Sorbent Characteristics of Montmorillonite for Ni2+Removal from Aqueous Solution

Abstract

Sorption of Ni 2+ in aqueous solution was studied using montmorillonite. The experimental and equilibrium data fitted well to the Langmuir isotherm model. From the kinetics data for nickel sorption onto montmorillonite, the diffusion of Ni 2+ inside the clay particles was the dorminant step controlling the sorption rate and as such more important for Ni 2+ sorption than the external mass transfer. Ni 2+ was sorbed due to strong interactions with the active sites of the sorbent and the sorption process tends to follow the pseudo second-order kinetics. Thermodynamic parameters (∆G°, ∆ H°, and ∆S°) indicated a non spontaneous and endothermic adsorption process while the positive low value of the entropy change suggests low randomness of the solid/solution interface during the uptake of Ni 2+ by montmorilionite. Heavy metals such as Ni 2+ in aqueous bodies can effec