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

• Autor(a) principal: Souza, Elton J. [UNESP]
• Data de Publicação: 2011
• Outros Autores: 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]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.2478/v10026-011-0045-2; http://hdl.handle.net/11449/10148
• topic: 2,2-Bipyridine; silica gel; adsorption; metal ions

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.