S-scheme TiO₂@In₂S₃/MIL-101(Cr) composite for dual-function removal of polystyrene microplastics and tetracycline in water

The progressive contamination of aquatic environments by microplastics and pharmaceutical residues has emerged as a pressing environmental issue. In the present study, a novel S-scheme TiO2@In2S3/ MIL-101(Cr) heterojunction composite was synthesized and evaluated for its capacity to simultaneously eliminate polystyrene microplastics (PSMPs) and tetracycline (TC) from aqueous media. The TiO2@In2S3/ MIL-101(Cr) composite exhibited outstanding photocatalytic and adsorptive properties, achieving complete removal of PSMPs (500 mg L-1) within 90 min and 97% removal of TC (30 mg L-1) within 210 min under visible-light irradiation. In a binary pollutant system, the composite enabled full elimination of both PSMPs and TC within 240 min, with PSMPs reaching 100% removal at 180 min and TC at 240 min. The superior performance was attributed to enhanced charge carrier separation and the suppression of electron-hole recombination, facilitated by the engineered heterojunction structure. Reusability tests confirmed the material's stability, with over 94% removal efficiency retained after four consecutive cycles. Moreover, adsorption experiments revealed a pronounced pH dependence, with optimal removal efficiency observed at pH 5. Collectively, these results highlight the dual functionality and robustness of TiO2@In2S3/MIL-101(Cr), underscoring its potential as a promising candidate for largescale water purification and environmental remediation applications. (c) 2026 Published by Elsevier B.V. on behalf of The Society of Powder Technology Japan.