The State of Silanol Coverage of the Mesostructured Silicate Material MCM-41 as a Result of Postsynthetic Activation

Full text (.pdf)
Issue
Химия. Chemistry. 2008 1 (4)
Authors
Kozlova, Svetlana A.; Parfenov, Vladimir A.; Tarasova, Ludmila S.; Kirik, Sergey D.
Contact information
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
Keywords
SiO2; MCM‑41; mesostructured mesoporous silicate; silanol number; thermogravimetric analysis; XRD; IR-spectroscopy
Abstract

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.

Pages
376-388
Paper at repository of SibFU
http://elib.sfu-kras.ru/handle/2311/910