Capacitive deionization characteristics of nanostructured carbon aerogel electrodes synthesized via ambient drying

RF (resorcinol formaldehyde) organic aerogels were cost-effectively prepared by solvent exchange using acetone and then ambient drying of RF wet gels obtained from the sol-gel method of the starting solution of RF. The carbon aerogel electrodes for the capacitive deionization (CDI) process with high specific surface area (similar to 610 m(2)/g), high specific capacitance (similar to 220 F/g), high porosity (similar to 80%), low bulk density (similar to 0.50 g/cm(3)), and high electrical conductivity (similar to 13.2 S/cm) have been synthesized via pyrolyzing RIF organic aerogels at 800 degrees C in nitrogen atmosphere. The CDI unit system containing a pair of carbon aerogel electrodes showed the maximum ion removal efficiency when the 50 mg/L NaCl solution was recycled at the volume flow rate of 400 mL/min under the applied voltage in the range of 1.5-1.7 V. Under the optimum operating conditions of the CDI unit system, the NaCl removal efficiency of the CDI stack system composed of 6 unit cells was about 92.8% and 97.6% at 1.5 and 1.7 V, respectively. It was evaluated that the CDI process using carbon aerogel electrodes promised to be an effective technology for desalination.