Hydrophobic / carbon dioxide-philic molybdenum disulfide nanosheet as well as preparation method and application thereof

Abstract

The invention discloses a hydrophobic / carbon dioxide-philic molybdenum disulfide nanosheet as well as a preparation method and application thereof, and belongs to the technical field of nano materials and oil and gas exploitation, the preparation method comprises the following steps: preparing a MoS2 nanosheet by adopting a hydrothermal synthesis method in combination with a pulse laser crushing technology; the preparation method comprises the following steps: sequentially carrying out aminated ethylene oxide / propylene oxide surfactant modification on a MoS2 nanosheet, and covalently immobilizing cyanobacteria carbonic anhydrase on the surface of the nanosheet by utilizing 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide / N-hydroxysuccinimide crosslinking, so as to prepare a CA-EO / PO-MoS2 compound with double functions of hydrophobicity and CO2 affinity; the preparation method comprises the following steps: adding the CA-EO / PO-MoS2 compound into formation water, adding sophorolipid into the formation water, and carrying out auxiliary ultrasonic treatment to realize long-term stable dispersion of nanosheets, so as to prepare a CA-EO / PO-MoS2 dispersion liquid. According to the method, the CO2 oil displacement efficiency and the environmental friendliness of the shale reservoir are remarkably improved through the technologies of precise size control, composite hydrophobic layer construction, bio-enzyme functionalization and biological dispersant stabilization.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials and oil and gas extraction, and in particular relates to hydrophobic / carbon dioxide-philic molybdenum disulfide nanosheets and a preparation method and application thereof. Background Art

[0002] In the field of shale oil and gas extraction, CO2 flooding technology has attracted much attention due to its dual advantages of improving recovery and carbon sequestration. However, its practical application still faces multiple technical bottlenecks: first, the solubility efficiency of CO2 in crude oil is low, which is prone to viscous fingering and premature gas channeling, resulting in a decrease in displacement efficiency; second, the storage stability of CO2 in the formation is poor, and the long-term storage rate is generally less than 70%, which poses leakage risks and environmental hazards.

[0003] Traditional nanomaterials for oil displacement (such as silica, alumina, etc.) are difficult to adapt to the characteristics of shale reservoirs due to size and function limitations: First, the nano-scale pores of shale (10-50nm) are extremely sensitive to the size of the material. Currently, the thickness of molybdenum disulfide (MoS2) nanosheets is generally greater than 1nm, which can easily clog the pores during displacement, resulting in a permeability drop of more than 30%; secondly, the existing materials have a single function. Hydrophobic materials (such as silane-modified SiO2) lack CO2 adsorption capacity, while CO2-philic materials (such as amino-functionalized materials) are too hydrophilic to aggravate water absorption. The locking effect makes it difficult for the two to synergistically improve oil recovery efficiency. Furthermore, the high temperature (>60°C) and high salinity (>10,000 ppm) environment of shale reservoirs destabilizes the dispersion stability of nanoparticles. Conventional surfactants (such as sodium dodecyl sulfate (SDS)) become ineffective due to the compression of the double layer by salt ions. Nanosheets aggregate and grow to hundreds of nanometers in size, further blocking pores and reducing displacement fluid fluidity. Furthermore, traditional chemical modification processes rely on toxic reagents such as fluorosilanes and coupling agents, generating hazardous waste during production and contradicting the trend of green oil and gas extraction. To address these issues, recent research has attempted to improve material performance through composite modification. Polyethyleneimine-modified MoS2 has been proposed to enhance CO2 adsorption, but the modified layer thickness is too large (>2 nm) and does not address the issue of high-temperature agglomeration. Other studies have used amphiphilic polymers to coat nanoparticles, but the material size remains above 20 nm, preventing it from penetrating the nanopores of shale. Meanwhile, the rise of biotechnology in materials engineering has provided new avenues for green modification. For example, carbonic anhydrase, secreted by cyanobacteria, can efficiently catalyze CO2 hydration. However, although the bio-nanocomposite strategy has been proposed, its practical application is still limited by immobilization efficiency and stability. For example, the enzyme loading capacity by physical adsorption method is usually less than 100 mg / g, and it is easy to fall off or inactivate in high temperature, high mineralization environment and under shear.

[0004] In summary, developing an environmentally friendly nanomaterial that is ultra-small in size, has dual hydrophobic and CO2-affinity functions, is anti-agglomeration, and has become a core challenge in upgrading CO2 flooding technology in shale reservoirs. Summary of the Invention

[0005] In response to the above technical problems, the present invention proposes hydrophobic / CO2-philic molybdenum disulfide nanosheets and their preparation method and application. Through precise size control, composite hydrophobic layer construction, bio-enzyme functionalization and bio-dispersant stabilization technology, it solves the problems of agglomeration and blockage, single function and environmental pollution of traditional materials in shale reservoirs.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheets comprises the following steps:

[0008] MoS2 nanosheets were prepared by hydrothermal synthesis combined with pulsed laser fragmentation technology;

[0009] The MoS2 nanosheets were sequentially aminated with ethylene oxide / propylene oxide (EO / PO) surfactants (C 16 -EO5-PO 10 -C 16 -NH2) modification and EDC / NHS (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide / N-hydroxysuccinimide) cross-linking were used to covalently immobilize cyanobacterial carbonic anhydrase (CA) on the surface of the nanosheets to prepare a CA-EO / PO-MoS2 composite with both hydrophobic and CO2-philic dual functions.

[0010] The CA-EO / PO-MoS2 complex is added to formation water, and sophorolipids are added thereto, and assisted ultrasonic treatment is performed to achieve long-term stable dispersion of nanosheets to prepare a dispersion containing CA-EO / PO-MoS2 nanosheets, wherein the CA-EO / PO-MoS2 nanosheets are the anti-agglomeration hydrophobic / co2philic molybdenum disulfide nanosheets.

[0011] Beneficial effects: The present invention proposes a method for preparing anti-agglomeration hydrophobic-CO2-philic bifunctional molybdenum disulfide (MoS2) nanosheets. Through a series of precise control and functionalization steps, excellent performance improvement and application effects are achieved, specifically:

[0012] 1. Controllable Synthesis and Size Control of MoS2 Nanosheets: This study successfully prepared MoS2 nanosheets with a lateral size of approximately 9 nanometers and monolayer to submonolayer thicknesses using a hydrothermal synthesis method combined with pulsed laser fragmentation. This method overcomes the size control limitations of traditional exfoliation methods and ensures high uniformity and consistency of the nanosheets.

