Microalgae direct air carbon capture air inlet device for adhering carbonic anhydrase based on layer deposition method

Abstract

The invention discloses a layer deposition method-based carbonic anhydrase attached microalgae direct air carbon capture air inlet device, which comprises a photobioreactor, an air pump air inlet pipe and an air inlet membrane assembly, a microalgae solution is contained in the photobioreactor, and the air inlet membrane assembly is installed at the outlet end of the air pump air inlet pipe and is immersed in the microalgae solution. The air inlet membrane component consists of a mounting component and a porous fiber membrane attached with carbonic anhydrase; the porous fiber membrane attached with carbonic anhydrase is mounted at the outlet end of the air inlet pipe of the air pump through the mounting assembly, so that inlet air enters the microalgae solution after passing through the porous fiber membrane attached with carbonic anhydrase. By optimizing the gas inlet membrane assembly, the problems of slow carbon dioxide transmission, low carbon dioxide solubility and the like in the original reactor are solved, and meanwhile, by combining the membrane material and attached carbonic anhydrase with the gas inlet assembly, the contact area of carbon dioxide gas and the membrane material is further increased, and the mass transfer coefficient of CO2 is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of microalgae carbon fixation, relates to a direct air carbon capture photobioreactor, and particularly relates to a microalgae direct air carbon capture air intake device based on a layer stacking method to attach carbonic anhydrase. Background Art

[0002] Among the numerous direct air carbon capture technologies, microalgae, as one of the microorganisms with a higher photosynthesis rate, has the advantages of fast carbon fixation rate, small footprint, clean and pollution-free. In recent years, it has been considered as one of the efficient carbon fixation pathways with development prospects. Since the CO2 concentration in direct air carbon capture is low (about 0.04%), and the CO2 concentration suitable for the growth of most microalgae species is above 3%, under traditional methods, the photosynthesis rate of microalgae is slow, and the efficiency of CO2 dissolution and conversion into bicarbonate in water is not enough to meet the requirements of high-speed carbon fixation. Therefore, to improve the efficiency of microalgae in capturing CO2 directly from the air, the key point of research is to improve the enrichment and transmission efficiency of CO2.

[0003] In the existing technologies, researchers have made a lot of optimizations and innovative designs on the structure, configuration, and air intake components of photobioreactors. For example, membrane photobioreactors are used to optimize the mass transfer efficiency of CO2 and microalgae, and devices such as air stones and bubbling towers are used to optimize the bubble size. Due to the low concentration of CO2 in the air, it is difficult to meet the carbon fixation rate requirements using traditional photobioreactors. Some researchers have also proposed using catalysts such as carbonic anhydrase to assist carbon fixation. Carbonic anhydrase has obvious advantages in promoting the dissolution and absorption of CO2 and improving the aggregation characteristics of CO2 in the air, but the way carbonic anhydrase is combined with the reactor and how to effectively avoid failure during long-term use are still difficult points in technical research. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a microalgae direct air carbon capture intake device based on the layer stacking method to attach carbonic anhydrase, so as to further improve the efficiency of air CO2 capture.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A microalgae direct air carbon capture intake device with carbonic anhydrase attached based on a layer stacking method comprises a photobioreactor, an air pump intake pipe and an intake membrane assembly, wherein a microalgae solution is contained in the photobioreactor, and the intake membrane assembly is installed at the outlet end of the air pump intake pipe and immersed in the microalgae solution. The invention is characterized in that the intake membrane assembly consists of a mounting assembly and a porous fiber membrane with carbonic anhydrase attached; the porous fiber membrane with carbonic anhydrase attached is installed at the outlet end of the air pump intake pipe through the mounting assembly, so that the intake air enters the microalgae solution after passing through the porous fiber membrane with carbonic anhydrase attached.

[0007] In one embodiment, the installation assembly includes: a hollow fixing nut, a first metal breathable fixing structure, a second metal breathable fixing structure and a hollow fixing nut; the porous fiber membrane attached with carbonic anhydrase is clamped between the first metal breathable fixing structure and the second metal breathable fixing structure, and installed at the end of the hollow fixing nut, and the hollow fixing nut is assembled into one body with the hollow fixing nut and installed at the outlet end of the air pump intake pipe.

