Modification of porous silica with activated carbon and its application for fixation of yeasts

Mixtures of small silica particles and activated carbon were heated at 1250-1450°C in an inert atmosphere to make nano- and macro-sized porous silica for incorporating yeast in the porous structure. Without activated carbon, porous silica of 45-60% porosity and 15-30 μm pore diameter was produced with a specific surface area below 1 m²/g. By the addition of 8 wt% of activated carbon granules, the surface area of porous silica increased to 100 m²/g at 1250°C. It was confirmed that there were micropores (1.2 nm) and mesopores (4.0 nm) due to activated carbon granules in porous silica when granule type activated carbon was used. However, in the case of activated carbon fiber, its micro- and mesoporous structure was destroyed in the firing process. The fixation of Z. rouxii yeasts was promoted on the porous silica with activated carbon.