A dust suppressant of kgmp-eicp cooperation, preparation method and application

Abstract

The patent application discloses a KGMP-EICP synergistic dust suppressant, a preparation method and application. The KGMP-EICP synergistic dust suppressant comprises konjac glucomannan-acrylic acid graft copolymer KGMP, cementing liquid and urease. The addition amount of the konjac glucomannan-acrylic acid graft copolymer KGMP is 2-3.5 mg / mL relative to the total volume of the cementing liquid and the urease. The volume ratio of the urease to the cementing liquid is 1:0.5-1:2. The KGMP-EICP synergistic dust suppressant can form a uniform and dense solidified layer on the surface of soil, effectively improves the wind erosion resistance, the hardness of the solidified layer and the water retention performance, maintains good environmental compatibility, and finally realizes the suppression and solidification of soil dust.

Description

Technical Field

[0001] This invention relates to the field of environmental protection materials technology, specifically to a KGMP-EICP synergistic dust suppressant, its preparation method, and its application. Background Technology

[0002] Currently, common dust control methods mainly include water spraying, covering with dust nets, and using chemical dust suppressants. However, water spraying consumes a large amount of water, resulting in high costs, and its dust suppression effect is limited; dust nets have limited blocking effect, are easily damaged, and pose a risk of plastic pollution; traditional chemical dust suppressants have potential ecotoxicity, soil salinization risks, and poor biodegradability, which restrict their application in environmentally sensitive or green construction scenarios. Therefore, developing high-performance, durable, and environmentally friendly construction dust control technologies is crucial for protecting public health, promoting engineering construction, and maintaining the ecosystem.

[0003] In recent years, enzyme-induced carbonate precipitation technology for soil stabilization and dust suppression has attracted much attention due to its environmental friendliness and long-term product stability. This technology utilizes exogenous urease to catalyze the decomposition of urea to generate CO3. 2- When combined with ammonium ions and calcium ions, calcium carbonate precipitates form between soil particles and on the soil surface, cementing the particles and enhancing the surface layer's resistance to wind erosion. However, direct spraying of EICP solution for dust control still faces challenges: weak initial adhesion leads to a slightly delayed dust suppression effect; at the same time, the uniformity of the mineralization process, precipitation efficiency, and insufficient nucleation sites limit its dust suppression effect to some extent.

[0004] To overcome the aforementioned bottlenecks, scholars have attempted to introduce additives into the EICP system to improve its performance. Existing research results include: Liu et al. used chitosan in conjunction with EICP technology to improve the wind erosion resistance of red mud, increasing its critical breaking wind velocity from 5.8 m / s to 8.2 m / s, exhibiting superior durability and stability. Prabhakar and Annadurai R significantly improved the unconfined compressive strength of natural sand by combining synthetic polymer PVA with EICP technology, increasing it by approximately 13 times for beach sand and 10 times for river sand, effectively overcoming the softening defects of single PVA materials under heat curing. Zhang et al. used lignin in conjunction with EICP to increase the strength of silt in the floodplains of the Yellow River, finding that lignin provides sites for the mineralization process; adding 5% lignin increased the unconfined compressive strength by 5 times, cohesion by 10 times, and the internal friction angle by 3 times. Wang et al. found that chitosan in conjunction with EICP technology can improve Cu... 2+ and Pb 2+The high fixation rate indicates the potential for remediation of polluted water bodies. Although domestic and foreign scholars have made some progress in the research on additives used in EICP processes, current research mainly focuses on solidifying sand and silt and adsorbing heavy metals, with less research on suppressing soil dust caused by engineering construction activities. At the same time, the insufficient performance of most additives leads to large dosages and high costs. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a KGMP-EICP synergistic dust suppressant and its preparation method. The KGMP-EICP synergistic dust suppressant of this invention can form a uniform and dense solidified layer on the soil surface, effectively improving wind erosion resistance, solidified layer hardness and water retention performance, while maintaining good environmental compatibility, and finally achieving the suppression and solidification of soil dust.

[0006] The technical solution adopted in this invention is as follows:

[0007] A KGMP-EICP synergistic dust suppressant comprises: konjac glucomannan-acrylic acid graft copolymer KGMP, a binding liquid, and urease. The amount of konjac glucomannan-acrylic acid graft copolymer KGMP added is 2-3.5 mg / mL relative to the total volume of the binding liquid and urease, and the volume ratio of urease to binding liquid is 1:0.5-1:2.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0009] This invention uses konjac glucomannan-acrylic acid graft copolymer KGMP as an additive, in conjunction with EICP technology to suppress soil dust. It can form a uniform and dense solidified layer on the soil surface, effectively improving wind erosion resistance, solidified layer hardness and water retention performance, while maintaining good environmental compatibility, and ultimately achieving the suppression and solidification of soil dust.

[0010] 1. Under the catalysis of urease, urea undergoes a hydrolysis reaction, producing NH4. + and CO3 2- This provides the necessary CO3 for calcium carbonate precipitation. 2- At this stage, the konjac glucomannan-acrylic acid graft copolymer KGMP, with its excellent adhesion, can encapsulate and bind soil particles, forming a continuous protective film that effectively buffers external impacts and suppresses the initial dust emission.

[0011] 2. During the mineralization reaction stage, after adding konjac glucomannan-acrylic acid graft copolymer KGMP, its polymer chains adsorb Ca from the solution. 2+ This will release free Ca 2+ It is enriched and anchored around the KGMP molecular chains. When CO3 in the solution...2- Diffusion to these fixed Ca 2+ When nearby, due to Ca 2+ The migration ability of CO3 is limited by the KGMP of konjac glucomannan-acrylic acid graft copolymer, therefore 2- There will be a longer time with Ca 2+ The formation of stable contact ion pairs facilitates the formation of stable ion pairs and induces heterogeneous nucleation. This process effectively guides the precipitation of calcium carbonate crystals on the surface of konjac glucomannan-acrylic acid graft copolymer KGMP fibers, avoiding the random distribution of calcium carbonate crystals, resulting in more stable calcium carbonate crystal nuclei with stronger bonding.

