Comparative removal of Suwannee River natural organic matter and perfluoroalkyl acids by anion exchange: Impact of polymer composition and mobile counterion

Lerys Laura del Moral; Youn Jeong Choi; Treavor H. Boyer

doi:10.1016/j.watres.2020.115846

Comparative removal of Suwannee River natural organic matter and perfluoroalkyl acids by anion exchange: Impact of polymer composition and mobile counterion

Lerys Laura del Moral, Youn Jeong Choi, Treavor H. Boyer

Engineering, Ira A. Fulton Schools of (IAFSE)

Research output: Contribution to journal › Article › peer-review

36 Scopus citations

Abstract

Anion exchange resin (AER) adsorption is an established technology for water treatment and groundwater remediation. Two contaminants amenable to AER treatment are natural organic matter (NOM) and per- and polyfluoroalkyl substances (PFAS), specifically anionic perfluoroalkyl acids (PFAAs) such as perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). NOM is ubiquitous in natural waters and is often targeted for removal. PFAS occurrence in water resources is a human health concern. Accordingly, the goal of this research was to provide new insights on the use of AER for water treatment considering separate and combined removal of NOM and PFAAs. Batch experiments were conducted comparing polystyrene and polyacrylic AER in both chloride- and sulfate-forms using natural groundwater spiked with Suwannee River natural organic matter (SRNOM) and/or six PFAAs. The polymer composition of the AER had a significant impact on contaminant removal with polystyrene resin more effective for PFAA removal and polyacrylic resin more effective for SRNOM removal. Both resins had type I quaternary ammonium functional groups; however, the polyacrylic resin had trimethyl ammonium whereas the polystyrene resin had triethyl ammonium. Therefore, the influence of polymer composition could not be isolated conclusively from functional group chemistry. Polystyrene AER showed greater removal of PFAAs with sulfonate than carboxylate head group and 8-carbon than 4-carbon chain length. Removal of SRNOM and PFAAs by both resin polymer compositions were greater when sulfate was the mobile counterion ion than chloride. The results of this research have important implications for using AER for water treatment and remediation. Foremost, polymer composition and mobile counterion form of the resin can be selected to target specific contaminants and maximize contaminant removal. When contaminants have unique interactions with AER such as SRNOM and polyacrylic resin and PFAAs and polystyrene resin, the presence of one contaminant does not impact removal of the other contaminant.

Original language	English (US)
Article number	115846
Journal	Water Research
Volume	178
DOIs	https://doi.org/10.1016/j.watres.2020.115846
State	Published - Jul 1 2020

Keywords

Ion exchange
Per- and polyfluoroalkyl substances (PFAS)
Perfluorooctane sulfonate (PFOS)
Perfluorooctanoate (PFOA)
Polyacrylic
Polystyrene

ASJC Scopus subject areas

Water Science and Technology
Ecological Modeling
Pollution
Waste Management and Disposal
Environmental Engineering
Civil and Structural Engineering

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10.1016/j.watres.2020.115846

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@article{7ed7c926bff3478eb0d2347927aac4d3,

title = "Comparative removal of Suwannee River natural organic matter and perfluoroalkyl acids by anion exchange: Impact of polymer composition and mobile counterion",

abstract = "Anion exchange resin (AER) adsorption is an established technology for water treatment and groundwater remediation. Two contaminants amenable to AER treatment are natural organic matter (NOM) and per- and polyfluoroalkyl substances (PFAS), specifically anionic perfluoroalkyl acids (PFAAs) such as perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). NOM is ubiquitous in natural waters and is often targeted for removal. PFAS occurrence in water resources is a human health concern. Accordingly, the goal of this research was to provide new insights on the use of AER for water treatment considering separate and combined removal of NOM and PFAAs. Batch experiments were conducted comparing polystyrene and polyacrylic AER in both chloride- and sulfate-forms using natural groundwater spiked with Suwannee River natural organic matter (SRNOM) and/or six PFAAs. The polymer composition of the AER had a significant impact on contaminant removal with polystyrene resin more effective for PFAA removal and polyacrylic resin more effective for SRNOM removal. Both resins had type I quaternary ammonium functional groups; however, the polyacrylic resin had trimethyl ammonium whereas the polystyrene resin had triethyl ammonium. Therefore, the influence of polymer composition could not be isolated conclusively from functional group chemistry. Polystyrene AER showed greater removal of PFAAs with sulfonate than carboxylate head group and 8-carbon than 4-carbon chain length. Removal of SRNOM and PFAAs by both resin polymer compositions were greater when sulfate was the mobile counterion ion than chloride. The results of this research have important implications for using AER for water treatment and remediation. Foremost, polymer composition and mobile counterion form of the resin can be selected to target specific contaminants and maximize contaminant removal. When contaminants have unique interactions with AER such as SRNOM and polyacrylic resin and PFAAs and polystyrene resin, the presence of one contaminant does not impact removal of the other contaminant.",

