Double-fiber interpenetrating network hydrogel dust suppressant as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of dust suppressants, and particularly discloses a double-fiber interpenetrating network hydrogel dust suppressant and a preparation method and application thereof.The method comprises the following steps that hydroxyethyl cellulose and carboxymethylcellulose are mixed and then stirred; an ammonium persulfate solution and a methylene bisacrylamide solution are obtained; sequentially adding an ammonium persulfate solution and a methylene bisacrylamide solution for reaction, adding absolute ethyl alcohol for soaking, and drying a solid in a drying oven until the weight is constant; and adding a surfactant coconut oil diethanolamide, and stirring until the surfactant is uniformly dispersed. According to the double-fiber interpenetrating network hydrogel dust suppressant as well as the preparation method and the application thereof, the double-fiber interpenetrating network hydrogel dust suppressant prepared by taking carboxymethyl cellulose and hydroxyethyl cellulose as precursors on the basis of free radical graft copolymerization realizes efficient dust suppression; the environmental friendliness and the structural stability are both considered, and the problems of insufficient long-term effect and ecological toxicity of a traditional dust suppressant are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of dust suppressants, and particularly relates to a double-fiber interpenetrating network hydrogel dust suppressant and a preparation method and application thereof. BACKGROUND

[0002] With the continuous improvement of industrialization, coal will still be used for large-scale power and heat production in the short term. However, the problem of coal dust pollution is increasingly prominent. Large-scale mechanized mining and transportation not only increase the risk of dust explosion, but also expose the mining area and its surrounding areas to high-concentration coal dust environments, reduce visibility, damage ecological safety, and endanger the health of miners and nearby residents. The small particle size and dispersibility of coal dust make it easily suspended in a more remote area under dry or strong wind conditions, forming secondary pollution. Therefore, developing an efficient and green dust suppressant is an urgent problem to be solved in the field of mine dust prevention.

[0003] The commonly used dust suppression methods such as water mist spraying or single surfactant treatment can temporarily reduce the concentration of coal dust, but have significant defects such as short action time, poor moisture retention, and easy wind washing. Although common salt dust suppressants have good hygroscopicity, they are easy to deliquesce, have strong corrosion, and poor weather resistance; although synthetic polymers have excellent film-forming properties, they face the difficulties of ecological degradation and long-term toxicity risk.

[0004] In recent years, bio-based polymer materials have gradually become a research hotspot for a new generation of green dust suppressants due to their good renewability, environmental friendliness, and biodegradability. Among bio-based materials, carboxymethyl cellulose (CMC) is widely used for dust binding due to its abundant carboxyl functional groups and low cost. However, single CMC-based gels have insufficient structural stability in dynamic environments due to the easy destruction of hydrogen bond networks by dry-wet cycles. In the variable working conditions of open-pit mines, frequent rainwater flushing and wind action can cause hydrogen bond rupture, leading to micro-cracks or even shedding of the solidified layer under a single structure. In addition, due to the low cross-linking density of the CMC network, the material is difficult to balance strength and toughness. In a high-humidity environment, excessive swelling can cause the structure to be loose, which cannot adapt to the dynamic deformation demand. At the same time, CMC lacks directional binding sites for the hydrophobic surface of coal dust polycyclic aromatic hydrocarbons, and the binding efficiency for complex component dust is limited, which is difficult to inhibit secondary dusting caused by water evaporation.

[0005] Therefore, there is a need in the art to develop a double-fiber interpenetrating network hydrogel dust suppressant and a preparation method and application thereof, which can effectively solve the above problems. SUMMARY

[0006] The purpose of this invention is to provide a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application. The preparation method is based on a free radical graft copolymerization reaction, using carboxymethyl cellulose and hydroxyethyl cellulose as precursors. The prepared dual-fiber interpenetrating network hydrogel dust suppressant achieves high-efficiency dust suppression while taking into account environmental friendliness and structural stability, thus solving the problems of insufficient long-term effectiveness and ecotoxicity of traditional dust suppressants.

[0007] To achieve the above objectives, the present invention provides a method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant, comprising the following steps:

[0008] Step S1: Weigh carboxymethyl cellulose and hydroxyethyl cellulose. First, add hydroxyethyl cellulose to a three-necked flask and add 150-200 ml of aqueous solution to dissolve it, so as to obtain a clear solution A.

[0009] Step S2: Add carboxymethyl cellulose to solution A and stir until it becomes transparent and free of bubbles, to obtain solution B;

[0010] Step S3: Weigh ammonium persulfate (APS) and methylenebisacrylamide (MBA), and dissolve ammonium persulfate and methylenebisacrylamide in 5 mL of aqueous solution to obtain ammonium persulfate solution and methylenebisacrylamide solution respectively.