[0013] 2. Dual functional modification strategy: The present invention adopts amino EO / PO surfactant (C 16-EO5-PO 10 -C 16 -NH2) was used to modify MoS2 nanosheets, significantly improving their oleophobicity. The crude oil contact angle increased from ~57° to ~138°, greatly enhancing the hydrophobicity of the nanosheets. Cyanobacterial carbonic anhydrase (CA) was then covalently fixed to the surface of the nanosheets using EDC / NHS cross-linking technology, giving the material a high affinity and catalytic activity for CO2, thereby enhancing its efficiency and selectivity in the CO2 flooding process.

[0014] 3. Anti-agglomeration and dispersion stability control: In simulated formation water with a salinity of 10,000 ppm, the present invention effectively prevents the aggregation of nanosheets by adding sophorolipids and performing auxiliary ultrasonic treatment, achieving long-term stable dispersion of nanosheets in complex environments. This step is crucial to ensuring the high efficiency and durability of the nanosheets in practical applications.

[0015] 4. Synergistic CO2 flooding and storage: The functionalized CA-EO / PO-MoS2 nanosheets not only increase oil permeability but also reduce water permeability, optimizing the oil-water mobility ratio and significantly improving oil recovery efficiency. Furthermore, the presence of cyanobacterial carbonic anhydrase (CA) promotes CO2 hydration, further enhancing CO2 storage and achieving synergistic CO2 recovery and storage.

[0016] In summary, the preparation method provided by the present invention successfully prepared a MoS2 nanosheet composite with both hydrophobic and CO2-philic properties through precise synthesis, functional modification and dispersion stability regulation, significantly improving its comprehensive performance in the CO2 oil recovery process.

[0017] Optionally, the amino EO / PO surfactant is C 16 -EO5-PO 10 -C 16 -NH2; among them,

[0018] C 16 : represents two hexadecyl hydrophobic chains, located at both ends of the molecule;

[0019] EO5: represents a hydrophilic segment composed of five ethylene oxide (EO) units;

[0020] PO 10 : represents a lipophilic segment composed of ten propylene oxide (PO) units;

[0021] NH2: represents an amino functional group, connected to one end of the molecule.

[0022] Optionally, the method for preparing the anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheets specifically comprises the following steps:

[0023] (1) adding thioacetamide to an aqueous solution of ammonium heptamolybdate, adjusting the pH, and stirring uniformly to prepare a precursor solution; then subjecting the precursor solution to a hydrothermal synthesis reaction, a pulsed laser fragmentation treatment, and drying to obtain MoS2 nanosheets;

[0024] (2) preparing the MoS2 nanosheets into a MoS2 dispersion, adding an amino EO / PO surfactant thereto, stirring evenly, and then centrifuging and washing to obtain an NH2-EO / PO-MoS2 complex;

[0025] (3) subjecting the NH2-EO / PO-MoS2 complex to an oscillating reaction with a CA enzyme under the action of a cross-linking agent to obtain a CA-EO / PO-MoS2 complex;

[0026] (4) adding the CA-EO / PO-MoS2 complex and sophorolipids to formation water, stirring evenly, and then ultrasonically treating and centrifuging to obtain a dispersion containing CA-EO / PO-MoS2 nanosheets.

[0027] Furthermore, the mass ratio of ammonium heptamolybdate to the thioacetamide in the ammonium heptamolybdate aqueous solution is (4.0-4.8): (1.0-1.2).

[0028] Furthermore, the pH is 3.5±0.2.

[0029] Furthermore, the conditions during the hydrothermal synthesis reaction are:

[0030] Heat the sample to 180±2°C at a rate of 1-3°C / min, then keep at this temperature for 24 hours and then cool naturally to room temperature.

[0031] Furthermore, the conditions of the pulse laser fragmentation process are:

[0032] The pulse energy is 180-220 mJ / pulse; the frequency is 8-12 Hz; the spot diameter is 1.5-2.5 mm; and the treatment time is 30 minutes.

[0033] Furthermore, in step (2), the ratio of the amount of the MoS2 dispersion to the amino EO / PO surfactant is: 1.0 L: (0.4-0.6) g;

[0034] The concentration of the MoS2 dispersion is 0.8-1.2 mg / mL.

[0035] Further, the stirring process in step (2) is:

[0036] The mixture was stirred magnetically at 600 rpm at 60°C for 6 hours.

[0037] Further, the extraction process of the CA enzyme is:

[0038] Cyanobacteria were cultured in BG-11 medium until the middle of the logarithmic growth phase (OD 730 =1.2), the cells were collected by centrifugation, and then subjected to ultrasonic disruption and ammonium sulfate graded precipitation to obtain a crude enzyme solution, which is the CA enzyme.

[0039] Furthermore, each liter of the BG-11 basal medium includes the following components:

[0040] Sodium nitrate (NaNO3) 1.5g, dipotassium hydrogen phosphate (K2HPO4) 0.04g, magnesium sulfate (MgSO4·7H2O) 0.075g; add 1mL of the finished trace element solution;

[0041] The finished trace element solution contains the following components: 1.0 g / L disodium edetate, 0.6 g / L ammonium ferric citrate, 286 mg / L boric acid, 181 mg / L manganese chloride, 22 mg / L zinc sulfate, 39 mg / L sodium molybdate, 7.9 mg / L copper sulfate, and 4.9 mg / L cobalt nitrate.

[0042] Furthermore, the fragmentation buffer used in the ultrasonic fragmentation process is a Tris-HCl fragmentation buffer containing 1 mM phenylmethylsulfonyl fluoride.

[0043] Furthermore, the usage ratio of the NH2-EO / PO-MoS2 complex, cyanobacterial carbonic anhydrase and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide crosslinker is 1.0 g:(0.15-0.25) g:(8-12) mM.

[0044] Furthermore, the oscillation reaction process is: oscillation reaction at 37° C. for 6 hours.

[0045] Furthermore, the formation water is simulated formation water with a pH of 7.0±0.2 and a salinity of 10,000 ppm; the simulated formation water includes the following components:

[0046] 8,500mg / LNa + 、1,200mg / L Ca 2+ and 300mg / L Cl - .

[0047] Furthermore, the usage ratio of the formation water, CA-EO / PO-MoS2 complex and sophorolipid is: 1L: (0.8-1.2) g: (4.0-6.0) mg.

