Membrane production method
A method for producing membranes which contain at least one solid layer on one side of a porous substrate by treating the side of the support, which is to be coated, with a synthetic solution that forms the solid layer. The inventive method is characterized in that the space located behind the side of the porous support, which is not to be coated, is filled with an inert fluid during the production of the solid layer on the porous support, “behind” being from the perspective of the support. The pressure and/or the temperature of the fluid is/are selected such that the synthetic solution is essentially prevented from entering in contact with the side of the porous support, which is not to be coated.
1. A process for the production of membranes, which contain at least one solid layer on one side of a porous substrate, which comprises treating,
with synthesis solution forming the solid layer,
that side of the substrate which is to be coated,
wherein, in the production of the solid layer on the porous substrate, the substrate itself is partly or completely filled with an inert fluid and
the space which is in contact with that side of the porous substrate which is not to be coated is filled with an inert fluid,
the pressure and/or the temperature of the fluid being chosen so that contact of the synthesis solution with that side of the porous substrate which is not to be coated is substantially prevented,
wherein the fluid is gaseous, and
wherein the pressure of the fluid during the production of the solid layer is kept at a value which corresponds to the solution where the contact angle formed by the synthesis solution and
substrate material is less than 90° or wherein the pressure of the fluid during the production of the solid layer is kept at a value which corresponds to not more than the pressure of the synthesis solution where the contact angle made by synthesis solution and substrate material is greater than 90° and
wherein the inert fluid is nitrogen and wherein the space filled with the synthesis solution is sealed from the space filled with the fluid.
2. The process according to claim 1 , wherein the substrate contains material which is selected from the group consisting of aluminum oxide, titanium oxide, zirconium oxide, magnesium oxide, metal and carbon.
3. The process according to claim 1 , wherein the layer consists of a crystalline material which is selected from the group consisting of zeolites and mixed-conductivity oxides having a perovskite structure.
4. The process according to claim 1 , wherein the layer consists of an amorphous material which is metal oxides.
5. The process according to claim 2 , wherein the layer consists of a crystalline material which is selected from the group consisting of zeolites and mixed-conductivity oxides having a perovskite structure.
6. A process according to claim 5 , wherein the layer consists of an amorphous material which is metal oxides.