Carminic acid was adsorbed into amorphous silicas prepared by the sol−gel process. While cromophoreis gradually released in silica when put in contact with water, irreversible adsorption takes place whensilica is doped with aluminum. The role of aluminum on effective retention of carminic acid by aluminicsilicas is described. A fractal geometry approach was employed to describe changes in silica sampleswhen they are doped with aluminum and when chromophore is incorporated. Inclusion of chromophoreprovokes aggregates to form interconnected fractal surfaces.
Carminic acid was adsorbed into amorphous silicas. Cromophore leaches gradually in silica when put in contact with water. When silica is doped with aluminum carminic acid, adsorption is enhanced. Inclusion of chromophore provokes aggregates to form interconnected fractal surfaces.