[0011] Step S4: After passing nitrogen gas into solution B, stir it. During the stirring process, add ammonium persulfate solution and methylenebisacrylamide solution to solution B in sequence to react. After the reaction is completed, cool to room temperature to obtain crude product A.

[0012] Step S5: Transfer crude product A to a beaker, add anhydrous ethanol for soaking, remove the solid, and dry the solid in an oven to constant weight to obtain crude product B;

[0013] Step S6: Add the surfactant coconut oil diethanolamide (CDEA) to the crude product B and stir until it is evenly dispersed to obtain the double fiber interpenetrating network hydrogel dust suppressant (CMC-HEC / CDEA).

[0014] Preferably, in step S1, the mass of carboxymethyl cellulose is 6-8g and the mass of hydroxyethyl cellulose is 2.5-3g; the dissolution time is 3-4min.

[0015] Preferably, in step S2, the stirring temperature is 70°C.

[0016] Preferably, in step S3, the mass of ammonium persulfate is 0.01-0.03g, and the mass of methylenebisacrylamide is 0.2-0.3g.

[0017] Preferably, in step S4, the nitrogen gas is introduced for 30 minutes; and the stirring temperature is 85°C.

[0018] The ammonium persulfate solution and methylenebisacrylamide solution were added at intervals of 10-15 minutes, and the reaction time was 45 minutes.

[0019] Preferably, in step S5, the amount of anhydrous ethanol added is 200 mL; the soaking time is 1 h.

[0020] Preferably, in step S6, the mass percentage concentration of the surfactant coconut oil diethanolamide in the bifid interpenetrating network hydrogel dust suppressant is 0.1%-0.2%.

[0021] The present invention also provides a method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant.

[0022] This invention also provides an application of a dual-fiber interpenetrating network hydrogel dust suppressant in ecological dust suppression in open-pit mines.

[0023] This invention employs the aforementioned dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application, with the following beneficial effects:

[0024] (1) The preparation method of the present invention uses carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (HEC) as raw materials, and constructs a three-dimensional network structure through graft copolymerization and crosslinking. The hydroxyl groups on the molecular chain of hydroxyethyl cellulose and the carboxyl groups of carboxymethyl cellulose form hydrogen bonds to form a rigid and flexible interpenetrating network, thereby achieving a gel system with both strength and toughness. In this way, an environmentally friendly dust suppressant with high stability and ecological degradability is prepared to meet the dual challenges of dynamic load and complex environment of open mines on the structure of dust suppressants.

[0025] (2) The dust suppressant prepared by this invention has excellent structural stability, dust suppression performance and ecological degradation ability. Its viscosity can reach 243.2 mPa·s and the shell thickness is 7.55 mm, thus showing good application potential and promotion prospects, providing a new path and research basis for the construction of green mines and the development of ecological dust suppression technology.

[0026] (3) Compared with traditional dust suppressants, the dust suppressant prepared in this invention significantly reduces carbon emissions throughout its entire life cycle, effectively saves water resources, and optimizes energy efficiency by reducing the frequency of operation. Moreover, the dust suppressant prepared in this invention has a natural degradation rate of 83.5% in soil within 50 days, and the final product is non-toxic, thus achieving an ecological closed loop from "structural stability to green degradation".

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a diagram showing the surface tension measurement results in Experiment 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0029] Figure 2 This is a contact angle measurement diagram from Experiment 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0030] Figure 3 This is a figure showing the sedimentation test results in Experiment Example 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0031] Figure 4 This is a model diagram of CMC-HEC molecules, coal dust molecules, water molecules, and an exchange chamber in Experiment 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0032] Figure 5 This is a molecular dynamics simulation diagram of the adsorption process in Experiment Example 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0033] Figure 6 This is a graph showing the adsorption energy versus kinetics in Experiment 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0034] Figure 7 This is a diagram showing the effect of hydrogen bond interactions within the gel network in Experiment 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0035] Figure 8 This is a figure showing the anti-evaporation test results of an experimental example 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0036] Figure 9 This is a diagram showing the wind erosion test results in Experiment 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0037] Figure 10 This is a diagram showing the water erosion resistance test results of the cured layer in Experiment Example 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0038] Figure 11 The image shows the scanning electron microscope (SEM) results of coal dust treated in Experiment 1 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application. In the figure, (a) is water treatment, (b) is CDEA solution treatment, and (c) and (d) are both CMC-HEC / CDEA treatment.

