Degradable farmland wind prevention and sand fixation agent and preparation method thereof

Abstract

The invention provides a degradable farmland wind prevention and sand fixation agent and a preparation method thereof, and relates to the field of environmental governance materials. Comprising the following raw materials: 80-90% of deionized water, 2-8% of plant polysaccharide, 1-2% of microbial polysaccharide, 5-15% of organic high-molecular polymer and 0.1-0.5% of inorganic salt. The sand stabilizing agent has the advantages of excellent sand stabilizing effect, high permeability, no pollution to the environment, low cost and convenience in application and scattering.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental governance materials, in particular, relates to a kind of degradable farmland windbreak and sand-fixing agent and preparation method thereof. BACKGROUND

[0002] In China, drought, semi-arid and sub-humid arid regions, precipitation is less and evaporation is large, soil moisture is seriously insufficient, frequent gale weather accelerates the process of soil erosion, at the same time, due to the natural conditions such as topography and sandy soil, which provides the condition for wind erosion, leading to desertification of cultivated land is becoming more and more serious.

[0003] Desertification control usually realizes wind prevention, sand fixation and water conservation by means of forest protection, grass grid sand barrier, plant mixed planting, artificial water storage engineering, etc., but it cannot be widely promoted due to factors such as single type of vegetation, high cost, limited service life, etc. In recent years, chemical sand-fixing agent can react with sand particles due to its special chemical composition, form a strong network structure, effectively fix sand, and improve the wind erosion resistance of soil. However, as a new type of desertification control technology, the public awareness is low, the environmental degradability is poor, and it cannot be widely applied and promoted.

[0004] The main defects of the farmland sand-fixing agent on the market at present are as follows: difficult preparation process, poor permeability, insufficient crust strength, etc. The Chinese patent document with publication number CN 102127453 and publication date July 20, 2011 discloses a chemical sand-fixing agent and its preparation method, which is characterized by containing, by mass percentage, 40-60% of water glass with modulus of 2.8-3.3, 0.08-0.12% of sorbitol, 1.2-1.8% of lithium carbonate and 0.1% of polyacrylamide. The sand-fixing agent is prepared by reasonably compounding the water glass modified by chemical method with organic polymer materials, and the raw materials and process flow are appropriately selected, so that the sand-fixing agent has the characteristics of good sand-fixing effect, no pollution to environment, strong aging resistance, simple preparation, convenient construction, etc. However, the raw materials of the sand-fixing agent are petroleum raw materials, and the permeability of the sand-fixing agent is poor. SUMMARY

[0005] The present application provides a degradable farmland windbreak and sand-fixing agent, which has excellent sand-fixing effect, strong permeability, no pollution to environment, low cost and is convenient to spread.

[0006] Another object of the present application is to provide a preparation method of the degradable farmland windbreak and sand-fixing agent, which is simple and has low requirements on equipment.

[0007] The technical problem of the present application is solved by the following technical scheme.

[0008] On the one hand, embodiments of the present invention provide a biodegradable farmland windbreak and sand-fixing agent, which, by mass fraction, includes the following raw materials: 80-90% deionized water, 2-8% plant polysaccharides, 1-2% microbial polysaccharides, 5-15% organic polymers, and 0.1-0.5% inorganic salts.

[0009] In some embodiments of the present invention, the plant polysaccharide includes starch, and at least one of sodium alginate, cellulose, lignin, guar gum, and carrageenan; and the starch accounts for 60-80% of the total mass of the plant polysaccharide.

[0010] In some embodiments of the present invention, the microbial polysaccharide is xanthan gum.

[0011] In some embodiments of the present invention, the organic polymer is at least one of polyvinyl alcohol, redispersible latex powder, and polyacrylamide.

[0012] In some embodiments of the present invention, the inorganic salt is at least one of sodium chloride, calcium chloride, calcium phosphate, and ammonium phosphate.

