caa a22 4500 477061435 CHVBK 20180405111401.0 cr unu---uuuuu 170330e19961101xx s 000 0 eng 10.1007/BF00053794 doi (NATIONALLICENCE)springer-10.1007/BF00053794 The heterogeneous formation of N2O over bulk condensed phases in the presence of SO2 at high humidities [Elektronische Daten] [M. Pires, H. Van den Bergh, M. Rossi] In view of the uncertainty of the origin of the secular increase of N2O, we studied heterogeneous processes that contribute to formation of N2O in an environment that comes as close as possible to exhaust conditions containing NO and SO2, among other constituents. The N2O formation was followed using electron capture gas chromatography (ECD-GC). The other reactants and intermediates (SO2, NO, NO2 and HONO) were monitored using gas phase UV-VIS absorption spectroscopy. Experiments were conducted at 298 and 368 K as well as at dry and high humidity (approaching 100% rh) conditions. There is a significant heterogeneous rate of N 2 O formation at conditions that mimic an exhaust plume from combustion processes.The simultaneous presence of NO, SO2, O2 in the gas phase and condensed phase water, either in the bulk liquid or adsorbed state has been confirmed to be necessary for the production of significant levels of N2O. The stoichiometry of the overall reaction is: 2 NO+SO2+H2O → N2O+H2SO4. The maximum rate of N2O formation occurred at the beginning of the reaction and scales with the surface area of the condensed phase and is independent of its volume. A significant rate of N2O formation at 368 K at 100% rh was also observed in the absence of a bulk substrate. The diffusion of both gas and liquid phase reactants is not rate limiting as the reaction kenetics is dominated by the rate ofN2O formation under the experimental conditions used in this work. The simultaneous presence of high humidity (90-100% rh at 368 K) and bulk condensed phase results in the maximum rate and final yield of N2O approaching 60% and 100% conversion after one hour in the presence of amorphous carbon and fly-ash, respectively. Kluwer Academic Publishers, 1996 N2O formation nationallicence heterogeneous reactions nationallicence synthetic exhaust/flue gas nationallicence soot nationallicence fly-ash nationallicence calcite nationallicence sulfuric acid solutions nationallicence high relative humidities nationallicence Pires M. Laboratoire de Pollution Atmosphérique et Sol (LPAS), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland aut Van den Bergh H. Laboratoire de Pollution Atmosphérique et Sol (LPAS), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland aut Rossi M. Laboratoire de Pollution Atmosphérique et Sol (LPAS), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland aut Journal of Atmospheric Chemistry Kluwer Academic Publishers; http://www.wkap.nl 25/3(1996-11-01), 229-250 0167-7764 25:3<229 1996 25 10874 https://doi.org/10.1007/BF00053794 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00053794 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pires M. Laboratoire de Pollution Atmosphérique et Sol (LPAS), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland aut NATIONALLICENCE 700 1- Van den Bergh H. Laboratoire de Pollution Atmosphérique et Sol (LPAS), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland aut NATIONALLICENCE 700 1- Rossi M. Laboratoire de Pollution Atmosphérique et Sol (LPAS), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland aut NATIONALLICENCE 773 0- Journal of Atmospheric Chemistry Kluwer Academic Publishers; http://www.wkap.nl/ 25/3(1996-11-01), 229-250 0167-7764 25:3<229 1996 25 10874 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer