Composite snow-melting agent material and preparation method thereof

Abstract

The application discloses a composite snow-melting agent material and a preparation method thereof, and belongs to the field of environment-friendly functional materials. The method comprises the following steps: firstly, compounding activated 3A zeolite and a thiourea soft template; secondly, modifying a snow-melting main body (sodium chloride, calcium chloride and calcium magnesium acetate are mixed at a ratio of 3:2:1) through KH550; thirdly, forming a gel through in-situ compounding and ammonia water pH adjustment; and fourthly, obtaining the product through hydrothermal reaction and calcination. The innovation point lies in the combination of the gel stability mechanism and the soft template pore-forming, which solves the problems of traditional process precipitation aggregation, disordered pores and weak interface combination; the material forms a porous structure with uniform pore size, the specific surface area is significantly improved, and the snow-melting main body realizes slow release. The snow-melting rate is over 90% at -15 DEG C for 2 hours, the preparation process is simple, the cost is low, the material has the advantages of efficient snow-melting, environmental protection, low corrosion and stability, and is suitable for traffic deicing and snow-melting in severe cold regions.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of environmental protection functional materials, and particularly relates to a composite snow-melting agent material and a preparation method thereof. BACKGROUND

[0002] Ice and snow coverage in winter easily leads to traffic congestion and frequent traffic accidents. As a key material for rapid ice and snow melting, a snow-melting agent plays an irreplaceable role in traffic security. At present, the mainstream snow-melting agent is mainly chlorides (sodium chloride, calcium chloride, etc.). However, the chlorides have significant defects: the dissolution speed is fast, which leads to a local salt concentration that is too high, not only intensifying the corrosion of bridge reinforcement and vehicle chassis, but also causing soil salinization and water pollution, and harming the ecological environment; at the same time, the traditional chlorides have a low snow-melting efficiency at low temperatures, and have a limited contact area with ice and snow due to the non-porous structure, and have poor adaptability to low temperatures.

[0003] In order to improve the above problems, the industry attempts to develop porous snow-melting agents. However, the existing technology still has many deficiencies: the porous carrier-snow-melting agent composite material prepared by a physical mixing method has a weak interface between the carrier and the snow-melting agent, and the components are easily separated during use, which leads to a rapid loss of the snow-melting agent and cannot achieve a slow-release effect; the snow-melting agent particles are easily agglomerated, which blocks the pores of the carrier, reduces the specific surface area, weakens the mass transfer efficiency, and cannot fully play the contact advantage of the porous structure; some porous snow-melting agents only rely on a single pore-forming process, the pore structure is disordered, and the pore size distribution is uneven, so the slow-release performance and the low-temperature snow-melting efficiency are difficult to be improved simultaneously; more importantly, the existing composite process lacks an effective dispersion and stabilization mechanism, and the system is easily precipitated and aggregated, which leads to uneven distribution of the snow-melting components, further deteriorates the material performance, and cannot balance the environmental protection and practicality.

[0004] Therefore, it is a key to develop a composite snow-melting agent material with stable interface combination, controllable pore structure, high snow-melting efficiency, and precipitation and aggregation solved by a gel mechanism, which becomes a key to solve the current technical bottleneck. SUMMARY

[0005] The application aims to overcome the deficiencies of the prior art, and provides a soft-template-regulated composite snow-melting agent material and a preparation method thereof. The porous carrier structure is regulated by introducing a soft-template pore-forming mechanism, a gel stabilization process is innovated to solve the problem of system precipitation and aggregation, the dispersion state of the snow-melting components and the composite process are optimized, the technical pain points of agglomeration, pore blockage, weak interface combination, poor slow-release effect, and precipitation and aggregation are solved simultaneously, and the snow-melting efficiency, environmental protection, and stability are improved simultaneously.

[0006] To achieve the above purpose, the application provides the following technical scheme:

[0007] A preparation method of a composite snow-melting agent material, comprising the following steps:

[0008] S1. Porous carrier pretreatment and soft template loading: 3A zeolite is crushed and ground, hydrochloric acid solution with a mass fraction of 5%~8% is added, and stirring activation is carried out at 80 DEG C for 2~3h, and then filtration and washing are carried out until neutral, and then drying is carried out at 110 DEG C for 4h to obtain activated 3A zeolite; the activated 3A zeolite is mixed with thiourea at a mass ratio of 10:1~3, anhydrous ethanol (solid-liquid mass ratio 1:10~15) is added, ultrasonic dispersion is carried out for 20~30min, and then stirring is carried out for 30~40min to obtain a soft template loaded carrier dispersion liquid.

