Abstract During the process of Cr(III) recovery from an aqueous solution using an electrodialysis or a bipolar membrane electrodialysis (BMED) system, the purity and recovery are often low because of the migration of co-existing cation ions, such as Na+, K+, Ca2+, and Mg2+. In this study, a modified BMED system was used to recycle Cr(III) from an aqueous solution in the form of Na2CrO4, which is a basic compound in the chromate chemical industry, after Cr(III) was oxidized to Cr(VI) by H2O2 under alkaline conditions. The electrolyte concentration in the Cr(III) solution and the current density influenced the chromium recovery, current efficiency, and specific energy consumption. Under optimal experimental parameters, i.e., 5.0 g/L Na2SO4 in Cr(III) solution and a current density of 0.5 mA/cm2, more than Cr(III) of 87.8% could be recycled. When the number of recovery chamber modules increased from one to two and then three, the current efficiency increased from 23.2% to 45.6% and 67.6%, and the specific energy consumption decreased from 1.19 to 0.89 and 0.73 kW∙h/g of chromium. The present technology was therefore found effective for recovering Cr(III) from aqueous solutions.

中文翻译：

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使用改进的双极膜电渗析从水溶液中以 Na2CrO4 形式回收 Cr(III)

摘要 在使用电渗析或双极膜电渗析 (BMED) 系统从水溶液中回收 Cr(III) 的过程中，由于共存阳离子如 Na+、K+ 的迁移，纯度和回收率往往较低。 、Ca2+ 和 Mg2+。在这项研究中，改进的 BMED 系统用于在 Cr(III) 被氧化成 Cr(VI) 后以 Na2CrO4 的形式从水溶液中回收 Cr(III)，Na2CrO4 是铬酸盐化学工业中的一种碱性化合物。 H2O2 在碱性条件下。Cr(III) 溶液中的电解质浓度和电流密度影响铬的回收率、电流效率和比能量消耗。在最佳实验参数下，即在 Cr(III) 溶液中 5.0 g/L Na2SO4 和 0.5 mA/cm2 的电流密度下，可以回收 87.8% 以上的 Cr(III)。当回收室模块数量从1个增加到2个再到3个时，电流效率分别从23.2%提高到45.6%和67.6%，比能耗从1.19降低到0.89和0.73 kW·h/g铬。因此发现本技术对于从水溶液中回收Cr(III)是有效的。