Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (11): 2521-2527.doi: 10.3866/PKU.WHXB20111121


High Temporal and Spatial Resolution Measurements of the Rapid Efflorescence of Sea Salt Droplets

TONG Hai-Jie1, QIAN Zheng-Gang1, REID Jonathan P.2, ZHANG Yun-Hong1   

  1. 1. Institute of Chemical Physics, Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, P. R. China;
    2. School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
  • Received:2011-06-02 Revised:2011-08-31 Published:2011-10-27
  • Contact: ZHANGYun-Hong
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20933001, 20873006).

Abstract: The rapid efflorescence of individual seawater droplets on polytetrafluoroethylene (PTFE, hydrophobic) and quartz (hydrophilic) substrates was investigated using a high-speed camera for imaging and micro-Raman spectroscopy to spatially resolve the particle composition. The morphology of the evaporating sea salt particles was captured using millisecond time resolution and micrometer spatial resolution. Upon rapid desiccation with dry N2 on a quartz substrate, Na2Ca5(SO4)6·3H2O and Na2xCa6-x(SO4)6· 3H2O (0<x<1) crystallized first followed by NaCl and finally KMgCl3·6H2O. We determined the formation behavior of the mixed sodium-calcium salts as crystallization products during the quick desiccation process and CaSO4·2H2O during the slow desiccation process. In addition, the crystallization location of different crystal products were identified and the growth speed of Na2Ca5(SO4)6·3H2O crystal was compared with that of CaSO4·2H2O crystal. Moreover, sea salt particles with a hollow structure were observed on the PTFE substrate at the end of the quick efflorescence process.

Key words: Sea salt, High-speed photography, Raman spectroscopy, Efflorescence, Relative humidity


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