New insight into the performance analysis of flow-electrode capacitive deionization by varying the operation voltage

In the flow-electrode capacitive deionization (FCDI), the highly activated porous carbon electrodes of slurry phase flows through the channels of current collectors and adsorbs the salt ions when a voltage is applied. In this study, the effect of voltage on the performance of a FCDI cell is experimentally investigated. The voltage is applied on the top corner of a FCDI cell (Vapply) and simultaneously the voltage of central cell (Vcell) is measured. The experiments were conducted by applying voltages from 0.6 to 3.9 V. The experimental results show that the difference between Vapply and Vcell is a function of salt concentrations of the feed water. The higher voltages (Vapply>1.2V) can be used for increasing the salt removal efficiency (E) for higher salt water concentrations without electrolysis. Also, the results show that E increases along with the applied voltage. A series of pH measurements were done in regard to investigation of electrolysis point of the setup.