Surfactant-Modified Clay for Adsorption of Mixtures of Per- and Polyfluoroalkyl Substances (PFAS) in Aqueous Solutions
Surfactant-Modified Clay for Adsorption of Mixtures of Per- and Polyfluoroalkyl Substances (PFAS) in Aqueous Solutions
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DOI：
10.1021/acsaenm.2c00096
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
Tao Jiang;Weilan Zhang;Aswin Kumar Ilango;Jeremy I. Feldblyum;Zheng Wei;H. Efstathiadis;M. Yigit
中科院分区：
文献类型：
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作者：
Tao Jiang;Weilan Zhang;Aswin Kumar Ilango;Jeremy I. Feldblyum;Zheng Wei;H. Efstathiadis;M. Yigit
全氟烷基和多氟烷基物质（PFAS）是持久性、生物累积性和普遍存在的污染物，对人类和生态系统健康都有害。为了有效去除水中的PFAS，采用阳离子表面活性剂十六烷基三甲基氯化铵（CTAC）对蒙脱土进行改性，制备了一种粘土基吸附剂。通过有机染料和PFAS混合物的共暴露吸附试验，确定了CTAC与阳离子交换容量（CEC）的最佳比例。最佳的改性粘土表现出显着改善的吸附性能，实现100%的PFAS混合物的去除效率，包括九个短链和长链PFAA，GenX，和三个前体在初始浓度的十亿分之一（ppb）的水平。此外，改性粘土在吸附性能方面优于其他商业吸附剂。所有PFAS的吸附动力学数据，这是很好地描述的伪二级模型，表明一个快速的吸附过程和依赖于初始浓度和碳链长度的吸附行为。在三个考察的吸附等温线，Sips模型结合Langmuir和Freundlich模型表现出最好的拟合相关性，表明在吸附过程中可能涉及到多重相互作用。这一假设得到了表征的支持，表明改性粘土具有有利于静电相互作用和疏水相互作用的物理化学性质。
: Per-and polyfluoroalkyl substances (PFAS) are persistent, bioaccumulative, and ubiquitous contaminants that are harmful to both humans and ecosystem health. To remove PFAS effectively and efficiently from the aqueous environment, a clay-based adsorbent was synthesized via the modification of montmorillonite by a cationic surfactant cetyltrimethylammonium chloride (CTAC). Through the coexposure adsorption tests with organic dyes and PFAS mixtures, the optimal ratio of CTAC to cation exchange capacity (CEC) was identified. The optimal modified clay exhibited drastically improved adsorption performance, achieving 100% removal efficiency of the PFAS mixture consisting of nine short-and long-chain PFAAs, GenX, and three precursors at initial concentrations of the parts per billion (ppb) level. Additionally, the modified clay outperformed other commercial adsorbents with respect to adsorption performance. The adsorption kinetic data of all PFAS, which were well described by the pseudo-second-order model, suggested an expeditious adsorption process and an adsorption behavior dependent on the initial concentration and carbon chain length. Among the three examined adsorption isotherms, the Sips model combining Langmuir and Freundlich models showed the best fitting correlation, indicating that multiple interactions might be involved in the adsorption process. This hypothesis was supported by characterizations showing that the modified clay possessed physicochemical properties favorable for electrostatic interactions and hydrophobic interactions.