Preparation method of GO / Al2O3 composite ceramic ultrafiltration membrane

Abstract

The application discloses a preparation method of GO / Al2O3 composite ceramic ultrafiltration membrane, and comprises the following steps: step one, weighing graphene oxide into a container, adding distilled water, stirring and dispersing on a constant-temperature water bath magnetic stirrer, and then using an ultrasonic dispersing instrument for ultrasonic dispersion to obtain a graphene oxide dispersion liquid; step two, weighing pseudoboehmite, dissolving the pseudoboehmite in the graphene oxide dispersion liquid, stirring and dispersing on the constant-temperature water bath magnetic stirrer, then using a constant-pressure dropping funnel to drop a calculated amount of nitric acid, continuing to stir and gelatinize, and obtaining a GO / AlOOH mixed sol; step three, weighing a PVA solution and the GO / AlOOH mixed sol with a mass ratio of 1:1, stirring, and obtaining a coating solution; and step four, using an immersion method to coat the coating solution on the surface of a substrate. The preparation method of the GO / Al2O3 composite ceramic ultrafiltration membrane is simple in technological process, friendly to the environment, smaller in ceramic membrane pore size, and stronger in permeability.

Description

Technical Field

[0001] This invention relates to the field of composite ceramic ultrafiltration membrane preparation technology, specifically a method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane. Background Technology

[0002] In recent years, graphene oxide membranes (GOMs) have become a research hotspot in the field of membrane materials due to their advantages such as ultrathin thickness, excellent molecular sieving ability, high chemical stability, and high mechanical strength. The interlayer spacing of graphene oxide (GO) itself is about 0.35-0.45 nm, while the interlayer spacing of GOMs formed by stacking GO sheets is between 0.78-0.80 nm. This spacing allows water molecules to pass freely while repelling most molecules and ions, showing broad application prospects in nanofiltration and reverse osmosis. The basal surface or edge of graphene oxide (GO) contains a large number of hydrophilic oxygen-containing functional groups (carboxyl, hydroxyl, epoxy, carbonyl, etc.). These groups endow GO with excellent dispersibility, hydrophilicity, and compatibility with substrates, and also provide reaction sites for the functional modification of GO. Therefore, GOMs formed by stacking a large number of sheet-like GOs have excellent separation performance. However, the spatial constraints of GOM nanoscale structures limit the transport of water molecules within the membrane, restricting water flux while maintaining retention performance. Reduced water flux leads to inefficiency and high consumption. Existing methods for controlling the internal structure of GOM mainly focus on regulating the pore structure between GOM nanosheets, interlayer spacing, and the degree of order in the layered structure. Current methods for preparing GOM / Al2O3 composite ceramic ultrafiltration membranes involve directly depositing graphene oxide onto an alumina ultrafiltration membrane using vacuum filtration. This method cannot effectively embed or embed GOM, nor can it control the degree of order in the GOM membrane structure. Furthermore, membrane delamination or interlayer expansion is highly likely to occur, significantly reducing the membrane's separation performance. Therefore, we propose a method for preparing GOM / Al2O3 composite ceramic ultrafiltration membranes. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a method for preparing GO / Al2O3 composite ceramic ultrafiltration membrane. The process is simple, environmentally friendly, and the ceramic membrane has smaller pore size and stronger permeability, which can effectively solve the problems in the background technology.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane, the method comprising the following steps:

[0005] Step 1: Weigh out graphene oxide and pour it into a container, add distilled water, stir and disperse it on a constant temperature water bath magnetic stirrer, and then use an ultrasonic disperser to disperse it ultrasonically to obtain a graphene oxide dispersion.

[0006] Step 2: Weigh out the pseudoboehmite, dissolve it in the graphene oxide dispersion, and place it on a constant temperature water bath magnetic stirrer to stir and disperse. Then, use a constant pressure dropping funnel to add the calculated amount of nitric acid dropwise, and continue stirring to dissolve the gel, to obtain a GO / AlOOH mixed sol.

[0007] Step 3: Weigh out a 1:1 PVA solution and a GO / AlOOH mixed sol, and stir them to obtain the coating solution;

[0008] Step 4: Apply the coating to the substrate surface using the impregnation method, and then dry and calcine at high temperature to obtain the GO / Al2O3 composite ceramic ultrafiltration membrane.

[0009] Preferably, in step one, the mass ratio of graphene oxide to boehmite is 1:50 to 1:200, and the ultrasonic time is 0.5 to 2 hours.

[0010] Preferably, in step two, the mass ratio of boehmite to water is 1:10 to 1:20, and the molar ratio of nitric acid to boehmite is 1:5.

