Solid Phase Extraction, Preconcentration and Sequential Separation of U(VI), Th(IV), La(III) and Ce(III) by Octa-O-methoxy resorcin[4]arene based Amberlite XAD-4 Chelating Resin

Amberlite XAD-4 was covalently linked with octa-O-methoxy resorcin[4]arene through N=Nto form chelating resin, which has been duly characterized and successfully used for separation and preconcentration of rareearth metal ions like U(VI), Th(IV), La(III) and Ce(III). Various physiochemical parameters like pH, flow rate, sorption capacity, breakthrough studies, distribution coefficient, preconcentration factor, concentration of eluting agents responsible for quantitative extraction of metal ions were optimized. The resin possessed good binding affinity towards U(VI), Th(IV), La(III) and Ce(III) under selective pH conditions and were quantitatively eluted with suitable eluants like HCl and HNO3. Amount of metal ions was determined by spectrophotometry or inductively coupled plasma-atomic emission spectrometry. Fast exchange kinetics and good breakthrough capacity of the resin lead to effective separation of metal ions from their binary and ternary mixture by column method on the basis of pH and eluting agents. The resin could be reused for 8-10 cycles with recoveries of analytes higher than 98%. Proposed method having analytical data with the relative standard deviation (RSD) < 2%, reflect upon the reproducibility and reliability of the method which has been effectively used for separation and determination of U(VI), Th(IV), La(III) and Ce(III) ions from monazite sand and standard reference materials.