A method for preparing a solvent-resistant organosilicon / ceramic composite film

Abstract

The present invention discloses a method for preparing a solvent-resistant organosilicon / ceramic composite membrane, comprising the following steps: preparing an acid-catalyzed organosilicon polymer sol; preparing an acid-base swing organosilicon sol; and sequentially depositing the acid-base swing organosilicon sol and the acid-catalyzed organosilicon polymer sol directly onto an anodized aluminum support using a two-step process assisted by an airflow-assisted ultrasonic atomization process. Following high-temperature post-treatment, the solvent-resistant ultra-thin organosilicon / ceramic composite membrane is produced. This composite membrane has the advantages of adjustable pore size, good mechanical strength, and chemical stability. Combining the advantages of an organosilicon separation layer and an anodized aluminum support, the composite membrane can be applied to organic solvent wastewater treatment processes.

Description

Technical Field

[0001] The invention belongs to the field of composite film preparation, and particularly relates to a method for preparing a solvent-resistant organic silicon / ceramic composite film. Background Art

[0002] Bridged silicone materials have good hydrothermal stability, chemical stability and excellent molecular sieving properties, and have attracted widespread attention as potential solvent-resistant nanofiltration membrane materials.

[0003] Currently, organosilicon composite membranes are typically prepared by coating asymmetric ceramic supports using methods such as dipping, rubbing, spin coating, and casting. While membranes prepared by dipping and casting methods have excellent integrity, their thickness is difficult to adjust and can be unevenly distributed. Rubbing and spin coating methods can produce ultra-thin separation layers, but they are prone to defects and have poor reproducibility. Currently, organosilicon composite membranes are primarily prepared using inorganic porous ceramic supports. Compared to organic polymer supports, inorganic ceramic supports offer advantages such as high mechanical and chemical stability and good compatibility.

[0004] However, the inorganic supports currently used are mostly α-Al2O3 ceramic microfiltration membranes. Due to their large pore size, the composite membrane preparation process requires multiple coatings of inorganic particle sol layers to form a transition layer, thereby reducing the effective pore size of the support and preventing serious pore permeation during the preparation of the silicone separation layer. This preparation process is cumbersome and leads to problems such as reduced porosity and membrane flux of the support layer, increased membrane mass transfer resistance, etc., making it difficult to achieve high performance of the membrane during application. Summary of the Invention

[0005] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a solvent-resistant ultra-thin organosilicon / ceramic composite film.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for preparing a solvent-resistant ultra-thin organosilicon / ceramic composite film, comprising:

[0009] The organosilicon precursor and inorganic acid are subjected to hydrolysis polymerization reaction with water in an alcohol solvent to prepare an acid-catalyzed organosilicon polymer sol;

[0010] The organosilicon precursor and inorganic acid are stirred in a constant temperature water bath with water in an alcohol solvent, an alkali catalyst is added and stirred in a constant temperature water bath, and then the inorganic acid is added and stirred in a constant temperature water bath to prepare an acid-base swing organosilicon sol;

[0011] The diluted acid-base swing organosilicon sol and the acid-catalyzed organosilicon polymer sol are sequentially deposited on a preheated anodized aluminum support and post-treated at high temperature to obtain a solvent-resistant ultra-thin organosilicon / ceramic composite film.

[0012] As a preferred embodiment of the preparation method of the present invention, the preparation method of the acid-catalyzed organosilicon polymer sol comprises:

[0013] Add the organosilicon precursor to the alcohol solvent and stir for 1 to 2 minutes;

[0014] Add deionized water dropwise and continue stirring for 1 to 2 minutes;

[0015] After adding the inorganic acid dropwise, the mixture was immediately transferred to a constant temperature water bath at 25-60°C and stirred for 2-4 hours to obtain an acid-catalyzed organosilicon polymer sol; wherein,

[0016] The molar ratio of the organosilicon precursor, deionized water and inorganic acid is 1:30-240:0.1-0.2.

[0017] As a preferred embodiment of the preparation method of the present invention, the organosilicon precursor is a silsesquioxane precursor having a carbon-hydrogen bridged structure, including 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethylene and 1,3-bis(triethoxysilyl)acetylene; the inorganic acid includes HCl; and the alcohol solvent includes n-propanol.

