Dye-sensitization on rosette-shaped BiOBr/Biochar photocatalyst for simultaneous removal of emerging pollutants and dyes

Abstract

This study presents the fabrication of rosette-shaped bismuth oxybromide/biochar (BiOBr/BC) photocatalysts supported on biochar via a straightforward solvothermal approach. This BiOBr/BC photocatalyst demonstrates remarkable efficiency in degrading 17α-ethinylestradiol (EE2). The incorporation of the photosensitizer Rhodamine B (RhB) significantly enhances the degradation rate of EE2, while RhB itself undergoes degradation during visible-light photocatalysis. Biochar serves as a substrate, offering several advantages such as improved adsorption, facilitated electron transfer, and increased production of free radicals, all contributing to the enhanced degradation of EE2 by BiOBr/BC. Under 20 min of visible light irradiation, the degradation rate of EE2 by the RhB-sensitized BiOBr/BC system reaches 99.28%. Furthermore, the incorporation of RhB improves the stability and recyclability of the BiOBr/BC system, maintaining an EE2 degradation rate of 92.00% after seven consecutive degradation cycles. Our photocatalytic system exhibits strong degradation activity towards a mixed-pollutant solution of EE2 and various dyes. LC-MS analysis identified the degradation products and computational predictions indicated their lower ecotoxicity compared to the parent compound. Overall, this study provides new insights and possibilities for the treatment of environmental pollutants, leveraging the concept of “curing waste with waste”.