[0008] In one embodiment, the first metal air-permeable fixing structure and the second metal air-permeable fixing structure are composed of a porous metal plate, the pore size of the porous metal plate is larger than the pore size of the porous fiber membrane, the first metal air-permeable fixing structure, the second metal air-permeable fixing structure and the porous fiber membrane are clamped by the stress between the hollow fixing nut and the groove on the hollow fixing nut, and the hollow fixing nut and the hollow fixing nut are connected by a threaded structure, and the air intake pipe is inflated in the hollow structure.

[0009] In one embodiment, the porous fiber membrane with attached carbonic anhydrase has a nylon support material as a substrate, and uses an electrospinning method to deposit polymer fiber filaments on the substrate, prepare a polysulfone solution, perform electrospinning, and attach carbonic anhydrase and polyelectrolyte to both sides of the substrate on which the polymer fiber filaments are deposited by a layer stacking method.

[0010] In one embodiment, carbonic anhydrase is attached to the porous fiber membrane by a layer stacking method, specifically: based on the electrostatic adsorption characteristics of polyelectrolyte and carbonic anhydrase, polyelectrolyte solution and carbonic anhydrase solution with equal concentrations are respectively prepared, and the porous fiber membrane is placed in the solutions in sequence for attachment.

[0011] In one embodiment, the polyelectrolyte solution is composed of polyethyleneimine (PEI), sodium polystyrene sulfonate (PSS) and polyallylamine hydrochloride (PAH), and the order of stacking attachment is PEI / PSS / PAH / [PSS / PAH / CA]3, wherein CA represents carbonic anhydrase, and the subscript 3 represents the number of layers of attached carbonic anhydrase.

[0012] The present invention also provides a method for preparing the microalgae direct air carbon capture intake device based on the layer stacking method with attached carbonic anhydrase, characterized in that it comprises:

[0013] Cultivating a microalgae solution and placing it in a photobioreactor;

[0014] preparing a porous fiber membrane attached with carbonic anhydrase;

[0015] The porous fiber membrane with carbonic anhydrase attached is installed at the outlet end of the air intake pipe of the air pump by means of an installation component;

[0016] The air pump inlet pipe is connected to the photobioreactor, and the outlet end thereof is immersed in the microalgae solution.

[0017] In one embodiment, the preparation method of the porous fiber membrane with attached carbonic anhydrase is as follows:

[0018] Step 1, preparing electrospinning film-making solution;

[0019] Step 2, performing electrospinning on the surface of the nylon fiber membrane;

[0020] Step 3: attach carbonic anhydrase and polyelectrolyte by layer stacking method.

[0021] In one embodiment, the preparation process of the electrospinning film-forming solution is as follows:

[0022] Add polysulfone PSU particles at a solid mass fraction of 12-18wt.% to N,N-dimethylacetamide to prepare a membrane-making solution, stir thoroughly until dissolved evenly, and let stand overnight for degassing treatment after stirring.

[0023] In one embodiment, the layer stacking method attaches carbonic anhydrase and polyelectrolyte as follows:

[0024] The electrospun membrane was peeled off from the support and three polyelectrolyte solutions of polyethyleneimine (PEI), sodium polystyrene sulfonate (PSS) and polyallylamine hydrochloride (PAH) were prepared according to the formula of PEI / PSS / PAH / [PSS / PAH / CA] x The layers are stacked in the order of , and carbonic anhydrase (CA) is attached to the prepared electrospinning membrane by utilizing the principle of electrostatic adsorption, where x represents the number of layers of attached CA.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The carbon fixation rate of direct air capture of CO2 by microalgae has been greatly improved. By optimizing the air inlet membrane component, the problems of slow CO2 transmission and low CO2 solubility in the original reactor have been improved. At the same time, by combining the membrane material and the attached carbonic anhydrase with the air inlet component, the contact area between the CO2 gas and the membrane material has been further increased, greatly reducing the CO2 mass transfer coefficient.

