Adsorptive Removal of Ni (II) from Aqueous Solutions using Carbon Derived from Mulberry Wood Sawdust

Abstract

Carbon derived from mulberry wood sawdust treated with sodium hydroxide was investigated through adsorption process for the removal of Ni (II) from aqueous solution. Sawdust carbon (SDC) and chemically treated sawdust carbon (CSDC) were characterized using SEM, FTIR. The effect of variables like pH, contact time, initial Ni (II) concentration, sorbent dose and temperature were studied. Maximum % uptake of Ni (II) ion (86.50 %) was achieved at pH 7. The maximum Ni (II) removed from aqueous solution in 70 min after the starting of each experiment. The batch adsorption kinetic studies have been carried out and the applicability of the Freundlich and Langmuir adsorption isotherms were conducted at room temperature for the Ni (II) in aqueous system. The adsorption data fit well in Langmuir adsorption model. The pseudo-first-order, pseudo-second-order, intraparticle diffusion and Elovich models were tested for kinetic study. The data shows that pseudo-second-order model (R2 > 0.99) was the best choice among the kinetic models for description of adsorption of Ni (II) on CSDC. The spontaneous and endothermic nature of the sorption process was revealed from thermodynamic parameters such as standard entropy, free energy and enthalpy. The effect of some common alkali and alkaline earth metal ions were also studied which showed that the presence of these ions have no effect on the sorption of Ni (II). The results showed that CSDC has the potential to be used as a low cost sorbent for the removal of Ni (II) from aqueous solutions.