聚丙烯中空纤维膜/二(2-乙基已基)膦酸体系萃取水溶液中铜离子的研究

研究了聚丙烯中空纤维膜接触萃取器中二(2-乙基已基)磷酸萃取金属铜离子的工艺条件以及溶剂夹带,分析了原料的pH值、两相流速、有机相初始铜离子浓度以及萃取膜面积对萃取效率的影响,结果表明,两相流速、萃取膜面积对萃取率基本无影响,而水溶液的pH值和有机相初始铜离子浓度的改变使萃取率在40%～99%之间变化.这主要是由于整个萃取过程的传质阻力主要来源于D2EHPA和Cu2 的界面配位络合反应阻力,当铜浓度比较高时,传质阻力或传质系数与铜浓度无关,其值基本不变;而当铜浓度降低时,传质阻力随着铜浓度的降低而增大,传质系数则随着铜浓度的降低而减小.

Extracting copper ions from aqueous solution using D2EHPA in polypropylene hollow fibre membrane

In this paper, the membrane extraction of copper ions was carried out using hydrophobic polypropylene hollow fiber membrane modules and kerosene solutions containing Di-(2-ethylhexyl)phosphoric acid as extractant. The influences of operation conditions on the extraction efficiency were studied. Experimental results showed the extraction efficiency were independent of the flow velocities of two phases and the areas of membrane. However, the changes of pH of aqueous phase and initial Cu2+ concentration in the organic phase made the extraction efficiency vary from 40% ～ 99%. This was because that the overall mass transfer resistance was controlled by interfacial reactions rather than the aqueous and organic boundary layer. The mass transfer resistance was independent of Cu2+ at high copper ions concentration; however, when the copper concentration was low, the mass transfer resistance increased as Cu2+ concentration got smaller, and the mass transfer coefficient decreased as Cu2+ concentration got smaller.