Environment-friendly resistance reducing agent suitable for Saggoga geological soil as well as preparation method and application of environment-friendly resistance reducing agent

Abstract

The invention belongs to the technical field of resistance reducing agents, and aims to solve the problems that an existing resistance reducing agent is not environment-friendly enough, easily affects the ecological environment and is poor in resistance reducing performance, so that ground vegetation and soil structures are damaged due to frequent construction. In order to achieve the purpose, the invention provides an environment-friendly resistance reducing agent suitable for Saggoga geological soil as well as a preparation method and application of the environment-friendly resistance reducing agent. The environment-friendly resistance reducing agent is prepared from 15 to 20 parts of nano graphene, 8 to 12 parts of nano barium titanate, 5 to 8 parts of a metal organic framework material, 10 to 15 parts of polyvinyl butyral-sodium alginate composite hydrogel, 5 to 8 parts of polyaspartic acid, 8 to 12 parts of phosphogypsum, 4 to 6 parts of compound microbial flora, 8 to 12 parts of a binder, 3 to 5 parts of a stabilizer and 2 to 3 parts of a surfactant. 2-3 parts of an activating auxiliary agent and 20-30 parts of water. The resistance reducing agent disclosed by the invention does not contain heavy metal ions and toxic and harmful substances, is environment-friendly, does not influence the ecological environment, has good water retention performance, and can be used for decomposing organic matters in soil, releasing conductive ions and improving and maintaining the conductivity of the resistance reducing agent.

Description

Technical Field

[0001] The invention relates to the technical field of drag reducing agents, and in particular to an environmentally friendly drag reducing agent suitable for Shagohuang geological soil, and a preparation method and application thereof. Background Art

[0002] With the acceleration of global industrialization and urbanization, infrastructure construction in many fields such as power transmission, communication base stations, and petrochemicals continues to expand to the vast desert areas. In these areas, the soil resistivity is usually high, which brings great challenges to the design and implementation of grounding systems. Existing resistance reduction methods often have many drawbacks and are difficult to meet the needs of modern engineering for efficient, environmentally friendly, and sustainable resistance reduction.

[0003] Under the geological conditions of Shagohuang, the high resistivity of the soil is mainly due to its special physical and chemical properties. This type of soil has coarse particles, high porosity, low water content and lack of conductive ions, making it difficult for current to conduct in it. In the early days, in order to reduce 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 cyanide, halide, etc.), which will not only cause serious pollution to the soil environment, destroy the ecological balance of the soil, and affect the local vegetation growth and microbial community, but also with the action of rainwater erosion, these harmful substances may also infiltrate into groundwater bodies, pollute water resources, and then threaten the surrounding ecosystem and human health.

[0004] In addition, the resistance reduction effects of existing resistance reduction measures are often not long-lasting and stable enough. Due to the harsh climatic conditions in the Shagohuang area, such as high temperature, drought, strong winds, etc., the resistance reduction agent is easy to volatilize, lose, or be adsorbed and fixed by soil particles, causing its conductive properties to decline rapidly over time, requiring frequent maintenance and repair, increasing project costs and operational risks. Moreover, some existing construction methods are difficult to implement in the Shagohuang area, such as large-scale land turning and deep excavation operations, which not only consume a lot of manpower, material and financial resources, but also cause irreversible damage to surface vegetation and soil structure, aggravating environmental problems such as land desertification and soil erosion, and further damaging the fragile local ecological environment.

[0005] In view of this, the art needs an environmentally friendly drag reducing agent suitable for Shagohuang geological soil and a preparation method and application thereof to solve the above problems. Summary of the invention

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

[0007] In a first aspect, the present invention provides an environmentally friendly drag reducing agent suitable for Shagohuang geological soil, the environmentally friendly drag reducing agent comprising 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 activating aid and 20-30 parts of water.

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

[0009] In certain preferred embodiments, the surfactant is sodium dodecylbenzene sulfonate, and the activating aid is disodium ethylenediaminetetraacetate.

[0010] The environmentally friendly drag reducing agent suitable for Shagohuang geological soil of the present invention has the following beneficial effects:

[0011] In the environmentally friendly drag reducing agent of the present invention, through the synergistic effect of multiple high-efficiency conductive components such as nano-graphene, nano-barium titanate and metal organic framework materials, these materials have unique microstructures and electrical properties, can build an efficient conductive network in the Shagohuang soil, effectively reduce the resistivity of the soil, and significantly improve the current conduction capacity; the drag reducing agent completely abandons the common heavy metal ions (such as mercury, cadmium, lead, etc.) and toxic and harmful substances (such as cyanide, halide, etc.) in traditional drag reducing agents, and avoids the pollution of the fragile soil ecological environment in the Shagohuang area from the source, which 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, and ensures the safety of surrounding water resources; components such as polyvinyl butyral-sodium alginate composite hydrogel and polyaspartic acid have good water retention properties, can absorb and store a certain amount of water, and improve the water content of the Shagohuang soil. It improves the conductivity of the soil and reduces the evaporation and loss of water, creating a relatively moist environment for plant growth and microbial activity. The addition of phosphogypsum can adjust the pH of the soil, supplement calcium, sulfur and other elements in the soil, improve the compaction of the soil, enhance soil fertility, promote the optimization of soil structure, and is conducive to the recovery and growth of vegetation, further improving the comprehensive improvement effect of the resistance reducer on the Shagohuang soil; the presence of complex microbial flora can continue metabolic activities in the soil, decompose organic matter in the soil, release conductive ions, and maintain the conductivity of the resistance reducer. At the same time, its metabolites can also improve the soil structure, enhance the binding force between the resistance reducer and soil particles, and reduce the volatilization, loss and adsorption fixation of the resistance reducer due to climatic factors (such as high temperature, drought, strong wind, etc.), making the resistance reduction effect more lasting and stable, reducing the maintenance cost and operation risk of the project, and improving the reliability and stability of infrastructure operation in the Shagohuang area.

[0012] In a second aspect, the present invention provides a method for preparing the above-mentioned environmentally friendly drag reducing agent suitable for Shagohuang geological soil, the preparation method comprising:

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

[0014] 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 dodecylbenzene sulfonate, and disodium ethylenediaminetetraacetate to the ball mill of the ball mill in sequence, adding water and grinding balls, wherein 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: transferring the ball-milled mixture into a reactor and continuing to stir and react at 50-60° C. for 2-3 hours;

[0016] 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.

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

[0018] The graphene nanosheets are 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;

[0019] The oxidized graphene nanosheets are repeatedly washed with deionized water until they are neutral, and then added into a hydrazine hydrate solution for reduction reaction at 80-100° C. for 1-2 hours.

