Preparation and characterization of groundnut shell-based activated charcoal

Abstract

Groundnut shell, an agricultural waste was used as a precursor for the preparation of activated charcoal using zinc chloride as a chemical activating agent. The results of the optimization studies showed that the activated charcoal had best iodine adsorption capacity at 1.0 mol dm^-3 activator’s concentration, 2:1 impregnation ratio, 70 ℃ impregnation temperature, 12 hr impregnation time, 500 ℃ activation temperature, and 2hr activation
time. The surface chemistry of the adsorbent was studied by Fourier transform infra-red spectroscopy and scanning electron microscopy–energy dispersive X-ray spectroscopy. The activated charcoal was found to contain porous structures with adsorption capacities significantly correlated with iodine value, porosity, and surface area. The surface morphology of the activated charcoal was altered as compared with the un-activated product, signifying that the adsorbent had been chemically modified. The disappearance of some functional groups and shift in some absorption bands were further indication that surface structural modification took place during activation and carbonization.This research has revealed that groundnut shell could be employed for the production of an alternative adsorbent which can be utilize for filtration and detoxification of impure water, treatment of effluent and wastewater, adsorption of pesticides, heavy metals and dyes from aqueous media.