[0011] Preferably, the heating and stirring temperature in step two is 25°C, and the gelation time is 5–40 min.

[0012] Preferably, the PVA solution added to the coating solution in step three is a film-forming agent, and the PVA concentration is 2% to 4%.

[0013] Preferably, the substrate material used for coating in step four is alumina, zirconium oxide, or silicon carbide porous ceramic or porous ceramic microfiltration membrane.

[0014] Preferably, the drying process for the composite ceramic ultrafiltration membrane in step four is as follows: drying temperature in a forced-air drying oven is 60-80℃, and drying time is 1-3 hours.

[0015] Preferably, in step four, the composite ceramic ultrafiltration membrane is calcined in a muffle furnace with the following conditions: calcination temperature of 400–600°C, heating rate of 0.5–2°C / min, and holding time of 0.5–2h.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The preparation method of the GO / Al2O3 composite ceramic ultrafiltration membrane has the following advantages:

[0017] 1. When preparing aluminum sol, graphene oxide is directly added to the aluminum sol, so that the sheet-like graphene oxide is uniformly dispersed in the aluminum oxide separation membrane layer. GO is completely embedded or embedded, which better controls the internal pores of the GO membrane and increases the separation performance of the GO / Al2O3 composite ceramic ultrafiltration membrane.

[0018] 2. The process is simpler and more environmentally friendly. The ceramic membrane prepared has smaller pore size and stronger permeability, which is expected to enable the GO / Al2O3 composite ceramic ultrafiltration membrane to develop towards the direction of reverse osmosis membrane. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the pure graphene oxide structure of the present invention;

[0020] Figure 2 This is a schematic diagram of the planar morphology of the Al2O3 ceramic film of the present invention;

[0021] Figure 3 This is a schematic diagram of the planar morphology of the GO / Al2O3 composite ceramic ultrafiltration membrane of the present invention;

[0022] Figure 4 This is a schematic diagram of the graphene oxide intercalation structure of the GO / Al2O3 composite ceramic ultrafiltration membrane of the present invention. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1-4 This embodiment provides a technical solution: a method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane;

[0025] Example 1:

[0026] A method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane, comprising the following steps:

[0027] Step 1: Weigh out graphene oxide and pour it into a container, and add distilled water. The mass ratio of graphene oxide to boehmite is 1:50. Stir and disperse the graphene oxide on a constant temperature water bath magnetic stirrer, and then use an ultrasonic disperser to ultrasonically disperse the graphene oxide for 0.5 hours to obtain a graphene oxide dispersion.

[0028] Step 2: Weigh out boehmite and dissolve it in graphene oxide dispersion. The mass ratio of boehmite to water is 1:10. Place the solution on a constant temperature water bath magnetic stirrer and stir to disperse. Then, use a constant pressure dropping funnel to add the calculated amount of nitric acid. The molar ratio of nitric acid to boehmite is 1:5. Continue stirring and gelation at 25°C for 5 minutes to obtain GO / AlOOH mixed sol.

[0029] Step 3: Weigh out a 1:1 PVA solution and a GO / AlOOH mixed sol, and stir them to obtain a coating solution. The PVA solution added to the coating solution is a film-forming agent with a PVA concentration of 2%.

[0030] Step 4: Apply a coating to the substrate surface using an impregnation method. The substrate material used for coating is porous ceramic or porous ceramic microfiltration membrane made of alumina, zirconium oxide, or silicon carbide. The coating is then dried and calcined at high temperature. The drying process is as follows: drying in a forced-air drying oven at 60°C for 1 hour. The high-temperature calcination is carried out using a muffle furnace calcination mechanism: calcination temperature at 400°C, heating rate at 0.5°C / min, and holding time at 0.5 hours to obtain the GO / Al2O3 composite ceramic ultrafiltration membrane.

[0031] Example 2:

[0032] A method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane, comprising the following steps:

[0033] Step 1: Weigh out graphene oxide and pour it into a container, and add distilled water. The mass ratio of graphene oxide to boehmite is 1:100. Stir and disperse the graphene oxide on a constant temperature water bath magnetic stirrer, and then use an ultrasonic disperser to disperse it for 1 hour to obtain a graphene oxide dispersion.

[0034] Step 2: Weigh out boehmite and dissolve it in graphene oxide dispersion. The mass ratio of boehmite to water is 1:15. Place the solution on a constant temperature water bath magnetic stirrer and stir to disperse. Then, use a constant pressure dropping funnel to add the calculated amount of nitric acid. The molar ratio of nitric acid to boehmite is 1:5. Continue stirring and gelation at 25°C for 20 minutes to obtain GO / AlOOH mixed sol.

