Surface Sites and Unrelaxed Surface Energies of Tetrahedral Silica Polymorphs and Silicate

Details

• Personal Author:
  Demchuk, Eugene ; Murashov VV
• Description:
  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. [Description provided by NIOSH]
• Subjects:
  Aluminum Silicates Dust Occupational Health Safety Silicon Dioxide
• Keywords:
  Models Quantitative-analysis Respirable-dust Silica-dusts Silicates Silicosis Surface-properties Thermodynamics
• ISSN:
  0039-6028
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  6-19
• Volume:
  595
• Issue:
  1
• NIOSHTIC Number:
  nn:20028938
• Citation:
  Surf Sci 2005 Dec; 595(1-3):6-19
• Email:
  vmurashov@cdc.gov
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7) ; Silica (CAS RN 7631-86-9)
• Federal Fiscal Year:
  2006
• Peer Reviewed:
  True
• Source Full Name:
  Surface Science
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:0735ac5fb7117b53cbd703443fe271095f5485312882170fa3708ac3b081fda320c1659619d43803b15ca2566471f666e9c16df3fb8f43d514f39d2f58c15210
• Download URL:
  https://stacks.cdc.gov/view/cdc/190026/cdc_190026_DS1.pdf
• File Type:
  [PDF - 1.87 MB ]