A molded carbon/silica composite with high micro- and mesoporosity, as well as a high bulk density, was
fabricated by activating a disk-molded precursormadefrom carbonized rice husk (RH) and beet sugar (BS)
at 875 ◦C in CO2. The pore structure of the RH- and BS-based carbon/silica composite (RBC) was analysed
in relation to the bulk density. An activation time of 2.0 h provided the largest BET specific surface area
(1027m2/g) and total pore volume (0.68cm3/g) and a low bulk density (0.54 g/cm3). An RBC that was
first activated for 1 h was immersed again in BS syrup and then activated in CO2 for 1 h. This two-step
activation process provided both a high bulk density (0.69 g/cm3) and a highly textured structure (BET
specific surface area, 943m2/g; total pore volume, 0.56cm3/g). The immersion in BS syrup was useful for
improving the texture without reducing the bulk density, in comparison to one-step activation for 1.0 h.
The suspension of the RBCs was basic because of the residual inorganic compounds of potassium and
calcium. However, the basicity of the suspension was alleviated by washing the RBCs with water.