[0012] 3. Calcium carbonate crystals regulated by KGMP in the konjac glucomannan-acrylic acid graft copolymer interweave with the three-dimensional gel network of the KGMP-regulated konjac glucomannan-acrylic acid graft copolymer to form a continuous and dense structure. The uniform size of the calcium carbonate crystals effectively fills the interparticle pores, significantly enhancing surface density and structural stability. Ultimately, a uniform and dense solidified layer is formed on the soil surface, improving wind erosion resistance, solidified layer hardness, and water retention, while maintaining good environmental compatibility, thus achieving the suppression and solidification of soil dust.

[0013] In a preferred embodiment of the present invention, the konjac glucomannan-acrylic acid graft copolymer KGMP is prepared by the following method:

[0014] (1) Add konjac glucomannan (KGM) to the reaction vessel, then add acrylic acid (AA), and stir at room temperature for 25-40 minutes;

[0015] (2) Heat to 55-65℃, add potassium persulfate (KPS) and N,N-methylenebisacrylamide (MBA) to initiate the polymerization reaction, and continue stirring for 2.5-3.5 hours;

[0016] (3) After completion, cool and filter, wash with anhydrous ethanol, filter and collect, and finally dry to constant weight to obtain konjac glucomannan-acrylic acid graft copolymer KGMP.

[0017] This method achieves efficient grafting of acrylic acid (AA) onto the Konjac glucomannan (KGM) backbone. Potassium persulfate (KPS) acts as an initiator to generate free radical active sites, and N,N-methylenebisacrylamide (MBA) acts as a crosslinking agent to form a three-dimensional network structure. This controllable free radical grafting polymerization allows KGMP to combine the natural polysaccharide backbone characteristics of KGM with the strong hydrophilicity and metal chelating ability of polyacrylic acid, ensuring the stability of the polymer chain during EICP mineralization and enabling it to continuously exert its Ca2+ content. 2+Enrichment anchoring and heterogeneous nucleation induction ensure the directional growth of calcium carbonate crystals on the KGMP fiber surface, forming a denser and more stable cured layer structure. Furthermore, anhydrous ethanol washing-filtration-drying effectively removes unreacted acrylic monomers, residual initiators, and crosslinking agents, significantly reducing the biotoxicity and environmental risks of the dust suppressant. This also ensures the purity of the final konjac glucomannan-acrylic acid graft copolymer (KGMP), enabling it to exert excellent binding-mineralization synergistic effects in soil dust suppression.

[0018] As a preferred embodiment of the present invention, for every 3.5g of konjac glucomannan (KGM), the corresponding amounts of potassium persulfate (KPS), N,N-methylenebisacrylamide (MBA), and acrylic acid (AA) are 0.134g, 0.042g, and 45mL respectively.

[0019] In this scheme, using the above ratio, the synthesized konjac glucomannan-acrylic acid graft copolymer KGMP exhibits excellent viscosity and water retention properties. On the one hand, KGMP has a better ability to bind and encapsulate soil particles, effectively buffering external impacts and suppressing the initial dust rise. On the other hand, it ensures the moist state of the solidified layer in a dry environment, delays water evaporation, and maintains urease catalytic activity, providing a stable environment for the continuous EICP mineralization reaction.

[0020] In a preferred embodiment of the present invention, the konjac glucomannan (KGM) has a purification degree of 95% or higher. This method achieves a KGM purity of 95% or higher, significantly improving the efficiency and product uniformity of the graft copolymerization reaction. High-purity KGM reduces the interference of impurities such as hemicellulose and proteins on the free radical initiation system, resulting in a more uniform and controllable distribution of AA (acrylic acid) grafting sites on the KGM backbone. This leads to the preparation of KGMKGMP with a narrow molecular weight distribution and regular branched structure, exhibiting more stable Ca²⁺ content. 2+ Chelating ability and superior 3D network forming effect.

[0021] In a preferred embodiment of the present invention, the cementing solution is composed of calcium chloride and urea in the form of a mixed solution, both with a molar concentration of 0.5-0.8 mol / L.

[0022] In this scheme, the above-mentioned cementing solution is used, and the KGMP molecular chains bind to Ca. 2+ The chelation effect of calcium carbonate and the controlled-release carbon of urea are more balanced, allowing calcium carbonate to be uniformly deposited and densely filled on the surface of soil particles, forming a stable, hard, and durable surface solidification layer, which improves the wind erosion resistance and long-term solidification effect of the dust suppressant.

[0023] In a preferred embodiment of the present invention, the urease is canavagin urease extracted from sword beans. In this method, canavagin urease exhibits high activity, strong specificity, and a wide pH adaptability range. Using canavagin urease extracted from sword beans as a biocatalyst ensures the high efficiency and stability of the urea hydrolysis reaction.

[0024] In a preferred embodiment of the present invention, the amount of konjac glucomannan-acrylic acid graft copolymer KGMP added is 3 mg / mL, and the volume ratio of urease to cementing solution is 1:1.

[0025] In this study, the applicant discovered that when the concentration of konjac glucomannan-acrylic acid graft copolymer KGMP is less than or equal to 3 mg / mL, KGMP can provide more uniform nucleation sites for the mineralization process, thereby regulating crystal growth and synergistically improving precipitation efficiency. However, when the concentration exceeds 3 mg / mL, the system viscosity increases dramatically, hindering ion diffusion and resulting in a decrease in precipitation rate. The volume ratio of urease to cementing solution is 1:1 to ensure that the urea hydrolysis rate is consistent with that of Ca. 2+ Synchronized supply rates enable calcium carbonate crystals to grow and precipitate continuously and uniformly on the surface of konjac glucomannan-acrylic acid graft copolymer KGMP fibers.

[0026] This invention also provides a method for preparing a KGMP-EICP synergistic dust suppressant, comprising the following steps:

[0027] (1) Add the cementing liquid to the container at room temperature, then add the konjac glucomannan-acrylic acid graft copolymer KGMP to the container, mix evenly and use it as the first dust suppression component;

[0028] (2) Urease solution is the second dust-suppressing component;

[0029] When using, first spray the first dust suppression component, then spray the second dust suppression component.

