Novel approach for preparation of three-dimensional BiOBr/BiOI hybrid nanocomposites and their removal performance of antibiotics in water

[Display omitted] •A novel solvothermal reduction-ion exchange method was proposed to prepare BiOBr/BiOI photocatalyst.•A blooming Peony-like BiOBr/BiOI photocatalyst was prepared.•The material showed high degradation and mineralization ability for levofloxacin in water.•Holes oxidation was the main photocatalytic mechanism. Herein, a blooming flower-like BiOBr/BiOI was fabricated via solvothermal reduction-ion exchange method and its photocatalytic performance was evaluated by the photocatalytic degradation of levofloxacin hydrochloride in water under visible light irradiation. Morphology, structure, optical properties and some of the underling mechanism were revealed by multifarious characterization techniques, photoelectrochemical measurements, and active substances capture. It was shown that BiOBr/BiOI composite (S6) with molar ratio of 12:1 (BiOBr to BiOI) displayed higher photocatalytic efficiency than pristine BiOBr, BiOI and the composites at other molar ratios. The degradation efficiency of levofloxacin hydrochloride over the optimized composite reached 97 % in 120 min, and even 75.9 % mineralization rate was achieved in 180 min. However, the degradation efficiency was only 48.4 % and 2 % over pristine BiOBr and BiOI, respectively. The enhancement of photocatalytic activity was attributed to the effective separation of photoexcited electron-hole carriers by the formation of BiOBr/BiOI heterojunction. Holes were proved to be the primary active ingredients that degraded levofloxacin hydrochloride. The strategies proposed in this work provide new ideas and methods for the preparation of other related materials and efficient removal of levofloxacin hydrochloride in wastewater.