Preparation, characterization and kinetics studies of mesoporous silica from alkali dissolution of kaolinite

In search of cheaper and ecologically friendly material for porous silica preparation, thermal activated kaolinite was subjected to alkaline dissolution using NaOH solution. The result showed experimental reaction parameters such as alkali concentration, reaction temperature and liquid/ solid ratio affected the rate of silica extraction. At optimized condition, silica extraction reached 54.2% with apparent activation energy of 14.43 kJ/mol. The porous product was characterized by XRF, XRD, SEM, TEM and N2 adsorption-desorption. The product was amorphous with silica agglomerates. The pore size distribution by the BJH method was mesoporous with specific surface area of 10.36 m2/g and pore size of about 10.43 nm at maximum probability.