Synthesis of ordered large pore SBA-15 spherical particles for adsorption of biomolecules.

The synthesis of spherical particles of mesoporous silicates (SBA-15) with mesopore diameter upto 127A, and particle diameter of 4-10 microm has been achieved. The SBA-15 spheres were obtained using pluronics P123 (EO20PO70EO20) as a surfactant coupled with cetyltrimethylammonium bromide (CTAB) as a co-surfactant. Ethanol played a very important role in the formation of silica spheres, as it delays the reaction rate of the SBA-15 synthesis. A wide range of pore diameters (28-127 A) of these spherical SBA-15 materials with large surface area >700 m2/g has been synthesized. The effects of temperature, ethanol, CTAB and swelling agent have also been studied. The SBA-15 samples were characterized using small angle X-ray scattering (SAXS), N2 adsorption-desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The spherical SBA-15 after mechanical grinding was used for protein adsorption, and adsorption capacity was compared with that of conventional fibrous SBA-15. The spherical SBA-15 particles with pore diameter of 127 A have a very high capacity of 700 mg/g for lysozyme at pH 7.