Thermal Analysis of the Modified, Coated and Bonded Alumina Surfaces

Egyptian Petroleum Research Institute, Nasr City, Cairo, Egypt. Chemistry department, Faculty of Science, Taif University, KSA. _________________________________________________________________________________________ Nine alumina samples of various modification techniques were subjected to thermal analysis via thermogravimetric analysis (TGA) and differential thermal analysis (DTA), in order to estimate their applicability as solid stationary phases or solid support in gas chromatography. The modifications of alumina sorbents performed in this investigation single or multi-treatments includes: Calcination, hydrothermal treatment, alkali metal treatment, coating with polyethylene glycol, and bonding with polyethylene glycol. These modifications to obtain different deactivation degrees of alumina surfaces to covet most separation problems. The modified alumina samples are more thermally stable compared with parent and coated alumina. The parent alumina exhibits an exothermic peak around 500 C which may indicate a phase change corresponding to the transition from pseudo-boehmite into γ-Al2O3.Modification, any of the modification methods applied is associated with a pronounced increase in the thermal stability compared with parent alumina. This study is important reflecting the degree of application of alumina surfaces in many fields depending on the thermal stability of these compounds. __________________________________________________________________________________________