The use of an impure inorganic precursor for the synthesis of highly siliceous mesoporous materials under acidic conditions

Highly ordered mesoporous silica materials have been synthesized under acidic conditions using an industrial waste-product containing only 42 wt% silica as the precursor, using formic acid as pH-regulator. Non-ionic tri-block-co-polymers of the ABA type were used as the structure-directing agents, and high-quality SBA-15 and KIT-5 materials were obtained. The materials were characterized by small-angle X-ray diffraction, nitrogen physisorption, transmission electron microscopy, and elemental analysis. The methodology presented here is suggested to be widely applicable for the synthesis of siliceous materials using other impure inorganic silica precursors with different purity, as long as the precursors are soluble under acidic conditions.