Adsorption of cadmium (II) and nickel (II) on dolomite powder

In this work, the adsorption behavior of cadmium and nickel was studied using natural dolomite powder. The adsorption experiments were carried out to investigate adsorption parameters including metal ions concentration, solution pH, contact time, and temperature using a batch technique. The equilibrium adsorption isotherm data of the metal ions adsorption were best described by Freundlich, Langmuir, and Dubinin-Radushkevich isotherm models. The adsorption capacity was obtained 1.46 and 1.70 mg/g for cadmium and nickel, respectively. Kinetic studies revealed that the initial uptake was rapid and equilibrium was established in, 120 and 105 min for Cd(II) and Ni(II), respectively. The results showed that the data followed the pseudo-second-order reaction. Thermodynamic analysis showed that the adsorption of the metal ions on dolomite is feasible and exothermic. The mean free energy values obtained using the Dubinin-Radushkevich model for the ions showed that the adsorption of nickel and cadmium ions onto dolomite occurs via a physical process for all the temperatures.