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Surface sites and unrelaxed surface energies of tetrahedral silica polymorphs and silicate.

Authors
Murashov-VV; Demchuk-E
Source
Surf Sci 2005 Dec; 595(1-3):6-19
NIOSHTIC No.
20028938
Abstract
Surface properties of respirable silica, which represents a major occupational safety concern, were investigated computationally, and a model for quantitative characterization of crystalline silica surface sites was developed. It was found that the surface energy of crystalline solids, such as silica and silicates, can be calculated as a product of the surface site density and site energy. The energies of sites formed by faceting tetrahedral silica polymorphs and aluminosilicate were determined by parametric fitting ab initio surface energies to site densities. Boltzmann's statistics was used to describe the distribution of faces as an exponential function of unrelaxed surface energy in the comminuted crystalline solids. Using these findings, crystallographic face distributions on fractured quartz, coesite, tridymite, and cristobalite were derived and average silanol hydroxyl densities in fractured particulate of these materials were estimated as 0.070, 0.059, 0.058, and 0.055 A-2, respectively. The proposed method of quantitative characterization of the surface bridges the gap between microscopic simulations and measurable observables, such as cytotoxicity of respirable silica.
Keywords
Silica-dusts; Silicates; Silicosis; Surface-properties; Respirable-dust; Models; Quantitative-analysis; Thermodynamics
CODEN
SUSCAS
CAS No.
7631-86-9; 14808-60-7
Publication Date
20051205
Document Type
Journal Article
Email Address
vmurashov@cdc.gov
Fiscal Year
2006
NTIS Accession No.
NTIS Price
Issue of Publication
1-3
ISSN
0039-6028
NIOSH Division
HELD
Source Name
Surface Science
State
WV
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