Document Detail


A counter-current parallel-plate membrane denuder for the non-specific removal of trace gases.
MedLine Citation:
PMID:  16955907     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In this paper we present a counter-current parallel-plate membrane diffusion denuder for the non-specific removal of trace gases from an air flow. In this design, gaseous pollutants are removed by diffusing from a sample channel to two purge channels by crossing microporous membranes. In the laboratory, at a sample flow rate of 5 L/min and purge flow rates of 5 L/min each, gas removal efficiencies ranged from 84% for CO to 72% for SF6. Removal efficiencies increased with lower sample flow rate, a higher sample to purge flow rate ratio, a longer channel length, and using molecules with higher diffusion coefficient. Removal efficiencies were, however, not affected by the sample channel height. In addition, gas penetration was exponentially associated with the product of channel length, diffusion coefficient, and the inverse of sample flow rate. Particle losses were significant (10-25% losses) only for particles smaller than 50 nm. In a field evaluation, the denuder's performance was tested with an aerosol produced in a photochemical chamber. The denuder's performance was similar to that observed in the laboratory and was stable over time. Finally, the denuder was tested with a semivolatile organic aerosol. Particle mass losses due to volatilization were about 30%.
Authors:
Pablo A Ruiz; Joy E Lawrence; Stephen T Ferguson; Jack M Wolfson; Petros Koutrakis
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Environmental science & technology     Volume:  40     ISSN:  0013-936X     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2006 Aug 
Date Detail:
Created Date:  2006-09-06     Completed Date:  2007-01-16     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  5058-63     Citation Subset:  IM    
Affiliation:
Exposure, Epidemiology and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts 02215, USA. pruiz@hsph.harvard.edu
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MeSH Terms
Descriptor/Qualifier:
Aerosols / analysis*
Air Movements
Air Pollutants / analysis*
Diffusion
Environmental Monitoring / instrumentation,  methods*
Equipment Design
Filtration / methods*
Models, Chemical
Organic Chemicals / chemistry
Particle Size
Volatilization
Chemical
Reg. No./Substance:
0/Aerosols; 0/Air Pollutants; 0/Organic Chemicals

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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