Silicalite-1 membranes preparation

Lin, X., Kita, H., Okamoto, K. I. (2001). Silicalite membrane preparation, characterization, and separation performance. Industrial and Engineering Chemistry Research, 40, 4069—4078. 

Lopez F, Bernal MP, Mallada R, Coronas J, and Santamaria J. Preparation of silicalite membranes on stainless steel grid supports. Ind Eng Chem Res 2005 44 7627-7632. 

Fig. 5. FESEM observations of the MFI membranes prepared at different temperatures, by MW-assisted secondary growth, from a layer of MW derived silicalite-I seeds [101 ].

Supported zeolite Y, silicalite-1, A and a composite of silicalite-1 on A can be synthesised in a membrane configuration in a reproducible manner. Synthesis techniques using seeds were applied in the membrane preparation. The double layer type membrane has great potential in the bifunctional operation in one integrated unit. 

Takata. Y. Tsuru, T. Yoshioka, T. Asaeda. M. Gas permeation properties of MFI zeolite membranes prepared by the secondary growth of colloidal silicalite and application to the methylation of toluene. Microporous Meso-porous Mater. 2002, 54, 257-268. 

Pure silica microporous solids show no such strong affinity for polar molecules, and are of interest to separate hydrocarbon molecules of different shapes. In particular, the separation of xylene isomers is of great industrial significance, and since the relative diffusivities of the para isomer are known to be much higher than those of the ortho (and meta) isomers within silicalite, the preparation of silicalite membranes is an attractive target. If the aluminium content can be made vanishingly small, the membranes can be used for hydrocarbon separation at elevated temperatures without the effects of coke formation due to catalytic reaction. 

Supercritical CO2 activation of a Naflon membrane prior to zeolite deposition was used to modify its structure. The resultant Nafion-zeolite composite membranes showed a dramatic decrease in methanol permeability (if the colloidal rather than the suspended Fe-silicalite-1 particles were used for the deposition) and a 19-fold higher selectivity compared with either the composite membranes prepared without previous supercritical treatment or the pure commercial Nafion-115 membrane. The method of the in situ synthesis of a zeolite inside the membrane pores was found to be very effective for preparing the composites, giving a sixfold higher selectivity for the composite manbrane compared with the pure Nation membranes (Gribov et al. 2007). 

Silicalite membranes, supported on porous alumina tube, have been prepared by two-step hydrothermal synthesis. The pore structure and zeolite of membrane layer has been characterized by XRD, SEM and nano-permporosimetry technique. The permeabilities of several vapors have been measured together with vapor mixture separation behavior. 

Two silicalite membrane tubes have been prepared in same procedure at experiment sectioiL Prepared silicalite mmnbrane observed by SEM (Fig.4, S). San le A has 18.4 pt m. Sample B has 4.5 p. m thickne of silicalite layer on the outer surflice of a-Alumina sqip rt. By SEM observation, it is very difiicult to find defect of membrane quality. 

The silicalite-alumina membrane was prepared after adding a solution containing the silicalite precursor (i e silica + template) to the above-mentioned porous tube (hereafter called support) and a specific hydrothermal treatment performed [8], under the chosen conditions no material is formed in the absence of the porous support. The tube is then calcined at 673 K for removing the template. 

Jia and coworkers prepared thin-film composite zeolite-filled silicone rubber membranes by a dip-coating method [82]. The membranes have a thin silicalite-1/ silicone rubber mixed-matrix selective layer on top of a porous polyetherimide support. 

Chen, H Li, Y and Yang, W. (2007) Preparation of silicalite-1 membrane by solution-filling method and its alcohol extraction properties. J. Membr. Sci., 296, 122-130. 

Jia et al. [1993] have prepared thin, dense pure silicalite zeolite membranes on porous ceramic supports by an in-situ synthesis method. A sol consisting of silica, sodium hydroxide, tctrapropylammonium bromide and water is prepared with thorough mixing. A ceramic support is immersed in the sol which is then heated and maintained at 180X... 

The first reported zeolite-based membranes were composed of zeolite-filled polymers [3-9]. The incorporation of zeolite crystals into these polymers resulted in a change of both permeation behavior and selectivity, due to the alteration of the affinity of the membrane for the components studied. Up to now, most known inorganic, zeolitic membranes have consisted of supported or unsupported ZSM-5 or silicalite [10-27]. Other reported membranes are prepared from zeolite-X [21], zeolite-A [21,28], or AIPO4-5 [29]. The materials used as support arc metals, glass, or alumina. The membrane configurations employed are flat sheet modules and annular tubes. 

MasudaT, Otani S, Tsuji T, KitamuraM, andMukai SR. Preparation of hydrophilic and acid-proof silicalite-1 zeolite membrane and its application to selective separation of water from water solutions of concentrated acetic acid by pervaporation. Sep Purif Technol 2003 32(1-3) 181-189. 

Thin zeolite membranes can also be prepared through a spin-coating process of a nanoparticle suspension. Yan and coworkers synthesized silicalite-1 and silicalite-2 in a nanoparticle suspension using a two-stage hydrothermal process.[138,139] First, the precursor... 

P. Meriaudeau, A. Thangaraj and C. Naccache, Preparation and characterization of silicalite molecular sieve membrane over supported porous sintered glass. Paper presented at the 1st International Workshop of Catalytic Membranes, September 1994, Lyon-ViUeurbanne, France. 

E. Mateo, R. Lahoz, X. de la Puente, A. Paniagua, J. Coronas, J. Santamaria, Preparation of silicalite micromembranes on laser perforated stainless steel sheets in Proc. 3rd Int. Zeolite Membrane Meeting, R. Noble (Ed), Breckenridge, CO USA, July 25-28, 2004. 

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