Chelation ion-exchange properties of 2, 2'-dihydroxybiphenyl-urea-formaldehyde (2:1:3) resin

Abstract

The resin 2,2'-dihydroxybiphenyl-urea-formaldehyde [BPhUF], has been synthesized by the condensation of 2,2'dihydroxybiphenyl [BPh] and urea [U] with formaldehyde [F] in

2: 1:3 molar ratio in presence of 2<i>M </i>HCl as a catalyst. UV-Vis, IR and NMR spectral studies have been carried out to elucidate the structure of resin. Ion exchange properties of this resin have been studied by batch equilibrium method for Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺,Zn²⁺, Cd²⁺ and Pb²⁺ ions over the <i>p</i>H range, 1.5 to 6.5 and in media of various ionic strengths. In presence of chloride and nitrate ions, the uptake of Fe³⁺, Cu²⁺ and Ni²⁺ ions increases with increasing concentration of electrolyte while for Co²⁺,Zn²⁺, Cd²⁺ and Pb²⁺ ions, it decreases with increasing concentration of chloride, nitrate and sulphate ions. The resin shows a higher selectivity for Fe³⁺ ion over any other ion. Study of distribution ratio as a function of <i>p</i>H indicates that the amount of metal ion taken up by resin increases with the increasing <i>p</i>H of the medium.