[0027] (2) A breathable metal frame composite structure in the form of a membrane air intake assembly is proposed. The electrospun membrane material attached with carbonic anhydrase in the form of an air intake membrane assembly is fixed by two layers of metal mesh or breathable metal material, and has stronger mechanical strength, which improves the problem of easy damage and poor durability of the polymer fiber membrane.

[0028] (3) The mixed electrospinning composite membrane prepared by the electrospinning method has the characteristics of high air permeability and good hydrophilicity. The method of attaching carbonic anhydrase by the combined layer stacking method effectively increases the carbonic anhydrase loading per unit area. In addition, due to electrostatic adsorption, the attached carbonic anhydrase is not easy to fall off and has better durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the direct air carbon capture intake device system of microalgae with attached carbonic anhydrase in the present invention.

[0030] Figure 2 for Figure 1 A magnified view of area in center.

[0031] Figure 3 It is a cross-sectional schematic diagram of the membrane air intake assembly of the present invention.

[0032] Figure 4 for Figure 3 Magnified view of area B.

[0033] Figure 5 Schematic diagram of the carbonic anhydrase membrane attached based on the layer stacking method prepared in the present invention.

[0034] Figure 6 Schematic diagram of the raceway pool photobioreactor and air intake device used in the embodiment of the present invention.

[0035] Figure 7 The figure is a flow chart of the preparation of the carbonic anhydrase membrane attached based on the layer stacking method in the embodiment of the present invention.

[0036] Figure 8 4 is a comparison chart of carbon fixation rates of different control groups in the examples of the present invention. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below with reference to the accompanying drawings and examples.

[0038] like Figure 1 and Figure 2 As shown, the present invention is a microalgae direct air carbon capture intake device with carbonic anhydrase attached based on the layer stacking method, comprising a photobioreactor 1, an air pump intake pipe 3 and an intake membrane assembly 4, wherein the photobioreactor 1 contains a microalgae solution 2, and the intake membrane assembly 4 is installed at the outlet end of the air pump intake pipe 3 and immersed in the microalgae solution 2, that is, according to this structure, the intake air from the air pump intake pipe 3 needs to pass through the intake membrane assembly 4, and directly enters the microalgae solution 2 in the photobioreactor 1 after passing through.

[0039] In the present invention, the photobioreactor 1 can use any form of photobioreactor configuration. This embodiment uses a raceway pool photobioreactor. However, as an improvement for air intake, the present invention has no requirements for the reactor type. There are no requirements for the algae species and types of microalgae in the microalgae solution 2. The air pump air intake pipe 3 is used to connect the air pump and the air intake membrane assembly 4 to provide sufficient gas aeration in the photobioreactor 1.

[0040] For example, in an embodiment of the present invention, based on the low concentration carbon fixation requirement and the culture conditions at room temperature, Chlorella pyrenoidosa was selected as the algae species, a 0.1 g / L microalgae solution 2 was prepared, and MLA nutrient solution was added, with a specific formula of 49.10 mg·L - 1 MgSO4·7H2O,170.00mg·L -1 NaNO3, 34.80mg·L -1 K2HPO4, 2.40mg·L -1 H3BO3, 16.80mg·L - 1 NaHCO3, 29.40 mg·L -1 CaCl2·2H2O,0.0012mg·L -1 H2SeO3 as well as vitamins and trace elements.

[0041] The air intake membrane assembly 4 is a key component of the present invention, which is composed of a mounting assembly and a porous fiber membrane 7 with carbonic anhydrase attached. The porous fiber membrane 7 with carbonic anhydrase attached is installed at the outlet end of the air pump intake pipe 3 through the mounting assembly. The aforementioned intake air specifically enters the microalgae solution 2 after passing through the porous fiber membrane 7 with carbonic anhydrase attached.

[0042] The present invention requires the intake air to pass through the porous fiber membrane 7 attached with carbonic anhydrase, that is, the air directly enters the photobioreactor through the air pump and the intake membrane assembly 4, wherein low-concentration carbon dioxide can be converted into bicarbonate more quickly with the assistance of carbonic anhydrase, thereby improving the carbon fixation efficiency of microalgae at low concentrations. Therefore, with the help of the above-mentioned characteristics of carbonic anhydrase, the carbonic anhydrase-assisted intake device of the present invention can effectively improve the efficiency and durability of microalgae direct air capture and fixation of air concentration CO2.

