Preparation and Performance of Novel Al~(3+) Modified Silica Gel Adsorptive Materials

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 Al 3+ 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.