An environment-friendly grounding resistance reducer suitable for sandy and desert geological soil, its preparation method and application

Abstract

The present invention belongs to the technical field of resistance reducing agents, aiming to solve the problems that existing resistance reducing agents are not environmentally friendly and easily affect the ecological environment, and the poor resistance reducing performance leads to frequent construction that will damage the surface vegetation and soil structure. For this purpose, the present invention provides an environmentally friendly resistance reducing agent suitable for sandy, gobi and desert geological soils, its preparation method and application. The environmentally friendly resistance reducing agent includes 15-20 parts of nano graphene, 8-12 parts of nano barium titanate, 5-8 parts of metal-organic framework materials, 10-15 parts of polyvinyl butyral-sodium alginate composite hydrogel, 5-8 parts of polyaspartic acid, 8-12 parts of phosphogypsum, 4-6 parts of composite microbial flora, 8-12 parts of binder, 3-5 parts of stabilizer, 2-3 parts of surfactant, 2-3 parts of activation assistant and 20-30 parts of water. The resistance reducing agent of the present invention does not contain heavy metal ions and toxic and harmful substances, is environmentally friendly and does not affect the ecological environment, and has good water retention performance, and can decompose organic substances in the soil, release conductive ions, improve and maintain the conductive performance of the resistance reducing agent.

Description

Technical Field

[0001] The present invention relates to the technical field of resistance reducing agents, and particularly relates to an environment-friendly resistance reducing agent suitable for sandy, arid and desert geological soils, its preparation method and application. Background Art

[0002] With the acceleration of the global industrialization and urbanization processes, the infrastructure construction in many fields such as power transmission, communication base stations, petrochemical industry, etc. has been continuously expanding towards the vast sandy, arid and desert areas. In these areas, the soil resistivity is usually relatively high, which poses great challenges to the design and implementation of grounding systems. Existing resistance reducing methods often have many drawbacks and are difficult to meet the requirements of modern engineering for efficient, environment-friendly and sustainable resistance reduction.

[0003] Under the geological conditions of sandy, arid and desert areas, the high resistivity of the soil mainly stems from its special physical and chemical properties. Such soils have coarse particles, high porosity, low water content and lack conductive ions, making it difficult for current to conduct in them. In the early stage, in order to reduce the soil resistance, the method of adding a large amount of chemical resistance reducing agents was often used. However, most of these existing chemical resistance reducing agents contain heavy metal ions (such as mercury, cadmium, lead, etc.) and toxic and harmful substances (such as cyanides, halides, etc.). They will not only cause serious pollution to the soil environment, damage the ecological balance of the soil, affect the local vegetation growth and microbial community, but also with the action of rainwater scouring, etc., these harmful substances may seep into the underground water body, pollute the water resources, and further threaten the surrounding ecological system and human health.

[0004] In addition, the resistance reducing effects of existing resistance reducing measures are often not durable and stable enough. Due to the harsh climate conditions in sandy, arid and desert areas, such as high temperature, drought, strong wind, etc., the resistance reducing agent is easy to volatilize, lose or be adsorbed and fixed by soil particles, resulting in a rapid decline in its conductive performance over time, and frequent maintenance and repair are required, increasing the project cost and operation risk. Moreover, some existing construction methods are difficult to implement in sandy, arid and desert areas. For example, large-area land turning and deep excavation operations not only consume a large amount of manpower, material resources and financial resources, but also cause irreversible damage to the surface vegetation and soil structure, exacerbate environmental problems such as land desertification and soil erosion, and further damage the local fragile ecological environment.

[0005] In view of this, there is a need in the art for an environment-friendly resistance reducing agent suitable for sandy, arid and desert geological soils, its preparation method and application to solve the above problems. Summary of the Invention

[0006] In order to solve the above technical problems, that is, to solve the problems that the existing resistance reducing agents are not environmentally friendly and easily affect the ecological environment, and the poor resistance reducing performance leads to frequent construction that will damage the surface vegetation and soil structure.

[0007] In a first aspect, the present invention provides an environmentally friendly resistance reducing agent suitable for sandy and barren geological soils, and the environmentally friendly resistance reducing agent comprises 15-20 parts of nano graphene, 8-12 parts of nano barium titanate, 5-8 parts of metal-organic framework material, 10-15 parts of polyvinyl butyral-sodium alginate composite hydrogel, 5-8 parts of polyaspartic acid, 8-12 parts of phosphogypsum, 4-6 parts of composite microbial flora, 8-12 parts of binder, 3-5 parts of stabilizer, 2-3 parts of surfactant, 2-3 parts of activation assistant and 20-30 parts of water.

[0008] In some preferred embodiments, the binder is an epoxy resin emulsion and the stabilizer is sodium carboxymethyl cellulose.

[0009] In some preferred embodiments, the surfactant is sodium dodecyl benzene sulfonate and the activation assistant is disodium ethylenediaminetetraacetate.

[0010] The environmentally friendly resistance reducing agent suitable for sandy and barren geological soils of the present invention has the following beneficial effects:

[0011] In the environmentally friendly resistance reducer of the present invention, through the synergistic effect of various highly efficient conductive components such as nano-graphene, nano-barium titanate, and metal-organic framework materials, these materials have unique microstructures and electrical properties, and can build an efficient conductive network in the sandy desert soil, effectively reducing the resistivity of the soil and significantly improving the current conduction ability; the resistance reducer completely abandons the common heavy metal ions (such as mercury, cadmium, lead, etc.) and toxic and harmful substances (such as cyanides, halides, etc.) in traditional resistance reducers, avoiding the pollution of the fragile soil ecological environment in the sandy desert area from the source. This not only helps to protect the local vegetation growth and the stability of the microbial community, maintain the ecological balance of the soil, but also prevents harmful substances from infiltrating into the groundwater body, ensuring the safety of the surrounding water resources; components such as polyvinyl butyral-sodium alginate composite hydrogel and polyaspartic acid have good water retention performance, can absorb and store a certain amount of water, increase the water content of the sandy desert soil, improve the electrical conductivity of the soil, and at the same time reduce the evaporation and loss of water, creating a relatively humid environment for plant growth and microbial activities. The addition of phosphogypsum can adjust the soil pH value, supplement elements such as calcium and sulfur in the soil, improve the soil compaction condition, enhance soil fertility, promote the optimization of the soil structure, and is conducive to the restoration and growth of vegetation, further improving the comprehensive improvement effect of the resistance reducer on the sandy desert soil; the presence of the composite microbial flora can continuously metabolize in the soil, decompose the organic matter in the soil, release conductive ions, maintain the electrical conductivity of the resistance reducer, and at the same time its metabolites can improve the soil structure, enhance the binding force between the resistance reducer and soil particles, reduce problems such as volatilization, loss, and adsorption and fixation of the resistance reducer caused by climate factors (such as high temperature, drought, strong wind, etc.), making the resistance reduction effect more durable and stable, reducing the maintenance cost and operation risk of the project, and improving the reliability and stability of the infrastructure operation in the sandy desert area.

[0012] In a second aspect, the present invention provides a preparation method of the above-mentioned environmentally friendly resistance reducer suitable for sandy desert geological soil, and the preparation method includes:

[0013] S1: Pretreat graphene nanosheets, barium titanate nanoparticles, metal-organic framework materials, and polyvinyl butyral-sodium alginate composite hydrogel;

[0014] S2: Sequentially add the pretreated graphene nanosheets, barium titanate nanoparticles, metal-organic framework materials, polyvinyl butyral-sodium alginate composite hydrogel, polyaspartic acid, epoxy resin emulsion, sodium carboxymethylcellulose, phosphogypsum, composite microbial flora, sodium dodecylbenzenesulfonate, and disodium ethylenediaminetetraacetate into the ball mill pot of the ball mill, add water and grinding balls, where the ball-to-material ratio is 3:1, the rotation speed of the ball mill is 300 - 500 rpm, and the ball milling time is 4 - 6 hours;

[0015] S3: Transfer the mixture after ball milling to a reaction kettle and continue stirring and reacting at 50 - 60 °C for 2 - 3 hours;

[0016] S4: Cool the reaction product of step S3 to room temperature, remove excess moisture and bubbles by vacuum filtration to obtain the environmentally friendly drag reducer paste.

[0017] In some preferred embodiments, in step S1, the pretreatment of graphene nanosheets includes:

[0018] Add graphene nanosheets to a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, stir and react at 60 - 80 °C for 2 - 3 hours for oxidation treatment;

[0019] Wash the oxidized graphene nanosheets repeatedly with deionized water until neutral, then add them to a hydrazine hydrate solution and carry out a reduction reaction at 80 - 100 °C for 1 - 2 hours.

