The present invention provides a fluid separation membrane that can maintain separation performance for a long period of time. The present invention provides a fluid separation membrane including a separation layer including a dense layer, wherein 2 to 10,000 ppm of a total of a monocyclic or bicyclic aromatic compound being liquid or solid at 16 C. under atmospheric pressure and 10 to 250,000 ppm of water are adsorbed.

Disclosed herein are porous asymmetric silicon membranes. The membranes are characterized by high structural stability, and as such are useful as anode components in lithium ion batteries.

A carbon molecular sieve (CMS) membrane having improved separation characteristics for separating olefins from their corresponding paraffins is comprised of carbon with at most trace amounts of sulfur and a group 13 metal. The CMS membrane may be made by pyrolyzing a precursor polymer devoid of sulfur in which the precursor polymer has had a group 13 metal incorporated into it, wherein the metal is in a reduced state. The pyrolyzing for the precursor having the group 13 metal incorporated into it is performed in a nonoxidizing atmosphere and at a heating rate and temperature such that the metal in a reduced state (e.g., covalently bonded to carbon or nitrogen or in the metal state).

An ultrathin high permselectivity carbon molecular sieve membrane (CMSM) for industrial gas separations is provided. The CMSM includes porous metal or ceramic supports to provide superior stability at high temperatures, pressures and chemical environments. The CMSM also offers the potential for cost-effective gas processing while overcoming disadvantages found in alternative media that are fragile and susceptible to shock due to thermal cycling and prone to end-sealing problems under industrial conditions.

A method of making a hollow fiber carbon molecular sieve is comprised of heating a hollow polymer fiber to a carbonization temperature in an atmosphere that is non-oxidizing to form a hollow fiber carbon molecular sieve, wherein during at least a portion of the heating a tensile force is applied to the hollow polymer fiber. The method may improve the separation of gases similar in size such a propylene from propane.

The present disclosure describes a process for separating at least a first gas component and a second gas component by contacting a gas stream comprising the first and second gas components with a carbon molecular sieve (CMS) membrane under aggressive gas separation conditions in which the partial pressure of the selectively sorbed gas component in the gas stream is high. Despite the high partial pressure of the sorbed gas component, the selectivity of the carbon molecular sieve membrane is not substantially reduced by plasticization or saturation. In some embodiments, the aggressive gas separation process may include contacting a gas stream at supercritical conditions with a CMS membrane to separate at least first and second gas components. The process may be useful for, among other things, the separation of CO.sub.2 from a natural gas stream.

Disclosed herein are carbon molecular sieves and methods of making the same through the pyrolysis of a polymer precursor in the presence of a reactive gas stream including a hydrogen source.

The present invention provides a carbon membrane for fluid separation that can suppress the breakage of a carbon membrane installed in a separation module during a vacuum desorption step before permeation of a fluid or during permeation of a fluid. The present invention provides a carbon membrane for fluid separation including a porous carbon support and a dense carbon layer provided on the porous carbon support, wherein the porous carbon support has an R.sub.s value of 1.0 or less, where the R.sub.s value is an R value (peak intensity of D-band (1360 cm.sup.1)/peak intensity of G-band (1580 cm.sup.1)) calculated from a Raman spectrum.

The present invention discloses high selectivity copolyimide membranes for gas, vapor, and liquid separations. Gas permeation tests on these copolyimide membranes demonstrated that they not only showed high selectivity for CO.sub.2/CH.sub.4 separation, but also showed extremely high selectivities for H.sub.2/CH.sub.4 and He/CH.sub.4 separations. These copolyimide membranes can be used for a wide range of gas, vapor, and liquid separations such as separations of CO.sub.2/CH.sub.4, He/CH.sub.4, CO.sub.2/N.sub.2, olefin/paraffin separations (e.g. propylene/propane separation), H.sub.2/CH.sub.4, He/CH.sub.4, O.sub.2/N.sub.2, iso/normal paraffins, polar molecules such as H.sub.2O, H.sub.2S, and NH.sub.3 mixtures with CH.sub.4, N.sub.2, H.sub.2. The high selectivity copolyimide membranes have UV cross-linkable sulfonyl functional groups and can be used for the preparation of UV cross-linked high selectivity copolyimide membranes with enhanced selectivities. The invention also includes blend polymer membranes comprising the high selectivity copolyimide and polyethersulfone. The blend polymer membranes comprising the high selectivity copolyimide and polyethersulfone can be further UV cross-linked under UV radiation.

An asymmetric polyvinylidene chloride copolymer membrane is made by a method using a dope solution comprised of a polyvinylidene chloride copolymer and a solvent that solubilizes the polyvinylidene chloride copolymer that is shaped to form an initial shaped membrane. The initial shaped membrane is then quenched in a liquid comprised of a solvent that is miscible with the solvent that solubilizes the polyvinylidene chloride copolymer but is immiscible with the polyvinylidene chloride copolymer to form a wet asymmetric polyvinylidene chloride copolymer membrane. The solvents are removed from the wet membrane to form the asymmetric polyvinylidene chloride (PVDC) copolymer membrane. The membrane then may be further heated to form a carbon asymmetric membrane in which the porous support structure and separation layer of the PVDC membrane is maintained. The asymmetric carbon membrane may be useful to separate gases such as olefins from their corresponding paraffins, hydrogen from syngas or cracked gas, natural gas or refinery gas, oxygen/nitrogen, or carbon dioxide and methane.