Tipplook Mongkol, Hisama Kaoru, Koyama Michihisa, Fujisawa Kazunori, Hayashi Fumitaka, Sudare Tomohito, Teshima Katsuya
Research Initiative for Supra-Materials (RISM), Shinshu University, Nagano 380-8553, Japan.
Department of Materials Chemistry, Shinshu University, Nagano 380-8553, Japan.
ACS Appl Mater Interfaces. 2024 Nov 13;16(45):61832-61845. doi: 10.1021/acsami.4c08925. Epub 2024 Sep 30.
Perfluorinated alkyl substances (PFAS), such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are pervasive organic contaminants that are widespread in aquatic environments, posing significant health risks to humans and wildlife. Due to their persistent nature, urgent removal is necessary. Conventional adsorbents are inefficient at removing PFOS and PFOA, highlighting the need for alternative materials. Herein, we present a synthetic method for quaternary ammonium cation-doped carbon nanoparticles (QACNs) using a solution plasma process for the efficient removal of PFOS and PFOA. QACN is formed simultaneously through a one-step discharge of nonequilibrium plasma at the interface of benzene and pyridinium chloride. The resulting material exhibited a high surface electrical charge and enhanced hydrophilicity as well as an amorphous structure of a nonporous nature, involving nanoparticles with an undefined shape. The obtained adsorbent demonstrated high adsorption efficiency and stability, adsorbing 998.45 and 889.37 mg g of PFOS and PFOA, respectively, exceeding the efficiencies of conventional carbon-based adsorbents (80.89-313.15 mg g). The adsorption performance was dependent on the adsorbent dosage, pH of the solution, and the coexisting ionic species. Adsorption studies, including adsorption kinetics, isotherms, and thermodynamics, revealed that PFOS and PFOA were chemisorbed to the QACN surface, forming multilayers endothermically and spontaneously. Experimental and computational analyses revealed that adsorption primarily occurs via electronic interactions between the PFAS active sites and the quaternary ammonium group in the carbon framework. The slightly lower adsorption potential of the PFOS and PFOA fluorocarbon chains on the adsorbent was elucidated. Furthermore, the dispersibility of the adsorbent in solution significantly affected the adsorption performance. These findings highlight the potential of the novel synthetic method proposed in this study, offering a pathway for the development of highly effective carbon adsorbents for environmental remediation.
全氟烷基物质（PFAS），如全氟辛烷磺酸（PFOS）和全氟辛酸（PFOA），是普遍存在的有机污染物，广泛存在于水生环境中，对人类和野生动物构成重大健康风险。由于它们的持久性，迫切需要将其去除。传统吸附剂在去除PFOS和PFOA方面效率低下，这凸显了对替代材料的需求。在此，我们提出了一种使用溶液等离子体工艺合成季铵阳离子掺杂碳纳米颗粒（QACN）的方法，用于高效去除PFOS和PFOA。QACN是通过在苯和氯化吡啶界面处一步放电非平衡等离子体同时形成的。所得材料表现出高表面电荷和增强的亲水性，以及无定形的非多孔结构，包含形状不确定的纳米颗粒。所制备的吸附剂显示出高吸附效率和稳定性，分别吸附998.45和889.37 mg/g的PFOS和PFOA，超过了传统碳基吸附剂的效率（80.89 - 313.15 mg/g）。吸附性能取决于吸附剂用量、溶液pH值和共存离子种类。吸附研究，包括吸附动力学、等温线和热力学，表明PFOS和PFOA通过化学吸附作用于QACN表面，多层吸热且自发形成。实验和计算分析表明，吸附主要通过PFAS活性位点与碳骨架中的季铵基团之间的电子相互作用发生。阐明了PFOS和PFOA碳氟链在吸附剂上吸附潜力略低的原因。此外，吸附剂在溶液中的分散性显著影响吸附性能。这些发现突出了本研究中提出的新型合成方法的潜力，为开发用于环境修复的高效碳吸附剂提供了一条途径。
