Preparation and characterization of activated carbons from Sterculia alata nutshell by chemical activation with zinc chloride to remove phenol from wastewater

Abstract

Nutshells of Sterculia alata, a forest waste, were used to prepare activated carbons by zinc chloride activation under four different activation atmospheres, to develop carbons with substantial capability, and to adsorb phenol from wastewater. Experiments were carried out at different chemical ratios (activating agent/precursor). Effect of carbonization temperature and time are the important variables, which had significant effect on the pore structure of carbon. Developed activated carbon was characterized by SEM analysis. Pore volume and surface area were estimated by Hg porosimetry and BET surface area analyses. The carbons showed surface area and micropore volumes of around 712 m2/g and 0.542 cm3/g, respectively. The activated carbon developed shows substantial capability to adsorb phenol from wastewater. The kinetic data were fitted to the models of intraparticle diffusion, pseudo-second order, and Lagergren model and followed more closely the pseudo-second-order chemisorption model. The isotherm equilibrium data were well-fitted by the Langmuir and Freundlich models. The maximum uptake of phenol was found at pH 3.5.