Specific surface area and structures of aluminas from fibrillar pseudoboehmite

AUTOR(ES)

Vieira Coelho, A.C., Rocha, G.A., Souza Santos, P., Souza Santos, H., Kiyohara, P.K.

FONTE

Matéria (Rio de Janeiro)

DATA DE PUBLICAÇÃO

2008-06

RESUMO

By heating powders of the aluminum monohydroxide fibrillar pseudoboehmite from 200ºC to 1400ºC several high surface area aluminas are prepared and characterized by X-ray diffraction and electron optical methods. Aqueous sols with pseudoboehmite fibrils of different lengths were dried by two methods: at room temperature and spray-dried. The following aluminas were obtained after treatment of the powders at increasing temperatures and having a range of specific surface areas: γ-Al2O3 (470ºC - 770ºC; 179 m²/g - 497 m²/g); δ -Al2O3 (770ºC - 930ºC; 156 m²/g - 230 m²/g); θ-Al2O3 (930ºC - 1050ºC; 11 m²/g - 200 m²/g); α-Al2O3 (1050ºC - 1400ºC; 2 m²/g - 17 m²/g). Spray-dried powders, fired at the same temperature than the ground powders, showed higher specific surface areas. The higher surface area alumina have values of the same order of magnitude of the commercial "ad-cat" aluminas.

Documentos Relacionados

• Structure, surface area and morphology of aluminas from thermal decomposition of Al(OH)(CH3COO)2 crystals
• Alumina specific area, morphology and structure obtained from some precursors.
• Shape insensitive optimal adhesion of nanoscale fibrillar structures
• Structural properties of fibrillar proteins isolated from the cell surface and cytoplasm of Streptococcus salivarius (K+) cells and nonadhesive mutants.
• Area intercondylaris tibiae: Osseous surface structure and its relation to soft tissue structures and applications to radiography.