[0039] Figure 12 The X-ray diffraction spectra of coal dust treated with CMC-HEC / CDEA and coal dust treated with aqueous solution in Experiment Example 1 of the present invention, a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method and application, are shown.

[0040] Figure 13 This is a graph showing the degradation rate test of the CMC-HEC / CDEA cured film over time in Experiment Example 2 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application.

[0041] Figure 14 This is a comprehensive life cycle assessment diagram for the experimental example 3 of the present invention, which describes a dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method, and its application. Detailed Implementation

[0042] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0044] The coal powder used in this invention is sourced from Yulin City, Shaanxi Province, China, and is a bituminous coal.

[0045] Example

[0046] A method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant includes the following steps:

[0047] Step S1: Add 2.5g of hydroxyethyl cellulose to a 200mL three-necked flask, add 150mL of aqueous solution and dissolve for 3min to obtain a clear solution A;

[0048] Step S2: Add 6g of carboxymethyl cellulose to solution A and stir at 70°C until it becomes transparent and free of bubbles, to obtain solution B;

[0049] Step S3: Weigh 0.01g of ammonium persulfate and 0.3g of methylenebisacrylamide, and dissolve the ammonium persulfate and methylenebisacrylamide in 5mL of aqueous solution to obtain ammonium persulfate solution and methylenebisacrylamide solution respectively.

[0050] Step S4: After passing nitrogen gas through solution B for 30 min, stir at 85°C. During the stirring process, add ammonium persulfate solution and methylene bisacrylamide solution to solution B in sequence for reaction. The interval between adding ammonium persulfate solution and methylene bisacrylamide solution is 15 min. After the reaction is completed for 45 min, cool to room temperature to obtain crude product A.

[0051] Step S5: Transfer crude product A to a 500mL beaker, add 200mL of anhydrous ethanol and soak for 1h, remove the solid, put the solid in an oven and dry to constant weight to obtain crude product B;

[0052] Step S6: Add 1 mL of the surfactant coconut oil diethanolamide to the crude product B and stir until it is evenly dispersed to obtain the double fiber interpenetrating network hydrogel dust suppressant (CMC-HEC / CDEA).

[0053] Experimental Example 1

[0054] The performance of the dual-fiber interpenetrating network hydrogel dust suppressant, surfactant CDEA solution, and aqueous solution prepared in the examples was tested.

[0055] (a) Wetness test.

[0056] (1) Contact angle measurement.

[0057] The instantaneous contact and diffusion wetting characteristics of different droplets colliding with coal dust were simulated and compared. The optical contact angles of CMC-HEC / CDEA, CDEA solution, and aqueous solution were measured. Surface tension was tested before measurement to determine the critical micelle concentration (CMC) of CMC-HEC / CDEA and CDEA solution, which was then used as the optimal working concentration. Dynamic measurements were recorded from 0 to 120 minutes to evaluate wetting behavior.

[0058] like Figure 1 As shown, the surface tension values ​​of the CDEA solution and CMC-HEC / CDEA tend to stabilize when the solute concentration reaches approximately 0.1%, indicating that this concentration is close to their respective critical micelle concentrations (CMC). Based on this observation, contact angle measurements were subsequently performed using solutions of this representative concentration to ensure the scientific validity and comparability of the wettability assessment.

[0059] like Figure 2 As shown, compared with the aqueous solution, the contact angles of CDEA solution and CMC-HEC / CDEA on the coal cake surface are significantly different. The contact angles of aqueous solution, CDEA solution and CMC-HEC / CDEA are 62°, 51° and 60°, respectively.

[0060] The aqueous solution droplets exhibited a large contact angle on the coal cake surface, remaining at 62° for over 30 seconds, indicating incomplete diffusion and insufficient contact with the coal surface, resulting in poor wettability. In contrast, both CMC-HEC / CDEA and CDEA solutions significantly reduced the contact angle on the coal cake surface, improving its wetting and spreading abilities. This demonstrates that the droplets from CMC-HEC / CDEA and CDEA solutions exhibited significantly improved wetting ability on coal compared to the aqueous solution.

[0061] For CMC-HEC / CDEA, the contact angle gradually decreased from 60° to 33° within 60 seconds. Over time, the CMC-HEC / CDEA components gradually adhered to the coal dust surface, which facilitated better water contact and penetration.

[0062] Although the contact angle of the CDEA solution decreased significantly from 51° to 25° within the same time period, indicating its stronger wetting ability on the coal cake surface, the CDEA solution has a simple structure, and using only CDEA solution cannot provide long-term and effective dust suppression.

[0063] The addition of CDEA solution in the examples utilizes the amphiphilic nature of CDEA solution, which allows it to adsorb and extend molecules at the coal interface, reducing surface tension and promoting droplet spreading. This enhances the wetting properties of the prepared CMC-HEC / CDEA.

