Influence of processing medium on retention of specific surface area of gamma-alumina at elevated temperature

The effects of suspending medium of water and ethanol on retention of surface area of gamma-alumina at elevated temperature were studied, The study was conducted with particular interest in the commonly used impregnation technique for stabilization of gamma-alumina. The ethanol medium of processing was compared with the more commonly employed water medium of processing while impregnating gamma-alumina for surface modification. Lanthanum and tin precursors were taken to impregnate gamma-alumina using both ethanol and water medium. Ethanol treatment retained higher surface area and increased the alpha-alumina transformation temperature. The pore size distribution of both samples showed an apparent difference and that impregnated in ethanol had larger pore size than that in water. This suggests fewer particle-to-particle contacts resulting from the improved thermal stability due to impregnation in ethanol. Evolution of finer micro-pores is observed only in the case of the ethanol-processed alumina after heat treatment at elevated temperature. (C) 2001 Elsevier Science B.V. All rights reserved.