[0048] Furthermore, the conditions during the ultrasonic treatment in step (4) are: continuous ultrasonic treatment at a power of 100 W for 10 minutes.

[0049] An anti-agglomeration hydrophobic / carbon dioxide-philic molybdenum disulfide nanosheet is prepared by the above preparation method.

[0050] The application of the above-mentioned anti-agglomeration hydrophobic / co2-philic molybdenum disulfide nanosheets in the field of shale oil and gas extraction.

[0051] Compared with the prior art, the present invention has the following advantages and technical effects:

[0052] This invention discloses the use of anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheets as an oil-displacing agent. Through the innovative design of "precise structural control - dual functional modification - bio-enzyme synergy", it breaks through the limitations of traditional technology and realizes the high performance of the material through the synergistic steps:

[0053] (1) Size-controlled MoS2 nanosheets: The nanosheets are less than 0.5 nm thick and fit into the pores of shale;

[0054] (2) Hydrophobic-CO2-philic dual functionalization: constructing an EO / PO surfactant-modified MoS2 hydrophobic layer and a cyanobacterial carbonic anhydrase CO2-philic layer;

[0055] (3) Salt-resistant dispersion and enzyme activity protection: Sophorolipids are used to inhibit aggregation in high temperature and high salt environments;

[0056] (4) Use bio-based raw materials (cyanobacteria enzymes, sophora biosurfactants) and no toxic chemical reagents.

[0057] In summary, the present invention significantly improves the efficiency and environmental friendliness of CO2 flooding in shale reservoirs through multi-dimensional innovation. The specific beneficial effects are as follows:

[0058] Functional synergy breakthrough: Through the gradient modification of the hydrophilic / hydrophobic long chains of EO / PO and the CO2-philic layer of cyanobacterial carbonic anhydrase (CA), the dual functional synergy of hydrophobicity and CO2 adsorption-catalysis is achieved, breaking through the technical bottleneck of the single function of traditional materials.

[0059] Environmental adaptability: The introduction of sophorolipid biodispersants solves the problem of reservoir blockage caused by nanoparticle agglomeration.

[0060] Green process: Bio-based technologies such as cyanobacteria enzyme extraction and sophorolipid dispersants are used to replace traditional toxic reagents such as fluorosilane and SDS (sodium dodecyl sulfate), which meets the green mining needs under the background of carbon neutrality. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0062] Figure 1 (a) A scanning electron microscope (SEM) image and (b) a transmission electron microscope (TEM) image of the MoS2 nanosheet sample prepared in Example 1 of the present invention;

[0063] Figure 2 Atomic force microscopy (AFM) image (a) and statistical graph (b) of the MoS2 nanosheet sample prepared in Example 1 of the present invention;

[0064] Figure 3 Contact angle analysis diagram of the unmodified MoS2 nanosheet sample (a) and the MoS2 nanosheet sample modified with EO / PO surfactant (b) prepared in Example 1 of the present invention;

[0065] Figure 4 Schematic diagram of the enzyme immobilization reaction mechanism in Example 1 of the present invention;

[0066] Figure 5 This is a dynamic scanning curve diagram of reference transmitted light of the dispersion containing CA-EO / PO-MoS2 nanosheets prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0067] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0068] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0069] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0070] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0071] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0072] Unless otherwise specified, the "room temperature" in the present invention refers to 20-30°C.

[0073] The raw materials used in the present invention are all purchased from the market. 16 -EO5-PO 10 -C 16 -NH2 was purchased from Zhejiang Royal Madrid Science and Technology Co., Ltd.; EDC / NHS cross-linking agent was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0074] The technical solution of the present invention is further illustrated by the following examples.

[0075] Example 1

[0076] A method for preparing anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheets comprises the following steps:

[0077] 1. Preparation and size control of MoS2 nanosheets

[0078] Step 1.1: Precursor preparation

[0079] Use a graduated cylinder to measure 450mL of deionized water and pour it into a 1L beaker. First weigh 4.41g of ammonium heptamolybdate, slowly add it to the water, turn on the magnetic stirrer (500rpm), and stir until completely dissolved. Then weigh 1.07g of thioacetamide and add it to the solution in batches. Continue stirring for 15 minutes until the solution is transparent and uniform. Add 0.1M (about 15mL) hydrochloric acid dropwise until the pH stabilizes at 3.5±0.2. If the solution volume is reduced due to acid addition, make up to 500mL with the reserved 50mL of deionized water and stir again for 5 minutes to ensure uniformity. Transfer the prepared solution to a 500mL polytetrafluoroethylene-lined reactor and seal it.

[0080] Step 1.2: Hydrothermal synthesis

[0081] Transfer the prepared pH 3.5 mixed solution to a 100mL polytetrafluoroethylene liner, ensuring the liquid level does not exceed 80mL. Place the liner in a stainless steel jacket and tighten the sealing cap to ensure no leaks. Place the reactor in an oven preheated to room temperature with the door closed. Set the oven to heat to 180±2°C at 2°C / min and keep warm for 24 hours. After the reaction is completed, cool naturally to room temperature. Open the reactor and transfer the reaction solution to a 50mL centrifuge tube precooled to 4°C. Centrifuge at 8000rpm for 15 minutes and discard the supernatant. Resuspend the precipitate in a mixture of ethanol and water (volume ratio 1:1) and ultrasonically disperse for 5 minutes. Repeat the centrifugation at 8000rpm for 10 minutes and repeat the washing step three times to precipitate the crude MoS2 product.

[0082] Step 1.3: Pulsed Laser Fragmentation

[0083] Equipment parameters: Nd:YAG solid-state laser (wavelength 1064 nm, near-infrared band); pulse energy 200 mJ / pulse (single pulse energy); frequency 10 Hz; spot diameter 2 mm; treatment time 30 minutes.

[0084] The crude MoS2 product was dispersed in deionized water at a concentration of 1 mg / mL (1:1) and sonicated (150 W, 20 kHz) for 30 minutes until initially dispersed. The dispersion was then transferred to a quartz bath with a liquid level of 5 cm. The laser cooling system was activated (circulating water temperature ≤ 20°C) and the laser was preheated for 10 minutes. The optical path was adjusted so that the laser beam was perpendicular to the center of the bath, with the spot covering the center of the liquid surface. The laser was activated and treatment continued for 30 minutes, with magnetic stirring at 200 rpm to maintain fluidity. After laser treatment, the dispersion was centrifuged at 5000 rpm for 5 minutes, and the supernatant (containing nanosheets <10 nm) was collected. The centrifugation and supernatant collection steps were repeated twice to obtain a dispersion of uniformly sized nanosheets. 10 μL of the dispersion was added to a carbon-supported copper grid and dried at room temperature to prepare TEM / SEM samples. The accelerating voltage was 200 kV for TEM and 10 kV for SEM. 5 μL of the dispersion was added to a freshly cleaved mica sheet and dried at room temperature to prepare AFM samples.

