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Kinetic studies and isotherm modeling for the removal of Ni2+ and Pb2+ ions by modified activated carbon using sulfuric acid



Acid Modified Activated Carbon (AMAC) was prepared by the chemical activation of corncob with 10 N sulphuric acid that can be used in Ni2+ and Pb2+ ions removal applications. The effect of adsorption experimental parameters such as the solution pH, adsorbent dose, contact time, initial metal ion concentration, and temperature studies on adsorption was investigated. The experimental data obtained from the studies on the effect of the initial metal ion concentration were fitted with Langmuir, Freundlich, and Redlich-Peterson adsorption isotherm models, using MATLAB R2009a. Similarly, the experimental data obtained from the effect of contact time were evaluated using the pseudo-first order, pseudo-second order, Elovich and Intra-particle diffusion adsorption kinetic models. Metal ions in adsorbed AMAC were characterized by FTIR, SEM, and EDX analyses to confirm the adsorption of the metal ions on their surface. The metal ion concentrations in the aqueous medium after and before adsorption were determined using Atomic Absorption Spectroscopy (AAS). Studies on the reuse and selectivity of the adsorbents were also carried out. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 844–854, 2014