Preparation of non-polluting Tb-doped mesoporous carbon nitride photocatalyst and study on the efficacy and mechanism of degradation of antibiotics in water

Given that the biological treatment of antibiotic wastewater can easily induce resistant bacteria, the photocatalytic degradation of antibiotics is considered as a better method for treating antibiotic wastewater. Therefore, the ability to remove Tylosin (TYL) and Tetracycline (TC) in aqueous solution using rare earth element Tb-doped g-C3N4 under simulated natural solar radiation was investigated. A series of rare earth Tb3+ doped mesoporous g-C3N4 were successfully prepared by nitric acid treatment and Tb(NO3)3·5H2O samples showed significantly higher degradation efficiency for TYL and TC than pure g-C3N4. Leaching toxicity experiments were carried out on the catalyst using chard seeds and demonstrated negligible toxicity of the leachate from the catalyst. The structure, elemental state, optical properties, morphology, and photogenerated carrier separation of the prepared xTCN catalysts were characterized by XRD, XPS, UV-Vis DRS, TEM, and PL. The results show that Tb doping enhanced the photocatalytic activity of the g-C3N4 catalyst by narrowing the band gap while improving the light-trapping ability; The separation and transport rate of photogenerated carriers were significantly increased after Tb doping. Finally, a simple, efficient, and non-polluting Tb-doped carbon nitride photocatalyst is successfully developed in this paper.