title: Adsorption of Cu and Mn on covalently cross-linked alginate gel beads.
abstract: The covalently cross-linked alginate gel beads were prepared by the reactions of Ca(2+)-doped alginate gel beads, which were formed by spraying a viscous alginate solution into a calcium chloride solution, with cyanogen bromide and following 1,6-diaminohexane. The cross-linking of alginate matrix decreased the mean bead diameter by about 30% and made the beads durable in some extent under alkaline conditions. The adsorption of metal ions on the covalently cross-linked alginate gel beads was rapid and reached at equilibrium within 30 min at 25 degrees C. Adsorption isotherms of Cu(II), Mn(II), and Ca2+ on the beads possessed a stepwise shape, which was firstly determined by Rorrer et al. [Ind. Eng. Chem. Res. 32 (1993) 2170] for cross-linked chitosan gel beads and explained by a pore-blockage mechanism. Higher selectivity was determined against Cu(II) over Mn(II) and Ca2+, especially at a low concentration region. These metal adsorption profiles for the covalently cross-linked alginate gel beads was almost the same as those for the un-cross-linked beads, indicating that the cross-linking reactions were performed without interfering the adsorption characteristics of alginate gel beads.
authors.affiliation: Department of Materials-Process Engineering and Applied Chemistry for Environments, Akita University, 1-1 Tegata Gakuen-Cho, Akita 010-8502, Japan. tgotoh@ac5.as.akita-u.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Gotoh
authors.forename: Keiei
authors.initials: K
authors.lastname: Matsushima
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Kikuchi
mesh_terms: D000327:Adsorption; D000464:Alginates / Q000737:chemistry*; D002122:Calcium Chloride; D003300:Copper / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003488:Cyanogen Bromide; D003959:Diamines; D020723:Glucuronic Acid / Q000737:chemistry*; D006603:Hexuronic Acids / Q000737:chemistry*; D007700:Kinetics; D008345:Manganese / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D018508:Water Purification / Q000379:methods*
chemical_list: D000464:Alginates; D003432:Cross-Linking Reagents; D003959:Diamines; D006603:Hexuronic Acids; D008345:Manganese; D003300:Copper; D020723:Glucuronic Acid; D002122:Calcium Chloride; D003488:Cyanogen Bromide; C007297:1,6-diaminohexane