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

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

[0022] Under vigorous stirring at 800-1000 rpm, the tetrabutyl titanate ethanol solution is slowly added dropwise to the barium acetate ethanol solution, and glacial acetic acid is added as a catalyst, and the pH value of the solution is controlled between 3-4. After the addition is completed, stirring is continued for 1-2 hours to form a uniform sol;

[0023] The sol is transferred to a high pressure reactor and subjected to a hydrothermal reaction at 150-200° C. for 12-24 hours;

[0024] 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.

[0025] In certain preferred embodiments, in step S1, pretreatment of the metal organic framework material comprises:

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

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

[0028] The solution was transferred to a polytetrafluoroethylene-lined reactor and subjected to a solvothermal reaction at 120-150°C for 24-48 hours;

[0029] 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.

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

[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 amount of the crosslinking agent to be 1-2% of the mass of the sodium alginate, react at 50-60° C. for 1-2 hours to form a polyvinyl butyral-sodium alginate composite hydrogel;

[0033] The prepared polyvinyl butyral-sodium alginate composite hydrogel was repeatedly washed with deionized water, then dried at 40-50° C., and then crushed.

[0034] The preparation method of the environmentally friendly drag reducing agent suitable for Shagohuang geological soil of the present invention has the following beneficial effects:

[0035] In the preparation method of the environmentally friendly drag reducing agent of the present invention, specific pretreatment methods are adopted according to the characteristics of different raw materials, such as redox treatment of graphene nanosheets, introduction of functional groups such as carboxyl and hydroxyl groups on their surfaces and then reduction, thereby improving the dispersibility and conductivity of graphene in the drag reducing agent system; barium titanate nanoparticles are precisely controlled by the sol-gel method and hydrothermal reaction process to obtain products with uniform particle size and good activity; metal organic framework materials are solvent thermally synthesized and post-treated to ensure that they have high specific surface area and suitable pore structure; polyvinyl butyral-sodium alginate composite hydrogel has good water retention and bonding properties by optimizing the cross-linking reaction conditions. These pretreatment steps lay a solid foundation for the subsequent preparation of high-performance drag reducing agents, ensuring that each raw material can give full play to its function and improve the overall performance of the drag reducing agent; a ball mill is used for mixed grinding, and the rotation speed, ball-to-material ratio and ball milling time of the ball mill are precisely controlled to make various raw materials with different properties have mechanical forces. Under the action of the ball mill, highly uniform mixing and physical and chemical reactions at the microscopic level are achieved, and the interaction and synergistic effect between the components are promoted. The stirring reaction step in the reactor after ball milling further optimizes the overall performance of the drag reducer, makes the epoxy resin emulsion solidify and cross-link, stabilizes the structure of the drag reducer, ensures the quality stability and performance consistency of the drag reducer, avoids the fluctuation of the drag reduction effect and the problem of local performance difference caused by uneven mixing, and improves the reliability and practicality of the drag reducer; the solvents, reagents, etc. used in the entire preparation process are reasonably selected and strictly controlled to avoid the use of toxic, harmful and highly volatile chemicals, reduce pollution to the environment and harm to the health of operators, and 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 large-scale production, ensuring the stability and consistency of the performance of different batches of drag reducer products, and providing technical guarantee for the industrial production and wide application of drag reducers.

[0036] In a third aspect, the present invention provides an application of the above-mentioned environmentally friendly drag reducing agent suitable for Shagohuang geological soil, the application comprising:

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

[0038] Level, clean and compact the soil surface in the area where the resistance reducing agent is applied, with a compaction degree of 70-80%;

[0039] 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;

[0040] Inject the undiluted environmentally friendly drag reducing agent into the pre-drilled hole through a pressure pump and a pipeline delivery system at a pressure of 0.5-1.0MPa and an injection speed of 1-2L / min;

[0041] The diluted environmentally friendly drag reducing agent is sprayed in layers on the drag reducing agent construction area in a crisscross manner, wherein the spraying amount is 3-5 liters per square meter;

[0042] 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 again into the soil layer after rotary tillage and stirring according to the hole injection method;

[0043] After the injection and spraying of the environmentally friendly drag reducing agent is completed, the soil in the entire drag reducing agent construction area is deeply plowed;

[0044] After deep tillage is completed, the soil is compacted by layering method with a compaction degree of 90-95%.

[0045] In certain preferred embodiments, the rotary tillage and mixing operation is performed using 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 0.5-1.0 m / s, and the rotary blade speed of the rotary tiller is 200-300 rpm;

[0046] 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.

[0047] The application of the environmentally friendly drag reducing agent suitable for Shagohuang geological soil of the present invention has the following beneficial effects:

[0048] In the application of the environmentally friendly drag reducing agent of the present invention, holes are drilled in the drag reducing agent construction area at a specific spacing and depth to form a grid-like hole network, which increases the contact area and penetration channel between the drag reducing agent and the soil, allowing the drag reducing agent to penetrate deep into the soil, effectively solving the problem that the drag reducing agent is not easy to penetrate due to the coarse particles and high porosity of the Shagohuang soil, and improving the uniformity and stability of the drag reducing effect; a construction method is adopted in which a part of the environmentally friendly drag reducing agent is diluted and sprayed in layers, and then combined with rotary tillage and stirring, so that the drag reducing agent can form a uniform conductive layer on the soil surface and fully mix with the soil particles, ensuring that the drag reducing agent can cover the surface of each soil particle, improving the utilization efficiency and drag reducing effect of the drag reducing agent, and then injecting the undiluted drag reducing agent into the holes again, further strengthening the conductive network in the deep soil layer, forming a multi-level drag reducing structure, effectively coping with the complex soil conditions in the Shagohuang area, and improving the stability and reliability of the grounding system; after the drag reducing agent is injected and sprayed, a deep plow is used for deep tillage to fully mix the drag reducing agent with the soil, ensuring that the drag reducing agent is The uniform distribution of the drag reducer in the soil forms a continuous conductive path, and then the soil is compacted by layered compaction to make the drag reducer tightly combined with the soil, which not only improves the density and mechanical properties of the soil, prevents the drag reduction effect from being affected by soil settlement and deformation, but also enhances the stability of the drag reduction structure, reduces the volatilization and loss of the drag reducer under adverse climatic conditions, ensures the long-term effectiveness and stability of the drag reduction project, and provides a reliable grounding guarantee for the infrastructure construction in the Shagohuang area; the entire application process focuses on environmental protection of the construction area, and the soil surface is leveled and cleaned before construction to avoid excessive damage to the surface vegetation. After construction, reasonable compaction and maintenance measures are taken to facilitate the recovery and growth of vegetation, reducing the occurrence of environmental problems such as soil erosion and land desertification. At the same time, due to the environmental protection characteristics of the drag reducer itself and the scientific nature of the construction method, the drag reduction project minimizes the impact on the ecological environment of the Shagohuang area while achieving efficient drag reduction, which is in line with the principle of sustainable development and provides a balanced solution for the long-term development and ecological protection of the 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, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0050] Figure 1 The present invention is a flow chart of a method for preparing an environmentally friendly drag reducing agent suitable for Shagohuang geological soil. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0052] Based on the problems pointed out in the background technology that the existing drag reducing agents are not environmentally friendly and are easy to affect the ecological environment, and the poor drag reducing performance leads to frequent construction that will damage the surface vegetation and soil structure, the present invention provides an environmentally friendly drag reducing agent suitable for Shagohuang geological soil and its preparation method and application, aiming to make the drag reducing agent adopt environmentally friendly components, completely abandon the common heavy metal ions (such as mercury, cadmium, lead, etc.) and toxic and harmful substances (such as cyanide, halide, etc.) in traditional drag reducing agents, avoid the pollution of the fragile soil ecological environment in Shagohuang area from the source, and the drag reducing agent has good water retention performance, can absorb and store a certain amount of water, improve Shagohuang geological soil. It can reduce the moisture content of wasteland soil, improve the conductivity of soil, reduce the evaporation and loss of water, and create a relatively moist environment for plant growth and microbial activity. In addition, the resistance reducer also decomposes organic matter in the soil, releases conductive ions, and maintains the conductivity of the resistance reducer. At the same time, its metabolites can also improve the soil structure, enhance the binding force between the resistance reducer and soil particles, and reduce the volatilization, loss and adsorption and fixation of the resistance reducer due to climatic factors (such as high temperature, drought, strong wind, etc.), making the resistance reduction effect more lasting and stable, reducing the maintenance cost and operation risk of the project, and improving the reliability and stability of infrastructure operation in the Shagohuang area.

