Abstract: Al³⁺ modified silica gel adsorptive materials were prepared by treating ceramic fiber matrix with sequential impregnation of aqueous solution of sodium silicate(Na₂SiO₃),
acidic aluminium salt. The results show that the optimal reaction condition is 26.67% Na₂SiO₃, 10% aluminium salt and 1.8 solution pH value.
²⁹Si and²⁷AlMAS NMR spectra show that some Al is incorporated in SiO₄ tetrahedral framework structure which is not influenced by the
replacement of Al for Si atoms. The Al³⁺ modification results in symmetric stretching vibration shifting from 968cm^-1 of Si--OH to
954cm^-1 of Si (Al)--OH. SEM imagine reveals Al³⁺ modified silica gel is well scattered on the surface corrugated ceramic paper and in the
apertures between fibers of paper. EDS analysis indicates the existence and percentage of modified Al³⁺ in the adsorptive materials surface micro
zone. Porous medium surface area analysis shows that the mesopore is dominant for adsorption in Al³⁺ modified silica gel. For the Al³⁺
modification, the humidity adsorbing ability, heat resistance property and tensile strength and burst of Al³⁺ modified silica gel adsorptive
materials are superior to those of silica gel.

Key words: adsorption, Al³⁺ modified silica gel, heat resisting property, mechanical strength