Gradient porous glass material based on coal-based solid waste as well as preparation method and application of gradient porous glass material

Abstract

The invention discloses a gradient porous glass material based on coal-based solid waste and a preparation method and application thereof.The preparation method of the gradient porous glass material based on the coal-based solid waste comprises the steps that an initial glass flat plate and a functional oxide flat plate are attached and pressed, heat treatment is conducted for 1-100 hours at the temperature of 600-900 DEG C, and the gradient porous glass material based on the coal-based solid waste is obtained; separating the initial glass plate from the functional oxide plate, and obtaining a gradient doped split-phase glass plate based on the initial glass plate; carrying out surface corrosion treatment on the gradient doped split-phase glass plate, then carrying out acid dissolution treatment, washing to be neutral, and drying to obtain the gradient porous glass material based on the coal-based solid waste. The technical bottleneck of the traditional homogeneous porous material is effectively solved, and the gradient porous glass material based on the coal-based solid waste shows higher flux than the homogeneous porous glass material under the same interception aperture and operation conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of glass materials, and specifically relates to a gradient porous glass material based on coal-based solid waste, and a preparation method and application thereof. Background Art

[0002] Porous glass materials, due to their unique pore structure and excellent physical and chemical properties, have shown significant application value in membrane separation. However, traditional porous glass preparation processes often rely on high-purity raw materials, resulting in high production costs and a significant gap in current green and low-carbon development concepts.

[0003] In recent years, the technical route of preparing porous glass materials using coal-based solid waste as raw materials has provided a new approach to solving the above problems. However, existing porous glass materials are generally uniform porous glass materials. Traditional uniform porous glass materials show obvious performance limitations in applications. In the field of membrane separation, since the pore size of uniform porous glass materials is uniformly distributed, when the fluid contains particles of different sizes, all particles will be concentrated on the membrane surface, which is easy to clog; in addition, uniform porous glass materials are limited by their pore size distribution. When used as a filter membrane, it is difficult to take into account both the interception effect and the permeation flux. In the field of membrane emulsification, although uniform pore size can control the initial size of droplets to a certain extent, when faced with dispersed phases or continuous phase systems of different viscosities, a single pore size distribution makes it difficult to flexibly adjust the droplet formation efficiency and stability. In addition, during the long-term emulsification process, the pore size uniformity is also prone to cause local droplet aggregation and membrane pore clogging.

[0004] Therefore, there is an urgent need to innovate from the material structure design level and develop porous glass materials with new pore structures, so as to achieve high-value utilization of coal-based solid waste while breaking through the technical limitations of traditional separation membrane materials in mass transfer efficiency, separation performance, and dispersion performance. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the purpose of the present invention is to provide a method for preparing a gradient porous glass material based on coal-based solid waste. The present invention establishes a synergistic mechanism of diffusion-phase separation, takes coal-based solid waste such as coal gangue and fly ash as basic raw materials, constructs a borosilicate glass system, and utilizes the thermodynamic diffusion gradient of functional oxides to induce phase separation, thereby successfully preparing a porous glass material with a gradient porous structure.

[0006] Another object of the present invention is to provide a gradient porous glass material based on coal-based solid waste obtained by the above preparation method.

[0007] Another object of the present invention is to provide the application of the above-mentioned gradient porous glass material based on coal-based solid waste as a filtration membrane / emulsification membrane.

[0008] The purpose of the present invention is achieved through the following technical solutions.

