A liquid-locked double-layer support membrane for gas separation and a preparation method and application thereof

Abstract

The application discloses the field of membrane separation technology, and particularly relates to a liquid-locked double-layer support membrane for gas separation and a preparation method and application thereof. The liquid-locked double-layer support membrane is obtained by preparing a liquid-locked layer membrane with a sandwich structure on a support membrane, is used for separating CO2 in gas, does not cause the problem of ion liquid leakage, improves the stability of the membrane under the premise of obtaining high permeation flux and high selectivity of the gas, overcomes the limitation of the load of the liquid carrier and the type of the liquid carrier, and significantly improves the gas absorption amount.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of membrane separation, and particularly relates to a preparation method of a liquid-locking double-layer supported membrane, and particularly relates to application of the liquid-locking double-layer supported membrane to separation of carbon dioxide in a gas. BACKGROUND

[0002] CO2 emission has caused serious environmental and ecological problems, and carbon capture, utilization and storage technology (CCUS) is an effective way to alleviate CO2 emission. Compared with traditional CO2 capture methods, membrane separation of CO2 has the advantages of small equipment volume, simple operation and low energy consumption, and is considered as the most promising CO2 separation technology, which has attracted high attention in the field of scientific research at home and abroad. Membrane separation of CO2 is divided into gas separation membrane method and membrane desorption method, which usually refers to the separation and purification of CO2 gas under certain conditions by using the pressure difference on both sides of the gas separation membrane as the driving force according to the different permeation rates of each component gas through the gas separation membrane. The form of gas separation membrane is divided into two categories: solid membrane and liquid membrane. Compared with solid separation membrane, liquid membrane has faster mass transfer rate and better selectivity, and has received extensive attention in CO2 separation.

[0003] Supported liquid membrane is a mass transfer membrane composed of liquid membrane phase and support material. The ideal supported liquid membrane should have the excellent transfer characteristics of liquid membrane and the mechanical stability of solid membrane. However, the leakage and volatilization of liquid phase hinder the long-term performance, so it is not suitable for wide application. Gel is a special substance between solid and liquid, and its fiber network structure has good liquid transfer property and solid form stability, so gelation of liquid solution is an effective method to improve the stability of supported liquid membrane.

[0004] Among them, the preparation method of imidazole type ionic liquid gel supported liquid membrane for gas separation in Chinese patent CN103372377A discloses a method for preparing a supported liquid membrane by filling an imidazole type ionic liquid gel into a support material by impregnation or pressurization. In the method, the gel is first prepared by mixing a gel factor and an imidazole type ionic liquid, and then the gel is filled into a porous support material to obtain an ionic liquid gel supported liquid membrane. However, based on the gel state, the fluidity of the fluid is poor, which makes the filling process slow and the filling effect poor. At the same time, the filling process must be combined with pressurization to further reduce the filling efficiency. SUMMARY

[0005] In order to solve the above problems, the application provides a preparation method of a liquid-locking double-layer supported membrane for gas separation, which has good separation effect and good stability. The specific technical scheme is as follows:

[0006] A method for preparing a liquid-locked double-layer supported membrane for gas separation, comprising the following steps:

[0007] 1) Preparation of the liquid-locked layer:

[0008] Mix the gel agent into the sponge layer, so that the gel agent is fully embedded in the pores of the sponge layer;

[0009] Adhere the non-woven fabric to the surface of the sponge layer, to obtain the liquid-locked layer;

[0010] 2) Preparation of the liquid-locked layer membrane:

[0011] Add the liquid-locked layer into the carrier liquid, so that it is fully absorbed by the carrier liquid, and then gel the carrier liquid, to obtain the liquid-locked layer membrane;

[0012] 3) Preparation of the liquid-locked double-layer supported membrane:

[0013] Adhere the porous support membrane to one side of the liquid-locked layer membrane using the adhesive, to obtain the liquid-locked double-layer supported membrane.

