Study On The Silylation Modification Of MCM-41 Molecular Sieves And Its Adsorption Properties

MCM-41 is the most popular member of mesoporous silicate materials since it has been synthesised in 1992. There are several remarkable features of MCM-41, such as well-defined pore size and shape, fine adjust-ability of the pore size within the limit, hexagonal arrangement of unidimensional channel, high specific surface, and high chemical and hydrothermal stability. Organic-inorganic assembled mesoporous silicas have attracted considerable attention in the fields such as material, physics, and chemistry during the past decade. Such materials possess the synergistic properties of organic- inorganic hybrids, which combine the flexibility and reactivity of tailored organically functional group swith the structural robustness and chemical inertness of the inorganic ordered silicas with controllable arehitectur, exceptionally high surface area and uniform pore size. The surface of MCM-41 is consisted of amounts of free silicon hydroxyl—SiOH and =Si(OH)₂, which can react with siliconalkyls, and can introduce alkyl, amido, and sulfur hydroxyl into MCM-41. Thus, the different functional groups can be introduced by these active groups. The new organic-inorganic assembled mesoporous silicas have been synthesized.In this paper, we prepared a series of organo-functionlized mesoporous silicas of MCM-41 via a post-grafting method. The main contents are as follows:1. MCM-41 has been successfully synthesized with CTAB as templates under a certain temperature, then organo-functionlized groups are prepared by post-grafting method, using trimethylchlorosilane as silylation reagents. It is demonstrated that the organic group has been bonded to both the internal and external surface of mesoporous silicas by the characterized methods, such as XRD, IR and N₂ adsorption. The original structure has maintained after silylation, except that the order degree decreases to some extent.2. The adsorption properties of MCM-41 and funtionalized MCM-41 to water and benzene have been measured and compared. The results show that the adsorption quantity to benzene decreases slightly, whereas the adsorption ability to water reduces significantly. The polarization of MCM-41 varies before and after silylation, consequently, the silylized MCM-41 could be a kind of good separation material and new technologic materials for enviormental chemistry fields. Also, the silylized materials have the meaning for research of substance with organic-inorganic hybrid materials.