Abstract
Abstract. The well established technique of gas chromatography is used to investigate interactions of sulfur dioxide with a crystalline ice film in a fused silica wide bore column. Peak shape analysis of SO2 chromatograms measured in the temperature range 205–265 K is applied to extract parameters describing a combination of three processes: (i) physisorption of SO2 at the surface, (ii) dissociative reaction with water and (iii) slow uptake into bulk ice. Process (ii) is described by a dissociative Langmuir isotherm. The pertinent monolayer saturation capacity is found to increase with temperature. The impact of process (iii) on SO2 peak retention time is found to be negligible under our experimental conditions.By analyzing binary chromatograms of hydrophobic n-hexane and hydrophilic acetone, the premelt surface layer is investigated in the temperature range 221–263 K, possibly giving rise to irregular adsorption. Both temperature dependencies fit simple van't Hoff equations as expected for process (i), implying that irregular adsorption of acetone is negligible in the investigated temperature range. Adsorption enthalpies of −45 ± 5 and −23±2 kJ mol−1 are obtained for acetone and n-hexane.The motivation of our study was to assess the vertical displacement of SO2 and acetone in the wake of aircraft by adsorption on ice particles and their subsequent sedimentation. Our results suggest that this transport mechanism is negligible.
Highlights
Adsorption of SO2 on ice surfaces is of interest in the chemistry and physics of the troposphere and stratosphere
For low concentrations the retention times of SO2 are strongly dependent on the amount of SO2 injected
The most simplistic model for adsorption is Henry’s adsorption isotherm: the surface concentration q as a function of the gas partial pressure p is given by q = KHp
Summary
Adsorption of SO2 on ice surfaces is of interest in the chemistry and physics of the troposphere and stratosphere. Large ice particles in contrails have been shown by lidar soundings to settle fairly rapidly (Schumann, 1994). This gave rise to speculations that sedimentation of ice particles provides a significant mechanism for the vertical displacement of SO2 and possibly other adsorbing trace gases, in the upper troposphere. Huthwelker et al (2006) and Crowley et al (2010) found that the results of Langenberg were in disagreement with the work of Clegg and Abbatt (2001) and other investigators: in contrast to these studies, Langenberg’s analysis implied a classical temperature dependence, i.e., more SO2 being adsorbed at lower temperatures. The experimental results and their reanalysis are published in the peer-reviewed literature for the first time
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