[0043] In a further embodiment of the present invention, a specific structure of the mounting assembly is provided, such as Figure 2 As shown, the installation assembly includes: a hollow fixing nut 5, a first metal air-permeable fixing structure 6, a second metal air-permeable fixing structure 8 and a hollow fixing nut 9. The porous fiber membrane 7 attached with carbonic anhydrase is clamped between the first metal air-permeable fixing structure 6 and the second metal air-permeable fixing structure 8, and is installed on the threaded end of the hollow fixing nut 5. The hollow fixing nut 5 and the hollow fixing nut 9 are assembled into one body and installed on the outlet end of the air pump intake pipe 3.

[0044] Furthermore, if Figure 3 and Figure 4 As shown, the first metal breathable fixed structure 6 and the second metal breathable fixed structure 8 in the embodiment of the present invention are both composed of porous metal plates, which can effectively solve the problems of low mechanical strength and easy breakage of the porous fiber membrane. The first metal breathable fixed structure 6 and the second metal breathable fixed structure 8 are consistent in size, which is convenient for processing and assembly. There is no need to make more restrictions on the aperture of the porous metal plate, it only needs to be larger than the aperture of the porous fiber membrane 7, and in order to ensure the air intake effect, it should generally be greater than 50 microns. The first metal breathable fixed structure 6, the second metal breathable fixed structure 8 and the porous fiber membrane 7 can be clamped by the stress between the grooves on the hollow fixing nut 5 and the hollow fixing nut 9, and then the hollow fixing nut 5 and the hollow fixing nut 9 can be connected by a threaded structure, and the air intake pipe is inflated in the hollow structure.

[0045] This embodiment adopts a metal mesh composite structure. The electrospun membrane material attached with carbonic anhydrase in the form of an air-intake membrane assembly is fixed by two layers of metal mesh or breathable metal materials, and has stronger mechanical strength, thereby improving the problem of easy damage and poor durability of the polymer fiber membrane.

[0046] In a further embodiment of the present invention, in order to strengthen the durability and structural strength of carbonic anhydrase, a specific preparation method of a porous fiber membrane 7 with carbonic anhydrase attached is provided, in which a nylon support material (typically a nanofiber membrane such as a nylon fiber membrane) is used as a substrate, and an electrostatic spinning method is used to deposit polymer fiber filaments on a substrate rotating at a high speed, and carbonic anhydrase and polyelectrolyte are attached to both sides of the substrate on which the polymer fiber filaments are deposited by a layer stacking method. For example, in the present embodiment, electrostatic spinning uses a polysulfone (PSU) solution, and the concentration of the polysulfone solution is 12-18wt.%, further selected as 15wt.%, and the parameters of electrostatic spinning are preferably 2mL / h electrostatic spinning 8h.

[0047] This embodiment improves the problems of slow carbon dioxide transmission and low carbon dioxide solubility in the original reactor through the above-mentioned air intake membrane assembly 4. At the same time, by combining the membrane material and the attached carbonic anhydrase with the air intake assembly, the contact area between the carbon dioxide gas and the membrane material is further increased, the mass transfer coefficient of CO2 is greatly reduced, and the carbon fixation rate of microalgae direct air capture of CO2 is greatly increased. In addition, the mixed electrospinning composite membrane prepared by the electrospinning method has the characteristics of high air permeability and good hydrophilicity. The method of attaching carbonic anhydrase by the layer stacking method effectively increases the carbonic anhydrase loading per unit area. Due to electrostatic adsorption, the attached carbonic anhydrase is not easy to fall off and has better durability.

