Synthesis of Ion-imprinted materials with amidoxime groups for enhanced UO22+ adsorption

Abstract

Ion imprinted polymer (IIP) of mesoporous nature was prepared for uranyl ion (template) in two steps:(i) by formation of ternary (benzamidoxime (BAOX) and 4-vinylpyridine) complex in 2-methoxy ethanol as porogen and (ii) by thermally copolymerizing them with methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the crosslinking monomer using 2,2′-azobisisobutyronitrile as initiator. The imprinted particles were leached by HCl 2 mol L−1 to obtain leached materials which then remove uranyl ions selectively from aqueous solutions. Non-imprinted polymer (NIP) was also similarly prepared under identical experimental conditions exactly as the IIP but in the absence of template ions.The above synthesized IIP (both unleached and leached) and NIP materials were characterized by using SEM, FT-IR, UV–Vis and BET-surface area and pore size analysis. The optimal pH for quantitative removal is 6.0 and the IIP materials offered either higher or comparable retention capacity 125 mg g−1 (C0 = 100 mg L−1) with respect to most of the hitherto prepared uranyl IIP materials. Further, the imprinting and amidoxime groups effect was noticed in the experimental variables and selectivity characteristics.