Abstract
An attempt was made to describe the filtration properties of the composite membrane of an Alaska Pollack roe membrane and an alginic acid salt. The composite membrane was prepared by casting 3 wt% sodium alginate aq. solution containing the roe membrane and then coagulating in the aq.solution of CaCl2 or BaCl2. The molecular orientation in the roe membrane was evaluated through the interference colour observed by a polarization microscope. The membrane permeability P was evaluated through the dead end filtration under the constant transmembrane pressure. The results are : (1) The molecular orientation maintained as prepared even after the filtration. (2) The value of P decreased in general with the filtration time for the salt solution except for the solutions employed in the preparation of the membrane. (3) The decrease proceeded through three steps ; the initial rapid decrease due to the decrease in the mean pore size, the second step of nearly constant filtration rate and the third step of slow decrease due to the dissolution of barium and/or alginate. (4) The P value at the second step showed minimum at 4 wt% in the case of NaCl aq. solution. (5) The permeability ratio between water and 4 wt% NaCl aq. solution changed with the organic solvent treatment. The value of P for the salt solution with various cations and a common anion under the constant mole concentration of 0.5 mol/ l showed the following relation ; Ca2+>K+≥Ba2+=Na+>NH4+>H+.