[0013] On the other hand, embodiments of the present invention provide a method for preparing a biodegradable farmland windbreak and sand-fixing agent, comprising the following steps: S1: Inject deionized water and inorganic salt into the stirring tank in sequence, heat to 50-60℃, and completely dissolve to obtain a salt solution; S2: Maintain the system temperature, and add plant polysaccharides, organic polymers, and microbial polysaccharides to the salt solution in sequence, adding the next material after the previous material has dissolved. After the materials have dissolved, a mixture is obtained; cool to room temperature to obtain the sand-fixing agent.

[0014] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: The biodegradable farmland windbreak and sand-fixing agent provided by this invention comprises plant polysaccharides and microbial polysaccharides. After spraying and dehydration, it forms a flexible film layer on the sandy soil surface, creating a gradient structure with a dense surface layer and a loose underlying layer, allowing rainwater infiltration. The polar groups of the polysaccharide molecular chains form hydrogen bonds or ionic bonds with metal ions or silanol groups on the sandy soil surface, binding the loose sand into stable aggregates. Simultaneously, the porous network structure of the polysaccharides can absorb more than 10-20 times its own weight in water, delaying water evaporation from the sandy soil, increasing the water retention rate of the sandy soil, and providing a moist environment for plant growth. Furthermore, the degradation products of the polysaccharides, as carbon sources and nutrients, can stimulate microbial reproduction and plant root growth. The inorganic salts in the sand-fixing agent can compress the surfactant double layer, reduce the interfacial repulsion of ion heads, promote micelle formation, increase the number of micelle aggregates, enhance the encapsulation capacity of hydrophobic solutes, weaken the hydrophobic effect, and improve solubilization efficiency. Furthermore, the combination of low-concentration inorganic salts and organic polymers constructs new chemical bonds between sand particles, thereby achieving sand and soil solidification. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 The crust layer formed after spraying the sand-fixing agent of Example 1. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0019] A biodegradable farmland windbreak and sand-fixing agent, by mass fraction, comprises the following raw materials: 80-90% deionized water, 2-8% plant polysaccharides, 1-2% microbial polysaccharides, 5-15% organic polymer, and 0.1-0.5% inorganic salts.

[0020] The plant polysaccharides include starch, and at least one of sodium alginate, cellulose, lignin, guar gum, and carrageenan; and the starch accounts for 60-80% of the total mass of the plant polysaccharides. The plant polysaccharides, with starch as the main component, provide adhesive properties, forming a primary sand-fixing network. The remaining plant polysaccharides enhance viscosity, water retention, strength, and film-forming properties; for example, cellulose enhances mechanical strength, and sodium alginate improves film-forming properties and weather resistance.

[0021] The microbial polysaccharide is xanthan gum. Xanthan gum can significantly increase solution viscosity, enhance sand-fixing effect, has excellent pseudoplasticity, facilitates spraying and film formation, enhances the solubility and stability of other polysaccharides, has good salt tolerance, and is adaptable to different soil conditions.

[0022] The organic polymer is at least one of polyvinyl alcohol, redispersible latex powder, and polyacrylamide. Polyvinyl alcohol provides strong film-forming ability, enhances wind erosion resistance, and is biodegradable; redispersible latex powder improves flexibility and water resistance, and enhances adhesion to various sand particles; polyacrylamide has a flocculating effect, promotes sand particle aggregation, and improves water retention. The inorganic salt is at least one of sodium chloride, calcium chloride, calcium phosphate, and ammonium phosphate. Redispersible latex powder refers to substances such as copolymers of ethylene-vinyl acetate, vinyl acetate-ethylene tert-carbonate copolymers, and acrylic acid copolymers.

[0023] Sodium chloride / calcium chloride: Regulates the ionic strength of the solution, promotes cross-linking of polysaccharide molecules, and enhances the water resistance of the sand-fixing layer. Phosphate: Provides plants with available phosphorus, regulates the degradation rate, and buffers pH.

