Efficient degradation of tetracycline hydrochloride by activated peroxymonosulfate with PdO/CuFe2O4/coal-bearing strata kaolinite composite

Abstract

In this study, a 4%PdO/CuFe2O4/coal-bearing strata kaolinite (4%PdO/CFO/CK) composite was successfully prepared using a simple hydrothermal method and used as a catalyst for tetracycline hydrochloride (TCH) degradation in wastewater by activating peroxymonosulfate (PMS) in visible light. The synthesized catalyst was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis. The effects of different catalyst and PMS dosages, pH of the initial solution, and other key parameters on TCH removal were studied. The results showed that the TCH removal rate using the 4%PdO/CFO/CK + PMS + Vis system was as high as 91.96 % within 20 min at a pH of 4.0, catalyst dosage of 20 mg, and PMS dosage of 1.5 mL. In addition, the TCH removal rate remained >85 % after three cycles, thereby verifying the stability and reusability of the 4%PdO/CFO/CK composite. Finally, free radical capture experiments and electron paramagnetic resonance identified the reactive oxygen species involved in the degradation process as 1O2, •O2−, h+, •OH, and SO4•−, and we proposed a mechanism for TCH removal using the 4%PdO/CFO/CK + PMS + Vis system. Our findings provide a promising solution for removing TCH from wastewater using the 4%PdO/CFO/CK + PMS + Vis system.