LCQDs modified Bi2MoO6 hydrangea composite photocatalyst for tetracycline degradation from wastewater: Performance, efficiency, and adsorption synergistic photocatalytic mechanism

This study used alkaline lignin as the carbon source for preparing alkaline lignin carbon quantum dots (LCQDs) based on the solvothermal method . To achieve efficient photocatalytic degradation of tetracyclic hydrochloride antibiotics (TCH), hydrangea-shaped LCQDs/Bi 2 MoO 6 composites were prepared in situ by the solvothermal method exploiting the optical properties of LCQDs. The composite material was systematically characterized using XRD , FTIR , XPS , SEM, TEM , EIS , nitrogen adsorption-desorption testing, and UV–vis DRS to determine its crystal structure, microstructure, and optoelectronic properties. The results show that the sample has high purity and good crystallinity . The experiment on photocatalytic degradation further demonstrated that the LCQDs/Bi 2 MoO 6 composite material modified with LCQDs exhibited superior photocatalytic activity compared to a single Bi 2 MoO 6 . Among them, BMO/LCQDs-7 showed the best effect. After 120 min of illumination, the rate of TCH removal through photocatalysis was 98.76%, with a degradation rate constant: K = 0.026 min −1 . After five cycles, the removal rate of TCH can still be maintained at 79.35%. The photocatalytic degradation of TCH has been demonstrated through EPR and LC-MS experiments primarily caused by h + and ·O 2 - .