An insight into mimic of photo-Fenton degradation of ciprofloxacin and tetracycline

A robust Zn-BTC MOF photocatalyst deposited with varying concentrations of graphene oxide was successfully prepared using an in-situ solvothermal method and named GO@ZnMC. X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and other techniques were used to characterize the phase component, microstructure, and optical properties of the catalysts. The photocatalytic performance of the GO@ZnMC composite was tested by degrading the antibiotics ciprofloxacin (CIP) and tetracycline (TC) with the help of hydrogen peroxide (H2O2) or calcium peroxide (CaO2) under visible light irradiation. The degradation efficiency for CIP and TC is more with CaO2 compared to H2O2 by virtue of CaO2 continuously producing H2O2. The degradation rate of the GO@ZnMC3 composite is higher when compared to that of pristine GO, Zn-MOF, and other composites. The increased photocatalytic activity is attributed to the formation of heterojunction that effectively suppresses electron-hole pair recombination. Introducing H2O2 or CaO2 encourages the formation of more active reactive oxygen species (ROS), specifically OH•, as confirmed by radical scavenging experiments, showing that the degradation reaction mimics the photo-Fenton reaction. A possible photocatalytic degradation mechanism is also proposed with the help of the LC-MS analysis. The catalyst is stable and reusable until four catalytic cycles.