[0053] The environment-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.

[0054] Preferably, the binder is epoxy resin emulsion, the stabilizer is sodium carboxymethyl cellulose, the surfactant is sodium dodecylbenzene sulfonate, and the activating aid is disodium ethylenediaminetetraacetate.

[0055] It should be noted that, in the above, the raw material of nanographene is graphene nanosheets, which have excellent electrical properties, and its two-dimensional sheet structure can provide efficient electron conduction channels, significantly enhancing the conductivity of the drag reducer; nanobarium titanate can improve the dielectric properties of the drag reducer, promote the polarization and movement of charges, and the small size effect of nanoparticles enables it to better fill the gaps in other materials and optimize 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 to further enhance the overall conductive properties of the drag reducer; the water retention and ion sustained release system is achieved through polyvinyl butyral (PVB)-seaweed The film-forming property of the drag reducing agent is realized by sodium alginate composite hydrogel and polyaspartic acid (PASP). PVB provides good film-forming property and mechanical strength. Sodium alginate has abundant carboxyl groups, which can absorb a large amount of water and chelate with metal ions. Polyaspartic acid (PASP) can chelate metal ions in the soil to prevent their precipitation and loss. At the same time, its own ionization characteristics also help to improve the conductivity of the soil and promote the absorption of nutrients by plant roots, which is beneficial to improve the soil ecological environment in the Shagohuang area. Sodium carboxymethyl cellulose (CMC) is used as a thickener and stabilizer to increase the viscosity and stability of the drag reducing agent, prevent the sedimentation and stratification of the components during storage and use, and ensure the uniformity of the drag reducing agent. Uniformity and consistency, and CMC is a natural cellulose derivative with good biocompatibility and degradability; phosphogypsum is rich in calcium, sulfur and other elements, which can adjust the pH of the soil, improve the compaction of the soil, and provide a certain source of nutrients for microorganisms, promote the growth and reproduction of microorganisms, and are beneficial to the optimization of soil structure and the improvement of electrical conductivity; the composite microbial flora is composed of a variety of functional microorganisms, such as nitrogen-fixing bacteria, phosphate-dissolving bacteria, photosynthetic bacteria, etc. These microorganisms can carry out a series of metabolic activities in the soil, decompose organic matter in the soil, release more conductive ions, and enhance the fertility and air permeability of the soil. In addition, the microbial flora can be specially embedded to make It has better activity and stability in the drag reducing agent, ensuring that it can continue to play a role after construction. For example, the sodium alginate-calcium chloride system is used in the embedding process, and the microbial flora is evenly dispersed in the sodium alginate solution, and then added dropwise to the calcium chloride solution to form gel microspheres, which embed and protect the microorganisms and increase their survival time and activity in the drag reducing agent; sodium dodecylbenzene sulfonate, as an anionic surfactant, can reduce the surface tension between the solid particles, improve its dispersibility in the drag reducing agent system, prevent particle agglomeration, and ensure that all components can fully play their role. At the same time, it also has a certain cleaning and dispersing effect on some impurities such as oil in the soil, which is conducive to the close contact between the drag reducing agent and the soil;Disodium ethylenediaminetetraacetate (EDTA-2Na) can form a stable complex with metal ions, activate and slow-release the metal ions in the resistance reducing agent, improve its conductivity, and also help prevent the precipitation and passivation of metal ions in the soil, thus maintaining the long-term effectiveness of the resistance reducing agent. ;

[0056] like Figure 1 As shown, the preparation method of the environmentally friendly drag reducing agent suitable for Shagohuang geological soil of the present invention comprises:

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

[0058] Preferably, in step S1, pre-treating the graphene nanosheets includes:

[0059] The graphene nanosheets are 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 oxidation process can introduce oxygen-containing functional groups such as carboxyl (-COOH) and hydroxyl (-OH), which can improve the hydrophilicity and surface activity of the graphene nanosheets, making them easier to disperse in the subsequent drag reducing agent system, and can react chemically with other components to enhance the overall performance of the drag reducing agent. In order to ensure that the degree of oxidation reaction is appropriate, an appropriate amount of oxygen-containing functional groups such as carboxyl (-COOH) and hydroxyl (-OH) are introduced. During the reaction process, a variety of methods can be used for monitoring and control. 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 speaking, as the oxidation reaction proceeds, at 1700-1750cm -1 The C=O stretching vibration absorption peak of the carboxyl group will appear nearby, at 3200-3600cm -1The OH stretching vibration absorption peak of the hydroxyl group will appear in the range, and the intensity of the peak will gradually increase with the extension of the reaction time. When the absorption peak intensity of these functional groups is monitored to reach the expected range, the reaction can be stopped to avoid excessive oxidation leading to destruction of the graphene nanosheet structure and degradation of performance; the oxidized graphene nanosheet is repeatedly washed with deionized water (the amount of deionized water is generally 10-15 times the volume of the reaction solution) until it is neutral, and then added to a hydrazine hydrate solution (depending on the mass of the oxidized graphene nanosheet and the required degree of reduction, the mass ratio of hydrazine hydrate to the oxidized graphene nanosheet is generally 1:2-1:3), and 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 400-600rpm, ensure that hydrazine hydrate is fully in contact with graphene oxide nanosheets and undergo a reduction reaction; after the reduction reaction is completed, cool the reaction product to room temperature, collect the precipitate by centrifugation again, and wash it alternately with a large amount of deionized water and anhydrous ethanol for 3-5 times to remove unreacted hydrazine hydrate and other impurities. Finally, transfer the washed graphene nanosheets to a vacuum drying oven and dry them at 50-60°C for 12-24 hours to obtain dried pretreated graphene nanosheets. During the vacuum drying process, control the vacuum degree (generally 0.05-0.1MPa) and drying time to ensure that the graphene nanosheets are completely dried and no agglomeration occurs. The obtained product should have good dispersibility and high conductivity.

