Insight into combining visible-light photocatalysis with transformation of dual metal ions for enhancing peroxymonosulfate activation over dibismuth copper oxide

The widespread use of pharmaceuticals and personal care products (PPCPs) is posing serious environmental issues, and it is imperative to develop an effective treatment for removing PPCPs. Herein, we used a binary metal oxide of dibismuth copper oxide (CuBi2O4) to activate peroxymonosulfate (PMS) for removing PPCPs. Interestingly, above system was evidently improved by introducing visible light. Photocatalysis and the synchronous transformations of Bi3+/Bi5+ and Cu2+/Cu+ valence states over CuBi2O4 are combined organically. Such a synergistic effect promotes the production of more active species (e.g., O-1(2), h(+), center dot OH, SO4 center dot-) for further resulting in the rapid degradation of PPCPs. Taking tetracycline (TC) degradation as a model, the detailed degradation pathways of TC and the toxicity of degraded products were identified. This work not only provides a facile yet effective catalytic reaction system for removing PPCPs, but also gives some further insights to understand the reaction mechanism involving Bi-based or other like binary metal oxidative materials.