Highly efficient S-scheme AgBr/BiOBr with visible light photocatalytic performance for carbamazepine degradation: Mechanism insight and toxicity assessment

As more and more pharmaceutically active compounds (PhACs) have been found in the aquatic environment in recent years, the risks they pose to human health cannot be neglected. In this work, an innovative S-scheme AgBr/BiOBr photocatalyst for carbamazepine (CBZ) degradation was synthesized using a simple precipitation approach. XRD, SEM, XPS, UV–vis, PL, TPR, and EIS were employed to analyze the samples' crystal structure, morphology, chemical state, optical, and electrochemical properties. The effectiveness of the photocatalyst was also demonstrated through experiments, where a removal efficiency of 99.64 % was achieved under visible light for CBZ degradation using AgBr/BiOBr 10 wt%. Furthermore, photocatalytic cycling experiments, XRD characterization and cation exposure tests revealed that as-prepared photocatalysts had high reusability and stability. The intermediates were identified by HPLC-MS to reveal the possible degradation pathways of CBZ. The biological toxicity of CBZ and its degradation intermediates was also evaluated using the Vibrio fischeri luminescent bacteriological method and the toxicological calculation software. The findings of quenching experiments and ESR analyses indicated that ·O2− and h+ were the principal reactive species. The photoelectron transfer mechanism of AgBr/BiOBr photocatalyst was proposed as well. Overall, the synthesized photocatalysts are promising to provide a new insights into CBZ removal in the aqueous environment.