[0009] S2. Preparation of modified snow melting main body: the snow melting main body (sodium chloride, calcium chloride, calcium magnesium acetate mixed at a ratio of 3:2:1) is mixed with modified additive KH550 (added in an amount of 3~5% of the mass of the snow melting main body), anhydrous ethanol is added to prepare a dispersion liquid (solid-liquid mass ratio 1:15~20), ultrasonic dispersion is carried out for 30~40min to obtain a modified snow melting main body dispersion liquid.

[0010] S3. In-situ compounding and gel formation: the modified snow melting main body dispersion liquid of step 2 is mixed with the soft template loaded carrier dispersion liquid of step 1 at a mass ratio of 1:2~3, stirring is carried out at 60~70 DEG C for 1.5h, the stirring speed is adjusted to 1200~1600r / min, 10% ammonia water is added dropwise until the pH of the system is 8~9, and a gel is formed. The gel structure can lock the snow melting main body and the carrier particles through a three-dimensional network skeleton, solve the problem of precipitation and aggregation caused by the lack of a stable mechanism in traditional processes, and ensure that the snow melting components are uniformly dispersed in the pores and surface of the carrier.

[0011] S4. Hydrothermal reaction and post-treatment: the gel is transferred to a hydrothermal reaction kettle, 5 times the mass of deionized water is added, hydrothermal reaction is carried out at 150~170 DEG C for 16~24h, and then centrifugal separation, washing until neutral, drying at 80 DEG C for 6h, and then calcination at 400~500 DEG C for 3~4h are carried out. During the calcination process, the thiourea is decomposed into NH3, CO2 and other gases, and a uniformly distributed pore structure is formed, and finally a soft template regulated-gel stabilized composite snow melting agent material is obtained.

[0012] As preferred: the amount of thiourea added in step S1 is 20%~25% of the mass of the activated natural mineral;

[0013] In the present application, thiourea is used as a soft template agent, and the molecules can be uniformly loaded on the surface and inside of the activated 3A zeolite through hydrogen bonding. In the hydrothermal reaction, the thiourea molecular aggregates stably exist in the composite system of the carrier and the snow melting main body; in the calcination process, the thiourea is decomposed and volatilized, forming a uniformly distributed pore "template", and finally forming a porous structure with uniform pore size and good connectivity, greatly increasing the specific surface area and snow melting contact area of the material, and providing stable loading sites for the snow melting main body.

[0014] The present application triggers the hydrolysis and condensation of KH550 by adjusting the pH with ammonia water to form a three-dimensional network gel structure: on the one hand, the gel skeleton can physically lock the snow melting main body and the carrier particles to avoid sedimentation and separation; on the other hand, the gel system provides a stable reaction environment for in-situ compounding, and promotes the formation of chemical bonding between the carrier and the snow melting main body, thereby fundamentally solving the technical pain point of "no gel, aggregation and precipitation", and ensuring uniform and stable material performance.

[0015] In addition, the soft template regulated porous structure realizes controllable release of the snow melting main body, avoids excessive local salt concentration, and reduces the risk of corrosion and pollution.

[0016] Synergistic dispersion and stability: gel stability mechanism, KH550 modification, ultrasonic dispersion, triple action to inhibit particle aggregation, ensure that the pores are not blocked, and maintain high mass transfer efficiency.

[0017] Synergistic high efficiency and environmental protection: the composite snow melting main body considers both low-temperature snow melting efficiency and environmental protection, and the porous carrier reduces the dosage per unit area.

[0018] According to the above-mentioned mode, a composite snow melting agent material is obtained.

[0019] The present application has the following beneficial effects compared with the prior art

[0020] (1) The soft template pore-forming and gel stability synergistic mechanism is adopted, the thiourea soft template is calcined to form a porous structure with uniform pore size and good connectivity, and the gel three-dimensional network locks the snow melting components and the carrier, thereby simultaneously solving the technical problems of sedimentation and aggregation in the traditional process, disordered pores, and particle aggregation, the porosity of the material is significantly improved, and the mass transfer efficiency is optimized.

