Attachment of 2,2-bipyridine onto a silica gel for application as a sequestering agent for copper, cadmium and lead ions from an aqueous medium
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Data
2011-01-01
Autores
Souza, Elton J. [UNESP]
Cristante, Valtair M. [UNESP]
Padilha, Pedro M. [UNESP]
Jorge, Sonia M. A. [UNESP]
Martines, Marco A. U.
Silva, Rafael I. V. [UNESP]
Carmo, Devaney R. [UNESP]
Castro, Gustavo R. [UNESP]
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Resumo
A method was developed to attach 2,2-bipyridine (BP) onto a silica gel surface by a two-step reaction. The first step consisted of a reaction between the matrix and a silylating agent, 3-chloropropyltrimeth-oxysilane. In the second step of the reaction, a ligand molecule was attached onto Si-CPTS, yielding the product Si-BP. The modified material contained 0.431 +/- 0.01 mmol of 2,2-bipyridine per gram of modified silica, as confirmed by FT-IR spectra of the proposed structure. The surface modification was characterized by the BET technique, which revealed a decrease in the surface area from 614 to 450 m(2) g(-1). The series of adsorption isotherms for the metal ions were adjusted to fit a modified Langmuir equation. The maximum number of moles of copper, cadmium and lead ions adsorbed was 0.64, 0.53, and 0.54 mmol g-1, respectively. The surface saturation was calculated as phi fraction and the values obtained, Cu(II) = 1.160, Cd(II) = 1.044 and Pb(II) = 0.997, suggest a type 1:1 metal-ligand complex.
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2,2-Bipyridine, silica gel, adsorption, metal ions
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Polish Journal of Chemical Technology. Warsaw: Versita, v. 13, n. 4, p. 28-33, 2011.