[0024] In summary, the sand-fixing agent provided in this invention uses biodegradable natural polysaccharides and organic polymers as raw materials, avoiding the environmental pollution problems of traditional chemical sand-fixing agents. Each component can be decomposed by microorganisms under natural conditions, preventing long-term soil pollution. The synergistic effect of polysaccharides and organic polymers forms a three-dimensional network structure, effectively fixing sand particles. Xanthan gum significantly improves the viscosity and water retention of the solution. The formula is pH neutral, not altering the soil's acid-base balance. It does not affect subsequent crop planting; some degradation products can even serve as plant nutrients. The water-based formula is easy to spray and has good permeability. Furthermore, the high proportion of plant polysaccharides reduces dependence on expensive synthetic materials, thus lowering raw material costs. Plant polysaccharides and organic polymers have a synergistic effect: plant polysaccharides provide basic viscosity, organic polymers enhance mechanical strength, and xanthan gum acts as a bridging molecule, promoting interactions between different polysaccharides and polymers to form a more stable three-dimensional network structure. When sprayed into the soil, this three-dimensional network structure forms on the soil surface and upper layer, causing sand and soil to aggregate into clumps.

[0025] Synergistic effect of inorganic salts and polysaccharides: Inorganic salts form free ions in water, which can neutralize the charge of polysaccharide molecules, promote the aggregation of polysaccharide molecular chains, and facilitate the formation of divalent cations (Ca). 2+ It forms ionic crosslinks with sodium alginate and other substances, enhancing the strength of the three-dimensional network structure.

[0026] Easily degradable components such as starch provide initial sand-fixing effects, while slower-degrading components such as polyvinyl alcohol provide long-term protection. Phosphate acts as a buffer, regulating the overall degradation rate.

[0027] The preparation method of the above-mentioned biodegradable farmland windbreak and sand-fixing agent includes the following steps: S1: Inject deionized water and inorganic salt into the stirring tank in sequence, heat to 50-60℃, and completely dissolve to obtain a salt solution; S2: Maintain the system temperature, and add plant polysaccharides, organic polymers, and microbial polysaccharides to the salt solution in sequence, adding the next material after the previous material has dissolved. After the materials have dissolved, a mixture is obtained; cool to room temperature to obtain the sand-fixing agent.

[0028] During the preparation process, inorganic salts are dissolved first to ensure a stable ionic environment. Then, different polysaccharides and polymers are added gradually. After the previous raw material is dissolved, another raw material is added to avoid excessively high local concentrations. The temperature of 50-60℃ promotes the full dissolution of each component without degradation.

[0029] The features and performance of the present invention will be further described in detail below with reference to embodiments. Example

[0030] The sand-fixing agent of this embodiment was prepared according to the following proportions and methods: 80% deionized water, 8% plant polysaccharides, 2% microbial polysaccharides (xanthan gum), 9.5% organic polymers, and 0.5% inorganic salts.

[0031] In this embodiment, the plant polysaccharide comprises 80% starch, 10% sodium alginate, and 10% cellulose.

[0032] The organic polymers are polyvinyl alcohol and polyacrylamide, with a mass ratio of 1:1. The inorganic salts are sodium chloride and calcium chloride, with a mass ratio of 1:1.

[0033] The preparation method of this sand-fixing agent includes the following steps: S1: Deionized water and inorganic salt are sequentially injected into a stainless steel jacketed mixing tank. The jacket is heated to 58°C to completely dissolve the salt solution. S2: Maintain the temperature of the system inside the mixing tank, and add plant polysaccharides, organic polymers, and xanthan gum to the salt solution in sequence, adding the next material only after the previous material has completely dissolved. After the materials have completely dissolved, a mixture is obtained; cool to room temperature to obtain the sand-fixing agent. Example

[0034] The sand-fixing agent of this embodiment was prepared according to the following proportions and methods: 85% deionized water, 2% plant polysaccharides, 1% microbial polysaccharides (xanthan gum), 11.9% organic polymers, and 0.1% inorganic salts.

[0035] In this embodiment, the plant polysaccharide comprises 80% starch, 10% sodium alginate, 5% cellulose, and 5% lignin.

[0036] The organic polymer is polyvinyl alcohol and redispersible latex powder, with a mass ratio of 1:1. The inorganic salts are sodium chloride and calcium chloride, with a mass ratio of 1:1.

