CuFeS2 supported on dendritic mesoporous silica-titania for persulfate-assisted degradation of sulfamethoxazole under visible light

Tau S Ntelane; Usisipho Feleni; Nomcebo H Mthombeni; Alex T Kuvarega

doi:10.1016/j.jcis.2023.10.077

CuFeS₂ supported on dendritic mesoporous silica-titania for persulfate-assisted degradation of sulfamethoxazole under visible light

J Colloid Interface Sci. 2024 Jan 15;654(Pt A):660-676. doi: 10.1016/j.jcis.2023.10.077. Epub 2023 Oct 17.

Authors

Tau S Ntelane¹, Usisipho Feleni², Nomcebo H Mthombeni³, Alex T Kuvarega⁴

Affiliations

¹ Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, Florida, 1710 Johannesburg, South Africa; Department of Chemical Engineering, College of Science, Engineering and Technology, University of South Africa, Florida, 1710, Johannesburg, South Africa.
² Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, Florida, 1710 Johannesburg, South Africa.
³ Department of Chemical Engineering, College of Science, Engineering and Technology, University of South Africa, Florida, 1710, Johannesburg, South Africa; Department of Chemical Engineering, Faculty of Engineering and the Built Environment, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa.
⁴ Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, Florida, 1710 Johannesburg, South Africa. Electronic address: kuvarat@unisa.ac.za.

PMID: 37864871
DOI: 10.1016/j.jcis.2023.10.077

Abstract

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 CuFeS₂ supported on dendritic mesoporous silica-titania (CuFeS₂-DMST) photocatalyst was synthesized to improve the ability of TiO₂ to activate persulfate (PS) by introducing CuFeS₂ (Fe²⁺/Fe³⁺, Cu⁺/Cu²⁺ redox cycles). The CuFeS₂-DMST/PS/Vis system demonstrated superior SMX degradation efficiency (88.9%, 0.0146 min^-1) than TiO₂ because of reduced e^-/h⁺ recombination, excellent charge separation and mobility, and a greater surface area than TiO₂. Furthermore, after four consecutive photocatalytic cycles, the system demonstrated moderate stability. From chemical quenching tests, O₂^●-, h⁺, ¹O₂, SO₄^●- 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 TiO₂-based photocatalyst, and this concept can be applied to design photocatalysts for water treatment.

Keywords: Chalcopyrite; Sulfamethoxazole; Sulfate radicals. Advanced oxidation processes; TiO(2).