keywords = "Ion exchange, Per- and polyfluoroalkyl substances (PFAS), Perfluorooctane sulfonate (PFOS), Perfluorooctanoate (PFOA), Polyacrylic, Polystyrene",

author = "{Laura del Moral}, Lerys and Choi, {Youn Jeong} and Boyer, {Treavor H.}",

note = "Funding Information: This research was supported by SERDP grant ER18-1063 Regenerable Resin Sorbent Technologies with Regenerant Solution Recycling for Sustainable Treatment of Per- and Polyfluoroalkyl Substances (PFASs) . The authors thank Christopher Higgins at Colorado School of Mines for supporting PFAS analysis. This paper was improved by the thorough comments of two anonymous reviewers. Funding Information: A statistical analysis was not conducted on the results in Fig. 3 because only one sample out of the triplicate samples for each resin dose was analyzed for PFAAs. Comparing the results in Fig. 3, on average subplot b shows lower C/C0 bars than subplot a, and subplot d shows lower C/C0 bars than subplot c. This trend is most noticeable at AER doses on 0.25 and 0.5 mL/L and for PFBA at all resin doses. This was a similar result as DOC removal, which supports the conjecture of enhanced contaminant removal using a divalent counterion with a monovalent-ion-selective resin (e.g., A520E). To confirm this conjecture, additional comparisons of divalent vs. monovalent counterions would be needed. The results in Fig. 3 did not show an obvious impact of the presence of SRNOM on PFAA removal by AER, meaning that the presence of SRNOM did not interfere with PFAA removal. Although limited data are available, previous studies also show minimal impact of NOM on PFAA removal by AER (Dixit et al., 2019; Kothawala et al., 2017). This indicates that AER (A520E in this case) is highly selective for PFAAs because the average DOC-to-PFAA equivalent ratio was 11.6 meaning there was >10 ? more NOM than PFAAs competing for ion-exchange sites.This research was supported by SERDP grant ER18-1063 Regenerable Resin Sorbent Technologies with Regenerant Solution Recycling for Sustainable Treatment of Per- and Polyfluoroalkyl Substances (PFASs). The authors thank Christopher Higgins at Colorado School of Mines for supporting PFAS analysis. This paper was improved by the thorough comments of two anonymous reviewers. Publisher Copyright: {\textcopyright} 2020 Elsevier Ltd",

year = "2020",

month = jul,

day = "1",

doi = "10.1016/j.watres.2020.115846",

language = "English (US)",

volume = "178",

journal = "Water Research",

issn = "0043-1354",

publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Comparative removal of Suwannee River natural organic matter and perfluoroalkyl acids by anion exchange

T2 - Impact of polymer composition and mobile counterion

AU - Laura del Moral, Lerys

AU - Choi, Youn Jeong

AU - Boyer, Treavor H.

N1 - Funding Information: This research was supported by SERDP grant ER18-1063 Regenerable Resin Sorbent Technologies with Regenerant Solution Recycling for Sustainable Treatment of Per- and Polyfluoroalkyl Substances (PFASs) . The authors thank Christopher Higgins at Colorado School of Mines for supporting PFAS analysis. This paper was improved by the thorough comments of two anonymous reviewers. Funding Information: A statistical analysis was not conducted on the results in Fig. 3 because only one sample out of the triplicate samples for each resin dose was analyzed for PFAAs. Comparing the results in Fig. 3, on average subplot b shows lower C/C0 bars than subplot a, and subplot d shows lower C/C0 bars than subplot c. This trend is most noticeable at AER doses on 0.25 and 0.5 mL/L and for PFBA at all resin doses. This was a similar result as DOC removal, which supports the conjecture of enhanced contaminant removal using a divalent counterion with a monovalent-ion-selective resin (e.g., A520E). To confirm this conjecture, additional comparisons of divalent vs. monovalent counterions would be needed. The results in Fig. 3 did not show an obvious impact of the presence of SRNOM on PFAA removal by AER, meaning that the presence of SRNOM did not interfere with PFAA removal. Although limited data are available, previous studies also show minimal impact of NOM on PFAA removal by AER (Dixit et al., 2019; Kothawala et al., 2017). This indicates that AER (A520E in this case) is highly selective for PFAAs because the average DOC-to-PFAA equivalent ratio was 11.6 meaning there was >10 ? more NOM than PFAAs competing for ion-exchange sites.This research was supported by SERDP grant ER18-1063 Regenerable Resin Sorbent Technologies with Regenerant Solution Recycling for Sustainable Treatment of Per- and Polyfluoroalkyl Substances (PFASs). The authors thank Christopher Higgins at Colorado School of Mines for supporting PFAS analysis. This paper was improved by the thorough comments of two anonymous reviewers. Publisher Copyright: © 2020 Elsevier Ltd

