Adsorption studies of silver (+1) on bentonite

Adsorption of silver on bentonite has been studied by using batch-technique, Distribution Co-efficient (K-d's) wee determined for bentonite silver solution system in natural water as a function of contact time,pH, adsorbent & adsorbate concentration and temperature. Adsorption data have been interpreted in terms of Freundlich and Langmuir equations. Thermodynamics parameters for the adsorption have been determined at three temperatures. The value of DeltaH* = -3.62 KJ/mol and DeltaG* = 3.61 KJ/mol at 298K suggests that the adsorption of silver on bentonite is an exothermic process. The desorption studies at low given silver loading on bentonite shows that significant %age of the element is irreversibly adsorbed due to the fixation of the silver by isomophous replacement in the crystal lattice of the adssorbent.