Construction of marigold-like ZnIn2S4@Tb-g-C3N4 heterojunction for facilitating photocatalytic degradation of tetracycline and tylosin under simulated solar irradiation

Due to the high biological toxicity and the propensity to induce antibiotic resistance, the treatment of antibiotic wastewater has consistently posed a formidable challenge. The semiconductor photocatalysts can efficiently and completely remove antibiotics from the wastewater to repair the water environment. Therefore, a novel ZnIn2S4/Tb-g-C3N4 (ZIS/TCN) photocatalyst was successfully synthesized in this paper and its ability to efficiently degrade antibiotics has been verified. The optimized 150ZIS/TCN photocatalyst showed excellent photocatalytic performance and stablility toward the degradation of tetracycline (TC) and tylosin (TYL) under sunlight simulated with a xenon lamp. Compared with pristine g-C3N4 and ZnIn2S4, the 150ZIS/TCN exhibited superior degradation performance for TC (TYL), about 3.2 (2.1) and 1.8 (1.5) times higher than them. Based on density functional theory (DFT) calculations and experimental characterization test results, it was confirmed that the Tb doping effectively regulates the intrinsic electric field and visible light absorption capacity. This study unveils the degradation mechanism of ZIS/TCN photocatalysis and provides an effective pathway for enhancing photocatalytic degradation through rare earth doping.