Sunlight-activated BiOCl/BiOBr-Bi24O31Br10 photocatalyst for the removal of pharmaceutical compounds

Herein, the degradation of fluoroquinolones was investigated. In this regard, 3D-flower-like BiOCl/BiOBr-Bi24O31Br10 type-II nanoheterojunctions were fabricated using sono-assisted solvothermal and introduced as an effectual sunlight-activated photocatalyst for the removal of pharmaceuticals from effluents and polluted surface water. To evaluate the effect of each component in the degradation of levofloxacin, ofloxacin, norfloxacin and ciprofloxacin, the BiOCl(x)/BiOBr-Bi24O31Br10(y) photocatalysts with different values of x/y = 75/25, 50/50 and 25/75 were fabricated. X-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscopy, energy dispersive X-ray and elemental mapping, Brunauer-Emmett-Teller and the Barrett-Joyner-Halenda and diffuse reflectance were employed to characterize the nanophotocatalysts. The results illustrated that, BiOCl(25)/BiOBr-Bi24O31Br10(75) type-II nanoheterojunction represented the best photocatalytic performance in the removal of 50 mg/L levofloxacin (80.2%) and 50 mg/L ofloxacin (78.3%). This could be attributed to the suitable band gap, enhanced light harvest, more effective separation of photo-generated electron-hole pairs and reducing their recombination, improving the phenomenon of mass transfer and increasing the adsorption capacity. Finally, the stability of BiOCl(25)/BiOBr-Bi24O31Br10(75) type-II nanoheterojunction was appraised in four cycles and a mechanism for the photo-destruction of antibiotic was proposed. (C) 2020 Elsevier Ltd. All rights reserved.