(517b) Modifying Surface Properties of Cation Exchange Membranes Utilizing Chitosan for Electrodialysis

Desalination utilizing electrodialysis can be used to obtain freshwater from saltwater brines. Removal of salts using electrodialysis can be inefficient at low ionic concentrations leading to limited adoption in desalination processes. The hydrophilic properties of coated cation exchange membranes were studied to determine the impact on desalination. Chitosan with varying degrees of deacetylation (approximately 15%, 30% and 50%) were obtained using a heated NaOH solution. The resulting coated membranes possessed reduced contact angles 21%, 47%, and 62%, respectively, compared to the control. The success of coating was determined using FTIR and SEM. A base membrane as well as a series of coated membranes were tested to determine how electrodialysis parameter such as limiting current density (LCD), ionic flux, and current efficiency were affected by the level of membrane hydrophobicity. Low ionic concentration regimes (less than 1000 ppm NaCl solution) tend to be the most challenging for electrodialysis systems; therefore, special attention was paid to parameters in this regime. This study aims to show that modifying the membrane to be more hydrophilic improves electrodialysis performance at low ionic concentration regimes.