Oxygen vacancy assisted Mn-CuO Fenton-like oxidation of ciprofloxacin: Performance, effects of pH and mechanism

Abstract

Traditional Fenton reaction is limited by the problem of free radical scavenging and always requires pre-acidification, which seriously hinders its practical application. In this study, an oxygen vacancy (OVs) assisted Fenton-like catalyst (Mn-CuO) was designed to degrade ciprofloxacin (CIP). Results showed that Mn10CuO exhibited 3 times decomposition rate of H2O2 than that of CuO, and can make decent performances under a wide pH ranges (pH = 3.01–10.00). This can be ascribed to the Cu-Mn binary synergism and formation of OVs after addition of Mn2+, which not only improved the adsorption capacity of catalyst, but also promoted H2O2 activation. Moreover, different radical scavenging experiments and characterization shows that Cu(III) rather than ·OH dominated the degradation process in Mn10CuO/H2O2 system. The degradation intermediates were analyzed by LC-MS, and proposed the possible degradation pathways. Moreover, this system can work efficiently in tap water, river water as well as lake water without adjusting pH. This work indicates that it is an efficient strategy to constructing Fenton-like systems by using surface defect engineering to develop efficient catalyst.