[0048] In this embodiment, the electrospun membrane with carbonic anhydrase attached is fixed between two layers of metal air-permeable structures, and the gas is introduced from a section of the air intake assembly through an air pump. After the gas bubbles are refined by the electrospun membrane and carbonic anhydrase promotes the conversion of carbon dioxide into bicarbonate, the gas is introduced into the photobioreactor 1 to supply the growth of microalgae. The spacing between the porous fiber membrane 7 and the fixed structures on both sides only needs to ensure that there is no slippage and no falling off.

[0049] In a further embodiment of the present invention, the carbonic anhydrase is attached to the porous fiber membrane by a layer stacking method, specifically: based on the electrostatic adsorption characteristics of polyelectrolyte and carbonic anhydrase, polyelectrolyte solution and carbonic anhydrase solution of equal concentration are respectively prepared, and the porous fiber membrane 7 is placed in the solution in order for attachment. For example, the polyelectrolyte solution is polyethyleneimine PEI, polystyrene sulfonate sodium PSS and polyallylamine hydrochloride PAH, and the concentrations are all 1 mg / mL. The concentration of the carbonic anhydrase solution is also 1 mg / mL. The order of stacking attachment is PEI / PSS / PAH / [PSS / PAH / CA]3, where CA represents carbonic anhydrase, and the subscript 3 represents the number of layers of attached carbonic anhydrase.

[0050] The present invention also provides a method for preparing the microalgae direct air carbon capture intake device based on the layer stacking method with carbonic anhydrase attached, which is characterized by comprising the following steps:

[0051] Step 1: Cultivate a microalgae solution 2 and place it in a photobioreactor 1. The initial concentration of the microalgae solution 2 in the photobioreactor 1 is generally 0.1 g·L -1 .

[0052] Step 2: According to the above method, a porous fiber membrane 7 with carbonic anhydrase attached is prepared.

[0053] Step 3: Install the porous fiber membrane 7 with carbonic anhydrase attached to the outlet end of the air pump intake pipe 3 through the aforementioned installation assembly.

[0054] Step 4: connect the air pump inlet pipe 3 to the photobioreactor 1 , and immerse the outlet end of the air pump in the microalgae solution 2 .

[0055] Figure 6 The photobioreactor and air intake device of a runway pool used in an embodiment of the present invention are shown, wherein an intermediate partition is placed in the middle of the reactor to separate the microalgae solutions on both sides of the runway pool, the paddle wheel is connected to the motor through a shaft, and the microalgae solution is mixed by the uniform rotation of the paddle wheel, and the air intake membrane assembly proposed in the present invention is connected to the reactor through the air inlet of the air intake pipe and immersed in the microalgae solution.

[0056] Furthermore, the method for preparing the porous fiber membrane 7 with attached carbonic anhydrase of the present invention is described in more detail as follows:

[0057] 1) Prepare PSU / DMAc electrospinning membrane solution, add polysulfone PSU particles (MW ~ 20000, BSF3010) to N, N-dimethylacetamide (DMAc) at a solid mass fraction of 12-18wt.% (more preferably 15wt.%) to prepare membrane solution, and prepare 25mL of membrane solution for use. Put it into a glass reagent bottle, set the stirring temperature to 60°C in a constant temperature magnetic stirrer, and stir at 600rpm for 12 hours at a constant temperature until it is evenly dissolved. After stirring, let it stand overnight for degassing.

[0058] 2) Perform electrospinning in the laboratory using an electrospinning machine and a uniform injection pump. Use the prepared PSU / DMAc film-making solution, suck it into the syringe, connect the syringe, propulsion pump, catheter, and electrospinning needle in sequence, and wrap a 15cm wide aluminum foil on the drum as a carrier for spinning. The electrospinning voltage is 18kV, the distance between the needle and the drum is 10cm, the drum speed is 600rpm, and the spinning needle moves at a uniform speed in the horizontal direction of the drum width to spin the film. The film can be completed in about 6 hours. The flowchart of the attachment and film-making process of this experiment is shown below. Figure 7 as shown.

