低电压电解模拟高砷地下水中As(Ⅲ)的转化研究

Conversion Rate Study of As(Ⅲ)in Simulated High Arsenic Groundwater by Electrolysis at Low Voltage

建立阴阳极混合和阴阳极隔离的电解池研究模拟高砷地下水中As（Ⅲ）在低电压条件下的转化与去除规律。在混合电解池与分离体系阳极池中,在施加电压为0.1～0.8 V时,水体中的As（Ⅲ）均能转化As（Ⅴ）,并得到有效去除。As（Ⅲ）浓度变化动力学符合指数式衰减方程。在As（Ⅲ）转化速率与As（Ⅲ）浓度和电压之间建立数学模型：电压一定时,As（Ⅲ）的转化速率与其浓度成正比;浓度一定时,As（Ⅲ）的转化速率与电压成指数式增长关系。混合体系As（Ⅲ）的转化速率与砷去除速率均高于分离体系,原因是盐桥增大了分离体系的电阻。能耗分析表明,研究的电压范围内,电压越低,As（Ⅲ）转化与去除所消耗的能量越小,混合体系消耗的能量小于分离体系。

Mixed electrolytic cells and separated electrolytic cells have been established to research the conversion and removal of As （Ⅲ ） in simulated high arsenical content groundwater at low voltage. When the applied voltage is 0.1-0.8 V, As （Ⅲ ） can all be converted to As （ V ） and effectively removed in mixed electrolytic cells and anode cells of divided systems. The change kinetics of As （ Ⅲ ） concentration conforms to the exponential decay equation, and the mathematical models are established among the conversion rate of As （Ⅲ ）, the conversion rate of As （Ⅲ ） and the voltage. When voltage is constant, the conversion rate of As （ Ⅲ ） is proportional to its concentration; when the concentration of As （Ⅲ ） is constant, the conversion rate of As （Ⅲ ） has an exponential growth relation with voltage. The conversion rate and removal rate of As （Ⅲ ） in mixed electrolytic cells are higher than those in the anode cells of separated systems, for the reason of high resistance of the salt bridge in the separated systems. Energy consumption analysis shows that the consumed energy of the conversion and removal of As （ Ⅲ ） will reduce with the, decrease of voltage, and the consumed energy in mixed systems is less than that in the separation systems.