Ion-exchange properties of 2,2'-dihydroxybiphenyl - urea - formaldehyde terpolymer resins

A number of resins have been synthesized by reacting 2,2'-dihydroxybiphenyl with urea and formaldehyde in presence of 2M HCl as catalyst, proved to be selective chelating ion-exchange resins for certain metals. Chelation ion-exchange properties of these terpolymer were studied for Fe 3+, Cu 2+, Ni 2+, Co 2+, Zn 2+, Cd 2+ and Pb 2+ ions. A batch equilibrium method has been employed in the study of the selectivity of metal ion uptake involving the measurements of the distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The terpolymer showed higher selectivity for Fe 3+, Cu 2+ and Ni 2+ ions than for Co 2+, Zn 2+, Cd 2+ and Pb 2+ ions.