[0020] In some preferred embodiments, in step S1, the pretreatment of barium titanate nanoparticles includes:

[0021] Prepare tetrabutyl titanate ethanol solution and barium acetate ethanol solution respectively;

[0022] Under vigorous stirring at 800 - 1000 rpm, slowly drop the tetrabutyl titanate ethanol solution into the barium acetate ethanol solution, and at the same time add glacial acetic acid as a catalyst to control the pH value of the solution between 3 - 4. After dropping, continue stirring for 1 - 2 hours to form a uniform sol;

[0023] Transfer the sol to a high-pressure reaction kettle and carry out a hydrothermal reaction at 150 - 200 °C for 12 - 24 hours;

[0024] After the reaction ends, cool naturally to room temperature, and obtain barium titanate nanoparticles through centrifugal separation, washing, and drying.

[0025] In some preferred embodiments, in step S1, the pretreatment of metal-organic framework materials includes:

[0026] Using copper nitrate and terephthalic acid as raw materials, dissolve copper nitrate in a mixed solution of N,N-dimethylformamide and ethanol with a volume ratio of 1:1, and add acetic acid to adjust the acidity of the solution;

[0027] Add terephthalic acid to the above solution and ultrasonically disperse for 30 - 60 minutes;

[0028] Transfer the solution to a reaction kettle lined with polytetrafluoroethylene and carry out a solvothermal reaction at 120 - 150 °C for 24 - 48 hours;

[0029] After the reaction is completed, it is cooled to room temperature, washed repeatedly by centrifugal separation, N,N-dimethylformamide and ethanol, and finally dried in a vacuum drying oven at 80-100 °C for 12-24 hours to obtain blue metal-organic framework crystals.

[0030] In some preferred embodiments, in step S1, the pretreatment of the polyvinyl butyral-sodium alginate composite hydrogel includes:

[0031] Dissolve polyvinyl butyral in water, heat to 80-90 °C, and stir until completely dissolved to obtain a polyvinyl butyral solution;

[0032] Slowly add sodium alginate to the polyvinyl butyral solution, continue stirring for 30-60 minutes, then add a crosslinking agent, control the dosage of the crosslinking agent to be 1-2% of the mass of sodium alginate, and react at 50-60 °C for 1-2 hours to form a polyvinyl butyral-sodium alginate composite hydrogel;

[0033] Wash the prepared polyvinyl butyral-sodium alginate composite hydrogel repeatedly with deionized water, then dry it at 40-50 °C, and then crush it.

[0034] The preparation method of the environment-friendly resistance reducer suitable for sandy and barren geological soils of the present invention has the following beneficial effects:

[0035] In the preparation method of the environment-friendly resistance reducer of the present invention, specific pretreatment methods are adopted according to the characteristics of different raw materials. For example, graphene nanosheets are subjected to redox treatment, and functional groups such as carboxyl groups and hydroxyl groups are introduced onto their surfaces and then reduced, which improves the dispersibility and conductivity of graphene in the resistance reducer system; barium titanate nanoparticles are obtained by precisely controlling the sol-gel method and the hydrothermal reaction process to obtain products with uniform particle size and good activity; metal-organic framework materials are subjected to solvothermal synthesis and post-treatment to ensure that they have a high specific surface area and a suitable pore structure; polyvinyl butyral-sodium alginate composite hydrogels are optimized in cross-linking reaction conditions to make them have good water retention and bonding properties. These pretreatment steps lay a solid foundation for the subsequent preparation of high-performance resistance reducers, ensuring that each raw material can fully play its function and improving the overall performance of the resistance reducer; a ball mill is used for mixing and grinding, and the rotation speed, ball-to-material ratio, and ball milling time of the ball mill are precisely controlled, so that various raw materials with different properties are highly uniformly mixed and undergo physical and chemical reactions at the microscopic level under the action of mechanical force, promoting the interaction between components and the exertion of synergistic effects. The stirring reaction step in the reaction kettle after ball milling further optimizes the overall performance of the resistance reducer, curing and cross-linking the epoxy resin emulsion, stabilizing the structure of the resistance reducer, ensuring the quality stability and performance consistency of the resistance reducer, avoiding problems such as fluctuations in the resistance reduction effect and local performance differences caused by uneven mixing, and improving the reliability and practicability of the resistance reducer; solvents, reagents, etc. used in the entire preparation process are reasonably selected and strictly controlled, avoiding the use of toxic, harmful, and highly volatile chemical substances, reducing environmental pollution and harm to the health of operators. At the same time, through precise control of temperature, time, and raw material ratio, the controllability and repeatability of the preparation process are improved, which is conducive to achieving scale production and ensuring the stability and consistency of the performance of resistance reducer products in different batches, providing technical support for the industrial production and wide application of resistance reducers.

[0036] In a third aspect, the present invention provides an application of the environment-friendly resistance reducer suitable for sandy, arid, and barren geological soils as described above, and the application includes:

[0037] Determine the construction area of the resistance reducer for the soil, drill holes at intervals of 0.5 - 1 meter in the construction area of the resistance reducer to form a grid-like hole network, wherein the drilling depth is 1.0 - 1.5 meters, and the diameter of the holes is 5 - 10 centimeters;

[0038] Level, clean, and compact the soil surface in the construction area of the resistance reducer, and the compactness is 70 - 80%;

[0039] Dilute a part of the environment-friendly resistance reducer with water according to a volume ratio of 1:1.5 - 1:2.5, and do not dilute the other part;

[0040] Inject the undiluted environment-friendly resistance reducer into the pre-drilled holes through a pressure pump and a pipeline conveying system at a pressure of 0.5 - 1.0 MPa and an injection rate of 1 - 2 L / min;

[0041] Spray the diluted environment-friendly resistance reducer layer by layer in a crisscross pattern on the construction area of the resistance reducer, where the spraying amount is 3 - 5 liters per square meter;

[0042] Carry out rotary tillage and stirring on the construction area of the resistance reducer, and then, in the soil layer after rotary tillage and stirring, inject the undiluted environment-friendly resistance reducer again according to the method of hole injection;

[0043] After the injection and spraying of the environment-friendly resistance reducer are completed, deeply plow the soil in the entire construction area of the resistance reducer;

[0044] After the deep plowing is completed, compact the soil by the method of layered ramming, and the compaction degree is 90 - 95%;

[0045] In some preferred embodiments, the operation of rotary tillage and stirring is carried out by multiple rotary tillers. The rotary tillage depth of the rotary tiller is 0.3 - 0.5 meters, the traveling speed of the rotary tiller is 0.5 - 1.0 m / s, and the rotational speed of the rotary tillage blade of the rotary tiller is 200 - 300 rpm;

[0046] The operation of deep plowing is carried out by a deep plow. The plowing depth of the deep plow is 1.0 - 1.5 meters, and the traveling speed of the deep plow is 0.5 - 1.0 m / s.

[0047] The application of the environment-friendly resistance reducer suitable for sandy and desert-like geological soil of the present invention has the following beneficial effects:

[0048] In the application of the environment-friendly resistance-reducing agent of the present invention, by drilling holes in the construction area of the resistance-reducing agent at specific intervals and depths to form a grid-like hole network, the contact area and penetration channels between the resistance-reducing agent and the soil are increased, enabling the resistance-reducing agent to penetrate deep into the soil layer, effectively solving the problem that the resistance-reducing agent is not easily penetrated due to the coarse soil particles and high porosity in sandy, rocky and desert areas, and improving the uniformity and stability of the resistance-reducing effect; a construction method is adopted in which a part of the environment-friendly resistance-reducing agent is diluted and sprayed in layers, and then combined with rotary tillage and stirring, so that the resistance-reducing agent can form a uniform conductive layer on the soil surface and be fully mixed with the soil particles, ensuring that the resistance-reducing agent can cover the surface of each soil particle, improving the utilization efficiency and resistance-reducing effect of the resistance-reducing agent. Then, the undiluted resistance-reducing agent is injected into the holes again to further strengthen the conductive network in the deep soil layer, forming a multi-layer resistance-reducing structure, effectively coping with the complex soil conditions in sandy, rocky and desert areas, and improving the stability and reliability of the grounding system; after the injection and spraying of the resistance-reducing agent are completed, a deep plow is used for deep tillage to fully and evenly mix the resistance-reducing agent with the soil, ensuring the uniform distribution of the resistance-reducing agent in the soil and forming a continuous conductive path. Subsequently, a method of layered compaction is used to compact the soil, so that the resistance-reducing agent is tightly combined with the soil, not only improving the density and mechanical properties of the soil, preventing the influence of soil settlement and deformation on the resistance-reducing effect, but also enhancing the stability of the resistance-reducing structure, reducing problems such as volatilization and loss of the resistance-reducing agent under harsh climate conditions, ensuring the long-term effectiveness and stability of the resistance-reducing project, and providing a reliable grounding guarantee for the infrastructure construction in sandy, rocky and desert areas; the entire application process pays attention to the environmental protection of the construction area. Before construction, the soil surface is leveled and cleaned to avoid excessive damage to the surface vegetation. After construction, through reasonable compaction and maintenance measures, it is beneficial to the restoration and growth of vegetation, reducing environmental problems such as soil erosion and land desertification. At the same time, due to the environmental protection characteristics of the resistance-reducing agent itself and the scientific nature of the construction method, the resistance-reducing project minimizes the impact on the ecological environment of sandy, rocky and desert areas while achieving efficient resistance reduction, conforming to the principle of sustainable development, and providing a balanced solution for the long-term development and ecological protection of this area. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings. The drawings are schematic and should not be construed as imposing any limitation on the present invention. In the drawings:

