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| Titel |
Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion |
| VerfasserIn |
S. J. Solomon, T. Custer, G. Schade, A. P. Soares Dias, J. Burrows |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 5, no. 10 ; Nr. 5, no. 10 (2005-10-24), S.2787-2796 |
| Datensatznummer |
250003109
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| Publikation (Nr.) |
 copernicus.org/acp-5-2787-2005.pdf |
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| Zusammenfassung |
| A novel atmospheric methanol measurement technique,
employing selective gas-phase catalytic conversion
of methanol to formaldehyde followed by detection
of the formaldehyde product, has been developed and
tested. The effects of temperature, gas flow rate, gas
composition, reactor-bed length, and reactor-bed
composition on the methanol conversion efficiency of a
molybdenum-rich, iron-molybdate catalyst [Mo-Fe-O] were
studied. Best results were achieved using
a 1:4 mixture (w/w) of the catalyst in quartz sand.
Optimal methanol to formaldehyde conversion
(>95% efficiency) occurred at a catalyst housing
temperature of 345°C and an estimated sample-air/catalyst
contact time of <0.2 seconds. Potential
interferences arising from conversion
of methane and a number of common volatile organic
compounds (VOC) to formaldehyde were found to
be negligible under most atmospheric conditions
and catalyst housing temperatures. Using the new
technique, atmospheric measurements of methanol were
made at the University of Bremen campus from
1 to 15 July 2004. Methanol mixing ratios ranged
from 1 to 5 ppb with distinct maxima at night.
Formaldehyde mixing ratios, obtained in
conjunction with methanol by periodically
bypassing the catalytic converter, ranged from
0.2 to 1.6 ppb with maxima during midday. These
results suggest that selective, catalytic
methanol to formaldehyde conversion, coupled with
existing formaldehyde measurement instrumentation,
is an inexpensive and effective means for
monitoring atmospheric methanol. |
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