The present invention concerns the use, for gas separation and/or gas drying, of at least one zeolite adsorbent material comprising at least one type A zeolite, said adsorbent having an external surface area greater than 20 m.sup.2.Math.g.sup.1, a non-zeolite phase (PNZ) content such that 0<PNZ30%, and an Si/Al atomic ratio of between 1.0 and 2.0. The invention also concerns a zeolite adsorbent material having an Si/Al ratio of between 1.0 and 2.0, a mesoporous volume of between 0.07 cm.sup.3.Math.g.sup.1 and 0.18 cm.sup.3.Math.g.sup.1, a (VmicroVmeso)/Vmicro ratio of between 3 and 1.0, non-inclusive, and a non-zeolite phase (PNZ) content such that 0<PNZ30%.

A process for preparing a zeolitic material containing YO.sub.2 and X.sub.2O.sub.3, where Y and X represent a tetravalent element and a trivalent element, respectively, is described. The process includes (1) a step of preparing a mixture containing one or more structure directing agents, seed crystals, and a first zeolitic material containing YO.sub.2 and X.sub.2O.sub.3 and having FAU-, GIS-, MOR-, and/or LTA-type framework structures; and (2) a step of heating the mixture for obtaining a second zeolitic material containing YO.sub.2 and X.sub.2O.sub.3 and having a different framework structure than the first zeolitic material. The mixture prepared in (1) and heated in (2) contains 1000 wt % or less of H.sub.2O based on 100 wt % of YO.sub.2 in the framework structure of the first zeolitic material. A zeolitic material obtainable and/or obtained by the process and its use are also described.

The present invention relates to a hydrocarbon adsorbent with metal-impregnated zeolite particles having regular mesopores and a manufacturing method therefor. The hydrocarbon adsorbent includes a metal cation and a metal oxide that are impregnated in zeolite particles, in particular, the zeolite particles include regularly formed mesopores having a size of 2 to 10. By adjusting a Si/Al ratio and mesoporosity of the mesopores, a hydrocarbon adsorbent may have increased adsorption capacity for hydrocarbons in a cold-start section and can rapidly oxidize the hydrocarbon upon desorption thereof, thereby reducing the discharge of exhaust gas produced in automobiles and industries.

Described is a selective catalytic reduction catalyst comprising a zeolitic framework material of silicon and aluminum atoms, wherein a fraction of the silicon atoms are isomorphously substituted with a tetravalent metal. The catalyst can include a promoter metal such that the catalyst effectively promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H.sub.2O selectively over a temperature range of 150 to 650 C. In another aspect, described is a selective catalytic reduction composite comprising an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation state of IV. The SCR catalyst material promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H.sub.2O selectively over a temperature range of 150 C. to 600 C., and the SCR catalyst material is effective to store ammonia at temperatures of 400 C. and above. A method for selectively reducing nitrogen oxides, and a method for simultaneously selectively reducing nitrogen oxide and storing ammonia are also described. Additionally, an exhaust gas treatment system is also described.

The present invention relates to a superior carbon adsorbent with or without a core. In one embodiment the carbon adsorbent of the present invention employs carbon adsorbent powder and an organic binding agent which are combined together with an appropriate solvent in an agglomeration step. In another embodiment the invention contemplates a core-in-shell adsorbent comprising an outer shell composed of a carbon and a non-adsorbing inert inner core. Low temperature processing of these agglomerates substantially preserves the binding agent within the final composition and allows one to prepare adsorbent products of high sphericity. The adsorbents of the invention possess superior characteristics such as higher mass transfer rate and CO.sub.2 working capacity for use in a H.sub.2PSA process.

Methods, compositions, systems and devices are provided in which zeolite particles, preferably of silicon and aluminum, are used as desiccants. In embodiments a plurality of zeolite particles are provided that are less than 1 mm in size. The particles may be arrayed such that at least some of the plurality of particles are spaced apart from each other and may be arrayed in rows and columns. Embodiments provide the particles are useful or removing water under ambient conditions and in removing water from air or material and in an embodiment removing water from plant material, such as harvested crop material, or where the dried air is contacted with plant material. Microwave radiation may be used to efficiently and in a cost effective manner dehydrate the rehydrated particles.

A hydrocarbon adsorbent, according to one embodiment of the present invention, comprises a copper-containing ZSM-5 zeolite, wherein a Si/Al molar ratio of the ZSM-5 zeolite may be 11.5 to 40, and the amount of the copper included is 1 wt % to 10 wt %.

A GIS-type zeolite, having a diffraction peak of (1 0 1) at a diffraction angle 2=12.55 to 12.90 in a spectrum obtained by X-ray diffraction.

Methods of designing zeolite materials for adsorption of CO.sub.2. Zeolite materials and processes for CO.sub.2 adsorption using zeolite materials.

A hydrocarbon adsorbent, according to one embodiment of the present invention, comprises a copper-containing ZSM-5 zeolite, wherein a Si/Al molar ratio of the ZSM-5 zeolite may be 11.5 to 40, and the amount of the copper included is 1 wt % to 10 wt %.