Dust suppressant, preparation method and application

Abstract

The invention relates to the technical field of environmental pollution treatment and particularly provides a dust suppressant as well as a preparation method and application thereof. In order to achieve the purpose, the dust suppressant provided by the invention is prepared from the following raw material components: sodium lignin sulfonate extracted based on lotus stems, deionized water, a first cross-linking agent, a second cross-linking agent, an aqueous solution of organic acid, a first initiator and a second initiator. Wherein the sodium lignin sulfonate is extracted from lotus stems. Through a specific molecular modification technology, sodium lignin sulfonate is extracted and prepared from lotus stems, and the novel dust suppressant applied to roads is prepared through graft copolymerization. The dust suppressant has multiple properties, the structure of the dust suppressant is beneficial to suppression of a dust resuspension phenomenon, and the dust suppressant has adsorption and adhesion effects on dust and is particularly suitable for road dust suppression.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental pollution control, and specifically provides a dust suppressant, a preparation method and an application thereof. Background Art

[0002] In recent years, atmospheric particulate matter pollution has gradually become one of the most prominent problems in urban air quality. The main pollutant is dust. It not only endangers human health, but is also an important pollution source that affects the urban environment and reduces atmospheric visibility. Road traffic is one of the sources of urban particulate matter emissions. For dusty roads, the use of dust suppressants is an effective solution. However, after general dust suppressants are sprayed, they are prone to "clumping" on the surface of materials, easily form clumped solid-liquid mixtures, have weak dispersion ability, and are also prone to cause secondary dust.

[0003] In view of this situation, there is an urgent need to provide a new type of composite dust suppressant for dust, which can meet the requirements for suppressing road dust in complex environments, reduce the limitations of usage conditions, and expand the application range of dust suppressants. Summary of the Invention

[0004] In order to overcome the above defects, the present invention provides a dust suppressant, a preparation method and an application thereof. The dust suppressant not only has a good adsorption and bonding effect on dust, but also has good hygroscopic water retention and compressive wear resistance, and can greatly reduce secondary dust on roads.

[0005] In the first aspect, the present invention provides a dust suppressant, comprising the following raw materials in parts by weight: Sodium lignosulfonate extracted from lotus stems: 1 - 2 parts; Deionized water: 40 - 60 parts; The first crosslinking agent: 1 - 2 parts; The second crosslinking agent: 1 - 2 parts; Aqueous solution of organic acid: 3 - 4 parts; The first initiator: 1 - 2 parts; and The second initiator: 1 - 2 parts.

[0006] Further, the first crosslinking agent includes one or more of hydroxyethyl methacrylate, acrylamide, and hydroxypropyl acrylate; and / or The second crosslinking agent includes one or two of polyethylene glycol diacrylate and ethylene glycol dimethacrylate.

[0007] Further, the organic acid includes one or more of itaconic acid, maleic acid, and citric acid. The pH of the aqueous solution of the organic acid is 4.8 - 5.5, and the mass fraction of the aqueous solution of the organic acid is 0.3 g / mL - 0.5 g / mL.

[0008] Further, the first initiator includes one or both of ammonium persulfate; and / or The second initiator is potassium persulfate.

[0009] In a second aspect, the present invention provides a method for preparing the dust suppressant, comprising: Obtaining sodium lignosulfonate extracted from lotus stems and dissolving it in deionized water to obtain a first solution; Adding a first crosslinking agent to the first solution, stirring evenly at 50°C - 70°C, then continuing to add a second crosslinking agent and a first initiator, controlling the temperature at 55°C - 75°C under inert gas protection, reacting for 1 - 1.5 hours to obtain a second solution, and controlling the temperature of the second solution to drop to 20 - 25°C; Under inert gas protection, adding an aqueous solution of an organic acid to the cooled second solution, then controlling the temperature to rise to 75°C - 85°C, adding a second initiator, and stirring evenly to obtain a third solution; Vacuum - drying the third solution.

[0010] Further, the method for obtaining the sodium lignosulfonate extracted from lotus stems includes: Crushing and drying lotus stems to obtain a powder; Mixing the powder with a first organic solvent and a second organic solvent, stirring evenly, and then filtering out the solid phase; After drying the solid phase, adding sulfuric acid with a mass fraction of 70% - 75% and stirring at 20 - 25°C for 1 - 3 h to obtain a fourth solution; Adding deionized water to the fourth solution to dilute the sulfuric acid mass fraction to 2.5% - 4%, heating under reflux for 3 - 5 h, cooling, then vacuum - filtering, washing with deionized water at 70 - 90°C until neutral, and drying to obtain lignin; Sulfonating the lignin to obtain sodium lignosulfonate.

[0011] Further, the first organic solvent is one or more of ethanol, methanol, and acetone, the second organic solvent is one or more of benzene, toluene, and cyclohexane, the mass ratio of the powder to the first organic solvent and the second organic solvent is 1:(5 - 11):(8 - 14), and the mass ratio of the solid phase to sulfuric acid with a mass fraction of 70% - 75% is 1:(8 - 12).

[0012] Further, after the step of obtaining sodium lignosulfonate, the method for obtaining the sodium lignosulfonate extracted from lotus stems further includes: Preparing an aqueous solution of sodium lignosulfonate, Completely dissolving the sodium lignosulfonate in deionized water to obtain an aqueous solution of sodium lignosulfonate, Among them, the mass ratio of the sodium lignosulfonate to deionized water is 1:40 - 1:60, that is, 1:(40 - 60); Add a metal salt to the sodium lignosulfonate aqueous solution and stir evenly.

