Efficient degradation of ciprofloxacin by Cu2O/g-C3N4 heterostructures with different morphologies driven under the visible light

In this study, Cu2O/g-C3N4 composite with photocatalytic activity was successfully prepared by chemical precipitation method. The catalytic degradation of ciprofloxacin (CIP) by Cu2O and Cu2O/g-C3N4 composites with different morphologies was investigated. The effective structure and properties of Cu2O/g-C3N4 composites were tested by a series of characterization methods. The photocatalytic test results show that the Cu2O/g-C3N4 composite photocatalyst has good stability and good photocatalytic performance, which is attributed to the effective hetero-junction structure formed by the combination of Cu2O and g-C3N4, which promotes the interfacial charge separation. The addition of g-C3N4 can reduce the crystal size of Cu2O, improve the crystal morphology, and increase its light utilization. Among the synthesized catalysts, the Cu2O-3(20%)/g-C3N4 composite has the highest catalytic activity, and the photocatalytic oxidation efficiency of CIP is 96%. By free radical capture and ESR analysis, it was verified that OH, h+ and O2− radicals may be the main active substances involved in CIP photodegradation. Finally, various degradation products and intermediates of CIP were identified by LC-MS, and the possible conversion pathways were proposed.