Synthesis of Si-MCM-48 membrane by solvent extraction of the surfactant template

Abstract

Mesoporous MCM-48 silica membranes have been synthesized on porous supports under hydrothermal conditions, using tetraethyl orthosilicate (TEOS) as silica source, cetyltrimethylammonium bromide (CTAB) as template surfactant. And then the templates were removed by solvent extraction instead of calcination. The results of the TG and FT-IR showed that the solvent of 1M HCl/EtOH solution was feasible to extract the templates in the MCM-48 materials and over 90% of the templates were extracted at room temperature for 24h. The results of XRD, SEM indicated that the MCM-48 membranes were prepared on the porous supports and extraction did not destroy the mesostructure of the MCM-48. The compactness of the extracted MCM-48 membrane was evaluated by the permeation of single gas (N2 and H2) with transmembrane pressure of 60–220kPa. The permeance of N2 was independent of the transmembrane pressure and the ideal separation factor was about 3.45. All the results demonstrate that the method, solvent extraction to remove surfactant template, is more effective to synthesize high quality MCM-48 membranes than calcination.