[0014] In some preferred embodiments, the liquid-locked double-layer supported membrane is used for separating carbon dioxide CO2 in a gas, wherein the gas comprises carbon dioxide and any one or more of the following: nitrogen, hydrogen, methane, oxygen, VOCs.

[0015] In some preferred embodiments, the amount of the gel agent is 1-10 wt% of the mass of the carrier liquid.

[0016] In some preferred embodiments, the porous support layer is selected from one or more of the following: cellulose acetate CA, polydimethyl sulfoxide PS, polytetrafluoroethylene PTFE, polyvinylidene fluoride PVDF, polyether sulfone PES, polyacrylonitrile PAN, polycellulose, polyethylene terephthalate PET.

[0017] The porous support membrane is subjected to vacuum degassing treatment for 1-2 hours before use.

[0018] In some preferred embodiments, the gel agent is a high-molecular water-absorbing resin SPA, carbon nanotubes, or nanoscale silicon dioxide.

[0019] In some preferred embodiments, the adhesion process uses an adhesive selected from one or more of the following: polyurethane, acrylic acid, phenolic resin.

[0020] The sponge layer is fluff pulp or filter cotton.

[0021] In some preferred embodiments, the pore size of the base membrane is 0.1-0.3 μm.

[0022] In some preferred embodiments, the carrier liquid comprises one or more of the following: an organic amine, a functionalized ionic liquid, an amino acid compound, an aqueous inorganic salt solution;

[0023] wherein,

[0024] The organic amine is selected from one or more of the following: ethanolamine, N-methyldiethanolamine, diethylenetriamine, etc.

[0025] The functionalized ionic liquid is selected from one or more of the following: tetramethylammonium glycine, tetramethylammonium lysine.

[0026] The amino acid compound is selected from one or more of the following: arginine, L-lysine.

[0027] The aqueous inorganic salt solution comprises: a potassium carbonate solution.

[0028] In some preferred embodiments, the morphology of the porous support membrane is selected from one or more of the following: flat plate type, tube type, hollow fiber type.

[0029] The application also provides a liquid-locked double-layer support membrane for gas separation obtained by the preparation method.

[0030] In addition, the application also provides a use of the liquid-locked double-layer support membrane in separating carbon dioxide CO2 from a gas, wherein the gas comprises carbon dioxide and any one or more of the following: nitrogen, hydrogen, methane, oxygen, VOCs; preferably, the gas is carbon dioxide and nitrogen.

[0031] The application has the following beneficial effects:

[0032] 1. The application provides a liquid-locked double-layer support membrane obtained by preparing a liquid-locked layer membrane with a "sandwich" structure on a support membrane, which is used for separating CO2 from a gas and does not have the problem of ionic liquid leakage, and improves the stability of the membrane under the premise of obtaining high permeation flux (the flux can be more than 30 g / (m 2 ·h) and high selectivity.

[0033] 2. The preparation method of the application significantly increases the loadable carrier liquid content in the pore channel of the porous support material by a specific "filling first and gelation later" scheme, and the liquid-locked double-layer support membrane designed in the application can load a significantly increased amount of carrier liquid, so that the mass of the loaded ionic liquid accounts for more than 50% of the total mass of the finished liquid-locked double-layer support membrane, which is 40% higher than the mass of the loaded ionic liquid in the prior art, which accounts for 10% of the total mass of the finished liquid-locked double-layer support membrane, thereby obtaining a higher gas absorption amount.

[0034] 3. The method of the present invention allows for a wider and richer range of carrier liquids to be selected during the preparation process. In addition to various combinations of ionic liquids, there are also amino acid compounds, organic amine solutions, inorganic salt solutions, and combinations of several solutions to meet the requirements of high selectivity and high permeability in the separation process.

