MONOLITHIC GELS OF SILICA AND NONIONIC SURFACTANT - MATRICES FOR THE DISPERSION OF METAL-IONS

The formation of homogeneous monolithic gels by the addition of TEOS t o acidic amphiphilic solutions has been investigated for a range of no nionic surfactants, and the relationships between solution composition and gelation examined. Using the surfactant solutions as a means of p re-doping the matrices with high concentrations of manganese nitrate g ave gels which could be calcined to 400 degrees C with little or no se gregation of manganese oxide observed by X-ray diffraction. X-ray abso rption spectroscopy has shown that the ligand environment of manganese in the silica-surfactant matrices differs from that in gels derived f rom ethanol solutions, and that most of the manganese in the calcined gels remains in a disordered environment.