Kinetic Behavior of Lightly Crosslinked Chelating Resins Containing Amidoxime Groups for Batchwise Adsorption of UO2 2+

Abstract

Lightly crosslinked poly(acrylonitrile-co-divinylbenzene) beads (RN-5) have been synthesized by suspension polymerization. The use of dichloroethane and chloroform as a porogen produced lightly crosslinked copolymer beads having highly porous structures. The chelating resins containing amidoxime groups (RNH-5) have been prepared by the reaction of copolymer beads with NH₂OH in MeOH. The resulting chelating resins have been used in the batchwise adsorption of UO₂ ²⁺ from nitrate solutions containing 0.01 mol·dm⁻³ UO₂ ²⁺ at pH 3.25. In order to get some measure of the relative performance of each resin in kinetic terms, the extraction of UO₂ ²⁺ was monitored with time and some adsorption profiles were obtained. An increase in porogen content resulted in a marked increase in the batchwise adsorption of UO₂ ²⁺. Alkaline treatment allowed a high swelling and hence rapid accessibility of UO₂ ²⁺ to the ligands. Even after 30 minutes, the alkali-treated resins were 50% loaded.