ACF电极上苋菜红的恒电流电化学脱色

Electrochemical Decolorization of Amaranth Solution on ACF Electrode under Galvanostatic Model

在恒电流模式下,研究了活性炭纤维(ACF)分别作阳极或阴极时对偶氮染料苋菜红的电氧化和电还原脱色。确定了ACF上苋菜红发生氧化和还原反应的电极电位分别是0.6V和?0.4V。ACF对苋菜红的脱色机制因电流密度的不同,明显地分为电氧化、电还原和吸附脱色三种过程。电氧化和电还原过程均遵循准一级反应动力学方程,并且电氧化的脱色速率常数与电流密度线性相关。电氧化脱色率在电流密度为0.5mA?cm?2时可以达到99.1%,TOC和COD去除率最大可分别达到32.8%和52.1%;电还原脱色率在电流密度为?1.0mA?cm?2时达到100%,TOC和COD去除率最大可分别达到58.0%和61.4%。

The electrooxidative and electroreductive decolorization processes of amaranth dye solution on ACF which acts as anode and cathode were respectively investigated. The potentials of oxidization and reduction for amaranth decolorization on ACF were ascertained at 0.6V and -0.4V, respectively. According to different current densities, the decolorization mechanism is specified into three processes as electrooxidation, electroreduction and adsorption. The pseudo-first order kinetics equations were both obtained in the process of electroreduction and electrooxidation. Furthermore, for the electrooxidative process, the rate constants relate to the current densities linearly. The color removal may be up to 99.1% when the current density is 0.5mA·cm^-2. The maximum TOC and COD removal is 32.8% and 52.1% respectively for the electrooxidation. On the other hand, for the electroreduction 100% color removal ratio may be obtained when the current density of -1.0mA·cm^-2 is applied, and the maximum TOC and COD removal is 58.0% and 61.4%, respectively.