Role of the Knudsen layer in the theory of heterogeneous reactions and in flows with surface reactions

1974 ◽  
Vol 6 (6) ◽  
pp. 913-920 ◽  
Author(s):  
M. N. Kogan ◽  
N. K. Makashev
Keyword(s):  
Surface Reactions ◽  
Knudsen Layer ◽  
Heterogeneous Reactions

On the role of heterogeneous reactions in aluminum combustion

2016 ◽  
Vol 168 ◽  
pp. 378-392 ◽  
Author(s):  
Julien Glorian ◽  
Stany Gallier ◽  
Laurent Catoire
Keyword(s):  
Heterogeneous Reactions ◽  
Aluminum Combustion

scholarly journals The significant contribution of HONO to secondary pollutants during a severe winter pollution event in southern China

2019 ◽  
Vol 19 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Xiao Fu ◽  
Tao Wang ◽  
Li Zhang ◽  
Qinyi Li ◽  
Zhe Wang ◽  
...  
Keyword(s):  
Southern China ◽  
Heterogeneous Reactions ◽  
Severe Winter ◽  
Peak Enhancement ◽  
Key Species ◽  
Secondary Pollutants ◽  
Light Effects ◽  
Haze Formation ◽  
The Pearl River

Abstract. Nitrous acid (HONO) can strongly affect atmospheric photochemistry in polluted regions through the production of hydroxyl radicals (OHs). In January 2017, a severe pollution episode occurred in the Pearl River Delta (PRD) of China, with maximum hourly PM2.5, ozone, and HONO levels reaching 400 µg m−3, 150 ppb, and 8 ppb, respectively, at a suburban site. The present study investigated the sources and processes generating such high HONO concentrations and the role of HONO chemistry in this severe winter episode. Four recently reported HONO sources were added to the Community Multiscale Air Quality (CMAQ) model, including RH-dependent (relative humidity) and light-enhancing effects on heterogeneous reactions, photolysis of particulate nitrate in the atmosphere, and photolysis of HNO3 and nitrate on surfaces. The revised model reproduced the observed HONO and significantly improved its performance for O3 and PM2.5. The model simulations showed that the heterogeneous generation on surfaces (with RH and light effects) was the largest contributor (72 %) to the predicted HONO concentrations, with the RH-enhancing effects more significant at nighttime and the light-enhancing effects more important in the daytime. The photolysis of total nitrate in the atmosphere and deposited on surfaces was the dominant HONO source during noon and afternoon, contributing above 50 % of the simulated HONO. The HONO photolysis was the dominant contributor to HOx production in this episode. With all HONO sources, the daytime average O3 at the Heshan site was increased by 24 ppb (or 70 %), compared to the simulation results without any HONO sources. Moreover, the simulated mean concentrations of TNO3 (HNO3+ fine particle NO3-) at the Heshan site, which was the key species for this haze formation, increased by about 17 µg m−3 (67 %) due to the HONO chemistry, and the peak enhancement reached 55 µg m−3. This study highlights the key role of HONO chemistry in the formation of winter haze in a subtropical environment.

scholarly journals The Role of Oxygen and Surface Reactions in the Deposition of Silicon Oxide like Films from HMDSO at Atmospheric Pressure

2012 ◽  
Vol 9 (11-12) ◽  
pp. 1116-1124 ◽  
Author(s):  
Rüdiger Reuter ◽  
Katja Rügner ◽  
Dirk Ellerweg ◽  
Teresa de los Arcos ◽  
Achim von Keudell ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Silicon Oxide ◽  
Surface Reactions

On the kinetics of the Langmuir-type heterogeneous reactions

2011 ◽  
Vol 16 (4) ◽  
pp. 467-476 ◽  
Author(s):  
Vladas Skakauskas ◽  
Pranas Katauskis
Keyword(s):  
Steady State ◽  
Surface Coverage ◽  
Surface Reactions ◽  
Heterogeneous Reactions ◽  
The Other ◽  
Two Dimensional ◽  
Finite Difference Technique ◽  
Planar Surfaces ◽  
Adsorption Desorption ◽  
Kinetics Of

In this paper we investigate three two-dimensional in space mathematical models of the kinetics of unimolecular heterogeneous reactions proceeding onto planar surfaces. All models include the diffusion of the reactant from a bounded vessel towards an adsorbent, adsorption of the molecules of the reactant, their desorption, conversion (reaction) of the adsorbate into a product, instantaneous product desorption, and the diffusion of the product from the adsorbent into the same vessel. One of these models is based on the Langmuir-type kinetics of the surface reactions, the other one is based on the local steady-state value of the surface coverage, and the last one, in addition to the first model, involves the diffusion of the adsorbate along the adsorbent. Diffusivity of all species is assumed to be constant. Models were solved numerically by using the finite difference technique. By changing input parameters the effects of the rate constants of the reactant adsorption, desorption, and reaction and the influence of the surface diffusion of the adsorbate and approximation of the surface coverage by its steady-state value on the kinetics of surface reactions were studied numerically.

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