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

Abstract

Given the limitations of conventional advanced oxidation processes (AOPs), a coupling system by integrating sulfate radical-based AOPs (SO4--AOPs) with photocatalysis for boosting the peroxymonosulfate (PMS) activation under visible light was established. Herein, we developed a novel 5 %Bi3O4Br/CuBi2O4 catalyst for rapid and efficient degradation of tetracycline (TC). The rate constant (k) for degrading TC in 5 %Bi3O4Br/CuBi2O4 + PMS + Vis system was 3.69 min−1, which is 30.62, 2.18 times higher than that of photocatalysis and SO4--AOPs alone, respectively. The quenching experiments verified that h+, OH, O2– and 1O2 were dominant contributors for the degradation of TC. EPR and quantitative analysis further implied illumination was favor in achieving mass production of OH and 1O2. Moreover, O2– and SO4- might convert into 1O2 in the 5 %Bi3O4Br/CuBi2O4 + 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 %Bi3O4Br/CuBi2O4 + 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.