, a narrow size distribution and low agglomeration tendency of the particles is desired. Therefore, the obtained CS were thoroughly characterized and optimized with respect to their colloidal properties which are a crucial factor for their application as quasi-liquid sorbent. The as-prepared uniform CS are readily dispersible into single particles in water as confirmed by digital microscopy and form stable suspensions. Due to their perfectly spherical shape, particle sedimentation in aqueous suspensions is well predicted by Stokes' law. High sorption coefficients on the synthesized CS KD,CS were determined for phenanthrene (up to log (KD,CS/[L kg-1]) = 5) and other hydrophobic groundwater contaminants. This confirms the application potential of the CS, which were prepared by an economic low-temperature process using sucrose as bio-based precursor, for generating in-situ sorption barriers for groundwater and soil remediation.
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Affiliation(s)
- Maria Balda
- Department of Environmental Engineering, Helmholtz Centre for Environmental Research - UFZ, D-04318 Leipzig, Germany.
| | - Katrin Mackenzie
- Department of Environmental Engineering, Helmholtz Centre for Environmental Research - UFZ, D-04318 Leipzig, Germany
| | - Frank-Dieter Kopinke
- Department of Environmental Engineering, Helmholtz Centre for Environmental Research - UFZ, D-04318 Leipzig, Germany
| | - Anett Georgi
- Department of Environmental Engineering, Helmholtz Centre for Environmental Research - UFZ, D-04318 Leipzig, Germany
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8
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McDonough JT, Anderson RH, Lang JR, Liles D, Matteson K, Olechiw T. Field-Scale Demonstration of PFAS Leachability Following In Situ Soil Stabilization. ACS OMEGA 2022; 7:419-429. [PMID: 35036711 PMCID: PMC8756798 DOI: 10.1021/acsomega.1c04789] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 12/09/2021] [Indexed: 05/06/2023]
Abstract
A field-scale validation is summarized comparing the efficacy of commercially available stabilization amendments with the objective of mitigating per- and polyfluoroalkyl substance (PFAS) leaching from aqueous film-forming foam (AFFF)-impacted source zones. The scope of this work included bench-scale testing to evaluate multiple amendments and application concentrations to mitigate PFAS leachability and the execution of field-scale soil mixing in an AFFF-impacted fire-training area with nearly 2.5 years of post-soil mixing monitoring to validate reductions in PFAS leachability. At the bench scale, several amendments were evaluated and the selection of two amendments for field-scale evaluation was informed: FLUORO-SORB Adsorbent (FS) and RemBind (RB). Five ∼28 m3 test pits (approximately 3 m wide by 3 m long by 3 m deep) were mixed at a site using conventional construction equipment. One control test pit (Test Pit 1) included Portland cement (PC) only (5% dry weight basis). The other four test pits (Test Pits 2 through 5) compared 5 and 10% ratios (dry weight basis) of FS and RB (also with PC). Five separate monitoring events included two to three sample cores collected from each test pit for United States Environmental Protection Agency (USEPA) Method 1315 leaching assessment. After 1 year, a mass balance for each test pit was attempted comparing the total PFAS soil mass before, during, and after leach testing. Bench-scale and field-scale data were in good agreement and demonstrated >99% decrease in total PFAS leachability (mass basis; >98% mole basis) as confirmed by the total oxidizable precursor assay, strongly supporting the chemical stabilization of PFAS.
