Hydrophilic nano-porous carbon derived from egg whites for highly efficient capacitive deionization

[Display omitted] •An N doped hierarchically porous carbon was prepared from egg white foams.•The carbon has an ultra-high surface area, boosted conductivity and wettability.•Additional pseudo-capacitance could also be provided by these N doped active sites.•Advanced CDI performance has been achieved by the material. The design and preparation of electrode material with advanced desalination properties are key factors to the capacitive deionization (CDI) technique. Herein, a nitrogen (N) doped porous carbon has been successfully fabricated using whipped egg foam as precursor. It possesses a unique micro-mesopore structure with ultra-high specific surface area of 3277.96 m2 g−1, and abundant active adsorption sites from the surface doping. These features could not only provide hydrophilic property, but also good electronic/ions conductivities during the deionization processes, facilitating the pseudo-capacitance and total CDI performance. As a result, the obtained electrode material could deliver a high salt adsorption capacity of 26.67 mg g−1 and fast salt adsorption rate in 500 mg L−1 NaCl solution at an applied voltage of 1.2 V, which could be considered a feasible electrode material for CDI.