[0035] Step 3: Weigh out a 1:1 PVA solution and a GO / AlOOH mixed sol, and stir them to obtain a coating solution. The PVA solution added to the coating solution is a film-forming agent with a PVA concentration of 3%.

[0036] Step 4: Apply a coating to the substrate surface using an impregnation method. The substrate material used for coating is porous ceramic or porous ceramic microfiltration membrane made of alumina, zirconium oxide, or silicon carbide. The coating is then dried and calcined at high temperature. The drying process is as follows: drying temperature in a forced-air drying oven is 70℃, and the drying time is 2 hours. The high-temperature calcination is carried out using a muffle furnace calcination mechanism: calcination temperature is 500℃, heating rate is 1℃ / min, and holding time is 1 hour to obtain the GO / Al2O3 composite ceramic ultrafiltration membrane.

[0037] Example 3:

[0038] A method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane, comprising the following steps:

[0039] Step 1: Weigh out graphene oxide and pour it into a container, and add distilled water. The mass ratio of graphene oxide to boehmite is 1:200. Stir and disperse the graphene oxide on a constant temperature water bath magnetic stirrer, and then use an ultrasonic disperser to disperse it for 2 hours to obtain a graphene oxide dispersion.

[0040] Step 2: Weigh out boehmite and dissolve it in graphene oxide dispersion. The mass ratio of boehmite to water is 1:20. Place the solution on a constant temperature water bath magnetic stirrer and stir to disperse. Then, use a constant pressure dropping funnel to add the calculated amount of nitric acid. The molar ratio of nitric acid to boehmite is 1:5. Continue stirring and gelation at 25°C for 40 minutes to obtain GO / AlOOH mixed sol.

[0041] Step 3: Weigh out a 1:1 PVA solution and a GO / AlOOH mixed sol, and stir them to obtain a coating solution. The PVA solution added to the coating solution is a film-forming agent with a PVA concentration of 4%.

[0042] Step 4: Apply a coating to the substrate surface using an impregnation method. The substrate material used for coating is porous ceramic or porous ceramic microfiltration membrane made of alumina, zirconium oxide, or silicon carbide. The coating is then dried and calcined at high temperature. The drying process is as follows: drying temperature in a forced-air drying oven is 80℃, and the drying time is 3 hours. The high-temperature calcination is carried out using a muffle furnace calcination mechanism: calcination temperature is 600℃, heating rate is 2℃ / min, and holding time is 2 hours to obtain the GO / Al2O3 composite ceramic ultrafiltration membrane.

[0043] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane, characterized in that: The preparation method of the GO / Al2O3 composite ceramic ultrafiltration membrane includes the following steps: Step 1: Weigh out graphene oxide and pour it into a container, add distilled water, stir and disperse it on a constant temperature water bath magnetic stirrer, and then use an ultrasonic disperser to disperse it ultrasonically to obtain a graphene oxide dispersion. Step 2: Weigh out the pseudoboehmite, dissolve it in the graphene oxide dispersion, and place it on a constant temperature water bath magnetic stirrer to stir and disperse. Then, use a constant pressure dropping funnel to add the calculated amount of nitric acid dropwise, and continue stirring to dissolve the gel, to obtain a GO / AlOOH mixed sol. Step 3: Weigh out a 1:1 PVA solution and a GO / AlOOH mixed sol, and stir them to obtain the coating solution; Step 4: Apply the coating to the substrate surface using the impregnation method, and then dry and calcine at high temperature to obtain the GO / Al2O3 composite ceramic ultrafiltration membrane.

2. The method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane according to claim 1, characterized in that: In step two, the mass ratio of boehmite to water is 1:10 to 1:20, and the molar ratio of nitric acid to boehmite is 1:

5.

3. The method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane according to claim 1, characterized in that: In step two, the heating and stirring temperature is 25°C, and the gelation time is 5–40 min.

4. The method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane according to claim 1, characterized in that: The PVA solution added to the coating solution in step three is a film-forming agent, and the PVA concentration is 2% to 4%.

5. The method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane according to claim 1, characterized in that: The substrate material used for coating in step four is alumina, zirconium oxide, or silicon carbide porous ceramic or porous ceramic microfiltration membrane.

6. The method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane according to claim 1, characterized in that: The drying process for the composite ceramic ultrafiltration membrane in step four is as follows: drying temperature in a forced-air drying oven is 60-80℃, and drying time is 1-3 hours.

7. The method for preparing a GO / Al2O3 composite ceramic ultrafiltration membrane according to claim 1, characterized in that: In step four, the composite ceramic ultrafiltration membrane is calcined in a muffle furnace at the following conditions: calcination temperature of 400–600℃, heating rate of 0.5–2℃ / min, and holding time of 0.5–2h.

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