Preparation of the precursor of porous alumina particles using immobilized urease in alginate gel templates

Abstract

This paper describes a new method to precipitate the precursor of porous alumina particles by using a porous organic matrix as the template and an enzyme as the precipitant supplier. In this work, the precursor of alumina was precipitated in urease-containing aiginate gel spheres dispersed in aqueous solutions containing urea and A13+ ion. Urease was used to hydrolyze urea so that the precursor of alumina, basic aluminum sulfate, may be precipitated selectively within the gel spheres. By burning off the gel matrices after the precipitation of the precursor, porous alumina particles were obtained. The resultant alumina particles about 1 to 2 mm in diameter had sharp pore size distribution profiles around 0.1 to 0.01 μm. The inside of the alumina particles was able to be made either hollow or filled, depending on the aging time after the precipitation of the precursor.