Separation of Organic Compounds by Spherical Mesoporous Silica Prepared from W/O Microemulsions of Tetrabutoxysilane

Spherical mesoporous silica (SMS) was prepared in a two-phase system composed of hydrophobic tetrabutoxysilane (TBOS) as the silica source, and an aqueous phase contained dissolved hexadecyltrimethyl ammonium bromide (CTAB) as a surfactant. The adsorption properties of some organic compounds with the as-made and calcined SMS were evaluated by batch and column adsorption experiments. The solubilized quantity of organic compounds with as-made SMS increased with the hydrophobicity of these substances. The breakthrough time obtained by the use of column-packed as-made SMS also increased with the hydrophobicity of organic compounds. Mutual separation of phenol and aniline could also be demonstrated. Separation of organic compounds of different molecular sizes was possible with the column-packed calcined SMS. The pressure drop of the column-packed SMS was lower than that of molded commercial mesoporous silica powder, because of the spherical morphology of the SMS. The breakthrough time for calcined SMS became shorter than that for molded commercial silica powder with MCM41 nanostructure because of the smaller mesopore size.