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Evaluation of Pollution Uptake on Consolidated Limestone Mary F. Striegel NCPTT
Air Pollution Sulfur dioxide Nitrogen dioxide Pesticides Volcanoes <ul><li>Erosion of stone profiles </li></ul><ul><li>Los...
Limestone and Marble Limestone Sedimentary rock  Calcium Carbonate fossils Marble Metamorphic rock
Acid Rain and Buildings <ul><li>Chemical weathering- Acidic dissolution of the carbonate minerals  </li></ul><ul><li>Calci...
What are Stone Strengtheners / Consolidants ? <ul><li>Pollutants interact with stone, hastening deterioration and loss of ...
Protection of Calcerous Stones <ul><li>Film forming sealers  (drying oils, waxes, plant resins) </li></ul><ul><li>Acrylics...
The Ideal stone Strengthener <ul><li>Strengthen the stone </li></ul><ul><li>Protect against moisture and Pollution </li></...
Issues to Consider <ul><li>Application techniques </li></ul><ul><li>Compatibility with substrate </li></ul><ul><li>Durabil...
Research focus <ul><li>Evaluate the success of 4 different stone strengtheners </li></ul>Trade Name Chemical Family Eponex...
Chemical Structures ?
Methods Initial analysis <ul><li>Laser Profilometry </li></ul><ul><li>Colorimetry </li></ul><ul><li>Fourier Transform Infr...
(a) Laser Profilometry Methods <ul><li>Using a laser a surface profile </li></ul><ul><li>Measurement of each stone </li></...
Methods <ul><li>Record color change of stone  samples </li></ul><ul><li>Determine magnitude of color change at various int...
<ul><li>( c)  Fourier Transform Infrared Spectroscopy </li></ul>Methods <ul><li>Molecules absorb infrared energy at certai...
Methods Extract solution at column start Running column with eluent creating the  separation Testing / separation of ionic...
Methods (e) Application of Treatments Dipping Spraying Ace polyethylene  sprayer
Methods (f) Environmental Chamber Exposure <ul><li>Must provide stable, reproducible, controllable conditions </li></ul><u...
OH 100 Before Treatment OH 100 After Treatment Roughness of the core (Sk) =20 µm  Roughness of valleys (Svk) =29 µm  Void ...
HCT spray  Before HCT spray  After Roughness of the core (Sk) =22 µm  Roughness of valleys (Svk) =27.1 µm  Void volume of ...
Results Ion Chromatography Sulfate ions
Results SO 2  Deposition Velocities Deposition velocity = V d  = flux / [SO 2 ] = 1 / r  total = 1 / r a  + r b  + r c <ul...
Results
Results Treatment Deposition Velocity (cm/s) STDeV HCT DiP 2.45 0.19 OH100 0.01 0.05 Eponex 1510 0.05 0.03 Untreated 0.27 ...
Ongoing Research <ul><li>Hydrophilicity  </li></ul><ul><li>Chemical change on treated stone </li></ul><ul><li>SEM Image fr...
Acknowledgements <ul><li>National Park Service </li></ul><ul><li>NCPTT </li></ul><ul><li>MRP Staff </li></ul><ul><li>NSU <...
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Effects Of Pollution On Treated Limestone Rough Draft

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This is a rough draft presentation originally given by Dr. Catherine Situma to the NSU research day. It forms the basis of my presentation to be given at the DOI Conference on the Environment.

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Transcript of "Effects Of Pollution On Treated Limestone Rough Draft"

