Photodegradation of ciprofloxacin antibiotic in water by using ZnO-doped g-CN photocatalyst.

Ciprofloxacin antibiotic (CIP) is one of the antibiotics with the highest rate of antibiotic resistance, if used and managed improperly, can have a negative impact on the ecosystem. In this research, ZnO modified g-CN photocatalyst was prepared and applied for the decomposition of CIP antibiotic compounds in water. The removal performance of CIP by using ZnO/g-CN reached 93.8% under pH 8.0 and an increasing amount of catalyst could improve the degradation performance of the pollutant. The modified ZnO/g-CN completely oxidized CIP at a low concentration of 1 mg L and the CIP removal efficiency slightly decreases (around 13%) at a high level of pollutant (20 mg L). The degradation rate of CIP by doped sample ZnO/g-CN was 4.9 times faster than that of undoped g-CN. The doped catalyst ZnO/g-CN also displayed high reusability for decomposition of CIP with 89.8% efficiency remaining after 3 cycles. The radical species including ·OH, ·O and h are important in the CIP degradation process. In addition, the proposed mechanism for CIP degradation by visible light-assisted ZnO/g-CN was claimed.