Strongly coupled FeOOH nanoparticles/O doped g-C 3 N 4 nanosheets for visible-light-driven effective treatment of oxytetracycline hydrochlorides

This study rationally designed a novel heterogeneous photocatalyst through in situ precipitation of amorphous FeOOH nanoparticles on the porous oxygen doped g-C 3 N 4 nanosheets (FeOOH NPs/O-CNNS). The synergistic effect of FeOOH coupling and O doping promoted the photocatalysis degradation for the oxytetracycline hydrochloride (OTC) from 55.47% to 78.95% in 90 min, with TOC mineralization efficiency of 45%. Meanwhile, the optimal conditions in FeOOH NPs/O-CNNS/vis system predicted by the response surface method (RSM) were provided below: the catalyst dosage is 0.594 g/L, the electricity is 17.665 A, the initial pH is 5.82, and OTC degradation can reach 81.337%. FeOOH coupling could greatly reduce carriers’ recombination and broaden visible light absorption range, and O doping could form Fe-O bond for the strongly coupled interface and also optimize electronic structure to promote the dissociation of excitons. FeOOH NPs/O-CNNS catalyst had potentially practical application for high (10 mg/L) and low (1 μM) OTC pollution under natural light irradiation. Based on the liquid chromatograph mass spectrometer analysis (LC-MS), the possible degradation pathway of OTC was proposed, and meanwhile combined with quantitative structure activity relationship (QSAR) prediction, the harmless treatment of OTC pollution by FeOOH NPs/O-CNNS photocatalysis could be achieved.