It is of great significance to separate hazardous methyl tert-butyl ether (MTBE) from water in terms of environmental protection and human health. In the present work, α-Al 2 O 3 -suppotred silica membranes were prepared by the sol-gel and dip-coating technique. Two fluorinated alkylsilanes (1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) and trifluoropropyltriethoxysilane (TFPTES)) and two non-fluorinated alkylsilanes (octyltriethoxysilane (OTES) and propyltriethoxysilane (PTES)) were adopted to silylate the silica membrane by the post-grafting method which is used for the separation of MTBE from water by pervaporation. The results show that silylation enhances the hydrophobicity of silica membranes. The silylated silica membranes are selective towards MTBE, and the MTBE/water separation factor varies with grafting agents in the order: PFOTES > TFPTES > OTES > PTES. Membranes silylated with fluorinated carbon chains seem to be more selective towards MTBE than those with non-fluorinated carbon chains. The total flux is proportional to the pore volume of silica membranes, which depends on grafting agents in the order: PTES > PFOTES > OTES > TFPTES. Considering both total flux and selectivity, the PFOTES-SiO 2 membrane is most effective in separation, with a MTBE/water separation factor of 24.6 and a total flux of 0.35 kg m −2 h −1 under a MTBE concentration of 3.0% and a feed temperature of 30 • C.There are various reports related to the application of ceramic membranes, i.e., TiO 2 , Al 2 O 3 , ZrO 2 , zeolite and SiO 2 membranes in VOCs removal from water [15][16][17][18]23,24]. As a kind of common material, silica membrane has been used in gas separation [25,26], membrane reactor [27], and desalination [28] due to its intrinsic merits, for instance, ease of preparation, tunable pore size, relatively low cost and so on. Pristine silica membrane is generally believed to be hydrothermally unstable owing to the presence of hydrophilic surface hydroxyl groups, which tend to physically adsorb water. The attack of physically adsorbed water leads to further hydrolysis and condensation of silica species, thus resulting in structure deterioration [29]. Fortunately, the hydrothermal stability of silica membrane has been significantly enhanced by replacing hydroxyl groups with hydrophobic groups [26], so that hydrophobic silica membranes can be applied in an aqueous environment such as desalination [28]. To the best of our knowledge, only a few mesoporous silica membranes have been reported previously on the separation of VOCs from aqueous solution by pervaporation [30][31][32]. Pervaporation is considered as a separation process for liquid mixture not only by dense membranes, but also by porous membranes, especially microporous and mesoporous membranes [23,24,31,32]. Compared to conventional separation methods, pervaporation has numerous advantages; for instance, it can be utilized for the separation of azeotropes and close-boiling point mixtures [33]. Pervaporation is advantageous for the separation of VOCs from water...