Surfactant (2.0 wt.%) was dissolved in the water/butanol
(1:1) solvent. Subsequently, RHA-derived sodium silicate
was slowly added into the CTAB/water/butanol solution,
and the mixture was stirred at 60°C. Then, 0.5 mol/L
sulfuric acid solution was added gradually into the suspension
in order to initiate the hydrolysis-condensation
reaction at pH ~ 4. The resulting gel mixture was aged
at 60°C for 8 h.