Evaluation of isotherm models and competitive adsorption of Cd+2 and Ni+2 on Zeolite-waste composite

zeolite-waste composite was used as adsorbent for the removal of heavy metal ions from wastewater. The isotherm models and competitive adsorption were investigated. The adsorption isotherm models of Langmuir, Freundlich, Temkin, Dubinin–Radushkevich (D-R) and Redlich-Peterson have been applied on heavy mteals adsorption by the composite. The characterization of composite was studied by FTIR, SEM, XRF and XRD methods. The adsorption data for Cd and Ni ions were fitted with the Langmuir and Freundlich isotherm models, respectively. The competitive adsorption ability of heavy metal ions in the binary system on the composite showed that the Cd ions had a synergistic effect on the adsorption of Ni ions on the composite. However, the presence of Ni ions in the solution reduced the adsorption of Cd ions on the surface of the composite Keywords: adsorption, zeolite, Iron fly ash, heavy metal, isotherm model, competitive adsorption.