[0050] Figure 1 It is a flow chart of the preparation method of the environment-friendly resistance-reducing agent suitable for sandy, rocky and desert geological soil of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0052] Based on the problems pointed out in the background technology that the existing resistance reducers are not environmentally friendly and easily affect the ecological environment, and the poor resistance reduction performance leads to frequent construction that will damage the surface vegetation and soil structure, the present invention provides an environmentally friendly resistance reducer suitable for sandy, gravelly, and barren geological soils, its preparation method, and application. The aim is to use environmentally friendly components for the resistance reducer, completely abandoning the common heavy metal ions (such as mercury, cadmium, lead, etc.) and toxic and harmful substances (such as cyanides, halides, etc.) in traditional resistance reducers, avoiding the pollution of the fragile soil ecological environment in sandy, gravelly, and barren areas from the source. Moreover, the resistance reducer has good water retention performance, can absorb and store a certain amount of water, increase the water content of sandy, gravelly, and barren soils, improve the electrical conductivity of the soil, and at the same time reduce the evaporation and loss of water, creating a relatively humid environment for plant growth and microbial activities. In addition, the resistance reducer also decomposes the organic matter in the soil, releases conductive ions, maintains the electrical conductivity of the resistance reducer, and at the same time its metabolites can also improve the soil structure, enhance the binding force between the resistance reducer and soil particles, reduce problems such as volatilization, loss, and adsorption and fixation of the resistance reducer caused by climatic factors (such as high temperature, drought, strong wind, etc.), making the resistance reduction effect more durable and stable, reducing the maintenance cost and operation risk of the project, and improving the reliability and stability of the infrastructure operation in sandy, gravelly, and barren areas.

[0053] The environmentally friendly resistance reducer of the present invention comprises 15 - 20 parts of nano graphene, 8 - 12 parts of nano barium titanate, 5 - 8 parts of metal-organic framework material, 10 - 15 parts of polyvinyl butyral-sodium alginate composite hydrogel, 5 - 8 parts of polyaspartic acid, 8 - 12 parts of phosphogypsum, 4 - 6 parts of composite microbial flora, 8 - 12 parts of binder, 3 - 5 parts of stabilizer, 2 - 3 parts of surfactant, 2 - 3 parts of activation assistant, and 20 - 30 parts of water.

[0054] Preferably, the binder is epoxy resin emulsion, the stabilizer is sodium carboxymethyl cellulose, the surfactant is sodium dodecyl benzene sulfonate, and the activation assistant is disodium ethylenediaminetetraacetate.

[0055] It should be noted that in the above, the raw material of nano-graphene is graphene nanosheets, which have excellent electrical properties. Their two-dimensional sheet structure can provide an efficient electron conduction channel, significantly enhancing the conductivity of the resistance reducer; nano-barium titanate can improve the dielectric properties of the resistance reducer, promote the polarization and movement of charges, and the small size effect of the nano-particles enables it to better fill the gaps between other materials, optimizing the conductive path; the unique porous structure of metal-organic framework materials (MOFs) can not only adsorb and store a certain amount of conductive ions, but also serve as a conductive carrier, further enhancing the overall conductive performance of the resistance reducer; the water retention and ion slow-release system is realized through polyvinyl butyral (PVB)-sodium alginate composite hydrogel and polyaspartic acid (PASP). PVB provides good film-forming properties and mechanical strength. Sodium alginate has abundant carboxyl groups, can absorb a large amount of water and chelate with metal ions. Polyaspartic acid (PASP) can chelate metal ions in the soil, prevent their precipitation and loss. At the same time, its own ionization characteristics also help to improve the conductivity of the soil, and can promote the absorption of nutrients by plant roots, which is beneficial to improving the soil ecological environment in sandy, rocky and desert areas; sodium carboxymethyl cellulose (CMC) is used as a thickener and stabilizer to increase the viscosity and stability of the resistance reducer, prevent sedimentation and stratification of each component during storage and use, ensure the uniformity and consistency of the resistance reducer, and CMC is a natural cellulose derivative with good biocompatibility and biodegradability; phosphogypsum contains abundant elements such as calcium and sulfur, can adjust the pH value of the soil, improve the soil compaction condition, and at the same time provide a certain nutrient source for microorganisms, promote the growth and reproduction of microorganisms, which is beneficial to the optimization of soil structure and the improvement of conductive performance; the composite microbial flora is composed of a variety of functional microorganisms, such as nitrogen-fixing bacteria, phosphate-solubilizing bacteria, photosynthetic bacteria, etc. These microorganisms can carry out a series of metabolic activities in the soil, decompose the organic matter in the soil, release more conductive ions, enhance the soil fertility and air permeability, and the microbial flora can be subjected to special embedding treatment to make it have better activity and stability in the resistance reducer, ensuring that it can continuously play a role after construction. For example, in the embedding process, a sodium alginate-calcium chloride system is used. The microbial flora is evenly dispersed in the sodium alginate solution, and then dropped into the calcium chloride solution drop by drop to form gel microspheres to embed and protect the microorganisms, improving their survival time and activity in the resistance reducer; sodium dodecyl benzene sulfonate, as an anionic surfactant, can reduce the surface tension between solid particles, improve its dispersibility in the resistance reducer system, prevent particle agglomeration, ensure that each component plays its full role, and at the same time has a certain cleaning and dispersing effect on some impurities such as oil stains in the soil, which is beneficial to the close contact between the resistance reducer and the soil;Disodium ethylenediaminetetraacetate (EDTA-2Na) can form stable complexes with metal ions, activate and slowly release metal ions in the resistance reducer, improve its conductivity efficiency, and also help prevent metal ions from precipitating and passivating in the soil, maintaining the long-term effectiveness of the resistance reducer.

[0056] As Figure 1 shown, the preparation method of the environment-friendly resistance reducer suitable for sandy and desertified geological soil of the present invention includes:

[0057] S1: Pretreat graphene nanosheets, barium titanate nanoparticles, metal-organic framework materials, and polyvinyl butyral-sodium alginate composite hydrogels.

[0058] Preferably, in step S1, the pretreatment of graphene nanosheets includes:

[0059] Add graphene nanosheets to a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, stir and react at 60-80 °C for 2-3 hours for oxidation treatment; the oxidation process can introduce oxygen-containing functional groups such as carboxyl (-COOH) and hydroxyl (-OH). The introduction of these functional groups can improve the hydrophilicity and surface activity of graphene nanosheets, making them more easily dispersed in the subsequent resistance reducer system and capable of undergoing chemical reactions with other components to enhance the overall performance of the resistance reducer. To ensure the appropriate degree of oxidation reaction and introduce an appropriate amount of oxygen-containing functional groups such as carboxyl (-COOH) and hydroxyl (-OH), various methods can be used for monitoring and control during the reaction. For example, samples can be taken at regular intervals, and the samples can be analyzed using infrared spectroscopy (FT-IR) technology. The progress of the oxidation reaction can be judged by observing the appearance and intensity changes of the absorption peaks of specific functional groups. Generally, as the oxidation reaction proceeds, a C=O stretching vibration absorption peak of carboxyl will appear near 1700-1750 cm -1 -1, and a hydroxyl absorption peak will appear near 3200-3600 cm -1Within this range, an absorption peak of the O-H stretching vibration of the hydroxyl group will appear, and the intensity of the peak will gradually increase with the prolongation of the reaction time. When the absorption peak intensity of these functional groups reaches the expected range, the reaction can be stopped to avoid the destruction of the graphene nanosheet structure and the deterioration of performance caused by over-oxidation; the oxidized graphene nanosheets are repeatedly washed with deionized water (the amount of deionized water is generally 10-15 times the volume of the reaction solution) until neutral, and then added to a hydrazine hydrate solution (according to the mass of the graphene oxide nanosheets and the required reduction degree, generally the mass ratio of hydrazine hydrate to graphene oxide nanosheets is 1:2-1:3). The reduction reaction is carried out at 80-100 °C for 1-2 hours. During the reaction, the reaction system is continuously stirred, and the stirring speed is controlled at 400-600 rpm to ensure that hydrazine hydrate and graphene oxide nanosheets are fully contacted and the reduction reaction occurs; after the reduction reaction is completed, the reaction product is cooled to room temperature, and the precipitate is collected again by centrifugation and washed alternately with a large amount of deionized water and absolute ethanol 3-5 times to remove unreacted hydrazine hydrate and other impurities. Finally, the washed graphene nanosheets are transferred to a vacuum drying oven and dried at 50-60 °C for 12-24 hours to obtain dried pretreated graphene nanosheets. During the vacuum drying process, the vacuum degree (generally 0.05-0.1 MPa) and the drying time should be controlled to ensure that the graphene nanosheets are completely dried and do not agglomerate, and the obtained product should have good dispersibility and high conductivity.

