Exploring the origin of efficient adsorption of poly- and perfluoroalkyl substances in household point-of-use water purifiers: Deep insights from a joint experimental and computational study

• Published in: The Science of the total environment Vol. 831; p. 154988
• Main Authors: He, Anen, Lu, Yao, Chen, Fengjie, Li, Feifei, Lv, Kun, Cao, Huiming, Sun, Yuzhen, Liang, Yong, Li, Juan, Zhao, Lixia, Zhang, Xiang, Li, Lingxiangyu, Wang, Yawei, Jiang, Guibin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.07.2022
• Subjects: Adsorption; Computational chemistry; Environmental chemistry; Molecular mechanism; Poly- and perfluoroalkyl substances (PFAS); Poly- and perfluoroalkyl substances (PFAS); Environmental chemistry; Computational chemistry; Adsorption; Molecular mechanism
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.154988

Poly- and perfluoroalkyl substances (PFAS) are harmful chemicals to humans and widely detected in water bodies including tap water. PFAS cannot be efficiently removed from water through conventional treatment processes used in full-scale drinking water treatment plants, posing a latent risk to human health via drinking tap water. Here in-field investigations show that the household point-of-use (POU) water purifiers constituted with coconut shell activated carbon can achieve 21%–99% removal for 14 legacy and emerging PFAS in tap water based on the ratio of influent and effluent. Extensive characterizations combine with chemical analyses demonstrate that physical adsorption based on Van der Waals force can remove 23 PFAS from tap water, wherein the hydrophobicity of PFAS is the crucial factor. Density functional theory calculations together with the quantitative structure–activity relationship model confirm that both topological structures as well as hydrophobicity of PFAS and electrostatic interactions between the strong electronegative F atoms and the adsorbent surface are the most critical factors controlling the PFAS adsorption to activated carbon. Overall, our results offer insights into the molecular mechanisms that enable the adsorption of PFAS in POU filters. [Display omitted] •PFAS in tap water are efficiently removed in household point-of-use water purifiers.•The PFAS removal is mainly due to physical adsorption via Van der Waals forces.•DFT and QSAR provide insights into adsorption mechanisms at molecular level.•Electrostatic attraction and hydrophobicity are critical factors for PFAS adsorption.