Ecological sand solidification agent and preparation method thereof

Abstract

The invention discloses an ecological sand solidification agent and a preparation method thereof, and belongs to the technical field of crossing of ecological management and new energy. A three-dimensional network ecological sand fixing agent is constructed through in-situ polymerization-coordination synergistic reaction, the sand fixing agent forms an organic polymer-inorganic matter hybrid structure among sand grains, so that unification of high strength, high permeability and ecological friendliness is achieved, a sand fixing layer formed by the sand fixing agent and a sand land has excellent water permeability and air permeability, and the sand fixing agent has a good application prospect. The permeability coefficient can reach 5 * 10 <-3 > cm / s or above, it is guaranteed that rainfall can effectively infiltrate downwards to supply underground water due to the characteristic, moisture-air exchange in soil is maintained, a breathing channel is provided for microbial activity and penetration and growth of plant roots, and excellent ecological friendliness is achieved.

Description

Technical Field

[0001] This invention relates to the field of interdisciplinary technology of ecological governance and new energy, specifically to an ecological sand-fixing agent and its preparation method. Background Technology

[0002] The long-term stable operation of desert photovoltaic power stations faces severe challenges from wind and sand environments. On the one hand, wind erosion and migration of shifting sand threaten the stability of the photovoltaic array foundations; on the other hand, dust pollution severely reduces the power generation efficiency of photovoltaic modules, especially for bifacial photovoltaic modules that rely on surface reflection light gain, where stable surface albedo is crucial. Therefore, ideal sand fixation technology must simultaneously meet the requirements of high mechanical strength, excellent ecological permeability and aeration, and optical properties similar to native sandy land. However, existing chemical sand fixation technologies struggle to balance these conflicting needs. For example, while inorganic cementing materials such as cement and silicates have high strength, they form completely impermeable rigid slabs, altering soil pH and significantly affecting albedo. More widely used organic polymer materials such as polyvinyl alcohol (PVA) and polyacrylamide (PAM) mainly rely on non-bonding interactions such as physical entanglement and hydrogen bonding between polymer chains to achieve sand fixation. This physical cross-linking network has fundamental defects: 1) Poor weather resistance: Under strong ultraviolet radiation, huge temperature differences and wet-dry cycles in desert areas, physical cross-linking points are easily destroyed, causing the sand-fixing layer to age, crack and fail in a short period of time; 2) Structural-functional contradiction: In order to pursue high strength, the amount used is increased, which often forms a dense polymer film between sand grains, blocking soil pores and seriously sacrificing the water permeability and aeration necessary for the ecosystem; 3) Poor compatibility: Some materials or their by-products may have a negative impact on soil and vegetation, or reduce the light reflection of bifacial modules due to excessively dark color, thereby affecting power generation efficiency. Summary of the Invention

[0003] The main objective of this invention is to propose an ecological sand-fixing agent and its preparation method. The ecological sand-fixing agent constructs a three-dimensional network through in-situ polymerization-coordination synergistic reaction. This sand-fixing agent forms an "organic polymer-inorganic" hybrid structure between sand particles, thereby achieving a unity of high strength, high permeability and eco-friendliness.

[0004] The technical solution of this invention is implemented as follows: In a first aspect, the present invention proposes a method for preparing an ecological sand-fixing agent, comprising the following steps: S1. Add polymerizable polysaccharide to water to swell, then add acrylamide monomer and crosslinking agent, and stir until acrylamide and crosslinking agent are completely dissolved to obtain component A; S2. Dissolve the soluble metal salt and ammonium persulfate in water and stir until completely dissolved to obtain component B; S3. Mix KH-560, plant fiber, and water-retaining agent evenly to obtain component C; S4. After mixing component A and component C evenly, add component B and mix to obtain the ecological sand-fixing agent.

[0005] Preferably, in step S1, the mass ratio of polymerizable polysaccharide, acrylamide monomer, and crosslinking agent is 2-5:5-10:0.05-0.2.

[0006] More preferably, the polymerizable polysaccharide is methacrylated carboxymethyl cellulose; and the crosslinking agent is N,N'-methylenebisacrylamide.

[0007] Preferably, the mass ratio of the soluble metal salt to ammonium persulfate in step S2 is 1-3:0.1-0.3; more preferably, the soluble metal salt is calcium lactate.