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

[0061] Prepare a tetrabutyl titanate ethanol solution and a barium acetate ethanol solution respectively; slowly drop the tetrabutyl titanate ethanol solution into the barium acetate ethanol solution under vigorous stirring at 800-1000 rpm, control the drop speed at 1-2 drops / second, add glacial acetic acid as a catalyst, control the pH value of the solution between 3-4, continue stirring for 1-2 hours after the drop addition is completed, and form a uniform sol; transfer the prepared sol to a polytetrafluoroethylene-lined autoclave, and control the filling degree at 60-80% to ensure the reaction During the reaction process, there is enough space for the reaction to proceed, and at the same time, the potential safety hazard of excessive pressure caused by excessive filling is avoided. After the reactor is sealed, it is placed in an oven preheated to 150-200°C for hydrothermal reaction for 12-24 hours. During the hydrothermal reaction, the temperature and pressure in the reactor will gradually increase, promoting the nucleation and growth of barium titanate nanoparticles; after the hydrothermal reaction is completed, the reactor is taken out of the oven and naturally cooled to room temperature. After the reactor is completely cooled, the reactor is opened and the reaction product is poured into a centrifuge tube. In the reaction mixture, an appropriate amount of anhydrous ethanol and deionized water (volume ratio 1:1) are added, and the mixture is centrifuged at a speed of 8000-10000 rpm for 10-15 minutes using a high-speed centrifuge, the supernatant is removed, the precipitate is collected, and the above washing steps are repeated 3-5 times to completely remove the impurity ions adsorbed on the surface of the reaction product and the unreacted raw materials, and then the washed precipitate is transferred to a vacuum drying oven and dried at 60-80° C. for 12-24 hours to obtain a dry barium titanate nanoparticle powder; X-ray diffraction (XR D) instrument to perform crystal form analysis on the prepared barium titanate nanoparticles, a small amount of dried sample is evenly spread on the sample stage, and a CuKα radiation source (λ=0.15406nm) is used to scan in the 2θ range of 20°-80°, and the scanning speed is 5°-10° / min. The crystal phase structure of the product is determined by comparing with the standard barium titanate XRD spectrum, and the grain size is calculated using the Scherrer formula based on the half-height width of the diffraction peak to ensure that the particle size is within the range of 20-50nm and has good crystallinity.

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

[0063] Copper nitrate and terephthalic acid are used as raw materials, copper nitrate is dissolved in a mixed solution of N,N-dimethylformamide (DMF) and ethanol in a volume ratio of 1:1, acetic acid is added to adjust the acidity of the solution, for example, pH=3.5-4.5; terephthalic acid is added to the above solution, and ultrasonic dispersion is performed for 30-60 minutes at a frequency of kHZ; the solution is transferred to a polytetrafluoroethylene-lined reactor, and the filling degree is controlled at 60-70% to reserve sufficient space for solvent volatilization and crystal growth during the reaction process, while ensuring the safe use of the reactor After sealing the reactor, place it in an oven preheated to 120-150°C for solvent thermal reaction for 24-48 hours. During the reaction, the temperature and pressure in the reactor will gradually increase. The solvent DMF and ethanol act as reaction media under high temperature and high pressure to promote the coordination reaction between copper nitrate and terephthalic acid, forming the nucleus of MOFs and gradually growing into crystals. After the solvent thermal reaction is completed, take the reactor out of the oven and cool it naturally to room temperature. After the reactor is completely cooled, carefully open the reactor and pour the reaction product into a centrifuge tube. First, add an appropriate amount of DMF, use a high-speed centrifuge to centrifuge at a speed of 8000-10000rpm 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 steps with ethanol 3-5 times to further remove the residual DMF and other impurities to ensure the purity of the MOFs crystals; transfer the washed MOFs crystals to a vacuum drying oven and dry them at 80-100℃ for 12-24 hours. During the drying process, the vacuum degree is controlled to be 0 .08-0.1MPa, ensuring that the MOFs crystals are completely dry and do not agglomerate. The dried MOFs crystals are blue and have a regular crystal morphology. The specific surface area and pore size distribution of the MOFs crystals are measured using a specific surface area and pore size analyzer (BET). A small amount of dried MOFs samples are pretreated under vacuum conditions to remove the gas and impurities adsorbed on the sample surface. Then, nitrogen adsorption-desorption experiments are performed at liquid nitrogen temperature. The specific surface area and pore size distribution of the samples are calculated according to the BET theory and the Barrett-Joyner-Hal enda (BJH) method to ensure that the specific surface area can reach 1000-2000m 2 / g, and the pore size distribution is in the range of 1-3nm, which meets the expected performance indicators, ensuring that MOFs can fully exert the advantages of their porous structure in the resistance reduction agent system, such as adsorbing and storing conductive ions, optimizing conductive pathways, etc.

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

[0065] The method comprises the following steps: dissolving polyvinyl butyral (PVB) in water, heating the solution to 80-90° C., and stirring the solution until the solution is completely dissolved to obtain a polyvinyl butyral solution; slowly adding sodium alginate into the polyvinyl butyral solution, continuing stirring for 30-60 minutes, and then adding a crosslinking agent (such as glutaraldehyde), wherein the amount of the crosslinking agent is controlled to be 1-2% of the mass of the sodium alginate, and reacting the solution 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, taking out the prepared hydrogel, and placing the hydrogel in a large amount of deionized water for soaking and washing. 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, and the unreacted cross-linking agent and other impurities in the hydrogel are removed by multiple soaking and water replacement; 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 the destruction of the hydrogel structure or the degradation of the performance due to excessively high temperature. The dried hydrogel is in block form, which 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 drag 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 ingredients 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, then rinsed with clean water 2-3 times to remove possible impurities and soluble salts, and then dried at 80-100°C to constant weight to improve its purity and activity, so that it can play a more effective role in regulating soil pH and providing nutrients for microorganisms.

[0070] Composite microbial flora: The sodium alginate-calcium chloride system is used to encapsulate the microbial flora. The microbial flora is evenly dispersed in a sodium alginate solution (sodium alginate concentration is 2-3%), and then added dropwise into a calcium chloride solution (calcium chloride concentration is 1-2%) through a peristaltic pump to form gel microspheres to encapsulate and protect the microorganisms, thereby increasing their survival time and activity in the drag reducing agent. Before adding the ball mill, the embedded microbial flora is rinsed 1-2 times with physiological saline to remove any unreacted substances that may remain on the surface, thereby ensuring their stability and functionality in the drag reducing agent system.

