Cu^2＋在支撑液膜中的传质过程

Transport of Copper(II) Ion in Supported Liquid Membrane

研究了以疏水性多孔聚丙烯膜(Celgard2500)为支撑体和LIX984的煤油溶液为膜液的支撑液膜体系萃取Cu2+的传质过程.采用双膜理论描述Cu2+通过平板支撑液膜的传质过程,建立了其在稳态下的传质动力学方程,且当反萃取侧酸浓度大于2mol/L时,反萃取侧的传质阻力可以忽略;利用膜内分传质系数km表征支撑液膜膜液的流失行为,在传质过程中,km先增大而后逐渐减小,且载体的流失速率大于稀释剂煤油的流失速率.考察了操作条件对传质和膜液流失速率的影响,结果表明,Cu2+初始传质通量随载体初始浓度、料液初始pH值和料液初始Cu2+浓度的增大而增大;载体初始浓度越大,膜液流失越快;料液初始Cu2+浓度增大,膜液流失越慢;料液相pH值的改变对膜液流失速率没有影响.

Transport of Cu^2＋ through supported liquid membrane （SLM） using Celgard 2500 as support and LIX984 dissolved in kerosene as cartier was studied. Based on double membrane theory, a transport rate model was used to describe the transport process under steady state. When the acid concentration in stripping solution was over 2 mol/L, the mass transfer resistance of stripping side could be neglected. The variation of separated mass transfer coefficient, km, in the membrane could be used to describe the degradation of SLM. During the process of mass transfer, km increased at the beginning and then decreased gradually. Moreover, the carrier was more inclined to lose than the kerosene diluent. The influences of operation conditions on the mass transfer and membrane liquid loss were also investigated. The results showed that the initial mass transfer flux J0 increased with the increase of initial concentrations of carrier and Cu^2＋, and initial pH value in feed solution. The loss of membrane liquid increased with the increase of carrier concentration in membrane liquid and the decrease of copper concentration in feed solution. However, the pH value had little influence on the loss of membrane liquid.