Influenceof aluminium precursor on physico-chemical properties of aluminium hydroxidesand oxides Part II. Al(ClO4)3·9H2O |
| |
Authors: | Barbara Pacewska Olga Kluk-Płoskońska D. Szychowski |
| |
Affiliation: | (1) Faculty of Building Engineering, Mechanics and Petrochemistry, Institute of Chemistry , Warsaw University of Technology, Płock, Poland, 09-400, Łukasiewicza 17 St. |
| |
Abstract: | Aluminium hydroxide was precipitated during a hydrolysis of aluminium perchlorate in ammonia medium. The materials were studied with the following methods: thermal analysis, IR spectroscopy, X-ray diffraction, low-temperature nitrogen adsorption and adsorption–desorption of benzene vapours. Freshly precipitated boehmite had a high value of SBET=211 m2 g–1 determined from nitrogen adsorption, good sorption capacity for benzene vapours, developed mesoporous structure and hydrophobic character. After prolonged refluxing at elevated temperature its crystallinity increased which was accompanied by an increase of specific surface determined from nitrogen adsorption up to 262m2g–1 , decrease of sorption capacity for benzene vapours and stronger hydrophobic character. The calcinations of all boehmites at temperature up to 1200°C resulted in formation of à-Al2O3 via transition form of γ-, δ- and θ-Al2O3. The samples of aluminium oxides obtained after calcination at 550 and 900°C were characterised with high values of specific surface area of 205–220 and 138–153 m2 g–1 , respectively. The SBET values calculated for the oxide samples derived from aged hydroxides and calcined at 1200°C are higher than for the analogous sample prepared without the ageing step. It was concluded that the process of ageing at elevated temperature developed thermal stability of aluminium oxides. |
| |
Keywords: | anion boehmite metastable aluminium oxides thermal decomposition |
本文献已被 SpringerLink 等数据库收录! |
|