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Affiliation(s)
- Jeffrey T. McDonough
- Arcadis, 630 Plaza Drive
Suite 200, Highlands Ranch, Colorado 80129, United
States
- . Phone: 267-615-1863
| | - Richard H. Anderson
- Air
Force Civil Engineer Center (AFCEC), San Antonio, Texas 78056, United States
| | - Johnsie R. Lang
- Arcadis, 630 Plaza Drive
Suite 200, Highlands Ranch, Colorado 80129, United
States
| | - David Liles
- Arcadis, 630 Plaza Drive
Suite 200, Highlands Ranch, Colorado 80129, United
States
| | - Kasey Matteson
- Arcadis, 630 Plaza Drive
Suite 200, Highlands Ranch, Colorado 80129, United
States
| | - Theresa Olechiw
- Arcadis, 630 Plaza Drive
Suite 200, Highlands Ranch, Colorado 80129, United
States
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9
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McGregor R, Zhao Y. The in situ treatment of TCE and PFAS in groundwater within a silty sand aquifer. ACTA ACUST UNITED AC 2021. [DOI: 10.1002/rem.21675] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Rick McGregor
- InSitu Remediation Services Ltd St George Ontario Canada
| | - Ye Zhao
- InSitu Remediation Services Ltd St George Ontario Canada
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10
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McGregor R. Six pilot‐scale studies evaluating the in situ treatment of PFAS in groundwater. ACTA ACUST UNITED AC 2020. [DOI: 10.1002/rem.21653] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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11
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Liu C, Hatton J, Arnold WA, Simcik MF, Pennell KD. In Situ Sequestration of Perfluoroalkyl Substances Using Polymer-Stabilized Powdered Activated Carbon. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:6929-6936. [PMID: 32379438 DOI: 10.1021/acs.est.0c00155] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Remediation of groundwater impacted by per- and polyfluoroalkyl substances (PFAS) is particularly challenging due to the resistance of the molecule to oxidation because of the strength of the carbon-fluorine bond and the need to achieve low nanogram per liter drinking water targets. Previous studies have shown that activated carbon is an effective sorbent for removal of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in conventional water treatment systems. The objective of this study was to evaluate the in situ delivery and sorptive capacity of an aqueous suspension containing powdered activated carbon (PAC) stabilized with polydiallyldimethylammonium chloride (polyDADMAC). Batch reactor studies demonstrated substantial adsorption of PFOA and PFOS by polyDADMAC-stabilized PAC, which yielded Freundlich adsorption coefficients of 156 and 629 L/g-n, respectively. In columns packed with 40-50 mesh Ottawa sand, injection of a PAC (1000 mg/L) + polyDADMAC (5000 mg/L) suspension created a sorptive region that increased subsequent PFOA and PFOS retention by 3 orders of magnitude relative to untreated control columns, consistent with the mass of retained PAC. Experiments conducted in a heterogeneous aquifer cell further demonstrated the potential for stabilized-PAC to be an effective in situ treatment option for PFAS-impacted groundwater.
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Affiliation(s)
- Chen Liu
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - James Hatton
- Jacobs Engineering Group, Incorporated, Englewood, Colorado 80112, United States
| | - William A Arnold
- Department of Civil, Environmental and Geo-Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455, United States
| | - Matt F Simcik
- School of Public Health, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Kurt D Pennell
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
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12
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McGregor R. Distribution of Colloidal and Powdered Activated Carbon for the <i>in Situ</i> Treatment of Groundwater. ACTA ACUST UNITED AC 2020. [DOI: 10.4236/jwarp.2020.1212060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Sorengard M, Kleja DB, Ahrens L. Stabilization of per- and polyfluoroalkyl substances (PFASs) with colloidal activated carbon (PlumeStop®) as a function of soil clay and organic matter content. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 249:109345. [PMID: 31487666 DOI: 10.1016/j.jenvman.2019.109345] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 06/10/2023]
Abstract
The global problem of contamination of drinking water sources and the aquatic environment with per- and polyfluoroalkyl substances (PFASs) originating from highly contaminated soils is addressed in this study. For the first time, a colloidal activated carbon (AC) product (PlumeStop®) was systematically assessed for PFASs stabilization in soil. Colloidal (particle size 0.1-1.1 μm) AC has the advantage that field application is non-intrusive, comprising injection under high pressure in situ at PFAS-contaminated soil hotspots. In the assessment, 10 different soil mixtures with gradually increasing organic carbon and clay fractions were spiked with 18 different PFASs of varying perfluorocarbon chain length and four different functional groups and aged for one year. Equilibrium leaching tests showed that the ability of colloidal AC to increase sorption of PFASs to soil was highly dependent on PFAS perfluorocarbon chain length. The best treatment efficiency was observed for perfluorocarbon chain lengths 6-7 at which colloidal AC resulted in sorption of 81%, 85%, and 86% for perfluorooctanoate (PFOA), 6:2 fluorotelomer sulfonate (6:2 FTSA) and perfluorohexane sulfonate, (PFHxS), respectively. Sorption of individual PFASs decreased significantly (p < 0.05) with increasing organic carbon content in soil treated with colloidal AC indicating stearic hindrance of the ACs pore structure. On the other hand, the sorption of the majority of PFASs increased significantly (p < 0.05) with increasing clay content in colloidal AC-treated soil, which can be explained by increase in surface area that colloidal AC can sorb to. Overall, the results indicate that the colloidal AC product tested can be useful in remediation approaches for certain PFASs under specific field conditions and PFAS contamination.
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Affiliation(s)
- M Sorengard
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), Box 7050, SE-750 07, Uppsala, Sweden.
| | - Dan Berggren Kleja
- Swedish Geotechnical Institute, Kornhamnstorg 61, Stockholm, 111 27 , Sweden
| | - Lutz Ahrens
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), Box 7050, SE-750 07, Uppsala, Sweden
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