[0035] 4. This invention utilizes the volatile properties of ionic liquids to gel them. In addition to common gelling agents such as nano-sized silica and carbon nanotubes, it also uses superabsorbent polymers, which simplifies the gelation process of the carrier liquid. It can gel quickly without stirring, ultrasound, or other methods, thus reducing the cost of large-scale manufacturing. Attached Figure Description

[0036] Figure 1 This is a flowchart of the preparation process of the present invention. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to specific embodiments:

[0038] Example 1

[0039] according to Figure 1 The flowchart shown illustrates the preparation of a liquid-locking bilayer support membrane. The specific steps are as follows:

[0040] 1) Preparation of the liquid-locking layer:

[0041] Sprinkle 10g of superabsorbent polymer (SAP) evenly on the filter cotton and gently rub it to make it better embedded in the cotton pores. Apply polyurethane adhesive to the edges of the two surfaces of the filter cotton and cover it with a non-woven fabric of the same size as the filter cotton. The resulting "sandwich" structure is the liquid-locking layer. Place it in a clean glass petri dish.

[0042] 2) Preparation of the liquid-locking layer film:

[0043] Prepare a 5% tetramethylammonium glycine solution in a sealed glass container and stir it evenly. Pour the solution onto the liquid-locking layer in the glass petri dish of step (1). After the liquid-locking layer has completely absorbed the mixed system and lost its fluidity, slowly wipe away the unabsorbed liquid on the surface of the non-woven fabric with a paper towel to obtain the liquid-locking layer film.

[0044] 3) Preparation of the liquid-locking bilayer support membrane:

[0045] The cellulose acetate membrane (CA) is degassed under vacuum for two hours, and the liquid-locking layer membrane is then superimposed on the degassed CA membrane to obtain the liquid-locking double-layer support membrane.

[0046] Membrane performance test: The lock solution double layer supported membrane was placed in a common membrane separation device for separating CO2 from the mixture of CO2 and N2, and the amount of gas absorption was calculated by the state equation of ideal gas PV = nRT. The absorption rate of carbon dioxide was 0.0205 mol / h, the ideal separation factor was 34, desorption was carried out at room temperature, the flux was 11.13 g / (m 2 ·h), the desorption rate was 35%, and the membrane separation performance remained above 98% after repeated use for more than three times.

[0047] Example 2

[0048] According to the flow chart shown in Figure 1 , a lock solution double layer supported membrane was prepared

[0049] 1) Preparation of the lock solution layer:

[0050] 8 g of nano-sized SiO2 was evenly spread on the fluff pulp, and gently rubbed to better embed it in the cotton pores. Acrylic adhesive was applied to the edges of the two surfaces of the fluff pulp, and a non-woven fabric of the same size as the fluff pulp was covered. The prepared "sandwich" structure was the lock solution layer, which was placed in a clean glass culture dish.

[0051] 2) Preparation of the lock solution layer membrane:

[0052] A 5% arginine solution by mass fraction was prepared in a sealed glass container and uniformly stirred, and then poured onto the lock solution layer in the glass culture dish of step (1). After the lock solution layer absorbed completely and the mixed system lost fluidity, the non-woven fabric surface was slowly wiped with a paper towel to remove the unabsorbed liquid, and a lock solution layer membrane was obtained.

[0053] 3) Preparation of the lock solution double layer supported membrane:

[0054] The polyether sulfone membrane (PES) was vacuum degassed for two hours, and the lock solution layer membrane was stacked on the degassed PES membrane to obtain a lock solution double layer supported membrane.

[0055] Membrane performance test: The lock solution double layer supported membrane was placed in a common membrane separation device for separating CO2 from the mixture of CO2 and N2. The absorption rate of carbon dioxide was 0.0199 mol / h, the ideal separation factor was 55, desorption was carried out at room temperature, the flux was 11.625 g / (m 2 ·h), the desorption rate was 58.02%, and the membrane separation performance remained above 98% after repeated use for more than three times.

[0056] Example 3

[0057] According to the flow chart shown in Figure 1 , a lock solution double layer supported membrane was prepared

[0058] 1) Preparation of the lock solution layer:

[0059] Take 5g of nanoscale SiO2 evenly spread on the filter cotton, gently knead it to better embed it in the cotton holes, and cover the edges of the two surfaces of the filter cotton with polyester amino adhesive. Cover the non-woven fabric of the same size as the filter cotton. The "sandwich" structure obtained is the liquid locking layer, which is placed in a clean glass culture dish.

