ASSESSMENT OF THE ADSORPTION KINETICS, EQUILIBRIUM AND THERMODYNAMICS FOR THE POTENTIAL REMOVAL OF NI2+ FROM AQUEOUS SOLUTION USING WASTE EGGSHELL

In this study, Ni2+ sorption onto the waste eggshell was investigated under different operational conditions. Results indicated that the eggshell could be successfully used to remove Ni2+ ions from the water. Quick sorption process reached to equilibrium in about 2 hours with maximum sorption at pH 7.0. Based on the experimental data, Langmuir isotherm model with the q(m) value of 1.845mg Ni2+/g eggshell was observed. The pseudo-second-order model provided the best correlation coefficient in comparison with other models. The calculated q(e) values derived from the pseudo-second-order for sorption of Ni2+ ions were very close to the experimental (q(exp)) values. Such thermodynamic parameters as G degrees, H degrees, and S degrees were determined in order to predict the nature of adsorption. Results indicated that the adsorption of Ni2+ onto the eggshell was endothermically supported by the increasing adsorption of Ni2+ ions with temperature.