CuFeS supported on dendritic mesoporous silica-titania for persulfate-assisted degradation of sulfamethoxazole under visible light.

Sulfamethoxazole (SMX) is a prevalent sulfonamide antibiotic found in the environment, and it has a variety of detrimental effects on environmental sustainability and water safety. Recently, the combination of photocatalysis and sulfate radical-based advanced oxidation processes (SR-AOPs) has attracted a lot of interest as a viable technique for degradation of refractory pollutants. In this study, a visible light active CuFeS supported on dendritic mesoporous silica-titania (CuFeS-DMST) photocatalyst was synthesized to improve the ability of TiO to activate persulfate (PS) by introducing CuFeS (Fe/Fe, Cu/Cu redox cycles). The CuFeS-DMST/PS/Vis system demonstrated superior SMX degradation efficiency (88.9%, 0.0146 min) than TiO because of reduced e/h recombination, excellent charge separation and mobility, and a greater surface area than TiO. Furthermore, after four consecutive photocatalytic cycles, the system demonstrated moderate stability. From chemical quenching tests, O, h, O, SO and OH were found to be the main reactive oxidizing species. The formed intermediates during the degradation process were identified, and degradation mechanisms were proposed. This study proposes a viable technique for activating PS using a low-cost, stable, and high-surface-area TiO-based photocatalyst, and this concept can be applied to design photocatalysts for water treatment.