Back
 ACES  Vol.5 No.1 , January 2015
Influence of Temperature and Water Vapour Pressure on Drying Kinetics and Colloidal Microstructure of Dried Sodium Water Glass
Abstract: Industrially produced sodium water glasses were dried in climates with controlled temperature and humidity to transparent amorphous water containing sodium silicate materials. The water glasses had molar SiO2:Na2O ratios of 2.2, 3.3 and 3.9 and were dried up to 84 days at temperatures between 40°C and 95°C and water vapour pressures between 5 and 40 kPa. The materials approached final water concentrations which are equilibrium values and are controlled by the water vapour pressure of the atmosphere and the microstructure of the solids. The microstructure of the dried water glasses was characterized by atomic force microscopy. It has a nanosized substructure built up by the silicate colloids of the educts but deformed by capillary forces. In the final drying equilibrium, the water vapour pressure of the atmosphere in the drying cabinet is equal to the reduced vapour pressure of the capillary system built up by the silicate colloids. Their size scale can be explained by the deformation of colloidal aggregates due to capillary forces.
Cite this paper: Roggendorf, H. , Fischer, M. , Roth, R. and Godehardt, R. (2015) Influence of Temperature and Water Vapour Pressure on Drying Kinetics and Colloidal Microstructure of Dried Sodium Water Glass. Advances in Chemical Engineering and Science, 5, 72-82. doi: 10.4236/aces.2015.51008.
References

[1]   Vail, J.G. (1952) Soluble Silicates—Their Properties and Uses, Vol. 1, Chemistry. Reinhold, New York.

[2]   Roggendorf, H., Grond, W. and Hurbanic, M. (1996) Structural Characterization of Concentrated Alkaline Silicate Solutions by 29Si-NMR Spectroscopy, FT-IR Spectroscopy, Light Scattering, and Electron Microscopy—Molecules, Colloids, and Dissolution Artefacts. Glass Sci. Technol., 69, 216-231.

[3]   Iler, R.K. (1979) The Chemistry of Silica. Solubility, Polymerisation, Colloid and Surface Properties, and Biochemistry. Wiley-Interscience Publication, New York.

[4]   Falcone, J.S. (2005) Silicon Compounds, Anthropogenic Silica and Silicates. In: Kirk-Othmer Encyclopedia of Chemical Technology, Wiley Online Library, New York.
http://dx.doi.org/10.1002/0471238961.1925142006011203.a01.pub2

[5]   Yoshida, A. (2006) Silica Nucleation, Polymerization, and Growth Preparation of Monodisprsed Sols. In: Bergna, H.E. and Roberts, W.O., Eds., Colloidal Silica: Fundamentals and Applications, Surfactant Science Series 131, 47-56.

[6]   Iler, R.K. (1982) Colloidal Components in Solutions of Sodium Silicate. In: Falcone, J.S., Ed., Soluble Silicates, ACS Symposium Series, 194, 95-114.

[7]   Healey, T. (2006) Stability of Aqueous Silica Sols. In: Bergna, H.E. and Roberts, W.O., Eds., Colloidal Silica: Fundamentals and Applications, Surfactant Science Series, 131, 247-252.

[8]   Bahlmann, E.K.F., Harris, R.K., Metcalfe, K., Rockliffe, J.W. and Smith, E.G. (1997) Silicon-29 NMR Self-Difusion and Chemical-Exchange Studies of Concentrated Sodium Silicate Solutions. Journal of the Chemical Society, Faraday Transactions, 93, 93-98.
http://dx.doi.org/10.1039/a604878a

[9]   Boschel, D., Janich, M. and Roggendorf, H. (2003) Size Distribution of Colloidal Silica in sodium Silicate Solutions Investigated by Dynamic Light Scattering and Viscosity Measurements. Journal of Colloid and Interface Science, 267, 360-368.
http://dx.doi.org/10.1016/j.jcis.2003.07.016

[10]   Nordstrom, J., Sundblom, A., Jensen, G.V., Pedersen, J.S., Palmqvist, A. and Matic, A. (2013) Silica/Alkali Ratio Dependence of the Microscopic Structure of Sodium Silicate Solutions. Journal of Colloid and Interface Science, 397, 9- 17.
http://dx.doi.org/10.1016/j.jcis.2013.01.048

