Adsorption kinetics for removal of thiocyanate from aqueous solution by calcined hydrotalcite

Calcined hydrotalcite is a potential ion exchanger/adsorbent which can be used to remove toxic anions from contaminated water. The adsorptive removal of thiocyanate from aqueous solutions by calcined hydrotalcite was investigated in a batch mode. The influence of initial thiocyanate concentration, adsorbent concentration and temperature on the kinetics of thiocyanate removal was tested in kinetic runs. Three kinetic models were used to fit the experimental data, and it was found that the pseudo-second-order kinetics model is most appropriate to describe the adsorption kinetics. A Langmuir isotherm was used to fit the equilibrium experiments, and the saturated adsorption capacity was approximately 96.7 mg/g, under the experimental conditions. The calculated activation energy for the process was 48.9 kJ/mol.