Disclosed is a membrane surface modification method. The method is applicable to a variety of hydrophobic membranes by doping selected inorganic particles. One act of the method involves the in-situ embedment of the inorganic particles onto the membrane surface by dispersing the particles in a non-solvent bath for polymer precipitation. Further membrane surface modification can be achieved by hydrothermally growing new inorganic phase on the embedded particles. The embedment of particles is for the subsequent phase growth.

A zeolite membrane structure includes a porous support, and a zeolite membrane. The zeolite membrane has a first zeolite layer located in a surface of the porous support, and a second zeolite layer located outside of the surface of the porous support and integrally formed with the first zeolite layer. The porous support has an outermost layer in which the first zeolite layer is located. An average thickness of the first zeolite layer is less than or equal to 5.4 micrometers. A porosity of the outermost layer is greater than or equal to 20% and less than or equal to 60%.

The present invention addresses the problem of providing a technology for efficiently separating carbon dioxide in a method for separating carbon dioxide from a mixed gas by using a membrane separation method. The problem is solved by a method including supplying a mixed gas to a separation membrane module to separate carbon dioxide from the mixed gas, in which the mixed gas is supplied to the separation membrane module at a high linear velocity in order to sufficiently mix a mixed gas in the vicinity of a membrane.

In a first aspect, the present disclosure relates to a method for forming a diamond membrane, comprising: providing a substrate having an amorphous dielectric layer thereon, the amorphous dielectric layer comprising an exposed surface, the exposed surface having an isoelectric point of less than 7, preferably at most 6; seeding diamond nanoparticles onto the exposed surface; growing a diamond layer from the seeded diamond nanoparticles; and removing a portion of the substrate from underneath the diamond layer, the removed portion extending at least up to the amorphous dielectric layer, thereby forming the diamond membrane over the removed portion.

An asymmetric membrane having a layer containing a zeolite supported on a geopolymer substrate and methods for making an asymmetric membrane having a layer containing a zeolite supported on a geopolymer substrate. A cross-flow membrane separation method for increasing the concentration of ethanol from a feed mixture comprising water and ethanol, comprising: cross-flowing a feed mixture comprising water and ethanol across the layer comprising a zeolite of the asymmetric membrane of the instant invention to produce a permeate having an ethanol concentration less than the ethanol concentration of the feed mixture and a retentate having an ethanol concentration greater than the ethanol concentration of the feed mixture, the pressure of the feed mixture being greater than the pressure of the permeate.

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.

The present invention relates to a method of controlling a defect structure in an MFI zeolite membrane and a method of separating xylene isomers using the MFI zeolite membrane produced by the method, and more particularly, to a method of controlling a defect structure in an MFI zeolite membrane that improves the performance of separating a xylene isomer by reducing the amount and size of defects formed in the MFI membrane structure when removing organic-structure-directing agents in the membrane through calcination at a low temperature using ozone.

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.

A peak intensity of a (004) plane is greater than or equal to 3 times a peak intensity of a (110) plane in an X-ray diffraction pattern obtained by irradiation of X-rays to a membrane surface of an AFX membrane.

Disclosed are a method of preparing carbon-dioxide-selective separation membranes by controlling calcination conditions including rapid thermal processing and separation membranes produced thereby. More particularly, disclosed are a method of preparing carbon-dioxide-selective separation membranes that can improve CO.sub.2 permselectivity, particularly, exhibit excellent CO.sub.2 permselectivity in the presence of water in the feed gas, by controlling the size of defects in the separation membranes using rapid thermal processing, separation membranes produced thereby, and a method of capturing and removing carbon dioxide using the separation membranes.