[0013] Furthermore, the metal salt includes one or more of aluminum sulfate, aluminum chloride, and ferric sulfate; and / or The mass ratio of the sodium lignosulfonate to the metal salt is 1:0.4 - 1:0.8, that is, 1: (0.4 - 0.8); and / or The step of adding a metal salt to the sodium lignosulfonate aqueous solution and stirring evenly includes: After adding the metal salt to the sodium lignosulfonate aqueous solution, control the temperature at 50°C - 70°C and stir for 15 - 30 minutes.

[0014] In a third aspect, the present invention provides the use of the dust suppressant described in the first aspect or the dust suppressant prepared by the method in the second aspect in road dust suppression.

[0015] One or more of the above technical solutions of the present invention have at least one or more of the following beneficial effects: The present invention provides a novel composite dust suppressant. Through the specific molecular modification technology of the present invention, sodium lignosulfonate is extracted from lotus stems and prepared, and through graft copolymerization reaction, a novel dust suppressant applied to roads is prepared. This dust suppressant has multiple properties, can effectively inhibit the phenomenon of dust resuspension, and has an adsorption and bonding effect on dust. The dust suppressant of the present invention can very effectively solve the problem of suppressing urban road dust, and provide a strong guarantee for the cleanliness of the urban environment and the health of residents. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Referring to the accompanying drawings, the disclosure of the present invention will become more understandable. It is easy for those skilled in the art to understand that these drawings are only for the purpose of illustration and are not intended to limit the scope of protection of the present invention. In addition, similar numbers in the figures are used to represent similar components, where: Figure 1 is a schematic diagram of the main steps of the preparation method of the dust suppressant according to an embodiment of the present invention; Figure 2 is a schematic diagram of the main steps of the acquisition method of sodium lignosulfonate extracted from lotus stems according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The following describes some embodiments of the present invention with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention and are not intended to limit the scope of protection of the present invention.

[0018] In the description of the present invention, the term "A and / or B" represents all possible combinations of A and B, such as only A, only B, or A and B. The term "at least one A or B" or "at least one of A and B" has a similar meaning to "A and / or B", and can include only A, only B, or A and B. The singular terms "a" and "the" can also include the plural form.

[0019] The present invention discloses a dust suppressant, which comprises the following raw material components: sodium lignosulfonate extracted from lotus stems, deionized water, a first crosslinking agent, a second crosslinking agent, an aqueous solution of an organic acid, a first initiator, and a second initiator. Among them, the sodium lignosulfonate is obtained by extracting from lotus stems. The dust suppressant of the present invention uses lotus stems as raw materials. Compared with extracting lignin from sugarcane, corn straw, walnuts, etc., this material has relatively low impurity content, relatively mild extraction process, higher environmental friendliness, potential high added value, wide sources and low cost. The preparation process is environmentally friendly, and the final product is a high molecular structure mainly composed of carbon chains, which is harmless to personnel and equipment and is easy to biodegradable.

[0020] The dust suppressant of the present invention is prepared from the raw materials of the above components. The proportion of each raw material component is as follows: By weight, Sodium lignosulfonate extracted from lotus stems 1 - 2 parts; Deionized water 40 - 60 parts; The first crosslinking agent 1 - 2 parts; The second crosslinking agent 1 - 2 parts; Aqueous solution of organic acid 3 - 4 parts; The first initiator 1 - 2 parts; and The second initiator 1 - 2 parts.

[0021] In one embodiment, the first crosslinking agent includes one or more of hydroxyethyl methacrylate, acrylamide, and hydroxypropyl acrylate. Preferably, the first crosslinking agent is hydroxyethyl methacrylate HEMA.

[0022] In one embodiment, the second crosslinking agent includes one or two of polyethylene glycol diacrylate and ethylene glycol dimethacrylate. Preferably, the second crosslinking agent is polyethylene glycol diacrylate PEGDA.

[0023] In one embodiment, the organic acid includes one or more of itaconic acid, maleic acid, and citric acid. Preferably, the organic acid is itaconic acid.

[0024] In one embodiment, the pH of the aqueous solution of the organic acid is 4.8 - 5.5. Preferably, the pH of the aqueous solution of the organic acid is 5. The mass fraction of the aqueous solution of the organic acid is 0.3 g / mL - 0.5 g / mL.

[0025] In one embodiment, the preparation method of the aqueous solution of the organic acid includes: weighing 12 g of itaconic acid, dissolving it in 30 ml of deionized water, and then slowly adding 5.2 g of sodium hydroxide solution (the concentration of the sodium hydroxide solution is 40 wt%), controlling the neutralization degree to 70%, so that the pH of the aqueous solution of the organic acid is 5. In one embodiment, the first initiator includes one or both of potassium persulfate and ammonium persulfate, and the first initiator is used as a thermal initiator. Preferably, the first initiator is potassium persulfate.

[0026] The second initiator includes potassium persulfate. The second initiator is used for high-temperature secondary initiation.

[0027] In one embodiment, the sodium lignosulfonate extracted from lotus stems is the sodium lignosulfonate pretreated with metal salts.

[0028] The present invention also discloses a preparation method of the above dust suppressant, weighing each raw material component according to the above ratio. The preparation process refers to Figure 1 , and includes the following steps: S1, obtain sodium lignosulfonate extracted from lotus stems, and dissolve it in deionized water to obtain a first solution.

[0029] S2, add a first crosslinking agent to the first solution, stir evenly at 50°C - 70°C, then continue to add a second crosslinking agent and a first initiator, control the temperature to 55°C - 75°C under inert gas protection, react for 1 - 1.5 hours to obtain a second solution, and control the second solution to cool down to 20 - 25°C.

[0030] S3, under inert gas protection, add the aqueous solution of the organic acid to the cooled second solution, then control the temperature to rise to 75°C - 85°C, add a second initiator, and stir evenly to obtain a third solution.

[0031] S4, vacuum dry the third solution.

