对添加Ce3+的甲基橙模拟废水进行了电催化处理实验,考察了Ce3+电催化降解甲基橙的反应动力学;为探讨Ce3+电催化降解甲基橙的脱色机理,将废水分别置入有隔膜和无隔膜电解槽中,在不同的条件(Ce3+的投加方式、位置和搅拌方式)下进行电解,测定分析了废水在电解过程中铈含量、甲基橙浓度、COD及体系紫外-可见吸收光谱图的变化。实验结果表明,Ce3+对甲基橙的电催化反应符合一级反应动力学;Ce3+对甲基橙脱色的电催化反应主要发生在阴极;加入废水中的Ce3+主要是通过将电解生成的H2O2还原为具有强氧化性的.OH进攻甲基橙分子中的偶氮键和Ce3+氧化生成的Ce4+与甲基橙的生色基团络合,使其吸收峰兰移而达到其电催化脱色的目的。
Experiment of electro-catalytic degradation for treatment of wastewater containing methyl orange was carried out with Ce3+ as catalyst.The kinetics of electro-catalytic degradation wastewater in the Ce3+system was investigated.In order to probe the decoloring mechanism of Ce3+ to the electro-catalytic degradation of methyl orange,a diaphragmless cell and a diaphragm cell were both filled with the wastewater respectively,and then electrolyzed in different conditions(concluding the dosing method,dosing position of Ce3+ and stirring mode).The changes of cerium concentration,methyl orange concentration,the chemical oxygen demand(COD),and UV-vis spectral in the electrolysis process were determined and analyzed.The results showed that the degradation of methyl orange in the Ce3+system accorded with first-order kinetics.The electro-catalytic degradation reaction of Ce3+ to the decolorization of methyl orange mainly happened in the cathode.The Ce3+ in wastewater mainly reduced H2O2 to ·OH,which had strong oxidizability,and could attack the azo bonds in the methyl orange and oxidize Ce3+ to Ce4+.Then the Ce4+,complexed with the chromophore of methyl orange,was resulting in the blue shift of its absorption peaks to achieve the decolourization.