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 2θ indicating a maximum peak in a range of diffraction angle 2θ 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.

A feed containing methane and nitrogen gas is processed in a three-stage membrane system, each stage of which is selective for methane over nitrogen. The methane enriched permeate from the first stage is removed as product gas. The methane-depleted residue from the second stage is purified in second and third cascaded stages to provide second and third permeates and second and third residues. The third stage permeate is recycled to the feed.

This invention relates to a dispersion comprising porous particles dispersed in a liquid phase, wherein the porous particles comprise a zeolite and the liquid phase is a size-excluded liquid. The invention also relates to a method of adsorbing a gas into a liquid, comprising at least the step of bringing the gas into contact with the dispersion. In addition, the invention relates to an assemblage of the dispersion, the zeolite comprising a cavity and a gas contained within the cavity.

A method for producing a gas separation membrane includes a step of leaving a dispersion liquid to stand still, the dispersion liquid being obtained by mixing zeolite microcrystalline bodies formed from MFI zeolite and graphene oxide with pure water, and covering the periphery of the zeolite microcrystalline bodies with the graphene oxide; a step of drying the dispersion liquid after being left to stand to obtain a powder; a step of subjecting the powder to a reduction treatment of the graphene oxide by means of heating; and a step of pressure-forming the powder after the reduction treatment so as to be formed into a membrane form.

New carbon nanomaterials, preferably titanium carbide-derived carbon (CDC) nanoparticles, were embedded into a polyamide film to give CDC/polyamide mixed matrix membranes by the interfacial polymerization reaction of an aliphatic diamine, e.g., piperazine, and an activated aromatic dicarboxylate, e.g., isophthaloyl chloride, supported on a sulfone-containing polymer, e.g., polysulfone (PSF), layer, which is preferably previously prepared by dry/wet phase inversion. The inventive membranes can separate CO.sub.2 (or other gases) from mixtures of CO.sub.2 and further gases, esp. CH.sub.4, based upon the generally selective nanocomposite layer(s) of CDC/polyamide.

An aminated siliceous adsorbent, which is the reaction product of dried acidified rice husk ash having disordered mesopores and an amino silane, wherein amine functional groups are present on an external surface and within the mesopores of the dried acidified rice husk ash, and wherein the aminated siliceous adsorbent has a carbon content of 24 to 30 wt. %, based on a total weight of the aminated siliceous adsorbent. A method of making the aminated siliceous adsorbent and a method of capturing CO.sub.2 from a gas mixture with the aminated siliceous adsorbent.

Primary, secondary (1°,2°) alkylethylenediamine- and alkylpropylenediamine-appended variants of metal-organic framework are provided for CO.sub.2 capture applications. Increasing the size of the alkyl group on the secondary amine enhances the stability to diamine volatilization from the metal sites. Two-step adsorption/desorption profiles are overcome by minimzing steric interactions between adjacent ammonium carbamate chains. For instance, the isoreticularly expanded framework Mg.sub.2(dotpdc) (dotpdc.sup.4−=4,4″-dioxido-[1,1′:4′,1″-terphenyl]-3,3″-dicarboxylate), yields diamine-appended adsorbents displaying a single CO.sub.2 adsorption step. Further, use of the isomeric framework Mg-IRMOF-74-II or Mg.sub.2(pc-dobpdc) (pc-dobpdc.sup.4−=3,3-dioxidobiphenyl-4,4-dicarboxylate, pc=para-carboxylate) also leads to a single CO.sub.2 adsorption step with bulky diamines. By relieving steric interactions between adjacent ammonium carbamate chains, these frameworks enable step-shaped CO.sub.2 adsorption, decreased water co-adsorption, and increased stability to diamine loss. Variants of Mg.sub.2(dotpdc) and Mg.sub.2(pc-dobpdc) functionalized with large diamines such as N-(n-heptyl)ethylenediamine have utility as adsorbents for carbon capture applications.

It is provided a water-saturated carbon molecular sieve membrane obtainable by a) providing a hydrophilic carbon molecular sieve membrane (CMSM) comprising pores of a pore size from 0.25 nm to 0.55 nm for molecular sieving, pores of a pore size from 0.55 nm to 0.90 nm for adsorption diffusion and a negligible amount of pores larger than 0.90 nm such that a plot of N.sub.2 permeance versus pressure of permeation at room temperature and at a pressure from 1 to 4 bar has zero or negative slope; and b) humidifying the membrane until obtaining a water-saturated carbon molecular sieve membrane. It is also provided a process for the separation of a gas from a gas mixture with such a water-saturated membrane, and its use for solvent dehydration, and as a membrane reactor.

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).

A system and method for removing hydrogen sulfide from natural gas using a triazine scavenger is described. The system includes a pre-treatment system that can be connected to an existing hydrogen sulfide removal system to more fully utilize the triazine scavenger. The pre-treatment system includes a contactor vessel in which sour natural gas is contacted with fresh and/or partially consumed scavenger to partially sweeten the sour gas by removing H.sub.2S. The partially sweetened gas then flows to the existing hydrogen sulfide removal system where it is fully sweetened.