[0009] A method for preparing a gradient porous glass material based on coal-based solid waste comprises the following steps: S1, laminating and pressing an initial glass plate and a functional oxide plate, and heat treating them at 600-900° C. for 1-100 hours (so that the functional oxide in the functional oxide plate diffuses into the initial glass plate in a gradient manner and the initial glass plate undergoes phase separation), separating the initial glass plate and the functional oxide plate to obtain a gradient-doped phase-separated glass plate based on the initial glass plate; The method for obtaining an initial glass flat plate comprises: mixing coal-based solid waste, quartz sand, boron oxide and an additive until uniform, melting the mixture at 1000-1700° C. for 1-5 hours to obtain molten glass, casting the molten glass into a shape, and annealing the mixture at 500-600° C. for 0.5-2 hours to obtain an initial glass flat plate, wherein the ratio of the coal-based solid waste, quartz sand, boron oxide and the additive is (1-7): (1-3): (2-5): (1-7) by mass, and the additive is one or more of sodium carbonate, silicon oxide, calcium oxide, zirconium oxide, lithium oxide, magnesium oxide and ferric oxide; Coal-based solid waste includes one or more of fly ash, coal gangue and bottom ash; The functional oxide plate comprises: a functional oxide, wherein the functional oxide is at least one of silicon oxide, calcium oxide, zirconium oxide, lithium oxide, magnesium oxide and ferric oxide; In S1, the method for obtaining the functional oxide flat plate includes: pressing the functional oxide (powder) into a shape, and polishing it until the surface is smooth to obtain the functional oxide flat plate.

[0010] In S1, the initial glass plate and the functional oxide plate have the same shape and size.

[0011] In S1, the initial glass plate and the functional oxide plate are attached and pressed together, and the pressure of the force acting on the contact surface of the initial glass plate and the functional oxide plate during pressing is 0.01-0.1 MPa.

[0012] In S1, the heat treatment time at 600 to 900° C. is preferably 10 to 48 hours.

[0013] S2, first subjecting the gradient-doped phase-separated glass plate to surface corrosion treatment, then subjecting it to acid dissolution treatment, washing it to neutrality, and drying it to obtain a gradient porous glass material based on coal-based solid waste, wherein the surface corrosion treatment includes: soaking it in a corrosion solution, and the corrosion solution is an alkaline solution.

[0014] In S2, the surface corrosion treatment includes: immersing in an alkaline solution at 25~150℃ for 0.5~5h.

[0015] In the above technical solution, the alkaline solution is a sodium hydroxide aqueous solution, and the concentration of sodium hydroxide in the sodium hydroxide aqueous solution is 1~6 mol / L.

[0016] In S2, the acid dissolution treatment includes: soaking in an acidic solution at 25-80°C for 2-80 hours.

[0017] In the above technical solution, the acidic solution is a mixture of acid molecules and water, the acid molecules are at least one of HCl, HNO3, H2SO4, H3PO4 and H3BO3, and the concentration of the acid molecules in the acidic solution is 1~6 mol / L.

[0018] In S2, washing is performed with water.

[0019] The above preparation method obtains the gradient porous glass material based on coal-based solid waste.

[0020] In the above technical solution, the pore size of the gradient porous glass material based on coal-based solid waste gradually increases or decreases along the thickness direction.

[0021] In the above technical solution, the porosity of the gradient porous glass material based on coal-based solid waste is 30-80%.

[0022] The above-mentioned gradient porous glass material based on coal-based solid waste is used as a filter membrane / emulsification membrane.

[0023] In the above technical solution, the thickness of the gradient porous glass material based on coal-based solid waste is 0.3~25.0 mm.

[0024] In the above technical solution, the side with larger pore size of the gradient porous glass material based on coal-based solid waste is used as the front side, and the side with smaller pore size is used as the back side. When the gradient porous glass material is used as a filter membrane / emulsification membrane, the front side is facing upstream of the fluid.

