Surfactant-assisted freeze-drying synthesis of porous graphene for high-performance capacitive deionization

Abstract

Capacitive deionization (CDI) offers a green and efficient strategy of supplying sustainable clean water. Up to now, high-performance carbon electrode has been substantially pursued for developing advanced CDI technology. In this work, a surfactant-assisted freeze-drying route is reported for the facile synthesis of porous graphene electrode based on the hydrothermal reduction of graphene oxide with ascorbic acid in the presence of sodium dodecyl sulfate (SDS), followed by a freeze-drying treatment. The obtained porous graphene (defined as SRGO) is characterized by scanning electron microscopy, X-ray powder diffraction, elemental distribution analysis, Brunauer-Emmett-Teller adsorption isotherm and Raman spectra. The SRGO exhibits ideal pore size distribution and specific surface area, while the effects of the surfactant on the graphene structural properties are investigated. When used as CDI electrode, the SRGO shows a promising electrosorptive capacity of 5.38 mg·g−1, an excellent recyclability (64 min for regeneration), and a remarkable salt removal efficiency of 15.85%. This work opens up a facile and variable route to rationally tailor structural properties of graphene for water treatment applications.