School of Engineering, Brown University, Providence, RI 02912, United States.
Department of Civil and Environmental Engineering, Auburn University, Auburn, AL 36830, United States.
J Hazard Mater. 2022 Jan 15;422:126960. doi: 10.1016/j.jhazmat.2021.126960. Epub 2021 Aug 19.
Remediation of groundwater impacted by per- and polyfluoroalkyl substances (PFAS) is challenging due to the strength of the carbon-fluorine bond and the need to achieve nanogram per liter drinking water targets. Previous studies have shown that ion exchange resins can serve as effective sorbents for the removal of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in conventional water treatment systems. The objectives of this study were to evaluate the in situ delivery and PFAS sorption capacity of a polymer-stabilized ion exchange resin (S-IXR) consisting of Amberlite® IRA910 beads and Pluronic® F-127 in a quartz sand. At concentrations below 100 µg/L, individual and mixed PFAS adsorption on resin beads exhibited linear isotherms with no apparent competitive effects. However, at concentrations up to 100 mg/L, PFAS adsorption isotherms were non-linear and a mixture of six PFAS exhibited strong competitive effects. In columns packed with 40-50 mesh Ottawa sand, injection of the S-IXR suspension created a uniform sorptive zone that increased PFOA or PFOS retention by more than five orders-of-magnitude compared to untreated control columns. Multi-solute column studies revealed earlier breakthrough of shorter-chain length PFAS, which was consistent with the mixed PFAS adsorption data. These findings indicate that injectable ion exchange resins could provide an effective in situ remediation strategy for PFAS-impacted groundwater plumes.
受全氟和多氟烷基物质 (PFAS) 影响的地下水的修复具有挑战性，这是由于碳氟键的强度以及需要达到纳克/升饮用水目标所致。先前的研究表明，离子交换树脂可以作为有效吸附剂，用于去除常规水处理系统中的全氟辛酸 (PFOA) 和全氟辛烷磺酸 (PFOS)。本研究的目的是评估由 Amberlite®IRA910 珠和 Pluronic®F-127 组成的聚合物稳定离子交换树脂 (S-IXR) 在石英砂中的原位输送和 PFAS 吸附能力。在低于 100µg/L 的浓度下，单独和混合 PFAS 在树脂珠上的吸附表现出线性等温线，没有明显的竞争效应。然而，在高达 100mg/L 的浓度下，PFAS 吸附等温线是非线性的，六种 PFAS 的混合物表现出强烈的竞争效应。在填充有 40-50 目 Ottawa 砂的柱中，注入 S-IXR 悬浮液会形成一个均匀的吸附区，与未经处理的对照柱相比，PFOA 或 PFOS 的保留增加了五个数量级以上。多溶质柱研究表明，较短链长的 PFAS 较早达到穿透点，这与混合 PFAS 吸附数据一致。这些发现表明，可注入的离子交换树脂可为受 PFAS 影响的地下水羽流提供有效的原位修复策略。
