A porous support-zeolite membrane composite comprising an inorganic porous support and a zeolite membrane provided on, wherein the zeolite membrane contains a zeolite having a microporous structure of 8-membered oxygen ring or less, and a molar ratio of SiO.sub.2/Al.sub.2O.sub.3 in the zeolite membrane surface is larger by at least 20 than a molar ratio of SiO.sub.2/Al.sub.2O.sub.3 in the zeolite membrane itself, or a water adsorption of the porous support-zeolite membrane composite at a relative pressure of 0.8, as determined from a water vapor adsorption isotherm of the porous support-zeolite membrane composite, is at least 82% of a water adsorption of the porous support-zeolite membrane composite under the same condition as above after one-week immersion of the porous support-zeolite membrane composite in an aqueous 90 mass % acetic acid solution at room temperature.

The present invention relates to a process for producing a porous support-zeolite membrane composite, which comprises forming a CHA type zeolite membrane on a porous support by a hydrothermal synthesis in the presence of seed crystals, wherein an FAU type zeolite is used as the seed crystals.

Provided are an all-silica zeolite separation membrane for separating carbon dioxide, etc., and not causing a decrease in the processing amount due to adsorption of water molecules, and a production method therefor. One aspect of the present invention is a zeolite separation membrane, in which the framework of a zeolite crystal structure formed on a porous support is all silica, characterized in that the zeolite crystal structure formed on the porous support is fluorine free. Another aspect of the present invention is a method for producing a zeolite separation membrane having a zeolite crystal structure on a porous support, characterized in that the method includes a step of producing a seed crystal, a step of applying the seed crystal onto the porous support, a step of producing a membrane synthesis raw material composition, and a step of immersing the porous support having the seed crystal applied thereon in the membrane synthesis raw material composition and performing hydrothermal synthesis, and the membrane synthesis raw material composition contains a silica source and an organic template and does not contain a fluorine compound.

Systems, devices and methods for molecular separation including a molecular separation device comprising at least a polycrystalline metal-organic framework (MOF) and a nanocrystalline, zeolite MFI, wherein the MOF forms a polycrystalline membrane with zeolite MFI nanoparticles dispersed therein, and the MOF membrane matrix contacting and surrounding the zeolite MFI nanoparticles form a permselective nanoporous structure.

Disclosed is a method of manufacturing a partially freestanding two-dimensional crystal film (16, 16′), the method comprising providing a substrate (10) carrying a catalyst layer (14) for forming the two-dimensional crystal layer on a first surface; forming the two-dimensional crystal film on the catalyst layer; covering at least the two-dimensional crystal film with a protective layer (18); etching a cavity (24) in a second surface of the substrate, the second surface being opposite to the first surface, said cavity terminating on the catalyst layer; etching the exposed part of the catalyst layer from the cavity; and removing the protective layer, thereby obtaining a two-dimensional crystal film that is freestanding over said cavity. A device manufactured in this manner is also disclosed.

The present invention provides a titanosilicate separation membrane which can also be used for separating a mixed gas containing a molecule having a relatively small size, has high durability in a high temperature environment, and has a high permeation rate and a high selectivity for a mixed gas containing water vapor. A titanosilicate separation membrane has a CHA-type titanosilicate crystal structure formed on a porous support, wherein aluminum is not substantially contained in the backbone of the titanosilicate crystal structure, and the titanosilicate crystal structure is constituted by silicon, oxygen, and titanium.

A porous cylindrical support for use in supporting a zeolite membrane has a generally cylindrical inside surface having a central axis extending in the longitudinal direction and a generally cylindrical outside surface that surrounds the inside surface. A zeolite membrane is formed on the outside surface. A maximum value A and a minimum value B of a support thickness in a circumferential direction satisfy (A−B)/(A+B)≤0.3 in at least part of the support in the longitudinal direction, the support thickness being a radial distance between the inside surface and the outside surface. By reducing a variation in support thickness, it is possible to improve uniformity in the thickness of the zeolite membrane formed on the support.

Provided is a method of producing a zeolite film continuously and efficiently. Zeolite is formed on a surface of a support using a method including: a first step of attaching zeolite fine crystals to a surface of a support; a second step of preparing synthetic gel for growing the fine crystals; a third step of putting the support and the synthetic gel into a reactor and performing hydrothermal synthesis; and a fourth step of cleaning the support subjected to the hydrothermal synthesis, in which in the third step, multiple containers arranged to be movable in a constant-temperature apparatus are each used as the reactor, the temperature and pressure for the hydrothermal synthesis is adjusted by the temperature and pressure in the constant-temperature apparatus, and the reaction time of the hydrothermal synthesis is adjusted by setting the time from when the reactor enters the constant-temperature apparatus to when the reactor exits the constant-temperature apparatus.

A zeolite membrane complex includes a longitudinal support member having at least one through hole extending along its length and a zeolite membrane on an inner peripheral surface of the through hole or over an outer peripheral surface of the support, from one end portion of the support to the other end portion thereof. Among constituent elements of the zeolite membrane except oxygen, an element with the highest percentage is a main element, and when the concentration of the main element is measured at three portions defined by dividing the support into three equal parts in the longitudinal direction, the concentration of the main element gradually decreases from the one end portion toward the other end portion, and the ratio of the concentration of the main element at the other end portion-side to that at the one end portion is 0.90 or more.

A zeolite synthesis sol includes particles of an aluminum source with a mean particle diameter of 5 to 500 nm, and a solvent in which the particles are dispersed, the solvent being water that contains a phosphorus source, a structure-directing agent, and a carboxylic acid.