Investigation of the Structural Characterization of Mesoporous Molecular Sieves MCM‐41 from Sepiolite

Mesoporous molecular sieves, MCM‐41, were synthesized from sepiolite using acid leaching, followed by hydrothermal reconstruction and then calcinations at 540°C for 5 h. The structures and the porosity of MCM‐41 were investigated by means of small‐angle X‐ray diffraction patterns, Brunaer‐Emmett‐Teller (BET), 29Si MAS NMR, Fourier transform infrared (FTIR), and high resolution transmission electron microscope (HRTEM) methods. The results showed that the hexagonal MCM‐41 was formed in an alkaline solution of pH 12, when crystallization was carried out at 100°C for 24 h. The specific surface area, pore diameter, and pore volumes of MCM‐41 from sepiolite were 1036 m2/g, 2.98 nm, and 1.06 cm3/g, respectively. 29Si MAS NMR results revealed that amorphous silica decomposed into Si–O chains consisting of two layers of Si atoms, with Q3 configurations resulting in an increase in the fraction of Q3 configuration during the crystallization of post‐Mg‐extraction sepiolite. The IR results illustrated that the complex of ≡≡SiO−–CTA+ was formed during the synthesis of MCM‐41 from post‐Mg‐extraction sepiolite.