[0021] (2) Through KH550 modification and hydrothermal reaction, the Si-O-Al-N chemical bonding between the snow melting main body and the 3A zeolite carrier is realized, and the interface bonding stability is greatly enhanced in cooperation with the physical constraint of the porous structure, the snow melting agent is controllably released, the cumulative release rate of salt ions is only 37% in 6h, the local salt concentration is avoided to be too high, and the corrosion and pollution risk of the bridge reinforcement, vehicle, soil and water body is significantly reduced.

[0022] (3) The composite snow melting main body (sodium chloride: calcium chloride: calcium magnesium acetate = 3:2:1) synergistically plays the low-temperature activity, the ordered porous structure enlarges the ice and snow contact area, and the snow melting rate reaches 91.2% in 2h at-15℃, which meets the efficient deicing and snow melting demand in severe cold regions.

[0023] (4) The low-cost 3A zeolite is used as the carrier, and the thiourea is used as the soft template agent, the preparation process is simple and controllable, the parameters are easy to adjust, the large-scale production is difficult, the efficiency, environmental protection and economy are considered, and the environmental protection policy requirements are met. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1is a scanning electron microscope picture of the product prepared in Example 1;

[0025] Figure 2 is an XRD picture of the products prepared in Examples 1-3;

[0026] Figure 3 is an N2 adsorption-desorption isotherm of the products of Example 1, Comparative Example 1 and Comparative Example 2;

[0027] Figure 4 is a comparison curve of snow melting rate of the products of Example 1 and Comparative Examples 1-3;

[0028] Figure 5 is a sustained-release performance curve of the products of Example 1, Comparative Example 1 and Comparative Example 2. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below. The following content is only an example and description of the concept of the present application. Those skilled in the art can make various modifications or supplements to the described specific implementation cases or use similar ways instead, as long as they do not deviate from the concept of the present application, which shall belong to the protection scope of the present application.

[0030] The above preparation method of the present application will be described below through specific examples and comparative examples.

[0031] Example 1

[0032] A preparation method of a composite snow-melting agent, comprising the following steps:

[0033] S1. Pretreatment of porous carrier and loading of soft template: 100 g of 3A zeolite was crushed, 6% hydrochloric acid solution was added, and stirring activation was carried out at 80°C for 2.5 h. After filtration and washing to neutral, drying was carried out at 110°C for 4 h. Then 22 g of thiourea was added, 1200 g of anhydrous ethanol was added, ultrasonic dispersion was carried out for 25 min, and stirring was carried out at 50°C for 35 min to obtain a carrier dispersion liquid.

[0034] S2. Preparation of modified snow-melting main body: 60 g of sodium chloride, 40 g of calcium chloride and 20 g of calcium magnesium acetate were mixed, 4.8 g of KH550 was added, 2400 g of anhydrous ethanol was added, ultrasonic dispersion was carried out for 35 min to obtain a modified snow-melting main body dispersion liquid.

[0035] S3. In-situ compounding and gel formation: the above two dispersion liquids were mixed at a mass ratio of 1:2.5, stirring was carried out at 500 r / min at 65°C for 1.5 h; the stirring speed was adjusted to 1400 r / min, 10% ammonia water was added at a rate of 1.5 mL / min, and the system pH was adjusted to 8.5 to form a stable gel.

[0036] S4. Hydrothermal reaction and post-processing: transfer the gel to a hydrothermal reactor, add 5 times the mass of deionized water to the gel, react at 160°C for 20h; after cooling, centrifugal separation at 8000r / min, washing to neutral, drying at 80°C for 6h, calcining at 450°C for 3.5h, to obtain a composite snow-melting agent material.

[0037] Example 2

[0038] A method for preparing a composite snow-melting agent, comprising the following steps:

[0039] S1. Pretreatment of porous carrier and loading of soft template: take 100g of 3A zeolite, add a mass fraction of 5% hydrochloric acid solution, stir and activate at 80°C for 2h, filter and wash to neutral, dry at 110°C for 4h; add 20g of thiourea, add 1000g of anhydrous ethanol, ultrasonic dispersion at 500W for 20min, stir at 50°C for 30min, to obtain a carrier dispersion liquid.

[0040] S2. Preparation of modified snow-melting main body: take 60g of sodium chloride, 40g of calcium chloride, and 20g of calcium magnesium acetate mixture, add 3.6g of KH550, add 1800g of anhydrous ethanol, ultrasonic dispersion at 500W for 30min, to obtain a modified snow-melting main body dispersion liquid.