[0018] As a preferred embodiment of the preparation method of the present invention, the preparation method of the acid-base swing organosilica sol includes:

[0019] Add the organosilicon precursor to the alcohol solvent, stir for 1-2 minutes, then add deionized water dropwise, continue stirring for 1-2 minutes, add the inorganic acid dropwise, and immediately transfer to a constant temperature water bath at 25-60°C and continue stirring for 1-2 hours. The molar ratio of the silicon source precursor, deionized water, and inorganic acid is 1:30-240:0.1-0.2.

[0020] Add a base catalyst dropwise, and continue stirring in a constant temperature water bath at 25 to 60° C. for 30 to 90 minutes; add an inorganic acid dropwise, and continue stirring in a constant temperature water bath at 25 to 60° C. for 15 to 120 minutes to obtain an acid-base swing organosilica sol;

[0021] The molar ratio of the base catalyst to the inorganic acid is 2:1-2.

[0022] As a preferred embodiment of the preparation method of the present invention, the base catalyst includes ammonia water, sodium hydroxide and potassium hydroxide, the inorganic acid includes HCl, the alcohol solvent includes n-propanol, and the organosilicon precursor includes 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethylene and 1,3-bis(triethoxysilyl)acetylene.

[0023] As a preferred embodiment of the preparation method of the present invention, the diluted acid-base swing organosilicon sol and the acid-catalyzed organosilicon polymer sol are sequentially deposited on a preheated anodized aluminum support, wherein the concentration of the diluted sol is 1 to 5ωt%.

[0024] As a preferred solution of the preparation method of the present invention, the pore size of the anodized aluminum support is 10 to 30 nm, and the thickness is 50 μm.

[0025] As a preferred embodiment of the preparation method described in the present invention, the deposition method includes deposition through a surrounding airflow-assisted ultrasonic atomization device, wherein the carrier gas assisted by the surrounding airflow includes nitrogen and air, the ultrasonic power is 0.5-3 Hz, the liquid inlet flow rate is 0.1-2 ml / min, the single-pass spraying step is 1-5 mm, the distance between the nozzle and the support is 2-4 cm, the preheating temperature of the anodized aluminum support during deposition is 30-80°C, and a total of 2-3 spraying times.

[0026] As a preferred embodiment of the preparation method of the present invention, the high-temperature post-treatment has a treatment temperature of 100 to 300° C. and a treatment time of 10 to 30 minutes.

[0027] Another object of the present invention is to overcome the deficiencies in the prior art and provide a product obtained by a method for preparing a solvent-resistant ultra-thin organosilicon / ceramic composite film.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention utilizes surrounding airflow to assist ultrasonic atomization to spray the bridged organosilicon sol onto the anodized aluminum support, forming an ultra-thin and evenly distributed liquid film with good flux and dye retention rate, and has high performance.

[0030] (2) The present invention adopts a two-step method to spray the acid-base swing organosilicon sol and the acid-catalyzed organosilicon polymer sol on the anodized aluminum support in sequence to form a defect-free bridging organosilicon separation layer. The membrane preparation method that combines the surrounding airflow assisted ultrasonic atomization effect and the two-step method has good repeatability.

[0031] (3) The present invention selects anodized aluminum as the separation membrane support. Anodized aluminum has the advantages of solvent resistance, high temperature resistance and high flux, and has a regular porous nanostructure with a highly controllable pore size that can be adjusted from 5 nm to 10 μm. By selecting an anodized aluminum support with a pore size of 10 to 30 nm, the step of coating the transition layer is omitted, and the separation layer can be directly coated, which is simple and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0033] Figure 1 Schematic diagram of the process for preparing the solvent-resistant ultra-thin organosilicon / ceramic composite film in Example 1 of the present invention.

[0034] Figure 2 These are SEM images of the cross section and surface of the solvent-resistant ultra-thin organosilicon / ceramic composite film in Example 1 of the present invention.

[0035] Figure 3 This is an SEM image of the surface of the solvent-resistant ultra-thin organosilicon / ceramic composite film in Comparative Example 3 of the present invention.

[0036] Figure 4 This is a graph showing the long-term stability test of the solvent-resistant ultra-thin organosilicon / ceramic composite film in Example 1 of the present invention. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0040] The surrounding airflow-assisted ultrasonic atomization device in the present invention was purchased from Beijing Dongfang Jinrong Ultrasonic Electric Co., Ltd.

