Facile fabrication of TiO2/Bi5O7Br photocatalysts for visible-light-assisted removal of tetracycline and dye wastewaters

Abstract The emergence of persistent organic pollutants such as dyes and pharmaceuticals in the aquatic environment has created drastic concerns worldwide due to their toxicity and potential hazards to the environment. Accordingly, non-stoichiometric TiO 2 /Bi 5 O 7 Br nanocomposites were prepared by stirring method as a visible-light-effective photocatalyst for degradation of amoxicillin (AMX) and tetracycline (TC), as antibiotic pollutants, and rhodamine B (RhB), methylene blue (MB), and malachite green (MG), as dye pollutants. The physiochemical properties of the samples were studied using FESEM, TEM/HRTEM, XRD, EDX, UV–vis DRS, FT-IR, XPS, BET, PL, photocurrent, and EIS analyses. The TiO 2 /Bi 5 O 7 Br (40%) photocatalyst performed superior to TiO 2 , Bi 5 O 7 Br, and TiO 2 /BiOBr (40%) in photodegradation of the studied contaminants. The degradation rate constants of AMX, TC, MG, RhB, and MB over the TiO 2 /Bi 5 O 7 Br (40%) photocatalyst were 18.2‒32.5 folds greater than pure TiO 2 , 1.6‒17.3 times higher than pure Bi 5 O 7 Br, and 1.4‒13 times larger than TiO 2 /BiOBr (40%), respectively. Quenching studies showed that superoxide anion radicals and holes had major roles in photocatalytic elimination of TC. Importantly, TiO 2 /Bi 5 O 7 Br (40%) nanocomposite showed robust reusability with high degree of TC removal after four successive photocatalytic recycles. This research introduces a cost-effective, efficient, and reusable visible-light-triggered binary system based on TiO 2 for decontamination of medicinal and dye polluted wastewaters.