工艺参数对电去离子技术浓缩分离含镍离子溶液的影响

Influences of Operation Parameters on Concentration and Separation of Nickel-Containing Solution by Electrodeionization Process

采用浓缩室填充树脂的强化电去离子(EDI)对含Ni 2+溶液进行了浓缩分离,从中研究了工作电压、淡化室隔板厚度、原水浓度及组分对EDI分离性能的影响.结果表明,在15V电压下,EDI以增强传质模式运行可在较低能耗下获得高质量的出水;电压增大使淡水室内发生水解离而产生结垢,影响EDI的稳定运行.淡化室隔板由3mm增至5mm时,膜堆电阻增大,分离效率降低.对于含Ni 2+为50mg.L-1的NiSO4原水,在优化条件下,浓、淡水出水中Ni 2+浓度分别为11 031和2.78mg.L-1,Ni 2+的浓缩倍数达223.对于含Ni 2+和Cu2+各25mg.L-1的双组分原水,EDI对Cu2+有更好的浓缩效果.实验结束时,浓水出水中Ni 2+、Cu2+浓度分别为3 258和4 690mg.L-1,浓缩倍数分别为130和187;淡水出水中Ni 2+及Cu2+浓度分别为4.71和3.71mg.L-1.

The enhanced electrodeionization（EDI） in the dilute and concentrate chambers filled with ion exchanges resins was adopted for the concentration and separation of nickel-containing solution.The influences of operation voltage,partition thickness of the dilute chamber,feed concentration and composition on separation performance were examined.The results show that the EDI process operating under the enhanced mass transfer mode at applied stack voltage of 15V could ensure high quality effluent with lower energy consumption.As the voltage increased,significant water decomposition occurred in the dilute compartments,resulting in scaling problem and unstable operation.When the partition thickness of dilute chambers increased from 3mm to 5mm,the separation performance of the EDI process decreased as the stack resistance increased.Under the optimized conditions,for the Ni2＋ feed concentration of 50 mg·L-1,the Ni2＋ concentration of the outlet concentrate and dilute was 11 131 and 2.78 mg·L-1 respectively,i.e.,the concentration ratio of higher than 223.However,when the feed solution contained Ni2＋and Cu2＋ with the same concentration of 25 mg·L-1,the concentration effect of Cu2＋ was better than that of Ni2＋.At the end of the experiment,the concentration of Ni2＋and Cu2＋ in the concentrate effluent was 3 258 and 4 690mg·L-1 while that in the dilute effluent was 4.71 and 3.71 mg·L-1,respectively.