Mn促进Fe/C微电解反应速率及降解污染物机理

为了扩宽铁炭微电解工艺的适用范围及提高处理效率，以铸铁屑、椰壳活性炭为原料，添加Mn构建Fe/Mn/C三元微电解体系处理甲基橙(MO)模拟染料废水。利用SEM-EDS、FTIR及Raman光谱分析了Fe、Mn和活性炭表面形貌及元素组成，采用UV和三维荧光光谱(EEM)探究了有机物成分的变化，对比了Fe/Mn/C和Fe/C微电解体系对MO的降解效果，揭示了Fe/Mn/C三元微电解体系降解MO的反应机理和反应动力学。结果表明，反应后的Fe、Mn和炭填料表面存在铁氧化物、铁氢氧化物及锰氧化物，Fe/Mn/C三元微电解体系可断裂MO的氮氮双键，破坏苯环结构。MO的降解过程符合准一级反应动力学模型；Fe/Mn/C微电解体系对MO降解的反应速率常数由Fe/C微电解体系的5.7381×10^–4 min^–1提高至9.3834×10^–4 min^–1，降解速率和降解效果显著优于Fe/C微电解体系。

Mechanisms on Zerovalent Mn promotes Fe/C microelectrolysis reaction rate and degrades pollutants

Fe/C microelectrolysis process has low wastewater treatment efficiency and is prone to hardening problems, and is only suitable for treating acidic wastewater. In order to broaden the application range of Fe/C microelectrolysis process and improve the treatment efficiency, Fe/Mn/C ternary microelectrolysis system was constructed by adding zerovalent Mn and methyl orange (MO) simulated dye wastewater was treated. The morphology changes of iron, manganese and carbon and the compositions of surface elements were analyzed using SEM-EDS, Fourier transform infrared spectroscopy and Raman spectra. The changes of organic compounds in the wastewater were explored using UV-Vis spectra and three-dimensional fluorescence spectra before and after the reaction. Degradation performance of methyl orange was compared between Fe/Mn/C microelectrolysis and Fe/C microelectrolysis. Reaction mechanisms and reaction kinetics of methyl orange degradation were revealed using Fe/Mn/C ternary microelectrolysis system. The results showed that iron oxides, hydroxides and manganese oxides were existed on the surface of iron, manganese and carbon after the reaction. Fe/Mn/C ternary microelectrolysis broke nitrogen-nitrogen double bond of methyl orange and destroyed the structure of benzene ring. The degradation process of methyl orange conformed to second-order kinetics. After zero-valent Mn was added into Fe/C binary microelectrolysis system, the reaction efficiency constant of methyl orange degradation increased from 5.7381×10_^-4min_^?1 to 9.38336×10_^-4min_^?1. The degradation rate and degradation effect of methyl orange in the Fe/Mn/C microelectrolysis system was significantly better than those in the Fe/C microelectrolysis system.