Elaine A. Faria

Aplicação e modificação química da sílica gel obtida de areia

The silica gel was obtained from sand and its surface was modified with POCl3 to produce Si-Cl bonds on the silica surface. Ethylenediamine was covalently bonded onto the chlorinated silica surface. The adsorption of the chlorides of divalent cobalt, nickel and copper was qualitatively studied to show that the bonding of ethylenediamine onto the silica gel surface produces a solid base capable of chelating metal ions from solution. The experiments illustrate the extraction of silica gel, its reactivity, the development of modified surfaces and its application in removing metal ions from water and are deigned for undergraduate inorganic chemistry laboratories.

Nanosized and reusable SiO2/ZrO2 catalyst for highly efficient biodiesel production by soybean transesterification

Nanosized SiO2/ZrO2 catalyst with high surface area (131.50 ± 14 m2 g-1) was prepared by the sol-gel method. The material presented highly homogeneous particles with an average diameter of 250 nm according to SEM images. It was applied in the transesterification of soybean oil for biodiesel production. The biodiesel conversion reached a yield of 96.2 ± 1.4 % after 3 h of transesterification reaction catalised by SiO2/ZrO2 (SiZr). The catalyst was recovered and reused six times, maintaining a catalytic efficiency of about 84.1 %.