[0008] Preferably, in step S3, the mass ratio of KH-560, plant fiber, and water-retaining agent is 0.5-1.5:1-3:0.1-0.5; the plant fiber is at least one of sisal fiber, jute fiber, wood fiber, flax fiber, cotton fiber, and coconut shell fiber; the water-retaining agent is an inorganic water-retaining agent and / or an organic water-retaining agent; the inorganic water-retaining agent is at least one of calcium chloride, sodium silicate, sodium chloride, magnesium sulfate, vermiculite, sepiolite, diatomaceous earth, fly ash, and palygorskite; and the organic water-retaining agent is at least one of polyacrylamide and ammonium polyacrylate.

[0009] Preferably, in step S4, the volume ratio of component A to component C is 4-6:1.

[0010] Secondly, the present invention also discloses an ecological sand-fixing agent prepared by the above-mentioned method for preparing ecological sand-fixing agents.

[0011] Thirdly, the present invention also discloses the application of the above-mentioned ecological sand-fixing agent, specifically as follows: Component A and Component C are mixed evenly in tank a of the spraying truck to obtain a mixed liquid; Component B is placed in tank b of the spraying truck; after the two liquid streams of the mixed liquid and Component B are evenly mixed by the static mixer on the spraying truck, they are sprayed onto the sandy surface.

[0012] Preferably, the spraying rate is 1-1.5 L / cm². 2 .

[0013] This invention constructs a three-dimensional network ecological sand-fixing agent through in-situ polymerization-coordination synergistic reaction. Under the action of sulfate free radicals generated by the decomposition of ammonium persulfate initiator, acrylamide monomer undergoes a free radical copolymerization reaction with the carbon-carbon double bonds on methacrylated carboxymethyl cellulose. Simultaneously, N,N'-methylenebisacrylamide, a crosslinking agent with a diene structure, participates in the reaction, connecting different polymer chains to form a stable, covalently-based first-order polymer crosslinking network. This polymer crosslinking network is the basis of the sand-fixing agent's strength. During the above polymerization reaction, calcium lactate in solution B dissociates into a large number of calcium ions. These divalent cations coordinate with the carboxyl and amide groups on the first-order polymer crosslinking network, forming a second-order crosslinking point with an egg-box structure. This endows the entire system with excellent toughness and a certain degree of self-healing ability. The egg-box structure is as follows:

