Investigation of Capacitive Deionization; Performance Assessment Based on Operational Parameters and Single-Objective Optimization

Capacitive deionization (CDI) is an electrochemical sorption desalination technique used for the purification of brackish water to fulfill industrial and domestic demands. There are two operational models of CDI, i.e., constant current (CC) and constant voltage. In this paper, a parametric performance evaluation of CC CDI has been executed along with system-level optimization. Segregation of three major concerns for CC CDI (water quality, desalination efficiency, and commerciality) into performance parameters offered the multi-scope analysis of its performance. However, a contradiction of the system parameters (e.g., energy consumption increased while the effluent concentration decreased to achieve the desired level) called for inevitable trade-offs. The single-objective optimization methodology with genetic algorithm and particle swarm optimization delivered the most optimized operating condition for trade-off. However, to achieve the target effluent concentration as minimum as 3.4 mM, the influent concentration and flow rate should be restricted at 20 mM and 6 ml/min, respectively.