[0064] (2) Settlement test.

[0065] The static sedimentation method was used to analyze the agglomeration inhibition effect of a double-fiber interpenetrating network hydrogel dust suppressant on coal dust. Three groups of experiments were set up, in which 0.1 g of coal dust was added to 25 mL of LCMC-HEC / CDEA solution, 25 mL of LCMC-HEC / CDEA solution, and 25 mL of aqueous solution, respectively. The dispersion and sedimentation process of coal dust in different solutions were observed and recorded.

[0066] like Figure 3 As shown, from left to right, the three test tubes contain CMC-HEC / CDEA, a surfactant solution, and water, respectively. When coal dust comes into contact with the liquid surface, it undergoes a wetting process. The CDEA solution, due to its amphiphilic molecular structure, rapidly reduces surface tension and completely wets the coal dust particles within 30 seconds through capillary penetration, forming a monomolecular adsorption layer. In contrast, the CMC-HEC polymer chains in CMC-HEC / CDEA, through the synergistic effect of carboxymethyl and hydroxyethyl groups, gradually construct a three-dimensional interpenetrating network structure on the coal dust surface, requiring 80 seconds to complete the dynamic wetting process. This lag stems from the kinetic limitations of polymer chain conformation adjustment and interfacial hydrogen bond reconstruction. Water, due to its high surface tension and lack of active groups, cannot overcome the hydrophobic surface energy barrier of the polycyclic aromatic hydrocarbons in the coal dust, resulting in wetting failure.

[0067] After 20 minutes, the upper part of the test tube became noticeably clearer and more transparent. A significant sedimentation effect was observed within 80-100 minutes. The area of ​​transparent liquid at the top of test tube A was larger than that of test tube B, indicating that CMC-HEC / CDEA causes coal dust particles to settle at a faster rate. The larger molecular weight and surface area of ​​the CMC-HEC / CDEA components facilitate their adhesion to coal dust particles, forming a broader sedimentation system and thus achieving rapid sedimentation within the solution.

[0068] (3) Molecular dynamics simulation.

[0069] like Figure 4 As shown, molecular models of CMC-HEC / CDEA and coal powder polycyclic aromatic hydrocarbons were first constructed using MS2024. Geometric optimization was performed on individual structures using the SMART method and COMPASSII force field; the electrostatic summation method was PPPM, and the van der Waals summation method was atom-based. An amorphous model was then constructed using the Amorphous Cell module, filled with 5 coal molecules, 5 CMC-HEC molecules, and 1200 water molecules, with an initial density of 0.6 g / cm³. 3 The low initial density facilitates full relaxation of the structure; the kinetic ensemble is NPT, the temperature is 300K, the pressure is one atmosphere, and the simulation time is 300 ps. The binding energy between the adsorbed structure and molecules is analyzed.

[0070] like Figure 5 As shown, molecular dynamics simulations revealed the dynamic adsorption mechanism between CMC-HEC / CDEA and coal molecules. In the initial stage (0 ps), coal molecules are predominantly planar structures of polycyclic aromatic hydrocarbons, with CMC-HEC molecules distributed above the coal surface via polar groups of carboxymethyl and hydroxyethyl groups. As the simulation time increases (0 to 100 ps), the carboxyl groups of CMC and the oxygen-containing groups on the coal molecule surface gradually form a face-to-face oriented arrangement through electrostatic attraction. Simultaneously, the flexible segments of HEC physically entangle and wrap around the edges of coal particles, essentially completing the adsorption configuration at 150 ps. In this process, electrostatic interaction dominates the initial adsorption localization, while van der Waals forces further strengthen the interfacial bonding through the accumulation of hydrophobic segments of the molecular chains and the aromatic hydrocarbon structure of the coal. The total adsorption energy is -465.6 kJ / mol.

[0071] like Figure 6 As shown in the figure, the trend of interaction energy changes reveals that electrostatic energy significantly affects the adsorption process. This is because electrostatic energy may dominate adsorption in regions with dense polar functional groups due to strong electrostatic attraction. Furthermore, as the kinetic simulation progresses, the total adsorption energy fluctuates dramatically within the first 100 ps, ​​reflecting the conformational adjustment of adsorbate molecules during dynamic binding with the CMC-HEC / CDEA surface. While fluctuations still exist after ps > 100, the overall magnitude of change decreases, indicating that the system gradually approaches adsorption equilibrium after 100 ps, ​​and energy release tends to stabilize. This is related to the dynamic equilibrium reached by interfacial interactions after the initial adsorption of molecules.