[0030] In this scheme, KGMP-cementing solution is used as the first dust suppression component, and urease solution is used as the second dust suppression component. KGMP fully swells and extends in the cementing solution, and Ca is pre-anchored through the active sites of carboxyl and hydroxyl groups on the molecular chain. 2+ It can form a uniform ion-trapping network covering the soil surface; the sprayed urease solution immediately triggers the urea hydrolysis reaction at the interface, causing CO3 to... 2- In the pre-fixed Ca 2+The surrounding area generates and triggers heterogeneous nucleation. This stepwise application method effectively avoids the inactivation of enzyme active sites due to polymer encapsulation caused by mixing KGMP and urease, as well as premature mineralization reaction. The reaction can be flexibly controlled on the construction site. Ultimately, the KGMP three-dimensional gel network and calcium carbonate intertwine and grow in situ on the soil surface, forming a dense, continuous, and firmly bonded solidified layer, which significantly improves the dust suppressant's wind erosion resistance, curing hardness, and long-term durability.

[0031] The above-mentioned KGMP-EICP synergistic dust suppressant application involves uniformly spraying the first dust suppressant component—a mixture of cementitious liquid and konjac glucomannan-acrylic acid graft copolymer KGMP—onto the dust-generating building area, followed by spraying the second dust suppressant component—urease solution—at a density of 1.5-2.5 L / m³. 2 .

[0032] In this scheme, the spraying density ensures that the KGMP-EICP mixture forms a continuous liquid film layer of suitable thickness on the soil surface. When the density is less than 1.5L / m², the liquid film is difficult to completely cover the rough surface, resulting in discontinuous defects in the cured layer and a significant decrease in wind erosion resistance. On the other hand, when the density is greater than 2.5L / m², the surface liquid film becomes too thick, which not only prolongs the curing time but also increases the construction cost. Attached Figure Description

[0033] Figure 1 It is an interactive analysis of viscosity response values;

[0034] Figure 2 It is an interactive analysis of the anti-evaporation response values;

[0035] Figure 3 These are the Fourier infrared spectra of KGM and KGMP;

[0036] Figure 4 It is the precipitation rate of calcium carbonate when KGMP is added;

[0037] Figure 5 The wind erosion resistance of soil dust samples treated with KGMP-EICP and EICP;

[0038] Figure 6 It is the hardness of the solidified layer of soil dust samples treated by KGMP-EICP and EICP.

[0039] Figure 7 It refers to the water retention rate of soil samples treated with KGMP-EICP and EICP.

[0040] Figure 8 It is the degradation rate of the solidified layer in the soil environment after 14 days;

[0041] Figure 9These are SEM images of soil dust samples: (a) KGMP-EICP processed sample at 400x magnification; (b) EICP processed sample at 400x magnification; (c) KGMP-EICP processed sample at 10000x magnification; (d) EICP processed sample at 10000x magnification.

[0042] Figure 10 These are the XRD patterns of soil dust samples treated with KGMP-EICP and EICP.

[0043] Figure 11 FTIR spectra of soil dust samples treated with EICP and KGMP-EICP;

[0044] Figure 12 Mean square displacement of calcium ions;

[0045] Figure 13 It is CO3 2- and Ca 2+ The radial distribution function;

[0046] Figure 14 The binding energy between calcium ions and carbonate ions;

[0047] Figure 15 TSP concentrations of KGMP-EICP and EICP treatments on days 1, 7, 14, and 30: (a) Day 1; (b) Day 7; (c) Day 14; (a) Day 30. Detailed Implementation

[0048] Typical embodiments embodying the features and advantages of the present invention will be specifically described in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations herein are for illustrative purposes only and not intended to limit the present invention.

[0049] In the following examples, KGM was purified to 95% and purchased from Shaanxi Evergreen Biotechnology Co., Ltd. (Xi'an, China). Potassium persulfate (KPS) was the initiator, produced by Xilong Scientific Co., Ltd. (Shantou, China), and was of analytical grade. N,N-methylenebisacrylamide (MBA), used as a cross-linking agent, was purchased from Xi'an Tianmao Baoding Biotechnology Co., Ltd. (Xi'an, China), and was also of analytical grade. Monomer AA was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. (Shanghai, China).

[0050] The cementing solution consisted of a mixed solution of calcium chloride and urea, both with a molar concentration of 0.6 mol / L. The calcium chloride was supplied by Sinopharm Chemical Reagent Co., Ltd. (Ningbo, China), and the urea was obtained from Hunan Bickman Biotechnology Co., Ltd. (Changde, China). The urease used was canavagin urease extracted from sword beans.

[0051] Example 1

[0052] This embodiment discloses a KGMP-EICP synergistic dust suppressant, comprising konjac glucomannan-acrylic acid graft copolymer KGMP, a binding liquid, and urease. The amount of konjac glucomannan-acrylic acid graft copolymer KGMP added is 3 mg / mL relative to the total volume of the binding liquid and urease, and the volume ratio of urease to binding liquid is 1:1.

[0053] The konjac glucomannan-acrylic acid graft copolymer KGMP was prepared using the following method:

[0054] (1) Add konjac glucomannan KGM to the reaction vessel, then add acrylic acid AA, and stir for 30 minutes at room temperature in a heat-collecting constant temperature magnetic stirrer to allow konjac glucomannan KGM to fully swell in acrylic acid AA;

[0055] (2) Heat to 60°C, add potassium persulfate (KPS) and N,N-methylenebisacrylamide (MBA) to initiate the polymerization reaction, and continue stirring for 3 hours;

[0056] (3) After completion, cool and filter, wash with anhydrous ethanol, filter and collect, and finally dry to constant weight to obtain konjac glucomannan-acrylic acid graft copolymer KGMP.

[0057] In the above method for preparing konjac glucomannan-acrylic acid graft copolymer KGMP, the corresponding amounts of potassium persulfate KPS (0.134g), N,N-methylenebisacrylamide MBA (0.042g), and acrylic acid AA (45mL) are used for every 3.5g of konjac glucomannan KGM.

