Amine-Functionalized A-Center Sphalerite for Selective and Efficient Destruction of Perfluorooctanoic Acid

Abstract

Perfluorochemicals (PFCs), especially perfluorooctanoic acid (PFOA), have contaminated the ground and surface waters throughout the world. Efficient removal of PFCs from contaminated waters has been a major challenge. This study developed a novel UV-based reaction system to achieve fast PFOA adsorption and decomposition without addition of sacrificial chemicals by using synthetic photocatalyst sphalerite (ZnS-[N]) with sufficient surface amination and defects. The obtained ZnS-[N] has the capability of both reduction and oxidation due to the suitable band gap and photo-generated hole-trapping properties created by surface defects. The cooperated organic amine functional groups on the surface of ZnS-[N] play a crucial role in the selective adsorption of PFOA, which guarantee the efficient destruction of PFOA subsequently, and 1 μg L–1 PFOA could be degraded to <70 ng L–1 after 3 h in the presence of 0.75 g L–1 ZnS-[N] under 500 W UV irradiation. In this process, the photogenerated electrons (reduction) and holes (oxidation) on the ZnS-[N] surface work in a synergistic manner to achieve complete defluorination of PFOA. This study not only provides promising green technology for PFC-pollution remediation but also highlights the significance of developing a target system capable of both reduction and oxidation for PFC degradation.

Efficient Decomposition of Perfluoroalkyl Substances by Low Concentration Indole: New Insights into the Molecular Mechanisms

“…Per- and polyfluoroalkyl substances (PFAS) have caused global pollution due to their massive production and application since the 1940s. − Among these PFAS, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) are the two most concerned compounds with the highest environmental background concentrations, and both of them have been listed in the Stockholm convention . Moreover, due to its strong environmental persistence and ecological toxicity, PFAS pollution has had a seriously negative impact on animal and human health. − Nowadays, carbon materials, ion-exchange resins, and some advanced functional materials have been developed to capture PFAS from polluted water, − while the subsequent decomposition treatment of the concentrated PFAS remains challenging …”