Facile fabrication of CeO2/L-Bi2O2CO3 composite photocatalyst for removal of ciprofloxacin under visible light irradiation

Abstract

The application of semiconductor photocatalytic technology to degrade antibiotics in water has been proved to be a promising technology CeO2/L-Bi2O2CO3 composite photocatalyst was efficiently prepared by a facile room temperature precipitation technique and employed in the photocatalytic degradation of ciprofloxacin (CIP). When the concentration of ciprofloxacin was 20 mg/L and the dosage of catalyst was 1.0 g/L, the degradation rate of CIP was 89.96 % after 120 min reaction with optimal catalyst. The addition of L-cysteine not only changed the crystallinity of Bi2O2CO3, but also broadened its visible light absorption range. Additionally, the combination of CeO2 and L-Bi2O2CO3 creates a heterojunction interface accelerates the electron transfer, thereby improving the photocatalytic activity. The degradation process was confirmed to involve the significant participation of O2– and h+ through free radical capture experiments. HPLC-MS analysis detected the intermediates of CIP degradation, leading to the proposition of two potential degradation pathways. Moreover, an electron transfer mechanism was suggested by analyzing the Mott-Schottky (M−S) curve and Taut-plot curves. This work provides new paradigm for the rational design of modified Bi2O2CO3-based photocatalysts and the treatment of contain CIP wastewater.