The investigation of heavy metals adsorption by using phthalhydrazide-immobilized-bentonite

In this study, phthalhydrazide, which was an organic compound, was immobilized onto natural bentonite. The immobilization of phthalhydrazide was tested by using FTIR spectroscopic and thermal analysis techniques. pH experiments were carried out between 1 and 5.5 in order to determine the maximum adsorption capacities of natural bentonite and phthalhydrazide-immobilized-bentonite for Cu2+ and Pb2+ ions. To determine the adsorption kinetics Lagergren-first-order, pseudo-second-order, Elovich kinetics and intraparticle diffusion models were applied to the experimental data. The pseudo-second-order kinetic model was able to provide the best description for the adsorption of Cu2+ and Pb2+ ions onto natural bentonite and phthalhydrazide-immobilized-bentonite. The validity of the pseudo-second-order kinetic model in this study was quantitatively performed by using normalized standard deviation (?q%). The isotherm studies were also done to understand the adsorption phenomenon. Beside, to determine the reusability of phthalhydrazide-immobilized-bentonite for Cu2+ and Pb2+ ions, desorption studies were performed. The obtained results indicate that natural bentonite was a more suitable adsorbent than phthalhydrazide-immobilized-bentonite for Pb2+ ions, whereas phthalhydrazide-immobilized-bentonite was a respectable adsorbent for Cu2+ ions.