Inverse micelle fabrication of ordered mesoporous manganese oxide and degradation of tetracycline hydrochloride

Ordered mesoporous manganese oxides (MnOx) were synthesized using the modified inverse micelle method. The crystal structure and surface morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The element content and changes in surface valence of catalysts were analyzed by X-ray photoelectron spectroscopy (XPS). The MnOx were used to activate peroxymonosulfate (PMS) to degrade tetracycline hydrochloride (TCH). The catalytic activity of MnOx was enhanced at a calcination temperature of 350 °C (MM-3). The degradation efficiency of TCH in MM-3/PMS system was 87.89% in 180 min. Appropriate dosages of catalyst and PMS improve the degradation efficiency of TCH. This system showed a wide range of pH application (3–9). In the presence of coexisting ions and humic acid, the degradation efficiency of TCH was still above 80%. The results of free radical capture experiment and electron paramagnetic resonance (EPR) test proved that the system activates PMS to produce three types of free radicals: SO4[rad]−, [rad]OH and 1O2. Therefore, MM-3 is a promising catalyst for the degradation of TCH in practical wastewater treatment.