Published online by Cambridge University Press: 21 February 2011
Microporous alumino-silicate gels were prepared by the sol-gel method. TheAl cations were incorporated into these systems by mixing an aluminumnitrate solution into silica water based sols under controlled pHconditions. The micro structure as well as the form of the products areinfluenced by the amount of Al additives. Al cations have significanteffects on the properties of silica sols and gels. The alumino-silicate gelhas micro porosity with surface area as high as 300 m2/g evenafter calcining at 900 °C for one hour. Strong negative charge is found onthese alumino-silicate surfaces in aqueous solution indicating the Alcations have been substituted isomorphically into the Si sites in theframework of silica.