1997 Volume 70 Issue 5 Pages 300-307
A new modification of silica powder (Aerosil) with sulfonic acid group was achieved. A new alkoxysilane containing isopropyl sulfonate group [(CH3O) 3Si (CH3) 3SO3CH (CH3) 2, [3- (Trimethoxysilyl) propyl] isopropylsulfonate, TIS]] was prepared. Through fixation and pyrolysis of TIS on silica surfaces, new surface-modified Aerosil (SMA) with sulfonic acid group was obtained. Conversion from isopropyl sulfonate group to sulfonic acid group on silica surface was reached 90%.
It was revealed that the new SMA had the following properties : (1) high trapping ability for several cations (Na+, Ca2+, Cu2+ and Fe3+ : ca. 0.3mmol/g) and (2) high dispersibility in water. The adsorption equilibrium was reached within several seconds. The adsorption amount was not influenced by the concentration of the cations in aqueous solution. The new SMA showed homogeneous dispersion after two-week standing in pH 2. Some mechanisms originated from sulfonic acid functional group were presumed for these properties.