[0041] In the embodiment of the present invention, the pore spacing of the anodized aluminum support is 65 nm; the sheet diameter is 13 mm; the pore size is 20 nm; and the thickness is 50 μm. It was purchased from Shenzhen Topological Fine Membrane Technology.

[0042] The specific experimental conditions for the composite membrane of the present invention to be used for separation in a 100 ppm methyl orange / water solution are as follows: feed liquid temperature: 25°C; nanofiltration operating pressure: 0.4 MPa; methyl orange / water solution concentration: 100 ppm; action time: 3 h;

[0043] The flux L / (m 2 h bar) is calculated as follows: permeate volume / (membrane area × nanofiltration time × nanofiltration operating pressure);

[0044] The dye retention rate (%) is calculated as follows: (dye concentration in the raw material solution - dye concentration in the permeate solution) / dye concentration in the raw material solution.

[0045] Example 1

[0046] (1) Add 1 g of 1,2-bis(triethoxysilyl)ethane to 15.94 g of n-propanol and stir for 1 to 2 minutes. Then, dropwise add 2.78 g of deionized water. Continue stirring for 1 to 2 minutes, then dropwise add 0.278 g of 3.7% hydrochloric acid. The molar ratio of silicon source precursor, water, and hydrochloric acid is 1:60:0.1. Immediately transfer the beaker to a constant temperature water bath at 40°C and continue stirring for 2 hours to obtain a 5 wt% acid-catalyzed organosilicon polymer sol.

[0047] (2) Add 1 g of 1,2-bis(triethoxysilyl)ethane to 15.94 g of n-propanol, stir for 1 to 2 minutes, then dropwise add 2.78 g of deionized water, continue stirring for 1 to 2 minutes, then dropwise add 0.278 g of 3.7% hydrochloric acid, the molar ratio of silicon source precursor, water, and hydrochloric acid is 1:60:0.1, immediately transfer the beaker to a constant temperature water bath at 40°C and continue stirring for 1 hour, then dropwise add ammonia water, the molar ratio of ammonia water to hydrochloric acid is 2:1, continue stirring in a constant temperature water bath at 40°C for 1 hour, finally dropwise add dilute hydrochloric acid, the molar ratio of hydrochloric acid to ammonia water is 2:1, continue stirring in a constant temperature water bath at 40°C for 30 minutes, and obtain a 5 wt% acid-base swing organic silica sol;

[0048] (3) The acid-base swing organic silicon sol prepared in step (2) is diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device, and the ultrasonic controller recognizes and sets the parameter signal, sets the ultrasonic frequency to 1.0 Hz, the liquid inlet speed to 0.1 ml / min, the nozzle height to 20 mm, and the single-pass spraying step to 0.5 mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air-carrying flow rate is adjusted to 0.02 MPa, and the droplets are uniformly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature is set to 30°C, the solvent is allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 120°C for 15 minutes.

[0049] (4) The acid-catalyzed organosilicon polymer sol prepared in step (1) is diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device, and the ultrasonic controller recognizes and sets the parameter signal, sets the ultrasonic frequency to 1.0 Hz, the liquid feed rate to 0.1 ml / min, the nozzle height to 20 mm, and the single-pass spraying step to 0.5 mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air-carrying flow rate is adjusted to 0.02 MPa, and the droplets are uniformly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature is set to 30°C, the solvent is allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 120°C for 15 minutes.

[0050] (5) The prepared composite membrane was applied to a 100 ppm methyl orange / water solution for separation. A schematic diagram of the process for preparing the solvent-resistant ultra-thin organosilicon / ceramic composite membrane is shown in FIG. Figure 1 ;

[0051] See the SEM images of the cross section and surface of the solvent-resistant ultra-thin silicone / ceramic composite film. Figure 2 , it can be seen that the sol can be stacked on the anodized aluminum support to form a separation layer, and it can be seen that the thickness is 110nm and 160nm respectively.

[0052] Long-term stability test of solvent-resistant ultra-thin silicone / ceramic composite films, see Figure 4 It can be seen that the composite membrane has good stability. The test conditions are: feed liquid temperature: 25°C; nanofiltration operating pressure: 0.4MPa, and methyl orange / water solution concentration is 100ppm.

