Research Article

Spatially resolved Raman investigation on phase separations of mixed Na2SO4/MgSO4 droplets

  1. Jin-Ling Dong,
  2. Han-Shuang Xiao,
  3. Li-Jun Zhao,
  4. Yun-Hong Zhang*

Article first published online: 20 OCT 2008

DOI: 10.1002/jrs.2132

Issue

Journal of Raman Spectroscopy

Journal of Raman Spectroscopy

Volume 40, Issue 3, pages 338–343, March 2009

Additional Information

How to Cite

Dong, J.-L., Xiao, H.-S., Zhao, L.-J. and Zhang, Y.-H. (2009), Spatially resolved Raman investigation on phase separations of mixed Na2SO4/MgSO4 droplets. J. Raman Spectrosc., 40: 338–343. doi: 10.1002/jrs.2132

Author Information

  1. The Institute for Chemical Physics, Beijing Institute of Technology, Beijing, 100081 China

*The Institute for Chemical Physics, Beijing Institute of Technology, Beijing, 100081 China.

Publication History

  1. Issue published online: 6 MAR 2009
  2. Article first published online: 20 OCT 2008
  3. Manuscript Accepted: 28 AUG 2008
  4. Manuscript Received: 11 APR 2008

Funded by

  • NSFC. Grant Numbers: 20640420450, 20673010
  • China Postdoctoral Science Foundation. Grant Number: 20070410466
  • The Trans-Century Training Program Foundation for the Talents by the Ministry of Education of China

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Keywords:

  • spatially resolved Raman spectroscopy;
  • mixed Na2SO4/MgSO4 particles;
  • phase separation

Abstract

By using spatially resolved Raman spectroscopy together with in situ microscopy, mixed Na2SO4/MgSO4 aerosol particles with molar ratios of 1:1 and 2:1 deposited on a quartz substrate were carefully examined in their evaporation processes. Upon decreasing the relative humidity (RH), phase separations were found to occur for these droplets. For Na2SO4/MgSO4 droplets with a molar ratio of 1:1, two paths of phase separation were identified, and a large amount of small crystals were observed to disorderly distribute in the residual solutions. By comparisons with the known Raman spectra of crystals, it was concluded that the scattered crystals in the two paths were anhydrous Na2SO4 in metastable phase III and the double salt of Na2SO4· MgSO4 · 4H2O, respectively. For Na2SO4/MgSO4 aerosol droplets with a molar ratio of 2:1, only anhydrous Na2SO4 in metastable phase III precipitated with the decrease of RH. Copyright © 2008 John Wiley & Sons, Ltd.

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