Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA.
Department of Chemical Engineering, Miami University, Oxford, OH 45056, USA.
J Hazard Mater. 2022 Jun 5;431:128521. doi: 10.1016/j.jhazmat.2022.128521. Epub 2022 Feb 22.
Perfluorooctanoic acid (PFOA) is a persistent and recalcitrant organic contaminant of exceptional environmental concern, and its removal from water has increasingly attracted global attention due to its wide distribution and strong bioaccumulation. Adsorption is considered an effective technique for PFOA removal and more efficient PFOA sorbents are still of interest. This study developed a dual grafted fluorinated hydrocarbon amine weak anion exchange (WAX) polymeric resin (Sepra-WAX-KelF-PEI) for PFOA removal from water. This polymer was synthesized by a two-step amine grafting reaction procedure involving first the reaction of the Sepra-WAX hydrocarbon polymer with poly(vinylidinefluoride-chlorotrifluoroethylene) (Kel-F 800) and then a second reaction with polyethyleneimine (PEI). Characterization of the synthesized polymers was performed using scanning electron microscopy and elemental analysis (F and Cl) by energy dispersive X-ray spectroscopy. The PFOA adsorption performance evaluations were conducted by packed column flow analyses with on-line detection. The results show the breakthrough of the Sepra-WAX-KelF-PEI synthesized with optimum stoichiometry was two times better than the starting anion exchange polymer Sepra-WAX, and six times better than powdered activated carbon, when using the same column size. The adsorption mechanisms of this novel adsorbent including hydrophobic interaction and electrostatic interaction were also clarified in this study. The adsorption kinetic parameters of the two optimum synthesized sorbents were determined using the Thomas model, the Yoon-Nelson model, and batch isotherm studies, and compared with those found with activated carbon and the starting WAX resin. Good agreement of the batch isotherm and column studies with respect to adsorption capacities trends between all three polymers (Sepra-WAX, Sepra-WAX-KelF, and Sepra-WAX-KelF-PEI) were noted.
全氟辛酸（PFOA）是一种持久性和顽固性的有机污染物，对环境具有特殊的关注，由于其广泛的分布和强烈的生物累积性，从水中去除 PFOA 日益受到全球关注。吸附被认为是去除 PFOA 的有效技术，因此更高效的 PFOA 吸附剂仍然是人们关注的焦点。本研究开发了一种双接枝氟烃胺弱阴离子交换（WAX）聚合物树脂（Sepra-WAX-KelF-PEI），用于从水中去除 PFOA。该聚合物是通过两步胺接枝反应程序合成的，首先是 Sepra-WAX 烃聚合物与聚（偏二氟乙烯-氯三氟乙烯）（Kel-F 800）反应，然后与聚乙烯亚胺（PEI）反应。通过扫描电子显微镜和能量色散 X 射线光谱的元素分析（F 和 Cl）对合成聚合物进行了表征。通过在线检测的填充柱流动分析评估了 PFOA 的吸附性能。结果表明，在使用相同的柱尺寸时，最佳化学计量比合成的 Sepra-WAX-KelF-PEI 的穿透时间是起始阴离子交换聚合物 Sepra-WAX 的两倍，是粉末状活性炭的六倍。本研究还阐明了这种新型吸附剂的吸附机制，包括疏水相互作用和静电相互作用。通过 Thomas 模型、Yoon-Nelson 模型和批量等温线研究确定了两种最佳合成吸附剂的吸附动力学参数，并与活性炭和起始 WAX 树脂的吸附动力学参数进行了比较。所有三种聚合物（Sepra-WAX、Sepra-WAX-KelF 和 Sepra-WAX-KelF-PEI）的批量等温线和柱研究的吸附容量趋势都很好地一致。