[0071] Sodium dodecylbenzene sulfonate: Dissolve sodium dodecylbenzene sulfonate in an appropriate amount of deionized water to prepare a solution with a mass concentration of 10-15%, stir it evenly and set aside so that it can better play the role of surfactant in the ball milling process, reduce the surface tension between the solid particles, and promote the dispersion and mixing of the components.

[0072] Disodium ethylenediaminetetraacetate (EDTA-2Na): Before use, grind EDTA-2Na into fine powder in a mortar and pass it through an 80-100 mesh sieve to ensure that its particles are fine and uniform, which is conducive to full contact and reaction with other ingredients during the ball milling process, and better exerts its complexing activation and sustained 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 carboxymethyl cellulose, phosphogypsum, composite microbial flora, sodium dodecylbenzene sulfonate and disodium ethylenediaminetetraacetic acid are sequentially added into the ball mill jar of the ball mill, and water and grinding balls are added, wherein the ball-to-material ratio is 3:1, the rotation speed of the ball mill is 300-500rpm, and the ball milling time is 4-6 hours.

[0074] S3: After the ball milling, the mixture is transferred to a reactor, and the reaction is continued under stirring at 50-60°C for 2-3 hours to further solidify and crosslink the epoxy resin emulsion, thereby improving the overall strength and stability of the drag reducer, and promoting the physical and chemical effects between the components to form an environmentally friendly drag reducer product with stable performance and high efficiency;

[0075] 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.

[0076] The application of the environmentally friendly drag reducing agent suitable for Shagohuang geological soil of the present invention includes:

[0077] Determine the construction area of ​​the soil resistance reducing agent, drill holes in the construction area at a spacing of 0.5-1 meter to form a grid-like hole network, where 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 bulldozers, graders and other equipment to level and clean the soil surface in the construction area, remove floating sand, weeds, stones and other debris on the surface, ensure that the soil surface is flat and free of obstacles, and facilitate the operation of subsequent construction equipment and the uniform application of the drag reducing agent. Then, use multiple rollers to carry out preliminary compaction of the soil. The rollers operate according to a certain driving route and overlapping width to ensure that the compaction degree of the entire drag reducing agent construction area reaches 70%-80%, creating good basic conditions for the construction of the drag reducing agent. It should be noted that in actual construction, the operation of site leveling and compaction equipment (such as bulldozers, graders and rollers) avoids the holes that have been drilled.

[0079] 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.

[0080] Inject undiluted environmentally friendly drag reducing agent into the pre-drilled holes through a pressure pump and a pipeline delivery system at a pressure of 0.5-1.0MPa and an injection speed of 1-2L / min. Specifically, the pressure and flow regulating valves on the pressure pump are used for precise adjustment, and a dedicated person is assigned to observe and record the injection situation of each borehole. To ensure that the drag reducing agent can fully fill the holes, when it is observed that the drag reducing agent overflows above the holes, continue to maintain a certain injection pressure and a small amount of injection volume (such as 0.5L / min) for 1-2 minutes, then stop the injection, and cover the holes with an appropriate amount of soil (covering thickness is about 10-15 cm) to prevent the drag reducing agent from volatilizing and losing. At the same time, during the injection process, regularly check whether there is a leak at the pipeline connection. If there is a leak, stop the injection immediately, repair the leak point and continue the construction to ensure construction safety and effective use of the drag reducing agent.

[0081] The diluted environmentally friendly drag reducing agent is sprayed in layers on the drag reducing agent construction area in a criss-cross manner, with a spraying volume of 3-5 liters per square meter; specifically, according to the area and shape of the drag reducing agent construction area, the entire area is divided into several small partitions. The size and shape of the partitions should take into account the operating range and efficiency of the spraying equipment, and the spraying operation time of each partition should be relatively balanced as much as possible to avoid frequent movement and start-stop of the equipment. For example, a rectangular construction area can be divided into multiple small rectangular partitions of equal width in the length direction; in each partition, a criss-cross manner is adopted, that is, the first spraying is carried out along one direction of the partition (such as the long side direction), which can Ensure that the drag reducing agent is evenly distributed in one direction, and then spray it a second time in the vertical direction (such as the short side direction). Through two cross spraying, the drag reducing agent can cover the entire partition more evenly. For irregularly shaped partitions, the spraying route should be flexibly adjusted according to its specific shape to ensure that there is no missed area. Between adjacent partitions, attention should be paid to the connection of spraying to avoid uneven spraying in the boundary area; the spraying equipment is equipped with a flow control device, which can adjust the spraying speed of the drag reducing agent according to the pre-set spraying amount, and determine that the required drag reducing agent spraying amount per square meter is controlled at 3-5 liters / square meter, and then adjust the flow control device to the corresponding flow setting. During the spraying process, the operator should pay close attention to the flow display of the equipment to ensure that the actual spraying volume meets the requirements; since factors such as the viscosity of the drag reducer, the travel speed of the spraying equipment, and the wear of the nozzle may affect the actual spraying volume, real-time monitoring is required during the spraying process. Flow monitoring sensors can be installed on the spraying equipment, or the actual spraying volume can be monitored by regularly measuring the thickness of the drag reducer in the sprayed area. If the spraying volume deviates from the target value, it should be corrected in time by adjusting the travel speed, spraying pressure or flow control device of the spraying equipment. For example, if the spraying volume is too much, the travel speed of the equipment can be appropriately increased or the spraying pressure can be reduced; conversely, if the spraying volume is insufficient, the travel speed should be reduced or the spraying pressure should be increased.

[0082] The friction reducing agent construction area is subjected to rotary tillage and mixing, and then the undiluted environmentally friendly friction reducing agent is injected again into the soil layer after rotary tillage and mixing according to the hole injection method. Specifically, the rotary tillage and mixing operation is performed using 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 0.5-1.0 m / s, and the rotary blade speed of the rotary tiller is 200-300 rpm.

[0083] After the injection and spraying of the environmentally friendly drag reducing agent is completed, the soil in the entire drag reducing agent construction area is deep plowed. Specifically, the deep plowing operation is carried out using 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.

