对甲基苯酚电催化氧化机理

在无隔膜电解槽中, 利用线性伏安法和恒电流电解法研究了Ti/PbO2电极对于对甲基苯酚氧化的电催化活性, 通过阳极过程中对甲基苯酚及其氧化中间产物的液相色谱测定, 研究了对甲基苯酚电催化氧化降解的机理. 研究结果表明, Ti/PbO2电极能够有效地电催化氧化水溶液中的对甲基苯酚, 在25 ℃下, 初始浓度为2 mmol/L的对甲基苯酚溶液, 恒定电流密度为50 mA/cm2, 电解3 h, 对甲基苯酚的转化率为74.32%, 有机碳去除率为61.81%. 对甲基苯酚电氧化降解要经过生成对羟基苯甲醇、对羟基苯甲醛、对羟基苯甲酸、对苯二酚、对苯醌、顺丁烯二酸和草酸, 最终变成CO2的历程, 其中对苯二酚的氧化和顺丁烯二酸的氧化为反应的速控步骤.

Studies on Electrocatalytic Oxidation Mechanism of p-Methylphenol

Electrocatalytic activity of Ti/PbO2 anode on oxidation degradation of p-methylphenol was studied by linear sweeping voltammetry and galvanostatic electrolysis in an electrolytic cell without diaphragm. Electrocatalytic oxidation mechanism of p-methylphenol was explored by HPLC analysis of p-methylphenol and its degradation intermediates in anodic oxidation processes. The results indicat that Ti/PbO2 electrode can electrocatalyze the oxidation of p-methylphenol and its intermediates in the solution effectively. The conversion of p-methylphenol and the removal ratio of oganic carbon reached 74.31% and 61.8% in 3.0 h, respectively, in the electrolyzing process with constant current 50 mA/cm2 in the solution containig initial concentration 2 mmol/L of p-methylphenol at 25 ℃. The pathway of electrooxidation degradation of p-methylphenol may be p-methylphenol→p-hydroxybenmethanol→p-hydroxybenzaldehyde→p-hydroxybenzoic acid→hydroquinone→benzoquinone→maleic acid→oxalic acid, and the final product is CO2. The electrooxidation reactions of hydroquinone and maleic acid are the rate determining steps.