Amidoxime modified chitosan based ion-imprinted polymer for selective removal of uranyl ions

Ion-imprinting strategy was utilized in the development of UO2(II) imprinted amidoxime modified chitosan sorbent (U-AOCS) that can selectively remove UO2(II) from water. First, cyanoactic acid was linked to the chitosan –NH2 groups and then the inserted –CN groups were converted into amidoxime moieties, which chelate the UO2(II) ions and then the polymer chains were cross-linked by glyoxal. The UO2(II) ions have been then eluted leaving their matching recognition sites. The prepared U-AOCS along with the control NIP displayed maximum capacities toward the UO2(II) ions around 332 and 186 mg/g, respectively, and the isotherms were interpreted better by the Langmuir model in both adsorbents. Moreover, the selective uptake of the uranyl ions in multi-ionic aqueous solutions containing the tetravalent Th(IV) ions, trivalent Al(III), Eu(III), and Fe(III) ions, beside the divalent Pb(II), Co(II), Ni(II), Cu(II) ions confirmed the successful creation of a considerable UO2(II) ions selectivity in the U-AOCS construction. In addition, the U-AOCS adsorbent displayed economic feasibility by maintaining around 95 % of its initial efficiency after the regeneration and reuse for 5 adsorption/desorption cycles.