Selective extraction of U(VI) over Th(IV) from acidic streams using di-bis(2-ethylhexyl) malonamide anchored chloromethylated polymeric matrix

A new chelating polymeric sorbent has been developed using Merrifield chloromethylated resin anchored with di-bis (2-ethylhexyl) malonamide (DB2EHM). The modified resin was characterized by 13 C CPMAS NMR spectroscopy, FT–NIR–FIR spectroscopy, CHN elemental analysis and also by thermo gravimetric analysis. The fabricated sorbent showed superior binding affinity for U(VI) over Th(IV) and other diverse ions, even under high acidities. Various physio-chemical parameters, like solution acidity, phase exchange kinetics, metal sorption capacity, electrolyte tolerance studies, etc., influencing the resin’s metal extractive behavior were studied by both static and dynamic method. Batch extraction studies performed over a wide range of solution acidity (0.01–10 M) revealed that selective extraction of U(VI) could be achieved even up to 4 M acidity with distribution ratios ( D) in the order of ∼10 3. The phase exchange kinetics studies performed for U(VI) and Th(IV) revealed that time duration of 99.5% extraction. But similar studies when preformed for trivalent lanthanides gave very low D values (