[0060] Preferably, in step S1, the pretreatment of the barium titanate nanoparticles includes:

[0061] Prepare tetrabutyl titanate ethanol solution and barium acetate ethanol solution separately; under vigorous stirring at 800 - 1000 rpm, slowly drop the tetrabutyl titanate ethanol solution into the barium acetate ethanol solution, controlling the dropping speed at 1 - 2 drops per second. Meanwhile, add glacial acetic acid as a catalyst to control the pH value of the solution between 3 - 4. After the dropping is completed, continue stirring for 1 - 2 hours to form a homogeneous sol; transfer the prepared sol to a high-pressure reaction kettle with a PTFE liner, and control the filling degree at 60 - 80% to ensure there is enough space for the reaction during the reaction process and avoid potential safety hazards caused by excessive pressure due to too high filling degree. After sealing the reaction kettle, place it in an oven preheated to 150 - 200 °C for hydrothermal reaction for 12 - 24 hours. During the hydrothermal reaction, the temperature and pressure inside the reaction kettle will gradually increase, promoting the nucleation and growth of barium titanate nanoparticles; after the hydrothermal reaction is completed, take out the reaction kettle from the oven and let it cool naturally to room temperature. After the reaction kettle is completely cooled, open the reaction kettle, pour the reaction product into a centrifuge tube, add an appropriate amount of absolute ethanol and deionized water (volume ratio 1:1), and use a high-speed centrifuge to centrifuge at a speed of 8000 - 10000 rpm for 10 - 15 minutes. Remove the supernatant and collect the precipitate. Repeat the above washing steps 3 - 5 times to thoroughly remove the impurity ions adsorbed on the surface of the reaction product and the unreacted raw materials. Then, transfer the washed precipitate to a vacuum drying oven and dry it at 60 - 80 °C for 12 - 24 hours to obtain dry barium titanate nanoparticle powder; use an X-ray diffractometer (XRD) to analyze the crystal form of the prepared barium titanate nanoparticles. Uniformly smear a small amount of the dried sample on the sample stage, use a CuKα radiation source (λ = 0.15406 nm), scan within the 2θ range of 20° - 80°, and the scanning speed is 5° - 10° / min. By comparing with the standard barium titanate XRD pattern, determine the crystal phase structure of the product, and calculate the grain size using the Scherrer formula based on the full width at half maximum of the diffraction peak to ensure that its particle size is within the range of 20 - 50 nm and has good crystallinity.

[0062] Preferably, in step S1, the pretreatment of the metal-organic framework material includes:

[0063] Using copper nitrate and terephthalic acid as raw materials, dissolve copper nitrate in a mixed solution of N,N-dimethylformamide (DMF) and ethanol with a volume ratio of 1:1, and add acetic acid to adjust the acidity of the solution, such as pH = 3.5 - 4.5; add terephthalic acid to the above solution, ultrasonic disperse for 30 - 60 minutes, with a frequency of kHz; transfer the solution to a reaction kettle lined with polytetrafluoroethylene, and control the filling degree at 60 - 70% to reserve enough space for solvent volatilization and crystal growth during the reaction, while ensuring the safe use of the reaction kettle. After sealing the reaction kettle, place it in an oven preheated to 120 - 150 °C for solvothermal reaction for 24 - 48 hours. During the reaction, the temperature and pressure in the reaction kettle will gradually increase. The solvents DMF and ethanol act as reaction media under high temperature and high pressure to promote the coordination reaction between copper nitrate and terephthalic acid, form the crystal nuclei of MOFs and gradually grow into crystals; after the solvothermal reaction is completed, take out the reaction kettle from the oven and naturally cool it to room temperature. After the reaction kettle is completely cooled, carefully open the reaction kettle, pour the reaction product into a centrifuge tube, first add an appropriate amount of DMF, and use a high-speed centrifuge to centrifuge and separate at a speed of 8000 - 10000 rpm for 10 - 15 minutes, discard the supernatant to remove the unreacted raw materials and impurities adsorbed on the surface of the reaction product. Then, repeat the above centrifugal washing step with ethanol 3 - 5 times to further remove the residual DMF and other impurities and ensure the purity of the MOFs crystals; transfer the washed MOFs crystals to a vacuum drying oven and dry them at 80 - 100 °C for 12 - 24 hours. During the drying process, control the vacuum degree at 0.08 - 0.1 MPa to ensure that the MOFs crystals are completely dried and do not agglomerate. The dried MOFs crystals are blue and have a regular crystal morphology; use a specific surface area and pore size analyzer (BET) to measure the specific surface area and pore size distribution of the MOFs crystals. Pretreat a small amount of dried MOFs samples under vacuum conditions to remove the gas and impurities adsorbed on the surface of the samples, and then conduct a nitrogen adsorption - desorption experiment at liquid nitrogen temperature. Calculate the specific surface area and pore size distribution of the samples according to the BET theory and the Barrett-Joyner-Halenda (BJH) method to ensure that its specific surface area can reach 1000 - 2000 m 2 / g, and the pore size distribution is in the range of 1 - 3 nm, meeting the expected performance indicators to ensure that MOFs can fully play the advantages of its porous structure in the drag reducer system, such as adsorbing and storing conductive ions, optimizing the conductive path, etc.

[0064] Preferably, in step S1, the pretreatment of the polyvinyl butyral-sodium alginate composite hydrogel includes:

[0065] Dissolve polyvinyl butyral (PVB) in water, heat to 80-90°C, and stir until completely dissolved to obtain a polyvinyl butyral solution; slowly add sodium alginate to the polyvinyl butyral solution, continue stirring for 30-60 minutes, then add a crosslinking agent (such as glutaraldehyde), control the amount of the crosslinking agent to be 1-2% of the mass of the sodium alginate, and react at 50-60°C for 1-2 hours to allow a crosslinking reaction to occur between the PVB and the sodium alginate to form a composite hydrogel with a three-dimensional network structure; after the crosslinking reaction is completed, remove the prepared hydrogel and soak and wash it in a large amount of deionized water, wherein the amount of deionized water is generally 10% of the volume of the hydrogel. -15 times, the soaking time is 2-3 hours, during which the deionized water is replaced every 30-40 minutes. The unreacted cross-linking agent and other impurities in the hydrogel are removed by multiple soaking and water changes; the washed hydrogel is taken out from the deionized water, the surface moisture is absorbed with filter paper, and then transferred to a vacuum drying oven and dried to constant weight at 40-50°C. The vacuum degree is controlled at 0.05-0.08MPa during the drying process to ensure that the moisture in the hydrogel can be fully volatilized, while avoiding damage to the hydrogel structure or degradation of performance due to excessive temperature. The dried hydrogel is in block form and is crushed into particles with a particle size of 1-3mm using a grinder.

[0066] In the above, in addition to pre-treating graphene nanosheets, barium titanate nanoparticles, metal organic framework materials and polyvinyl butyral-sodium alginate composite hydrogel, other components can also be pre-treated, such as:

[0067] Polyaspartic acid (PASP): Dry the polyaspartic acid solid powder in a vacuum drying oven at 50-60°C for 4-6 hours to remove possible adsorbed moisture, improve its purity and reactivity, and facilitate its subsequent role in chelating metal ions and enhancing conductivity in the resistance reducing agent system.

[0068] Sodium carboxymethyl cellulose (CMC): Slowly add CMC into an appropriate amount of warm water (40-50°C) while stirring. Continue stirring for 30-60 minutes to fully dissolve it and form a uniform solution, so as to facilitate uniform mixing with other solid components during the ball milling process and play its thickening and stabilizing role.

[0069] Phosphogypsum: Phosphogypsum is crushed to reduce its particle size to 0.1-1.0 mm to increase its specific surface area. It is then rinsed with clean water 2-3 times to remove possible impurities and soluble salts. It is then dried at 80-100°C to constant weight to improve its purity and activity, allowing it to play a more effective role in regulating soil pH and providing nutrients to microorganisms.

