Synthesis and chelation ion exchange properties of 2, 4-dihydroxyacetophenone-biuret-formaldehyde terpolymer resin

Abstract

The terpolymer resin 2, 4-dihydroxyacetophenone-biuret-formaldehyde has been synthesized by the condensation of 2, 4-dihydroxyacetophenone and biuret with formaldehyde in 2:1:3 molar ratios in presence of 2<i style="">M</i> hydrochloric acid as catalyst. UV-visible, IR and proton NMR spectral studies have been carried out to elucidate the structure of the resin. The terpolymer has proved to be a selective chelating ion exchange polymer for some metals. Chelating ion exchange properties of this polymer have been studied for Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺and Pb²⁺ ions. Batch equilibrium method has been employed to study the selectivity of metal ion uptake and distribution coefficient over a wide <i style="">p</i>H range and in media of varying ionic strengths. The polymer shows higher selectivity for Fe³⁺and Cu²⁺ ions than for Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺ and Pb²⁺ ions. Study of distribution ratio as a function of <i style="">p</i>H indicates that the amount of metal ion uptake by resin increases with the increasing <i style="">p</i>H of the medium.