Chelating terpolymer resin: Synthesis, characterization and its ion-exchange properties

A new chelating terpolymer resin was synthesized from 8-hydroxyquinoline and salicylic acid with formaldehyde (QSF) by solution condensation technique in acid medium. The terpolymer resin was characterized by elemental analysis, infra-red and nuclear magnetic resonance (1H and 13C NMR) spectroscopy. The structure of the terpolymer was confirmed on the basis of spectral data. The thermogravimetric analysis (TGA) was performed to evaluate the thermal degradation characteristics and also to calculate the kinetic parameters such as activation energy and the order of the reaction. The average molecular weight and the polydispersity index for the terpolymer were calculated by gel permeation chromatography (GPC). The surface characteristics were examined through scanning electron microscopy (SEM) at different magnifications. A batch equilibrium method was employed to study the selectivity and sorption capacity of the terpolymer resin towards certain divalent metal ions such as Pb2+, Zn2+, Cu2+, Ni2+, Ba2+, Co2+ and Mn2+ in various electrolyte concentrations, wide pH ranges and different time intervals. From the ion-exchange studies, the QSF terpolymer was found to be an excellent cation exchanger for selective metal ions.

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► A novel 8-hydroxyquinoline–salicylic acid–formaldehyde terpolymer has been synthesized.
► QSF resin has excellent ion-exchange characteristics and it can be reused.
► It possesses higher thermal degradation stability.
► SEM images show high porosity in the surface of the resin evidences the effective adsorption.