The present disclosure relates to an RHO-type zeolite comprising caesium and M.sup.1 .sub.wherein M.sup.1 is selected from Na and/or Li remarkable in that it has a Si/Al molar ratio comprised between 1.2 and 3.0 as determined by .sup.29Si magic angle spinning nuclear magnetic resonance, in that the RHO-type zeolite has a specific surface area comprised between 40 m.sup.2g.sup.−1 and 250 m.sup.2g.sup.−1 as determined by N.sub.2 adsorption measurements, in that the RHO-type zeolite being in the form of one or more nanoparticles with an average crystal size comprised between 10 nm and 400 nm as determined by scanning electron microscopy wherein said nanoparticles form monodispersed nanocrystals or form aggregates of nanocrystals having an average size ranging from 100 nm to 500 nm, as determined by scanning electron microscopy. Amorphous precursors, devoid of an organic structure-directing agent, as well as a method for preparation of these amorphous precursors in the absence of such organic structure-directing agent and method for preparation of the RHO-type zeolites, are alos described. Finally, the use of the RHO-type zeolite as a sorbent for carbon dioxide is also demonstrated.

The present disclosure relates to a chabazite-type zeolite, comprising at least two cages composed of 4- and 8-membered rings connected by one 6-membered double ring, remarkable in that it has a Si/Al molar ratio comprised between 1 and 15, in that it comprises caesium and potassium with a Cs/K molar ratio of at most 5.0 and in that it forms nanoparticles with an average crystal size comprised between 5 nm and 250 nm and with a specific surface area comprised between 50 m.sup.2g.sup.−1 and 200 m.sup.2g.sup.−1. Amorphous precursors, devoid of an organic structure-directing agent, as well as a method for preparation of these amorphous precursors in the absence of such organic structure-directing agent and method for preparation of the chabazite-type zeolite, are also described. Finally, the use of the chabazite-type zeolite as a sorbent for carbon dioxide is also demonstrated.

The present disclosure is directed to Low Temperature NOx-Absorber (LT-NA) catalyst compositions, catalyst articles, and an emission treatment system for treating an exhaust gas, each including the LT-NA catalyst compositions. Further provided are methods for reducing a NO.sub.x level in an exhaust gas stream using the catalyst article. In particular, the LT-NA compositions include a zeolite containing a first metal component including palladium and a second metal component which is an alkaline earth metal component, an oxide of an alkaline earth metal component, a rare earth metal component, an oxide of a rare earth metal component, or a combination thereof. The LT-NA compositions exhibit increased low temperature NO.sub.x adsorption capacity and enhanced hydrothermal stability.

The present disclosure is directed to metal ion-containing zeolitic compositions, preferably transition metal ion-containing, more preferably zinc ion containing zeolitic compositions, that are useful for reversibly scavenging water from humid gaseous feed streams, including air, and method of making and using the same. In some embodiments, the compositions comprise zinc-ion-doped zeolites have LTA, FAU, or EMT topologies.

Disclosed are processes and systems for the removal of water from a feed stream utilizing swing adsorption processes including an adsorbent bed comprising an adsorbent material which is a cationic zeolite RHO. The cationic zeolite RHO comprises at least one, preferably two, metal cations selected from Group 1 and 2 elements (new Group 1-18 IUPAC numbering). The swing adsorption processes and systems utilizing the cationic zeolite RHO have an adsorption selectivity for water and are useful in selective dehydration of commercial feed streams. The cationic zeolite RHO additionally has an exceptionally high water adsorption stability for use in feed streams with wet acid gas environments operating under cyclic swing adsorption conditions.

The present disclosure is directed to metal ion-containing zeolitic compositions, preferably transition metal ion-containing, more preferably zinc ion containing zeolitic compositions, that are useful for scavenging CO.sub.2 from low-CO.sub.2-content feed streams, including air, and method of making and using the same. In some embodiments, the compositions comprise zinc-ion-doped zeolites having AEI, AFX, or CHA topologies.

An adsorbent vessel for removing contaminants from a feed gas upstream from a cryogenic distillation process using pressure swing adsorption, temperature swing adsorption, or thermal-pressure swing adsorption. The adsorbent vessel having an adsorbent bed comprised of multiple layers of adsorbent material, including two layers of adsorbent material that selective adsorbs carbon dioxide. Each of the two layers is formed from an adsorbent material having a different capacity for adsorbing carbon dioxide.

A sorbent suitable for sorbing aldehydes includes acidified zeolite impregnated with a urea-based compound, the acidified zeolite having a pore opening of 5 Å or greater and a molar ratio of silicate to aluminate of at least 1.1:1. The sorbent may be prepared by impregnating acidified zeolite with a solution of a urea-based compound, where the acidified zeolite includes proton counterions. The sorbent may be supported on a filter support to provide an air filter.

An adsorbent vessel for removing contaminants from a feed gas upstream from a cryogenic distillation process using pressure swing adsorption, temperature swing adsorption, or thermal-pressure swing adsorption. The adsorbent vessel having an adsorbent bed comprised of multiple layers of adsorbent material, including two layers of adsorbent material that selective adsorbs carbon dioxide. Each of the two layers is formed from an adsorbent material having a different capacity for adsorbing carbon dioxide.

The present invention relates to a method of fabricating an organic structure directing agent-free CHA type zeolite membrane and a membrane fabricated thereby, and more particularly to a method of fabricating a continuous CHA type zeolite membrane, which exhibits CO.sub.2/N.sub.2 and CO.sub.2/CH.sub.4 separation performances comparable with those of conventional membranes, in a cost-effective manner without a calcination process by hydrothermal synthesis using an alkali metal hydroxide without using an organic structure directing agent, and to a membrane fabricated thereby.