Novel insights into the competitive adsorption behavior and mechanism of per- and polyfluoroalkyl substances on the anion-exchange resin

Wei Wang; Xin Mi; Ziming Zhou; Shuangxi Zhou; Chunli Li; Xue Hu; Delin Qi; Shubo Deng

doi:10.1016/j.jcis.2019.09.066

Novel insights into the competitive adsorption behavior and mechanism of per- and polyfluoroalkyl substances on the anion-exchange resin

J Colloid Interface Sci. 2019 Dec 1:557:655-663. doi: 10.1016/j.jcis.2019.09.066. Epub 2019 Sep 19.

Authors

Wei Wang¹, Xin Mi², Ziming Zhou², Shuangxi Zhou², Chunli Li², Xue Hu², Delin Qi², Shubo Deng³

Affiliations

¹ State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xi'ning, Qinghai Province 810016, China; State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), Beijing Key Laboratory for Emerging Organic Contaminants Control, School of Environment, Tsinghua University, Beijing 100084, China.
² State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xi'ning, Qinghai Province 810016, China.
³ State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), Beijing Key Laboratory for Emerging Organic Contaminants Control, School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: dengshubo@tsinghua.edu.cn.

PMID: 31561082
DOI: 10.1016/j.jcis.2019.09.066

Abstract

Per- and polyfluoroalkyl substances (PFASs) are widely used and co-exist in various aquatic environments, but their co-removal is not clear. In this study, the competitive adsorption behavior and mechanism of six traditional and emerging PFASs on anion-exchange resin IRA67 in the bisolute and mixed systems were studied. The adsorption equilibrium of the long-chain PFASs was at least 96 h whereas 48 h was required for the short-chain PFASs. When the PFASs were co-removed in the bisolute system, their competition was not obvious at low PFAS concentration of 0.01597 mmol/L due to the relatively adequate adsorption sites. When the concentrations of PFASs were increased to 0.07666 mmol/L, the removal of perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS) decreased by 77.78% and 72.09%, respectively. The competitive experiments showed that the adsorbed short-chain PFASs could be replaced by the long-chain ones, which was closely related to their hydrophobicity, backbone and functional groups. With the increase of solution pH from 3 to 7, the polyamine groups on the resin IRA67 were transferred to the base forms and the effective adsorption sites decreased, resulting in a more obvious competitive replacement behavior. This study suggested that the PFASs with long chain could be more effectively removed from the coexisting PFASs solution by the anion-exchange resins, and the short-chain PFASs in water may be removed when high dosage of anion-exchange resins is applied or the solution pH is decreased.

Keywords: Adsorption behavior; Adsorption mechanism; Anion exchange resin; Competitive adsorption; PFASs.