The transport of cobalt and zinc through a carboxylic ion-exchange membrane was investigated by using a system containing HCl as a receiver solution and cobalt chloride or zinc chloride as a feed solution. The transfer rate was found to be greatly affected by the H+ concentration in the receiver solution and metal concentration in the feed solution. The rate of transfer for zinc was about 25% higher than that of cobalt under the same experimental conditions (0.5M HCl as a receiver solution, 0.1M feed solution, and 5 h dialysis time).