[11]   Tognonvi, M.T., Massiot, D., Lecomte, A. and Rossignol, S. (2010) Identification of Solvated Species Present in Concentrated and Dilute Sodium Silicate Solutions by Combined 29Si NMR and SAXS Studies. Journal of Colloid and Interface Science, 352, 309-315.
http://dx.doi.org/10.1016/j.jcis.2010.09.018

[12]   Halasz, I., Li, R., Agarwal, M. and Miller, N. (2007) Monitoring the Structure of Water Soluble Silicates. Catalysis Today, 126, 196-202.
http://dx.doi.org/10.1016/j.cattod.2006.09.032

[13]   Trautz, V., Gartner, F., Korner, H.H., Linke, R., Weber, H. and Wirth, H. (1978) Fire-Protective Materials. Patent No. DE 2703022.

[14]   Dent Glasser, L.S. and Lee, C.K. (1973) Drying of Sodium Silicate Solutions. Journal of Applied Chemistry and Biotechnology, 21, 127-133.
http://dx.doi.org/10.1002/jctb.5020210502

[15]   Roggendorf, H. and Boschel, D. (2002) Hydrous Sodium Silicate Glasses Obtained by Drying Sodium Silicate Solutions. Journal of Glass Science and Technology, 75, 103-111.

[16]   Roggendorf, H., Boschel, D. and Trempler, J. (2001) Structural Evolution of Sodium Silicate Solutions Dried to Amorphous Solids. Journal of Non-Crystalline Solids, 293-295, 752-757.
http://dx.doi.org/10.1016/S0022-3093(01)00785-2

[17]   Pusey P.N. and Van Megen, W. (1990) The Glass Transition of Hard Spherical Colloids. Berichte der Bunsengesellschaft für physikalische Chemie, 94, 225-229.
http://dx.doi.org/10.1002/bbpc.19900940306

[18]   Cann, J.Y. and Cheek, D.L. (1925) Relationship between Composition and Boiling Point of Aqueous Solutions of Sodium Silicate. Industrial & Engineering Chemistry, 17, 512-514.
http://dx.doi.org/10.1021/ie50185a031

[19]   Brinker, C.J. and Scherer, G.W. (1990) Sol-Gel Science. Academic Press, San Diego.

[20]   Chiang, Y.-M., Birdie III, D.P. and Kingery, W.D. (1997) Physical Ceramics. John Wiley & Sons, New York.

[21]   Knudsen, M. (1909) Die Gesetze der Molekularstromung und der inneren Reibungsstromung der Gase durch Rohren. Annalen der Physik, 28, 75-130.
http://dx.doi.org/10.1002/andp.19093330106

[22]   Winston, P.W. and Bates, D.H. (1960) Saturated Solutions for the Control of Humidity in Biological Research. Ecology, 41, 232-237.
http://dx.doi.org/10.2307/1931961

[23]   Susan, D. (2005) Stereological Analysis of Spherical Particles: Experimental Assessment and Comparison to Laser Diffraction. Metall. Metallurgical and Materials Transactions A, 36, 2481-2492.
http://dx.doi.org/10.1007/s11661-005-0122-3

[24]   Vargaftik, N.B., Volkov, B.N. and Voljak, L.D. (1983) International Table of the Surface Tension of Water. Journal of Physical and Chemical Reference Data, 12, 817-820.
http://dx.doi.org/10.1063/1.555688

[25]   Weast, R.C., Ed. (1983) CRC Handbook of Chemistry and Physics. 62nd Edition, CRC Press, Boca Raton.

[26]   Muster, T.H., Prestidge, C.A. and Hayes, R.A. (2001) Water Adsorption Kinetics and Contact Angles of Silica Particles. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 176, 253-266.
http://dx.doi.org/10.1016/S0927-7757(00)00600-2

[27]   Washburn, E.W. (1921) The Dynamics of Capillary Flow. Physical Review, 17, 273-283.
http://dx.doi.org/10.1103/PhysRev.17.273

 
 
Top