Spherical Silica Gel Beads with Macropores Prepared from Water Glass

Production method of spherical silica beads with macropores was investigated from water glass. Spherical beads with continuous macropores were obtained by inducing phase separation in sol droplets in an organic solvent, and the diameter of beads was controlled between 0.7 and 2.8 mm by changing volume of droplets. The macroporous silica beads have dense external surface layer with thickness of ca. 2 μm. The surface layer was removed by soaking the wet gel in 1 mol dm-3 HF solution for 10 s before drying.