Boosting reactive oxygen species generation over Bi3O4Br/CuBi2O4 by activating peroxymonosulfate under visible light irradiation

Given the limitations of conventional advanced oxidation processes (AOPs), a coupling system by integrating sulfate radical-based AOPs ( SO 4 - -AOPs) with photocatalysis for boosting the peroxymonosulfate (PMS) activation under visible light was established. Herein, we developed a novel 5 %Bi 3 O 4 Br/CuBi 2 O 4 catalyst for rapid and efficient degradation of tetracycline (TC). The rate constant (k) for degrading TC in 5 %Bi 3 O 4 Br/CuBi 2 O 4  + PMS + Vis system was 3.69 min −1 , which is 30.62, 2.18 times higher than that of photocatalysis and SO 4 - -AOPs alone, respectively. The quenching experiments verified that h + , OH, O 2 – and 1 O 2 were dominant contributors for the degradation of TC. EPR and quantitative analysis further implied illumination was favor in achieving mass production of OH and 1 O 2 . Moreover, O 2 – and SO 4 - might convert into 1 O 2 in the 5 %Bi 3 O 4 Br/CuBi 2 O 4  + PMS + Vis system. The degradation pathways of TC were proposed and the toxicity of intermediates was much lower than that of untreated TC. Besides, the 5 %Bi 3 O 4 Br/CuBi 2 O 4  + PMS + Vis system showed over 90% removal rate in a wide pH range (3–11) or different concentrations of inorganic anions. This work provided a worthy reference in developing an environmentally-friendly system for the high-efficiency degradation of antibiotics.