[0085] Figure 1 (a) is a scanning electron microscope (SEM) image and (b) is a transmission electron microscope (TEM) image of the MoS2 nanosheet sample prepared in Example 1 of the present invention; it can be seen from the figure that the lateral size of the MoS2 nanosheet sample prepared in Step 1 of Example 1 of the present invention is ~9nm, and the longitudinal size is ~7nm.

[0086] Figure 2The atomic force microscope (AFM) image (a) and statistical graph (b) of the AFM sample prepared in Example 1 of the present invention can be seen from the figure that the thickness of the MoS2 nanosheet sample is monolayer to sub-monolayer, that is, the thickness of the monolayer MoS2 is 0.4±0.2nm, and the theoretical thickness of the monolayer MoS2 is 0.65nm. The measured value is lower due to the substrate adsorption effect.

[0087] 2. Hydrophobic functionalization

[0088] 1.0 g of MoS2 nanosheet sample was added to 1 L of anhydrous ethanol and ultrasonicated (150 W, 20 kHz) for 30 minutes to form a uniform dispersion (concentration 1 mg / mL); 0.5 g of amino EO / PO surfactant C was weighed. 16 -EO5-PO 10 -C 16 -NH2, slowly added to the dispersion, stirred at 600 rpm at 60 ° C for 6 hours, so that the hydrophobic alkyl chain (C 16 ) adsorbed to the MoS2 surface through van der Waals forces, while the EO / PO chain segments extended outward and the terminal amino groups (-NH2) were exposed; centrifuged at 10,000 rpm for 10 minutes, and the supernatant (containing unreacted surfactant) was discarded; washed with 50 mL of anhydrous ethanol and centrifuged three times to obtain an NH2-EO / PO-MoS2 complex.

[0089] To verify the hydrophobicity enhancement effect of EO / PO surfactant-modified MoS2 nanosheets (i.e., NH2-EO / PO-MoS2 composites) in a CO2 atmosphere, the hydrophobicity was quantified by measuring the contact angle of crude oil droplets on the material surface. First, a silicon wafer was ultrasonically cleaned in acetone for 10 minutes to remove residual organic matter from the surface. The wafer was then ultrasonically cleaned in ethanol for 10 minutes to remove residual acetone. The wafer was rinsed three times with ultrapure water and dried with nitrogen. Finally, the surface was treated in an oxygen plasma cleaner for 5 minutes to enhance surface hydrophilicity. 10 mg of the EO / PO-MoS2 composite was dispersed in 1 mL of anhydrous ethanol and ultrasonically treated (150 W, 20 kHz) for 10 minutes. The dispersion was then evenly added dropwise to the surface of the silicon wafer. The coated wafer was then dried in a vacuum oven at 60°C for 2 hours to remove the solvent.

[0090] The coated silicon wafer was fixed on the sample stage of the contact angle meter; the test chamber was sealed, evacuated to -0.1MPa, and filled with CO2 to normal pressure to simulate the oil displacement environment; about 5μL of water was drawn with a micro syringe and dripped vertically onto the surface of the silicon wafer; after the droplet was formed and stabilized, the droplet morphology was photographed at a side angle using a contact angle meter.

[0091] Figure 3The contact angle analysis diagram of the unmodified MoS2 nanosheets (a) and the MoS2 nanosheets modified with EO / PO surfactants (b) prepared in Example 1 of the present invention; Figure 3 It can be seen that EO / PO surfactant modification increases the contact angle of MoS2 nanosheets from ~57° to ~138°, significantly enhancing the hydrophobicity.

[0092] 3. Microbial CO2-affinity functionalization

[0093] Step 3.1: Cyanobacteria culture and enzyme extraction

[0094] Highly active carbonic anhydrase (CA) was obtained through cyanobacteria (Synechococcus sp. PCC 7002) cultivation and enzyme extraction process.

[0095] Preparation of BG-11 basal medium: Dissolve 1.5 g of sodium nitrate (NaNO3), 0.04 g of potassium dihydrogen phosphate (K2HPO4), and 0.075 g of magnesium sulfate (MgSO4·7H2O) in 900 mL of deionized water, stirring magnetically at 500 rpm until completely dissolved; add 1 mL of the finished trace element solution and make up to 1 L of deionized water; adjust the pH to 7.8 ± 0.2; aliquot into 500 mL conical flasks, autoclave at 120°C for 20 minutes, and cool until ready for use.

[0096] Take 50 μL of cyanobacteria liquid from the bacterial preservation tube and inoculate it into 50 mL of BG-11 liquid culture medium. Pre-culture it in a normal light incubator for 3 days (30°C, light intensity 50 μmol photons / m 2 / s, continuous light). The activated bacterial solution was transferred to 1L sterile BG-11 medium at a 10% inoculum volume and aerated with a mixed gas containing 5% CO2 (CO2 / air, v / v) at a ventilation rate of 0.1vvm. Samples were taken every 12 hours and the absorbance at 730nm was measured using a UV spectrophotometer until the middle of the logarithmic growth phase (OD 730 =1.2).