[0014] The silane coupling agent KH-560 in the mixture acts as an interfacial adhesive. Its hydrolyzed group at one end undergoes dehydration condensation with the hydroxyl groups on the surface of sand particles (mainly SiO2) to form strong Si-O-Si chemical bonds. This greatly enhances the interfacial bonding force between the organic polymer and the inorganic sand particles. In this way, the formed double-network polymer is no longer simply physically filling the spaces between sand particles, but is chemically anchored to the surface of the sand particles, significantly improving its resistance to water erosion and wind erosion. The plant fibers dispersed in the system act as reinforcing fibers, effectively inhibiting shrinkage and microcrack formation during the solidification process, and improving the overall toughness and impact resistance of the sand-fixing layer. The water-retaining agent locks in moisture, providing a medium for chemical reactions on the one hand, and absorbing and retaining rainwater after solidification on the other hand, creating favorable conditions for potential plant growth.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention provides an ecological sand-fixing agent and its preparation method, which abandons the traditional sand-fixing agent's reliance on physical entanglement mode and constructs a dual-network hybrid structure between sand grains, which is composed of covalent bonds and ionic coordination bonds working together. Through the free radical copolymerization of acrylamide and methacrylated carboxymethyl cellulose and the chemical bridging of crosslinking agents, a stable covalent bond skeleton is formed, which is the basis for the high strength and high stability of the sand-fixing layer, giving it excellent compressive and shear resistance on a macroscopic scale. Then, the coordination of calcium ions with carboxyl and amide groups on the polymer chain forms dynamic and reversible ionic bond crosslinking points. This network not only further enhances the overall strength of the system, but also gives the sand-fixing layer unique toughness. When subjected to external impact, the ionic bonds can be partially broken and recombined, effectively dissipating energy and avoiding the brittle fracture that may occur in a pure covalent bond network. This dual-network structure, which combines rigidity and flexibility, has a wind erosion resistance and physical wear resistance far exceeding that of traditional sand-fixing agents that rely solely on physical mixing or single crosslinking methods. (2) This invention achieves a balance between sand-fixing strength and ecological permeability through multi-scale pore construction. The polymer network itself naturally forms nano- to micro-scale micropores during the cross-linking process. The plant fibers added to the system act as a sacrificial / functional template, occupying a certain physical space in the polymer network and forming larger-scale mesoscopic and macroscopic channels. This multi-level pore structure from nanoscale to macroscopic ensures that the sand-fixing layer has excellent water permeability and air permeability, with a permeability coefficient of up to 5×10⁻⁶. -3 With a speed of over cm / s, this characteristic ensures that rainfall can effectively infiltrate to replenish groundwater, maintain the water-air exchange inside the soil, and provide a breathing channel for microbial activity and the penetration and growth of plant roots, thus exhibiting excellent eco-friendliness. (3) The cured product of the present invention is a colorless to light yellow transparent gel encapsulating natural sand particles, which preserves the original optical appearance of the sand to the greatest extent. According to the test, the albedo of the ground surface after curing (especially in the visible light-near infrared band that bifacial photovoltaic modules are sensitive to) changes by less than 5%, which has little impact on the back power generation gain of bifacial modules and solves many of the pain points of traditional sand fixation agents causing the ground surface color to darken and power generation to decrease. (4) This invention achieves superior interfacial bonding and weather resistance through chemical anchoring and in-situ construction. The silane coupling agent KH-560 acts as a molecular bridge, and the silanol (-Si-OH) generated by hydrolysis at one end can undergo dehydration condensation reaction with the hydroxyl groups on the surface of sand particles to form strong Si-O-Si covalent bonds. This makes the organic polymer network no longer a simple physical coating, but is firmly chemically anchored to the surface of sand particles. This strong interfacial bonding is the key to the sand-fixing layer's ability to resist repeated thermal expansion and contraction caused by the huge diurnal temperature difference in desert areas, as well as the damage caused by dry-wet and freeze-thaw cycles, thus ensuring its long service life and weather resistance. At the same time, this invention adopts an in-situ polymerization construction method of two-component on-site mixing and immediate spraying, which allows the low-viscosity liquid reactants to fully penetrate into the sand layer to the predetermined depth by gravity and capillary action, achieving overall solidification from the inside out, rather than just forming a fragile outer crust. This solidification mode further enhances the integrity and wind erosion resistance of the sand-fixing layer. Detailed Implementation

[0016] To avoid unnecessary details, unless otherwise specified, all items used in the following examples are commercially available products, and all methods used are conventional methods unless otherwise specified.

[0017] Methacrylated carboxymethyl cellulose was purchased from Aladdin Biochemical Technology Co., Ltd.

[0018] Traditional asphalt-based sand stabilizing agent is a dark brown, homogeneous liquid with a solid content of ≥45%, a density (25℃) of 1.05±0.05 g / cm³, a viscosity (25℃) of 80-150 mPa·s, and a pH value of 7.5-9.5.

[0019] Example 1

[0020] A method for preparing an ecological sand-fixing agent includes the following steps: S1. Add 3g of methacrylated carboxymethyl cellulose to 45g of ice water to swell for 1 hour. Then add 8g of acrylamide and 0.1g of N,N'-methylenebisacrylamide and stir at room temperature until the acrylamide and N,N'-methylenebisacrylamide are completely dissolved to obtain component A. S2. Dissolve 2g of calcium lactate and 0.2g of ammonium persulfate in 15g of water and stir at room temperature until completely dissolved to obtain component B; S3. Mix 1g KH-560, 2g flax fiber, and 0.3g diatomaceous earth evenly to obtain component C; S4. Mix component A and component C at a volume ratio of 5:1 until homogeneous, then add component B and mix until homogeneous to obtain the ecological sand-fixing agent.

[0021] Example 2

[0022] A method for preparing an ecological sand-fixing agent includes the following steps: S1. Add 2g of methacrylated carboxymethyl cellulose to 40g of ice water to swell for 1 hour. Then add 5g of acrylamide and 0.05g of N,N'-methylenebisacrylamide and stir at room temperature until the acrylamide and N,N'-methylenebisacrylamide are completely dissolved to obtain component A. S2. Dissolve 1g of calcium lactate and 0.1g of ammonium persulfate in 12g of water and stir at room temperature until completely dissolved to obtain component B; S3. Mix 0.5g KH-560, 1g flax fiber, and 0.1g diatomaceous earth evenly to obtain component C; S4. Mix component A and component C at a volume ratio of 4:1 until homogeneous, then add component B and mix until homogeneous to obtain the ecological sand-fixing agent.

