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AssigneeSociete des Ceramiques Techniques
InventorsRaymond Soria, Philippe Chanaud
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The invention is directed to a method for preparing a membrane comprising a homogeneous porous carrier, on which a layer of a molecular sieve is deposited, comprising the following steps (i) preparing an inert solution and a precursor solution of the molecular sieve; (ii) impregnating the porosity of the carrier with the inert solution and/or the precursor solution; (iii) bringing the region of the ceramic carrier intended to receive the layer of a molecular sieve into contact with the precursor solution, and bringing the region of the carrier not intended to receive the layer of a molecular sieve into contact with the inert solution; and (iv) forming a molecular sieve in situ. The invention applies e.g., to filtration or gas or liquid fluid separation, reverse osmosis or catalysis.
A method for preparing a membrane comprising a homogeneous porous carrier having a pore diameter comprised between 5 nm and 20 μm, on which a layer of a molecular sieve is deposited, comprising the following steps:
A method for preparing a membrane comprising a homogeneous porous ceramic fiber having a pore diameter comprised between 5 nm and 10 μm, on which a single zero-defect unitary layer of a zeolite is deposited, said layer having no break in its macroscopic three-dimensional structure and said layer having a thickness comprised between 3 and 50 μm, comprising the following steps:
Dependencies are inferred from the claim text.
No related US applications are recorded in the indexed filing history.
Inorganic membrane manufacture: by controlled crystallisation, e,.g. hydrothermal growth
By diffusion: characterised by specific membranes
Supported membranes; Membrane supports: support pretreatment
Molecular sieves: zeolites
Term ended 2 Dec 2019 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to a novel process for preparing a membrane comprising a porous carrier and a layer of a molecular sieve, as well as to novel membranes. The invention applies to filtration or gas or liquid fluid separation, pervaporation, reverse osmosis or catalysis.
Zeolite membranes constituted by a (macro)porous portion and a zeolite are already known. These materials can be obtained principally by two methods: a method employing a gel and a method employing a (colloidal or oligomeric) solution, such methods comprising several steps. First, a film (gel method) or total impregnation (solution method) is formed, such film or total impregnation containing species able to form a zeolite, following which the zeolite is crystallized under hydrothermal conditions.
These two types of process suffer from major drawbacks.
An aqueous solution was prepared by mixing 60 g silica of the Aerosil 380 type from Degussa with 1000 ml of tetrapropyl ammonium hydroxide (TPAOH) molar solution. The solution was left to stand overnight. The porosity of the fiber was impregnated with the distilled water and the channel was filled with the silica solution. The fiber was placed in a PTFE glove finger of 1 cm diameter filled with distilled water, and the whole thing was placed in an autoclave; hydrothermal synthesis was carried out at 180° C. over 3 days. The fiber was then rinsed and then calcined at 500° C. for 5 hours.
The mass of zeolite deposited was 20 mg equivalent to a yield of 80% with respect to the mass of silica. Microscopic observation showed a layer deposited on the inner surface of the channels which was continuous and homogeneous the thickness of which was about 4 μm, the layer being infiltrated down to about 2 μm into the fiber.
The nitrogen permeability of this membrane was 4 Nm3/h.m2.bar.