Sílica quimicamente modificada com os grupos p-anisidina, p-fenitidina e p-fenilenodiamina usada como adsorvente para Pb2+, Cu2+, Cd2+ e Ni2+ em soluções aquosa e etanólica

Abstract

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+ ≫ Cu 2+ ≅ Cd2+ ≅ Ni2+. Adsorption studies for all adsorbents, in competitive medium, showed better selectivity for Cu 2+ and Pb2+ in aqueous medium and for Pb2+ in ethanol solution. Desorption studies were carried out using HCl and HNO 3 as eluents.