ABSTRACT
Ordered mesoporous silica was synthesized by the sol-gel process using tetraethoxysilane (TEOS) as silica source and hexadecyltrimethyl ammonium bromide (CTAB) as structure directing agent. Post-synthesis surfactant removal was conducted by two techniques: calcination, with progressive increases in temperature up to 550 ºC and solvent extraction using HCl /EtOH as extracting solution. In the last mentioned technique, a few experimental variables were changed such as the acid concentration, the volume of extracting solution, the reflux time and the solvent employed for washing. The samples were characterized by N2 adsorption, FTIR spectroscopy and SEM.
Both the synthesis technique used and the procedures to remove template lead to MCM-41 type material. Template extraction by calcination results in materials having a surface area of 1100 m2/g. On the other hand, extraction with HCl/EtOH leads to decreases in surface area, attributed to occlusion of the pores with organic material. In both cases, monitoring surfactant traces in the samples was performed using FTIR.
Keywords
Mesoporous silica; MCM-41; Sol-gel technique; TEOS; CTAB
