Nanotechnology in remediation of water contaminated by poly- and perfluoroalkyl substances: A review

This article gives an overview of nanotechnologies applied in remediation of water contaminated by poly- and perfluoroalkyl substances (PFASs). The use of engineered nanomaterials (ENMs) in physical sorption and photochemical reactions offers a promising solution in PFAS removal because of the high surface area and the associated high reactivities of the ENMs. Modification of carbon nanotubes (CNTs) (e.g., oxidation, applying electrochemical assistance) significantly improves their adsorption rate and capacity for PFASs removal and opens a new door for use of CNTs in environmental remediation. Modified nanosized iron oxides with high adsorption capacity and magnetic property have also been demonstrated to be ideal sorbents for PFASs with great recyclability and thus provide an excellent alternative for PFAS removal under various conditions. Literature shows that PFOA, which is one of the most common PFASs detected at contaminated sites, can be effectively decomposed in the presence of either TiO2-based, Ga2O3-based, or In2O3-based nano-photocatalysts under UV irradiation. The decomposition abilities and mechanisms of different nano-photocatalysts are reviewed and compared in this paper. Particularly, the nanosized In2O3 photocatalysts have the best potential in PFOA decomposition and the decomposition performance is closely related to the specific surface area and the amount of photogenerated holes on the surfaces of In2O3 nanostructures. In addition to detailed review of the published studies, future prospects of using nanotechnology for PFAS remediation are also discussed in this article. Published by Elsevier Ltd.