[0058] The preparation method of the KGMP-EICP synergistic dust suppressant in this embodiment includes the following steps:

[0059] (1) Add the cementing liquid to the container at room temperature, then add the konjac glucomannan-acrylic acid graft copolymer KGMP to the container, mix evenly and use it as the first dust suppression component;

[0060] (2) Urease solution is the second dust-suppressing component;

[0061] When using, first spray the first dust suppression component, then spray the second dust suppression component.

[0062] In this invention, relative to the total volume of the cementing solution and urease, the amount of konjac glucomannan-acrylic acid graft copolymer KGMP added has a significant impact on the calcium carbonate precipitation rate during the EICP process, ultimately affecting the synergistic dust suppression of KGMP-EICP. Examples 1-4 in the table below are examples with different amounts of KGMP added, and other conditions are the same as in Example 1 above.

[0063]

[0064] Response surface methodology for optimizing grafting process and optimal ratio

[0065] This invention uses the Box-Behnken model in DesignExpert 13 for response surface methodology design. KPS, MBA, and AA, the three raw materials in the graft copolymerization reaction, are used as factors, and the viscosity and water retention rate of KGMP aqueous solution at a concentration of 0.3 wt.% are used as response values. A three-factor, two-level experimental design was employed, with a total of 17 experimental points, including 5 center points. Tests were conducted on the 17 sets of experiments in the response surface methodology table. Finally, both response values ​​were optimized using a "the larger the better" criterion, determining the optimal ratio of KPS, MBA, and AA components in the graft copolymerization process. The powder prepared using the optimal ratio was used in subsequent examples. The codes and levels of each factor in the response surface methodology design are shown in Table 1.

[0066] Table 1 Factors and levels of RSM

[0067]

[0068] (1) Testing of viscosity response value

[0069] Prepare 800 mL of 0.3 wt.% aqueous solution using the KGMP from each experimental group. After thorough stirring at room temperature, allow to stand for 1 hour, and then measure the viscosity using an NDJ-5S rotational viscometer. Take the average of three measurements as the result.

[0070] (2) Test of evaporation resistance response value

[0071] The evaporation resistance response value was tested using a round glass petri dish with a diameter of 75 mm. First, the cleaned glass petri dish was dried. Then, 20 g of pre-dried soil dust sample was weighed, evenly spread in the petri dish, and then sprayed with 10 ml of KGMP solution. Next, the petri dish was placed in an electric drying oven preheated to 60°C and dried for 3 hours before being weighed. Finally, the evaporation resistance rate was obtained using formula (1).

[0072]

[0073] In the formula: R is the soil water retention rate (%), m2 is the weight after drying for 3 hours (g), m1 is the weight before spraying (g), and m is the weight of the sprayed solution (g).

[0074] Table 2 lists the results of a series of experiments using the response surface methodology. Analysis shows that the relationship between the responses of viscosity and water retention rate and the three factors KPS, MBA, and AA can be described by a quadratic polynomial model. The data in Table 2 were fitted and subjected to analysis of variance using the polynomial regression function in response surface methodology. This led to the construction of a model showing the relationship between the two responses of viscosity and water retention rate and the three factors KPS, MBA, and AA. Tables 3 and 4 respectively illustrate the established quadratic polynomial regression equation and the corresponding model error statistical analysis.

[0075] Table 4 shows that the p-values ​​of both models are smaller than 0.0001, indicating that the input variables have a highly significant impact on the models. Meanwhile, the p-values ​​of the residuals for each model are all much greater than 0.05, suggesting that the experimental errors have little impact on the response values ​​of the two models, indicating that the model construction is reasonable. The coefficients of determination (R²) for each model all exceed 0.95, and the predictive coefficients of determination for both models are... ) and the adjusted coefficient of determination R² The differences between the two models are all less than 0.2, which confirms the high reliability of the model predictions and the excellent regression performance. Furthermore, the signal-to-noise ratio (AP) of both models is greater than 4, and the percentage of variation (CV%) is less than 10%, indicating that the data variation is within an acceptable range and the impact of outliers is limited. In summary, all established models demonstrate good goodness of fit.

[0076] Table 2 RSM results

[0077]

[0078] Table 3 Quadratic polynomial regression equation of RSM

[0079]

[0080] Table 4 Variance analysis of response

[0081]

[0082] The more pronounced the curvature of the response surface plot, the faster the color change, and the flatter the elliptical shape of the contour lines, the stronger the interaction between the two factors in the response surface. Conversely, the less pronounced the curvature, the slower the color change, and the more circular the contour lines, the weaker the interaction between the two factors in the response surface. Figure 1It can be seen that the pairwise interactions among KPS, MBA, and AA have a significant impact on the viscosity of KGMP. The interaction between KPS and AA has the most significant effect on KGMP viscosity, while the interaction between MBA and AA has the least impact. This indicates that maintaining KPS and AA at low and high levels, respectively, can increase the viscosity of KGMP.

[0083] Similarly, from Figure 2 It can be seen that the response surface curve between KPS and MBA is the most pronounced, the color changes the fastest, and the contour lines are the flattest ellipses. This indicates that the interaction between KPS and MBA has the greatest impact on the evaporation resistance of KGMP, while the interaction between MBA and AA has the least impact. Therefore, this analysis suggests that maintaining KPS at a moderate level and MBA at a high level can maximize the evaporation resistance of KGMP.

[0084] When performing optimal formulation analysis using the Box-Behnken experimental design in Design Expert 13, viscosity and water retention were both optimized to maximize these objectives, ensuring that KGMP exhibits excellent bonding and water-holding properties. The optimal formulation determined by the software analysis was: KPS 0.134g, MBA 0.042g, and AA 45ml. The model predicted a solution viscosity of 190.97 mPa·s and a water retention rate of 63.47% at this ratio. The solution was prepared strictly according to this formulation, and its viscosity and water retention rate were measured. Three parallel measurements were performed for verification, and the average value was used to calculate the relative error with the predicted value (see Table 5). The data in Table 5 show that the actual measured values ​​of the above two performance indicators differ only slightly from the model predictions, fully demonstrating its rationality and reliability.

