LIGANDS SORPTION STUDIES ON TRANSITION-METAL ION LOADED AMBERLITE IRC-50

Ligands sorption of ammonia, diethanolamine, and triethanolamine on th e cation exchanger Amberlite IRC-50 having Cu2+, Ni2+, and Zn2+ ions w as studied as a function of temperature 290-318 K and different initia l concentrations 1-500 mmol.L-1. Sorption was found to follow the orde r Cu2+ > Zn2+ > Ni2+ and ammonia > diethanolamine > triethanolamine. D esorption of metal cations from the exchanger to the aqueous phase was also observed when the temperature of the system was increased. The r esults were explained in terms of ligand sorption and ion exchange, wh ich were found to be dependent upon the stabilities of the complexes i nside the resin and in the aqueous solution and the basicity and hydro phobicity of the ligand involved. The ratio of metal released/amine so rbed was determined which indicated two possible mechanisms of ligand sorption. The data were explained with the help of mass action law. IR studies also confirmed the presence of metal complexes and metal-amin e complexes inside the resin.