Heterogeneous conversion of NO₂ on carbonaceous surfaces

Abstract

In the present study the heterogeneous conversion of NO₂ on commercial soot, freshly prepared flame soot and commercial soot treated with sulfuric acid has been investigated. The experimental results indicate a complex reaction mechanism in which the soot has to be treated as a reactant leading to deactivation of active sites on the surface with increasing NO₂ consumption. Mean uptake coefficients γ for the first few minutes of the reaction of ∽10^-6 have been determined for a consumption of ∽10¹³ NO₂ cm^-2. The γ-values decrease to <10^-8 for a consumption of ∽10¹⁵ NO₂ cm^-2, indicating that the influence of soot on the partitioning of NO_x in the atmosphere is negligible. Nitrous acid (HONO) and nitric oxide (NO) were found to be the major gas phase products. HONO yields up to 80% are observed, clearly showing that the nature of the reaction is non-catalytic. The humidity dependence of the reaction system was studied and indicates that water is necessary for HONO formation. In the reaction of pure HONO on soot surfaces, high yields of NO were observed, indicating a consecutive process: NO₂→HONO→NO. When soot was coated with sulfuric acid the yield of HONO decreased while that of NO increased. This behaviour is caused by an increasing reactivity of the intermediate HONO on the modified surface. The experimental results indicate that without any recycling mechanism HONO formation on soot surfaces is not of major importance in the atmosphere.

References

1. D. J. Lary, A. M. Lee, R. Toumi, M. J. Newchurch, M. Pirre and J. B. Renard, J. Geophys. Res., 1997, 102, 3671.
2. S. Bekki, J. Geophys. Res., 1997, 102, 10751.
3. K. Tabor, L. Gutzwiller and M. J. Rossi, J. Phys. Chem., 1994, 98, 6172.
4. M. Kalberer, K. Tabor, M. Ammann, Y. Parrat, E. Weingartner, D. Piguet, E. Rössler, D. T. Jost, A. Türler, H. W. Gäggeler and U. Baltensperger, J. Phys. Chem., 1996, 100, 15487.
5. C. A. Rogaski, D. M. Golden and L. R. Williams, Geophys. Res. Lett., 1997, 24, 381.
6. S. Kamm, O. Möhler, K.-H. Naumann, H. Saathoff and U. Schurath, in 1st Workshop of the EUROT RAC-2 Subproject Chemical Mechanism Development, ed. M. Ammann and R. Lorenzen, Report PSI Proceedings 97-02, ISSN 1019-6447, Zürich, 1997, p. 29.
7. M. Ammann, M. Kalberer, D. T. Jost, L. Tobler, E. Rössler, D. Piguet, H. W. Gäggeler and U. Baltensperger, Nature, 1998, 395, 157.
8. A. Gerecke, A. Thielmann, L. Gutzwiller and M. J. Rossi, Geophys. Res. Lett., 1998, 25, 2453.
9. C. A. Longfellow, A. R. Ravishankara and D. R. Hanson, J. Geophys. Res., 1999, 104, 13833.
10. M. S. Akhter, A. R. Chughtai and D. M. Smith, J. Phys. Chem., 1984, 88, 5334.
11. D. M. Smith, W. F. Welch, S. M. Graham, A. R. Chughtai, B. G. Wicke and K. A. Grady, Appl. Spectrosc., 1988, 42, 674.
12. L. A. Gundel, N. S. Guyot-Sionnest and T. Novakov, Aerosol Sci. Technol., 1989, 10, 343.
13. A. R. Chughtai, W. F. Welch, Jr., M. S. Akhter and D. M. Smith, Appl. Spectrosc., 1990, 44, 294.
14. F. DeSantis and I. Allegrini, Atmos. Environ., 1992, 26A, 3061.
15. K. Tabor, L. Gutzwiller and M. J. Rossi, Geophys. Res. Lett., 1993, 20, 1431.
16. J. C. Petit and J. Thlibi, in AERONOX—The Impact of No_x Emissions from Aircraft Upon the Atmosphere at Flight Altitudes 8–15 km, ed. U. Schumann, Report EUR 16209 EN, ISBN-92-826-8281-1, Brussels, 1995, p. 264.
17. D. M. Smith and A. R. Chughtai, Colloids Surfaces A: Physicochem. Eng. Aspects, 1995, 105, 47.
18. A. R. Chughtai, S. A. Gordon and D. M. Smith, Carbon, 1994, 32, 405.
19. R. M. Harrison, J. D. Peak and G. M. Collins, J. Geophys. Res., 1996, 101, 14429.
20. F. Sakamaki, S. Hatakeyama and H. Akimoto, Int. J. Chem. Kinet., 1983, 15, 1013.
21. J. N. Pitts, E. Sanhueza, R. Atkinson, W. P. L. Carter, A. M. Winter, G. W. Harris and C. N. Plum, Int. J. Chem. Kinet., 1984, 16, 919.
22. J. Kleffmann, K. H. Becker and P. Wiesen, Atmos. Environ., 1998, 32, 2721.
23. G. Lammel and J. N. Cape, Chem. Soc. Rev., 1996, 25, 361.
24. P. Wiesen, J. Kleffmann, R. Kurtenbach and K. H. Becker, Faraday Discuss., 1995, 100, 121.
25. J. Kleffmann, K. H. Becker and P. Wiesen, J. Chem. Soc., Faraday Trans., 1998, 94, 3289.
26. A. Febo, C. Perrino, M. Gherardi and R. Sparapani, Environ. Sci. Technol., 1995, 29, 2390.
27. K. H. Becker, J. Kleffmann, R. Kurtenbach and P. Wiesen, J. Phys. Chem., 1996, 100, 14984.
28. W. F. Cooke and J. J. N. Wilson, J. Geophys. Res., 1996, 101, 19395.
29. C. Liousse, J. E. Penner, C. Chuang, J. J. Walton, H. Eddleman and H. Cachier, J. Geophys. Res., 1996, 101, 19411.
30. T. Raunemaa, K. Kuuspalo, T. Ålander, A. Mirme and E. Tamm, J. Aerosol. Sci., 1996, 27, 455.
31. M. Ammann, U. Baltensperger, U. K. Bochert, B. Eichler, H. W. Gäggeler, D. T. Jost, A. Türler and A. P. Weber, J. Aerosol, Sci., 1995, 26, 61.
32. C. Kessler and U. Platt, in Physico-chemical Behaviour of Atmospheric Pollutants, ed. B. Versino and G. Angeletti, Reidel, Dordrecht, 1984, p. 412.
33. J. N. Pitts, H. Biermann, A. M. Winer and E. C. Tuazon, Atmos. Environ., 1984, 18, 847.
34. A. Sjödin and M. Ferm, Atmos. Environ., 1986, 20, 409.
35. D. Perner, C. Kessler and U. Platt, in Monitoring of Gaseous Pollutants by Tunable Diode Lasers, ed. R. Grisar, H. Preier, G. Schmidke and G. Restelli, Reidel, Dordrecht, 1987, p. 116.
36. Th. W. Kirchstetter, R. A. Harley and D. Littlejohn, Environ, Sci. Technol., 1996, 30, 2843.
37. M. Kalberer, M. Ammann, F. Arens, H. W. Gäggeler and U. Baltensperger, J. Geophys. Res., 1999, 104, 13825.
38. C. Alcala-Jornod, A. Gerecke and M. J. Rossi, in 2nd Workshop of the EUROT RAC-2 Subproject Chemical Mechanism Development, ed. U. Schurath and R. Roselieb, Karlsruhe, 1998, HEP2.