A method for manufacturing a zeolite membrane structure comprises an immersion step for immersing a porous substrate in a synthetic sol, and a synthesis step for hydrothermally synthesizing a zeolite membrane on a surface of the porous substrate that has been immersed in the synthesis so. When the foamability of the synthetic sol is measured by a Ross-Miles method under a condition of 25 degrees C., the foam height after elapse of 5 minutes from completion of down flow is less than or equal to 5 mm.

The invention relates to a process for preparing an AFX-structure zeolite comprising at least the following steps: i) mixing, in an aqueous medium, an FAU-structure zeolite having an SiO.sub.2 (FAU)/Al.sub.2O.sub.3 (FAU) molar ratio of between 6.00 and 200, limits included, an organic nitrogenous compound R, at least one source of at least one alkali and/or alkaline-earth metal M, the reaction mixture having the following molar composition: (SiO.sub.2 (FAU))/(Al.sub.2O.sub.3 (FAU)) between 6.00 and 200, H.sub.2O/(SiO.sub.2 (FAU)) between 1.00 and 100, R/(SiO.sub.2 (FAU)) between 0.01 and 0.60, M.sub.2/nO/(SiO.sub.2 (FAU)) between 0.005 and 0.45, limits included, until a homogeneous precursor gel is obtained; ii) hydrothermal treatment of said precursor gel obtained on conclusion of step i) at a temperature of between 120° C. and 220° C., for a time of between 12 hours and 15 days.

The invention relates to a process for preparing an AFX-structure zeolite comprising at least the following steps: i) mixing, in an aqueous medium, an FAU-structure zeolite having an SiO.sub.2 (FAU)/Al.sub.2O.sub.3 (FAU) molar ratio of between 6.00 and 200, limits included, an organic nitrogenous compound R, at least one source of at least one alkali and/or alkaline-earth metal M, the reaction mixture having the following molar composition: (SiO.sub.2 (FAU))/(Al.sub.2O.sub.3 (FAU)) between 6.00 and 200, H.sub.2O/(SiO.sub.2 (FAU)) between 1.00 and 100, R/(SiO.sub.2 (FAU)) between 0.01 and 0.60, M.sub.2/nO/(SiO.sub.2 (FAU)) between 0.005 and 0.45, limits included, until a homogeneous precursor gel is obtained; ii) hydrothermal treatment of said precursor gel obtained on conclusion of step i) at a temperature of between 120° C. and 220° C., for a time of between 12 hours and 15 days.

A small-pore zeolite that is modified with phosphorus, is excellent in hydrothermal durability, and has an 8-membered oxygen ring structure. The 8-membered oxygen ring structure is CHA, AEI, and AFX. The small-pore zeolite incudes at least an aluminum element, a silica element, a phosphorus element, wherein the phosphorus element is defined by expression (1), and the small-pore zeolite has an 8-membered oxygen ring structure being of CHA, AEI, or AFX. The phosphorus element that modifies the zeolite is unevenly distributed and richly contained on the surface layer side of the zeolite. A method for producing a phosphorus element-containing zeolite.

Provided is at least one of a CHA-type zeolite having a greater amount of a paired aluminum structure than do CHA-type zeolites of the related art; a catalyst containing the CHA-type zeolite; and a method for producing these. A method for producing a CHA-type zeolite includes crystallizing a composition that contains an alumina source, a silica-alumina source, an alkali source, an organic structure-directing agent and water. Preferably, the composition is prepared by mixing the alumina source, the alkali source, the organic structure-directing agent and the water together and subsequently mixing the silica-alumina source therewith.

The present disclosure is directed to microporous crystalline aluminosilicate structures with GME topologies having pores containing organic structure directing agents (OSDAs) comprising at least one piperidinium cation, the compositions useful for making these structures, and methods of using these structures. In some embodiments, the crystalline zeolite structures have a molar ratio of Si:Al that is greater than 3.5.

The present disclosure is directed to microporous crystalline aluminosilicate structures with GME topologies having pores containing organic structure directing agents (OSDAs) comprising at least one piperidinium cation, the compositions useful for making these structures, and methods of using these structures. In some embodiments, the crystalline zeolite structures have a molar ratio of Si:Al that is greater than 3.5.

The invention relates to a catalyst comprising a mixture of AFX-structure and BEA-structure zeolites and at least one additional transition metal, to the process for preparing same and to the use thereof for the selective catalytic reduction of NOx in the presence of a reducing agent such as NH.sub.3 or H.sub.2.

The present invention relates to a process for the calcination of a zeolitic material, wherein said process comprises the steps of (i) providing a zeolitic material comprising YO.sub.2 and optionally further comprising X.sub.2O.sub.3 in its framework structure in the form of a powder and/or of a suspension of the zeolitic material in a liquid, wherein Y stands for a tetravalent element and X stands for a trivalent element; (ii) atomization of the powder and/or of the suspension of the zeolitic material provided in (i) in a gas stream for obtaining an aerosol; (iii) calcination of the aerosol obtained in (ii) for obtaining a calcined powder; as well as to a zeolitic material obtainable and/or obtained according the inventive process, and to its use as a molecular sieve, as an adsorbent, for ion-exchange, as a catalyst, and/or as a catalyst support.

The present invention relates to a process for the calcination of a zeolitic material, wherein said process comprises the steps of (i) providing a zeolitic material comprising YO.sub.2 and optionally further comprising X.sub.2O.sub.3 in its framework structure in the form of a powder and/or of a suspension of the zeolitic material in a liquid, wherein Y stands for a tetravalent element and X stands for a trivalent element; (ii) atomization of the powder and/or of the suspension of the zeolitic material provided in (i) in a gas stream for obtaining an aerosol; (iii) calcination of the aerosol obtained in (ii) for obtaining a calcined powder; as well as to a zeolitic material obtainable and/or obtained according the inventive process, and to its use as a molecular sieve, as an adsorbent, for ion-exchange, as a catalyst, and/or as a catalyst support.