Metal chelating properties of Cibacron Blue F3GA-derived poly(EGDMA-HEMA) microbeads

Metal chelating properties of Cibacron Blue F3GA-derived poly(EGDMA-HEMA) m icrobeads have been studied. Poly(EGDMA-HEMA) microbeads were prepared by s uspension copolymerization of ethylene glycol dimethacrylate (EGDMA) and hy droxy-ethyl methacrylate (HEMA) by using poly(vinyl alcohol), benzoyl perox ide, and toluene as the stabilizer, the initiator, and the pore-former, res pectively. Cibacron Blue F3GA was covalently attached to the microbeads via the nucleophilic substitution reaction between the chloride of its triazin e ring and the hydroxyl groups of the HEMA, under alkaline conditions. Micr obeads (150-200 mu m in diameter) with a swelling ratio of 55%, and carryin g 16.5 mu mol Cibacron Blue F3GA/g polymer were used in the adsorption/deso rption studies. Adsorption capacity of the microbeads for the selected meta l ions, i.e., Cu(II), Zn(II), Cd(II), Fe(III), and PB(II) were investigated in aqueous media containing different amounts of these ions (5-200 ppm) an d at different pH values (2.0-7.0). The maximum adsorptions of metal ions o nto the Cibacron Blue F3GA-derived microbeads were 0.19 mmol/g for Cu(II), 0.34 mmol/g for Zn(II), 0.40 mmol/g for Cd(II), 0.91 mmol/g for Fe(III), an d 1.05 mmol/g for Pb(II). Desorption of metal ions were studied by using 0. 1 M HNO3. High desorption ratios (up to 97%) were observed in all cases. Re peated adsorption/desorption operations showed the feasibility of repeated use of this novel sorbent system. (C) 1999 John Wiley & Sons, Inc.