Alumina is widely used as a sorbent and catalyst support. These applications typically require high surface area, stability in the used environment and often the presence of specific groups on the surface. Many of these goals can be achieved by the synthesis of alumina aerogels with specific modifying agents added to the alumina precursor before gelation. In this work we studied how the gel modification with organic and inorganic acids, and beta-diketones affects the textural and adsorption properties of nanocrystalline alumina synthesized by the modified aerogel procedure. The highest specific surface areas obtained exceeded 1000 m2/g, being 4-5 times higher than those of typically used alumina materials. The activity of high surface area nanocrystalline alumina materials in dehydrochlorination of (2-chloroethyl)ethyl sulfide (2-CEES) and 1-chlorobutane compared favorably with that of other nanocrystalline metal oxides. The temperature of 1-chlorobutane decomposition could be decreased by ca. 100°C in comparison with MgO aerogel extensively studied earlier while maintaining 98% selectivity to butenes. Sulfated alumina aerogels had high surface areas ca. 600 m2/g after calcination at 600°C and showed excellent acidic properties typical for sulfated alumina. Overall, the developed nanoparticulate modified alumina aerogels appear to have excellent adsorption properties with enhanced stability and reactivity.
Journal: TechConnect Briefs
Volume: 1, Nanotechnology 2010: Advanced Materials, CNTs, Particles, Films and Composites
Published: June 21, 2010
Pages: 364 - 367
Industry sector: Advanced Materials & Manufacturing
Topics: Nanoparticle Synthesis & Applications