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.

中文翻译：

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通过一次性和可再生阴离子交换树脂去除旧的全氟烷基酸和新兴的全氟烷基醚酸和多氟烷基醚酸：快速小规模色谱柱测试和模型拟合

快速小规模柱测试 (RSSCT) 用于研究通过离子交换去除饮用水处理中的全氟烷基物质和多氟烷基物质 (PFAS)。使用一次性 PFAS 选择性阴离子交换树脂 (AER1) 和可再生通用阴离子交换树脂 (AER2) 对 15 种新兴全氟烷基醚酸和全氟烷基醚酸以及 6 种传统全氟烷基酸类似物进行了突破性研究。 Bohart-Adams模型用于描述和预测突破，在大多数情况下，建模结果与RSSCT结果合理一致，从而为未来的应用提供更短的RSSCT持续时间。 AER1 表现出高吸收能力，在 144,175 BV 连续运行期间，21 种测试的 PFAS 中有 11 种没有突破，从而在许多应用场景中符合新的国家初级饮用水法规。 AER2 对大多数 PFAS 表现出更快的突破，但对于饮用水处理来说并不是一个有前途的选择。然而，通过模型拟合得出的总 PFAS 容量和通过测量吸附的总 PFAS 仅为完全突破时两种树脂容量的 0.01%，这表明即使对于 PFAS 选择性 AER1，PFAS 也只能占据离子交换位点的一小部分。 PFAS基团中醚基的插入导致了后来的突破，并且直链异构体比支链异构体更容易被树脂捕获。总体而言，当 PFAS 分子体积增加时，PFAS 吸收能力增加，动力学降低。使用 10% NaCl 溶液进行再生时，AER2 中部分释放了 PFAS，但 AER1 中未释放 PFAS，且释放的短链 PFAS 多于长链 PFAS。醚基团插入降低了 AER2 再生过程中 PFAS 的回收率。再生树脂比原始树脂表现出更快的突破，这使得它们不利于饮用水处理应用。在原始 AER1 中观察到短链 PFAS 被长链 PFAS 吸附置换，并且两种树脂都发生再生后浸出，这两种现象使树脂成为长期使用的可能 PFAS 来源。