[0053] Example 2

[0054] (1) Add 1 g of 1,2-bis(triethoxysilyl)ethane to 15.94 g of n-propanol and stir for 1 to 2 minutes. Then, dropwise add 2.78 g of deionized water. Continue stirring for 1 to 2 minutes, then dropwise add 0.278 g of 3.7% hydrochloric acid. The molar ratio of silicon source precursor, water, and hydrochloric acid is 1:60:0.2. Immediately transfer the beaker to a constant temperature water bath at 60°C and continue stirring for 2 hours to obtain a 5 wt% acid-catalyzed organosilicon polymer sol.

[0055] (2) Add 1 g of 1,2-bis(triethoxysilyl)ethane to 15.94 g of n-propanol and stir for 1 to 2 minutes. Then, add 2.78 g of deionized water dropwise and continue stirring for 1 to 2 minutes. Then, add 0.278 g of 3.7% hydrochloric acid dropwise. The molar ratio of silicon source precursor, water and hydrochloric acid is 1:60:0.2. Immediately transfer the beaker to a constant temperature water bath at 60°C and continue stirring for 1 hour. Then, add ammonia water dropwise. The molar ratio of ammonia water and hydrochloric acid is 2:1. Continue stirring in a constant temperature water bath at 60°C for 1 hour. Finally, add dilute hydrochloric acid dropwise. The molar ratio of hydrochloric acid and ammonia water is 2:1. Continue stirring in a constant temperature water bath at 60°C for 30 minutes to obtain a 5 wt% acid-base swing organic silica sol.

[0056] (3) The acid-base swing organic silicon sol prepared in step (2) is diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device. The ultrasonic controller identifies and sets the parameter signal, sets the ultrasonic frequency to 1.0Hz, the liquid inlet speed to 0.1ml / min, the nozzle height to 20mm, and the single-pass spraying step to 0.5mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air flow rate is adjusted to 0.02MPa. The droplets are evenly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature is set to 30°C, the solvent is allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 300°C for 15 minutes.

[0057] (4) The acid-catalyzed organosilicon polymer sol prepared in step (1) was diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device. The ultrasonic controller identified and set the parameter signal, set the ultrasonic frequency to 1.0Hz, the liquid feed rate to 0.1ml / min, the nozzle height to 20mm, and the single-pass spraying step to 0.5mm. The sol was dispersed into uniform, tiny droplets by the action of ultrasound and entered the deposition chamber with nitrogen. The gas carrier flow rate was adjusted to 0.02MPa. The droplets were uniformly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature was set to 30°C, the solvent was allowed to evaporate naturally for 1-2 minutes, and the spraying was repeated twice. The solution was then treated at 300°C for 15 minutes.

[0058] (5) The prepared composite membrane was applied to 100 ppm methyl red / NN-dimethylformamide solution for separation.

[0059] Comparative Example 1

[0060] The specific operations of steps (1) and (2) are the same as those in Example 1;

[0061] (3) The acid-base swing organosilicon sol prepared in step (2) was diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device, and the ultrasonic controller identified the set parameter signal, set the ultrasonic frequency to 1.0 Hz, the liquid feed rate to 0.1 ml / min, the nozzle height to 20 mm, and the single-pass spraying step to 0.5 mm. The sol was dispersed into uniform, tiny droplets by the action of ultrasound and entered the deposition chamber with the nitrogen surrounding airflow. The air-carrying flow rate was adjusted to 0.02 MPa, and the droplets were uniformly deposited on the α-Al2O3 support (thickness 5 mm, pore size 200 nm) from the ultrasonic nozzle. The substrate temperature was set to 30°C, the solvent was allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 120°C for 15 minutes.

[0062] (4) The acid-catalyzed organosilicon polymer sol prepared in step (1) is diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device, and the ultrasonic controller recognizes and sets the parameter signal, sets the ultrasonic frequency to 1.0 Hz, the liquid feed rate to 0.1 ml / min, the nozzle height to 20 mm, and the single-pass spraying step to 0.5 mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air-carrying flow rate is adjusted to 0.02 MPa, and the droplets are uniformly deposited on the α-Al2O3 support from the ultrasonic nozzle. The substrate temperature is set to 30°C, the solvent is allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 120°C for 15 minutes.

[0063] (5) The prepared composite membrane was applied to 100 ppm methyl orange / water solution for separation.