[0023] Example 3

[0024] A method for preparing an ecological sand-fixing agent includes the following steps: S1. Add 5g of methacrylated carboxymethyl cellulose to 50g of ice water to swell for 1 hour. Then add 10g of acrylamide and 0.2g of N,N'-methylenebisacrylamide and stir at room temperature until the acrylamide and N,N'-methylenebisacrylamide are completely dissolved to obtain component A. S2. Dissolve 3g of calcium lactate and 0.3g of ammonium persulfate in 20g of water and stir at room temperature until completely dissolved to obtain component B; S3. Mix 1.5g KH-560, 3g flax fiber, and 0.5g diatomaceous earth evenly to obtain component C; S4. Mix component A and component C at a volume ratio of 6:1 until homogeneous, then add component B and mix until homogeneous to obtain the ecological sand-fixing agent.

[0025] Comparative Example 1 A method for preparing an ecological sand-fixing agent, similar to Example 1, except that calcium lactate is not added, specifically including the following steps: S1. Add 3g of methacrylated carboxymethyl cellulose to 45g of ice water to swell for 1 hour. Then add 8g of acrylamide and 0.1g of N,N'-methylenebisacrylamide and stir at room temperature until the acrylamide and N,N'-methylenebisacrylamide are completely dissolved to obtain component A. S2. Dissolve 0.2g of ammonium persulfate in 15g of water and stir at room temperature until completely dissolved to obtain component B; S3. Mix 1g KH-560, 2g flax fiber, and 0.3g diatomaceous earth evenly to obtain component C; S4. Mix component A and component C at a volume ratio of 5:1 until homogeneous, then add component B and mix until homogeneous to obtain the ecological sand-fixing agent.

[0026] Comparative Example 2 A method for preparing an ecological sand-fixing agent, similar to Example 1, except that N,N'-methylenebisacrylamide is not added, specifically including the following steps: S1. Add 3g of methacrylated carboxymethyl cellulose to 45g of ice water to swell for 1 hour, then add 8g of acrylamide and stir at room temperature until the acrylamide is completely dissolved to obtain component A. S2. Dissolve 2g of calcium lactate and 0.2g of ammonium persulfate in 15g of water and stir at room temperature until completely dissolved to obtain component B; S3. Mix 1g KH-560, 2g flax fiber, and 0.3g diatomaceous earth evenly to obtain component C; S4. Mix component A and component C at a volume ratio of 5:1 until homogeneous, then add component B and mix until homogeneous to obtain the ecological sand-fixing agent.

[0027] Comparative Example 3 A method for preparing an ecological sand-fixing agent, similar to Example 1, except that KH-560 is not added, specifically including the following steps: S1. Add 3g of methacrylated carboxymethyl cellulose to 45g of ice water to swell for 1 hour. Then add 8g of acrylamide and 0.1g of N,N'-methylenebisacrylamide and stir at room temperature until completely dissolved to obtain component A. S2. Dissolve 2g of calcium lactate and 0.2g of ammonium persulfate in 15g of water and stir at room temperature until completely dissolved to obtain component B; S3. Mix 2g of flax fiber and 0.3g of diatomaceous earth evenly to obtain component C; S4. Mix component A and component C at a volume ratio of 5:1 until homogeneous, then add component B and mix until homogeneous to obtain the ecological sand-fixing agent.

[0028] Comparative Example 4 A method for preparing an ecological sand-fixing agent is similar to that in Example 1, except that carboxymethyl cellulose is not alkenylated, specifically including the following steps: S1. Add 3g of carboxymethyl cellulose to 45g of ice water to swell for 1 hour. Then add 8g of acrylamide and 0.1g of N,N'-methylenebisacrylamide and stir at room temperature until the acrylamide and N,N'-methylenebisacrylamide are completely dissolved to obtain component A. S2. Dissolve 2g of calcium lactate and 0.2g of ammonium persulfate in 15g of water and stir at room temperature until completely dissolved to obtain component B; S3. Mix 1g KH-560, 2g flax fiber, and 0.3g diatomaceous earth evenly to obtain component C; S4. Mix component A and component C at a volume ratio of 5:1 until homogeneous, then add component B and mix until homogeneous to obtain the ecological sand-fixing agent.