[0085] Table 5 Validation of optimal formulation

[0086]

[0087] KGMP preparation was successfully verified.

[0088] The FTIR spectra of KGM and KGMP are as follows: Figure 3 As shown. For the infrared spectrum of KGM, at 3440 cm⁻¹ -1 A stretching vibration peak of the hydroxyl group (-OH) appears at 2927 cm⁻¹. -1 The peak at 1153 cm⁻¹ represents the antisymmetric stretching vibration of the aliphatic methylene group (-CH₂-). -1 and 1025cm -1 The peak at this location represents the stretching vibrations inside and outside the CO asymmetric ring. For the KGMP infrared spectrum, it appears at 3440 cm⁻¹. -1The stretching vibration peak of the hydroxyl group (-OH) at 2927 cm⁻¹ -1 The aliphatic methylene (-CH2-) antisymmetric stretching vibration peak at 1153 cm⁻¹ -1 The stretching vibration peak of CO is shared with that of KGM. Additionally, the peak at 1734 cm⁻¹... -1 The peak corresponds to the stretching vibration at C=O. For 1562 cm⁻¹... -1 1406cm -1 -COO appears at the location - The stretching vibration peak is consistent with the characteristic absorption peak of polyacrylic acid. Furthermore, the peak at 1025 cm⁻¹ in KGM is also consistent. -1 The CO vibration peak appearing at this location appears at 1057 cm⁻¹ in the KGMP infrared spectrum. -1 At this point, KGMP contains a large amount of -OH and -COO. - The presence of hydrophilic groups indicates that konjac glucomannan (KGM) and acrylic acid (AA) underwent a graft copolymerization reaction.

[0089] Experiment on the effect of KGMP addition on calcium carbonate precipitation rate

[0090] The KGMP prepared according to the optimal ratio of this invention was used to investigate the effect of adding different concentrations of KGMP on the precipitation rate of calcium carbonate through single-factor experiments. Precipitation experiments were conducted in round borosilicate glass petri dishes to analyze the precipitation rate during the process. First, the mass of the petri dish was weighed and recorded. Then, 20 mL of gel solution was added to it. Next, KGMP powder with a concentration range of 2-4 mg / mL was added in increments of 0.5 mg / mL. Finally, 20 mL of urease solution was added to the petri dish and reacted for 24 h. After the reaction, the calcium carbonate in the petri dish was washed clean. Then, the petri dish was dried at 60 °C to constant weight. The precipitation rate of calcium carbonate was calculated by equation (2).

[0091]

[0092] In the formula, The formula refers to the precipitation rate (%), m represents the actual mass of calcium carbonate produced (g), the concentration of the cementing solution (mol / L) is represented by the symbol C, V represents the volume of the cementing solution (L), and M means the molar mass of calcium carbonate (100.087 g / mol).

[0093] Figure 4The results show the calcium carbonate precipitation rate during EICP at different KGMP concentrations corresponding to Examples 1-5, and a comparison with pure EICP. It can be seen that the KGMP concentrations corresponding to Examples 1-5 have a higher calcium carbonate precipitation rate during EICP. As the KGMP concentration increases from 2 mg / mL to 4 mg / mL, the precipitation rate first increases and then decreases, reaching a peak of 90.42% at a KGMP concentration of 3 mg / mL, which is 11.09% higher than pure EICP; however, at 3.5 mg / mL and 4 mg / mL, the precipitation rate shows a continuous decreasing trend. At concentrations less than or equal to 3 mg / mL, KGMP can provide more uniform nucleation sites for the mineralization process, playing a role in regulating crystal growth, and these factors synergistically improve precipitation efficiency. However, when the concentration is greater than 3 mg / mL, the system viscosity increases sharply, hindering ion diffusion and causing a decrease in precipitation rate. Therefore, the preferred KGMP concentration in this invention is 2-3.5 mg / mL, more preferably 2.5-3.5 mg / mL, and optimally 3.5 mg / mL.

[0094] I. Performance Experiment

[0095] The KGMP-EICP synergistic dust suppressant of Example 1 of this invention was subjected to wind erosion resistance test, cured layer hardness test, water retention test, and degradation test, and was compared with pure EICP solution. The experimental process and results are as follows.

[0096] (1) Wind erosion resistance test

[0097] Two 200g soil dust samples were placed in two separate iron pans and dried in an electric heating drying oven. Subsequently, according to standard DB34 / T 3804–2021, 115ml of KGMP-EICP solution and EICP solution were evenly sprayed separately (spraying density approximately 2L / m³). 2 After drying at room temperature, the sample was weighed. A blower was started at a distance of 90 cm from the iron pan, and the surface of the soil dust sample was continuously abraded at a wind speed of 12 m / s for 2 hours. The weight of the iron pan was measured every 20 minutes and recorded as m. i The wind erosion resistance rate is calculated according to formula (3).

[0098]

[0099] In the formula, w f Indicates wind erosion resistance rate (%), m i The value is the mass (g) of the iron disc every 20 minutes during the erosion process, and M represents the initial mass (g) of the iron disc after treatment.

[0100] Figure 5The study demonstrates the changing trends of wind erosion resistance of soil dust samples treated with EICP and KGMP-EICP over time. It shows that the soil's wind erosion resistance weakens with increasing treatment duration. After 2 hours of continuous erosion, the soil sample treated with KGMP-EICP dust suppressant lost only 1.27% of its mass, while the soil sample treated with pure EICP lost as much as 11.39%. The KGMP-EICP dust suppressant group showed a 10.12% higher wind erosion resistance than the EICP group after 2 hours. The wind erosion resistance experimental data indicate that the addition of KGMP enhances the wind erosion resistance of EICP, maintaining structural stability even under prolonged wind erosion.

