Adsorption of cadmium and strontium on cellulose/alginic acid ion-exchange membrane

Cellulose/alginic acid (RC-AC) ion-exchange membrane was prepared by coagulating a blend of cellulose cuoxam and alginate solution. The RC-AC membrane was used satisfactory for the adsorption of Cd2+ and Sr2+ ions. The effects of ion concentrations, ionic strength, pH, adsorption time, desorption time and species of complexing agents on adsorbed amount (c(A)) of the RC-AC membrane were studied by a batch method, and the metal ions concentrations were measured with atomic absorption spectrophotometer (AAS). The c(A) values of Cd2+ and Sr2+ On the membrane were 0.79 meg g(-1) at pH 5.8, and 0.75 meg g(-1) at pH 6.0, respectively. After adding EDTA or oxalic acid, the c(A) values of Cd2+ and Sr2+ in the solution including Cu2+ and Fe3+ were much larger than those of Cu2+ and Fe3+, and the EDTA was more efficient in the enhancement of the c(A) values of Cd2+ and Sr2+ than oxalic acid. In this case (EDTA), the selectivity of the metal ions adsorbed into the membrane was in the order of Sr2+ > Cd2+ > Fe3+ > Cu2+. Th, preparation of RC-AC membrane is simple and less expensive. (C) 1999 Elsevier Science B.V. All rights reserved.