[0029] Application examples To verify the beneficial effects of the ecological sand-fixing agent of the present invention, the sand-fixing agents prepared in Examples 1-3 were compared with the sand-fixing agents prepared in Comparative Examples 1-4 and traditional asphalt-based sand-fixing agents in terms of performance.

[0030] Referring to the formulations of Examples 1-3 and Comparative Examples 1-4, samples were prepared and sprayed on-site using a dual-tank sprinkler truck, as follows: Components A and C in each formulation were premixed in the sprinkler truck tank at the appropriate ratios to obtain a mixture. Then, the mixture was statically mixed with component B according to the volume ratios in Examples 1-3 and Comparative Examples 1-4, and then sprayed at 1.2 L / m³. 2The agent was sprayed onto the sandy ground, and a control group using traditional asphalt-based sand-fixing agents was set up. After the samples were completely cured for 48 hours, 10 points were randomly selected on the sample surface using a Shore C hardness tester, and the average value was taken. The vertical permeability coefficient of the cured sample (approximately 2 cm thick) was tested using the constant head method. The average reflectance of the cured sample in the 550-950 nm band (a key band for photovoltaic power generation) was measured using a portable spectrometer and compared with the background value of the untreated original sandy ground to calculate the rate of change (%). 100 grass seeds were evenly sown on the surface of the cured sample plot, and suitable temperature and humidity were maintained. After 28 days, the number of germinated grass seeds was counted, and the germination rate (%) was calculated. This step was used to evaluate the effect of the sand-fixing agent on plant growth. The test results are shown in Table 1. Table 1: Performance test results of the sand-fixing agent of the present invention and traditional asphalt-based sand-fixing agents

[0031] As can be seen from the experimental results in Table 1, the sand-fixing agent obtained in the embodiments of the present invention exhibits high surface hardness, extremely low reflectivity, and plant growth-friendly properties, and has characteristics such as high strength, optical compatibility, and eco-friendliness.

[0032] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A method for preparing an ecological sand-fixing agent, characterized in that, The method comprises the following steps: S1, adding a polymerizable polysaccharide into water for swelling, then adding acrylamide monomer and a crosslinking agent, stirring until the acrylamide and the crosslinking agent are completely dissolved to obtain an A component; S2, dissolving a soluble metal salt and ammonium persulfate in water, stirring until completely dissolved to obtain a B component; S3, mixing KH-560, plant fiber and water-retaining agent uniformly to obtain a C component; S4, mixing the A component and the C component uniformly, then adding the B component to mix to obtain an ecological sand fixation agent.

2. The method of claim 1, wherein: In the step S1, the mass ratio of the polymerizable polysaccharide, the acrylamide monomer and the crosslinking agent is 2-5:5-10:0.05-0.

2.

3. The method of claim 2, wherein: The polymerizable polysaccharide is methacrylated carboxymethyl cellulose; and the crosslinking agent is N,N'-methylene bisacrylamide.

4. The method of claim 1, wherein: In the step S2, the mass ratio of the soluble metal salt and ammonium persulfate is 1-3:0.1-0.

3.

5. The method of claim 4, wherein: The soluble metal salt is calcium lactate.

6. The method of claim 1, wherein: In the step S3, the mass ratio of KH-560, plant fiber and water-retaining agent is 0.5-1.5:1-3:0.1-0.

5.

7. The method of claim 1, wherein: In the step S4, the volume ratio of the A component and the C component is 4-6:

1.

8. An ecological sand stabilizer, characterized by: Prepared by the method of any one of claims 1-7.

9. Use of the ecological sand binder according to claim 8, characterized in that, The method comprises the following steps: mixing the A component and the C component in the a tank of a spraying vehicle to obtain a mixed solution; placing the B component in the b tank of the spraying vehicle; mixing the mixed solution and the B component through a static mixer on the spraying vehicle, then spraying the mixture onto the surface of the sand.

10. Use according to claim 9, characterized in that: The spraying amount is 1-1.5 L / m 2 .

Images