[0072] The rigid skeleton of CMC fixes the spatial position of coal particles through electrostatic action, while the flexible chain of HEC buffers external shear forces through dynamic entanglement. The two work together to achieve dual protection of "anchoring and buffering".

[0073] In addition, such asFigure 7 As shown, the hydrogen bond network formed between key functional groups within the system is illustrated. The hydrogen bonds between carboxyl and hydroxyl groups are relatively stable, while hydrogen atoms in the amino group also interact with methoxy or carbonyl groups via hydrogen bonding. These synergistic multiple hydrogen bonds significantly enhance the structural stability of CMC-HEC / CDEA and improve its adhesion to coal dust surfaces, thus providing a solid foundation for its resistance to wind erosion and wettability.

[0074] (ii) Dust suppression performance test.

[0075] (1) Resistance to evaporation.

[0076] Equal amounts of 20g coal dust samples were evenly distributed in multiple petri dishes of the same size. Then, using a spray bottle, CMC-HEC / CDEA, an aqueous solution, and CDEA solution were evenly sprayed onto the coal dust surface, ensuring the surface was completely wetted. After the coal dust surface was completely wetted, the petri dishes were placed in a drying oven and subjected to an evaporation resistance test at 35°C. The weight of each sample was recorded at the start of the test and at specific time intervals (0, 1, 2, 3, 4, 6, 8, 12, and 24 hours). The water retention rate of the sample was calculated using the following formula:

[0077]

[0078] In the formula, E is the water retention rate (%) of the coal dust sample; M0 is the initial mass, that is, the total mass (g) of the petri dish and coal dust before spraying the solution; M1 is the mass (g) of the petri dish after spraying the solution; and M2 is the mass (g) of the petri dish measured at specific time intervals.

[0079] By calculating the water retention rate at different time points, the water retention effect of CMC-HEC / CDEA under different ambient temperatures can be evaluated, thereby determining its dust suppression duration and performance stability.

[0080] like Figure 8 As shown, CMC-HEC / CDEA achieves long-term dust suppression through a triple synergistic mechanism of "hydrogen bond water locking - pore confinement - dynamic recombination". Its water retention process exhibits three-stage characteristics: in the initial stage (0-4h), surface free water evaporates rapidly driven by the environment; in the middle stage (4-12h), the three-dimensional network anchors bound water through hydrogen bonds and delays diffusion with the help of porous supports; and in the later stage (12-24h), dynamic hydrogen bond recombination under low moisture conditions inhibits film cracking, achieving a water retention rate of >29% in 24 hours.

[0081] In contrast, the physical liquid film formed by monomolecular wetting of CDEA solution lacks chemical cross-linking support and breaks down rapidly under drying stress, losing more than 95% of its water within 8 hours; while pure water, lacking structured water retention, allows water to evaporate freely, resulting in a water retention rate close to zero within 24 hours.

[0082] Therefore, the interpenetrating network of CMC-HEC / CDEA balances moisture release and structural stability through chemical-physical multi-scale interactions, providing a long-term solution for coal dust control in complex environments.

[0083] (2) Wind erosion resistance test.

[0084] A small-scale wind tunnel testing apparatus (CZT centrifugal AC blower) was used to conduct dust suppression tests on coal dust samples treated with CMC-HEC / CDEA, aqueous solution, and CDEA solution. First, 200g of dry coal dust was evenly placed in a 28cm×18cm×2cm tray. Then, the prepared solution was evenly sprayed onto the coal dust surface, ensuring complete coverage. The sprayed samples were allowed to air dry, and wind erosion tests were conducted after the surface was completely cured. In the wind tunnel tests, wind speeds of 3m / s, 5m / s, 7m / s, and 9m / s were set, with the wind direction at a 45° angle to the sample surface, and exposure was continuous for 30 minutes. After each stage, the mass change of the sample was precisely measured. The dust suppression rate was used to evaluate the curing effect of the dust suppressant on coal dust, and its calculation formula is as follows:

[0085]

[0086] In the formula, K is the solidified coal dust loss rate (%); G is the original coal dust mass (g); and G0 is the coal dust mass (g) after the wind resistance test.

[0087] like Figure 9 As shown, comparative analysis through wind erosion resistance experiments revealed that CMC-HEC / CDEA exhibits significant performance advantages in dynamic airflow environments. Its three-dimensional interpenetrating network, through the synergistic effect of chemical bonding and physical entanglement between carboxymethyl and hydroxyethyl groups, forms a dense barrier layer on the coal dust surface that combines rigidity and toughness, effectively resisting airflow stripping stress. At the microscopic level, the hydrogel network anchors coal dust particles through multiple hydrogen bonds, while flexible segments dynamically buffer shear forces and inhibit crack propagation, thus maintaining structural integrity even under high wind speeds.

