Development of a Knudsen Cell Reactor for Measuring the Uptake of Atmospheric Gases on Particulate Matter
Abstract
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.
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- Masters Theses [19660]