Provided herein are methods for making a freeze-cast material having a internal structure, the methods comprising steps of: determining the internal structure of the material, the internal structure having a plurality of pores, wherein: each of the plurality of pores has directionality; and the step of determining comprises: selecting a temperature gradient and a freezing front velocity to obtain the determined internal structure based on the selected temperature gradient and the selected freezing front velocity; directionally freezing a liquid formulation to form a frozen solid, the step of directionally freezing comprising: controlling the temperature gradient and the freezing front velocity to match the selected temperature gradient and the selected freezing front velocity during directionally freezing; wherein the liquid formulation comprises at least one solvent and at least one dispersed species; and subliming the at least one solvent out of the frozen solid to form the material.

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 (AB)/(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 piperylene from a hydrocarbon mixture derived from a petroleum fraction having a carbon number of 5. The hydrocarbon mixture has a piperylene proportional content of not less than 60 mass % and not more than 80 mass % and has a cyclic hydrocarbon proportional content of not less than 20 mass % and not more than 40 mass %. The method of producing piperylene includes a membrane separation step of performing membrane separation of the hydrocarbon mixture using a zeolite membrane to obtain a separated product in which piperylene is enriched.

The present invention relates to a method of controlling a defect structure in a chabazite (CHA) zeolite membrane, the CHA zeolite membrane having a controlled defect structure by the method and a method of separating CO.sub.2, H.sub.2, or He and water from a mixture of water and an organic solvent using the CHA zeolite membrane, and more particularly, to a method of controlling a defect structure in a CHA zeolite membrane that improves the separation performance by reducing the amount and size of defects formed in the CHA membrane structure when removing organic-structure-directing agents in the membrane through calcination at a low temperature using ozone.

There is provided a zeolite membrane which is an MFI-type zeolite membrane formed on an inorganic oxide porous substrate, in which, in a diffraction pattern obtained by X-ray diffraction measurement using a CuK ray as an X-ray source, when an intensity of a diffraction peak appearing at diffraction angles of 7.3 to 8.4 at which a crystal lattice plane belongs to 011 and/or 101 planes is used as a reference, an intensity of a diffraction peak appearing at diffraction angles of 8.4 to 9.0 at which a crystal lattice plane belongs to 200 and/or 020 planes is preferably 0.3 or more.

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.

Provided is a method for preparing a defect-free DDR molecular sieve membrane. Sigma-1 molecular sieve is used as an inducing seed crystal to prepare and obtain a continuous and compact DDR molecular sieve membrane on the surface of a porous ceramic support. An ozone atmosphere or an external field assisted technology is used to remove a template in the pores of the molecular sieve membrane at a low temperature. The invention avoids the formation of intercrystal defects and cracks, an activated DDR molecular sieve membrane has a good selectivity for separating CO2, and the membrane preparation time is significantly reduced.

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.

A method of producing a separation membrane includes a seed crystal adhesion step of adhering zeolite seed crystals to a porous support formed of stainless steel to obtain a seed crystal-bearing support and a separation layer formation step of forming a porous separation layer formed of a zeolite on the seed crystal-bearing support. The stainless steel has a contact angle with water of 90? or more. The seed crystal adhesion step includes bringing the zeolite seed crystals and a solvent having a contact angle with the stainless steel of 30? or less into contact with the porous support.

A zeolite membrane composite includes a porous support and a zeolite membrane formed on at least one surface of the porous support. The zeolite membrane of the zeolite membrane composite is formed of an X-MOR-type zeolite, where X includes at least one type of transition metal ion.