Mesoporous alumina (I): Comparison of synthesis schemes using anionic, cationic, and non-ionic surfactants

Abstract

A series of mesoporous alumina was prepared using a selected group of anionic, non-ionic, and cationic surfactants with Al-tri- sec-butoxide or Al 3+ in organic solvent with stoichiometric amount of water, and in aqueous solution with different hydrolyzing agents, or with complexing agent at room temperature to 100 °C. A comparison of the physicochemical properties of the materials prepared was made with respect to surface area, thermal stability, and porosity. Anionic surfactants in aqueous solution produced thermally unstable materials but in organic solvent resulted in a moderately stable alumina phase. Both cationic and non-ionic surfactants produced thermally stable mesoporous alumina after removal of the surfactant upon calcination at 500 °C when the materials were synthesized in organic solvents. Overall, mesoporous alumina prepared with cationic cetyltrimethylammonium bromide in sec-butanol in the optimized substrate composition of Al:surfactant:H 2O:solvent = 1.0:0.3:2.0:15 exhibited the best textural property among the various synthesis systems investigated.