STUDIES ON AG+ ADSORPTION USING TWO NEW LIGNOCELLULOSIC MATERIALS BASED ON POPULUS ALBA L. AND ROBINIA PSEUDOACACIA L.

The adsorption of Ag(+)ions onto lignocellulosic materials based on two fast-growing tree species Populus alba L. (poplar) and Robinia pseudoacacia L. (black locust) was studied. Chemical analyses were performed to establish the composition of the obtained materials. Texture parameters were calculated by means of low temperature nitrogen adsorption. The adsorption mechanism was examined using IR, SEM, EPR and XPS spectroscopy. The effects of contact time, acidity and initial Ag+ ion concentrations were investigated. In both cases, the adsorption was significantly affected by the pH value. Experimental equilibrium data were fitted to the Langmuir, Freundlich and Dubinin-Radushkevich models and the corresponding constants were calculated. The obtained results revealed that the examined waste lignocellulosic materials can be used as adsorbents for Ag+ ions.