Equilibrium isotherm studies of copper and zinc removal from model solutions using natural and alkaline treated hornbeam sawdust

In the present study, sawdust an industrial by-product available in large quantities as sorbent material was studied. The removal adsorption capacity of Cu(II) and Zn(II) from aquatic solutions was obtained. The batch experiments were carried out to determine the effect of initial concentration of copper/zinc solution at pH=4.0 onto natural hornbeam and hornbeam modified with NaOH and KOH. The Fourier transform infrared spectroscopy (FTIR) determined the changes in functional groups after the modification of sawdust. The equilibrium data were fitted with four isotherm models - Langmuir, Freundlich, Tempkin and Dubinin– Radushkevich. The Langmuir model was found to be most suitable and the maximum adsorption capacity obtained for modified hornbeam sawdust was 2 to 4-times higher as in natural one for both heavy metals.