[0101] (2) Hardness test of cured layer

[0102] Two dried soil dust samples were placed in iron pans measuring 29.5cm × 19.5cm × 2cm, and 115ml of KGMP-EICP and EICP solutions were sprayed evenly onto each sample, respectively. After the samples were allowed to air dry at room temperature, the hardness of the cured layer on the surface was measured using an LX-A digital hardness tester. Five locations were randomly selected on the surface for testing, and the final hardness result was determined by the average of the five measurements.

[0103] For dust suppression and solidification layers, higher hardness directly translates to stronger load-bearing capacity and resistance to external mechanical damage. Both KGMP-EICP and EICP treatments resulted in the formation of solidification layers on the surface of soil dust samples. Figure 6 The results clearly show that the hardness of the solidified layer in the KGMP-EICP group is significantly better than that in the soil dust sample treated with EICP. Specifically, the average hardness of the EICP-KGMP group reached 63.18 HA, while that of the EICP group was 55.9 HA. This increase in hardness may be attributed to the synergistic effect of KGMP and calcium carbonate, which creates a denser and more uniform calcium carbonate crystalline structure.

[0104] (3) Water retention test

[0105] First, a clean, round aluminum box with a diameter of 60mm and a height of 60mm was placed in an electrically heated drying oven to dry. After cooling, its mass was weighed and recorded as m0. Then, referring to standard NY / T 1121.3-2006, 10g of dried soil was weighed and evenly spread inside the aluminum box. Next, 6ml of EICP solution and KGMP-EICP solution were quantitatively sprayed (the spraying rate was approximately 2L / m). 2 The aluminum box was weighed as a whole, and the mass was recorded as m1. Then, the lid was placed on the aluminum box at an angle and put into an electric heating drying oven preheated to 105°C for 6 hours. The aluminum box was weighed every 1 hour. Finally, the water retention rate was calculated according to equation (4).

[0106]

[0107] In the formula, m0, m1, These refer to the initial mass of the aluminum box, the mass after processing, and the corresponding mass measured hourly during the drying process, respectively.

[0108] The water retention rate directly reflects the dust suppressant's ability to retain soil moisture. Figure 7 As can be seen, compared to the KGMP-EICP solution, the water retention rate of the EICP solution decreased more rapidly over time. After 6 hours, the water retention rate of the KGMP-EICP-treated sample was 44.2%, which was 11.85% higher than that of the EICP-treated sample. This means that under the same high-temperature drying environment, KGMP-EICP can retain moisture in the soil for a longer period of time.

[0109] (4) Degradation experiment

[0110] Aluminum foil was placed in two glass petri dishes, and EICP solution and KGMP-EICP solution were added to the petri dishes respectively. The dishes were left to stand until the reaction was complete. Then, the dishes were dried in an electric heating drying oven at 60°C until constant weight. A small piece was cut off and placed on aluminum foil, and its mass was weighed and recorded as m1. Then, the pieces were placed in an 80-mesh nylon bag and buried underground for a comparative test. The samples were taken out after 14 days of burial and then dried until constant weight was achieved. The mass of the degraded samples was weighed and recorded as m2. The degradation rate was defined in this study as the quantitative result determined according to equation (5).

[0111]

[0112] In the formula, m1 represents the mass before degradation, and m2 represents the mass after degradation.

[0113] according to Figure 8 As shown, under natural conditions, the solidified layers exhibited different degradation rates in the soil environment. During the 14-day degradation experiment, the degradation rate of the solidified layer generated by EICP reached 9.41%, while the degradation rate of KGMP-EICP was 10.54%. After 14 days, the surface of the EICP-treated sample was dry, while the surface of the KGMP-EICP-treated sample was significantly more moist. Analysis suggests that the slight increase in the degradation rate of soil dust samples treated with KGMP-EICP may be attributed to the degradation of the introduced KGMP, confirming its good environmental absorbability.

[0114] II. Microstructure Characterization

[0115] The microstructure of soil dust samples treated with the KGMP-EICP synergistic dust suppressant of Example 1 of this invention was characterized, and compared with soil dust samples treated with pure EICP solution. The experimental process and results are as follows.

[0116] (1) Scanning electron microscope (SEM)

[0117] Gold sputtering was performed on the sample surface to improve conductivity and avoid imaging artifacts caused by charge accumulation. Subsequently, soil dust samples treated with KGMP-EICP or EICP were subjected to morphological analysis under vacuum conditions using a Gemini SEM300 scanning electron microscope in secondary electron mode at a magnification range of 400 to 10,000 times to analyze the differences in their surface structure.

[0118] SEM images of soil dust samples processed by KGMP-EICP and EICP respectively are shown below. Figure 9 As shown. In Figure 9 In step a, after KGMP-EICP treatment, calcium carbonate crystals intertwine with the KGMP three-dimensional gel network, resulting in uniform crystal size and no large-sized crystal accumulation. Meanwhile... Figure 9 In sample b, the soil dust sample treated with EICP showed a discrete particle distribution and significant differences in crystal size, with obvious local accumulation voids. In contrast, the solidified layer treated with KGMP-EICP exhibited a more uniform distribution of calcium carbonate particles, which filled the gaps between soil particles and enhanced wind erosion resistance. Figure 9 c clearly shows that the needle-like KGMP organic fibers extend radially from the center, with a significant fiber network structure and calcium carbonate tightly attached to the fiber surface. Figure 9 In sample d, the intercrystalline bonds of calcium carbonate are weak and easily broken, and there are large pores. (Comparison) Figure 9 c and Figure 9 As can be seen from d, after KGMP-EICP treatment, the fiber network of KGMP can provide more nucleation sites for the mineralization process, thereby filling the pores between particles and significantly improving the dust suppression effect.

[0119] (2) X-ray diffraction (XRD)

[0120] The effects of KGMP-EICP or EICP treatment on soil dust samples were analyzed using a SmartLab SE X-ray diffractometer to identify material components and confirm the presence of specific phases. A copper target was used, with a diffraction angle scanning range of 5° to 90° and a scanning speed of 2° / min.