PY - 2020/7/1

Y1 - 2020/7/1

N2 - Anion exchange resin (AER) adsorption is an established technology for water treatment and groundwater remediation. Two contaminants amenable to AER treatment are natural organic matter (NOM) and per- and polyfluoroalkyl substances (PFAS), specifically anionic perfluoroalkyl acids (PFAAs) such as perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). NOM is ubiquitous in natural waters and is often targeted for removal. PFAS occurrence in water resources is a human health concern. Accordingly, the goal of this research was to provide new insights on the use of AER for water treatment considering separate and combined removal of NOM and PFAAs. Batch experiments were conducted comparing polystyrene and polyacrylic AER in both chloride- and sulfate-forms using natural groundwater spiked with Suwannee River natural organic matter (SRNOM) and/or six PFAAs. The polymer composition of the AER had a significant impact on contaminant removal with polystyrene resin more effective for PFAA removal and polyacrylic resin more effective for SRNOM removal. Both resins had type I quaternary ammonium functional groups; however, the polyacrylic resin had trimethyl ammonium whereas the polystyrene resin had triethyl ammonium. Therefore, the influence of polymer composition could not be isolated conclusively from functional group chemistry. Polystyrene AER showed greater removal of PFAAs with sulfonate than carboxylate head group and 8-carbon than 4-carbon chain length. Removal of SRNOM and PFAAs by both resin polymer compositions were greater when sulfate was the mobile counterion ion than chloride. The results of this research have important implications for using AER for water treatment and remediation. Foremost, polymer composition and mobile counterion form of the resin can be selected to target specific contaminants and maximize contaminant removal. When contaminants have unique interactions with AER such as SRNOM and polyacrylic resin and PFAAs and polystyrene resin, the presence of one contaminant does not impact removal of the other contaminant.

AB - Anion exchange resin (AER) adsorption is an established technology for water treatment and groundwater remediation. Two contaminants amenable to AER treatment are natural organic matter (NOM) and per- and polyfluoroalkyl substances (PFAS), specifically anionic perfluoroalkyl acids (PFAAs) such as perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). NOM is ubiquitous in natural waters and is often targeted for removal. PFAS occurrence in water resources is a human health concern. Accordingly, the goal of this research was to provide new insights on the use of AER for water treatment considering separate and combined removal of NOM and PFAAs. Batch experiments were conducted comparing polystyrene and polyacrylic AER in both chloride- and sulfate-forms using natural groundwater spiked with Suwannee River natural organic matter (SRNOM) and/or six PFAAs. The polymer composition of the AER had a significant impact on contaminant removal with polystyrene resin more effective for PFAA removal and polyacrylic resin more effective for SRNOM removal. Both resins had type I quaternary ammonium functional groups; however, the polyacrylic resin had trimethyl ammonium whereas the polystyrene resin had triethyl ammonium. Therefore, the influence of polymer composition could not be isolated conclusively from functional group chemistry. Polystyrene AER showed greater removal of PFAAs with sulfonate than carboxylate head group and 8-carbon than 4-carbon chain length. Removal of SRNOM and PFAAs by both resin polymer compositions were greater when sulfate was the mobile counterion ion than chloride. The results of this research have important implications for using AER for water treatment and remediation. Foremost, polymer composition and mobile counterion form of the resin can be selected to target specific contaminants and maximize contaminant removal. When contaminants have unique interactions with AER such as SRNOM and polyacrylic resin and PFAAs and polystyrene resin, the presence of one contaminant does not impact removal of the other contaminant.

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KW - Per- and polyfluoroalkyl substances (PFAS)

KW - Perfluorooctane sulfonate (PFOS)

KW - Perfluorooctanoate (PFOA)

KW - Polyacrylic

KW - Polystyrene

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Comparative removal of Suwannee River natural organic matter and perfluoroalkyl acids by anion exchange: Impact of polymer composition and mobile counterion

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Keywords

ASJC Scopus subject areas

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