[0064] Comparative Example 2

[0065] The specific operations of steps (1) and (2) are the same as those in Example 1;

[0066] (3) The acid-base swing organosilicon sol prepared in step (2) was diluted to 2ωt%, and coated on the anodized aluminum support by wiping (dipping the diluted sol with absorbent cotton and wiping it on the anodized aluminum support, a common conventional method), the coating times were 2 times, and after the wiping was completed, the solution was treated at 300°C for 15 minutes.

[0067] (4) The acid-catalyzed organosilicon polymer sol prepared in step (1) was diluted to 2ωt%, and coated on the anodized aluminum support by wiping method, the coating times were 2 times, and the wiping was completed and the sol was treated at 300°C for 15 minutes.

[0068] (5) The prepared composite membrane was applied to 100 ppm methyl red / NN-dimethylformamide solution for separation.

[0069] Comparative Example 3

[0070] The specific operations of steps (1) and (2) are the same as those in Example 1;

[0071] (3) The acid-base swing organic silicon sol prepared in step (2) is diluted to 4ωt%, drawn into a syringe and connected to an ultrasonic atomization device. The ultrasonic controller identifies and sets the parameter signal, sets the ultrasonic frequency to 1.0Hz, the liquid feed rate to 0.4ml / min, the nozzle height to 20mm, and the single-pass spraying step to 0.5mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air flow rate is adjusted to 0.02MPa. The droplets are evenly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature is set to 30°C, the solvent is allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 120°C for 15 minutes.

[0072] (4) The acid-catalyzed organosilicon polymer sol prepared in step (1) is diluted to 4ωt%, drawn into a syringe and connected to an ultrasonic atomization device. The ultrasonic controller identifies and sets the parameter signal, sets the ultrasonic frequency to 1.0Hz, the liquid feed rate to 0.4ml / min, the nozzle height to 20mm, and the single-pass spraying step to 0.5mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air flow rate is adjusted to 0.02MPa. The droplets are uniformly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature is set to 30°C. The deposition is completed once in 2 minutes. The solvent is allowed to evaporate naturally for 1 to 2 minutes. The spray is applied twice and treated at 120°C for 15 minutes. The surface of the solvent-resistant ultra-thin organosilicon / ceramic composite film is shown in SEM images. Figure 3 .

[0073] (5) The prepared composite membrane was applied to 100 ppm methyl red / NN-dimethylformamide solution for separation.

[0074] Comparative Example 4

[0075] (1) Add 1 g of 1,2-bis(triethoxysilyl)ethane to 15.94 g of n-propanol, stir for 1 to 2 minutes, then dropwise add 2.78 g of deionized water, continue stirring for 1 to 2 minutes, then dropwise add 0.278 g of 3.7% hydrochloric acid, the molar ratio of silicon source precursor, water, and hydrochloric acid is 1:60:0.1, immediately transfer the beaker to a constant temperature water bath at 40°C and continue stirring for 1 hour, then dropwise add ammonia water, the molar ratio of ammonia water to hydrochloric acid is 2:1, continue stirring in a constant temperature water bath at 40°C for 1 hour, finally dropwise add dilute hydrochloric acid, the molar ratio of hydrochloric acid to ammonia water is 2:1, continue stirring in a constant temperature water bath at 40°C for 30 minutes, and obtain a 5 wt% acid-base swing organic silica sol;

[0076] (2) The acid-base swing organic silicon sol prepared in step (1) is diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device, and the ultrasonic controller recognizes and sets the parameter signal, sets the ultrasonic frequency to 1.0 Hz, the liquid inlet speed to 0.1 ml / min, the nozzle height to 20 mm, and the single-pass spraying step to 0.5 mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air-carrying flow rate is adjusted to 0.02 MPa, and the droplets are uniformly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature is set to 30°C, the solvent is allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 120°C for 15 minutes.

[0077] (5) The prepared composite membrane was applied to 100 ppm methyl orange / water solution for separation.

[0078] Comparative Example 5

[0079] (1) Add 1 g of 1,2-bis(triethoxysilyl)ethane to 15.94 g of n-propanol and stir for 1 to 2 minutes. Then, dropwise add 2.78 g of deionized water. Continue stirring for 1 to 2 minutes, then dropwise add 0.278 g of 3.7% hydrochloric acid. The molar ratio of silicon source precursor, water, and hydrochloric acid is 1:60:0.1. Immediately transfer the beaker to a constant temperature water bath at 40°C and continue stirring for 2 hours to obtain a 5 wt% acid-catalyzed organosilicon polymer sol.

