Copper (II) Ion Exchange Properties of Alginate and Chitosan Free–Standing Membranes Composited with Zeolite

Abstract

Novel composite materials of zeolite and polysaccharides were developed for efficient removal of Cu²⁺ ion in aqueous phase. Zeolite–composited alginate free–standing membranes were successfully prepared by chemical cross–linking of dried sodium alginate containing zeolite. Although the combination of zeolite with alginate was found to be advantageous in terms of improved handling, reduced the amount of Cu²⁺ ion–exchange per unit mass. Therefore, zeolite combined alginate free–standing membranes with improved water permeability by the addition of plasticizers were prepared, and their ion exchange capacities were estimated. However, the improvement in water permeability did not result in an increase in ion exchange capacity. Chitosan free–standing membrane containing zeolite was also prepared by a similar method. The ion–exchange capacity of the zeolite composited chitosan free–standing membrane was also determined and found to be improved compared to the zeolite composited alginate membrane. These results suggest the use of membrane substrate with less polarity is effective in reducing ion–exchange inhibition.