The method of MCM-41 synthesis was taken place at room temperature under atmospheric
condition, following the previous study [10]. Hexadecyltrimethylammonium bromide (CTAB) and
two sources of silica; silica extracted from rice husk ash, and commercial sodium silicate, were used as
reactants for MCM-41 synthesis; as named RHA_MCM-41 and SDS_MCM-41, respectively. The
process of synthesis, called sol-gel method, was carried out with the molar composition of 4SiO2:
1Na2O: 1CTAB: 200H2O. The mixture was adjusted the pH value to 10 and stirred constantly for 48 h
at room temperature. Afterward, the suspended solid was filtered and rinsed with ethanol solution. The
filtered solid was calcined at 550 °C for 5 h and kept in the desiccator before characterizations.