Adsorption of phenol from aqueous solutions using activated carbons prepared from Tectona grandis sawdust by ZnCl2 activation

Activated carbons prepared from Tectona grandis sawdust, a timber industry waste, have been examined for the removal of phenol from aqueous solutions. The activated carbon was prepared by zinc chloride activation under four different activation atmospheres, to develop carbons with well-developed porosity. Experiments were carried out at different chemical ratios (activating agent/precursor). Effects 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 585 m2/g and 0.442 cm3/g, respectively. The activated carbon developed showed substantial capability to adsorb phenol from aqueous solutions. The kinetic data were fitted to the models of Lagergren, pseudo-second-order and intraparticle diffusion, and followed closely the pseudo-second-order chemisorption model. The Freundlich and Langmuir isotherm models were well fitted. The solution pH markedly affected the sorption process. The maximum uptake of phenol was found to be 2.82 mg/g at pH 3.5.