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

Abstract

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.

Keywords: Amidoxime; Chitosan; Cyanoacetic acid; Ion-imprinting; Uranyl ion.