A new cation-exchange polysaccharide membrane containing a diamine complexing agent for CO2 facilitated transport was developed. The facilitated transport of CO2 through a ethylenediamine (EDA) fixed-cation exchange polysaccharide has been studied. In this study, polysaccharide from marine alga. SA was used as polymer matrix in order to prepare a new fixed-carrier membrane for CO2 facilitated transport. The carrier was introduced in the membrane by soaking acidic cation-exchange membranes in EDA solutions. The EDA carrier exhibited a large facilitation effect in a cation-exchange polysaccharide membrane. The facilitation effect of CO2 through the water-swollen SA membrane was small compared with the EDA-fixed SA. The effect of the carrier (EDA) content oil the CO2 facilitated transport of the EDA-fixed membranes prepared by varying EDA content in membranes was investigated. It was found that the CO2 permeability of the EDA-fixed SA membranes increased with increasing carrier (EDA) content in the membrane. (C) 2004 Elsevier B.V. All rights reserved.