Abstract

VILAR, Rossana B. C.; JESUS, Alexandre de; BENVENUTTI, Edilson V.  and  SILVA, Márcia M.. Silica chemically modified with p-anisidine, p-phenytidine and p-phenylenediamine groups used as adsorbent for Pb²⁺, Cu²⁺, Cd²⁺ and Ni²⁺ in aqueous and ethanol solutions. Quím. Nova [online]. 2008, vol.31, n.2, pp. 285-289. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422008000200018.

Silica gel was chemically modified with the aromatic amines p-anisidine, p-phenytidine and p-phenylenediamine, using grafting reactions. The resulting modified silicas were characterized by infrared spectroscopy and N₂ adsorption/desorption isotherms. The organic groups were covalently immobilized in a monolayer form. These modified silicas were investigated as adsorbents for Pb²⁺, Cu²⁺, Cd²⁺ and Ni²⁺ in aqueous and ethanol solutions. In a general way, the adsorption capacity values for all adsorbents presented the following sequence: Pb²⁺ >> Cu²⁺ @Cd²⁺ @ Ni²⁺. Adsorption studies for all adsorbents, in competitive medium, showed better selectivity for Cu²⁺ and Pb²⁺ in aqueous medium and for Pb²⁺ in ethanol solution. Desorption studies were carried out using HCl and HNO₃ as eluents.

Keywords : organofunctionalized silica; adsorption; metals.