Preparation, characterization and Cr(VI) adsorption evaluation of NaOH-activated carbon produced from Date Press Cake; an agro-industrial waste

Date Press Cake (DPC) is an inevitable by-product of date processing industries and may pose environmental problems if not managed properly. In this study, DPC was converted into activated carbon using solid NaOH under various activation conditions. The prepared activated carbon showed high specific surface area (2025.9 m2 g−1) and microporous texture (86.01%). It was successfully applied for the adsorption of Cr(VI) from aqueous solutions with maximum monolayer adsorption capacities as high as 282.8 mg g−1 (pH = 2) and 198.0 mg g−1 (pH = 5). The kinetic and isotherm experimental data of Cr(VI) adsorption onto the activated carbon were best described by Elovich and Redlich-Peterson models, respectively. It was found that the Cr(VI) adsorption onto the DPC-derived activated carbon was predominantly a chemisorption process with limited desorption rates (below 50%). Overall, Date Press Cake could be considered as an abundant and renewable agro-industrial precursor for the production of high quality activated carbon.