WASHING OF MULTICOMPONENT GELS PRIOR TO DRYING

The sol-gel route is attractive for the preparation of multicomponent gels because homogenization on an atomic level might be possible. Prio r to the drying of the wet gels it is sometimes an advantage to wash o r rinse the gel using different types of solvents, i.e., for the prepa ration of aerogels. In this work we have studied the effect on composi tion of washing cordierite gels prepared using two different routes in four different solvents. Magnesium and aluminum were leached from the wet gels during washing in especially ethanol and acetone and the com position of the gel was severely altered relative to cordierite. The a mount of magnesium and aluminum removed from the gels was shown to be dependent on the structure of the gels. (C) 1997 Elsevier Science B.V.