[0084] After deep plowing is completed, the soil is compacted by layered compaction with a compaction degree of 90-95%. Specifically, multiple small compactors are first used to compact the deep soil (1.0-1.5 meters) for 3-5 times. The compactors operate at a certain interval (such as 1.0-1.5 meters) and in sequence to ensure that the deep soil is fully compacted. During the compaction process, attention should be paid to the compaction energy and frequency of the compactor. Generally, the compaction energy is controlled at 10-20 kJ and the frequency is 10-15 times / min to avoid excessive compaction that may cause soil compaction or damage to the resistance reducing agent structure. Then, the soil is gradually moved upwards, and the middle layer (0.5-1.0 meters) and surface layer (0-0.5 meters) are compacted 5-8 times and 8-10 times respectively, so that the soil compaction degree reaches 90%-95%. After each layer is compacted, use a compaction tester to test the soil compaction. If any area is found where the compaction does not meet the requirements, additional compaction should be carried out in time to ensure that the resistance reducer is tightly combined with the soil to form a stable resistance reduction structure. At the same time, the mechanical properties of the soil are improved to prevent the resistance reduction effect from being affected by soil settlement and deformation.

[0085] After the 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 real-time monitoring data of the soil moisture sensor and the preset humidity range, realizing intelligent moisture management and maintaining soil moisture between 20%-30% for 2-3 weeks, providing a suitable growth environment for the microbial flora in the resistance reducer, promoting its reproduction and metabolic activities, and further optimizing the soil structure and conductivity. During the maintenance period, the resistivity of the soil is measured every 3-5 days, using a high-precision soil resistivity tester to perform multi-point measurements at different locations and depths. According to the monitoring data, if it is found that the resistivity drop is not obvious or does not reach the expected target, timely problem analysis is carried out to find out the possible causes of the problem, such as uneven mixing of the resistance reducer and the soil, insufficient activity of the microbial flora, inappropriate moisture content and other factors. Take appropriate remedial measures for specific problems. If it is found that the resistance reducing agent is not evenly mixed with the soil, deep plowing equipment can be arranged to plow and stir the soil again. The plowing depth and method can be adjusted according to the actual situation. If the microbial flora is not active enough, a special microbial nutrient can be added in an appropriate amount to activate the flora. The type and dosage of the nutrient are selected and calculated according to the type of microbial flora and soil environmental conditions. If it is a moisture content problem, the irrigation system is used to accurately adjust the moisture, increase or decrease the irrigation water volume and irrigation frequency, and ensure that the soil moisture remains within an appropriate range to ensure that the resistance reducing agent can give full play to its performance and achieve the expected resistance reducing effect. Within a period of time after the resistance reducing project is put into use (such as half a year to one year), continue to regularly monitor the soil resistivity and conduct regular inspections of the resistance reducing agent. Conduct an appearance inspection of the resistance reduction area, measure the soil resistivity at certain time intervals (such as monthly or quarterly), observe the changing trend of the resistivity, and evaluate the long-term effectiveness and stability of the resistance reduction agent. At the same time, conduct regular appearance inspections of the resistance reduction area to observe whether there are abnormal conditions such as ground subsidence and cracks. If there are any abnormalities, analyze and deal with them in a timely manner to ensure the safety and reliability of the resistance reduction project. In addition, observe and record the growth of vegetation around the resistance reduction area, including vegetation type, coverage rate, growth height and other indicators. Since some components in the resistance reduction agent (such as phosphogypsum, complex microbial flora, etc.) may have a positive effect on soil fertility and microbial environment, thereby promoting vegetation growth, the monitoring of vegetation can indirectly reflect the improvement effect of the resistance reduction agent on the soil ecological environment.

[0086] The technical solution of the present invention is further described below through multiple embodiments and comparative examples:

[0087] Embodiment 1:

[0088] Environmentally friendly drag reducing agents include:

[0089] 15 parts of nano-graphene, 8 parts of nano-barium titanate, 5 parts of metal organic framework materials, 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 dodecylbenzene sulfonate (surfactant), 2 parts of disodium ethylenediaminetetraacetate (activating aid) and 20 parts of water, where 1 part of the above corresponds to 10 grams.

[0090] The preparation method of the environmentally friendly drag reducing agent comprises:

[0091] S1: Pretreatment of graphene nanosheets: Add graphene nanosheets to a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, stir and react at 60°C for 2 hours to perform oxidation treatment; wash the oxidized graphene nanosheets repeatedly with deionized water until neutral, then add them to a hydrazine hydrate solution and perform reduction reaction at 80°C for 1 hour; Pretreatment of barium titanate nanoparticles: Prepare tetrabutyl titanate ethanol solution and barium acetate ethanol solution respectively; Slowly stir the tetrabutyl titanate ethanol solution at 800 rpm. Add dropwise to the barium acetate ethanol solution, add glacial acetic acid as a catalyst, control the pH value of the solution at 3, continue stirring for 1 hour after the addition is completed, and form a uniform sol; transfer the sol to a high-pressure reactor and perform a hydrothermal reaction at 150°C for 12 hours; after the reaction is completed, cool naturally to room temperature, and obtain barium titanate nanoparticles by centrifugal separation, washing, and drying; pretreatment of metal organic framework materials: use copper nitrate and terephthalic acid as raw materials, dissolve copper nitrate in N,N-dimethylformamide with a volume ratio of 1:1 Acetic acid was added to a mixed solution of 1,2-dimethylformamide and ethanol to adjust the acidity of the solution; terephthalic acid was added to the above solution and ultrasonically dispersed for 30 minutes; the solution was transferred to a polytetrafluoroethylene-lined reactor and subjected to a solvent thermal reaction at 120°C for 24 hours; after the reaction, the solution was cooled to room temperature, centrifuged, repeatedly washed with N,N-dimethylformamide and ethanol, and finally dried 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: Dissolving polyvinyl butyral in water, heating to 80°C, and stirring until completely dissolved to obtain a polyvinyl butyral solution; slowly adding sodium alginate to the polyvinyl butyral solution, continuing to stir for 30 minutes, then adding a cross-linking agent, controlling the amount of the cross-linking agent to be 1% of the mass of the sodium alginate, reacting at 50°C for 1 hour to form a polyvinyl butyral-sodium alginate composite hydrogel; repeatedly washing the prepared polyvinyl butyral-sodium alginate composite hydrogel with deionized water, then drying at 40°C, and then crushing;

[0092] S2: 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 dodecylbenzene sulfonate and disodium ethylenediaminetetraacetic acid are added to the ball mill jar in sequence, and water and grinding balls are added, wherein the ball-to-material ratio is 3:1, the speed of the ball mill is 300 rpm, and the ball milling time is 4 hours.

[0093] S3: The ball-milled mixture was transferred to a reactor and stirred at 50° C. for 2 hours.

[0094] 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.

[0095] Embodiment 2:

[0096] Environmentally friendly drag reducing agents include:

[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 dodecylbenzene sulfonate (surfactant), 2.5 parts of disodium ethylenediaminetetraacetate (activating aid) and 25 parts of water, where 1 part of the above corresponds to 10 grams.

