Chemical tailoring of porous aluminum oxide xerogels

In the present work a new low-cost sol-gel method has been developed to prepare highly porous alumina systems. The prime consideration of this research work was to avoid the complicated and laborious preparation technique and the expensive drying processes. Aluminum oxide hydroxide gel systems were synthesized by a new sol-gel route. The sol-gel process starts from only two chemical compounds; from an aluminum salt and a solvent, and it does not adopt any basic agent or complex formation. All gel systems were dried at atmospheric pressure to obtain xerogels. Different chemical agents (such as gelation agent propylene oxide, surfactant characteristic citric acid and ethyl acetate or basic agent carbamide and urotropine) were applied. Their application was varied in the steps of the sol-gel procedure. Some wet gels were subjected to different treatments (microwave radiation and freezing in vacuum) before the drying process. The cryogels evolved by lyophilization was provided for the comparison. The route of propylene oxide' addition to system reacted for 24 h produces a bead-like structure with the highest porosity and smallest pores in the present work.