[0025] Compared with the prior art, the present invention has the following beneficial effects: 1. The gradient porous glass material based on coal-based solid waste of the present invention has a gradient porous structure. When used as a filter membrane, the side with a larger pore size of the gradient porous glass material based on coal-based solid waste serves as the front side, and the side with a smaller pore size serves as the back side. With the front side facing the upstream of the fluid, the larger particles in the fluid can be first intercepted. As the fluid flows in the filter membrane, the pore size gradually shrinks, and the filter membrane then intercepts smaller particles or molecules. This "large first, small later" interception mode avoids the problem of all pollutants being concentrated on the membrane surface, and reduces "instantaneous pollution" caused by large particles blocking small pores; pollutants are distributed along the pore size gradient inside the membrane, rather than accumulating on a single surface, making the flow resistance of the fluid in the membrane more uniform, and the concentration polarization (pollutants are enriched on the membrane surface to form a high concentration layer) phenomenon is weakened, thereby reducing the membrane performance degradation caused by long-term polarization; 2. When the gradient porous glass material based on coal-based solid waste of the present invention is used as a filter membrane, the side with a larger pore size is used as the front side, which provides a smoother initial channel for the fluid, reduces the resistance of the fluid to enter the interior of the membrane, and as the fluid flows in the direction of decreasing pore size, it can also intercept smaller pollutants. While ensuring the interception accuracy, it avoids the problem of small pores in the uniform pore size membrane hindering the fluid, thereby improving the flux. The present invention achieves a balance between interception accuracy and flux, and is particularly suitable for filtering fluids containing complex multi-component pollutants. If the traditional uniform pore size membrane pursues high interception accuracy, the pore size of the filter membrane needs to be smaller, which often requires sacrificing flux. If high flux is pursued, the pore size of the filter membrane needs to be larger, and pollutants with smaller sizes cannot be intercepted, resulting in a decrease in the interception effect. The present invention effectively solves the technical bottleneck of traditional uniform porous materials. Under the same interception pore size and operating conditions, the gradient porous glass material based on coal-based solid waste shows an improvement in flux compared to the homogeneous porous glass material.

[0026] 3. When the gradient porous glass material based on coal-based solid waste of the present invention is used as a filter membrane, the pollutants are gradiently distributed in the membrane, making the force on the membrane more uniform, avoiding the problem of membrane pore tearing caused by large particles impacting small pores on the surface, and reducing damage.

[0027] 4. When the gradient porous glass material based on coal-based solid waste of the present invention is used as a filter membrane, the large-aperture channels are more easily penetrated by the cleaning liquid, and the pollutants inside the membrane are also easier to remove due to their dispersed distribution, the regeneration efficiency is higher, and good performance can be maintained after multiple cleanings.

[0028] 5. When the fluid to be filtered contains pollutants of various sizes from large to small (such as sewage containing sediment, colloids, and small molecular organic matter), the gradient porous structure can specifically intercept different components, completing one-step separation without the need for multi-stage filtration equipment, simplifying the process and reducing costs.

[0029] In summary, the technical solution of the present invention realizes the synergistic innovation of high-value utilization of coal-based solid waste and pore structure design, and provides a new porous glass material with excellent performance in the field of membrane separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a SEM image of the bottom section of the uniform porous glass material based on coal-based solid waste prepared in Example 1 at a magnification of 500;

[0031] Figure 2 This is a SEM image of the bottom section of the uniform porous glass material based on coal-based solid waste prepared in Example 1 at a magnification of 5000;

[0032] Figure 3 This is a SEM image of the middle section of the uniform porous glass material based on coal-based solid waste prepared in Example 1 at a magnification of 500;

[0033] Figure 4 This is a SEM image of the middle section of the uniform porous glass material based on coal-based solid waste prepared in Example 1 at a magnification of 5000;

[0034] Figure 5 This is a SEM image of the top section of the uniform porous glass material based on coal-based solid waste prepared in Example 1 at a magnification of 500;

[0035] Figure 6 This is a SEM image of the top section of the uniform porous glass material based on coal-based solid waste prepared in Example 1 at a magnification of 5000;

[0036] Figure 7 This is a SEM image of the bottom section of the gradient porous glass material based on coal-based solid waste prepared in Example 2 at a magnification of 500;

[0037] Figure 8 This is a SEM image of the bottom section of the gradient porous glass material based on coal-based solid waste prepared in Example 2 at a magnification of 5000;

[0038] Figure 9 This is a SEM image of the middle section of the gradient porous glass material based on coal-based solid waste prepared in Example 2 at a magnification of 500;

[0039] Figure 10 This is a SEM image of the middle section of the gradient porous glass material based on coal-based solid waste prepared in Example 2 at a magnification of 5000;

[0040] Figure 11 This is a SEM image of the top section of the gradient porous glass material based on coal-based solid waste prepared in Example 2 at a magnification of 500;

[0041] Figure 12 This is a SEM image of the top section of the gradient porous glass material based on coal-based solid waste prepared in Example 2 at a magnification of 5000;

[0042] Figure 13 This is an XCT image of the gradient porous glass material based on coal-based solid waste prepared in Example 2;

