One object of the present invention is to provide a zeolite membrane that can achieve both practically sufficient separation performance and throughput and maintain the separation performance stably for a long period. Provided is a method of producing a zeolite membrane having CHA crystal structure on an intermediate layer of a porous support, wherein Si/Al (a molar ratio) of CHA zeolite particles is from 9.5 to 100.5 and, in an X-ray diffraction pattern obtained by applying X-ray onto a surface of the zeolite membrane, a peak intensity near 2=18 is less than 0.5 times a peak intensity near 2=21, and/or a peak intensity near 2=10 is less than 4 times a peak intensity near 2=21, the method including: forming the zeolite membrane having the CHA crystal structure on the intermediate layer of the porous support by hydrothermal synthesis, using an aqueous reaction mixture including a Si element source, an Al element source, an alkali source, and an organic template, wherein non-dealuminated FAU zeolite is used as the Si element source and the Al element source.

A dehydration method is a dehydration method for selectively separating water from a mixture that contains water, using a zeolite membrane having an AFX structure, and the method includes a step of supplying the mixture to a supply side space of the zeolite membrane having an AFX structure, and a step of making a pressure difference between the supply side space and a permeation side space of the zeolite membrane having an AFX structure.

The present invention addresses the problem of providing a separating membrane mainly comprising a thermoplastic resin having high permeability. The present invention relates to a separating membrane including a thermoplastic resin, wherein the width of voids in the separating membrane is at least equal to 1 nm and at most equal to 1000 nm, and the curvature rate of the voids is at least equal to 1.0 and at most equal to 6.0.

A peak intensity of a (002) plane is greater than or equal to 0.5 times a peak intensity of a (100) plane in an X-ray diffraction pattern obtained by irradiation of X-rays to a membrane surface of the ERI membrane.

A method of synthesis for an aluminophosphate-based zeolite membrane includes a steps of preparing a mixed solution with a pH greater than or equal to 6 and less than or equal to 9 by mixing an acidic phosphorous source with an alkali source, a steps of preparing a starting material solution by adding and mixing an aluminum source to the prepared mixed solution, and a steps of synthesizing an aluminophosphate-based zeolite membrane by hydrothermally synthesizing the starting material solution.

A process for producing a zeolite membrane composite includes a step of obtaining FAU-type seed crystals, a step of depositing the FAU-type seed crystals on a support, a step of forming an AFX-type zeolite membrane on the support by immersing the support in a raw material solution and growing an AFX-type zeolite from the FAU-type seed crystals by hydrothermal synthesis, and a step of removing a structure-directing agent from the AFX-type zeolite membrane. In this way, the AFX-type zeolite membrane can be provided.

Porous liquid-filtering membranes are provided having a boundary region substantially surrounding the pore region and having greater tear resistance than the pore region.

There is provided a method of producing a separation membrane in which a zeolite membrane is formed on an inorganic oxide porous substrate. The substrate has amorphous SiO.sub.2 as a main component of a zeolite formation portion of the substrate, the method includes: a first step of forming a zeolite seed crystal and an alkaline component including a structure directing agent on a surface of the substrate; and a second step of treating a formed product obtained in the first step under a heated steam atmosphere, and the zeolite membrane is formed on the surface of the substrate.

Porous liquid-filtering membranes are provided having a boundary region substantially surrounding the pore region and having greater tear resistance than the pore region.

Seed crystals are crystals of zeolite to be attached onto a support in production of a zeolite membrane complex including the support and a zeolite membrane formed on the support. The specific surface area of the seed crystals is not smaller than 10 m.sup.2/g and not larger than 150 m.sup.2/g. The strength obtained from a crystal component at a diffraction angle 2 indicating a maximum peak in a range of diffraction angle 2 from 12 to 25 in an X-ray diffraction pattern obtained by emitting X-ray to the seed crystals is not less than once and not more than 30 times that obtained from an amorphous component. It is thereby possible to improve adherence of the seed crystals to the support.