CN-121992389-A - Preparation process for eliminating performance difference of two sides of MFI zeolite membrane of aluminum alloy matrix

Abstract

The invention relates to the technical field of metal anti-corrosion coatings, in particular to a preparation process for eliminating performance difference of two sides of an MFI zeolite membrane of an aluminum alloy matrix, which comprises the following steps of preparing an MFI zeolite membrane synthetic mother solution by using sodium hydroxide, deionized water, tetraethoxysilane and tetrapropylammonium hydroxide; the method comprises the steps of carrying out surface treatment on an aluminum alloy matrix, placing the aluminum alloy matrix in a reaction kettle containing mother liquor, wherein the aluminum alloy matrix is not in direct contact with the mother liquor initially, placing the reaction kettle in an oven for reaction, inverting the reaction kettle to enable the surface of the aluminum alloy matrix to be in uniform contact with the mother liquor and continuously reacting, and finally forming the MFI zeolite membrane with consistent two-sided performance. According to the invention, the reaction kettle is heated to form a uniform temperature field and a fluid field and then inverted, so that the aluminum alloy is in uniform contact with the reaction liquid containing the primary crystal nucleus, the 'different surface' effect caused by uneven temperature field, concentration field and convection in the reaction kettle in the in-situ hydrothermal synthesis is effectively eliminated, and a foundation is laid for large-scale industrial application from laboratory research.

Inventors

• TONG XIAOQIANG
• YANG LIJIE
• ZHANG ZONGWEI

Assignees

• 中国民航大学

Dates

Publication Date

20260508

Application Date

20251015

Claims (5)

1. 1. A preparation process for eliminating performance difference of two sides of an MFI zeolite membrane with an aluminum alloy matrix is characterized by comprising the following steps: s1, preparing mother liquor, namely preparing MFI zeolite membrane synthesis mother liquor by taking sodium hydroxide, deionized water, tetraethoxysilane and tetrapropylammonium hydroxide; S2, surface treatment, namely performing surface treatment on the aluminum alloy matrix to remove surface stains and foreign matters; s3, preparing the MFI zeolite membrane with consistent two-sided performance, namely placing the aluminum alloy matrix in the step S2 into a reaction kettle containing the mother liquor in the step S1, wherein the aluminum alloy matrix is not in direct contact with the mother liquor initially; Putting the reaction kettle into a baking oven, reaching a target temperature and reacting at constant temperature; And inverting the reaction kettle to ensure that the surface of the aluminum alloy matrix is in uniform contact with the mother solution and continuously reacts, and finally forming the MFI zeolite membrane with consistent two-sided performance on the surface of the aluminum alloy matrix.
2. 2. The process for preparing an MFI zeolite membrane with aluminum alloy matrix according to claim 1, wherein the molar ratio of sodium hydroxide, tetrapropylammonium hydroxide, ethyl orthosilicate to deionized water in step S1 is 0.64:0.16:1:92-100; the preparation process of the mother solution specifically comprises the following steps: Firstly, mixing sodium hydroxide and deionized water, and placing the mixture on a magnetic stirrer for stirring, wherein the stirring intensity is 200-300r/min; after the sodium hydroxide is completely dissolved, adding tetrapropylammonium hydroxide and continuing stirring for 5min; then dropwise adding ethyl orthosilicate to prevent the ethyl orthosilicate from being directly condensed; continuously stirring and aging for 6-24 hours to obtain the mother liquor.
3. 3. The process for preparing the MFI zeolite membrane with no difference in performance of the two surfaces of the aluminum alloy matrix according to claim 1, wherein the surface treatment of the aluminum alloy matrix in the step S2 comprises the following steps: vertically placing the aluminum alloy substrates in a clean beaker to ensure that a plurality of aluminum alloy substrates are not overlapped with each other; Adding absolute ethyl alcohol into the beaker, so that the liquid level of the absolute ethyl alcohol completely submerges the top of the aluminum alloy matrix; and placing the beaker into an ultrasonic cleaner, and performing ultrasonic treatment for 5-10 min to finish the surface treatment of the aluminum alloy matrix.
4. 4. The process for preparing the MFI zeolite membrane with no difference in performance of the two surfaces of the aluminum alloy matrix according to claim 1, wherein the step S3 is characterized in that the aluminum alloy matrix is not directly contacted with the mother liquor: The aluminum alloy matrix is separated from the mother solution by the support body immersed in the mother solution, so that uneven nucleation caused by heat conduction or uneven flow field on two sides of the aluminum alloy matrix in the heating process is avoided; the support body is polytetrafluoroethylene, and the length of the polytetrafluoroethylene support body is slightly longer than that of the aluminum alloy matrix, so that the aluminum alloy matrix is ensured to be stably erected on the support body and is not contacted with the inner wall of the reaction kettle and the mother liquor.
5. 5. The preparation process for eliminating the performance difference of the two surfaces of the MFI zeolite membrane of the aluminum alloy matrix according to claim 1, wherein the target temperature in the step S3 is 175 ℃, the constant temperature reaction time is 0-4h, and the uniform contact reaction time of the surface of the aluminum alloy matrix and the mother liquor is 10-14 h.

