アルミニウムのアノード酸化法により作成したイオン透過用メンブレンについて

抄録

Porous anodic oxide films on Al with a small diameter were formed in (a) 15% sulfuric acid at 20V and the films with a large one were obtained in (b) Kalcolor solution at 80V. Then the specimens were cathodically electrolyzed in the same solution and the films (membranes) were detached from Al metalic substrate by hydrogen gas evoluted at the bottom of the pores.
Scanning Electron Micrographic observation revealed no barrir layer for either of the films produced from (a) or (b). Pores in the films formed from (a) were linked together due to irregular dissolution, while for films formed in solution (b), the film structure was almost regular, with much less pore-linkage. The permeation behavior of ions in the prepared membranes was examined with Fe³⁺ -sulfosalicylate and Ni²⁺ -sulfate solutions by applying a constant voltage of 30V. To avoid hydration of the membranes in the humid atmosphere, it was neccessary to keep the membranes in a desicator before the experiment. With the membranes prepared, anions were easier to permeated more easily than cations because the alumina membranes in acidic solutions have positive zeta potential, with the result that only anions adsorb on the inner surfaces of the pores and migrate towards the anode during the electrodialysis.