Sequestration of Pb(II), Cd(II) and Ni(II) ions from aqueous Solution Using EDTA Modified Citrus sinensis Mesocarp.

Abstract

The potential of Citrus sinensis mesocarp as an adsorbent to remove Pb(II), Cd(II) and Ni(II) ions from aqueous solution was explored. The residual concentrations were determined using atomic absorption spectrophotometer (AAS). The effect of contact time, pH, initial metal ion concentration and temperature were studied. The study showed that the equilibrium contact time for the biosorption process was 100 minutes for all three metals and the maximum adsorption for Ni(II), Cd(II) and Pb(II) ions occurred at pH of 5, 6 and 7 respectively. The percentage removal of the metal ions increased with increase in temperature and initial metal ion concentration. The kinetics study of the biosorption process exhibited pseudo-second order kinetic models and the equilibrium data fitted well to Langmuir isotherms. The thermodynamic study revealed that the reaction was not spontaneous as Gibbs free energy ( G°) and standard entropy ( S°) values were negative for all the metal ions, but it was feasible and endothermic in nature as standard enthalpy ( H°) was positive. This study has demonstrated that Citrus sinensis mesocarp could be efficiently and effectively used to remove the metal ions from aqueous solution