Tag Archives: Thermal Analysis

Detection Of Certain Spices Subjected To Gamma Irradiation By Using Thermal Analysis Technique (Review Completed - Accepted)

The present investigation was carried out to apply a detection method of some irradiated spices using thermal analysis technique. Black pepper, cumin and ginger were irradiated using γ- irradiation at dose levels 5, 10 and 15 kGy, and stored for 12 months at room temperature. Thermal analysis techniques TGA and DTA were studied for characterizing irradiated spices. Thermo gravimetric analysis (TGA) is a method where the measurement of mass as a function of heating is recorded. TGA was used to determine the moisture and ash contents and thermal stabilities. Nonsignificant changes of the weight loss percent due to the irradiation occurred on the studied spices up to 10 kGy . The weight loss decreased at the first step up to 100 oC due to the release of water of hydration. Another sharp decreasing in weight loss percent at the second step 220- 300 oC may be due to volatilization of the sample. The final weight loss weight loss stage up to 500 oC may be due to burn out the fixed carbon remaining in the sample. As the irradiation dose increased from control up to 15 kGy, the weight loss percent at the dehydration step increased.

The kinetics of the spices decomposition were studied in order to ascertain the type of weight loss mechanism and calculate the activation energy Ea .

The differential thermal analysis DTA of the studied samples showed two main characteristic peaks, endothermic one due to the dehydration process and the second peak may be due to the partial volatilization of the aromatic compounds of the main constituent of the studied spices. Finally, it could be recommended that using γ- irradiation (up to 10.0 kGy) for black pepper, cumin and ginger are thermally stable to human consumption.

 

Keywords: Activation energy, DTA, Gamma irradiated spices, TGA, Thermal Analysis

Study of the Catalytic and Surface Characteristics of Nickel Based Catalyst Supported With Metal Oxide for H/D Isotopic Exchange (Published)

Nickel catalysts supported with different metal oxides proved to be suitable for H/D isotopic exchange between hydrogen and water vapor. Ferric and aluminum oxide, proved to be suitable as promoter for nickel catalyst for such reaction Cr2O3, CoO and MnO were selected to be the second promoter for nickel catalyst in addition to Fe2O3 producing ternary catalytic systems. Accordingly, Ni/Fe2O3/AL2O3, Ni/Fe2O3/CoO and Ni/Fe2O3/MnO ternary catalytic systems were prepared by the Coprecipitation technique. These systems were characterized through complexometric titration, IR absorption spectroscopy, thermal analysis and x-ray analysis. The catalytic activity of the examined systems was carried out using a simple test reaction. The kinetic and thermodynamic parameters of the prepared systems were calculated and discussed followed by study the surface nature of these catalysts which characterized through specific surface area measurements, pore volume and pore radius analysis. It was concluded that not only the preparation method, but also the type of the support and its amount in the catalyst mixture are important factors which affect the surface quality of the catalyst.

Keywords: Complexomtric Analysis, IR Spectra, Specific Catalytic Activities, Surface Catalyst Nature, Thermal Analysis, X-Ray Analysis