Preparation and properties of cation-exchange membranes based on commercial chlorosulfonated polyethylene (CSM) for diffusion dialysis

Cation-exchange membranes for diffusion dialysis (DD) were prepared by selecting chlorosulfonated polyethylene (CSM) and methacrylic acid (MAA) as framework and functional monomer, respectively. An interpenetrating network structure (IPN) was formed by free radical polymerization and consequent crosslinking reaction. The membranes possessed ion exchange capacities (IECs) of 1.98–3.12 mmol/g, water uptake (WR) of 12.7–34.8%, swelling degree of 72.7–170% as well as favorable thermal stability and alkali resistance (almost zero mass loss in hot alkali solution). The membranes were applied for DD process to recover alkali from NaOH/Na2WO4 system at 25 °C and 65 °C. Results indicated that coefficients for OH− (UOH) were in the range of 0.0015–0.018 m/h and separation factors (S) were in the range of 9–33 at 25 and 65 °C, respectively.