Methacryloylamidoglutamic acid functionalized poly(2-hydroxyethyl methacrylate) beads for UO2+2 removal

A novel approach was developed to obtaining high uranium adsorption capacity utilizing 2-methacryloylamidoglutamic acid (MAGA) as a metal-complexing ligand. MAGA was synthesized by using methacryloyl chloride and glutamic acid. Spherical beads with an average size of 150-200 mum were obtained by suspension polymerization of MAGA and 2-hydroxyethyl methacrylate (HEMA) conducted in an aqueous dispersion medium. Poly(2-hydroxyethyl methacrylate methacryloylamidoglutamic acid) [p(HEMA-MAGA)] beads have a specific surface area of 56.7 m(2)/g. p(HEMA-MAGA) beads were characterized by swelling studies, FTIR and elemental analysis. The p(HEMA-MAGA) beads with a swelling ratio of 63%, and containing 3.5 mmol MAGA/g were used in the removal of UO22+ from aqueous solutions. Adsorption equilibrium was achieved in about 120 min. The adsorption of uranium(VI) ions onto pHEMA was negligible (1.4 mg/g). The MAGA incorporation significantly increased the uranium adsorption capacity (204.8 mg/g). Adsorption capacity of MAGA incorporated beads increased significantly with pH and then reached the maximum at pH 6.0. Consecutive adsorption and elution operations showed the feasibility of repeated use for p(HEMA-MAGA) chelating beads. (C) 2003 Elsevier B.V. All rights reserved.