Efficient photocatalytic activation of peroxydisulfate by oxygen vacancy-rich NiFe2O4 for rapid degradation of tetracycline hydrochloride

Water pollution has become an increasingly serious global problem. The types of organic pollutants in water bodies are becoming more and more complex and diversified, which brings great challenges to environmental protection. In this paper, oxygen vacancy-rich nickel ferrite (NiFOV) was simply prepared by two methods (hydrothermal and calcination). The synergic effect of photocatalysis and peroxydisulfate (PDS) on the degradation of tetracycline hydrochloride (TCH) by NiFOV was studied. The results showed that NiFOV displayed excellent catalytic activity, the efficiency of degrading TCH within 60 min reached 87.4 %. In addition, NiFOV showed good stability and reusability, maintaining a degradation rate of 78.3 % after 4 cycles. Radical capture and electron paramagnetic resonance (EPR) experiments showed that possible degradation pathways included free radical pathway and non-free radical pathway, in which SO4 center dot(-), O-1(2), h(+) and center dot OH played important roles. The presence of oxygen vacancies significantly increased the specific surface area of the catalyst, enhanced the adsorption capability of O-2 and promoted the utilization of visible light and the activation of PDS. This study provides a new understanding of PDS activation based on ferrite defect engineering and has a good application prospect.