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www.atmos-chem-phys-discuss.net/6/1481/2006/
doi:10.5194/acpd-6-1481-2006
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under a Creative Commons License.
Characterization of iodine particles with Volatilization-Humidification Tandem Differential Mobility Analyser (VH-TDMA), Raman and SEM techniques
1International Laboratory for Air Quality and Health, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001, Australia
2Spectroscopic Group, Department of Chemistry, University of Oslo, P.O.Box 1033 Blindern, 0315 Oslo, Norway
3Analytical EM Facility, School of Physical & Chemical Sciences; Queensland University of Technology, Australia
Abstract. Particles formed upon photo-oxidation of CH2I2 and particles of I2O5 and HIO3 have been studied using a Volatilisation and Humidification Tandem Differential Mobility Analyser (VH-TDMA) system. Volatilization and hygroscopic behaviour have been investigated as function of temperature (from 25 to 400°C), humidity (RH from 80 to 98%), initial aerosol sizes (from 27 to 100 nm mobility diameter) and in nitrogen or air as the sheath gasses. The volatility behaviour of particles formed upon photo-oxidation of CH2I2 is more similar to that of HIO3 particles in a filtered sheath air than in nitrogen, with the particle shrinkage occurring at 190°C and accompanied by hygroscopic growth. Despite its high solubility, HIO3 was found not to be hygroscopic at room temperature with no significant growth displayed until the thermodenuder temperature reached 200°C or above when the particles have transformed into I2O5. Diiodopentaoxide (I2O5) particles exhibit relatively low hygroscopic growth factors of 1.2–2 in the humidity range investigated. Scanning Electron Microscopy (SEM) of particles formed upon photo-oxidation of CH2I2 shows that their primary elemental components were iodine and oxygen in a stoichiometric ratio of approximately 1:2 with 10% error. Both Raman spectra and SEM show poor crystallinity for all the aerosols produced.
Discussion Paper (PDF, 688 KB) Interactive Discussion (Closed, 3 Comments) Publication in ACP not foreseen
Citation: Ristovski, Z. D., Fletcher, C., D’Anna, B., Johnson, G. R., and Bostrom, J. T.: Characterization of iodine particles with Volatilization-Humidification Tandem Differential Mobility Analyser (VH-TDMA), Raman and SEM techniques, Atmos. Chem. Phys. Discuss., 6, 1481-1508, doi:10.5194/acpd-6-1481-2006, 2006. Bibtex EndNote Reference Manager XML
