Design of ion-imprinted cellulose-based microspheres for selective recovery of uranyl ions

Herein, cellulose was selected as the raw material for the production of sorbent microspheres for the selective separation of uranyl (UO22+) ions by ion-imprinting technique due to their low cost, biodegradability, and renewability. To begin, an amidoxime cellulosic derivative (AOCE) is synthesized by a Michael addition followed by an amidoximation reaction, both of which are homogeneous reactions. In the end, microspheres of ion -imprinted U-AOCE sorbent were made by mixing the developed AOCE derivative with UO22+, crosslinking the UO22+ polymer complex with glyoxal, and eluting the coordinated ions with H+/EDTA. U-AOCE smartly recog-nized the target ions for fitting the cavities generated during the UO22+-imprinting process, resulting in a much greater adsorption capacity of 382 +/- 1 mg/g and enhanced adsorption selectivity for UO22+. A pseudo-second -order model fit the data well in terms of kinetics, while the Langmuir model adequately explained the iso-therms, indicating chemisorption and adsorption via UO22+ chelation. The coordination between UO22+ and both the-NH2 and-OH groups of the amidoxime units is the primary adsorption process, as shown by NMR, XPS, and FTIR studies. For UO22+ biosorption from aqueous effluents, the results of this study deliver new guidance for the design of biosorbents with high removal capability and excellent selectivity.

Automated summary

Cellulose was used as raw material for the production of sorbent microspheres for selective separation of uranyl ions. An amidoxime cellulosic derivative (AOCE) was synthesized by Michael addition followed by amidoximation reaction, and microspheres of ion-imprinted U-AOCE sorbent were made by crosslinking the UO22+ polymer complex with glyoxal and eluting the coordinated ions with H+/EDTA. The adsorption capacity of U-AOCE was significantly higher with enhanced adsorption selectivity for UO22+. The primary adsorption process involved coordination between UO22+ and the-NH2 and-OH groups of the amidoxime units.