イオン交換膜におけるカルシウムイオンの透過性

概要

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Permeability of calcium ions across heterogeneous ion exchange membranes prepared from pulverized ion exchange resins was examined together with sodium ions by the use of a seven compartment cell. Each compartment, alternately separated by cation and anion exchange membrane, was previously filled with the raw solution (mixed solution of NaCl and CaCl2), and electrodialyses were carried out for three hours. Both ions of the sample solution of the concentrated center compartment were determined. Permselectivity of calcium ions against sodium ions is usually larger than unity under the conditions that sulfonic and carboxylic type cation exchange resins are used as raw materials for the membranes. Permselectivity of calcium ions shows decrease with the increase of current densities and total concentrations of raw solutions. Permeabilities of calcium and sodium ions across sulfonic acid resin membranes are larger than those across carboxylic acid ones. At pH of the neutral medium, the permeabilities of both ions are maximum. Permselectivity of calcium ions against sodium ions across carboxylic acid resin membranes is smaller than that across sulfonic acid ones, and these results show that there are some binding forces besides the Coulomb forces between calcium ions and carboxylic acid radical.
日本海水学会の論文