Promoted photocatalytic degradation of tetracycline hydrochloride by montmorillonite catalyst loaded with Cu/Mn

Semiconductor photocatalysis is a green and environmentally friendly antibiotic wastewater treatment technology without secondary pollution. In this paper, a series of montmorillonite (MMT) samples loaded with Cu, Mn, and Ni were prepared by impregnation method. The structure and spectral response of the as-prepared samples were characterized by powder X-ray diffraction, energy-dispersive spectroscopy, laser Raman spectroscopy, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), electrochemical impedance spectroscopy, and photocurrent response test. The photocatalytic degradation of tetracycline hydrochloride (TCH) was carried out under simulated solar irradiation, and the photocatalytic properties of MMT samples with different loads were investigated. The characterization results show that Cu and Mn have strong interaction with MMT, and composite photocatalyst Cu10Mn10-MMT has the smallest Nyquist arc and higher photocurrent intensity. Degradation experiments on TCH showed that Cu10Mn10-MMT had the best photocatalytic degradation, with a degradation rate of 79.78%, three times that of the original MMT. Active substances capture experiments showed that h(+) and O-2(.-) were the main active substances for the degradation of TCH by Cu10Mn10-MMT. After the combination of Cu, Mn, and MMT, the band structure changed, resulting in more h(+) and O-2(.-) involved in the redox reaction, thereby improving the photocatalytic degradation performance of TCH. In this work, a promising photocatalyst is used to efficiently and greenly degrade antibiotic wastewater.