By Wasudeo B. Gurnule, Deepti B. Patle
Copolymer resin (o-APUF) was synthesized by the condensation of o-aminophenol[AP] and urea[U] with formaldehyde[F] in the presence of an acid catalyst and using varied molar ratio of reacting monomers. Copolymer resin compositions have been determined on the basis of their elemental analysis and the number average molecular weight of o-APUF copolymer was determined by conductometric titration in non-aqueous medium. Viscometric measurements in dimethyl sulphoxide have been carried out with a view to ascertain the characteristic functions and constants. UV-VIS, FT-IR and 1H NMR spectra were studied to elucidate the structure. Ion-exchange properties of these resin were studied by batch equilibrium method for Fe3+, Cu 2+, Ni2+, Co2+, Zn2+, Cd2+, Hg2+ and Pb2+ ions over the pH range, 1.5 to 6.5 and in media of various ionic strengths. In the presence of nitrate, perchlorate and chloride ions the uptake of Fe(III), Cu(II), Hg(II), Zn(II), and Pb(II) ions increasing with increasing concentration of electrolytes, whereas in the presence of sulphate ions, the amount of above mentioned ions taken up by the copolymer resin decreases with increasing concentration of electrolyte. The resin shows a higher selectivity for Fe3+ ion over any other ions. Study of distribution ratio as a function of pH indicates that the amount of metal ion taken by resin is increases with the increasing pH of medium. The surface morphology of the copolymer resin was examined by scanning electron microscopy and it establishes the transition state between crystalline and amorphous nature.
Key Words : Copolymer resin, Chelating properties, Batch equilibrium, Ion-exchangers, Distribution ratio, Metal ion uptake.
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