Investigation of Isotherm and Kinetic of Nickel Adsorption by Acorn Ashes from Aqueous Solutions

One of the major pollutants for environment is nickel and high concentrations of it cause lungs cancer, nasal and bone sinuses. Thus, for protection human's health and environment, it is necessary to remove excess nickel ions from industrial wastewater. The aim of this study was the evaluation of acorn ashes efficiency for the removal of nickel ions. This study was performed experimentally. In this study, the effect of pH, retention time, adsorbent mass and initial concentrations of nickel ions have been evaluated. The experimental isotherm data were analyzed using the Langmuir, Freundlich and Temkin equations. Also, to determining the best adsorption kinetic model for nickel ions onto acorn ashes, the pseudo first-order, pseudo second-order and Elovich equations were used. Experimental data indicated that the adsorption capacity was dependent on pH of the solution, retention time, adsorbent mass and initial nickel ions concentration. The optimum pH for adsorption of nickel ions was 7.0. With increasing of adsorbent mass and retention time, adsorption efficiency increased while with increasing of initial nickel ions concentration, adsorption efficiency decreased. The results showed that the experimental data much better fit with the Freundlich isotherm. The best model for the adsorption kinetic was shown with the pseudo-second-order kinetic model. The present study indicates that the Iranian acorn (Quercus persica) ashes can be used as an effective and environmentally friendly biosorbent for the removal of nickel (II) ions from aqueous solutions.