Lin Zhi-Wei, Wang Jieyuan, Dyakiv Yaryna, Helbling Damian E, Dichtel William R
Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.
School of Civil and Environmental Engineering, Cornell University, Ithaca, New York 14853, United States.
ACS Appl Mater Interfaces. 2024 Jun 5;16(22):28409-28422. doi: 10.1021/acsami.4c01969. Epub 2024 May 20.
Cross-linked β-cyclodextrin (β-CD) polymers are promising adsorbents for the removal of per- and polyfluoroalkyl substances (PFAS) from contaminated water sources, including contaminated groundwater, drinking water, and wastewater. We previously reported porous, styrene-functionalized β-cyclodextrin (StyDex) polymers derived from radical polymerization with vinyl comonomers. Because of the versatility of these polymerizations, StyDex polymer compositions are tunable, which facilitates efforts to establish structure-adsorption relationships and to discover improved materials. Here, we evaluate the material properties and PFAS adsorption of 20 StyDex derivatives with varied comonomer structure and loading, regiochemistry of styrene placement on the CD monomer, and CD size. A StyDex polymer containing ,'-dimethylbutyl ammonium ions exhibited the most effective PFAS adsorption in batch experiments. Furthermore, a StyDex polymer containing β-CD exhibited size-selective host-guest interactions with perfluoroalkyl acids (PFAAs) and neutral contaminants in aqueous electrolyte when compared to similar polymers containing either α-CD or γ-CD. Polymers based on β-CD monomers with an average of seven styrene groups randomly positioned over the 21 available hydroxyl groups performed similarly to those based on a β-CD monomer functionalized regiospecifically at each of the seven 6' positions. The former β-CD monomer is prepared in a single step from unmodified β-CD, so the ability to use it without compromising performance demonstrates promise for developing economically competitive adsorbents. These results offered important insights into structure-adsorption properties of StyDex polymers and will inform the design of improved StyDex formulations.
交联β-环糊精（β-CD）聚合物是一种很有前景的吸附剂，可用于从受污染的水源中去除全氟和多氟烷基物质（PFAS），这些水源包括受污染的地下水、饮用水和废水。我们之前报道了通过与乙烯基共聚单体进行自由基聚合得到的多孔、苯乙烯功能化β-环糊精（StyDex）聚合物。由于这些聚合反应具有多样性，StyDex聚合物的组成是可调的，这有助于建立结构-吸附关系并发现性能更优的材料。在此，我们评估了20种StyDex衍生物的材料特性和PFAS吸附性能，这些衍生物具有不同的共聚单体结构和负载量、苯乙烯在CD单体上的位置化学以及CD尺寸。在批量实验中，一种含有,'-二甲基丁基铵离子的StyDex聚合物表现出最有效的PFAS吸附性能。此外，与含有α-CD或γ-CD的类似聚合物相比，一种含有β-CD的StyDex聚合物在水性电解质中与全氟烷基酸（PFAA）和中性污染物表现出尺寸选择性的主客体相互作用。基于平均在21个可用羟基上随机分布七个苯乙烯基团的β-CD单体的聚合物，其性能与基于在七个6'位置进行区域特异性功能化的β-CD单体的聚合物相似。前一种β-CD单体由未改性的β-CD一步制备而成，因此在不影响性能的情况下使用它的能力为开发具有经济竞争力的吸附剂带来了希望。这些结果为StyDex聚合物的结构-吸附性能提供了重要见解，并将为改进的StyDex配方设计提供参考。
