Degradation of Tetracycline (TC) by ZrO2-3DG/PMS System: Revealing the Role of Defects in the Conditions of Light Irradiation and Sulfate Accumulation

The application of advance oxidation processes (AOPs) based on the activation of peroxymonosulfate (PMS) is a great concern for wastewater treatment. Herein, ZrO2-3DG was constructed using a hydrothermal method for the degradation of tetracycline (TC) with PMS. The defective ZrO2-3DG materials were also prepared with plasma treatment. SEM and XPS results show that the ZrO2-3DG composite and the corresponding defective materials were successfully fabricated. The ZrO2 particles are distributed uniformly on the substrate material. Plasma can induce defects on the composite materials and create highly active sites. TC degradation results show that the ZrO2-3DG/PMS system can achieve a degradation efficiency of 92.9% for TC. The influences of defects on materials, light irradiation and sulfate accumulation were investigated. It has been found that defects can induce an inhibiting effect on the degradation process, which can be tuned by plasma time. The defective ZrO2-3DG/PMS system exhibits excellent resistance to the accumulation of sulfate, even showing enhanced degradation performances in specific conditions. The light irradiation has led to a higher degradation efficiency with the accumulation of sulfate compared with a dark environment. These findings give great guidance to the application of the ZrO2-3DG/PMS system for environmental protection.