CHELATION PROPERTIES OF SOME CONDENSATION POLYMERS TOWARD SOME TRIVALENT LANTHANIDE IONS

The sorption properties of some condensation polymers; poly(galic acid-2,6-diylmethylene), polymer I, poly(piperazine-1,4-diylmethylene), polymer II, and poly(catechol-3,6-diylmethylene), polymer III, toward the trivalent lanthanide metal-ions, La^3+, Nd^3+, Sm^3+, Gd^3+, and Tb^3+ was investigated as a function of contact time, pH, and counter ion by complexometric titration using standard EDTA solution and xylenol orange as an indicator. For the three polymers, the highest metal-ion uptake was achieved at pH 7.0 and by using perchlorate as the counter ion. Results of the study revealed that polymer II has thehighest metal-ion uptake capacity, and that the metal-ion uptake follows the order: Tb^3+ Gd^3+ Sm^3+ Nd^3+ La^3+.