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

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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.