Remove legacy perfluoroalkyl acids and emerging per- and polyfluoroalkyl ether acids by single-use and regenerable anion exchange resins: Rapid small-scale column tests and model fits.

Autor: Liu B; Department of Civil and Environmental Engineering, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA. Electronic address: Bingchuan.Liu@charlotte.edu., Liu YL; Department of Civil and Environmental Engineering, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA., Sun M; Department of Civil and Environmental Engineering, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA.
Jazyk: angličtina
Zdroj: Water research [Water Res] 2024 Jun 15; Vol. 257, pp. 121661. Date of Electronic Publication: 2024 Apr 22.
DOI: 10.1016/j.watres.2024.121661
Abstrakt: Rapid small-scale column tests (RSSCT) are used to study the removal of per- and polyfluoroalkyl substances (PFAS) for drinking water treatment by ion exchange. Breakthroughs of 15 emerging per- and perfluoroalkyl ether acids and six legacy perfluoroalkyl acid analogs are studied using a single-use PFAS-selective anion exchange resin (AER1) and a regenerable, generic anion exchange resin (AER2). The Bohart-Adams model was used to describe and predict breakthrough, with the modeled results reasonably aligned with RSSCT results in most cases, enabling shorter RSSCT duration for future applications. AER1 exhibited high uptake capacity with no breakthrough for 11 of the 21 tested PFAS during the 144,175 BV continuous operation, allowing compliance with the new National Primary Drinking Water Regulation in many application scenarios. AER2 exhibited much faster breakthroughs for most PFAS and is not a promising option for drinking water treatment. However, the summed PFAS capacity via model fit and total PFAS adsorbed via measurement were only <0.01 % of both resin capacities at full breakthrough, suggesting PFAS could only occupy a tiny portion of the ion exchange sites even for the PFAS-selective AER1. Ether group insertion in the PFAS group leads to later breakthrough, and linear isomers were better captured by the resins than the branched isomers. Overall, PFAS uptake capacity increases and kinetics decrease when the PFAS molecular volume increases. Regeneration using 10 % NaCl solutions partially released PFAS from AER2 but not from AER1, with more short-chain PFAS released than long-chain ones. Ether group insertion decreased the PFAS recoveries during the regeneration of AER2. The regenerated resins showed much faster breakthroughs than the pristine resins, making them unfavorable for drinking water treatment applications. Adsorption displacement of short-chain PFAS by long-chain PFAS was observed in pristine AER1, and post-regeneration leaching occurred for both resins, both phenomena making the resins a possible PFAS source in long-term use.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Bingchuan Liu reports financial support was provided by North Carolina Policy Collaborative. Yen-Ling Liu reports financial support was provided by North Carolina Policy Collaborative. Mei Sun reports financial support was provided by North Carolina Policy Collaborative. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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