Effect of porous spacers made by 3D printer on the electrodialysis desalination

摘要

Limiting current density (LCD) is known as an important parameter describing the efficiency of electrodialysis desalination. In this study, insertion of porous spacers within concentrate and diluate channels has been proposed in order to achieve a high LCD. A series of experiments for both cases with and without porous spacers were carried out. The results show that the insertion of porous spacers is quite effective in increasing the LCD, since the mechanical dispersion takes place in a porous medium, which effectively delays the depletion of ions on the membranes. Thus, the concentration polarization is suppressed. The increase in both pressure drop and electric power consumption can be minimized by further optimizing the geometrical structure of porous media.