[0070] Composite microbial flora: The microbial flora is embedded using the sodium alginate-calcium chloride system. The microbial flora is evenly dispersed in a sodium alginate solution (sodium alginate concentration is 2-3%), and then is gradually added dropwise into a calcium chloride solution (calcium chloride concentration is 1-2%) through a peristaltic pump to form gel microspheres, which embed and protect the microorganisms, improve their survival time and activity in the drag reducer, and before adding them into the ball mill tank, the embedded microbial flora is rinsed 1-2 times with normal saline to remove possible residual unreacted substances on the surface, ensuring its stability and functionality in the drag reducer system.

[0071] Sodium dodecylbenzenesulfonate: Sodium dodecylbenzenesulfonate is dissolved in an appropriate amount of deionized water to prepare a solution with a mass concentration of 10-15%, stirred evenly and reserved for use, so as to better play the role of its surfactant during the ball milling process, reduce the surface tension between various solid particles, and promote the dispersion and mixing of components.

[0072] Disodium ethylenediaminetetraacetate (EDTA-2Na): Before use, EDTA-2Na is ground into fine powder in a mortar and passed through a 80-100 mesh sieve to ensure that its particles are small and uniform, which is beneficial to fully contact and react with other components during the ball milling process, and better play its complexing activation and slow release effects on metal ions.

[0073] S2: The pretreated graphene nanosheets, barium titanate nanoparticles, metal-organic framework materials, polyvinyl butyral-sodium alginate composite hydrogel, polyaspartic acid, epoxy resin emulsion, sodium carboxymethylcellulose, phosphogypsum, composite microbial flora, sodium dodecylbenzenesulfonate, and disodium ethylenediaminetetraacetate are successively added into the ball mill tank of the ball mill, water and grinding balls are added, where the ball-to-material ratio is 3:1, the rotation speed of the ball mill is 300-500 rpm, and the ball milling time is 4-6 hours.

[0074] S3: The mixture after ball milling is transferred to a reaction kettle and continuously stirred and reacted at 50-60 °C for 2-3 hours to further cure and crosslink the epoxy resin emulsion, improve the overall strength and stability of the drag reducer, and at the same time promote the physical and chemical interactions between various components to form an environmentally friendly drag reducer product with stable performance and high efficiency;

[0075] S4: The reaction product of step S3 is cooled to room temperature, and excess water and bubbles are removed by vacuum filtration to obtain an environmentally friendly drag reducer paste.

[0076] The application of the environmentally friendly drag reducer suitable for sandy and desertified geological soils of the present invention includes:

[0077] Determine the construction area of the soil resistance reducer, drill holes at intervals of 0.5 - 1 meter in the construction area of the soil resistance reducer to form a grid-like hole network. Among them, the drilling depth is 1.0 - 1.5 meters, and the diameter of the hole is 5 - 10 centimeters.

[0078] After the drilling is completed, use equipment such as bulldozers and graders to level and clean the soil surface of the construction area, remove sundries such as floating sand, weeds, and stones on the surface, ensure that the soil surface is flat and obstacle-free, which is convenient for the operation of subsequent construction equipment and the uniform application of the soil resistance reducer. Then, use multiple rollers to preliminarily compact the soil. The rollers operate according to a certain driving route and overlapping width to ensure that the compaction degree of the entire construction area of the soil resistance reducer reaches 70% - 80%, creating good basic conditions for the construction of the soil resistance reducer. It should be noted that during actual construction, the operation of the equipment for site leveling and compaction (such as bulldozers, graders, and rollers) avoids the already drilled holes.

[0079] Dilute a part of the environmentally friendly soil resistance reducer with water according to a volume ratio of 1:1.5 - 1:2.5, and do not dilute the other part.

[0080] Inject the undiluted environmentally friendly soil resistance reducer into the pre-drilled holes through a pressure pump and a pipeline conveying system, with a pressure of 0.5 - 1.0 MPa and an injection speed of 1 - 2 L / min; specifically, precisely adjust through the pressure and flow regulating valves on the pressure pump, and arrange a special person to be responsible for observing and recording the injection situation of each drill hole. To ensure that the soil resistance reducer can fully fill the holes, when it is observed that the soil resistance reducer overflows above the holes, continue to maintain a certain injection pressure and a small injection volume (such as 0.5 L / min) and continuously inject for 1 - 2 minutes, then stop the injection, and cover an appropriate amount of soil above the holes (the covering thickness is about 10 - 15 centimeters) to prevent the volatilization and loss of the soil resistance reducer. At the same time, during the injection process, regularly check whether there is any leakage at the pipeline connection parts. If there is leakage, immediately stop the injection, repair the leakage point, and then continue the construction to ensure construction safety and the effective utilization of the soil resistance reducer.

[0081] The diluted environment-friendly resistance reducer is sprayed in layers on the resistance reducer construction area in a crisscross pattern, where the spraying amount is 3 - 5 liters per square meter. Specifically, according to the area and shape of the resistance reducer construction area, the entire area is divided into several small sub-areas. The size and shape of the sub-areas should take into account the operation range and efficiency of the spraying equipment, and try to make the spraying operation time of each sub-area relatively balanced to avoid frequent movement and start-stop of the equipment. For example, a rectangular construction area can be divided into multiple small rectangular sub-areas with equal widths along the length direction; within each sub-area, a crisscross pattern is adopted, that is, the first spraying is carried out along one direction of the sub-area (such as the long side direction), which can ensure the uniform distribution of the resistance reducer in one direction. Then, the second spraying is carried out in the vertical direction (such as the short side direction). Through the two cross-sprayings, the resistance reducer can cover the entire sub-area more evenly. For irregularly shaped sub-areas, the spraying route should be flexibly adjusted according to its specific shape to ensure that there are no missed areas. Between adjacent sub-areas, attention should be paid to the connection of spraying to avoid uneven spraying in the boundary areas; the spraying equipment is equipped with a flow control device, which can adjust the spraying speed of the resistance reducer according to the preset spraying amount. Determine that the required spraying amount of the resistance reducer per square meter is controlled at 3 - 5 liters per square meter, and then adjust the flow control device to the corresponding flow setting. During the spraying process, the operator should closely monitor the flow display of the equipment to ensure that the actual spraying amount meets the requirements; since factors such as the viscosity of the resistance reducer, the traveling speed of the spraying equipment, and the wear of the nozzle may affect the actual spraying amount, real-time monitoring is required during the spraying process. A flow monitoring sensor can be installed on the spraying equipment, or the actual spraying amount can be monitored by regularly measuring the thickness of the resistance reducer in the sprayed area. If it is found that the spraying amount deviates from the target value, promptly correct it by adjusting the traveling speed, spraying pressure or flow control device of the spraying equipment. For example, if the spraying amount is too much, the traveling speed of the equipment can be appropriately increased or the spraying pressure can be reduced; on the contrary, if the spraying amount is insufficient, the traveling speed can be reduced or the spraying pressure can be increased.

[0082] The resistance reducer construction area is rototilled and stirred, and then undiluted environment-friendly resistance reducer is injected again into the soil layer after rototilling and stirring according to the method of hole injection. Specifically, the operation of rototilling and stirring is carried out by multiple rototillers. The rototilling depth of the rototiller is 0.3 - 0.5 meters, the traveling speed of the rototiller is 0.5 - 1.0 m / s, and the rotational speed of the rototilling blade of the rototiller is 200 - 300 rpm.

[0083] After the injection and spraying of the environment-friendly resistance reducer are completed, the soil of the entire resistance reducer construction area is deeply plowed. Specifically, the operation of deep plowing is carried out by a deep plow. The plowing depth of the deep plow is 1.0 - 1.5 meters, and the traveling speed of the deep plow is 0.5 - 1.0 m / s.

[0084] After the deep tillage is completed, the soil is compacted by the method of layered compaction, and the compaction degree is 90-95%. Specifically, first, multiple small rammers are used to compact the deep soil (1.0-1.5 m), and the compaction times are 3-5 times. The rammers operate at a certain spacing (such as 1.0-1.5 m) and in a certain order to ensure that the deep soil is fully compacted. During the compaction process, attention should be paid to the impact energy and frequency of the rammer. Generally, the impact energy is controlled at 10-20 kJ, and the frequency is 10-15 times / min to avoid over-compaction resulting in soil compaction or damage to the structure of the resistance reducing agent. Then, gradually progress upward and compact the middle layer (0.5-1.0 m) and the surface layer (0-0.5 m) soil 5-8 times and 8-10 times respectively, so that the compaction degree of the soil finally reaches 90%-95%. After each layer of compaction is completed, a compaction degree detector is used to detect the compaction degree of the soil. If it is found that the compaction degree in an area does not meet the requirements, supplementary compaction is carried out in time to ensure the close combination of the resistance reducing agent and the soil, form a stable resistance reducing structure, and at the same time improve the mechanical properties of the soil to prevent the influence of soil settlement and deformation on the resistance reducing effect.

