Isotherm and Kinetics Study of The Adsorption of Chromium (VI) From Aqueous Solution by Zizyphus Spina-christi Leaves Ash Nanoparticles

Existence of heavy metals in the water resources is of the major environmental problems in many communities. The purpose of this study is the research about chromium absorption on nanoparticles of Zizyphus Spina-christi leaves ash. After preparing of nanoparticles of Zizyphus Spina-christi leaves ash, various characteristics of absorbent such as SEM, FTIR, CHNSO and XRF were investigated. Then effect of initial pH, contact time and adsorbent dose on chromium adsorption efficiency was investigated. The results of kinetics adsorption were evaluated by kinetic models of pseudo-first order, pseudo-second order andintraparticle diffusion. Also experimental data were analyzed by using isotherm models of Langmuir, Freundlich and Sips. The results showed that at pH = 3, efficiency of absorption was high. In this study, equilibrium time occurred 180 minutes and the optimum adsorbent dosage for chromium adsorption with initial concentration of 10 mg/L was obtained 5 g/L. Based on the results obtained, the best kinetics model was Pseudo second-order and the best isotherm model was Sips. Adsorption capacity maximum of nanoparticles of Zizyphus Spina-christi leaves ash by using Langmuir model was estimated 411.2 mg/g.