Structural Evolution of Sol–Gel Derived Nanostructured Alumina Granules with Calcination Temperature

Abstract

Stable 2 M [mol/L] boehmite sol was prepared by modifying the Yoldas process, followed by a granulation process in which paraffin oil and ammonia solution were used as the media to facilitate shape forming and consolidation of the gel structure, respectively. The product granules were always spherical with large surface area and narrow pore size distribution. A systematic investigation of the effect of calcination temperature on the pore structures of the granules was carried out. When the calcination temperature was increased, the product granules exhibited larger pore size with reduced porosity. The pore structure can be precisely controlled by the calcination temperature.