Construction of Fe3S4/g-C3N4 composites as photo-Fenton-like catalysts to realize high-efficiency degradation of pollutants

To perfect the photocatalytic performance of Fe 3 S 4 under visible light irradiation using tetracycline hydrochloride (TCH) as a target contaminant, magnetic Fe 3 S 4 /g-C 3 N 4 composites with a visible light response were synthesized by a one-step hydrothermal method . The effects of varying quality ratios, temperatures, pH value, and H 2 O 2 concentrations on photocatalysis was investigated, and the composites were characterized by XRD , FTIR, XPS, SEM, etc. The results show that the highest photo-Fenton catalytic efficiency is obtained for a composite with a Fe 3 S 4 to g-C 3 N 4 quality ratio of is 1:0.75 (Fe 1 C 0.75 ). More than 97.5% of TCH is removed by Fe 3 S 4 /g-C 3 N 4 /H 2 O 2 within 60 min under visible light irradiation and near-neutral conditions (pH 6.2), and its first-order kinetic constant is determined to be 0.06802 min −1 . The removal efficiency for Fe 3 S 4 /g-C 3 N 4 is 1.61 and 13.34 times higher than that of the parent Fe 3 S 4 and g-C 3 N 4 , respectively. At this time, g-C 3 N 4 can effectively increase the leaching of S 0 . The effects of different active species in the TCH degradation experiment with the Fe 1 C 0.75 composite were studied, and it is found that h + , · O 2 − , and ·OH radicals are the main substances involved in the degradation of TCH. The synthesized Fe 3 S 4 /g-C 3 N 4 catalyst is a promising heterogeneous photo-Fenton catalyst for the removal of organic pollutants.