Removal of Ni and Cd Ions from Aqueous Solution Using Iron Dust-zeolite Composite： Analysis by Thermodynamic, Kinetic and Isotherm Studies

摘要

To examine the effectiveness of iron dust-zeolite composite as an adsorbent for the removal of heavymetal ions from aqueous solutions, the adsorption isotherms, the kinetic, thermodynamic and optimum conditions,such as initial concentration, pH, contact time, adsorbent dosage and competitive adsorption conditions of heavymetals were investigated. The characterization of the composite was characterized via FTIR, SEM, XRF and XRDmethods. Kinetic results on the removal of heavy metal ions from aqueous solutions have been well described by thepseudo-second-order model. The adsorption data for Cd and Ni ions were fitted well with the Langmuir and Fretm-dlich isotherm models, respectively. The maximum adsorption capacities of iron dust-zeolite for Cd and Ni ions wereequal to 78.125 and 76.33 mg/g, respectively. The thermodynamic parameters such as enthalpy, entropy and freeenergy of adsorption of metal ions were determined. It was found that the process is endothermic, favorable andspontaneous. The competitive adsorption ability of heavy metal ions in the binary system on the composite showedthat Cd ions had a synergistic effect on the adsorotion of Ni and Ni ions had the negative effect on Cd adsorption.