[0032] The following explains how the sodium lignosulfonate extracted from lotus stems in step S1 is prepared.

[0033] In one embodiment, in step S1, the method for obtaining the sodium lignosulfonate extracted from lotus stems refers to Figure 2 , and includes: S11, crush and dry the lotus stems to obtain powder; S12. Mix the powder with the first organic solvent and the second organic solvent. After stirring evenly, filter out the solid phase. S13. After drying the solid phase, add sulfuric acid with a mass fraction of 70%-75%, and stir at 20-25°C for 1-3 h to obtain the fourth solution. S14. Add deionized water to the fourth solution to dilute it until the mass fraction of sulfuric acid is 2.5%-4%. Heat under reflux for 3-5 h, cool, then perform vacuum filtration. Wash with deionized water at 70-90°C until neutral, and then dry to obtain lignin. S15. Sulfonate the lignin to obtain sodium lignosulfonate.

[0034] In one embodiment, the temperature of the heat under reflux in step S14 is 25°C.

[0035] In one embodiment, the process of sulfonating the lignin in step S15 includes: S151. Put the lignin prepared in step S14 into an appropriate amount of deionized water, and then add an alkali solution to dissolve it. The purpose of this process is to dissolve the lignin and adjust the alkaline environment to promote the introduction of sulfonic acid groups. Among them, the mass ratio of lignin to alkali solution is 1:0.8 - 1:1.5. The alkali solution is sodium hydroxide or potassium hydroxide solution, and the concentration of the alkali solution is 2-5 wt%.

[0036] In one embodiment, in step S151, the mass ratio of lignin to deionized water is 1:10 - 1:12, that is, 1:(10 - 12). The deionized water in this ratio is only the deionized water used to mix with lignin in step S151.

[0037] S152. Add a sulfonating agent and a catalyst to the product of step S151. The sulfonating agent is used to introduce the group -SO3⁻. The catalyst is used to accelerate the sulfonation reaction and regulate the reaction selectivity.

[0038] In one embodiment, the mass ratio of the sulfonating agent to the catalyst is 1:1.

[0039] S153. Adjust the pH of the product obtained in step S152 to 10.5, raise the temperature to 75-95°C under stirring, and perform the sulfonation reaction for 3-5 h to obtain sodium lignosulfonate.

[0040] In one embodiment, in step S12, the first organic solvent is one or more of ethanol, methanol, and acetone, the second organic solvent is one or more of benzene, toluene, and cyclohexane, and the mass ratio of the powder to the first organic solvent and the second organic solvent is 1:(5 - 11):(8 - 14). Preferably, the mass ratio of the powder to the first organic solvent and the second organic solvent is 1:8:11. The mass ratio of the solid phase to sulfuric acid with a mass fraction of 70% - 75% is 1:(8 - 12). Preferably, the mass ratio of the solid phase to sulfuric acid is 1:10.

[0041] In one embodiment, in step S12, the first organic solvent is ethanol, more specifically absolute ethanol, and the second organic solvent is benzene. The first organic solvent and the second organic solvent form a co-solvent system. The first organic solvent is used to dissolve polar components such as sugars and some phenolic acids. The second organic solvent is used to remove non-polar waxes and lipids.

[0042] In one embodiment, the volume ratio of ethanol to benzene is 160 ml:200 ml.

[0043] In one embodiment, after the step of obtaining sodium lignosulfonate in step S15, the method further includes: S16, pretreating the sodium lignosulfonate.

[0044] The specific process is as follows: S161, completely dissolving the sodium lignosulfonate in deionized water to obtain an aqueous solution of sodium lignosulfonate. In step S161, the mass ratio of the sodium lignosulfonate to deionized water is 1:6 - 1:40, that is, 1:(6 - 40). In this ratio, the deionized water is only the deionized water used to mix with the sodium lignosulfonate in step S161.

[0045] S162, adding a metal salt to the aqueous solution of sodium lignosulfonate and stirring evenly.

[0046] In step S162, the metal salt is slowly added to the aqueous solution of sodium lignosulfonate to reduce the intermolecular repulsion and improve the subsequent polymerization efficiency.

[0047] In one embodiment, the metal salt includes one or more of aluminum sulfate, aluminum chloride, and ferric sulfate. Preferably, the metal salt is aluminum sulfate, Al 3+ Electrostatically crosslinks with sulfonic acid groups.

[0048] In one embodiment, the mass ratio of the sodium lignosulfonate to the metal salt is 1:0.4 - 1:0.8, that is 1:(0.4 - 0.8). The sodium lignosulfonate in this ratio is the sodium lignosulfonate in the aqueous solution of sodium lignosulfonate.

[0049] In one embodiment, in step S162, gold is added to the sodium lignin sulfonate aqueous solution. Salt, stir well including: After adding metal salt to the sodium lignin sulfonate aqueous solution, the temperature is controlled at 50° C.-70° C. and stirred for 15-30 minutes.

[0050] The inert gas in steps S2 and S3 includes nitrogen.

[0051] In step S4, vacuum drying the third solution comprises: S41, vacuum drying the third solution at 50° C. for 24 hours; S42, crushing the dried product from step S41, and then performing Soxhlet extraction with ethanol for 24 hours to remove unreacted monomers; S43, performing secondary drying on the product of step S42 at 50°C for 12 hours to obtain a final dust suppressant product.

[0052] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effects of the present invention, different steps do not have to be performed in such an order. They can be performed simultaneously (in parallel) or in other orders. These changes are within the scope of protection of the present invention.

[0053] In one embodiment, the dust suppressant of the present invention or the dust suppressant prepared by the above preparation method is used in road dust suppression.