[0088] In contrast, CDEA solution relies on a monolayer wetting mechanism, which can temporarily reduce the surface tension of coal dust to form a liquid film, but lacks chemical cross-linking. The physical adsorption interface will break down rapidly under the impact of airflow, causing the particles to break apart. Pure water treatment only produces weak adsorption through physical wetting. After the water evaporates, there is no structural residue, and the coal dust particles are directly exposed to the airflow.

[0089] As wind speed increases (3→9 m / s), the loss rate of CMC-HEC / CDEA increases gradually, indicating that its network structure has stress adaptability; while the loss rate of CDEA solution and aqueous solution increases exponentially, revealing the inadequacy of physical wetting mechanism in terms of environmental tolerance.

[0090] CMC-HEC / CDEA exhibits an excellent wind erosion resistance with a wind erosion rate of only 5.8% at a wind speed of 9 m / s. CMC-HEC / CDEA achieves "structural dust suppression" through multi-scale synergistic effects.

[0091] (3) Water erosion resistance test of the cured layer.

[0092] Coal dust was evenly spread in a petri dish. CMC-HEC / CDEA, CDEA solution, and aqueous solution were sprayed onto the surface of the coal dust until it was completely wetted. The dish was then dried at room temperature to constant weight, and the initial total mass M was recorded. a The sample was then immersed in an aqueous solution and allowed to stand for 10 minutes. After removal, the integrity of the cured layer surface was observed, and the sample was dried in an oven at 40°C until constant weight. The residual total mass M was recorded. i Repeat the soaking-drying process 5 times. The calculation formula is as follows:

[0093]

[0094] In the formula, Q is the mass loss rate (%), and M... i M represents the total mass (g) after the i-th cycle; i-1 M represents the total mass after the (i-1)th cycle; a denoted as the initial total mass (g); n is the mass of the petri dish (g).

[0095] like Figure 10 As shown, the CMC-HEC / CDEA treatment group formed a continuous and dense cross-linked network layer on its surface, with only slight wrinkles in some areas. The coal dust particles were firmly encapsulated, and only a small amount of fine powder was lost. In contrast, the CDEA solution and aqueous solution treatment groups lacked structural protection, resulting in the loss of most of the coal dust (loss rates of 72.6% and 82%, respectively).

[0096] After five water erosion cycles, the cumulative mass loss rate of CMC-HEC / CDEA was only 0.6%, far lower than that of CDEA solution (72.6%) and deionized water (82%). In CMC-HEC / CDEA, CMC-HEC forms an elastic and tough protective layer, and its dynamic hydrogen bonds can partially recombine during water erosion, inhibiting crack propagation. In contrast, CDEA solution, relying solely on physical adsorption, cannot resist repeated water erosion. CMC-HEC / CDEA, with its stable chemical bonding and self-healing network, significantly enhances the water erosion resistance of coal dust.

[0097] (5) Perform scanning electron microscopy (SEM) tests.

[0098] First, CMC-HEC / CDEA, CDEA solution, and aqueous solution were drop-cast onto a pretreated copper substrate and then vacuum-dried and cured to form a uniform thin film. Subsequently, before SEM characterization, the sample underwent surface treatment optimization: high-purity nitrogen was used to remove physically adsorbed impurities from the surface, and an approximately 5 nm thick gold film (Au-Pd target, sputtering current 15 mA, time 120 s) was deposited on the film surface using an ion sputtering instrument to eliminate the charging effect and enhance the secondary electron emission signal, ensuring the accuracy of high-resolution microscopic imaging.

[0099] like Figure 11 As shown in (a), due to the lack of chemical binders, the coal dust particles treated with the aqueous solution are loosely aggregated, with rough surfaces and numerous exposed pores, bound together only by weak van der Waals forces. After moisture evaporation, the drying shrinkage stress causes microcracks and fracture structures to form on the surface, further exposing the hydrophobic surface of the coal dust and exacerbating the risk of secondary dust generation. Figure 11 As shown in (b), the coal dust particles are more evenly dispersed due to the thorough wetting by the CDEA solution, the original pores of the coal dust are filled, and the surface tends to be smooth and compact. Figure 11 (c)- Figure 11 As shown in (d), the surface of the coal dust is tightly wrapped with CMC-HEC / CDEA fibers, forming a "fiber-particle" composite structure. Some of the coal dust is embedded in the gaps between the CMC-HEC / CDEA sheets, presenting a semi-encapsulated state.