  1. 1. Evaluation of Pollution Uptake on Consolidated Limestone Mary F. Striegel NCPTT
  2. 2. Air Pollution Sulfur dioxide Nitrogen dioxide Pesticides Volcanoes <ul><li>Erosion of stone profiles </li></ul><ul><li>Loss of polish </li></ul><ul><li>Progressive illegibility of inscriptions </li></ul><ul><li>Dramatic disintegration </li></ul>Pollution: An integral part of weathering
  3. 3. Limestone and Marble Limestone Sedimentary rock Calcium Carbonate fossils Marble Metamorphic rock
  4. 4. Acid Rain and Buildings <ul><li>Chemical weathering- Acidic dissolution of the carbonate minerals </li></ul><ul><li>Calcite -calcium carbonate </li></ul><ul><li>Dolomite- calcium magnesium carbonate </li></ul>
  5. 5. What are Stone Strengtheners / Consolidants ? <ul><li>Pollutants interact with stone, hastening deterioration and loss of surface integrity </li></ul><ul><li>Consolidants can be added to increase strength and protect remaining binder </li></ul><ul><li>A chemical that holds old decaying </li></ul><ul><li>stone together </li></ul><ul><li>Irreversible </li></ul><ul><li>A method of last resort </li></ul>
  6. 6. Protection of Calcerous Stones <ul><li>Film forming sealers (drying oils, waxes, plant resins) </li></ul><ul><li>Acrylics </li></ul><ul><li>Epoxies </li></ul><ul><li>Stearates </li></ul><ul><li>Silicones </li></ul><ul><li>Fluoropolymers </li></ul><ul><li>Others (fluorosilicates, fluorides, barium hydroxides, oxalates, lime watering) </li></ul>Entrapment of moisture Clouding /discoloration Inability to remain attached to carbonate materials
  7. 7. The Ideal stone Strengthener <ul><li>Strengthen the stone </li></ul><ul><li>Protect against moisture and Pollution </li></ul><ul><li>Health / safety and impact on the environment </li></ul>
  8. 8. Issues to Consider <ul><li>Application techniques </li></ul><ul><li>Compatibility with substrate </li></ul><ul><li>Durability of treatment </li></ul><ul><li>Performance / strengthening value </li></ul><ul><li>Depth of Penetration </li></ul><ul><li>Effect on appearance </li></ul><ul><li>Effect on porosity and permeability </li></ul>
  9. 9. Research focus <ul><li>Evaluate the success of 4 different stone strengtheners </li></ul>Trade Name Chemical Family Eponex 1510 Hydrogenated bisphenol A-epichlohydrin based epoxy resin Acryloid B-72 Acrylic copolymer OH 100 Alkoxysilane HCT Hydroxylating Conversion Treatment
  10. 10. Chemical Structures ?
  11. 11. Methods Initial analysis <ul><li>Laser Profilometry </li></ul><ul><li>Colorimetry </li></ul><ul><li>Fourier Transform Infrared Spectroscopy (FTIR) </li></ul>Consolidate / Treatment Environmental Chamber <ul><li>Ion Chromatography </li></ul><ul><li>Colorimetry </li></ul><ul><li>FTIR </li></ul>
  12. 12. (a) Laser Profilometry Methods <ul><li>Using a laser a surface profile </li></ul><ul><li>Measurement of each stone </li></ul><ul><li>is taken </li></ul><ul><li>Examples of parameters: Roughness, void volumes, ratio of texture aspects, flatness of distribution </li></ul>
  13. 13. Methods <ul><li>Record color change of stone samples </li></ul><ul><li>Determine magnitude of color change at various intervals throughout experiment </li></ul><ul><li>Observation of any color change as a result of the treatment </li></ul><ul><li>Track the aging of the treatment </li></ul>(b) Colorimetry
  14. 14. <ul><li>( c) Fourier Transform Infrared Spectroscopy </li></ul>Methods <ul><li>Molecules absorb infrared energy at certain frequencies dependent on the types of bonds present </li></ul><ul><li>Spectra or graph produced is a fingerprint for the molecules on the surface of the stone </li></ul>
  15. 15. Methods Extract solution at column start Running column with eluent creating the separation Testing / separation of ionic species into columns based on the speed by which they travel through a liquid eluent <ul><li>Examples: chloride, bromide, sulfate, </li></ul><ul><li>Phosphate, nitrate and weak </li></ul><ul><li>organic acids </li></ul>(d) Ion Chromatography
  16. 16. Methods (e) Application of Treatments Dipping Spraying Ace polyethylene sprayer
  17. 17. Methods (f) Environmental Chamber Exposure <ul><li>Must provide stable, reproducible, controllable conditions </li></ul><ul><li>Temperature typically 25 ºC </li></ul><ul><li>Humidity typically 75% RH ) </li></ul><ul><li>Wind speed typically 40 dm/sec ) </li></ul><ul><li>SO 2 exposure dosage typically 50 ppb </li></ul><ul><li>Record reliable data for each, every 3seconds for 10 days </li></ul>
  18. 18. OH 100 Before Treatment OH 100 After Treatment Roughness of the core (Sk) =20 µm Roughness of valleys (Svk) =29 µm Void volume of valleys (vvv) =0.00612 µm 3 / µm 2 Roughness of the core (Sk) =17.7 µm Roughness of valleys (Svk) =31 µm Void volume of valleys (vvv) =0.0071 µm 3 / µm 2 <ul><li>Porosity (dominant factor) </li></ul><ul><li>Surface roughness (deep valleys correlate directly with increasing velocity) </li></ul>Results
  19. 19. HCT spray Before HCT spray After Roughness of the core (Sk) =22 µm Roughness of valleys (Svk) =27.1 µm Void volume of valleys (vvv) Vvv =0.00998 Roughness of the core (Sk) =18.3 µm Roughness of valleys (Svk) =29.2 µm Void volume of valleys (vvv) =0.00636 µm 3 / µm 2 Results
  20. 20. Results Ion Chromatography Sulfate ions
  21. 21. Results SO 2 Deposition Velocities Deposition velocity = V d = flux / [SO 2 ] = 1 / r total = 1 / r a + r b + r c <ul><li>Surface resistance (r c ) of materials can be determined if the aerodynamic and boundary layer Resistance (r a +r b ) to gas transfer is known </li></ul>SO2 Stone Water film r a –aerodynamic resistance r b -boundary layer resistance r c water + r c stone (Surface resistance)
  22. 22. Results
  23. 23. Results Treatment Deposition Velocity (cm/s) STDeV HCT DiP 2.45 0.19 OH100 0.01 0.05 Eponex 1510 0.05 0.03 Untreated 0.27 0.06 HCT spray 1.72 0.15 Acryloid B-72 0.04 0.16
  24. 24. Ongoing Research <ul><li>Hydrophilicity </li></ul><ul><li>Chemical change on treated stone </li></ul><ul><li>SEM Image from the Weiss research Group </li></ul><ul><li>Attenuated Total Reflection (ATR) FTIR spectroscopy to study the chemical nature of treated stones. </li></ul>
  25. 25. Acknowledgements <ul><li>National Park Service </li></ul><ul><li>NCPTT </li></ul><ul><li>MRP Staff </li></ul><ul><li>NSU </li></ul>
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