Adsorption behavior of lead ion on calix[4]arene tetracarboxylic acid impregnated resin

The resins impregnating calix[4]arene tetracarboxylic acid into XAD-7 has been prepared to investigate adsorption behavior of lead ion. The leakage of the impregnated reagent to an aqueous solution is found to be negligible. The sequence in the adsorptive selectivity series for divalent metal ions on the present resin is as follows: Pb much greater than Cu > Zn > Ni approximate to Co. This sequence is also the same with that of the extractive selectivity series of p-t-octylcalix[4]arene as an extractant. The other adsorption properties of the resin for metal ions are similar to the extractive properties of the corresponding calix[4]arene tetracarboxylic acid. Maximum adsorption capacity of lead ion on the resin is found to be 0.33 mol kg(-1). For endurance test, even in eight times repetitive experiment of adsorption followed by elution of lead, the resin is devitalized and available for repeatability. Column chromatographic separation of lead and zinc ions as an industrial application is also carried out. Selective adsorption of trace amounts of lead ion over excess amount of zinc ion is achieved.