Development of a Knudsen Cell Reactor for Measuring the Uptake of Atmospheric Gases on Particulate Matter

Heterogeneous reactions between mineral dust aerosols and gas phase volatile organic compounds have the potential to impact important atmospheric chemical processes. However, little is known about the uptake and reactivity of volatile organic compounds on particulates found in the environment. A Knudsen cell was designed and constructed for providing precise measurement of reaction probabilities within these systems. The instrument was validated through a series of experiments. After validating the Knudsen cell against several key benchmarks, the instrument was used to measure the uptake coefficient for ethanol on particulate silicon dioxide. The uptake coefficient of ethanol on silicon dioxide, a common compound in mineral dust aerosols, was determined to be 7 x 10-7. Therefore, uptake of ethanol on silicon dioxide would be competitive with the loss of other volatile organic compounds on silicon dioxide, which show similar rates of uptake. The Knudsen cell was validated and measured the uptake of ethanol on silicon dioxide, and future work with the Knudsen cell will study the uptake of chemical warfare agent simulants on metal oxides.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Chemistry

Department dc:contributor.department

Chemistry

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2011

Author dc:creator

• Rockhold, Thomas Hall Jr.

Chair dc:contributor.committeechair

• Morris, John R.

Committee members dc:contributor.committeemember

• Tanko, James M.
• Long, Gary L.

• Uptake Coefficient
• Volatile Organic Compounds
• Ethanol
• Knudsen Cell
• Silicon Dioxide
• Mineral Dust Aerosols

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-05042011-163554

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/32194