Novel recyclable composite BiOBr/chitin-Fe3O4 with enhanced visible-light photocatalytic degradation of the antibacterial agent ciprofloxacin

In this study, novel recyclable composite BiOBr/chitin-Fe3O4 was synthesized by a solvothermal method using magnetic chitin chelating bismuth oxybromide (BiOBr) as precursor. The morphology, structure, photoelectric properties and chemical composition of the obtained samples were explored extensively by various characterization techniques. Due to the introduction of Fe3O4 and chitin, the composite BiOBr/chitin-Fe3O4 has multi-functions in enlarging photo response performance, reducing the band gap, increasing specific surface area and inhibiting recombination rate, which are essen-tial to improve the photocatalytic efficiency. Using ciprofloxacin as target pollutant, the composite showed excellent photocatalytic performance under visible light irradiation, the apparent rate con-stant value of BiOBr/chitin-Fe3O4 is 5.8 times higher than that of pure BiOBr. The composite BiOBr/ chitin-Fe3O4 could be recycled and reused conveniently and effectively, and the catalyst possessed good photocatalytic stability with the degradation efficiency remaining unchanged even after five times circle. The possible degradation mechanism was discussed on the basis of experiments.