Visible-light activation of peroxymonosulfate by NiCo2O4/Bi24O31Br10 to accelerate tetracycline degradation

The activation of peroxymonosulfate (PMS) by a bimetallic oxide, such as NiCo2O4, has attracted much attention from researchers because of its low energy and high stability. However, the application of the SR-Fenton-like system is limited by serious ion leaching. In this study, we synthesized a stable NiCo2O4/Bi24O31Br10 catalyst to efficiently degrade tetracycline in a PMS/visible light system. The 45% NiCo2O4/Bi24O31Br10 had remarkable degradation performance (90.3%) within 18 min. This was mainly due to the rapid transformation of Co2+/Co3+ and Ni2+/Ni3+ and enhancement in free radical production via Bi24O31Br10. The free radical capture experiment and electron spin resonance (ESR) results showed that SO4˙−/h+/HO˙/1O2 were the main active species in the tetracycline degradation. The cyclic experiment exhibited that the catalyst had high chemical stability. The possible degradation pathway of TCH was proposed. This study developed a stable and efficient PMS photo-activator for the treatment of wastewater.