[0097] Transfer the culture to a 50 mL centrifuge tube and centrifuge at 8000 × g for 15 minutes at 4°C. Discard the supernatant and gently resuspend the cells in pre-chilled phosphate buffer. Repeat the centrifugation wash twice to obtain a wet bacterial slurry. Prepare 50 mM Tris-HCl disruption buffer containing 1 mM phenylmethylsulfonyl fluoride. Mix the bacterial slurry with the disruption buffer in a 1:5 (w / v) ratio and chill on ice. Ultrasonicate at 300 W for 10 minutes. The whole process of the fragmentation was kept in an ice bath to maintain the sample temperature ≤ 10°C; the fragmentation solution was centrifuged at 12,000 × g for 20 minutes at 4°C, the supernatant was collected, and ammonium sulfate powder was slowly added to the crude enzyme solution (0°C ice bath) while stirring; ammonium sulfate was added to the supernatant to a final saturation of 60%; stirring for 30 minutes, standing and centrifuging steps, standing at 4°C for 2 hours; centrifugation at 12,000 × g for 20 minutes at 4°C, and the precipitate was collected; the precipitate was dissolved in Tris-HCl buffer (50mM, pH 8.0) to obtain CA crude enzyme solution. The crude enzyme solution was loaded into a desalting column to remove residual ammonium sulfate to obtain CA enzyme;

[0098] Step 3.2: EDC / NHS-mediated enzyme immobilization

[0099] 1.0 g of NH2-EO / PO-MoS2 complex was mixed with 0.2 g of CA enzyme, and 10 mM EDC / NHS crosslinker (dissolved and diluted in pH 6 phosphate buffer) was added. The reaction was shaken at 37°C for 6 hours. The CA enzyme was immobilized on the surface of the nanosheet through carboxyl-amino covalent coupling. After centrifugation (10,000 rpm, 10 minutes) to remove the free enzyme, the precipitation was washed three times (pH 7.4 phosphate buffer) to obtain the CA-EO / PO-MoS2 complex.

[0100] Figure 4 Schematic diagram of the enzyme immobilization reaction mechanism in Example 1 of the present invention; it can be seen that in the covalent coupling reaction, the EO / PO chain still exists as a structural part of the surfactant and is not decomposed or removed; the amino group is only a functional group at the end of the surfactant molecule, which is used for enzyme immobilization. The main function of the EO / PO chain is to maintain the dispersibility and hydrophobicity of the nanosheets.

[0101] 4. Anti-agglomeration and dispersion control

[0102] Prepare simulated formation water with a mineralization of 10,000 ppm, containing 8,500 mg / L Na + (8.5g / L NaCl), 1200mg / L Ca 2+(2.94 g / L CaCl2·2H2O) and 300 mg / L Cl-, and the pH was adjusted to 7.0±0.2 with 0.1 M HCl / NaOH. 1.0 g of the CA-EO / PO-MoS2 complex was added to 1 L of the simulated formation water and pre-dispersed at 500 rpm for 10 minutes. Then, 5.0 mg of sophorolipid (purity ≥95%, representing 0.5 wt% of the complex mass) was added and stirred for 5 minutes for preliminary mixing. Ultrasonic treatment was performed continuously at 100 W for 10 minutes using a probe-type ultrasonic processor, maintaining the solution temperature below 25°C. The probe was immersed 1 cm below the liquid surface and moved at a constant speed to ensure uniform dispersion. After sonication, the dispersion was centrifuged at 5000 rpm at room temperature for 5 minutes. The trace precipitate at the bottom was discarded, and the supernatant was collected to obtain a stable dispersion containing CA-EO / PO-MoS2 nanosheets.

[0103] Figure 5 This is a dynamic scanning curve diagram of the reference transmitted light of the CA-EO / PO-MoS2 nanosheet dispersion prepared in Example 1 of the present invention. It can be seen from the figure that within the scanning period, the variation amplitude of the transmitted light intensity is extremely small, and the curve is almost parallel to the time axis.

[0104] Example 2

[0105] A method for preparing anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheets comprises the following steps:

[0106] 1. Preparation and size control of MoS2 nanosheets

[0107] Step 1.1: Precursor preparation

[0108] Use a graduated cylinder to measure 450mL of deionized water and pour it into a 1L beaker. Weigh 4.0g of ammonium heptamolybdate, slowly add it to the water, turn on the magnetic stirrer (500rpm), and stir until completely dissolved. Then weigh 1.0g of thioacetamide and add it to the solution in batches. Continue stirring for 15 minutes until the solution is transparent and uniform. Add 0.1M (about 14mL) hydrochloric acid dropwise until the pH stabilizes at 3.5±0.2. If the solution volume is reduced due to acid addition, make up to 500mL with the reserved 50mL deionized water and stir again for 5 minutes to ensure uniformity. Transfer the prepared solution to a 500mL polytetrafluoroethylene-lined reactor and seal it.

[0109] Step 1.2: Hydrothermal synthesis

[0110] Transfer the prepared pH 3.5 mixed solution to a 100mL polytetrafluoroethylene liner, ensuring the liquid level does not exceed 80mL. Place the liner in a stainless steel jacket and tighten the sealing cap to ensure no leaks. Place the reactor in an oven preheated to room temperature with the door closed. Set the oven to heat to 180°C at 1°C / min and hold for 24 hours. After the reaction is complete, cool naturally to room temperature. Open the reactor and transfer the reaction solution to a 50mL centrifuge tube precooled to 4°C. Centrifuge at 8000 rpm for 15 minutes and discard the supernatant. Resuspend the precipitate in a mixture of ethanol and water (1:1 volume ratio) and ultrasonically disperse for 5 minutes. Repeat the centrifugation at 8000 rpm for 10 minutes and the washing step three times to precipitate the crude MoS2 product.

[0111] Step 1.3: Pulsed Laser Fragmentation

[0112] Equipment parameters: Nd:YAG solid-state laser (wavelength 1064 nm, near-infrared band); pulse energy 180 mJ / pulse (single pulse energy); frequency 8 Hz; spot diameter 1.5 mm; treatment time 30 minutes.

[0113] The TEM / SEM and AFM sample preparation methods are the same as in Example 1.

[0114] 2. Hydrophobic functionalization

[0115] 0.8 g of MoS2 nanosheet sample was added to 1 L of anhydrous ethanol and ultrasonicated for 30 minutes to form a uniform dispersion (concentration 0.8 mg / mL); 0.4 g of amino EO / PO surfactant C was weighed. 16 -EO5-PO 10 -C 16 -NH2, slowly added to the dispersion, stirred at 600 rpm at 60 ° C for 6 hours, so that the hydrophobic alkyl chain (C 16 ) adsorbed to the MoS2 surface through van der Waals forces, while the EO / PO chain segments extended outward and the terminal amino groups (-NH2) were exposed; centrifuged at 10,000 rpm for 10 minutes, and the supernatant (containing unreacted surfactant) was discarded; washed with 50 mL of anhydrous ethanol and centrifuged three times to obtain an NH2-EO / PO-MoS2 complex.

[0116] The experimental method for verifying the hydrophobicity enhancement effect of EO / PO surfactant-modified MoS2 nanosheets (i.e., NH2-EO / PO-MoS2 complex) in a CO2 atmosphere is the same as that in Example 1.

