In this study, hybrid aerogels containing carbon nanoparticles (CNP) and multi-walled carbon nanotubes (MWCNT) were synthesized via sol–gel method using resorcinol/formaldehyde precursors through a hydrolysis-condensation reaction mechanism. Porous carbonaceous structures were achieved by freeze-drying of the organic gels followed by controlled carbonization under an inert gas. The samples were characterized by various techniques such as FTIR, BJH, FESEM, CV, and EIS. The specific surface area and total pore volume of the aerogel sample were measured to be as high as 452 m2/ g and 0.782 cm3/ g, respectively, thus enhancing the electric double-layer formation. Electrochemical tests on the samples showed a large specific capacitance (212 F/g) and an excellent cyclic stability over 3000 cycles. Performance of the synthesized structures was subsequently assessed as electrodes in a capacitive deionization (CDI) process. At the operating conditions of 1.6 V voltage, flow rate of 20 mL/min, and NaCl concentration of 1000 mg/L a promising adsorption capacity around 42.08 mg/g was achieved.

Performance of CNT-CNP aerogel as electrode in capacitive deionization system
    Abstract
    1 Introduction
    2 Materials and method
        2.1 Materials
        2.2 Preparation of aerogel
        2.3 Fabrication of the CDI electrodes
        2.4 CDI set-up and experiments
        2.5 Characterization
    3 Results and discussion
        3.1 Characterization of the electrodes
        3.2 CDI performance
    4 Conclusion
    Acknowledgements 
    References

• N. Salman Tabrizi(Department of Energy, Materials and Energy Research Center, Karaj 31787/316, Iran)
• M. Salehi Taleghani(Department of Energy, Materials and Energy Research Center, Karaj 31787/316, Iran)