Efficiency enhancement of photocatalytic degradation of tetracycline using reduced graphene oxide coordinated titania nanoplatelet

Abstract

Abstract The compound tetracycline hydrochloride (TCH) is an antibiotic used in the veterinary and medical application, however, it's over usage and accidental release into riverine and estuaries raising up serious threats to the ecology, environment and public health. This study focused on developing a low-cost catalyst to photodegrade TCH. Different formulations of TiO2 photocatalysts scaffolded with reduced graphene (denoted as TiO2-RGO-TiO2) were produced using a cost-effective sol-gel method. The mesoporous structured TiO2-RGO-TiO2 was tuned using citric acid as a complexing agent, Pluronic P-123 as a grafting agent and graphene oxide (GO) as structural “core” to guide the TiO2 growth. Our findings documented that the TiO2-RGO-TiO2 catalysts displayed high degradation efficiency towards TCH. This efficiency was determined to be improved by 22.8% under ultraviolet light and 32.80% under simulated solar energy within 2 h exposure respectively, relative to catalysis by TiO2 alone. It was found that 6 wt percent GO resulted in the highest degradation percentage (˜ 94%) due to the synergistic effects of inhibition of the electron-hole (e− and h+) recombination and improvement of effective reactive sites. The holes were found to the major factor in facilitating the photocatalytic degradation of TCH (75.4%), while the reactive oxygen species (ROS) accounted for the remaining 24.63%. Another factor to contribute to the superior performance of the TiO2-RGO-TiO2 compared to TiO2 alone lies in the decrease of the band gap energy of TiO2 from 3.20 to 2.87 eV upon introduction of reduced GO.