Mesoporous silicas prepared from sodium silicate using gelatin templating

Abstract

ABSTRACTGelatin was employed as a templating agent for the preparation of mesoporous silica materials starting from sodium silicate solutions using a sol‐gel method. The silicate anions were first transformed into silicic acid by passing the solution through an H+ ion‐exchange resin, then mixed with acidic gelatin solution prior to adjustment of the pH to approximately 9–10. Gelatin was removed by solvothermal Soxhlet extraction to form pores. We show that gelatin can serve as a structure‐directing agent resulting in silica structures with pores spanning a range of 3–12 nm depending on gelatin concentration. Increasing gelatin concentration resulted in a larger pore size and a wider pore‐size distribution. This dependence was also observed for the surface area and pore volume but only at low gelatin concentration (<0.4 wt%). The surface area and the pore volume tended to decrease with increasing gelatin concentration at high gelatin concentration (>0.4 wt%). Mesoporous silica with a high specific surface area (426.6 m2 g−1), high pore volume (0.9 cm3 g−1) and large pore diameter (8.4 nm) was obtained at a gelatin concentration of 0.41 wt%. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.