[0060] 2) Preparation of liquid locking layer membrane:

[0061] Prepare a lysine solution with a mass fraction of 5% in a sealed glass container and stir evenly. Pour it onto the liquid locking layer in the glass culture dish of step (1). After the liquid locking layer absorbs completely and the mixed system loses fluidity, slowly wipe off the unabsorbed liquid on the surface of the non-woven fabric with a paper towel. The liquid locking layer membrane is obtained.

[0062] 3) Preparation of liquid locking double-layer support membrane:

[0063] Vacuum degassing of cellulose acetate membrane (CA) for two hours, and then stack the liquid locking layer membrane on the degassed CA membrane to obtain the liquid locking double-layer support membrane.

[0064] Membrane performance test: Place the liquid locking double-layer support membrane in a commonly used membrane separation device to separate CO2 from the CO2 and N2 mixed gas. The absorption rate of carbon dioxide is 0.0223 mol / h, the ideal separation factor is 37, the desorption is carried out at room temperature, the flux is 28.233 g / (m 2 ·h), the desorption rate is 56.36%, and the membrane separation performance remains above 98% after repeated use for more than three times.

[0065] Example 4

[0066] According to the flow chart shown in Figure 1 to prepare the liquid locking double-layer support membrane

[0067] 1) Preparation of liquid locking layer:

[0068] Take 10g of SAP evenly spread on the filter cotton, gently knead it to better embed it in the cotton holes, and cover the edges of the two surfaces of the filter cotton with phenolic resin adhesive. Cover the non-woven fabric of the same size as the filter cotton. The "sandwich" structure obtained is the liquid locking layer, which is placed in a clean glass culture dish.

[0069] 2) Preparation of liquid locking layer membrane:

[0070] A 5% tetramethylammonium glycine solution was prepared in a closed glass container, mixed with a 25% potassium carbonate solution, and stirred evenly. The mixture was poured onto the lock solution layer in the glass culture dish of step (1), and after the lock solution layer absorbed completely and the mixed system lost fluidity, the unabsorbed liquid on the surface of the non-woven fabric was slowly wiped off with a paper towel, and a lock solution layer membrane was obtained.

[0071] 3) Preparation of lock solution double-layer support membrane:

[0072] The polyvinylidene fluoride (PVDF) was vacuum degassed for two hours, and the lock solution layer membrane was stacked on the degassed PVDF membrane to obtain the lock solution double-layer support membrane.

[0073] Membrane performance test: The lock solution double-layer support membrane was placed in a commonly used membrane separation device for separating CO2 from a CO2 and N2 mixed gas. The absorption rate of carbon dioxide was 0.0193 mol / h, the ideal separation factor was 32, desorption was carried out at room temperature, the flux was 7.473 g / (m 2 ·h), the desorption rate was 16.92%, and the membrane separation performance remained above 98% after repeated use for more than three times.

[0074] Example 5

[0075] According to the flowchart shown in Figure 1 , a lock solution double-layer support membrane was prepared

[0076] 1) Preparation of lock solution layer:

[0077] 10 g of SAP was evenly spread on the fluff pulp, and gently kneaded to better embed it in the cotton pores. Acrylic adhesive was applied to the edges of the two surfaces of the fluff pulp, and a non-woven fabric of the same size as the fluff pulp was covered. The "sandwich" structure obtained was the lock solution layer, which was placed in a clean glass culture dish.

[0078] 2) Preparation of lock solution layer membrane:

[0079] A 5% arginine solution was prepared in a closed glass container, mixed with a 25% potassium carbonate solution, and stirred evenly. The mixture was poured onto the lock solution layer in the glass culture dish of step (1), and after the lock solution layer absorbed completely and the mixed system lost fluidity, the unabsorbed liquid on the surface of the non-woven fabric was slowly wiped off with a paper towel, and a lock solution layer membrane was obtained.