[0041] S3. In-situ compounding and gel formation: mix the above two dispersion liquids in a mass ratio of 1:2, stir at 60°C at 600r / min for 1.5h; adjust the stirring speed to 1200r / min, add 10% ammonia water at a rate of 1mL / min, until the pH of the system reaches 8, to form a stable gel.

[0042] S4. Hydrothermal reaction and post-processing: transfer the gel to a hydrothermal reactor, add 5 times the mass of deionized water to the gel, react at 160°C for 20h; after cooling, centrifugal separation at 8000r / min, washing to neutral, drying at 80°C for 6h, calcining at 450°C for 3.5h, to obtain a composite snow-melting agent material.

[0043] Example 3

[0044] A method for preparing a composite snow-melting agent, comprising the following steps:

[0045] S1. Pretreatment of porous carrier and loading of soft template: take 100g of 3A zeolite, add a mass fraction of 5% hydrochloric acid solution, stir and activate at 80°C for 2h, filter and wash to neutral, dry at 110°C for 4h; add 20g of thiourea, add 1000g of anhydrous ethanol, ultrasonic dispersion at 500W for 20min, stir at 50°C for 30min, to obtain a carrier dispersion liquid.

[0046] S2. Preparation of modified snow-melting main body: 60 g of sodium chloride, 40 g of calcium chloride, and 20 g of calcium magnesium acetate were mixed, 6 g of KH550 was added, 3000 g of anhydrous ethanol was added, and ultrasonic dispersion was performed at 400 W for 40 min to obtain a modified snow-melting main body dispersion liquid.

[0047] S3. In-situ compounding and gel formation: the two dispersion liquids above were mixed at a mass ratio of 1:3, and stirring was performed at 70°C and 800 r / min for 1.5 h; the stirring speed was adjusted to 1600 r / min, 10% ammonia water was added at a rate of 2 mL / min, and a stable gel was formed when the pH of the system was 9.

[0048] S4. Hydrothermal reaction and post-processing: the gel was transferred to a hydrothermal reaction kettle, 5 times the mass of deionized water was added, and reaction was performed at 170°C for 24 h; after cooling, centrifugal separation was performed at 10000 r / min, washing was performed until neutral, drying was performed at 80°C for 6 h, and calcination was performed at 500°C for 4 h to obtain a composite snow-melting agent material.

[0049] Comparative Example 1

[0050] In step S1, no thiourea was added, and the remaining steps were the same as in Example 1.

[0051] Comparative Example 2

[0052] S1. The porous carrier was pretreated and the soft template was loaded as in Example 1.

[0053] S2. The modified snow-melting main body was prepared as in Example 1.

[0054] S3. After mixing the two dispersion liquids, no ammonia water was added, and direct stirring and drying were performed without gel formation.

[0055] S4. Hydrothermal reaction and post-processing were the same as in Example 1 to obtain a snow-melting agent material.

[0056] Figure 1 is a scanning electron microscope photograph of the product prepared in Example 1; the microstructure of the product of Example 1 is directly presented: a porous structure with good pore size and connectivity is formed on the surface and inside of the material, and there is no obvious pore blockage phenomenon. The structure is derived from the pore-forming effect of the thiourea soft template, and the gel network locking effect ensures that the snow-melting main body and the 3A zeolite carrier are closely combined.

[0057] Figure 2XRD patterns of the products prepared in Examples 1-3; in the XRD patterns of the products of Examples 1-3, both the characteristic diffraction peaks of the 3A zeolite (2θ = 20.8°, 26.6°) and the characteristic peaks of sodium chloride (2θ = 28.3°) and calcium chloride (2θ = 32.5°) can be seen, and no impurity peaks are present. It is proved that through modification by KH550 and hydrothermal reaction, the snow melting main body and the carrier are chemically bonded (Si-O-Al-N bond), and no component phase change or impurity is generated, and the crystal structure of the material is stable.

[0058] Figure 3 N2 adsorption-desorption isotherms of the products of Example 1, Comparative Example 1 and Comparative Example 2; the isotherm of the product of Example 1 is a type IV isotherm, and the hysteresis loop is H1 type, indicating that it is a typical mesoporous structure; the specific surface area is significantly higher than that of Comparative Example 1 and Comparative Example 2. By comparing Comparative Example 1 (without thiourea) and Comparative Example 2 (without gel), it is proved that the soft template pore-making and the stable cooperation of the gel significantly improve the porosity and the order of the pore structure of the material, and avoid pore collapse or blockage.

