Alumina

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Effect of Surface Acidity and Basicity of Aluminas on ‎Asphaltene Adsorption and Oxidation

Journal Title, Volume, Page: 
J Colloid Interface Sci., 360(1):233-8
Year of Publication: 
2011
Authors: 
Nashaat N. Nassar
Department of Chemical & Petroleum Engineering, Alberta Ingenuity Centre for In-Situ Energy, University of Calgary, Calgary, Alberta, Canada
Current Affiliation: 
Department of Chemical Engineering, Faculty of Engineering and Information Technology, An-Najah National University, Nablus, Palestine
Azfar Hassan
Department of Chemical & Petroleum Engineering, Alberta Ingenuity Centre for In-Situ Energy, University of Calgary, Calgary, Alberta, Canada
Pedro Pereira-Almao
Department of Chemical & Petroleum Engineering, Alberta Ingenuity Centre for In-Situ Energy, University of Calgary, Calgary, Alberta, Canada
Preferred Abstract (Original): 

This study investigates the effect of surface acidity and basicity of aluminas on asphaltene adsorption followed by air oxidation. Equilibrium batch adsorption experiments were conducted at 25 °C with solutions of asphaltenes in toluene at concentrations ranging from 100 to 3000 g/L using three conventional alumina adsorbents with different surface acidity. Data were found to better fit to the Freundlich isotherm model showing a multilayer adsorption. Results showed that asphaltene adsorption is strongly affected by the surface acidity, and the adsorption capacities of asphaltenes onto the three aluminas followed the order acidic > basic and neutral. Asphaltenes adsorbed over aluminas were subjected to oxidation in air up to 600 °C in a thermogravimetric analyzer to study the catalytic effect of aluminas with different surface acidity. A correlation was found between Freundlich affinity constant (1/n) and the catalytic activity. Basic alumina that has the lowest 1/n value, depicting strongest interactions, has the highest catalytic activity, followed by neutral and acidic aluminas, respectively.

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