Desalination by capacitive deionization process using nitric acid-modified activated carbon as the electrodes

In this work an activated carbon modified by nitric acid has been used as the electrodes in capacitive deionization (CDI) process for the desalination of an aqueous electrolytic solution. The experimental results have shown that the modification could greatly increase the salt removal from the solution. The desalination efficiency was increased about 15%, and the desalination kinetics was improved in the form of rate constant from 0.09208 to 0.09922. It has been found that the modification greatly increased the oxygen-containing functional groups on the surfaces of activated carbon, leading to the increases of the capacitance and the reduction of the charging resistance, which might be attributed to the improvement of the desalination. (C) 2014 Elsevier B.V. All rights reserved.