[0080] (2) The acid-catalyzed organosilicon polymer sol prepared in step (1) is diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device, and the ultrasonic controller recognizes and sets the parameter signal, sets the ultrasonic frequency to 1.0 Hz, the liquid feed rate to 0.1 ml / min, the nozzle height to 20 mm, and the single-pass spraying step to 0.5 mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air-carrying flow rate is adjusted to 0.02 MPa, and the droplets are uniformly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature is set to 30°C, the solvent is allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 120°C for 15 minutes.

[0081] (3) The prepared composite membrane was applied to 100 ppm methyl orange / water solution for separation.

[0082] Comparative Example 6

[0083] (1) Add 1 g of 1,2-bis(triethoxysilyl)ethane to 15.94 g of n-propanol and stir for 1 to 2 minutes. Then, dropwise add 2.78 g of deionized water. Continue stirring for 1 to 2 minutes, then dropwise add 0.139 g of 3.7% hydrochloric acid. The molar ratio of silicon source precursor, water, and hydrochloric acid is 1:60:0.05. Immediately transfer the beaker to a constant temperature water bath at 40°C and continue stirring for 2 hours to obtain a 5 wt% acid-catalyzed organosilicon polymer sol.

[0084] (2) Add 1 g of 1,2-bis(triethoxysilyl)ethane to 15.94 g of n-propanol and stir for 1 to 2 minutes. Then, add 2.78 g of deionized water dropwise and continue stirring for 1 to 2 minutes. Then, add 0.139 g of 3.7% hydrochloric acid dropwise. The molar ratio of silicon source precursor, water and hydrochloric acid is 1:60:0.05. Immediately transfer the beaker to a constant temperature water bath at 40°C and continue stirring for 1 hour. Then, add ammonia water dropwise. The molar ratio of ammonia water and hydrochloric acid is 2:1. Continue stirring in a constant temperature water bath at 40°C for 1 hour. Finally, add dilute hydrochloric acid dropwise. The molar ratio of hydrochloric acid and ammonia water is 2:1. Continue stirring in a constant temperature water bath at 40°C for 30 minutes to obtain a 5 wt% acid-base swing organic silica sol.

[0085] (3) The acid-base swing organic silicon sol prepared in step (2) is diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device, and the ultrasonic controller recognizes and sets the parameter signal, sets the ultrasonic frequency to 1.0 Hz, the liquid inlet speed to 0.1 ml / min, the nozzle height to 20 mm, and the single-pass spraying step to 0.5 mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air-carrying flow rate is adjusted to 0.02 MPa, and the droplets are uniformly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature is set to 30°C, the solvent is allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 120°C for 15 minutes.

[0086] (4) The acid-catalyzed organosilicon polymer sol prepared in step (1) is diluted to 2ωt%, drawn into a syringe and connected to an ultrasonic atomization device, and the ultrasonic controller recognizes and sets the parameter signal, sets the ultrasonic frequency to 1.0 Hz, the liquid feed rate to 0.1 ml / min, the nozzle height to 20 mm, and the single-pass spraying step to 0.5 mm. The sol is dispersed into uniform, tiny droplets by the action of ultrasound and enters the deposition chamber with the nitrogen surrounding airflow. The air-carrying flow rate is adjusted to 0.02 MPa, and the droplets are uniformly deposited on the anodized aluminum support from the ultrasonic nozzle. The substrate temperature is set to 30°C, the solvent is allowed to evaporate naturally for 1 to 2 minutes, sprayed twice, and treated at 120°C for 15 minutes.

[0087] (5) The prepared composite membrane was applied to 100 ppm methyl orange / water solution for separation.

[0088] The experimental results of the above embodiments and comparative examples are shown in Table 1.

[0089] Table 1

[0090] membrane <![CDATA[Flux L / (m 2 hbar)]]> Dye retention rate (%) Example 1 1.2 98.2 Example 2 0.9 99.4 Comparative Example 1 1.6 20.1 Comparative Example 2 0.2 96.8 Comparative Example 3 0.5 90.4 Comparative Example 4 1.7 72.5 Comparative Example 5 4.3 10.5 Comparative Example 6 1.8 56.6

[0091] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, and all of these should be included in the scope of the present invention.

