Novel porous perovskite composite CeO2@LaMnO3/3DOM SiO2 as an effective catalyst for activation of PMS toward oxidation of urotropine

Perovskites with stable crystal structure and excellent catalytic performance have attracted extensive attention in peroxomonosulfate (PMS) activation, however, severe agglomeration has always been the main obstacle limiting the catalytic activity of them, so novel perovskite catalysts are urgently needed. In this study, three-dimensional ordered macroporous silica (3DOM SiO2) was prepared by colloidal crystal template method, then CeO2@LaMnO3/3DOM SiO2 was prepared by sol-gel method combined with impregnation method and used to activate PMS for urotropine (URO) degradation. CeO2@LaMnO3/3DOM SiO2 activated PMS system exhibited high URO removal efficiency and quick kinetic, as 99.98 % URO was degraded even within 30 min. The catalyst has a wide pH range and still has high catalytic activity in the presence of organic matter and inorganic ions. The three components in CeO2@LaMnO3/3DOM SiO2 showed a synergetic effect. CeO2 and LaMnO3 were uniformly loaded on 3DOM SiO2, which effectively avoided agglomeration. The specific surface area of CeO2@LaMnO3/3DOM SiO2 was 11.88 times that of LaMnO3 prepared by sol-gel method. There are two redox cycles of Ce3+/Ce4+ and Mn2+/Mn3+/Mn4+ in CeO2 and LaMnO3, respectively, which synergistically realize the activation of PMS. Both quenching experiments and electron paramagnetic resonance (EPR) analysis revealed that that SO4−, OH and 1O2 jointly achieved the degradation of URO. In summary, CeO2@LaMnO3/3DOM SiO2 would be a promising candidate for practical wastewater treatment.