Synergistic photocatalytic degradation of TC-HCl by Mn3+/Co2+/Bi2O3 and PMS

The widespread use of tetracycline hydrochloride (TC-HCl) poses a serious environmental problem and it is imperative to develop an effective method for its removal. Here, we prepared Mn3+/Co2+ co-doped Bi2O3 (MCBO) using a deposition-hydrothermal method to activate peroxymonosulfate (PMS). It was found that the degradation of TC-HCl was enhanced by the introduction of transition metal ions. The synergistic effect of photocatalysis and advanced oxidation based on peroxynitrite promoted the production of more reactive substances (e.g. O2−, OH, SO4−), which accelerated the degradation of TC-HCl. The effects of catalyst dosing, PMS concentration, pH and inorganic anions were also investigated and the catalyst/PMS/Vis system was found to have good removal performance in the pH range of 3–9 and the materials were structurally stable and reusable. The materials were characterized morphologically and structurally using XRD, XPS, SEM and UV–vis diffuse reflectance. Burst experiments showed that O2−, SO4− and OH all contributed to the degradation of TC-HCl. This work helps to provide a new direction for the design of green, efficient and recyclable catalysts to enhance the degradation of TC-HCl by synergistic photo-induced activation of PMS.