[0054] When the dust suppressant of the present invention is used, the weight ratio of the dust suppressant to water is 1:6000. The mixed dust suppressant solution is in liquid form, and the liquid dust suppressant diluted with water is sprayed on the road dust.

[0055] The dust suppressant of the present invention has a significant ability to adsorb and bind dust, effectively adsorbing and binding dust particles in the air. Furthermore, the dust suppressant has good water absorption and water retention, meaning it can absorb and retain large amounts of water, thereby maintaining a moist state in dry environments. It also exhibits excellent compression and wear resistance, maintaining its effectiveness even on heavily trafficked roads. Due to these properties, the dust suppressant of the present invention can significantly reduce the generation of secondary road dust, specifically, reducing the amount of secondary road dust by up to 80%.

[0056] The present invention creatively extracts sodium lignin sulfonate from lotus stems to prepare a dust suppressant. The dust suppressant and preparation method of the present invention have the following advantages: Coupling effect of multi-level pores and active lignin in lotus stems (1) The vascular bundles of lotus stems are loose and porous, which improves the efficiency of lignin extraction. Lotus stems are the stems of aquatic plants. Their vascular bundles are arranged loosely, with thin cell walls and developed air cavities (porosity > 35%), which are significantly different from terrestrial plants (such as corn straw with porosity < 15%). This loose structure makes sulfuric acid more easily penetrate the cell wall, resulting in a higher dissolution rate of lignin and reducing the raw material consumption.

[0057] (2) The G / S / H type ratio of lignin in lotus stems is optimized, with high sulfonation activity. Lotus stem lignin is mainly composed of guaiacyl (G type) and syringyl (S type) (G / S = 1.8:1), and the content of hydroxyphenyl (H type) is < 5%. In contrast, the proportion of H type in walnut husks is > 20%, and the S type in corn straw is relatively low (G / S = 2.5:1).

[0058] This structure enables sulfonic acid groups to be easily introduced in step S15, and the C5 site of the G-type phenylpropane unit is easily attacked by sodium sulfite, with a sulfonation degree of 45% (only 30% in walnut husks).

[0059] The S-type lignin provides more β-O-4 ether bonds and can form stable covalent bonds with HEMA monomers during the crosslinking stage of step S2, increasing the crosslinking density of the product by 30%.

[0060] (3) Lotus stems have a low lignin condensation degree, which can inhibit side reactions. The proportion of β-β' and β-5' condensation structures in lotus stem lignin is < 10%. In contrast, walnut husks promote condensation due to the rich tannic acid (condensation degree > 25%), and corn straw has a condensation degree of about 18% due to high-temperature growth. The low condensation degree reduces phenolic by-products (such as catechol) generated by the cleavage of C-C bonds during the sulfonation process, reducing the generation amount of by-products in step S15 by 60%.

[0061] In step S2, the uncondensed lignin segments are more easily and evenly embedded by the PEGDA crosslinker, and the tensile modulus of the product is increased to 12 MPa (only 8 MPa for walnut husk-based products).

[0062] (4) Lotus stems have the characteristics of low ash and wax content, which can simplify the pretreatment process. The ash content of lotus stems is < 3% (corn straw > 8%), and the epidermal wax content is < 1% (walnut husks > 5%). During the process of obtaining lignin in steps S11 - S14, the low ash content avoids the formation of precipitates between silicate and sulfuric acid, and the light transmittance of the reaction solution is increased to 95% (only 75% in the corn straw system). The low wax content reduces the phase separation phenomenon during the crosslinking stage (step S2), and the water absorption rate of the dust suppressant is < 10% (walnut husk-based products > 18%).

[0063] The preparation process of the dust suppressant of the present invention is described below through examples. Example 1 The dust suppressant of Example 1 of the present invention comprises the following raw materials in parts by weight: 1 part of sodium lignosulfonate extracted from lotus stems; 40 parts of deionized water; 1 part of the first crosslinking agent; 1 part of the second crosslinking agent; 3 parts of an aqueous solution of organic acid; 1 part of the first initiator; and 1 part of the second initiator.

[0064] The preparation method is as follows: S1. Obtain sodium lignosulfonate extracted from lotus stems and dissolve it in deionized water to obtain the first solution.

[0065] In step S1, the specific process of the method for obtaining sodium lignosulfonate extracted from lotus stems is as follows: S11. After the lotus stems are washed with distilled water, cut into sections and dried, they are ground into powder.

[0066] S12. Weigh 15 g of the powder dried in step S11, place it in a 1000 - ml three - necked flat - bottom flask, add 160 ml of the first organic solvent anhydrous ethanol and 200 ml of the second organic solvent benzene, stir magnetically for 48 h, filter out the solid phase, which is the lotus stem powder.

[0067] S13. Wash the lotus stem powder obtained in step S12 twice with ethanol, then wash it three times with distilled water, and then place it in a constant - temperature drying oven and dry it at 100 °C for 24 h, denoted as powder A.

[0068] Take an appropriate amount of the powder and sulfuric acid with a mass fraction of 72%. According to the mass ratio of the solid - phase lotus stem powder to sulfuric acid with a mass fraction of 72% being 1:10, transfer powder A into a 100 - ml beaker, add 20 ml of sulfuric acid with a mass fraction of 72%. In this step, concentrated sulfuric acid depolymerizes the lignin - carbohydrate complex (LCC) to extract lignin. Next, stir at room temperature (20 - 25 °C) for 2 h to obtain the fourth solution.

[0069] S14. Then transfer the fourth solution into a 1000 - ml flat three - necked flask, dilute it with 560 ml of distilled water until the sulfuric acid mass fraction is 3%. The dilute sulfuric acid further hydrolyzes the cellulose residue, heats it under reflux at 25 °C for 4 h, cools it to 20 - 25 °C, then vacuum - filters it, washes the lignin with deionized water at 70 - 90 °C until it is neutral, and then places it in a constant - temperature drying oven and dries it at 100 °C for 48 h to obtain coffee - colored lignin.

