Removal of Ni(II) from aqueous solution by adsorption onto hazelnut shell activated carbon: equilibrium studies

Activated carbon prepared from hazelnut shell was used as an adsorbent for the removal of Ni(II) from aqueous solution. Batch mode adsorption studies were carried out by varying initial metal ion concentration, agitation speed, temperature and particle size. A contact time of 180 min was required to reach equilibrium. The equilibrium data were analysed using the Langmuir, Freundlich and Temkin isotherms. The characteristic parameters for each isotherm were determined. The Langmuir isotherm provided the best correlation for Ni(II) onto the activated carbon. Thermodynamical parameters revealed that the adsorption of Ni(II) is exothermic in nature.