Lower Critical Solution Temperature-Driven Catch and Release of Perfluoroalkyl Substances from Water: Remediation and Sampling
Lower Critical Solution Temperature-Driven Catch and Release of Perfluoroalkyl Substances from Water: Remediation and Sampling
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DOI：
10.1021/acsapm.1c00608
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发表时间：
2021-08
影响因子：
5
通讯作者：
M. Ezazi;Bishwas Shrestha;Gibum Kwon
中科院分区：
文献类型：
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作者：
M. Ezazi;Bishwas Shrestha;Gibum Kwon
全氟烷基和多氟烷基物质（PFASs）对水的污染是一个日益严重的环境和人类健康问题，因为PFASs具有持久性和不可生物降解性。最近的研究表明，在受污染的水中发现的PFAS的浓度约为万亿分之几（即，10-12）规模。这可能会给科学家带来巨大的挑战，不仅要从水中去除PFAS，还要检测它们。各种方法，包括功能化的纳米粒子，生物测定，活性炭，阴离子交换树脂，和分子印迹聚合物已被用来检测或去除PFASs从水中。动态吸附剂已经证明，它们可以从水中吸附PFAS，同时在外部触发下按需释放PFAS以重新使用。这使得人们能够从水中去除PFAS并保留它们进行预浓缩，而按需释放则允许再生吸附剂以重复使用。本文中，报道了一种基于聚（异丙基甲基丙烯酰胺）（P-NIPMAM）的吸附剂，其可以在高于其低临界溶解温度（LCST）的温度下吸附和保留PFAS，同时在较低温度下释放PFAS。全氟辛酸（PFOA）和全氟己酸（即，PFHxA）分别用作具有长和短氟烷基链的代表性PFAS。在75 °C时，PFOA和PFHxA的吸附容量分别为1037和1018 mg g-1。当吸附剂浸入较低温度的水中时（例如，23 °C < LCST）时，开始释放被吸附的化合物，导致PFOA和PFHxA的解吸效率分别为0.66和0.81。最后，利用P-NIPMAM设计了一个原型PFAS采样器，可以演示LCST驱动的PFASs可逆吸附和解吸。
Water pollution by per- and polyfluoroalkyl substances (PFASs) is a rising issue for the environment and human health because PFASs are persistent and nonbiodegradable. Recent studies have revealed that the concentration of PFASs found in contaminated water is in the order of the parts per trillion (i.e., 10–12) scale. This can result in a grand challenge for scientists not only to remove PFASs from water but to detect them. Various methodologies including functionalized nanoparticles, bioassay, activated carbon, anion exchange resin, and molecularly imprinted polymers have been employed to detect or remove PFASs from water. Dynamic adsorbents have demonstrated that they can adsorb PFASs from water while releasing them on demand for reuse upon an external trigger. This enables one to remove PFASs from water and retain them for preconcentration, while on-demand releasing allows for regenerating the adsorbent for reuse. Herein, a poly(isopropylmethacrylamide) (P-NIPMAM)-based adsorbent that can adsorb and retain PFASs at a temperature higher than its lower critical solution temperature (LCST) while releasing them at a lower temperature is reported. Perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (i.e., PFHxA) are utilized as a representative PFAS with a long and short fluoroalkyl chain, respectively. The adsorption capacity for PFOA and PFHxA is measured as ≈37 and ≈18 mg g–1at 75 °C, respectively. When the adsorbent is submerged in water at a lower temperature (e.g., 23 °C < LCST), it starts to release the adsorbed compounds resulting in the desorption efficiency of ≈0.66 and ≈0.81 for PFOA and PFHxA, respectively. Finally, a prototype PFAS sampler was engineered by utilizing P-NIPMAM that can demonstrate the LCST-driven reversible adsorption and desorption of PFASs.