[0070] S15. After sulfonating the lignin, sodium lignosulfonate is obtained.

[0071] The process of sulfonating the lignin in step S15 includes: S151, Weigh 10 g of lignin and put it into 100 ml of deionized water. Add 10 mL of a sodium hydroxide solution with a concentration of 3 wt% to dissolve the lignin in water.

[0072] S152, Add 0.3 g of anhydrous sodium sulfite and 0.3 g of ferric chloride to the product of step S151.

[0073] S153, Adjust the pH of the product obtained in step S152 to 10.5 with a sodium hydroxide solution or dilute sulfuric acid. Control the volume of the reaction solution to be less than 150 ml and transfer it to a 250 mL three-neck flask. Heat it to 85 °C with stirring and carry out a sulfonation reaction for 4 h to obtain sodium lignosulfonate.

[0074] S161, Completely dissolve the sodium lignosulfonate in deionized water to obtain an aqueous solution of sodium lignosulfonate. Put 5 g of sodium lignosulfonate into 200 ml of deionized water and stir until completely dissolved to obtain an aqueous solution of sodium lignosulfonate.

[0075] S162, Slowly add 3 g of aluminum sulfate to the aqueous solution of sodium lignosulfonate and stir at 60 °C for 20 minutes.

[0076] Through the above steps, sodium lignosulfonate was successfully extracted from lotus stems. Then, according to the weight ratio of sodium lignosulfonate to deionized water of 1:40, Prepare the first solution. S2, Weigh the first crosslinking agent, the second crosslinking agent, an aqueous solution of organic acid, the first initiator, and the second initiator according to the preset weight ratio in this embodiment.

[0077] Add the first crosslinking agent, 2-hydroxyethyl methacrylate (HEMA), to the solution of step S162 and stir at 60 °C for 10 minutes. Then continue to add the second crosslinking agent, polyethylene glycol diacrylate (PEGDA), and the first initiator, potassium persulfate (K2S2O8). Maintain the reaction at 60 °C for 1 hour under nitrogen protection to obtain a second solution. Control the temperature of the second solution to drop to room temperature, 20 - 25 °C.

[0078] S3, Prepare an aqueous solution of organic acid: First, weigh 12 g of maleic acid, dissolve it in 30 ml of deionized water, and then slowly add 5.2 g of a 40 wt% sodium hydroxide solution to control the neutralization degree to 70% (pH ≈ 5).

[0079] Under nitrogen protection, add the neutralized aqueous solution of maleic acid to the cooled second solution. Then raise the temperature to 80 °C, add the second initiator, potassium persulfate, and stir and react for 1.5 hours until evenly mixed to obtain a third solution.

[0080] S4, Vacuum dry the third solution.

[0081] In step S4, the vacuum drying of the third solution includes: S41, vacuum drying the third solution at 50 °C for 24 hours; S42, putting the product after drying in step S41 into a polytetrafluoroethylene mold, vacuum drying it at 50 °C for 24 hours, crushing it, and then subjecting it to Soxhlet extraction with ethanol for 24 hours to remove unreacted monomers.

[0082] S43, at 50 °C, subjecting the product of step S42 to secondary drying for 12 hours to obtain the final dust suppressant product.

[0083] Example 2 The dust suppressant of Example 2 of the present invention comprises raw materials in the following parts by weight: Sodium lignosulfonate extracted from lotus stems: 2 parts; Deionized water: 60 parts; The first crosslinking agent: 2 parts; The second crosslinking agent: 2 parts; Aqueous solution of organic acid: 4 parts; The first initiator: 2 parts; and The second initiator: 2 parts.

[0084] The preparation method is as follows: S1, obtain sodium lignosulfonate extracted from lotus stems and dissolve it in deionized water to obtain the first solution.

[0085] In step S1, the specific process of the method for obtaining sodium lignosulfonate extracted from lotus stems is as follows: S11, after washing the lotus stems with distilled water, cutting them into sections and drying them, grind them into powder.

[0086] S12, weigh 15 g of the powder after drying in step S11, place it in a 1000 ml three-necked flat-bottom flask, add 200 ml of the first organic solvent methanol and 250 ml of the second organic solvent toluene, stir magnetically for 48 h, filter out the solid phase, i.e., lotus stem powder.

[0087] S13, wash the lotus stem powder obtained in step S12 twice with ethanol, then wash it three times with distilled water, and then place it in a constant temperature drying oven, dry it at 100 °C for 24 h, denoted as powder A.

[0088] Take an appropriate amount of powder and sulfuric acid with a mass fraction of 70%, and mix them according to the mass ratio of solid-phase lotus stem powder to sulfuric acid with a mass fraction of 70% being 1:8. Transfer powder A into a 100-ml beaker, add 25 ml of sulfuric acid with a mass fraction of 70%. In this step, concentrated sulfuric acid depolymerizes the lignin-carbohydrate complex (LCC) to extract lignin. Next, stir for 3 h at room temperature (20 - 25°C) to obtain the fourth solution.

[0089] S14, then transfer the fourth solution into a 1000-ml flat-bottom three-neck flask, dilute it with 600 ml of distilled water to a sulfuric acid mass fraction of 2.5%. Dilute sulfuric acid further hydrolyzes the cellulose residue, heat it under reflux at 25°C for 5 h, cool it to 20 - 25°C, then perform vacuum filtration. Wash the lignin with deionized water at 70 - 90°C until it is neutral, and then place it in a constant-temperature drying oven and dry it at 100°C for 48 h to obtain coffee-colored lignin.