[0059] 3) Layer stacking method to attach carbonic anhydrase and polyelectrolyte. The PSU membrane prepared by electrospinning was peeled off from the loaded aluminum foil, and three polyelectrolyte solutions (1 g / mL, 50 mL for standby use) of polyethyleneimine (PEI), sodium polystyrene sulfonate (PSS) and polyallylamine hydrochloride (PAH) were prepared respectively, and the PEI / PSS / PAH / [PSS / PAH / CA] x The layers are stacked in the order of Figure 5 Carbonic anhydrase (CA) is attached to the prepared electrospinning membrane by using the principle of electrostatic adsorption, wherein x represents the number of layers of attached CA. After preliminary optimization experiments, 5 layers of attached CA are used in the present invention to ensure effective stability and durability.

[0060] 4) Carbonic anhydrase activity test. The activity of attached carbonic anhydrase was determined by the Wilbur-Anderson method. The PSU membrane attached with CA was immersed in 12.6 mL of buffer solution (Tris 50 mM, pH 8.3), and the ambient temperature was controlled at 4°C using an ice bath. 6 mL of supersaturated carbon dioxide aqueous solution was added, and the time for the pH value of the solution to drop from 8.3 to 7.3 was measured using a pH meter to evaluate the rate at which carbon dioxide was converted into bicarbonate in the solution.

[0061] According to the above embodiments, the present invention conducted a microalgae carbon fixation performance test experiment. Four control groups were set up through a control experiment, using group 1-PSU membrane attached with carbonic anhydrase, group 2-PSU membrane without attachment, group 3-air stone air intake assembly previously used in the laboratory, and group 4-air intake pipe direct air supply, respectively, for comparative evaluation of the carbon fixation effect of the air intake assembly attached with carbonic anhydrase in the present invention. The experimental results are as follows: Figure 8 It can be seen that after the carbonic anhydrase is attached, the auxiliary carbon fixation efficiency of the PSU membrane air intake assembly is increased by 105.6% compared with the control group with direct air intake pipe supply.

[0062] In summary, the present invention optimizes and improves the air intake component of the microalgae photobioreactor, utilizes the electrospinning method to deposit the polymer fiber on the nylon support structure, and then uses the layer stacking method to fix the carbonic anhydrase on the porous fiber membrane of the polymer by electrostatic adsorption, and uses a metal breathable material as a support, thereby effectively improving the CO2 solubility in the direct air carbon capture process, improving the problems of low mechanical strength and easy breakage of the porous fiber membrane in the traditional membrane air intake component, and effectively solving the problems of poor durability and easy loss of activity of the membrane material to which the carbonic anhydrase is attached, which is of great significance for improving the capture efficiency of direct air carbon capture.

[0063] The above embodiments are only for illustrating the technical solutions and laboratory application characteristics of the present invention, and their purpose is to explain the content and technical solutions of the invention in detail for easy understanding, and they cannot be used to limit the protection scope of the present invention. All equivalent changes made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A microalgae direct air carbon capture air intake device based on the layer stacking method with carbonic anhydrase attached, comprising a photobioreactor (1), an air pump air intake pipe (3) and an air intake membrane assembly (4), wherein the photobioreactor (1) contains a microalgae solution (2), and the air intake membrane assembly (4) is installed at the outlet end of the air pump air intake pipe (3) and immersed in the microalgae solution (2), characterized in that: The air intake membrane assembly (4) is composed of a mounting assembly and a porous fiber membrane (7) with carbonic anhydrase attached thereto; the porous fiber membrane (7) with carbonic anhydrase attached thereto is mounted on the outlet end of the air pump air intake pipe (3) through the mounting assembly, so that the intake air passes through the porous fiber membrane (7) with carbonic anhydrase attached thereto and then enters the microalgae solution (2).

2. The microalgae direct air carbon capture intake device based on layer stacking method with carbonic anhydrase attached according to claim 1, characterized in that: The installation assembly comprises: a hollow fixing nut (5), a first metal breathable fixing structure (6), a second metal breathable fixing structure (8) and a hollow fixing nut (9); the porous fiber membrane (7) attached with carbonic anhydrase is clamped between the first metal breathable fixing structure (6) and the second metal breathable fixing structure (8), and is installed at the end of the hollow fixing nut (5); the hollow fixing nut (5) and the hollow fixing nut (9) are assembled into one and installed at the outlet end of the air pump intake pipe (3).

