Per- and poly-fluoroalkyl substances (PFAS) constitute a class of persistent organic pollutants that severely affect human health and the environment owing to their resistance to degradation by traditional water treatment methods. Semiconductor-assisted photocatalysis has the potential to be a green method to achieve complete mineralization of PFAS. Cadmium indium sulfide (CdIn2S4) is an exciting photocatalytic material because of its high visible light harvesting capacity and high reduction potential. However, CdIn2S4 has not been investigated for PFAS degradation. Herein, CdIn2S4 micro-pyramids are fabricated via solvothermal synthesis, and their photocatalytic activity toward the photodegradation of perfluorooctanesulfonic acid (PFOS) is investigated. The reaction conditions, such as the light source and the light power are optimized. The findings show the capability of CdIn2S4 to achieve almost complete degradation and defluorination of PFOS (removal% = 99 ± 7% and defluorination% = 97 ± 22%) under optimized conditions. From radical quenching experiments, it is found that the mechanism of degradation is via photoelectron reduction. CdIn2S4 shows an outstanding performance toward the degradation of the PFAS sample derived from a contaminated facility in South Australia. This work opens the door for investigating other CdIn2S4-based photocatalysts and other metal sulfide-based photocatalysts for the degradation of PFAS. 

For more information: https://doi.org/10.1002/smll.202504601