[0080] 3) Preparation of lock solution double-layer support membrane:

[0081] The cellulose acetate membrane (CA) was vacuum degassed for two hours, and the lock solution layer membrane was stacked on the degassed CA membrane to obtain the lock solution double-layer support membrane.

[0082] Membrane performance test: The liquid-locked double-layer supported membrane was placed in a commonly used membrane separation device for separating CO2 from a CO2 and N2 mixed gas, the absorption rate of carbon dioxide was 0.0386 mol / h, the ideal separation factor was 64, desorption was carried out at room temperature, the flux was 9.965 g / (m 2 ·h), the desorption rate was 13.96%, and the membrane separation performance remained above 98% after being reused more than three times.

[0083] Comparative example

[0084]

[0085]

Claims

1. A method for preparing a liquid-locking bilayer supported membrane for gas separation, characterized in that, Includes the following steps: 1) Preparation of the liquid-locking layer: The gel is mixed into the sponge layer so that the gel is fully embedded in the pores of the sponge layer; By adhering nonwoven fabric to the surface of the sponge layer, a liquid-locking layer is obtained. 2) Preparation of the liquid-locking layer film: Add the liquid-locking layer to the carrier liquid, allow it to fully absorb the carrier liquid, and wait for the carrier liquid to gel to obtain the liquid-locking layer film; 3) Preparation of the liquid-locking bilayer support membrane: A porous support membrane is adhered to one side of the liquid-locking layer membrane using an adhesive to obtain a liquid-locking double-layer support membrane.

2. The preparation method according to claim 1, characterized in that, The liquid-locking double-layer support membrane is used to separate carbon dioxide (CO2) from a gas, wherein the gas includes carbon dioxide and any one or more of the following: nitrogen, hydrogen, methane, oxygen, and VOCs.

3. The preparation method according to claim 1, characterized in that, The amount of gelling agent used is 1 to 10 wt% of the carrier liquid mass.

4. The preparation method according to claim 1, characterized in that, The porous support membrane is selected from one or more of the following: polyacetal cellulose (CA), polystyrene (PS), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethersulfone (PES), polyacrylonitrile (PAN), polycellulose, and polyethylene terephthalate (PET). The porous support membrane undergoes vacuum degassing treatment for 1-2 hours before use.

5. The preparation method according to claim 1, characterized in that, The gelling agent is superabsorbent polymer (SAP), carbon nanotubes, or nanoscale silica.

6. The preparation method according to claim 1, characterized in that, The adhesion process uses an adhesive selected from one or more of the following: polyurethane, acrylic, and phenolic resin.

7. The preparation method according to claim 1, characterized in that, The porous support membrane has a pore size of 0.1 μm to 0.3 μm.

8. The preparation method according to claim 1, characterized in that, The carrier liquid includes one or more of the following: organic amines, functionalized ionic liquids, amino acid compounds, and aqueous solutions of inorganic salts; in, The organic amine is selected from one or more of the following substances: ethanolamine, N-methyldiethanolamine, diethylenetriamine, etc.; Functionalized ionic liquids are selected from one or more of the following substances: tetramethylammonium glycine, tetramethylammonium lysine; The amino acid compounds are selected from one or more of the following substances: arginine, L-lysine; Inorganic salt aqueous solutions include: potassium carbonate solution.

9. A liquid-locking bilayer support membrane for gas separation obtained by the preparation method according to any one of claims 1 to 8.

10. The application of the liquid-locking double-layer support membrane of claim 9 in the process of separating carbon dioxide (CO2) from a gas, wherein the gas comprises carbon dioxide and any one or more of the following: nitrogen, hydrogen, methane, oxygen, and VOCs.

11. The application of the liquid-locking double-layer support membrane according to claim 10 in the process of separating carbon dioxide (CO2) from gases, characterized in that, The gas is carbon dioxide and nitrogen.

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