Influence of calcination parameters on the properties of alumina as a catalyst support

Authors

1 Department of Chemical Engineering, Iran University of Science and Technology, Tehran, P.O. Box 16765163, Iran.

2 National Petrochemical Company, Petrochemical Research and Technology Company, Tehran, P.O. Box 1435884711, Iran.

Abstract

The preparation history of Al2O3 strongly determines its properties for the application as a catalyst support. The interaction of calcination heating rate and temperature and its influence on the structural, textural, and acidic properties of alumina were studied. Commercial-alumina was calcined at 800C, 900C, 1000C, 1050C, 1100C, and 1150C by 2.5C/min, 5C/min, and 10C/min. By increasing temperature up to 1050C, transition aluminas (, , and ) were reported, but the heating rate accelerated phase transformation and changed the amount of each phase in the samples. At 1100C and 1150C, -alumina appeared. Mesopore alumina with di erent surface areas (265-126 m2/g) was synthesized at calcination temperature from 800C to 1050C; when temperature reached 1100C, the surface area decreased drastically and was around 14 m2/g. Interaction of heating rate on the temperature had minimal e ect on the surface area of samples, but considerable e ect on the acidic properties. The intensity of acidic properties was a ected by heating rate with nonlinear pro les. By increasing the heating rate, the ratio of Al cations occupied tetrahedral per octahedral sites and defect of crystal structures increased, so the surface acidity of aluminas was increased.

Keywords

Scientia Iranica
Volume 23, Issue 3 - Serial Number 3
Transactions on Chemistry and Chemical Engineering (C)
June 2016
Pages 1128-1135

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