[0117] 3. Microbial CO2-affinity functionalization

[0118] Step 3.1: The process of cyanobacteria cultivation and enzyme extraction is the same as that in Example 1.

[0119] Step 3.2: EDC / NHS-mediated enzyme immobilization

[0120] 1.0 g of NH2-EO / PO-MoS2 complex was mixed with 0.15 g of CA enzyme, and 8 mM EDC / NHS crosslinker (dissolved and diluted in pH 6 phosphate buffer) was added. The reaction was shaken at 37°C for 6 hours. The CA enzyme was immobilized on the surface of the nanosheet through carboxyl-amino covalent coupling. After centrifugation (10,000 rpm, 10 minutes) to remove the free enzyme, the precipitation was washed three times (pH 7.4 phosphate buffer) to obtain the CA-EO / PO-MoS2 complex.

[0121] 4. Anti-agglomeration and dispersion control

[0122] Prepare simulated formation water with a mineralization of 10,000 ppm, containing 8,500 mg / L Na + (8.5g / L NaCl), 1200mg / L Ca 2+ (2.94 g / L CaCl2·2H2O) and 300 mg / L Cl-, and the pH was adjusted to 7.0±0.2 with 0.1 M HCl / NaOH. 0.8 g of the CA-EO / PO-MoS2 complex was added to 1 L of the simulated formation water and pre-dispersed at 500 rpm for 10 minutes. 4.0 mg of sophorolipid was then added and stirred for 5 minutes for preliminary mixing. Ultrasonication was then performed continuously at 100 W for 10 minutes using a probe-type ultrasonic processor, maintaining the solution temperature below 25°C. The probe was immersed 1 cm below the liquid surface and moved at a constant speed to ensure uniform dispersion. After sonication, the dispersion was centrifuged at 5000 rpm at room temperature for 5 minutes. The trace precipitate at the bottom was discarded, and the supernatant was collected to obtain a stable dispersion containing CA-EO / PO-MoS2 nanosheets.

[0123] Example 3

[0124] A method for preparing anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheets comprises the following steps:

[0125] 1. Preparation and size control of MoS2 nanosheets

[0126] Step 1.1: Precursor preparation

[0127] Use a graduated cylinder to measure 450mL of deionized water and pour it into a 1L beaker. Weigh 4.8g of ammonium heptamolybdate, slowly add it to the water, turn on the magnetic stirrer (500rpm), and stir until completely dissolved. Then weigh 1.2g of thioacetamide and add it to the solution in batches. Continue stirring for 15 minutes until the solution is transparent and uniform. Add 0.1M (about 16mL) hydrochloric acid dropwise until the pH stabilizes at 3.5±0.2. If the solution volume is reduced due to acid addition, make up to 500mL with the reserved 50mL deionized water and stir again for 5 minutes to ensure uniformity. Transfer the prepared solution to a 500mL polytetrafluoroethylene-lined reactor and seal it.

[0128] Step 1.2: Hydrothermal synthesis

[0129] Transfer the prepared pH 3.5 mixed solution to a 100mL polytetrafluoroethylene liner, ensuring the liquid level does not exceed 80mL. Place the liner in a stainless steel jacket and tighten the sealing cap to ensure no leaks. Place the reactor in an oven preheated to room temperature with the door closed. Set the oven to heat to 180°C at 3°C / min and maintain for 24 hours. After the reaction is complete, cool naturally to room temperature. Open the reactor and transfer the reaction solution to a 50mL centrifuge tube precooled to 4°C. Centrifuge at 8000 rpm for 15 minutes and discard the supernatant. Resuspend the precipitate in a mixture of ethanol and water (1:1 volume ratio) and ultrasonically disperse for 5 minutes. Repeat the centrifugation at 8000 rpm for 10 minutes and the washing step three times to precipitate the crude MoS2 product.

[0130] Step 1.3: Pulsed Laser Fragmentation

[0131] Equipment parameters: Nd:YAG solid-state laser (wavelength 1064 nm, near-infrared band); pulse energy 220 mJ / pulse (single pulse energy); frequency 12 Hz; spot diameter 2.5 mm; treatment time 30 minutes.

[0132] The TEM / SEM and AFM sample preparation methods are the same as in Example 1.

[0133] 2. Hydrophobic functionalization

[0134] 1.2 g of MoS2 nanosheet sample was added to 1 L of anhydrous ethanol and ultrasonicated for 30 minutes to form a uniform dispersion (concentration 1.2 mg / mL); 0.6 g of amino EO / PO surfactant C was weighed. 16 -EO5-PO 10 -C 16 -NH2, slowly added to the dispersion, stirred at 600 rpm at 60 ° C for 6 hours, so that the hydrophobic alkyl chain (C 16) adsorbed to the MoS2 surface through van der Waals forces, while the EO / PO chain segments extended outward and the terminal amino groups (-NH2) were exposed; centrifuged at 10,000 rpm for 10 minutes, and the supernatant (containing unreacted surfactant) was discarded; washed with 50 mL of anhydrous ethanol and centrifuged three times to obtain an NH2-EO / PO-MoS2 complex.

[0135] The method for verifying the hydrophobicity enhancement effect of EO / PO surfactant-modified MoS2 nanosheets (i.e., NH2-EO / PO-MoS2 complex) in a CO2 atmosphere is the same as that in Example 1.

[0136] 3. Microbial CO2-affinity functionalization

[0137] Step 3.1: The cyanobacteria culture and enzyme extraction process are the same as in Example 1.

[0138] Step 3.2: EDC / NHS-mediated enzyme immobilization

[0139] 1.0 g of NH2-EO / PO-MoS2 complex was mixed with 0.25 g of CA enzyme, and 12 mM EDC / NHS crosslinker (dissolved and diluted in pH 6 phosphate buffer) was added. The reaction was shaken at 37°C for 6 hours. The CA enzyme was immobilized on the surface of the nanosheet through carboxyl-amino covalent coupling. After centrifugation (10,000 rpm, 10 minutes) to remove the free enzyme, the precipitate was washed three times (pH 7.4 phosphate buffer) to obtain the CA-EO / PO-MoS2 complex.

