Study On The Performance And Mechanism Of CeO₂@LaMnO₃/3DOM SiO₂ Activated PMS To Degrade Urotropine

In this study,three-dimensional ordered macroporous perovskite composite was prepared,and a novel reaction mode of adsorption-assisted catalysis was tried to improve the problems of low oxidants utilization rate and poor treatment effect on low concentration pollutants in traditional advanced oxidation process.Using urotropine as a model pollutant,a peroxomonosulfate catalytic oxidation system was constructed to investigate the catalytic performance of the material,and the catalytic reaction mechanism was studied.The results are as follows:1)La Mn O₃/3DOM SiO₂ with different loadings were prepared by colloidal crystal template method combined with impregnation method.The highest catalytic activity was obtained when the concentration of dipping solution was 0.4 mol·L^-1,and the corresponding30 min urotropine removal rate and reaction rate reached 97.2%and 0.1976 min^-1,respectively.Urotropine molecules first decomposed to formaldehyde and ammonium nitrogen,then formaldehyde was oxidized to formic acid,and finally oxidized to carbon dioxide and water,some ammonium nitrogen was oxidized to nitrate nitrogen.2)CeO₂@La Mn O₃/3DOM SiO₂ with different loadings was prepared by impregnation method。The highest catalytic activity was obtained when the concentration of dipping solution was 0.2 mol·L^-1,the complete degradation was achieved within 20 min,and the reaction rate was 0.2919 min^-1.CeO₂@La Mn O₃/3DOM SiO₂ improved the contact efficiency and inhibited the quenching of reactive oxygen species in a novel adsorption-assisted catalytic reaction mode,and finally achieved high peroxymonosulfate utilization and efficient degradation of low-concentration pollutants.The synergistic electron cycle reaction between Ce³⁺/Ce⁴⁺and Mn²⁺/Mn³⁺/Mn⁴⁺triggered the decomposition of peroxymonosulfate molecules to produce a large number of strong oxidizing sulfate radicals,hydroxyl radicals and singlet oxygen,which further degraded urotropine molecules to produce formaldehyde and ammonium nitrogen,and then formaldehyde was oxidized to formic acid and finally oxidized to carbon dioxide and water,some ammonium nitrogen was oxidized to nitrate nitrogen.3)The catalytic degradation performance of CeO₂@La Mn O₃/3DOM SiO₂ on the actual wastewater of urotropine was investigated.The novel catalyst can achieve efficient catalytic degradation of urotropine in actual wastewater in a wide p H range（3-13）,and the peroxomonosulfate utilization rate was at a high level.In 5 cycles,the catalytic degradation rate of CeO₂@La Mn O₃/3DOM SiO₂ to urotropine remained above 99%.The catalytic degradation path of urotropine in actual wastewater is consistent with that of simulated wastewater.