[0100] Formation of a dense surface layer: CMC-HEC / CDEA forms a continuous coating film on the coal dust surface. The lamellar structure of CMC and the flexible chains of HEC are interwoven on the film surface, filling the gaps between coal dust particles and significantly reducing the exposed surface area. The carboxyl and hydroxyethyl groups in CMC-HEC / CDEA form hydrogen bonds or electrostatic adsorption with the oxygen-containing groups on the coal dust surface. The sharp edges of the coal dust particles are wrapped by the flexible chains of HEC. The hydrogel forms a thickened buffer layer at the particle corners, preventing interfacial cracking under drying or external force.

[0101] (4) X-ray diffraction (XRD) test.

[0102] X-ray diffraction was used to characterize the crystal structure of coal samples treated with CMC-HEC / CDEA and aqueous solution. The testing system was equipped with a CuKα radiation source (λ = 1.5406 nm), operating voltage 40 kV, current 40 mA, scanning range covering a 2θ reflection angle of 5°–60°, scanning rate set to 10° / min, and sampling step width 0.02°. The evolution of the crystalline phases of the material was analyzed to determine whether the graft copolymerization process induced amorphous region expansion, lattice distortion, or other aggregated structure reconstruction phenomena.

[0103] like Figure 12As shown, in the XRD pattern of coal dust treated with aqueous solution, two peaks appeared at 26.74° and 29.58°. 26.74° corresponds to the (101) crystal plane diffraction peak of quartz. Quartz is a common stable mineral in coal dust, and water treatment does not dissolve or change its crystal structure, so the peak position remains stable. The presence of this peak indicates that the sample contains quartz particles, which originate from inorganic impurities or associated minerals in the coal. 29.58° corresponds to the crystal plane diffraction peak of calcite, which comes from carbonate minerals or external sediments in the coal dust. During aqueous solution treatment, the weakly acidic or neutral conditions in the water (pH≈6-8) slightly dissolve the surface of calcite, causing a slight shift in the peak.

[0104] In the XRD pattern of coal dust treated with CMC-HEC / CDEA, new characteristic peaks appeared at 32.78°, 46.38°, and 55.86°, which were attributed to sodium chloride (NaCl) diffraction peaks by phase analysis. The NaCl diffraction peaks are attributed to the presence of sodium carboxymethyl cellulose (CMC-Na) in the dust suppressant used, which provides Na₂O₃. + However, Cl- ions are present in coal dust itself or in the surrounding environment. CMC-HEC / CDEA can remove Na+ ions. + It is carried and permeates into the pores of coal dust; as the moisture evaporates, the Na in the pores... + Cl- gradually concentrates and crystallizes to precipitate NaCl. The resulting NaCl crystals are deposited in the form of particles and embedded inside the coal dust-hydrogel composite structure, filling the pores and thus enhancing the compactness of the surface layer.

[0105] Experimental Example 2

[0106] Biodegradability analysis was performed on the CMC-HEC / CDEA prepared in the examples.

[0107] CMC-HEC / CDEA was uniformly sprayed onto the surface of a 2 mm thick coal dust sample and placed in a vacuum oven at 60 °C until the sample reached constant weight. Then, the sample was transferred to room temperature (25 °C) for 10 degradation cycles (5 days per cycle). At the end of each cycle, the mass change of the sample was recorded and weighed.

[0108] like Figure 13 As shown, the degradation process of CMC-HEC / CDEA exhibits a typical three-stage dynamic evolution pattern.

[0109] Initial stage: Surface erosion stage, microorganisms preferentially decompose the ether bonds and short-chain polysaccharides on the surface, releasing oligosaccharide fragments through enzymatic hydrolysis, thus disintegrating the surface structure of the material; Intermediate stage: Bulk disintegration stage, the three-dimensional network backbone of the hydrogel undergoes rapid hydrolysis under the synergistic effect of soil moisture and microorganisms, with the β-1,4 glycosidic bond breakage of the cellulose backbone dominating the degradation process, and the increased network porosity accelerating the disintegration of the bulk structure; Late stage: Residual mineralization stage, the remaining cross-linked structures are gradually converted into carbon dioxide and water through microbial metabolic pathways, while generating humic substances to improve the soil organic matter content.

[0110] The solidified film has a natural degradation rate of up to 83.5% in soil after 50 days. The entire degradation pathway follows the ecological cycle mechanism of "surface erosion - bulk phase disintegration - complete mineralization". The degradation half-life is short and the final products are non-ecotoxic, which confirms the dual environmental compatibility characteristics of CMC-HEC / CDEA: "stable structure during service and rapid degradation after disposal".

