Evaluating the effects of temperature on flow-by capacitive deionization

Abstract

Capacitive Deionization (CDI) is an emerging technology in the desalination industry. It is critical to assess the parameters influencing desalination in capacitive deionization cells for understanding the deionization procedure and optimizing the desalination rate. Temperature is one of the critical parameters affecting desalination in this method. In the present study, Flow-by Capacitive Deionization (Fb CDI) was selected, and the dissolved ions were monovalent. The effect of temperature on the amounts of desalination, the charge displaced between the electrodes, and the cell performance coefficient were investigated. Donnan’s model was modified to model the Electrical Double Layer (EDL). The modified model involves the electrical diffusion layer within the micro-pores and the electric capacitance in the Stern layer. To investigate the primary functional parameters of capacitive deionization, the inlet fluid temperature was changed from 5 to 45 °C. The simulation results indicated that the amount of desalinated water or salt absorbed in electrodes and the amount of electric charge displaced between the electrodes decreased by the temperature while the cell performance coefficient or efficiency remained constant.