3. The microalgae direct air carbon capture intake device based on layer stacking method with carbonic anhydrase attached according to claim 2, characterized in that: The first metal breathable fixing structure (6) and the second metal breathable fixing structure (8) are composed of porous metal plates, the pore size of the porous metal plates is larger than the pore size of the porous fiber membrane (7), the first metal breathable fixing structure (6), the second metal breathable fixing structure (8) and the porous fiber membrane (7) are clamped by the stress between the hollow fixing nut (5) and the grooves on the hollow fixing nut (9), and the hollow fixing nut (5) and the hollow fixing nut (9) are connected by a threaded structure, and the air intake pipe is inflated in the hollow structure.

4. The microalgae direct air carbon capture intake device based on layer stacking method with carbonic anhydrase attached according to claim 1, 2 or 3, characterized in that: The porous fiber membrane (7) with carbonic anhydrase attached has a nylon support material as a substrate, uses an electrostatic spinning method to deposit polymer fibers on the substrate, prepares a polysulfone solution, performs electrostatic spinning, and attaches carbonic anhydrase and polyelectrolyte to both sides of the substrate on which the polymer fibers are deposited by a layer stacking method.

5. The microalgae direct air carbon capture intake device based on layer stacking method with carbonic anhydrase attached according to claim 4, characterized in that: The carbonic anhydrase is attached to the porous fiber membrane (7) by a layer stacking method, specifically: based on the electrostatic adsorption characteristics of polyelectrolyte and carbonic anhydrase, a polyelectrolyte solution and a carbonic anhydrase solution with equal concentrations are respectively prepared, and the porous fiber membrane (7) is placed in the solutions in order for attachment.

6. The microalgae direct air carbon capture intake device based on layer stacking method with carbonic anhydrase attached according to claim 5, characterized in that: The polyelectrolyte solutions are polyethyleneimine (PEI), sodium polystyrene sulfonate (PSS) and polyallylamine hydrochloride (PAH), and the order of stacking and attachment is PEI / PSS / PAH / [PSS / PAH / CA]3, wherein CA represents carbonic anhydrase, and the superscript 3 represents the number of layers to which the carbonic anhydrase is attached.

7. The method for preparing the microalgae direct air carbon capture intake device based on the layer stacking method with carbonic anhydrase attached according to claim 1, characterized in that: include: Cultivating a microalgae solution (2) and placing it in a photobioreactor (1); preparing a porous fiber membrane with carbonic anhydrase attached thereto (7); The porous fiber membrane (7) attached with carbonic anhydrase is installed at the outlet end of the air pump intake pipe (3) by means of an installation assembly; The air pump inlet pipe (3) is connected to the photobioreactor (1), and its outlet end is immersed in the microalgae solution (2).

8. The preparation method according to claim 7, characterized in that: The preparation method of the porous fiber membrane (7) attached with carbonic anhydrase is as follows: Step 1, preparing electrospinning film-making solution; Step 2, performing electrospinning on the surface of the nylon fiber membrane; Step 3: attach carbonic anhydrase and polyelectrolyte by layer stacking method.

9. The preparation method according to claim 8, characterized in that: The preparation process of the electrospinning film-making solution is as follows: Add polysulfone PSU particles at a solid mass fraction of 12-18wt.% to N,N-dimethylacetamide to prepare a membrane-making solution, stir thoroughly until dissolved evenly, and let stand overnight for degassing treatment after stirring.

10. The preparation method according to claim 8, characterized in that: The layer stacking method attaches carbonic anhydrase and polyelectrolyte as follows: The electrospun membrane was peeled off from the support and three polyelectrolyte solutions of polyethyleneimine (PEI), sodium polystyrene sulfonate (PSS) and polyallylamine hydrochloride (PAH) were prepared according to the formula of PEI / PSS / PAH / [PSS / PAH / CA] x The layers are stacked in the order of , and carbonic anhydrase (CA) is attached to the prepared electrospinning membrane by utilizing the principle of electrostatic adsorption, where x represents the number of layers of attached CA.

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