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

Abstract

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.