[0098] The preparation method of the environmentally friendly drag reducing agent comprises:

[0099] S1: Pretreatment of graphene nanosheets: Add graphene nanosheets to a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, stir and react at 70°C for 2.5 hours to perform oxidation treatment; wash the oxidized graphene nanosheets repeatedly with deionized water until neutral, then add them to a hydrazine hydrate solution and perform 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; Slowly stir the tetrabutyl titanate ethanol solution at 900 rpm. The mixture was added dropwise to a barium acetate ethanol solution, and glacial acetic acid was added as a catalyst. The pH value of the solution was controlled at 3.5. After the addition was completed, stirring was continued for 1.5 hours to form a uniform sol. The sol was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 180°C for 18 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, and barium titanate nanoparticles were obtained by centrifugal separation, washing, and drying. Pretreatment of metal organic framework materials: copper nitrate and terephthalic acid were used as the basic raw materials. The copper nitrate was dissolved in N,N-dimethylbenzene in a volume ratio of 1:1. Acetic acid was added to the mixed solution of formamide and ethanol to adjust the acidity of the solution; terephthalic acid was added to the above solution and ultrasonically dispersed for 45 minutes; the solution was transferred to a polytetrafluoroethylene-lined reactor and subjected to a solvent thermal reaction at 135°C for 36 hours; after the reaction, the solution was cooled to room temperature, centrifuged, repeatedly washed with N,N-dimethylformamide and ethanol, and finally dried in a vacuum drying oven at 90°C for 18 hours to obtain blue metal organic framework crystals; pretreatment of polyvinyl butyral-sodium alginate composite hydrogel: The method comprises the following steps: dissolving polyvinyl butyral in water, heating the solution to 85°C, and stirring the solution until the solution is completely dissolved to obtain a polyvinyl butyral solution; slowly adding sodium alginate into the polyvinyl butyral solution, continuing stirring for 45 minutes, and then adding a cross-linking agent, controlling the amount of the cross-linking agent to be 1.5% of the mass of the sodium alginate, and reacting the solution at 55°C for 1.5 hours to form a polyvinyl butyral-sodium alginate composite hydrogel; repeatedly washing the prepared polyvinyl butyral-sodium alginate composite hydrogel with deionized water, and then drying the solution at 45°C and then crushing the resultant.

[0100] S2: 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 dodecylbenzene sulfonate and disodium ethylenediaminetetraacetic acid are added into the ball mill jar in sequence, with a ball-to-material ratio of 3:1, a ball mill speed of 400 rpm, and a ball milling time of 5 hours.

[0101] S3: The ball-milled mixture was transferred to a reactor and stirred at 55° C. for 2.5 hours.

[0102] 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.

[0103] Embodiment 3:

[0104] The environmentally friendly drag reducing agent formula includes:

[0105] 20 parts of nano-graphene, 12 parts of nano-barium titanate, 8 parts of metal organic framework materials, 15 parts of polyvinyl butyral-sodium alginate composite hydrogel, 8 parts of polyaspartic acid, 12 parts of phosphogypsum, 6 parts of synthetic microbial flora, 12 parts of epoxy resin emulsion (binder), 5 parts of sodium carboxymethyl cellulose (stabilizer), 3 parts of sodium dodecylbenzene sulfonate (surfactant), 3 parts of disodium ethylenediaminetetraacetate (activating aid) and 30 parts of water, where 1 part of the above corresponds to 10 grams.

[0106] The preparation method of the environmentally friendly drag reducing agent comprises:

[0107] S1: Pretreatment of graphene nanosheets: Add graphene nanosheets to a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, stir and react at 80°C for 3 hours to perform oxidation treatment; Wash the oxidized graphene nanosheets repeatedly with deionized water until neutral, then add them to a hydrazine hydrate solution and perform 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 1000rpm, slowly add tetrabutyl titanate ethanol solution to barium acetate ethanol solution, and add glacial acetic acid as a catalyst to control the pH value of the solution at 4. After the addition is completed, continue stirring for 2 hours to form a uniform sol; Transfer the sol to a high-pressure reactor and perform hydrothermal reaction at 200°C for 24 hours; After the reaction is completed, naturally cool to room temperature, and obtain barium titanate nanoparticles by centrifugal separation, washing and drying; Pretreatment of metal organic framework materials: Use copper nitrate and terephthalic acid as The raw materials are: 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; terephthalic acid is added to the above solution, and ultrasonic dispersion is performed for 60 minutes; the solution is transferred to a polytetrafluoroethylene-lined reactor, and a solvent thermal reaction is performed at 150°C for 48 hours; after the reaction is completed, it is cooled to room temperature, and centrifuged, N,N-dimethylformamide and ethanol are repeatedly used; pretreatment of polyvinyl butyral-sodium alginate composite hydrogel: polyvinyl butyral is dissolved in water, heated to 90°C, and stirred until completely dissolved to obtain a polyvinyl butyral solution; sodium alginate is slowly added to the polyvinyl butyral solution, and stirring is continued for 60 minutes, and then a cross-linking agent is added, and the amount of the cross-linking agent is controlled to be 2% of the mass of the sodium alginate, and the reaction is performed at 60°C for 2 hours to form a polyvinyl butyral-sodium alginate composite hydrogel; the prepared product is repeatedly washed with deionized water, and then dried at 50°C and then crushed.

[0108] S2: 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 dodecylbenzene sulfonate and disodium ethylenediaminetetraacetic acid are added into the ball mill jar in sequence, with a ball-to-material ratio of 3:1, a ball mill speed of 500 rpm, and a ball milling time of 6 hours.

[0109] S3: The ball-milled mixture was transferred to a reactor and stirred at 60° C. for 3 hours.

[0110] 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.

[0111] Comparative Example 1:

[0112] Drag reducers include:

[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 lignin sulfonate and 40 parts of water, 1 part of the above corresponds to 10 grams.

[0114] The preparation method of the drag reducing agent comprises:

[0115] First, the coarse graphite particles are pretreated by placing them in a muffle furnace and calcining them at 650°C for 2.5 hours to remove surface impurities and activate the graphite structure to improve the conductivity. After being taken out and cooled, they are ball milled at 250 rpm for 1.5 hours to refine the particles to 20-30 meshes, and sieved for later use. Saturated aqueous solutions of potassium chloride, ferrous sulfate, and potassium dichromate are prepared respectively, and stirred at 450 rpm for 40 minutes at 55°C using a magnetic stirrer to fully dissolve them. Then the three solutions are mixed and stirred for 18 minutes. Calcium lignin sulfonate is slowly added to the above mixed solution, and stirred at 350rpm for 25 minutes to ensure uniform dispersion. Then cement is added and stirred for 45 minutes until a uniform slurry is formed. Finally, the pretreated graphite particles are added to the slurry and stirred at 300rpm for 1.5 hours to uniformly disperse the graphite particles in the system to obtain a finished drag reducing agent. The temperature, time and stirring speed must be strictly controlled during the entire preparation process, and the operating environment must be equipped with ventilation facilities to discharge harmful gases (such as a small amount of chromic acid mist produced by the volatilization of potassium dichromate).

