Relation between operating parameters and desalination performance of capacitive deionization with activated carbon electrodes

Electrosorptive batch experiments were conducted for the development of a statistical model to describe the relation between operating parameters and desalination performance of capacitive deionization (CDI) with activated carbon electrodes. Results showed that the statistical model reproduced the data well, with both regression and verification R-2 values above 0.85. The exponents in the statistical model, shown as 2.79, -0.45, and 1.05 for the applied voltage, spacer thickness, and retention time, respectively, revealed the importance of each factor in the correspondingly examined range. In addition, the effects of interactions between the factors were judged as significant, which could be explained by the electrical double-layer theory. The influence of initial salt concentration could be best characterized by the Langmuir isotherm. This work demonstrates that direct modeling of desalination performance with operating parameters is feasible and the results can be used to guide practical engineering applications.