[0037] The preparation method of this sand-fixing agent includes the following steps: S1: Deionized water and inorganic salt are sequentially injected into a stainless steel jacketed mixing tank. The jacket is heated to 58°C to completely dissolve the salt solution. S2: Maintain the temperature of the system inside the mixing tank, and add plant polysaccharides, organic polymers, and xanthan gum to the salt solution in sequence, adding the next material only after the previous material has completely dissolved. After the materials have completely dissolved, a mixture is obtained; cool to room temperature to obtain the sand-fixing agent. Example

[0038] The sand-fixing agent of this embodiment was prepared according to the following proportions and methods: Deionized water 81.7%, plant polysaccharides 2%, microbial polysaccharides (xanthan gum) 1%, organic polymers 15%, inorganic salts 0.3%.

[0039] In this embodiment, the plant polysaccharide comprises 80% starch, 10% cellulose, 5% guar gum, and 5% carrageenan.

[0040] The organic polymers are polyvinyl alcohol, polyacrylamide, and redispersible latex powder, with a mass ratio of 1:1:1. The inorganic salts are sodium chloride and calcium phosphate, with a mass ratio of 1:1.

[0041] The preparation method of this sand-fixing agent includes the following steps: S1: Deionized water and inorganic salt are sequentially injected into a stainless steel jacketed mixing tank. The jacket is heated to 58°C to completely dissolve the salt solution. S2: Maintain the temperature of the system inside the mixing tank, and add plant polysaccharides, organic polymers, and xanthan gum to the salt solution in sequence, adding the next material only after the previous material has completely dissolved. After the materials have completely dissolved, a mixture is obtained; cool to room temperature to obtain the sand-fixing agent. Example

[0042] The sand-fixing agent of this embodiment was prepared according to the following proportions and methods: 90% deionized water, 2% plant polysaccharides, 1% microbial polysaccharides (xanthan gum), 6.5% organic polymers, and 0.5% inorganic salts.

[0043] In this embodiment, the plant polysaccharide comprises 80% starch, 10% lignin, 4% guar gum, and 6% carrageenan.

[0044] The organic polymers are polyvinyl alcohol and polyacrylamide, with a mass ratio of 1:1. The inorganic salts are sodium chloride and calcium chloride, with a mass ratio of 1:1.

[0045] The preparation method of this sand-fixing agent includes the following steps: S1: Deionized water and inorganic salt are sequentially injected into a stainless steel jacketed mixing tank. The jacket is heated to 58°C to completely dissolve the salt solution. S2: Maintain the temperature of the system inside the mixing tank, and add plant polysaccharides, organic polymers, and xanthan gum to the salt solution in sequence, adding the next material only after the previous material has completely dissolved. After the materials have completely dissolved, a mixture is obtained; cool to room temperature to obtain the sand-fixing agent. Example

[0046] The sand-fixing agent of this embodiment was prepared according to the following proportions and methods: Deionized water 80.7%, plant polysaccharides 5.5%, microbial polysaccharides (xanthan gum) 1.5%, organic polymers 12%, inorganic salts 0.3%.

[0047] In this embodiment, the plant polysaccharide comprises 80% starch, 5% sodium alginate, 10% cellulose, and 5% guar gum.

[0048] The organic polymers are polyvinyl alcohol, polyacrylamide, and redispersible latex powder, with a mass ratio of 1:1:0.5. The inorganic salts are sodium chloride, calcium chloride, and ammonium phosphate, with a mass ratio of 1:1:0.5.

[0049] The preparation method of this sand-fixing agent includes the following steps: S1: Deionized water and inorganic salt are sequentially injected into a stainless steel jacketed mixing tank. The jacket is heated to 50°C to completely dissolve the salt solution. S2: Maintain the temperature of the system inside the mixing tank, and add plant polysaccharides, organic polymers, and xanthan gum to the salt solution in sequence, adding the next material only after the previous material has completely dissolved. After the materials have completely dissolved, a mixture is obtained; cool to room temperature to obtain the sand-fixing agent.

[0050] The difference from Example 1 is that xanthan gum is not added, but the remaining proportions and preparation methods are the same as in Example 1.

[0051] The difference from Example 1 is that no plant polysaccharides are added, but the remaining proportions and preparation methods are the same as in Example 1.

