Effect of clay mineral support on photocatalytic performance of BiOBr-TiO2 for efficient photodegradation of xanthate

Modulating the activity of semiconducting photocatalysts by altering their support properties is an appealing strategy for strengthening the photocatalytic reactions. In this study, BiOBr-TiO2 (BT) semiconducting composites were synthesized and loaded on the pretreated attapulgite, montmorillonite, and diatomite supports, which were then optimized and labeled as BTA-300, BTM-400, and BTD-300, respectively. Xanthates were utilized as the target contaminants to assess the catalyst performance of the composite photocatalysts due to their high toxicity and extensive application in the mineral processing industry. It was revealed that the clay mineral supports had a great regulatory effect on the activity of BT photocatalysts in the xanthates photodegradation process under visible light. The reaction rate constant for the BTA-300 photocatalysts in the degradation of 20 mg/L sodium ethyl xanthate (SEX) was 0.108 min−1, exhibiting 1.55 and 1.41 times higher than that of BTM-400 and BTD-300, correspondingly. The inherent properties of the support clay minerals enhanced the activity of photo-excited carriers by influencing their migration and recombination, and thereby affected the photocatalytic activity. This study deduced potential molecular degradation pathways for SEX and analyzed the developmental toxicity and mutagenicity of the intermediates, which provides a valuable reference for future industrial applications.