Carbon aerogels through organo-inorganic co-assembly and their application in water desalination by capacitive deionization

We report the preparation of a carbon aerogel (CA) material utilizing the simultaneous co-assembly of organic and inorganic precursors, having a high Brunauer-Emmet-Teller surface area of 2600 m2/g, through a one-step sol-gel process. This CA was characterized using different spectroscopic and microscopic techniques. The as-synthesized CA with its tunable porosity, high mechanical strength, transport property and electrical conductivity was found to be a suitable candidate for water desalination via capacitive deionization (CDI). The optimum working potential for CDI was in the range of 1.2-1.4 V. The material was tested for the removal of different ions of varying charges and the experiment was performed for multiple cycles. The result showed high adsorption capacity of 10.54 mg/g for Cl− in laboratory batch experiments compared to 3-4 mg/g reported for most of the CDI materials. The materials were also characterized after adsorption/desorption cycles. Adsorption was physical in nature and the ions desorbed completely after reversing the polarity. The result showed that the material can be used for multiple cycles without any change in its spectroscopic and adsorption properties.