The adsorption of heavy metal ions from synthetic single ion solutions was performed by using beech
sawdust. The pH value of water increases when rinsing the sawdust with distilled water. The maximum
sawdust adsorption capacity was achieved at pH > 4, while at pH < 2 it gets zero. The adsorption capacity
is almost equal for Cu2+ and Ni2+ (4–4.5 mg g−1), while for Zn2+ ions it is 2 mg g−1, thus exhibiting certain
selectivity the first two against zinc ions. Obtained results showed that the adsorption kinetics follows the
pseudo-second order reaction model. The adsorption equilibrium data show good fitting to the Langmuir
equation. The adsorption occurs via an ion exchange mechanism, where mostly calcium from the sawdust
cell structure was substituted by heavy metal ions.