[0052] 1. Wind erosion resistance test Wind tunnel simulation test: In a controlled wind tunnel, the sand-fixing agents of Examples 1-5 and Comparative Examples 1-2 were sprayed onto a surface (20cm×20cm×5cm). After natural curing for 24 hours, the surface was treated for 60 minutes at wind speeds of 5m / s and 10m / s, respectively. The wind erosion rate (Q) was calculated. Where m0 and m tLet Q represent the mass (g) before and after the test, A represent the sample area (m²), and t represent the time (h). The acceptance criterion is: Q < 50 g / m²·h at a wind speed of 10 m / s. The results are shown in Table 1.

[0053] Table 1 Table 1 shows that after treatment with the sand-fixing agent in Examples 1-5, the wind erosion rates were less than 12 g / m²·h and 32 g / m²·h, respectively, which meet the standards for sand-fixing agents.

[0054] 2. Surface hardness test: The sand-fixing agents of Examples 1-5 and Comparative Examples 1-2 were sprayed on the surface (20cm×20cm×5cm). After natural curing, the surface hardness of the cured layer was measured using a Shore hardness tester (Type D). The results are shown in Table 2.

[0055] Table 2 As can be seen from Table 2, after the sand-fixing agents of Examples 1-5 are sprayed on the surface of sand and cured naturally, their hardness can reach 40 and 55 or higher, and their compressive strength can reach 1.2 MPa and 1.7 MPa or higher. The solidified layer has high strength and hardness and strong sand-fixing ability.

[0056] Appendix Figure 1 The image shows a crust layer formed on the surface of the sand layer after spraying the sand-fixing agent of Example 1. As can be seen from the figure, the crust layer has a certain thickness and can be picked up in chunks.

[0057] In summary, the sand-fixing agent provided in this embodiment of the invention, after spraying and dehydration, forms a flexible film layer on the surface of sand, creating a gradient structure with a dense surface layer and a loose underlying layer. This allows rainwater to infiltrate. The polar groups of the polysaccharide molecular chains form hydrogen bonds or ionic bonds with metal ions or silanol groups on the surface of the sand, binding the loose sand into stable aggregates. At the same time, the porous network structure of the polysaccharide can absorb more than 10-20 times its own weight in water, delaying water evaporation in the sand, increasing the water retention rate of the sand, and providing a moist environment for plant growth. In addition, the degradation products of the polysaccharide, as carbon sources and nutrients, can stimulate microbial reproduction and plant root growth.

[0058] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A biodegradable farmland windbreak and sand-fixing agent, characterized in that, By mass fraction, it includes the following raw materials: Deionized water 80-90%, plant polysaccharides 2-8%, microbial polysaccharides 1-2%, organic polymers 5-15%, inorganic salts 0.1-0.5%.

2. The biodegradable farmland windbreak and sand-fixing agent according to claim 1, characterized in that, The plant polysaccharide includes starch, and at least one of sodium alginate, cellulose, lignin, guar gum, and carrageenan; and the starch accounts for 60-80% of the total mass of the plant polysaccharide.

3. The biodegradable farmland windbreak and sand-fixing agent according to claim 1, characterized in that, The microbial polysaccharide is xanthan gum.

4. The biodegradable farmland windbreak and sand-fixing agent according to claim 1, characterized in that, The organic polymer is at least one of polyvinyl alcohol, redispersible latex powder, and polyacrylamide.

5. The biodegradable farmland windbreak and sand-fixing agent according to claim 1, characterized in that, The inorganic salt is at least one of sodium chloride, calcium chloride, calcium phosphate, and ammonium phosphate.

6. A method for preparing a biodegradable farmland windbreak and sand-fixing agent as described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Inject deionized water and inorganic salt into the stirring tank in sequence, heat to 50-60℃, and completely dissolve to obtain a salt solution; S2: Maintain the system temperature, and add plant polysaccharides, organic polymers, and microbial polysaccharides to the salt solution in sequence, adding the next material after the previous material has dissolved. After the materials have dissolved, a mixture is obtained; cool to room temperature to obtain the sand-fixing agent.

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