Removal of cadmium metal ion (Cd2+) from its aqueous solution by aluminium oxide (Al2O3): A kinetic and equilibrium study

In this work, the effects of various experimental parameters on kinetics and equilibrium adsorption of Cd2+ metal ion from its aqueous solution on aluminium oxide (Al2O3) have been investigated using batch adsorption experiments. It has been found that the amount of adsorption of metal ion increases with initial metal ion concentration, contact time, and solution pH, respectively. It has also been found that amount of cadmium adsorption decreases with the amount of adsorbent and temperature, respectively. The kinetic adsorption experimental results have been analyzed using pseudo-first-order and pseudo-second-order kinetic models and the adsorption kinetics was found to follow a pseudo-second-order kinetic model. Rate constants at different initial concentrations, pH and at different adsorbent dosages have also been estimated. The experimental equilibrium data are fitted to both the Freundlich and Langmuir isotherms, respectively.