Solvothermal synthesis of MIL-53Fe@g-C3N4 for peroxymonosulfate activation towards enhanced photocatalytic performance

The MIL-53Fe@g-C3N4 samples were prepared by solvothermal method and recorded as CM-x. The potocatalytic activity of the MIL-53Fe@g-C3N4 was significantly higher than MIL-53Fe, and it might be due to the successfully constructed heterojunction promoting the migration and separation effciency of photo-generated electron and hole pairs. In order to further enhance the potocatalytic activity of the MIL-53Fe@g-C3N4, peroxymonosulfate was introduced into the MIL-53Fe@g-C3N4/Vis system, and the peroxymonosulfate could be simultaneously activated by photogenerated electron and iron to form sulfate radical under visible light irradiation. Therefore, the degradation efficiency of oxytetracycline hydrochloride was enhanced obviously. Meantime, the effects of peroxymonosulfate dosage, oxytetracycline hydrochloride concentration, temperature and pH on the degrada-tion efficiency of oxytetracycline hydrochloride were studied systematically. Meanwhile, the free radical catching experiments and electron spin resonance analysis confirmed that the main active substances were sulfate radical and hole. Finally, the mechanism and possible degradation pathways of MIL-53Fe@g-C3N4 acti-vating peroxymonosulfate to degrade oxytetracycline hydrochloride were proposed.