Graduation Year

2005

Document Type

Thesis

Degree

M.S.Ch.E.

Degree Granting Department

Chemical Engineering

Major Professor

Aydin Sunol, Ph.D., P.E.

Co-Major Professor

John Wolan, Ph.D.

Committee Member

Sermin Sunol, Ph.D.

Keywords

Sol-gel, Aging, Extraction and drying, Impregnation, Calcination, Functionalization, Porosity, Surface area

Abstract

The strength, thermal stability, pore structure and morphology are keys to success for wider deployment of aerogels. Furthermore, co or subsequent functionalization of the surfaces are equally, if not more important. This study addresses these issues through a new method. The path involves successful use of surfactant templating, supercritical extraction and drying, and supercritical fluid aided functionalization of the surface. Alumina support and alumina supported nickel catalyst particles are used to evaluate the approach. Initially thermally stable surfactant alumina was synthesized. The surfactant template was removed completely with the aid of a supercritical solvent mixture. Surfactant-templated alumina aerogel showed remarkable thermal stability and gave specific surface area above 500m2 /g both before and after calcination. The alumina support is subsequently impregnated with nickel. BET and BJH method (Nitrogen adsorption-desorption isotherms) were used to follow the removal of solvents and templates as well as tracking the textural properties for the synthesized gel. Meanwhile, co-precipitated nickel oxide/alumina system was also synthesized for comparison with the supercritical impregnation nickel oxide/alumina system. SEM-EDS and XPS were employed to study the distribution of the nickel on the alumina support and the percentage was compared with the initial mixture of the sol gels.

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