Cation-Doped Nanocarbons for Enhanced Perfluoroalkyl Substance Removal: Exotic Bottom-Up Solution Plasma Synthesis and Characterization

Mongkol Tipplook; Kaoru Hisama; Michihisa Koyama; Kazunori Fujisawa; Fumitaka Hayashi; Tomohito Sudare; Katsuya Teshima

doi:10.1021/acsami.4c08925

Cation-Doped Nanocarbons for Enhanced Perfluoroalkyl Substance Removal: Exotic Bottom-Up Solution Plasma Synthesis and Characterization

ACS Appl Mater Interfaces. 2024 Sep 30. doi: 10.1021/acsami.4c08925. Online ahead of print.

Authors

Mongkol Tipplook¹, Kaoru Hisama¹, Michihisa Koyama¹, Kazunori Fujisawa¹, Fumitaka Hayashi², Tomohito Sudare¹, Katsuya Teshima^{1

2

3}

Affiliations

¹ Research Initiative for Supra-Materials (RISM), Shinshu University, Nagano 380-8553, Japan.
² Department of Materials Chemistry, Shinshu University, Nagano 380-8553, Japan.
³ Institute for Aqua Regeneration, Shinshu University, Nagano 380-8553, Japan.

PMID: 39348279
DOI: 10.1021/acsami.4c08925

Abstract

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^-1 of PFOS and PFOA, respectively, exceeding the efficiencies of conventional carbon-based adsorbents (80.89-313.15 mg g^-1). 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.

Keywords: perfluorooctanesulfonic acid (PFOS); perfluorooctanoic acid (PFOA); quaternary ammonium cation-doped carbon; solution plasma process; wastewater treatment.