[0111] This phase-responsive degradation behavior stems from the multi-scale structural design of the material: the hydrophilic ether bonds on the surface provide initial biological contact sites, the glycosidic bonds in the main network endow it with controllable hydrolysis characteristics, and the appropriate crosslinking density balances the contradiction between service stability and degradation rate, ultimately achieving synergistic optimization of dust suppression function and environmental friendliness.

[0112] Experimental Example 3

[0113] Life cycle assessment (LCA) was performed on the CMC-HEC / CDEA prepared in the examples.

[0114] The LCA study follows the principles and framework specified in ISO 14040 and ISO 14044 standards. The system boundaries evaluated are set at 1 ton of CMC-HEC / CDEA finished product, including: upstream raw material sourcing and production, the dust suppressant manufacturing process, the usage stage, and the waste / final disposal stage.

[0115] like Figure 14 As shown, CMC-HEC / CDEA outperforms traditional salt and organic polymer dust suppressants in all four dimensions: carbon emissions, water consumption, energy consumption, and ecotoxicity. CMC-HEC / CDEA also demonstrates significant advantages in its life cycle environmental performance.

[0116] CMC-HEC / CDEA combines the renewable and biodegradable properties of bio-based materials with highly efficient and long-lasting dust suppression capabilities. It outperforms traditional salt and organic polymer dust suppressants in reducing carbon emissions, conserving water resources, lowering energy consumption, and mitigating ecotoxicity. This indicates that CMC-HEC / CDEA has significant potential for application in dust control in mining and other sectors, not only enhancing dust suppression effects but also contributing to environmentally friendly and sustainable development goals.

[0117] Therefore, the present invention adopts the above-mentioned dual-fiber interpenetrating network hydrogel dust suppressant, its preparation method and application. The preparation method is based on free radical graft copolymerization reaction, using carboxymethyl cellulose and hydroxyethyl cellulose as precursors. The prepared dual-fiber interpenetrating network hydrogel dust suppressant achieves high-efficiency dust suppression while taking into account environmental friendliness and structural stability, and solves the problems of insufficient long-term effect and ecotoxicity of traditional dust suppressants.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant, characterized in that, Includes the following steps: Step S1: Weigh carboxymethyl cellulose and hydroxyethyl cellulose. First, add hydroxyethyl cellulose to a three-necked flask and add 150-200 ml of aqueous solution to dissolve it, so as to obtain a clear solution A. Step S2: Add carboxymethyl cellulose to solution A and stir until it becomes transparent and free of bubbles, to obtain solution B; Step S3: Weigh out ammonium persulfate and methylenebisacrylamide, and dissolve them in 5 mL of aqueous solution to obtain ammonium persulfate solution and methylenebisacrylamide solution respectively. Step S4: After passing nitrogen gas into solution B, stir it. During the stirring process, add ammonium persulfate solution and methylenebisacrylamide solution to solution B in sequence to react. After the reaction is completed, cool to room temperature to obtain crude product A. Step S5: Transfer crude product A to a beaker, add anhydrous ethanol for soaking, remove the solid, and dry the solid in an oven to constant weight to obtain crude product B; Step S6: Add the surfactant coconut oil diethanolamide to the crude product B and stir until it is evenly dispersed to obtain the double fiber interpenetrating network hydrogel dust suppressant.

2. The method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant according to claim 1, characterized in that: In step S1, weigh 6-8g of carboxymethyl cellulose and 2.5-3g of hydroxyethyl cellulose; dissolve for 3-4 minutes.

3. The method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant according to claim 1, characterized in that: In step S2, the stirring temperature is 70°C.

4. The method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant according to claim 1, characterized in that: In step S3, 0.01-0.03 g of ammonium persulfate and 0.2-0.3 g of methylenebisacrylamide are weighed.

5. The method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant according to claim 1, characterized in that: In step S4, nitrogen gas is introduced for 30 minutes; the stirring temperature is 85°C. The ammonium persulfate solution and methylenebisacrylamide solution were added at intervals of 10-15 minutes, and the reaction time was 45 minutes.

6. The method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant according to claim 1, characterized in that: In step S5, 200 mL of anhydrous ethanol is added; the soaking time is 1 hour.

7. The method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant according to claim 1, characterized in that: In step S6, the mass percentage concentration of the surfactant coconut oil diethanolamide in the bifid interpenetrating network hydrogel dust suppressant is 0.1%-0.2%.

8. A method for preparing a dual-fiber interpenetrating network hydrogel dust suppressant according to any one of claims 1-7.

9. The application of the dual-fiber interpenetrating network hydrogel dust suppressant as described in claim 8 in ecological dust suppression in open-pit mines.

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