Highly Conductive Ti3c2 Mxene Reinforced G-C3n4 Heterojunction Photocatalytic for the Degradation of Ciprofloxacin: Mechanism Insight

Abstract

The extensive use of ciprofloxacin (CIP) poses a great threat to aquatic ecosystem, due to its potentially serious inhibitory effect on the microbial activity and low natural degradation rate. Photocatalytic degradation has emerged as a feasible method for treating CIP pollution. In this study, Ti3C2 reinforced g-C3N4 heterojunction material (MX/CN) was prepared using solvent drying method. The heterojunction composite accelerated the electron transfer rate, and the resulting MX/CN exhibited superior photocatalytic activity against CIP under visible light driving. The MX/CN sample achieved higher CIP photocatalytic removal rate of 97.8%, 1.23 times higher than CN. Moreover, 6%-MX/CN showed the best photocatalytic activity at pH=7 when the initial concentration of CIP was 10 mg/L. Under neutral condition, the presence of Cl-, NO3-, and HCO3- reduced the degradation of CIP, where the addition of HCO3- caused a competed redox reaction with •OH in the system, resulting in a reduction of the CIP degradation efficiency to 30.9%. The photocatalytic mechanism involving MX/CN was proposed according to the trapping experiments of active species, which confirmed that •O2- was the primary active component in photocatalytic degradation of CIP and h+ and •OH also played significant roles. Finally, cycling experiments using MX/CN showed that the CIP degradation efficiency more than 90% was maintained after five cycles.

Keywords: MXene/g-C3N4heterojunction, photocatalysis, Degradation, Ciprofloxacin