Method for preparing support of molecular sieve membrane

A method for preparing a support of a molecular sieve membrane, comprising steps of:

• (1) adding ethyl alcohol and a first weight of water into a reaction kettle, then adding cordierite powders, and uniformly stirring;
• adding a first dispersant, then adding tetraethoxysilane, aluminum salt, magnesium salt and lanthanum salt, stirring and dissolving, and obtaining a mixed liquid;
• increasing a temperature of the mixed liquid to 65-80° C., then adding ammonium hydroxide into the mixed liquid, and adjusting a pH value thereof to 5-6;
• reacting for 2-12 hours, and generating a mixed sol of silicon, aluminum, magnesium and lanthanum, wherein a proportion of silicon, aluminum and magnesium in the mixed sol is the same as that in a composition of cordierite;
• further adjusting the pH value to 8-9, reacting for 2-6 hours, and aging the mixed sol;
• pouring an obtained mixture into a container, standing and generating precipitates;
• washing the precipitates with reverse osmosis (RO) water, sucking and filtering liquid out, and drying the precipitates;
• heating the dried precipitates, keeping a temperature of the precipitates, and obtaining cordierite particles enveloped by composite nanometer oxides which are prepared according to a composition proportion of the cordierite;
• (2) uniformly mixing and stirring the cordierite particles, a binder, a second weight of water and a humectant, and forming mud;
• preparing the mud into a green body, drying the green body, and sintering the green body into a cordierite support;
• and
• (3) adding zirconia into a third weight of water, adjusting a pH value thereof to 2.5-3 with nitric acid, and uniformly stirring;
• then adding a second dispersant and a viscosity modifier, uniformly stirring, and obtaining a film coating solution;
• coating the film coating solution on an outer layer of the cordierite support, drying and sintering the cordierite support, and obtaining the cordierite support with the outer layer coated by a zirconia film layer.