title: Supramolecular structures on silica surfaces and their adsorptive properties.
abstract: The study of adsorptive and chemical immobilization of beta-cyclodextrin on a surface of hydroxylated silicas with various porous structure is described. Using IR spectroscopy, thermal gravimetrical analysis with a programmed heating, and chemical analysis of the silica surface, it is shown that the process of adsorption-desorption of beta-cyclodextrin depends on the porous structure of the silica. The reaction of esterification was used for chemical grafting of beta-cyclodextrin on the surface of hydroxylated silicas. Hydrolytic stability of silicas chemically modified by beta-cyclodextrin apparently is explained by simultaneous formation of chemical and hydrogen bonds between surface silanol groups and hydroxyl groups of beta-cyclodextrin. The uptake of the cations Cu(II), Cd(II), and Pb(II) and the anions Cr(VI) and As(V) by silicas modified with beta-cyclodextrin is investigated as a function of equilibrium ion concentrations. The increase of ion uptake and selectivity of ion extraction in comparison with starting silicas is established. It is due to the formation of surface inclusion complexes of the "host-guest" type in which one molecule of beta-cyclodextrin interacts simultaneously with several ions.
authors.affiliation: V. Vernadsky Institute of General and Inorganic Chemistry, National Academy of Sciences of Ukraine, Akademika Palladina prospect 32-34, Kiev 03680, Ukraine.
authors.forename: Vladimir N
authors.initials: VN
authors.lastname: Belyakov
authors.forename: Lyudmila A
authors.initials: LA
authors.lastname: Belyakova
authors.forename: Anatoly M
authors.initials: AM
authors.lastname: Varvarin
authors.forename: Olexandra V
authors.initials: OV
authors.lastname: Khora
authors.forename: Sergei L
authors.initials: SL
authors.lastname: Vasilyuk
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Kazdobin
authors.forename: Tetyana V
authors.initials: TV
authors.lastname: Maltseva
authors.forename: Alexey G
authors.initials: AG
authors.lastname: Kotvitskyy
authors.forename: Angela F
authors.initials: AF
authors.lastname: Danil de Namor