Water desalination by neutralization dialysis with ion-exchange membranes: Flow rate and acid/alkali concentration effects

作者：Cherif M; Mkacher I; Dammak L^*; Ben Salah A; Walha K; Grande D; Nikonenko V

来源：Desalination, 2015, 361: 13-24.

DOI：10.1016/j.desal.2015.01.024

• Ion-exchange membrane
• Neutralization dialysis
• Desalination
• Three-compartment stack
• Kinetics modeling

Kinetics of surface water desalination by neutralization dialysis (ND) was studied in a three-compartment stack with ion-exchange membranes, and the process feasibility was evaluated. The pH and the ionic conductivity of a model saline solution (0.02 M NaCl) were measured during different ND operations in batch mode. The influence of the flow rate, the solution concentration in the alkali and acid compartments was investigated. It was found that, at the beginning of the operation, the ion-exchange kinetics was mainly controlled by the membrane diffusion. The maximal fluxes of exchanging ions (J(max)) (Na+ and H+ across CMX membrane, and Cl- and OH- across AMX membrane) were theoretically evaluated. The calculated and the experimentally measured fluxes at the beginning of batch operation were close. However, after some minutes of solution desalination, the salt concentration decreased, which involved diffusion boundary layer controlled kinetics. Hence, with time, the fluxes decreased and were considerably smaller than J(max). The increase/decrease in the add and alkali solution concentration resulted in corresponding increase/decrease in the ion-exchange rate. Recommendations have been provided to reduce the desalination duration.

• 出版日期2015-4-1