BEHSA grafted polymer for selective extraction of U(VI), Th(IV) and La(III) from acidic matrices and environmental samples – a green process

Abstract

SummaryA new class of polymeric resin called MCM-BEHSA, for extraction of U(VI), Th(IV) and La(III) was synthesized by grafting Merrifield chloromethylated polymer withN,N-bis-(2-ethyl-hexyl)-succinamic acid. The chemical modifications at each step of the grafting was confirmed by FT-IR spectroscopy, CPMAS solid state NMR spectroscopy, CHN elemental analysis and also by Thermo Gravimetric analysis. All the parameters influencing the quantitative metal ion extraction were optimized by both static and dynamic methods. The resin showed good extractability over a wide range of acidity (0.01-10 M) with fast exchange rate (saturation possible within 20 minutes) and high sorption capacities for U(VI), Th(IV) and La(III). Quantitative metal desorption was achieved by using 0.5 M (NH4)2CO3for all the analytes. A significant feature of this grafted polymer was its ability to extract Th(IV) from very high nitric acid concentrations. Interference studies with commonly encountered metal ions, rare earth ions and electrolytes showed very high tolerance limit for those ions. Enrichment factor values of 400, 550 and 350 with limit of quantification (LOQ) as 10 ng ml-1, 10 ng ml-1and 20 ng ml-1were observed for U(VI), Th(IV) and La(III), respectively. All the analytical data were within 3.2% rsd, reflecting the reproducibility and reliability of the developed method.