[0140] 4. Anti-agglomeration and dispersion control

[0141] Prepare simulated formation water with a mineralization of 10,000 ppm, containing 8,500 mg / L Na + (8.5g / L NaCl), 1200mg / L Ca 2+ (2.94 g / L CaCl2·2H2O) and 300 mg / L Cl-, and the pH was adjusted to 7.0±0.2 with 0.1 M HCl / NaOH. 1.2 g of the CA-EO / PO-MoS2 complex was added to 1 L of the simulated formation water and pre-dispersed at 500 rpm for 10 minutes. Then, 6.0 mg of sophorolipid was added and stirred for 5 minutes for preliminary mixing. Ultrasonic treatment was performed continuously at 100 W for 10 minutes using a probe-type ultrasonic processor, maintaining the solution temperature below 25°C. The probe was immersed 1 cm below the liquid surface and moved at a constant speed to ensure uniform dispersion. After sonication, the dispersion was centrifuged at 5000 rpm at room temperature for 5 minutes. The trace precipitate at the bottom was discarded, and the supernatant was collected to obtain a stable dispersion containing CA-EO / PO-MoS2 nanosheets.

[0142] Effect verification

[0143] Effect example 1: Oil washing efficiency experiment

[0144] A muddy sandstone core (porosity 8.2%, permeability 0.12 mD) was vacuum-saturated with crude oil to an oil saturation of 68%. The core was placed in a high-temperature, high-pressure displacement device (60°C, 10 MPa) and 1 PV of displacement fluid was injected at a flow rate of 0.1 mL / min. The crude oil eluted at the outlet was collected, the volume was measured, and the mass was converted (the density of crude oil is 0.85 g / cm 3 ). Specific oil washing effect data are shown in Table 1;

[0145] Among them, the displacement fluid was prepared in three groups, namely:

[0146] Group 1: 0.1 wt% dispersion containing CA-EO / PO-MoS2 nanosheets prepared in step 4 of Example 1;

[0147] Group 2: 0.1 wt% unmodified MoS2 dispersion prepared in step 1 of Example 1;

[0148] The third group: 0.1 wt% SDS solution.

[0149] Table 1

[0150] Group Eluted oil weight (g) Saturated oil content (g) Oil washing efficiency (%) Group 1 8.2 10.0 82.0 Group 2 3.5 10.0 35.0 Group 3 5.8 10.0 58.0

[0151] As can be seen from Table 1, the oil washing efficiency of the experimental group reached 82%, far exceeding that of the control group, proving that the bifunctional nanosheet modification significantly improved the oil washing ability.

[0152] Effect Example 2: Permeability Control Experiment

[0153] The performance of the CA-EO / PO-MoS2 nanosheet dispersion prepared in step 4 of Example 1 in changing the oil / water phase permeability was evaluated using fractured shale cores.

[0154] (1) Core parameters:

[0155] Artificially fractured shale core (2.5 cm diameter, 10 cm length): Matrix properties: porosity 7.5%, permeability 0.02 mD; single artificially etched main fracture (directed parallel to the core axis), fracture width 30-80 μm; fracture filled with 120 mesh (particle size ≤ 125 μm) quartz sand to simulate the control of proppant on fracture conductivity after fracturing; gas permeability: 5.2 mD (simulating the combined seepage of natural fractures and matrix).

[0156] (2) Fluid:

[0157] Oil phase: simulated crude oil (viscosity 30 mPa·s, density 0.82 g / cm 3 ); Water phase: 10000ppm mineralized water (Na+ 8,500mg / L, Ca 2+ 1200 mg / L, Cl-300 mg / L, pH 7.0); nanofluid: 0.1 wt% CA-EO / PO-MoS2 dispersion (mineralization 10000 ppm).

[0158] The model was vacuumed and saturated with simulated formation water (12 hours, -0.1 MPa); the model was saturated with simulated oil until no more water was produced, thus constructing the original oil-water environment and measuring the effective permeability of the oil phase K. o,b ; Inject simulated formation water into the inlet section until oil stops flowing, and measure the effective permeability K of the water phase w,b ; Inject 1PV of 0.1wt% dispersion containing CA-EO / PO-MoS2 nanosheets at 0.02mL / min in the reverse direction and let it stand for 12 hours until adsorption equilibrium; inject simulated formation water again and measure the effective permeability K of the water phase after injection of the system w,a , calculate the residual resistance coefficient RFF of the water phase w ; Backward injection of simulated oil to calculate the effective permeability K of the oil phase o,a , and calculate the oil phase residual resistance coefficient RFF o Specific data are shown in Table 2.

[0159] The oil / water two-phase residual resistance coefficient is calculated as follows:

[0160] RRF o,w =K o,wb / K o,wa ;

[0161] RRF o,w is the residual resistance coefficient of oil / water phase, K o,wb and K o,wa The effective permeabilities of the oil / water phase before and after the injection of the dispersion containing CA-EO / PO-MoS2 nanosheets prepared in step 4 of Example 1 are shown respectively.

[0162] Table 2 Changes in oil / water permeability and residual resistance coefficient

[0163]

[0164] Experiments and Table 2 show that the model gas permeability is approximately 5.2 mD. After saturation with oil and water, the water phase permeability after injection of formation water is 3.8 mD. After reverse injection of 1 PV into the system and continued injection of formation water after adsorption equilibrium, the measured water phase permeability is 3.0 mD, the water phase residual resistance coefficient is 1.27, and the water phase permeability decreases by 21%. Before injection into the system, the measured oil phase effective permeability is 2.5 mD. After injection into the system, the measured oil phase effective permeability is 3.2 mD, the oil phase residual resistance coefficient is 0.78, and the oil phase permeability increases by 28%.

[0165] Effect Example 3: CO2 Storage Rate and Displacement Synergistic Experiment

[0166] A high-pressure visual microfluidic chip (simulating a fracture network, with a pore size of 10-50 μm) was used to test the CO2 adsorption and storage capacity of CA-EO / PO-MoS2 during CO2 flooding.

[0167] Control group 1: pure CO2 flooding (without nanofluid);

[0168] Control group 2: 0.1 wt% unmodified MoS2 dispersion prepared in step 1 of Example 1 + CO2 flooding;

[0169] Experimental group: 0.1 wt% dispersion containing CA-EO / PO-MoS2 nanosheets prepared in step 4 of Example 1 + CO2 flooding.

