Photocatalytic degradation of tetracycline antibiotics using delafossite silver ferrite-based Z-scheme photocatalyst: Pathways and mechanism insight.

Tetracycline (TC), a widely used antibiotic, is easy to enter the aquatic ecosystem through soil erosion, livestock manure and wastewater discharge, resulting in a series of risks. The application of Z-scheme photocatalysts with efficient interface charge separation and transfer has been regard as an effective strategy for antibiotic degradation. Herein, a novel ternary Z-scheme BiOCl/Ag/AgFeO was successfully synthesized by ultrasound-assisted ethanol reduction of Ag on the interface of BiOCl and AgFeO. The BiOCl/Ag/AgFeO Z-scheme system exhibited an enhanced photocatalytic degradation capability for TC, which was over 6.5 times and 2.4 times higher than those of AgFeO and BiOCl/AgFeO system, respectively. The photocatalytic process of TC was explored, and the results indicated that an optimum catalyst concentration of 0.5 g L and a primeval pH (without adjustment) favored the degradation process, while the introduction of exogenous anions (CO, SO and NO) and organic matter (HA) supressed the degradation of TC. Simultaneously, the possible pathway for the degradation process of TC was presented based on the liquid chromatography-mass spectrometry (LC-MS) analysis. Active species trapping experiments and ESR spectra revealed the significant contribution of O in the TC degradation, and verified the Z-scheme mechanism of the BiOCl/Ag/AgFeO system.