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 Bi12O17Cl2/Ag/AgFeO2 was successfully synthesized by ultrasound-assisted ethanol reduction of Ag+ on the interface of Bi12O17Cl2 and AgFeO2. The Bi12O17Cl2/Ag/AgFeO2 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 AgFeO2 and Bi12O17Cl2/AgFeO2 system, respectively. The photocatalytic process of TC was explored, and the results indicated that an optimum catalyst concentration of 0.5 g L-1 and a primeval pH (without adjustment) favored the degradation process, while the introduction of exogenous anions (CO32-, SO42- and NO3-) 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-center dot(2)- in the TC degradation, and verified the Z-scheme mechanism of the Bi12O17Cl2/Ag/AgFeO2 system. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Tetracycline, a widely used antibiotic, poses risks to the aquatic ecosystem. A novel ternary Z-scheme Bi12O17Cl2/Ag/AgFeO2 exhibited enhanced photocatalytic degradation of tetracycline. Optimal catalyst concentration and pH conditions favored the degradation process, while exogenous anions and organic matter hindered it. O-center dot(2)- played a significant role in tetracycline degradation within the Bi12O17Cl2/Ag/AgFeO2 system.