scholarly journals Combined surface and gas phase diffusion through plugs of porous adsorbent in transition diffusion region.

1981 ◽  
Vol 14 (1) ◽  
pp. 13-19 ◽  
Author(s):  
MASASHI ASAEDA ◽  
JIRO WATANABE ◽  
YASUSHI MATONO ◽  
KOJI KOJIMA ◽  
RYOZO TOEI
Keyword(s):  
Gas Phase ◽  
Diffusion Region ◽  
Phase Diffusion ◽  
Porous Adsorbent

What is effective ΔPO2 in a gas-phase diffusion system?

1981 ◽  
Vol 45 (1) ◽  
pp. 9-11 ◽  
Author(s):  
C.V. Paganelli ◽  
A. Ar ◽  
H. Rahn
Keyword(s):  
Gas Phase ◽  
Diffusion System ◽  
Phase Diffusion

Numerical analysis of gas-phase diffusion resistance in a droplet train apparatus

2002 ◽  
Vol 362 (1-2) ◽  
pp. 56-62 ◽  
Author(s):  
Masakazu Sugiyama ◽  
Seiichiro Koda ◽  
Akihiro Morita
Keyword(s):  
Numerical Analysis ◽  
Gas Phase ◽  
Diffusion Resistance ◽  
Phase Diffusion

NEW METHOD FOR PREDICTION OF BINARY GAS-PHASE DIFFUSION COEFFICIENTS

1966 ◽  
Vol 58 (5) ◽  
pp. 18-27 ◽  
Author(s):  
Edward N. Fuller ◽  
Paul D. Schettler ◽  
J. Calvin. Giddings
Keyword(s):  
Gas Phase ◽  
Diffusion Coefficients ◽  
New Method ◽  
Phase Diffusion

scholarly journals Technical note: Determination of binary gas-phase diffusion coefficients of unstable and adsorbing atmospheric trace gases at low temperature – arrested flow and twin tube method

2020 ◽  
Vol 20 (6) ◽  
pp. 3669-3682 ◽  
Author(s):  
Stefan Langenberg ◽  
Torsten Carstens ◽  
Dirk Hupperich ◽  
Silke Schweighoefer ◽  
Ulrich Schurath
Keyword(s):  
Gas Phase ◽  
Diffusion Coefficients ◽  
Trace Gases ◽  
Heterogeneous Reactions ◽  
Viscosity Data ◽  
Atmospheric Conditions ◽  
Binary Diffusion ◽  
Phase Diffusion ◽  
Flow Method ◽  
Binary Diffusion Coefficients

Abstract. Gas-phase diffusion is the first step for all heterogeneous reactions under atmospheric conditions. Knowledge of binary diffusion coefficients is important for the interpretation of laboratory studies regarding heterogeneous trace gas uptake and reactions. Only for stable, nonreactive and nonpolar gases do well-established models for the estimation of diffusion coefficients from viscosity data exist. Therefore, we have used two complementary methods for the measurement of binary diffusion coefficients in the temperature range of 200 to 300 K: the arrested flow method is best suited for unstable gases, and the twin tube method is best suited for stable but adsorbing trace gases. Both methods were validated by the measurement of the diffusion coefficients of methane and ethane in helium and air as well as nitric oxide in helium. Using the arrested flow method the diffusion coefficients of ozone in air, dinitrogen pentoxide and chlorine nitrate in helium, and nitrogen were measured. The twin tube method was used for the measurement of the diffusion coefficient of nitrogen dioxide and dinitrogen tetroxide in helium and nitrogen.

scholarly journals Diffusion of volatile organics through porous snow: impact of surface adsorption and grain boundaries

2013 ◽  
Vol 13 (14) ◽  
pp. 6727-6739 ◽  
Author(s):  
T. Bartels-Rausch ◽  
S. N. Wren ◽  
S. Schreiber ◽  
F. Riche ◽  
M. Schneebeli ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Gas Phase ◽  
Trace Gases ◽  
Snow Sample ◽  
Volatile Organics ◽  
Thin Sections ◽  
Phase Diffusion ◽  
Surface Snow ◽  
Partitioning Coefficients ◽  
Diffusion Profiles

Abstract. Release of trace gases from surface snow on earth drives atmospheric chemistry, especially in the polar regions. The gas-phase diffusion of methanol and of acetone through the interstitial air of snow was investigated in a well-controlled laboratory study in the temperature range of 223 to 263 K. The aim of this study was to evaluate how the structure of the snowpack, the interaction of the trace gases with the snow surface, and the grain boundaries influence the diffusion on timescales up to 1 h. The diffusive loss of these two volatile organics into packed snow samples was measured using a chemical ionization mass spectrometer. The structure of the snow was analysed by means of X-ray-computed micro-tomography. The observed diffusion profiles could be well described based on gas-phase diffusion and the known structure of the snow sample at temperatures ≥ 253 K. At colder temperatures, surface interactions start to dominate the diffusive transport. Parameterizing these interactions in terms of adsorption to the solid ice surface, i.e. using temperature-dependent air–ice partitioning coefficients, better described the observed diffusion profiles than the use of air–liquid partitioning coefficients. No changes in the diffusive fluxes were observed by increasing the number of grain boundaries in the snow sample by a factor of 7, indicating that for these volatile organic trace gases, uptake into grain boundaries does not play a role on the timescale of diffusion through porous surface snow. For this, a snow sample with an artificially high amount of ice grains was produced and the grain boundary surface measured using thin sections. In conclusion, we have shown that the diffusivity can be predicted when the structure of the snowpack and the partitioning of the trace gas to solid ice is known.

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