Promising honeycombed cork activated carbon for high desalination performance brackish water treatment

Abstract

Cork activated carbon (CAC), derived from natural cork, was successfully prepared through two steps of carbonation and activation, and used for desalinating brackish water. The CAC presents a uniform honeycomb structure composed of porous carbon nanoflakes (200–300 nm) and large specific surface area (SSA) (2680 m² g⁻¹), offering transport channels and a large number of adsorption sites to NaCl solution. The CAC showed excellent capacitance (116 F g⁻¹), small internal resistance and better charge-discharge performance. Moreover, the optimized CAC showed high desalting capacity (9.44 mg g⁻¹), charge efficiency (46.72 %), and lower energy consumption (54.19 Wh m⁻³) in the desalination process, superior to that of the reported biomass-based activated carbons, which can be attributed to the stable honeycomb structure, high microporous volume (0.86 cm³·g⁻¹) and large pore size (2.43 nm). This investigation demonstrates the potential application of cork granules-based CAC electrodes in the field of desalination.