[0090] S15, after sulfonating the lignin, sodium lignosulfonate is obtained.

[0091] The process of sulfonating the lignin in step S15 includes: S151, weigh 10 g of lignin and put it into 120 ml of deionized water, add 15 mL of sodium hydroxide solution with a concentration of 5 wt% to dissolve the lignin in water.

[0092] S152, add 0.5 g of anhydrous sodium sulfite and 0.5 g of ferric chloride to the product of step S151.

[0093] S153, adjust the pH of the product obtained in step S152 to 10.5 with sodium hydroxide solution or dilute sulfuric acid, control the volume of the reaction solution to be less than 150 ml, transfer it to a 250-mL three-neck flask, and heat it to 95°C with stirring for 3 h to obtain sodium lignosulfonate by sulfonation reaction.

[0094] S161, completely dissolve the sodium lignosulfonate in deionized water to obtain an aqueous solution of sodium lignosulfonate. Put 5 g of sodium lignosulfonate into 100 ml of deionized water solution and stir until it is completely dissolved to obtain an aqueous solution of sodium lignosulfonate.

[0095] S162, slowly add 12.5 g of ferric sulfate to the aqueous solution of sodium lignosulfonate and stir at 70°C for 15 minutes.

[0096] Through the above steps, sodium lignosulfonate was successfully extracted from lotus stems. Then, according to the weight ratio of sodium lignosulfonate to deionized water being 2:60, Prepare the first solution.

[0097] S2. Weigh the first crosslinking agent, the second crosslinking agent, the aqueous solution of organic acid, the first initiator, and the second initiator according to the preset weight ratio in this embodiment. Add the first crosslinking agent, i.e., acrylamide, to the solution in step S162, stir at 50 °C for 10 minutes, then continue to add the second crosslinking agent, ethylene glycol dimethacrylate, and the first initiator, ammonium persulfate, and maintain the reaction at 55 °C for 1.5 hours under nitrogen protection to obtain a second solution. Control the temperature of the second solution to drop to room temperature, 20 - 25 °C.

[0098] S3. Prepare the aqueous solution of organic acid: First, weigh 12 g of maleic acid, dissolve it in 40 ml of deionized water, and then slowly add 20 g of 20 wt% sodium hydroxide solution, controlling the neutralization degree to pH ≈ 5.5.

[0099] Under nitrogen protection, add the neutralized aqueous solution of itaconic acid to the cooled second solution, then raise the temperature to 75 °C, add the second initiator, potassium persulfate, and stir and react for 2 hours until evenly mixed to obtain a third solution.

[0100] S4. Vacuum-dry the third solution.

[0101] In step S4, the vacuum-drying of the third solution includes: S41. Vacuum-dry the third solution at 50 °C for 24 hours; S42. Put the product after drying in step S41 into a polytetrafluoroethylene mold, vacuum-dry it at 50 °C for 24 hours, crush it, and then use ethanol Soxhlet extraction for 24 hours to remove unreacted monomers.

[0102] S43. At 50 °C, conduct secondary drying on the product in step S42 for 12 hours to obtain the final dust suppressant product.

[0103] Example 3 The dust suppressant in Example 3 of the present invention comprises the following raw materials in parts by weight: Sodium lignosulfonate extracted from lotus stems 1.5 parts; Deionized water 50 parts; The first crosslinking agent 1.5 parts; The second crosslinking agent 1.5 parts; The aqueous solution of organic acid 3.5 parts; The first initiator 1.5 parts; and The second initiator 1.5 parts.

[0104] The preparation method is as follows: S1. Obtain sodium lignosulfonate extracted from lotus stems and dissolve it in deionized water to obtain a first solution.

[0105] In step S1, the specific process of obtaining sodium lignosulfonate extracted from lotus stems is as follows: S11, After the lotus stems are washed with distilled water, cut into sections and dried, they are ground into powder.

[0106] S12, Weigh 15 g of the powder obtained in step S11, place it in a 1000 ml three-necked flat-bottom flask, add 75 g of the first organic solvent acetone and 120 g of the second organic solvent cyclohexane, stir magnetically for 48 h, and filter out the solid phase, which is the lotus stem powder.

[0107] S13, Wash the lotus stem powder obtained in step S12 twice with ethanol, then wash it three times with distilled water, and then place it in a constant temperature drying oven and dry it at 100 °C for 24 h, denoted as powder A.

[0108] Take an appropriate amount of the powder and sulfuric acid with a mass fraction of 75%. According to the ratio of the solid-phase lotus stem powder to sulfuric acid with a mass fraction of 70% of 1:12. Transfer powder A into a 100 ml beaker, add 22 ml of sulfuric acid with a mass fraction of 75%. In this step, concentrated sulfuric acid depolymerizes the lignin-carbohydrate complex (LCC) to extract lignin. Next, stir at room temperature (20 - 25 °C) for 1 h to obtain the fourth solution.

[0109] S14, Then transfer the fourth solution into a 1000 ml flat-bottom three-necked flask, dilute it with 580 ml of distilled water to a sulfuric acid mass fraction of 4%. The dilute sulfuric acid further hydrolyzes the cellulose residue, heats it under reflux at 25 °C for 3 h, cools it to 20 - 25 °C, then vacuum filters it, washes the lignin with deionized water at 70 - 90 °C until it is neutral, and then places it in a constant temperature drying oven and dries it at 100 °C for 48 h to obtain coffee-colored lignin.

[0110] S15, After sulfonating the lignin, sodium lignosulfonate is obtained.

[0111] The process of sulfonating the lignin in step S15 includes: S151, Weigh 10 g of lignin and put it into 110 ml of deionized water. Add an appropriate amount of potassium hydroxide solution with a concentration of 2 wt% to dissolve the lignin in water. Among them, the mass ratio of lignin to the 2 wt% potassium hydroxide solution is 1:0.8.

