双极膜电渗析法去除水溶液中Cr(Ⅵ)

运用双极膜电渗析法（BMED）去除模拟废水中的Cr（Ⅵ）并以H₂CrO₄的形式对其进行回收。探究了电解质浓度、电流密度、Cr（Ⅵ）初始浓度对Cr（Ⅵ）去除的影响。结果表明:当Cr（Ⅵ）初始浓度为500 mg/L时，电解质浓度为1 g/L，电流密度为2 mA/cm2时，Cr（Ⅵ）去除率最高为97.6%。当在BMED中串联2个和3个废水室时，可有效降低单位去除能耗，提高电流效率，且所有废水室中Cr（Ⅵ）去除率均>97.0%。随着废水室的数量从1增加到2和3，单位去除能耗分别从19.49×10-3 kW·h/g降低到7.76×10-3，4.17×10-3 kW·h/g，电流效率分别从31.5%提高到125.8%和284.4%。双极膜电渗析法可作为一种从水溶液中去除和回收Cr（Ⅵ）的有效方法。

REMOVAL OF HEXAVALENT CHROMIUM FROM AQUEOUS SOLUTION USING BIPOLAR MEMBRANE ELECTRODIALYSIS TECHNIQUE

In the present work, a bipolar membrane electrodialysis(BMED) was used to remove and recover hexavalent chromiumCr(Ⅵ)] in form of H₂CrO₄ from the simulated wastewater. The effects of electrolyte concentration in wastewater, current density, and initial Cr(Ⅵ) concentration on removal of Cr(Ⅵ) were investigated. The experimental results showed that the electrolyte concentration of 1 g/L and current density of 2 mA/cm2 were the optimal experimental conditions when initial Cr(Ⅵ) concentration was 500 mg/L, and the removal rate was 97.6%. A higher current efficiency (CE) and a lower specific energy consumption (SEC) were obtained when two and three wastewater compartment were equipped in the BMED system and Cr(Ⅵ) removal rates in all wastewater compartments were higher than 97.0%. With the increase in the number of equipped wastewater compartment from one to two and three in the BMED system, CE increased from 31.5% to 125.8% and 284.4%, SEC decreased from 19.49×10-3 to 7.76×10-3, 4.17×10-3 kW·h/g Cr(Ⅵ), respectively. Experimental results showed that the BMED was an effective method for the removal and recovery of Cr(Ⅵ) from aqueous solution.