Efficient photocatalytic removal of four endocrine-disrupting compounds using N-doped BiOBr catalyst under UV-Vis radiation

Abstract A mixture of four endocrine-disrupting compounds (EDCs [17β-estradiol, 17α-ethinylestradiol, bisphenol A, and 4-tert-octylphenol]) was removed from aqueous solution using the N-doped BiOBr semiconductor (N = 10 and 20 wt%) easily prepared via microwave-assisted solvothermal synthesis. The N20BiOBr semiconductor showed the highest photocatalytic activity achieving the complete degradation of the EDCs, and 53.5% of mineralization in 240 min. Moreover, the toxicity of the mixture was reduced to moderate levels (from 90 to 47.5% of inhibition of the bioluminescence of V. fischeri). The high efficiency of N20BiOBr for EDCs removal was attributed to the increase of the specific surface area and the effective separation of photogenerated charges by effect of N incorporation. The main photogenerated species involved in the degradation of the pollutants were the superoxide radicals (O2•-) and photo-holes (h+), and a possible photocatalytic activation mechanism was proposed where suggests the active participation of oxygen vacancies. Additionally, N20BiOBr demonstrated excellent chemical and photocatalytic stability after four reuse cycles. Therefore, doping BiOBr with N constitutes a suitable and efficient strategy for the photocatalytic removal of a mixture of hazardous pollutants such as EDCs in water, with potential application in tertiary decontamination processes.