[0085] After construction is completed, an automatic irrigation system is set up. The irrigation system has intelligent control functions and can automatically start and stop irrigation according to the data real-time monitored by soil humidity sensors and the preset humidity range, achieving intelligent water management, maintaining the soil humidity between 20% - 30% for a duration of 2 - 3 weeks, providing a suitable growth environment for the microbial flora in the resistance reducing agent, promoting its reproduction and metabolic activities, and further optimizing the soil structure and electrical conductivity; during the maintenance period, the soil resistivity is measured every 3 - 5 days using a high-precision soil resistivity tester at multiple positions and depths; according to the monitored data, if it is found that the resistivity decrease is not obvious or does not reach the expected target, problem analysis is carried out in a timely manner to find out the possible causes of the problem, such as uneven mixing of the resistance reducing agent and the soil, insufficient activity of the microbial flora, inappropriate moisture content, etc. Corresponding remedial measures are taken for specific problems. For example, if it is found that the resistance reducing agent and the soil are not evenly mixed, deep tillage equipment can be arranged to plow and stir the soil again, and the tillage depth and method are adjusted according to the actual situation. If the activity of the microbial flora is insufficient, a special microbial nutrient can be added appropriately to activate the flora, and the type and dosage of the nutrient are selected and calculated according to the type of the microbial flora and the soil environmental conditions. If it is a moisture content problem, precise water regulation is carried out through the irrigation system, increasing or decreasing the irrigation water volume and irrigation frequency to ensure that the soil humidity is maintained within a suitable range, so as to ensure that the resistance reducing agent can fully exert its performance and achieve the expected resistance reduction effect; within a certain period (such as half a year to one year) after the resistance reduction project is put into use, continue to regularly monitor the soil resistivity and conduct an appearance inspection of the resistance reduction area. Measure the soil resistivity at a certain time interval (such as monthly or quarterly), observe the change trend of the resistivity, evaluate the long-term effectiveness and stability of the resistance reducing agent. At the same time, regularly conduct an appearance inspection of the resistance reduction area to observe whether there are abnormal situations such as ground settlement and cracks. If there are abnormalities, carry out cause analysis and treatment in a timely manner to ensure the safety and reliability of the resistance reduction project. In addition, observe and record the vegetation growth situation around the resistance reduction area, including indicators such as the type of vegetation, coverage rate, and growth height. Since some components in the resistance reducing agent (such as phosphogypsum, composite microbial flora, etc.) may have a positive impact on soil fertility and the microbial environment, thereby promoting vegetation growth, monitoring the vegetation can reflect the improvement effect of the resistance reducing agent on the soil ecological environment from the side.

[0086] The technical solutions of the present invention will be further elaborated through multiple examples and comparative examples as follows:

[0087] Example 1:

[0088] The environment-friendly resistance reducing agent includes:

[0089] 15 parts of nano-graphene, 8 parts of nano-barium titanate, 5 parts of metal-organic framework material, 10 parts of polyvinyl butyral-sodium alginate composite hydrogel, 5 parts of polyaspartic acid, 8 parts of phosphogypsum, 4 parts of composite microbial flora, 8 parts of epoxy resin emulsion (binder), 3 parts of sodium carboxymethyl cellulose (stabilizer), 2 parts of sodium dodecylbenzenesulfonate (surfactant), 2 parts of disodium ethylenediaminetetraacetate (activation assistant), and 20 parts of water. Here, 1 part corresponds to 10 grams by weight.

[0090] The preparation method of the environment-friendly drag reducer includes:

[0091] S1: Pretreatment of graphene nanosheets: Add graphene nanosheets to a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, stir and react at 60 °C for 2 hours for oxidation treatment; repeatedly wash the oxidized graphene nanosheets with deionized water until neutral, then add them to a hydrazine hydrate solution and carry out a reduction reaction at 80 °C for 1 hour; Pretreatment of barium titanate nanoparticles: Prepare tetrabutyl titanate ethanol solution and barium acetate ethanol solution respectively; under vigorous stirring at 800 rpm, slowly drip the tetrabutyl titanate ethanol solution into the barium acetate ethanol solution, and at the same time add glacial acetic acid as a catalyst to control the pH value of the solution at 3. After dripping, continue to stir for 1 hour to form a uniform sol; transfer the sol to a high-pressure reaction kettle and carry out a hydrothermal reaction at 150 °C for 12 hours; after the reaction is completed, naturally cool to room temperature, and obtain barium titanate nanoparticles through centrifugal separation, washing, and drying; Pretreatment of metal-organic framework materials: Use copper nitrate and terephthalic acid as raw materials, dissolve copper nitrate in a mixed solution of N,N-dimethylformamide and ethanol with a volume ratio of 1:1, and add acetic acid to adjust the acidity of the solution; add terephthalic acid to the above solution and disperse it by ultrasonic wave for 30 minutes; transfer the solution to a reaction kettle lined with polytetrafluoroethylene and carry out a solvothermal reaction at 120 °C for 24 hours; after the reaction is completed, cool to room temperature, wash repeatedly with N,N-dimethylformamide and ethanol, and finally dry in a vacuum drying oven at 80 °C for 12 hours to obtain blue metal-organic framework crystals; Pretreatment of polyvinyl butyral-sodium alginate composite hydrogel: Dissolve polyvinyl butyral in water, heat to 80 °C, and stir until completely dissolved to obtain a polyvinyl butyral solution; slowly add sodium alginate to the polyvinyl butyral solution, continue to stir for 30 minutes, then add a cross-linking agent, control the dosage of the cross-linking agent to be 1% of the mass of sodium alginate, and react at 50 °C for 1 hour to form a polyvinyl butyral-sodium alginate composite hydrogel; repeatedly wash the prepared polyvinyl butyral-sodium alginate composite hydrogel with deionized water, then dry at 40 °C, and then crush it;

[0092] S2: Add the pre-treated graphene nanosheets, barium titanate nanoparticles, metal-organic framework materials, polyvinyl butyral-sodium alginate composite hydrogel, polyaspartic acid, epoxy resin emulsion, sodium carboxymethyl cellulose, phosphogypsum, composite microbial flora, sodium dodecylbenzenesulfonate, and disodium ethylenediaminetetraacetate into the ball mill tank in sequence. Add water and grinding balls. Among them, the ball-to-material ratio is 3:1, the rotation speed of the ball mill is 300 rpm, and the ball milling time is 4 hours.

[0093] S3: Transfer the mixture after ball milling to a reaction kettle and continue stirring and reacting at 50 °C for 2 hours.

[0094] S4: Cool the reaction product of step S3 to room temperature, and remove excess water and bubbles by vacuum filtration to obtain an environmentally friendly drag reducer paste.

[0095] Example 2:

[0096] The environmentally friendly drag reducer includes:

[0097] 18 parts of nano-graphene, 10 parts of nano-barium titanate, 7 parts of metal-organic framework materials, 13 parts of polyvinyl butyral-sodium alginate composite hydrogel, 7 parts of polyaspartic acid, 10 parts of phosphogypsum, 5 parts of composite microbial flora, 10 parts of epoxy resin emulsion (binder), 4 parts of sodium carboxymethyl cellulose (stabilizer), 2.5 parts of sodium dodecylbenzenesulfonate (surfactant), 2.5 parts of disodium ethylenediaminetetraacetate (activation assistant), and 25 parts of water. Here, 1 part corresponds to 10 grams in weight.

[0098] The preparation method of the environmentally friendly drag reducer includes:

[0099] S1: Pretreatment of graphene nanosheets: Add graphene nanosheets into a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, stir and react at 70 °C for 2.5 hours for oxidation treatment; repeatedly wash the oxidized graphene nanosheets with deionized water until neutral, then add them into a hydrazine hydrate solution and carry out a reduction reaction at 90 °C for 1.5 hours; Pretreatment of barium titanate nanoparticles: Prepare tetrabutyl titanate ethanol solution and barium acetate ethanol solution respectively; under vigorous stirring at 900 rpm, slowly drip the tetrabutyl titanate ethanol solution into the barium acetate ethanol solution, and at the same time add glacial acetic acid as a catalyst to control the pH value of the solution at 3.5. After the dripping is completed, continue to stir for 1.5 hours to form a homogeneous sol; transfer the sol to a high-pressure reaction kettle and carry out a hydrothermal reaction at 180 °C for 18 hours; after the reaction is completed, naturally cool to room temperature, and obtain barium titanate nanoparticles through centrifugal separation, washing, and drying; Pretreatment of metal-organic framework materials: Using copper nitrate and terephthalic acid as basic raw materials, dissolve copper nitrate in a mixed solution of N,N-dimethylformamide and ethanol with a volume ratio of 1:1, and add acetic acid to adjust the acidity of the solution; add terephthalic acid to the above solution and disperse it by ultrasonic for 45 minutes; transfer the solution to a reaction kettle lined with polytetrafluoroethylene and carry out a solvothermal reaction at 135 °C for 36 hours; after the reaction is completed, cool to room temperature, wash repeatedly with N,N-dimethylformamide and ethanol, and finally dry at 90 °C in a vacuum drying oven for 18 hours to obtain blue metal-organic framework crystals; Pretreatment of polyvinyl butyral-sodium alginate composite hydrogel: Dissolve polyvinyl butyral in water, heat to 85 °C, and stir until completely dissolved to obtain a polyvinyl butyral solution; slowly add sodium alginate to the polyvinyl butyral solution, continue to stir for 45 minutes, then add a crosslinking agent, control the dosage of the crosslinking agent to be 1.5% of the mass of sodium alginate, and react at 55 °C for 1.5 hours to form a polyvinyl butyral-sodium alginate composite hydrogel; wash the prepared polyvinyl butyral-sodium alginate composite hydrogel repeatedly with deionized water, then dry at 45 °C, and then crush it.

