Synthesis and structure study of ZnCo2O4 spinel prepared via coprecipitation process

ZnCo2O4 spinel was successfully prepared via co-precipitation process starting from corresponding metal chlorides in aqueous solutions at pH=13. Different calcination temperatures (400-500- 600-700-800-1000oC) and different Zn:Co molar ratios (1:2 - 1:2.5) were applied in an effort to prepare this important spinel with perfect specifications starting from cheap, easy to handle inorganic precursors and using a simple process. This process was chosen for its simple requirements and the ability to modify the resulting spinel characteristics by adjusting different parameters easily like mixing temperature, time and speed and the drying conditions. The resulting samples were characterized using x-ray powder diffraction (XRPD), Fourier transform Infra-Red spectroscopy (FT-IR), Differential thermal analysis (DTA). The coloration, crystallinity size, formation and decomposition of the resulting ZnCo2O4 were found to depend on the calcination temperatures, Zn:Co molar ratio and stirring time. Results showed that ZnCo2O4 spinel was formed at relatively low temperatures. All the samples shared a cubic structure with Fd3m space group.

Conditions of separating acetone from aqueous sodium chloride solutions and the nature of hydrolysed molecules and ions

The method of separation of acetone from its solutions by the ‘Salting out’ effect was studied. This was interpreted by association of water molecules to the salt ions formed so decreasing the number of free water molecules because of the formation of a new liquid phase the solubility of organic compound in which is less than in water. Separation of acetone, can be explained qualitatively but not quantitatively. Its mechanism and the molecular and ionic constructions can not be fully understood by salting out alone. In order to achieve better explanation, the thermal and concentrations conditions of acetone separation were determined. Results have shown that separation takes place, when a second turbid pronounce phase was taken place by heating the mixture to a certain temperature. A complete separation occurs when reaching some higher temperatures. The state of the hydrolysed molecules of both salt and acetone was shown quantitatively.