[0121] Figure 10The diffraction patterns are those of samples treated with EICP-KGMP and EICP, respectively. MDI Jade 9.0 software was used to retrieve and identify the phases using the International Data Center for Diffraction (ICDD-PDF) standard database. A not-so-sharp diffraction peak appeared near 2θ=20°, this broad peak being attributed to KGMP. The main peak positions at 23.05°, 29.41°, 35.97°, 39.4°, 43.17°, 47.52°, 48.51°, and 57.4° all matched the calcite-type CaCO3 standard card (PDF#99-000-0548) in the ICDD-PDF standard database, proving that the generated calcium carbonate crystal type conforms to the calcite structural characteristics.

[0122] (3) Fourier transform infrared spectroscopy (FTIR)

[0123] The sample was in powder form, which was mixed with potassium bromide and ground evenly to prepare test pieces. The temperature was between 4000 and 4000 cm⁻¹. -1 The range was scanned using a Nicolet iS20 Fourier transform infrared spectrometer, and the data was exported in absorbance mode.

[0124] Figure 11 Middle, 3440cm -1 The peak at 3622 cm⁻¹ is the stretching vibration peak of the hydroxyl group, while the peak at 3622 cm⁻¹ in the KGMP-EICP infrared spectrum is... -1 A new peak appeared, attributed to non-hydrogen-bonded hydroxyl groups, likely due to steric hindrance after AA grafting onto konjac glucomannan. KGMP contains COOH, and the KGMP-EICP group peaked at 1643 cm⁻¹. -1 The absorption peak at 1629 cm⁻¹ is due to the stretching of the C=O bond in COOH. (EICP treated group) -1 The absorption peak at 1420 cm⁻¹ also belongs to COOH. -1 The absorption peak at [value] is consistent with the characteristics of the CO bond in CaCO3. The stretching vibration frequency of CO appears at 1278.92 cm⁻¹. -1 Up to 1026.46cm -1 Within the range, therefore the KGMP-EICP treatment group is 1026 cm⁻¹. -1 Treatment group and EICP treatment group 1045cm -1 The absorption peaks at 876 cm⁻¹ are all caused by CO stretching vibrations. In the EICP-treated group, the peak at 876 cm⁻¹ is... -1 Location, 712cm -1 In the KGMP-EICP treatment group, 710cm -1 The absorption peak at that location matches CO3. 2- The characteristics, and 793 cm in the KGMP-EICP treatment group -1The same applies here. The positions of some absorption peaks changed slightly, possibly due to the steric hindrance effect caused by the addition of KGMP.

[0125] (4) Molecular dynamics simulation

[0126] Molecular dynamics simulations were performed using Materials Studio 2023 software. First, molecular models of KGMP and water molecules, and ionic models of carbonate and calcium ions were constructed using the Sketch tool. Then, based on the actual amounts of raw materials, the quantities of each model in the two systems were proportionally calculated: 1000 water molecules, 11 calcium ions, and one system also containing one KGMP molecule. Since the number of carbonate ions produced by urea hydrolysis could not be calculated, it was set to be the same as the number of calcium ions. This simplifies the calculation process without affecting the research objective of exploring the regulatory mechanism of KGMP on calcium carbonate nucleation. Then, two reaction systems were constructed using the Amorphous Cell module. The solution cell size of the KGMP-EICP system was 32.22 Å * 32.22 Å * 32.22 Å, and that of the EICP system was 31.15 Å * 31.15 Å * 31.15 Å. The molecular models and initial configurations are shown below. Figure 5 As shown.

[0127] All molecular dynamics calculations were performed in the Forcite module, using COMPASS III force field calculations. First, 10 initial solution cell configurations were constructed, and the lowest energy configuration was selected. The GeometryOptimization task in the Forcite module was used to perform 10,000 steps of geometry optimization to achieve geometric equilibrium. Then, the Anneal task in the Forcite module was used to anneal the model at 300K to 500K for 5 cycles to help the system model overcome the potential barrier and search for a more stable configuration. After annealing, the lowest energy configuration was again selected, and the simulation temperature was fixed at 298K with a pressure of 1.01325 × 10⁻⁶. -4 GPa was used to perform molecular dynamics simulations on the model for 500 ps using the Dynamics task in the NPT ensemble. The time step was set to 1 fs, the cutoff radius was 15.5 Å, and the electrostatic interactions were calculated using the Ewald summation method, while the van der Waals interactions were calculated using the Atom-based summation method.

[0128] like Figure 12The mean square displacement (MSD) and corresponding diffusion coefficients of the KGMP-EICP and EICP systems during the simulation are shown in the figure. The results indicate that the MSD curve of the KGMP-EICP system is consistently significantly lower than that of the pure EICP system. These results suggest that the addition of KGMP reduces the Ca content during the mineralization process of EICP. 2+ The significantly reduced migration ability of KGMP indicates that it can effectively adsorb calcium ions, thereby providing more nucleation sites for the mineralization process. This avoids the local aggregation of ions due to excessively rapid movement, which would eventually lead to random precipitation. It promotes the nucleation of calcium carbonate and the growth of calcium carbonate crystals, forming a more uniform calcium carbonate precipitate, improving dust suppression and the strength of the solidified layer.

[0129] Figure 13 CO3 was demonstrated 2- With Ca 2+ The radial distribution function curve between them was calculated, and the distance from Ca was... 2+ CO3 was found at a distance r. 2- The relative probability. The radial distribution function is calculated using formula (8).

[0130]

[0131] Where dN represents the number of specific particles ranging from r to r+dr from the reference particle, r represents the distance in the simulation cell, and ρ is the density.

[0132] It can be seen that the lateral coordinates of the highest peaks on both radial distribution function curves are within 3.5 Å, indicating that CO3... 2- With Ca 2+ There are very strong interactions between them. CO3 in the EICP system 2- With Ca 2+ The highest peak value of the RDF curve was 66.54. After adding KGMP, the CO3 in the KGMP-EICP system... 2- With Ca 2+ The maximum peak value of the RDF curve increased to 85.31. This significant increase indicates that, in the presence of KGMP, the free Ca in the solution... 2+ and CO3 2- The probability of direct collision and binding is significantly increased, thereby promoting CO3 production. 2- With Ca 2+ The close contact between them enhances their bonding, ultimately resulting in an increased precipitation rate of calcium carbonate crystal particles.

