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 Fe3+, Cu2+, Ni2+, Co2+, Zn2+, Cd2+ and Pb2+ 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 Fe3+, Cu2+ and Ni2+ ions than for Co2+, Zn2+, Cd2+ and Pb2+ ions.