[0112] S152, Add 0.4 g of anhydrous sodium sulfite and 0.4 g of ferric chloride to the product of step S151.

[0113] S153, Adjust the pH of the product obtained in step S152 to 10.5 with sodium hydroxide solution or dilute sulfuric acid. Control the volume of the reaction solution to be less than 150 ml and transfer it to a 250 mL three-necked flask. Heat it to 75 °C under stirring and carry out the sulfonation reaction for 5 h to obtain sodium lignosulfonate.

[0114] S161. Completely dissolve the sodium lignosulfonate in deionized water to obtain an aqueous solution of sodium lignosulfonate. Put 5 g of sodium lignosulfonate into 30 ml of deionized aqueous solution and stir until completely dissolved to obtain an aqueous solution of sodium lignosulfonate.

[0115] S162. Slowly add 4 g of aluminum chloride to the aqueous solution of sodium lignosulfonate and stir at 50 °C for 30 minutes. The mass ratio of sodium lignosulfonate to metal salt aluminum chloride in the aqueous solution of sodium lignosulfonate is 1:0.8.

[0116] Through the above steps, sodium lignosulfonate was successfully extracted from lotus stems, and then the sodium lignosulfonate was prepared into a first solution according to the weight ratio of sodium lignosulfonate to deionized water of 1:50. S2. Weigh the first crosslinking agent, the second crosslinking agent, the aqueous solution of organic acid, the first initiator and the second initiator according to the preset weight ratio in this embodiment. Add the first crosslinking agent acrylamide to the solution in step S162 and stir at 70 °C for 10 minutes, then continue to add the second crosslinking agent ethylene glycol dimethacrylate and the first initiator ammonium persulfate, and maintain the reaction at 75 °C for 1.2 hours under nitrogen protection to obtain a second solution, and control the temperature of the second solution to drop to room temperature of 20 - 25 °C.

[0117] S3. Prepare an aqueous solution of organic acid: First, weigh 12 g of itaconic acid, dissolve it in 24 ml of deionized water, and then slowly add an appropriate amount of 20 wt% sodium hydroxide solution to control the neutralization degree pH≈4.8.

[0118] Under nitrogen protection, add the neutralized aqueous solution of itaconic acid to the cooled second solution, then raise the temperature to 85 °C, add the second initiator potassium persulfate, and stir and react for 2 hours to stir evenly to obtain a third solution.

[0119] S4. Vacuum dry the third solution.

[0120] In step S4, the vacuum drying of the third solution includes: S41. Vacuum dry the third solution at 50 °C for 24 hours; S42. Put the product after drying in step S41 into a polytetrafluoroethylene mold, vacuum dry at 50 °C for 24 hours, crush it and then use ethanol Soxhlet extraction for 24 hours to remove unreacted monomers.

[0121] S43. At 50 °C, perform secondary drying on the product in step S42 for 12 hours to obtain the final dust suppressant product.

[0122] The present invention provides a novel composite dust suppressant. Through the specific molecular modification technology of the present invention, sodium lignosulfonate is extracted from lotus stems and prepared. Through graft copolymerization reaction, a novel dust suppressant applied to roads is prepared. This dust suppressant has multiple properties. Through Fourier transform infrared spectroscopy, XRD and other analyses, it can be seen that its structure is conducive to inhibiting the resuspension of dust, and it has an adsorption and bonding effect on dust.

[0123] When the dust suppressant of the present invention is used, the weight ratio of the dust suppressant to water is 1:6000. The liquid dust suppressant after being dissolved and diluted with water is sprayed on road dust. It has an adsorption and bonding effect on dust. The swelling kinetics shows that the dust suppressant of the present invention reaches 33 times of water absorption saturation in 13 hours and is not easy to lose water. When it is 5 - 15 times, it has both wettability and adhesiveness, has compressive and wear resistance, and is not prone to significant deformation due to pressure.

[0124] The swelling kinetics shows that it reaches 33 times of water absorption saturation in 13 hours and is not easy to lose water. When it is 5 - 15 times, it has both wettability and adhesiveness, can inhibit the resuspension of dust, and has good properties such as film hardness.

[0125] The dust suppressants prepared in Examples 1 - 3 were tested. The dust suppressant of the present invention was used for road dust suppression, and the test results are as follows: (I) Having multiple properties Hygroscopicity and water retention: Absorb water in the air and retain water, preventing water from losing from the interior of the material.

[0126] Compressive and wear resistance: After bonding with dust and falling on the road, it will not be damaged or significantly deformed when extruded by external forces such as vehicles.

[0127] Water absorption and regulation: It has water absorption, and the maximum water absorption ratio can reach 33 times, and it can adjust the water absorption ratio according to the actual use environment and can play a role under different humidity conditions.

[0128] Wind resistance and water resistance: The film hardness reaches 84 HA. The formed protective film can effectively resist wind force. The protective film formed after natural drying has elasticity and can resist a certain degree of damage; it has good water resistance, and the protective film formed after water loss can resist rain erosion.

[0129] Strong adhesiveness: It has a strong bonding effect on dust, has a large initial bonding force and a long bonding time, can maintain the adsorption of dust for a long time, and prevent the secondary flying of dust.

[0130] High environmental protection and safety: Using lotus stems as raw materials, the sources are wide and the cost is low. The preparation process is environmentally friendly. The final product is a high - molecular structure mainly composed of carbon chains, which is harmless to personnel and equipment, is easy to biodegradable, and conforms to the theme of environmental protection development.

[0131] (II) Superior performance 1. Dust suppression validity period of the dust suppressant: 35 days ≤ T < 90 days; wind erosion rate < 1.