Description

Preparation process for eliminating performance difference of two sides of MFI zeolite membrane of aluminum alloy matrix Technical Field The invention relates to the technical field of metal anti-corrosion coatings, in particular to a preparation process for eliminating performance difference of two sides of an MFI zeolite membrane of an aluminum alloy matrix. Background The aluminum-based MFI type zeolite membrane has excellent chemical stability, corrosion resistance and structural controllability, and has great application potential in the field of metal surface corrosion prevention. At present, an in-situ hydrothermal synthesis method is a mainstream technology for preparing the film, has the advantages of simple process flow, low equipment requirement, controllable production cost and the like, and has the basis of large-scale popularization. However, when the conventional in-situ hydrothermal synthesis method is used for preparing the flat-plate-shaped aluminum alloy substrate, the problem of a remarkable product 'different-surface' effect is caused, and the problem is often expressed that one surface of the film layer is continuously compact, the other surface of the film layer is loose, not compact or even has no film, so that the corrosion resistance of the two surfaces of the substrate is unbalanced, the reliability of the product is seriously reduced, and the method becomes a key technical bottleneck for restricting the aluminum-based MFI zeolite film from the laboratory research to large-scale industrial application. Disclosure of Invention The invention aims to provide a preparation process for eliminating the performance difference of two sides of an aluminum alloy matrix MFI zeolite membrane, so as to solve the problem that a product has a continuous compact membrane layer and a loose, non-compact or even no membrane layer, so that the corrosion resistance of two sides of the matrix is unbalanced, the reliability of the product is seriously reduced, and the problem becomes a key technical bottleneck for restricting the development of the aluminum matrix MFI zeolite membrane from laboratory researches to large-scale industrial application. In order to achieve the aim, the invention provides the following technical scheme that the preparation process for eliminating the performance difference of the two sides of the MFI zeolite membrane with the aluminum alloy matrix comprises the following steps: s1, preparing mother liquor, namely preparing MFI zeolite membrane synthesis mother liquor by taking sodium hydroxide, deionized water, tetraethoxysilane and tetrapropylammonium hydroxide; S2, surface treatment, namely performing surface treatment on the aluminum alloy matrix to remove surface stains and foreign matters; s3, preparing the MFI zeolite membrane with consistent two-sided performance, namely placing the aluminum alloy matrix in the step S2 into a reaction kettle containing the mother liquor in the step S1, wherein the aluminum alloy matrix is not in direct contact with the mother liquor initially; Putting the reaction kettle into a baking oven, reaching a target temperature and reacting at constant temperature; And inverting the reaction kettle to ensure that the surface of the aluminum alloy matrix is in uniform contact with the mother solution and continuously reacts, and finally forming the MFI zeolite membrane with consistent two-sided performance on the surface of the aluminum alloy matrix. Preferably, in the step S1, the molar ratio of the sodium hydroxide to the tetrapropylammonium hydroxide to the tetraethyl orthosilicate to the deionized water is 0.64:0.16:1:92-100; the preparation process of the mother solution specifically comprises the following steps: Firstly, mixing sodium hydroxide and deionized water, and placing the mixture on a magnetic stirrer for stirring, wherein the stirring intensity is 200-300r/min; after the sodium hydroxide is completely dissolved, adding tetrapropylammonium hydroxide and continuing stirring for 5min; then dropwise adding ethyl orthosilicate to prevent the ethyl orthosilicate from being directly condensed; continuously stirring and aging for 6-24 hours to obtain the mother liquor. Preferably, the surface treatment process for the aluminum alloy substrate in the step S2 specifically includes: vertically placing the aluminum alloy substrates in a clean beaker to ensure that a plurality of aluminum alloy substrates are not overlapped with each other; Adding absolute ethyl alcohol into the beaker, so that the liquid level of the absolute ethyl alcohol completely submerges the top of the aluminum alloy matrix; and placing the beaker into an ultrasonic cleaner, and performing ultrasonic treatment for 5-10 min to finish the surface treatment of the aluminum alloy matrix. Preferably, in the step S3, the aluminum alloy substrate is not directly contacted with the mother liquor at first specifically: The aluminum alloy matrix is separated from the mother s