[0170] First, inject simulated crude oil to an oil saturation of 70% and record the initial oil volume (V o ); Secondly, inject CO2 (purity ≥99.9%, flow rate 0.05mL / min) until the CO2 concentration at the outlet is >95% (monitored by infrared CO2 sensor), and record the cumulative injected CO2 volume (V 注入CO2 ) and the volume of CO2 produced (V 出口CO2 ), collect the produced oil volume V o,out , calculate the oil displacement efficiency; finally, inject 0.1wt% of the dispersion of the corresponding group (mixed with CO2 at a volume ratio of 1:1); continue to inject CO2 (flow rate 0.05mL / min) until the outlet water content is greater than 98%, and record the cumulative injected CO2 volume (V 注入CO2 ) and the volume of CO2 produced (V 出口CO2 ), collect the produced oil volume V of the corresponding groups respectively o,out , calculate the oil displacement efficiency.

[0171] Calculate the storage rate:

[0172]

[0173] Calculate the oil displacement efficiency E:

[0174]

[0175] The experimental results are shown in Table 3.

[0176] Table 3

[0177] Group Oil displacement efficiency E(%) <![CDATA[CO2 sequestration rate (%)]]> <![CDATA[CO2 breakthrough time (PV)]]> Experimental group 75.2 85.3 1.5 Control group 1 48.6 58.9 0.8 Control group 2 55.1 67.4 1.0

[0178] As shown in Table 3, under conditions of a simulated fracture network (pore size 10-50 μm), the experimental group using a 0.1 wt% dispersion containing CA-EO / PO-MoS2 nanosheets mixed with CO2 to displace crude oil achieved an oil recovery efficiency of 75.2%, significantly higher than that of control group 1 (pure CO2 flooding, 48.6%) and control group 2 (0.1 wt% unmodified MoS2 dispersion + CO2 flooding, 55.1%). Furthermore, the experimental group also achieved the highest CO2 sequestration efficiency, reaching 85.3%, compared to 58.9% and 67.4% for control groups 1 and 2, respectively. Notably, the CO2 breakthrough time (i.e., the time it takes for CO2 to first reach the outlet) in the experimental group was 1.5 PV, significantly longer than that of control groups 1 (0.8 PV) and 2 (1.0 PV), indicating that the dispersion containing CA-EO / PO-MoS2 nanosheets effectively delayed CO2 breakthrough and prolonged the effective oil recovery time.

[0179] In summary, the CA-EO / PO-MoS2 nanosheet dispersion prepared in this invention, as a nanofluid, not only significantly improved crude oil displacement efficiency, but also significantly increased CO2 sequestration efficiency and prolonged CO2 breakthrough time, demonstrating its significant potential for enhancing oil recovery and reducing CO2 emissions. This discovery provides new ideas and methods for optimizing CO2 flooding technology.

[0180] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheets, characterized in that: The following steps are involved: MoS2 nanosheets were prepared by hydrothermal synthesis combined with pulsed laser fragmentation technology; The MoS2 nanosheets were modified with amino ethylene oxide / propylene oxide surfactants in sequence, and cyanobacterial carbonic anhydrase was covalently fixed on the surface of the nanosheets using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide / N-hydroxysuccinimide crosslinkers to prepare a CA-EO / PO-MoS2 composite with both hydrophobic and CO2-philic dual functions. The CA-EO / PO-MoS2 complex is dispersed in formation water, and sophorolipids are added thereto. After assisted ultrasound and centrifugation treatment, a highly stable dispersion containing CA-EO / PO-MoS2 nanosheets is obtained; wherein the CA-EO / PO-MoS2 nanosheets are the anti-agglomeration hydrophobic / co2philic molybdenum disulfide nanosheets.

2. The method for preparing an anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheet according to claim 1, characterized in that: The preparation method specifically comprises the following steps: (1) adding thioacetamide to an aqueous solution of ammonium heptamolybdate, adjusting the pH, and stirring uniformly to prepare a precursor solution; then subjecting the precursor solution to a hydrothermal synthesis reaction, a pulsed laser fragmentation treatment, and drying to obtain MoS2 nanosheets; (2) preparing the MoS2 nanosheets into a MoS2 dispersion, adding an amino ethylene oxide / propylene oxide surfactant thereto, stirring evenly, and then centrifuging and washing to obtain an NH2-EO / PO-MoS2 complex; (3) subjecting the NH2-EO / PO-MoS2 complex to an oscillating reaction with cyanobacterial carbonic anhydrase in the presence of a 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide crosslinker to obtain a CA-EO / PO-MoS2 complex; (4) adding the CA-EO / PO-MoS2 complex and sophorolipids to formation water, stirring evenly, and then ultrasonically treating and centrifuging to obtain a dispersion containing CA-EO / PO-MoS2 nanosheets.

3. The method for preparing an anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheet according to claim 2, characterized in that: In step (1), the mass ratio of ammonium heptamolybdate to the thioacetamide in the ammonium heptamolybdate aqueous solution is (4.0-4.8): (1.0-1.2).

4. The method for preparing an anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheet according to claim 2, characterized in that: In step (1), the conditions during the hydrothermal synthesis reaction are: heating to 180°C at a heating rate of 1-3°C / min, and then keeping at this temperature for 24 hours.

5. The method for preparing an anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheet according to claim 2, characterized in that: In step (1), the conditions of the pulse laser fragmentation process are: pulse energy of 180-220 mJ / pulse; frequency of 8-12 Hz; spot diameter of 1.5-2.5 mm; and treatment time of 30 minutes.

6. The method for preparing the anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheets according to claim 2, characterized in that: In step (2), the amount ratio of the MoS2 dispersion and the amino ethylene oxide / propylene oxide surfactant is: 1.0L: (0.4-0.6)g; The concentration of the MoS2 dispersion is 0.8-1.2 mg / mL.

7. The method for preparing an anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheet according to claim 2, characterized in that: In step (3), the extraction process of the cyanobacterial carbonic anhydrase is as follows: The cyanobacteria were cultured in BG-11 medium until the middle of the logarithmic growth phase, the cells were collected by centrifugation, and then subjected to ultrasonic disruption and ammonium sulfate graded precipitation to extract the crude enzyme solution.

8. The method for preparing an anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheet according to claim 2, characterized in that: In step (3), the amount ratio of the NH2-EO / PO-MoS2 complex, cyanobacterial carbonic anhydrase and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide crosslinker is 1.0 g: (0.15-0.25) g: (8-12) mM; In step (4), the ratio of the formation water, CA-EO / PO-MoS2 complex and sophorolipid is: 1L: (0.8-1.2) g: (4.0-6.0) mg.

9. An anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheet, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the anti-agglomeration hydrophobic / CO2-philic molybdenum disulfide nanosheets according to claim 9 in the field of shale oil and gas extraction.

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