[0100] S2: Add the pretreated graphene nanosheets, barium titanate nanoparticles, metal-organic framework materials, polyvinyl butyral-sodium alginate composite hydrogel, and polyaspartic acid, epoxy resin emulsion, sodium carboxymethyl cellulose, phosphogypsum, composite microbial flora, sodium dodecylbenzenesulfonate, disodium ethylenediaminetetraacetate into the ball mill pot in sequence, the ball-to-material ratio is 3:1, the rotation speed of the ball mill is 400 rpm, and the ball milling time is 5 hours.

[0101] S3: Transfer the mixture after ball milling to a reaction kettle and continue to stir and react at 55 °C for 2.5 hours.

[0102] S4: Cool the reaction product of step S3 to room temperature, and remove excess moisture and bubbles by vacuum filtration to obtain an environmentally friendly drag reducer paste.

[0103] Example 3:

[0104] The formula of the environmentally friendly drag reducer includes:

[0105] 20 parts of nano-graphene, 12 parts of nano-barium titanate, 8 parts of metal-organic framework material, 15 parts of polyvinyl butyral-sodium alginate composite hydrogel, 8 parts of polyaspartic acid, 12 parts of phosphogypsum, 6 parts of composite microbial flora, 12 parts of epoxy resin emulsion (binder), 5 parts of sodium carboxymethyl cellulose (stabilizer), 3 parts of sodium dodecyl benzene sulfonate (surfactant), 3 parts of disodium ethylenediaminetetraacetate (activation assistant), and 30 parts of water. Here, 1 part corresponds to 10 grams in weight.

[0106] The preparation method of the environmentally friendly drag reducer includes:

[0107] S1: Pretreatment of graphene nanosheets: Add graphene nanosheets into a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, stir and react at 80 °C for 3 hours for oxidation treatment; repeatedly wash the oxidized graphene nanosheets with deionized water until neutral, then add them into a hydrazine hydrate solution and carry out a reduction reaction at 100 °C for 2 hours; Pretreatment of barium titanate nanoparticles: Prepare tetrabutyl titanate ethanol solution and barium acetate ethanol solution respectively; under vigorous stirring at 1000 rpm, slowly drip the tetrabutyl titanate ethanol solution into the barium acetate ethanol solution, and at the same time add glacial acetic acid as a catalyst to control the pH value of the solution at 4. After dripping, continue to stir for 2 hours to form a uniform sol; transfer the sol to a high-pressure reaction kettle and carry out a hydrothermal reaction at 200 °C for 24 hours; after the reaction is completed, naturally cool to room temperature, and obtain barium titanate nanoparticles through centrifugal separation, washing, and drying; Pretreatment of metal-organic framework materials: Using copper nitrate and terephthalic acid as raw materials, dissolve copper nitrate in a mixed solution of N,N-dimethylformamide and ethanol with a volume ratio of 1:1, and add acetic acid to adjust the acidity of the solution; add terephthalic acid to the above solution and disperse it by ultrasonic for 60 minutes; transfer the solution to a reaction kettle lined with polytetrafluoroethylene and carry out a solvothermal reaction at 150 °C for 48 hours; after the reaction is completed, cool to room temperature and centrifuge and separate with N,N-dimethylformamide and ethanol repeatedly; Pretreatment of polyvinyl butyral-sodium alginate composite hydrogel: Dissolve polyvinyl butyral in water, heat to 90 °C, and stir until completely dissolved to obtain a polyvinyl butyral solution; slowly add sodium alginate to the polyvinyl butyral solution, continue to stir for 60 minutes, then add a crosslinking agent, control the dosage of the crosslinking agent to be 2% of the mass of sodium alginate, and react at 60 °C for 2 hours to form a polyvinyl butyral-sodium alginate composite hydrogel; repeatedly wash the prepared product with deionized water, then dry it at 50 °C, and then crush it.

[0108] S2: Add the pretreated graphene nanosheets, barium titanate nanoparticles, metal-organic framework materials, polyvinyl butyral-sodium alginate composite hydrogel, aspartic acid, epoxy resin emulsion, sodium carboxymethyl cellulose, phosphogypsum, composite microbial flora, sodium dodecylbenzenesulfonate, and disodium ethylenediaminetetraacetate into the ball mill pot in sequence, with a ball-to-material ratio of 3:1, the rotation speed of the ball mill is 500 rpm, and the ball milling time is 6 hours.

[0109] S3: Transfer the mixture after ball milling to a reaction kettle and continue to stir and react at 60 °C for 3 hours.

[0110] S4: Cool the reaction product in step S3 to room temperature, remove excess water and air bubbles through vacuum filtration to obtain an environmentally friendly drag reducer paste.

[0111] Comparative Example 1:

[0112] The resistance reducing agent includes:

[0113] 20 parts of coarse graphite particles (5-10 mesh), 10 parts of potassium chloride, 8 parts of ferrous sulfate, 3 parts of potassium dichromate, 15 parts of cement, 5 parts of calcium lignosulfonate and 40 parts of water. Here, 1 part corresponds to 10 grams in weight.

[0114] The preparation method of the resistance reducing agent includes:

[0115] First, pre-treat the coarse graphite particles. Place them in a muffle furnace and calcine at 650 °C for 2.5 hours to remove surface impurities and activate the graphite structure, improving the electrical conductivity. After taking out and cooling, ball mill at a speed of 250 rpm for 1.5 hours to refine the particles to 20-30 mesh, and sieve for standby; separately prepare saturated aqueous solutions of potassium chloride, ferrous sulfate and potassium dichromate. At 55 °C, use a magnetic stirrer to stir at 450 rpm for 40 minutes to fully dissolve them, then mix the three solutions and continue to stir for 18 minutes; slowly add calcium lignosulfonate to the above mixed solution, and at the same time stir at 350 rpm for 25 minutes to ensure uniform dispersion. Then add cement and continue to stir for 45 minutes until a uniform slurry is formed; finally, add the pre-treated graphite particles to the slurry and stir at 300 rpm for 1.5 hours to make the graphite particles evenly disperse in the system, obtaining the finished product of the resistance reducing agent. The entire preparation process needs to strictly control the temperature, time and stirring speed, and the operating environment needs to have ventilation facilities to discharge harmful gases (such as a small amount of chromic acid mist generated by the volatilization of potassium dichromate).

[0116] Comparative Example 2:

[0117] The resistance reducing agent includes:

[0118] 12 parts of zinc powder, 8 parts of lead dioxide, 18 parts of coke powder, 6 parts of sodium nitrite, 10 parts of bentonite, 15 parts of water glass (modulus 3.0-3.3) and 30 parts of water. Here, 1 part corresponds to 10 grams in weight.

[0119] The preparation method of the resistance reducing agent includes:

[0120] Put zinc powder and lead tetraoxide into a ball mill, add an appropriate amount of absolute ethanol (the total mass ratio of ethanol to metal powder is 1:2) as a grinding aid, with a ball-to-material ratio of 2:1, and mill at a speed of 350 rpm for 2.5 hours to fully mix the two and refine the particles. After ball milling, dry in a vacuum drying oven at 65 °C for 5 hours to remove ethanol; dry distill coke powder at 450 °C for 1.5 hours to remove volatile components, improve purity and stability, and sieve through a 35-mesh sieve for standby after cooling; prepare an aqueous solution of sodium nitrite, control the concentration at 35%, and ultrasonically treat it with an ultrasonic cleaner at 45 °C for 25 minutes to accelerate dissolution; slowly add bentonite to the water glass solution, and stir with an electric stirrer at 550 rpm at 55 °C for 40 minutes until a uniform colloid is formed; sequentially add the treated zinc powder-lead tetraoxide mixture, coke powder, and sodium nitrite solution to the bentonite-sodium silicate colloid, and stir at 450 rpm for 25 minutes each time after adding a component to ensure uniform mixing and obtain a resistance reducing agent slurry; the entire preparation process needs to be carried out in a fume hood to avoid inhaling heavy metal dust such as lead and zinc and volatile gases of sodium nitrite.