[0116] Comparative Example 2:

[0117] Drag reducers include:

[0118] 12 parts of zinc powder, 8 parts of red lead, 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, 1 part of the above corresponds to 10 grams.

[0119] The preparation method of the drag reducing agent comprises:

[0120] Zinc powder and red lead were put into a ball mill, and an appropriate amount of anhydrous ethanol (the total mass ratio of ethanol to metal powder was 1:2) was added as a grinding aid, and the ball-to-material ratio was 2:1. The ball mill was milled at a speed of 350 rpm for 2.5 hours to fully mix the two and refine the particles. After ball milling, the ball mill was dried in a vacuum drying oven at 65°C for 5 hours to remove the ethanol. The coke powder was dry distilled at 450°C for 1.5 hours to remove volatiles and improve purity and stability. After cooling, the coke powder was sieved through a 35-mesh sieve for later use. An aqueous solution of sodium nitrite was prepared with a concentration of 35%. The solution was cleaned with an ultrasonic cleaner at 45°C. Ultrasonic treatment was performed for 25 minutes to accelerate dissolution; bentonite was slowly added to the glass solution in water, and stirred at 550 rpm with an electric stirrer for 40 minutes at 55°C until a uniform colloid was formed; the treated zinc powder-red lead mixture, coke powder, and sodium nitrite solution were sequentially added to the bentonite-water glass colloid, and each time an ingredient was added, it was stirred at 450 rpm for 25 minutes to ensure uniform mixing to obtain a resistance reducing agent slurry; the entire preparation process must be carried out in a fume hood to avoid inhalation of heavy metal dust such as lead and zinc and volatile gas of sodium nitrite.

[0121] The above-mentioned embodiments 1-3 and comparative examples 1 and 2 are constructed in the drag reducing agent construction area using the application method of the present invention. Each embodiment and each comparative example adopts a multi-point measurement method, that is, resistance is measured at different soil points and different depths in the drag reducing agent construction area. The soil resistance of embodiments 1-3 is 4-10Ω, the soil resistance of comparative example 1 is 28-53Ω, and the soil resistance of comparative example 2 is 33-67Ω. It can be seen that the drag reducing agent provided by the present invention is not only environmentally friendly, but also has an obvious drag reducing effect on the soil, and the deviation range of different positions is also small, and the stability is strong. Moreover, the water retention rate of the drag reducing agent of embodiments 1-3 and comparative examples 1 and 2 is measured. The 24-hour water retention rate of embodiments 1-3 can reach more than 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 drag reducing agent of the present invention has excellent water retention capacity.

[0122] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of further restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0123] Each embodiment of the present invention is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and 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, and the relevant parts can be referred to the partial description of the method embodiment.

[0124] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure is limited to these examples. Based on the concept of the present disclosure, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0125] While the disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0126] One or more embodiments of the present invention are intended to cover all such replacements, modifications and variations that fall within the scope of protection of the present invention. Therefore, any omissions, modifications, equivalent replacements, improvements, etc. made within the spirit and principles of one or more embodiments of the present invention should be included in the scope of protection of this disclosure.

Claims

1. An environmentally friendly drag reducing agent suitable for sandy wasteland geological 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.

2. The environmentally friendly drag reducing agent suitable for Shagohuang geological soil according to claim 1 is characterized in that: The binder is epoxy resin emulsion, and the stabilizer is sodium carboxymethyl cellulose.

3. The environmentally friendly drag reducing agent suitable for Shagohuang geological soil according to claim 1 is characterized in that: The surfactant is sodium dodecylbenzene sulfonate, and the activating aid is disodium ethylenediaminetetraacetate.

4. A method for preparing an environmentally friendly drag reducing agent suitable for sandy wasteland geological soil as claimed in any one of claims 1 to 3, 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 dodecylbenzene sulfonate, and disodium ethylenediaminetetraacetate to the ball mill of the ball mill in sequence, adding water and grinding balls, wherein 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; S3: transferring the ball-milled mixture into a reactor and continuing to stir and react 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.

5. The method for preparing an environmentally friendly drag reducing agent suitable for sandy soil according to claim 4, characterized in that: In step S1, the pretreatment of the graphene nanosheets includes: The graphene nanosheets are 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 they are neutral, and then added into a hydrazine hydrate solution for reduction reaction at 80-100° C. for 1-2 hours.

6. The method for preparing an environmentally friendly drag reducing agent suitable for sandy soil according to claim 4, characterized in that: In step S1, the pretreatment of barium titanate nanoparticles includes: Prepare tetrabutyl titanate ethanol solution and barium acetate ethanol solution respectively; Under vigorous stirring at 800-1000 rpm, the tetrabutyl titanate ethanol solution is slowly added dropwise to the barium acetate ethanol solution, and glacial acetic acid is added as a catalyst, and the pH value of the solution is controlled between 3-4. After the addition is completed, stirring is continued for 1-2 hours to form a uniform sol; The sol is transferred to a high pressure reactor and subjected to 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.

7. The method for preparing an environmentally friendly drag reducing agent suitable for sandy soil according to claim 4, characterized in that: In step S1, the pretreatment of the metal organic framework material includes: Using copper nitrate and terephthalic acid as raw materials, dissolving copper nitrate in a mixed solution of N,N-dimethylformamide and ethanol in a volume ratio of 1:1, and adding acetic acid to adjust the acidity of the solution; Add terephthalic acid to the above solution and disperse by ultrasonic 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.

8. The method for preparing an environmentally friendly drag reducing agent suitable for sandy soil according to claim 4, 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 crosslinking agent, control the amount of the crosslinking agent to be 1-2% of the mass of the sodium alginate, 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.

9. An application of an environmentally friendly drag reducing agent suitable for Shagohuang geological soil as claimed in any one of claims 1 to 3, characterized in that: The applications include: Determine the soil resistance reducer construction area, drill holes at a spacing of 0.5-1 meters in the resistance reducer construction area to form a grid-like hole network, where 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 a pipeline delivery system at a pressure of 0.5-1.0MPa and an injection speed of 1-2L / min; The diluted environmentally friendly drag reducing agent is sprayed in layers on the drag reducing agent construction area in a crisscross manner, wherein the spraying amount is 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 again into the soil layer after rotary tillage and stirring according to the hole injection method; After the injection and spraying of the environmentally friendly drag reducing agent is completed, the soil in the entire drag reducing agent construction area is deeply plowed; After deep tillage is completed, the soil is compacted by layering method with a compaction degree of 90-95%.

10. The use of the environmentally friendly drag reducing agent suitable for Shagohuang geological soil according to claim 9, characterized in that: The rotary tillage and mixing operation is performed 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 0.5-1.0 m / s, and the rotary blade speed of the rotary tiller is 200-300 rpm; 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.

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