[0133] The larger the absolute value of the binding energy, the stronger the binding interaction between the two molecules or ions, and the more stable the complex formed. The CO3 content in the system was calculated according to formula (9). 2- and Ca 2+ The binding energy.

[0134]

[0135] In the formula, E Binding Used to represent CO3 2- and Ca 2+ The binding energy between them, E A-B CO3 2- and Ca 2+ The energy of the composite, E A The meaning is CO3 in the system 2- Energy, E B Indicating Ca in the system 2+ Energy.

[0136] CO3 was obtained through calculation. 2- and Ca 2+ The binding energy is recorded for each frame, for a total of 500 frames. The binding energy curves of the simulation process are plotted, and the average binding energy is calculated and displayed. Figure 14 In the entire 500ps simulation period, the CO3 content in the system after adding KGMP-EICP was... 2- With Ca 2+ The binding energy curves of CO3 in the KGMP-EICP system are mostly located above the EICP binding energy curves. 2- With Ca 2+ The average binding energy compared to CO3 in the EICP system 2- With Ca 2+ The average binding energy was increased by 25.43%. This means that, in the presence of KGMP, CO3... 2- With Ca 2+ A more stable and stronger interaction occurred between them, thereby increasing the amount of calcium carbonate precipitate.

[0137] III. On-site Experiment

[0138] A field experiment was conducted using the KGMP-EICP synergistic dust suppressant of Example 1 of this invention, and compared with pure EICP solution. The experimental process and results are as follows.

[0139] At a construction site, two adjacent 1m sections were selected. 2 Field experiments were conducted in the area. The dust suppression effect was evaluated by monitoring the dynamic changes in the total suspended particulate matter (TSP) concentration in the area treated with KGMP-EICP and EICP solutions on days 1, 7, 14, and 30. The actual dust suppression performance of KGMP-EICP and EICP solutions was compared and analyzed.

[0140] TSP concentration monitoring results from field experiments ( Figure 15The results clearly show that the KGMP-EICP treatment group exhibits a superior and more durable dust suppression effect compared to pure EICP solution treatment.

[0141] Analysis of intraday dynamic changes revealed that TSP concentrations exhibited regular fluctuations related to construction site activities and weather conditions, typically peaking during working hours. Notably, during these periods of greatest disturbance, the peak TSP concentrations in the KGMP-EICP group were consistently significantly lower than those in the control group. This demonstrates that the composite structure formed by KGMP-EICP possesses stronger structural integrity and can more effectively resist dust re-entrainment caused by sunlight, wind, and potential mechanical disturbances.

[0142] In the long term, the daily average TSP concentration in both treatment groups gradually increased over time, but the rate of increase was significantly slower in the KGMP-EICP group. By day 30, the daily average TSP concentration in the KGMP-EICP treatment area was 59.75 μg / m³. 3 The EICP treatment concentration was 73.42 μg / m³. 3 This represents a significant reduction of approximately 19.72%. This indicates that the introduction of KGMP enhances the durability of the cured layer.

[0143] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A KGMP-EICP synergistic dust suppressant, characterized in that, The mixture includes konjac glucomannan-acrylic acid graft copolymer KGMP, a binding solution, and urease. The amount of konjac glucomannan-acrylic acid graft copolymer KGMP added is 2-3.5 mg / mL relative to the total volume of the binding solution and urease, and the volume ratio of urease to binding solution is 1:0.5-1:

2.

2. The KGMP-EICP synergistic dust suppressant according to claim 1, characterized in that, The konjac glucomannan-acrylic acid graft copolymer KGMP was prepared by the following method: (1) Add konjac glucomannan (KGM) to the reaction vessel, then add acrylic acid (AA), and stir at room temperature for 25-40 minutes; (2) Heat to 55-65℃, add potassium persulfate (KPS) and N,N-methylenebisacrylamide (MBA) to initiate the polymerization reaction, and continue stirring for 2.5-3.5 hours; (3) After completion, cool and filter, wash with anhydrous ethanol, filter and collect, and finally dry to constant weight to obtain konjac glucomannan-acrylic acid graft copolymer KGMP.

3. The KGMP-EICP synergistic dust suppressant according to claim 2, characterized in that, For every 3.5g of konjac glucomannan (KGM), the corresponding amounts of potassium persulfate (KPS), N,N-methylenebisacrylamide (MBA), and acrylic acid (AA) are 0.134g, 0.042g, and 45mL, respectively.

4. The KGMP-EICP synergistic dust suppressant according to claim 2, characterized in that: The purification level of the konjac glucomannan (KGM) is 95% or higher.

5. The KGMP-EICP synergistic dust suppressant according to claim 2, characterized in that: The cementing solution is composed of calcium chloride and urea in a mixed solution, each with a molar concentration of 0.5-0.8 mol / L.

6. The KGMP-EICP synergistic dust suppressant according to claim 1, characterized in that: The urease is scallop urease extracted from sword beans.

7. The KGMP-EICP synergistic dust suppressant according to any one of claims 1-6, characterized in that: The amount of konjac glucomannan-acrylic acid graft copolymer KGMP added is 3 mg / mL, and the volume ratio of urease to cementing solution is 1:

1.

8. The method for preparing the KGMP-EICP synergistic dust suppressant according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Add the cementing liquid to the container at room temperature, then add the konjac glucomannan-acrylic acid graft copolymer KGMP to the container, mix evenly and use it as the first dust suppression component; (2) Urease solution is the second dust-suppressing component; When using, first spray the first dust suppression component, then spray the second dust suppression component.

9. The application of the KGMP-EICP synergistic dust suppressant according to any one of claims 1-7, characterized in that: In dusty construction areas, uniformly spray the first dust-suppressing component, a mixture of cementitious liquid and konjac glucomannan-acrylic acid graft copolymer (KGMP), followed by the second dust-suppressing component, urease solution, at a spray density of 1.5-2.5 L / m². 2 .

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