Selection of chemical activating agent for the synthesis of activated carbon from coconut shell for enhanced dye treatment - its kinetics and equilibrium study

Abstract

In this work coconut shell (CS) and rice husk (RH) were used for the synthesis of activated carbon (AC). Conventional activating agents such as KOH, HNO3 and H3PO4 were chosen for synthesis of AC. The effective surface area obtained for the prepared AC using activating agents was evaluated based on iodine number test. Further the synthesized AC with more active pore sites obtained at optimal physical and chemical parameters has been characterized by FTIR, XRD and SEM respectively. It was found that for 2 N concentration of KOH and with an impregnation time of 20 h gives AC of high specific surface area with more active pore sites for the adsorbents. The activation time and the temperature to obtain the same are 60 min & 700 °C respectively. The efficacy of prepared AC was evaluated by using it for the deletion of crystal violet dye in an aqueous solution by considering effect of primordial parameters such as contact time, adsorbent dosages, concentration and pH Further, Langmuir & Freundlich adsorption isotherm models were used to verify the obtained pore volume, specific surface area, adsorption capacity & adsorption intensity. The adsorption kinetics was validated & analyzed for the prepared AC using pseudo first and second order kinetic model.