[0121] Construct the above Examples 1-3 and Comparative Examples 1 and 2 in the resistance reducing agent construction area using the application method of the present invention. Each example and each comparative example adopt a multi-point measurement method, that is, measure the resistance at different soil points and different depths in the resistance reducing agent construction area. The soil resistance of Examples 1-3 is 4-10 Ω, the soil resistance of Comparative Example 1 is 28-53 Ω, and the soil resistance of Comparative Example 2 is 33-67 Ω. It can be seen that the resistance reducing agent provided by the present invention is not only environmentally friendly, but also has an obvious resistance reducing effect on the soil, and the deviation range at different positions is small and the stability is strong. Moreover, measure the water retention rate of the resistance reducing agents of Examples 1-3 and Comparative Examples 1 and 2. The 24-hour water retention rate of Examples 1-3 can reach over 90%, while the 24-hour water retention rate of Comparative Example 1 is only 60-70%, and the 24-hour water retention rate of Comparative Example 2 is only 55-65%. The resistance reducing agent of the present invention has excellent water retention ability.

[0122] It should be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, commodity or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or equipment. Without further limitation, the element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, commodity or equipment including the said element.

[0123] Each embodiment in the present invention is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple. For the relevant parts, reference can be made to the partial description of the method embodiment.

[0124] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is exemplary only and is not intended to imply that the scope of the disclosure is limited to these examples; under the concept of the present disclosure, the technical features among the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of one or more embodiments of the present invention as described above, which are not provided in detail for the sake of brevity.

[0125] Although the present disclosure has been described in connection with specific embodiments of the present disclosure, many alternatives, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description.

[0126] One or more embodiments of the present invention are intended to cover all such alternatives, modifications, and variations that fall within the scope of the present invention. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of the present invention shall be included within the scope of the present disclosure.

Claims

1. An environmentally friendly drag reducing agent suitable for sandy soil, characterized in that: The environmentally friendly drag reducing agent comprises 15-20 parts of nano-graphene, 8-12 parts of nano-barium titanate, 5-8 parts of metal organic framework material, 10-15 parts of polyvinyl butyral-sodium alginate composite hydrogel, 5-8 parts of polyaspartic acid, 8-12 parts of phosphogypsum, 4-6 parts of composite microbial flora, 8-12 parts of binder, 3-5 parts of stabilizer, 2-3 parts of surfactant, 2-3 parts of activating aid and 20-30 parts of water; The binder is epoxy resin emulsion, and the stabilizer is sodium carboxymethyl cellulose; The surfactant is sodium dodecylbenzenesulfonate, and the activating auxiliary agent is disodium ethylenediaminetetraacetic acid.

2. A method for preparing an environmentally friendly drag reducing agent suitable for sandy soil according to claim 1, characterized in that: The preparation method comprises: S1: Pretreatment of graphene nanosheets, barium titanate nanoparticles, metal-organic framework materials, and polyvinyl butyral-sodium alginate composite hydrogel; S2: adding the pretreated graphene nanosheets, barium titanate nanoparticles, metal organic framework materials, polyvinyl butyral-sodium alginate composite hydrogel, polyaspartic acid, epoxy resin emulsion, sodium carboxymethyl cellulose, phosphogypsum, composite microbial flora, sodium dodecylbenzenesulfonate, and disodium ethylenediaminetetraacetic acid to the ball mill jar in sequence, adding water and grinding balls, wherein the ball-to-material ratio is 3:1, the speed of the ball mill is 300-500 rpm, and the ball milling time is 4-6 hours; S3: Transfer the ball-milled mixture to a reactor and continue stirring and reacting at 50-60°C for 2-3 hours; S4: Cool the reaction product of step S3 to room temperature, remove excess water and bubbles by vacuum filtration, and obtain an environmentally friendly drag reducing agent paste.

3. The method for preparing an environmentally friendly drag reducing agent suitable for sandy soil according to claim 2, characterized in that: In step S1, the pretreatment of the graphene nanosheets includes: The graphene nanosheets were added to a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and stirred at 60-80°C for 2-3 hours for oxidation treatment; The oxidized graphene nanosheets are repeatedly washed with deionized water until neutral, and then added into a hydrazine hydrate solution for reduction reaction at 80-100° C. for 1-2 hours.

4. The method for preparing an environmentally friendly drag reducing agent suitable for sandy soil according to claim 2, characterized in that: In step S1, the pretreatment of the barium titanate nanoparticles includes: Prepare tetrabutyl titanate ethanol solution and barium acetate ethanol solution respectively; Under vigorous stirring at 800-1000 rpm, slowly add the tetrabutyl titanate ethanol solution to the barium acetate ethanol solution, and add glacial acetic acid as a catalyst. Control the pH value of the solution between 3-4. After the addition is complete, continue stirring for 1-2 hours to form a uniform sol. Transfer the sol to a high-pressure reactor and perform a hydrothermal reaction at 150-200°C for 12-24 hours; After the reaction is completed, the mixture is naturally cooled to room temperature, and barium titanate nanoparticles are obtained by centrifugal separation, washing, and drying.

5. The method for preparing an environmentally friendly drag reducing agent suitable for sandy soil according to claim 2, characterized in that: In step S1, the pretreatment of the metal organic framework material includes: Copper nitrate and terephthalic acid are used as raw materials. The copper nitrate is dissolved in a mixed solution of N,N-dimethylformamide and ethanol in a volume ratio of 1:1, and acetic acid is added to adjust the acidity of the solution. Add terephthalic acid to the above solution and disperse it ultrasonically for 30-60 minutes; The solution was transferred to a polytetrafluoroethylene-lined reactor and subjected to a solvothermal reaction at 120-150°C for 24-48 hours; After the reaction is completed, the mixture is cooled to room temperature, centrifuged, repeatedly washed with N,N-dimethylformamide and ethanol, and finally dried in a vacuum drying oven at 80-100°C for 12-24 hours to obtain blue metal-organic framework crystals.

6. The method for preparing an environmentally friendly drag reducing agent suitable for sandy soil according to claim 2, characterized in that: In step S1, the pretreatment of the polyvinyl butyral-sodium alginate composite hydrogel includes: Dissolve polyvinyl butyral in water, heat to 80-90°C, and stir until completely dissolved to obtain a polyvinyl butyral solution; Slowly add sodium alginate to the polyvinyl butyral solution, continue stirring for 30-60 minutes, then add a crosslinker, controlling the amount of the crosslinker to be 1-2% of the mass of the sodium alginate, and react at 50-60°C for 1-2 hours to form a polyvinyl butyral-sodium alginate composite hydrogel; The prepared polyvinyl butyral-sodium alginate composite hydrogel was repeatedly washed with deionized water, then dried at 40-50° C., and then crushed.

7. An application of the environmentally friendly drag reducing agent suitable for sandy soil as claimed in claim 1, characterized in that: The applications include: Determine the soil resistance reducer application area and drill holes at intervals of 0.5-1 meters in the area to form a grid-like hole network. The drilling depth is 1.0-1.5 meters and the hole diameter is 5-10 centimeters. Level, clean and compact the soil surface in the area where the resistance reducing agent is applied, with a compaction degree of 70-80%; Dilute a portion of the environmentally friendly drag reducing agent with water in a volume ratio of 1:1.5-1:2.5, and do not dilute the other portion; Inject the undiluted environmentally friendly drag reducing agent into the pre-drilled hole through a pressure pump and pipeline delivery system at a pressure of 0.5-1.0 MPa and an injection rate of 1-2 L / min; Use a crisscross pattern to spray the diluted environmentally friendly drag reducing agent in layers on the drag reducing agent construction area, with a spraying volume of 3-5 liters per square meter; Carry out rotary tillage and stirring in the area where the resistance reducing agent is to be applied, and then inject undiluted environmentally friendly resistance reducing agent into the soil layer after rotary tillage and stirring by the hole injection method; After the injection and spraying of the environmentally friendly friction reducer is completed, the soil in the entire friction reducer construction area is deeply plowed; After deep tillage is completed, the soil is compacted by layering method with a compaction degree of 90-95%.

8. The use of the environmentally friendly drag reducing agent suitable for sandy soil according to claim 7, characterized in that: The rotary tillage and mixing operation is carried out by multiple rotary tillers, the rotary tillage depth of the rotary tiller is 0.3-0.5 meters, the travel speed of the rotary tiller is 0.5-1.0m / s, and the rotary blade speed of the rotary tiller is 200-300rpm; The deep plowing operation is carried out with a deep plowing plow. The plowing depth of the deep plowing plow is 1.0-1.5 meters, and the travel speed of the deep plowing plow is 0.5-1.0m / s.

Images