Artigo
Physicochemical properties and morphology of spongolite from Mato Grosso do Sul (Brazil)
Fecha
2003-02-28Registro en:
Materials Chemistry and Physics. Lausanne: Elsevier B.V. Sa, v. 78, n. 3, p. 835-839, 2003.
0254-0584
10.1016/S0254-0584(02)00452-2
WOS:000179839900040
Autor
Universidade Federal de Mato Grosso do Sul (UFMS)
Universidade Estadual Paulista (Unesp)
Resumen
The physicochemical properties and morphology of spongolite, a fibrous hollow material from Mato Grosso do Sul State (Brazil) have been studied. The results of thermal analysis, scanning electron microscopy (SEM), X-ray diffraction and NMR spectroscopy indicated that external and internal surfaces of silica spicules are covered by silica gel layers. The water evolved in the range 120-350degreesC is the result of silanol groups condensation to siloxane bonds. Total homogenization of the needles is achieved by heating spongolite over 900degreesC. This mineral may be considered as a natural composite material containing surface-immobilized reactive species. The presence of active silica gel layers opens the possibilities of attaching functional groups to spongolite surface. (C) 2002 Elsevier B.V. B.V. All rights reserved.