Sorption Study of Water Vapour on Thermally Treated Nesquehonite (MgCo3.3H2O) at 450 and 5500C.

F. A. Shebl

Ain Shams University, Faculty of Science, Department of Chemistry, Abbasi Cairo, Egypt.

ABSTRACT:

The sorption of water vapour by magnesium oxide; obtained by thermal decomposition of' nesqu ebonite at 450° and 550°C; results peculiar adsorption isotherms that do not belong to any of the BDDT isotherms classification, nor to stepwise isotherms. The water retained after outgassing for 50 hours at 450° and 550oC did not change and were found equal to the stoichiometric water needed to-react with the magnesium oxide forming magnesium hydroxide. Complete phase change of magnesium oxide to the hydroxide was proved by X-ray diffraction patterns, The obtained adsorption isotnerms are divided into four regiocs. The first region limited up to P/Po = 0.105 which mostly belong to Henry's law while the second region at P/P0 = 0.105 is almost vertical step independent on the pressure at which Mg (OH)2 is directly and partly obtained. The third region is similar to type I adsorption isotherm, Indicating the predominance of microporous structure of mixture of magnesium oxide and the formed magnesium hydroxide. However, the fourth region is related to the adsorption isorption isotherm of the formed magnesium hydroxide only. Mechanestic behaviour of water uptake at these regions are also discussed.

KEYWORDS:

Sorption; Nesquehonite

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Copy the following to cite this article: Shebl F. A. Sorption Study of Water Vapour on Thermally Treated Nesquehonite (MgCo3.3H2O) at 450 and 5500C.. Orient J Chem 1988;4(1).

Copy the following to cite this URL: Shebl F. A. Sorption Study of Water Vapour on Thermally Treated Nesquehonite (MgCo3.3H2O) at 450 and 5500C.. Orient J Chem 1988;4(1). Available from: http://www.orientjchem.org/?p=41875