[0059] Figure 4 The snow melting rate comparison curves of the products of Example 1 and Comparative Examples 1-3; under the condition of low temperature of -15℃, the snow melting rate of the product of Example 1 is 91.2% in 2h, the snow melting rate of Comparative Example 1 (without soft template) is only 57.7% in 2h, and the snow melting rate of Comparative Example 2 (without gel) is 48.5% in 2h. It is explained that the ordered porous structure expands the contact area of ice and snow, and the composite snow melting main body (sodium chloride + calcium chloride + calcium magnesium acetate) cooperates to improve the low temperature activity, and the gel stabilizes to ensure uniform release of the snow melting components.

[0060] Figure 5 The slow-release performance curves of the products of Example 1, Comparative Example 1 and Comparative Example 2. The salt ion release rate of the product of Example 1 remains stable (cumulative release rate 37%) within 6h, the cumulative release rate of Comparative Example 1 (without soft template) reaches 59% in 6h, and the cumulative release rate of Comparative Example 2 (without gel) reaches 70% in 6h. It is proved that the physical constraint of the soft template porous structure and the chemical locking of the gel network realize the controllable slow release of the snow melting main body, avoid the local salt concentration being too high, and reduce the risk of corrosion and pollution.

Claims

1. A method for preparing a composite de-icing agent material, characterized in that, Includes the following steps: S1. Pretreatment of porous carrier and loading of soft template: 3A zeolite was crushed and ground, hydrochloric acid solution was added, stirred and activated at 80°C, filtered and washed until neutral, and dried at 110°C for 4h to obtain activated 3A zeolite; Activated 3A zeolite was mixed with thiourea, anhydrous ethanol was added, and the mixture was ultrasonically dispersed and stirred to obtain a carrier dispersion loaded with a soft template. S2. Preparation of modified snow melting substrate: The snow melting substrate is mixed with the modifying agent KH550, and anhydrous ethanol is added to prepare a dispersion. The dispersion is ultrasonically dispersed to obtain a modified snow melting substrate dispersion. The snow melting substrate is composed of sodium chloride, calcium chloride, and calcium magnesium acetate. S3. In-situ composite and gel formation: The modified snow melting host dispersion from step S2 is mixed with the carrier dispersion loaded with the soft template from step S1. The mixture is stirred at 60~70℃ for 1.5h. After adjusting the stirring speed, ammonia is added dropwise until the system forms a gel. S4. Hydrothermal reaction and post-treatment: The gel was transferred to a hydrothermal reactor, and five times the mass of deionized water was added to carry out the hydrothermal reaction. After cooling, the gel was centrifuged, washed until neutral, dried, and then calcined to obtain the composite de-icing agent material. In step S1, the mass ratio of activated 3A zeolite to thiourea is 10:1~3, and the solid-liquid mass ratio of anhydrous ethanol to solid material is 1:10~15. In step S2, the mass ratio of sodium chloride, calcium chloride, and calcium magnesium acetate in the snow melting substrate is 3:2:1, and the amount of KH550 added is 3-5% of the mass of the snow melting substrate. In step S2, the solid-liquid mass ratio of the dispersion is 1:15~20; In step S3, the mass ratio of the modified snow melting main dispersion to the carrier dispersion loaded with the soft template is 1:2~3, the mass fraction of the ammonia water is 10%, and the pH of the system is adjusted to 8~9.

2. The preparation method according to claim 1, characterized in that, In step S1, the hydrochloric acid solution has a mass fraction of 5% to 8%, and the stirring activation time is 2 to 3 hours.

3. The preparation method according to claim 1, characterized in that, In step S1, the ultrasonic dispersion time is 20-30 min and the stirring time is 30-40 min.

4. The preparation method according to claim 1, characterized in that, In step S2, the ultrasonic dispersion time is 30~40 min.

5. The preparation method according to claim 1, characterized in that, In step S3, the rotation speed after adjusting the stirring speed is 1200~1600 r / min.

6. The preparation method according to claim 1, characterized in that, In step S4, the hydrothermal reaction temperature is 150~170℃, the reaction time is 16~24h, the drying temperature is 80℃, the drying time is 6h, and the calcination temperature is 400~500℃, the calcination time is 3~4h.

7. A composite de-icing agent material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 6.

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