A case study of different bismuth oxyhalides BiOX (X = F, Cl, Br, and I)/biochar-derived rice husk@graphitic carbon nitride for the robustness of H2O2 photoproduction and antibiotic photodegradation

In this study, the heterojunction photocatalyst bismuth oxyhalides/rice husk-derived biochar@graphitic carbon nitride (BiOX (X = F, Cl, Br, and I)/BC@CN) was successfully synthesized through calcination and hydrothermal self-assembly synthesis. The photo-absorption range of CN was expanded by coupling of biochar and BiOX, which also improved electron production and increased the number of active sites for O2 and H+ adsorption. This structure modification produced good H2O2 production performance with the H2O2 photoproduction of BiOI/BC@CN reaching 2.89 mM·g−1 under visible light illumination. Besides, the highest photodegradation of ciprofloxacin (CIP) of BiOBr/BC@CN was given at pH 7.5, catalyst dose 30 mg, and CIP concentration 20 mg·L−1 (99.79 %), in which the photodegradation kinetics followed the pseudo-first-order model with a rate constant of 0.03098 min−1. This work provides an innovative and practical modification method that utilizes agricultural by-products from rice husks to promote the advancement of semiconducting catalysts in the photo-activities of H2O2 generation and antibiotic removal.