电容去离子过程电吸附行为与法拉第反应关系及去除水体硬度

Relationship between Faradaic Reactions and Electro-Adsorption and Water Hardness Removal in Capacitive Deionization Process

采用活性炭涂层电极,研究了电容去离子过程中电吸附行为与法拉第反应之间的关系,同时以CaCl_2和MgCl_2溶液模拟硬度水体,探讨了电容去离子技术对硬度去除的可持续性。结果表明,随着电压的升高,电容去离子过程中有不同的法拉第反应发生,同时阴离子的电吸附行为促进了溶解氧和H_2O_2的还原;阳离子的电吸附行为促进了活性炭电极的氧化和水的电解,Cl^-的氧化不是出水pH变化的主要原因。电容去离子装置在去除钙镁离子时表现了很好的可持续性,钙镁离子不会对活性炭电极造成结垢问题。

The relationship between faradic reactions and electro-adsorption in capacitive deionization process was researched by using activated carbon electrodes. Meanwhile, using CaCl2 and MgCl2 solution to simulate hardness water, and the sustainability of hardness removal by capacitive deionization was studied. The results showed that, different faradic reactions could appear with the increase of applied voltage, the adsorption of anions promoted the reduction of DO and H2O2 while adsorption of cations contributed to the oxidation of activated carbon electrode and water electrolysis. The oxidation of CI was not the main reason for the fluctuations ofpH. The capacitive deionization showed a great sustainability of hardness removal, indicating that the Ca2＋ and Mga＋ could not lead to the scaling of activated carbon electrodes.