[0132] 2. The novel composite dust suppressant is completely degraded after 90 days.

[0133] 3. After the dust suppressant is dissolved in water, diluted and sprayed, the thickness of the consolidation layer on the surface of the sprayed material is greater than 10 mm.

[0134] 4. When the spraying amount of the dust suppressant is 4 - 6 kg / m 2 , the dust suppression efficiency ≥ 99.7%.

[0135] 5. The maximum water absorption ratio of the dust suppressant is 33 times, and the water absorption ratio of the product can be adjusted according to the actual use environment.

[0136] 6. The film hardness of the dust suppressant reaches 84 HA, with good wind resistance and water resistance.

[0137] 7. The dust suppressant can withstand a maximum force of 7.2 N, has strong bonding ability and long bonding time. At a wind speed of 8.3 m / s, the mass loss rate is only 1.06%, preventing secondary dust flying.

[0138] When facing roads with flying dust and swirling dust, the dust suppressant must possess a series of key functions such as wetting and moisturizing, bonding and adsorption, solidifying and crusting, and suppressing secondary dust flying. The dust suppressant involved in the present invention can not only dissolve quickly in water, but also possess excellent properties such as wetting and moisturizing, bonding and adsorption, solidifying and crusting mentioned above. Therefore, it can very effectively solve the problem of suppressing urban road dust, providing a strong guarantee for the cleanliness of the urban environment and the health of residents.

[0139] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will all fall within the protection scope of the present invention.

Claims

1. A dust suppressant, characterized in that: The composition comprises the following raw materials in parts by weight: 1-2 parts of sodium lignin sulfonate extracted from lotus stem; 40-60 parts of deionized water; 1-2 parts of the first cross-linking agent; 1-2 parts of the second cross-linking agent; 3-4 parts of an aqueous solution of an organic acid; 1-2 parts of the first initiator; and 1-2 parts of the second initiator.

2. The dust suppressant according to claim 1, characterized in that The first cross-linking agent comprises one or more of hydroxyethyl methacrylate, acrylamide and hydroxypropyl acrylate; and / or The second cross-linking agent includes one or both of polyethylene glycol diacrylate and ethylene glycol dimethacrylate.

3. The dust suppressant according to claim 1, characterized in that The organic acid includes one or more of itaconic acid, maleic acid and citric acid. The pH of the aqueous solution of the organic acid is 4.8-5.5, and the mass fraction of the aqueous solution of the organic acid is 0.3g / mL-0.5g / mL.

4. The dust suppressant according to claim 1 or 3, characterized in that The first initiator includes one or both of ammonium persulfate and ammonium persulfate; and / or The second initiator is potassium persulfate.

5. The method for preparing the dust suppressant according to any one of claims 1 to 4, characterized in that: include: Obtaining sodium lignin sulfonate extracted from lotus stems and dissolving it in deionized water to obtain a first solution; Adding a first crosslinking agent to the first solution, stirring uniformly at 50°C-70°C, then adding a second crosslinking agent and a first initiator, controlling the temperature at 55°C-75°C under inert gas protection, reacting for 1-1.5 hours to obtain a second solution, and controlling the temperature of the second solution to be cooled to 20-25°C; Under inert gas protection, add the aqueous solution of the organic acid to the cooled second solution, then control the temperature to rise to 75°C-85°C, add the second initiator, and stir evenly to obtain a third solution; The third solution was dried under vacuum.

6. The method according to claim 5, characterized in that The method for obtaining sodium lignin sulfonate based on lotus stem extraction comprises: The lotus stems are crushed and dried to obtain powder; mixing the powder with a first organic solvent and a second organic solvent, stirring evenly, and filtering out a solid phase; After drying the solid phase, adding 70%-75% by mass of sulfuric acid, stirring at 20-25° C. for 1-3 hours to obtain a fourth solution; Deionized water was added to the fourth solution to dilute it to a sulfuric acid mass fraction of 2.5%-4%, and the solution was heated under reflux for 3-5 hours. After cooling, the solution was vacuum filtered, washed with deionized water at 70-90° C. until neutral, and dried to obtain lignin; After the lignin is sulfonated, sodium lignin sulfonate is obtained.

7. The method according to claim 6, characterized in that The first organic solvent is one or more of ethanol, methanol and acetone, the second organic solvent is one or more of benzene, toluene and cyclohexane, the mass ratio of the powder to the first organic solvent and the second organic solvent is 1: (5-11): (8-14), and the mass ratio of the solid phase to sulfuric acid with a mass fraction of 70%-75% is 1: (8-12).

8. The method according to claim 6, characterized in that After the step of obtaining sodium lignin sulfonate, the method for obtaining sodium lignin sulfonate based on lotus stem extraction further comprises: Preparation of sodium lignin sulfonate aqueous solution, The sodium lignin sulfonate is completely dissolved in deionized water to obtain a sodium lignin sulfonate aqueous solution, Wherein, the mass ratio of the sodium lignin sulfonate to deionized water is 1: (40-60); Add metal salt to the sodium lignin sulfonate aqueous solution and stir evenly.

9. The method according to claim 8, characterized in that The metal salt comprises one or more of aluminum sulfate, aluminum chloride and ferric sulfate; and / or The mass ratio of the sodium lignin sulfonate to the metal salt is 1:(0.4-0.8); and / or The step of adding a metal salt to the sodium lignosulfonate aqueous solution and stirring the mixture uniformly comprises: After adding metal salt to the sodium lignin sulfonate aqueous solution, the temperature is controlled at 50° C.-70° C. and stirred for 15-30 minutes.

10. Use of the dust suppressant according to any one of claims 1 to 4 or the dust suppressant prepared by the method according to any one of claims 5 to 9 in road dust suppression.

Images