Claims

1. A method for preparing a solvent-resistant organosilicon / ceramic composite film, characterized in that: include, The organosilicon precursor and inorganic acid are subjected to hydrolysis polymerization reaction with water in an alcohol solvent to prepare an acid-catalyzed organosilicon polymer sol; The organosilicon precursor and inorganic acid are stirred in a constant temperature water bath with water in an alcohol solvent, an alkali catalyst is added and stirred in a constant temperature water bath, and then the inorganic acid is added and stirred in a constant temperature water bath to prepare an acid-base swing organosilicon sol; The diluted acid-base swing organosilicon sol and the diluted acid-catalyzed organosilicon polymer sol are sequentially deposited on a preheated anodic oxide aluminum support, and then post-treated at high temperature to prepare a solvent-resistant organosilicon / ceramic composite membrane.

2. The preparation method according to claim 1, wherein: The method for preparing the acid-catalyzed organosilicon polymer sol comprises: Add the organosilicon precursor to the alcohol solvent and stir for 1-2 minutes; Add deionized water dropwise and continue stirring for 1-2 min; After adding inorganic acid, the mixture was immediately transferred to a constant temperature water bath at 25-60°C and stirred for 2-4 hours to obtain an acid-catalyzed organosilicon polymer sol; wherein, The molar ratio of the organosilicon precursor, deionized water and inorganic acid is 1:30~240:0.1~0.

2.

3. The preparation method according to claim 2, wherein: The organosilicon precursor is a silsesquioxane precursor with a carbon-hydrogen bridge structure, including 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethylene and 1,3-bis(triethoxysilyl)acetylene; the inorganic acid includes HCl; and the alcohol solvent includes n-propanol.

4. The preparation method according to claim 1, wherein: The preparation method of the acid-base swing organosilica sol comprises: Add the organosilicon precursor to the alcohol solvent, stir for 1-2 minutes, then add deionized water dropwise, continue stirring for 1-2 minutes, add the inorganic acid dropwise, and immediately transfer to a constant temperature water bath at 25-60°C and continue stirring for 1-2 hours. The molar ratio of the silicon source precursor, deionized water, and inorganic acid is 1:30-240:0.1-0.

2. Add a base catalyst dropwise, and continue stirring in a constant temperature water bath at 25-60°C for 30-90 minutes. Add an inorganic acid dropwise, and continue stirring in a constant temperature water bath at 25-60°C for 15-120 minutes to obtain an acid-base swing organosilica sol. The molar ratio of the base catalyst to the inorganic acid is 2:1~2.

5. The preparation method according to claim 4, wherein: The base catalyst includes ammonia water, sodium hydroxide and potassium hydroxide, the inorganic acid includes HCl, the alcohol solvent includes n-propanol, and the organosilicon precursor includes 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethylene and 1,3-bis(triethoxysilyl)acetylene.

6. The preparation method according to claim 1, wherein: The diluted acid-base swing organosilicon sol and the diluted acid-catalyzed organosilicon polymer sol are sequentially deposited on the preheated anodized aluminum support, wherein the concentration of the diluted acid-base swing organosilicon sol is 1-5 ωt%, and the concentration of the diluted acid-catalyzed organosilicon polymer sol is 1-5 ωt%.

7. The preparation method according to claim 6, wherein: The pore size of the anodized aluminum support is 10-30 nm and the thickness is 50 μm.

8. The preparation method according to any one of claims 1, 6 or 7, wherein: The deposition method includes deposition through a surrounding airflow-assisted ultrasonic atomization device, wherein the carrier gas assisted by the surrounding airflow includes nitrogen and air, the ultrasonic power is 0.5-3 Hz, the liquid inlet flow rate is 0.1-2 ml / min, the single-pass spraying step is 1-5 mm, the distance between the nozzle and the support is 2-4 cm, the preheating temperature of the anodized aluminum support during deposition is 30-80°C, and the spraying is performed 2-3 times in total.

9. The preparation method according to claim 8, wherein: The high-temperature post-treatment has a treatment temperature of 100-300° C. and a treatment time of 10-30 minutes.

10. The solvent-resistant organosilicon / ceramic composite film prepared by the preparation method according to any one of claims 1 to 9.

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