Application of Supported Liquid Membrane to separation and Concentration of Amino Acid

本工作旨在揭示支撑液膜分离浓缩氨基酸的机理，为实际的液膜过程设计提供指导。实验结果如下：1.以色氨酸、甲基三辛基氯化铵和正癸醇分别为氨基酸、载体和油相，研究了氨基酸的萃取平衡。在pH&gt;12时，氨基酸和氢氧根离子的平衡常数K_A<OH>分别为8和0.5.色氨酸的稳态渗透速率使用薄膜流动池测量，其中使用浸渍有三正辛基甲基氯化铵的1-癸醇溶液的聚丙烯的多孔平面膜。结果表明：（1）在油相中的扩散是反应的速率控制步骤; (2)pH=12时的质量通量大于pH=13时的质量通量。这一事实表明，存在最佳pH值的最大通量。(3)对于聚丙烯膜，载体在油相中的有效扩散系数D_E为0.96- 1.4 × 10 ~（-3）<-7>[cm ~ 2/s]，弯曲度<tau>为1.3 - 1.7。(4)利用扩散控制模型，可以从理论上解释实验结果.采用中空纤维管进行了色氨酸的非稳态渗透实验。实验结果可用油相中的扩散控制模型来解释，D_E为7 × 10 ~ 4 <-8>[cm ~ 2/s]，<tau>中空纤维管的D_E为2.6。

The aim of this work is to reveal the mechanism of separation and concentration of amino acid using supported liquid membranes and to give a guide to the design of the practical liquid membrane process. The experimental results are summarized as follow.1. The extraction equilibrium of amino acid was investigated experimentally using tryptophan, tri-n-octyl methyl ammonium chloride and 1-decanol as amino acid, carrier and oil phase respectively. In pH>12, the equilibrium constant K_A for amino acid and K_<OH> for hydroxide ion are 8 and 0.5 respectively.2. Steady state permeation rates of tryptophan were measured using a thin film flow cell where a porous plane film of polypropylene impregnated with 1-decanol solution of tri-n-octyl methyl ammonium chloride was used. As the results, (1) The rate determining step is the diffusion in the oil phase. (2) The mass flux at pH=12 is larger than that at pH=13. This fact shows that there is an optimum pH for the fighest flux. (3) The effective diffusivity D_E of the carrier in the oil phase is 0.96-1.4x10^<-7> [cm^2 /s] and the tortuosity <tau> is 1.3 - 1.7 for the polypropylene film. (4) By use of the diffusin control model, the experimental results can be explained theoretically.3. The experiments of unsteady permeation of tryptophan were carried out using hollow fiber tube. The results can be explained by the diffusion control model in the oil phase, and D_E is 7x10^<-8> [cm^2 /s] and <tau> is 2.6 for the hollow fiber tube.