Journal of Siberian Federal University. Chemistry / The State of Silanol Coverage of the Mesostructured Silicate Material MCM-41 as a Result of Postsynthetic Activation

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Journal of Siberian Federal University. Chemistry: 2008, Vol. 1, Issue 4
Kozlova, Svetlana A.; Parfenov, Vladimir A.; Tarasova, Ludmila S.; Kirik, Sergey D.
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Светлана А. Козлова, Владимир А. Парфенов: Институт химии и химической технологии СО РАН, ул. К. Маркса, 42, Красноярск, 660049 Россия, e-mail: ; Людмила С. Тарасова: Красноярский научный центр СО РАН, Академгородок, 50, Красноярск, 660036 Россия; Сергей Д. Кирик: Институт химии и химической технологии СО РАН, ул. К. Маркса, 42, Красноярск, 660049 Россия, Сибирский федеральный университет, пр. Свободный, 79, Красноярск, 660041 Россия
SiO2; MCM‑41; mesostructured mesoporous silicate; silanol number; thermogravimetric analysis; XRD; IR-spectroscopy

The influence of various types of postsynthetic activations (calcination, treatment in neutral, acid and alkaline water mediums at 100°С, in hydrofluoric acid) on the state of silanol coverage of mesostructured silicated material MCM-41 surface was studied. The surface was characterized by XRD, IR-spectroscopy, thermogravimetric analysis and nitrogen adsorption. Activation of surface resulted in increasing silanol groups concentration. There was found the limit of the silanol number for МСМ-41, beyond which the material destruction caused because of structure features. The value of critical silanol number is 3-4 OH/nm2 for water solutions at 100°С. In spite of a destruction the specific characteristics of a material (the internal surface, volume, parameter of a lattice) remain invariable. Thus, there are limits on activation of a surface. The composition of reaction solution influences the rate of material collapse, but does not influence density of silanol coverage.

Paper at repository of SibFU