[0043] Figure 14 This is a SEM image of the bottom section of the gradient porous glass material based on coal-based solid waste prepared in Example 3 at a magnification of 500;

[0044] Figure 15 This is a SEM image of the bottom section of the gradient porous glass material based on coal-based solid waste prepared in Example 3 at a magnification of 5000;

[0045] Figure 16 This is a SEM image of the middle section of the gradient porous glass material based on coal-based solid waste prepared in Example 3 at a magnification of 500;

[0046] Figure 17 This is a SEM image of the middle section of the gradient porous glass material based on coal-based solid waste prepared in Example 3 at a magnification of 5000;

[0047] Figure 18 This is a SEM image of the top section of the gradient porous glass material based on coal-based solid waste prepared in Example 3 at a magnification of 500;

[0048] Figure 19 This is a SEM image of the top section of the gradient porous glass material based on coal-based solid waste prepared in Example 3 at a magnification of 5000;

[0049] Figure 20 The contact angle of the gradient porous glass material based on coal-based solid waste prepared in Example 2 before modification with water;

[0050] Figure 21 The contact angle of the modified coal-based solid waste-based gradient porous glass material prepared in Example 2 with water;

[0051] Figure 22 The pore size distribution of the uniform porous glass material based on coal-based solid waste prepared in Example 1, and the gradient porous glass materials based on coal-based solid waste prepared in Example 2 and Example 3;

[0052] Figure 23 The chemical compositions of the uniform porous glass material based on coal-based solid waste prepared in Example 1, and the gradient porous glass materials based on coal-based solid waste prepared in Examples 2 and 3;

[0053] Figure 24The glass transition temperatures are the uniform porous glass material based on coal-based solid waste prepared in Example 1 and the gradient porous glass materials based on coal-based solid waste prepared in Example 2 and Example 3. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described below with reference to specific embodiments.

[0055] The raw material information involved in the following examples is as follows:

[0056] The fly ash purchased from Inner Mongolia Shangdu Power Generation Co., Ltd. contains (by mass percentage) the following: SiO₂: 40.17%, Al₂O₃: 17.5%, SO₃: 10.78%, Fe₂O₃: 10.86%, CaO: 9.05%, MgO: 5.74%, K₂O: 2.30%, Na₂O: 1.44%, and other components (organic and reducing substances, etc.): 2.16%. Because this fly ash contains small amounts of organic and reducing substances, these substances, if not removed first, can have two negative effects: first, their decomposition or oxidation during the subsequent high-temperature melting process can lead to additional bubbles and melt splashing; second, their chemical reactions can cause significant corrosion damage to the precious metal platinum-rhodium alloy crucible. Therefore, the purchased fly ash is calcined at 900°C for 10 hours to remove these organic and reducing substances before use.

[0057] Example 1

[0058] A method for preparing a uniform porous glass material (homogeneous porous glass material) based on coal-based solid waste comprises the following steps: S1, mixing coal-based solid waste (fly ash), quartz sand, boron oxide and additives until uniform, placing the mixture in a crucible made of platinum-rhodium alloy, melting the mixture in a high-temperature furnace at 1400°C for 2 hours to obtain molten glass, casting the molten glass into a shape, annealing the mixture at 500°C for 0.3 hours, cutting and polishing the mixture to obtain an initial glass plate with a size of 20 mm × 10 mm × 2 mm, and heat-treating the initial glass plate in a low-temperature furnace at 700°C for 24 hours to perform phase separation to obtain a phase-separated glass plate (silicon-rich phase and acid-soluble phase), wherein the ratio of the coal-based solid waste (fly ash), quartz sand, boron oxide and additives is 5:2:3:3 by mass, and the additive is a mixture of calcium oxide and sodium carbonate, and the ratio of calcium oxide to sodium carbonate is 2:1 by mass; S2, the phase-separated glass plate is first subjected to surface corrosion treatment to remove the dense silicon oxide layer on the surface (immersed in a sodium hydroxide aqueous solution at 30°C for 0.5 h for surface corrosion treatment, and the concentration of NaOH in the sodium hydroxide aqueous solution is 1 mol / L), and then subjected to acid dissolution treatment to remove the acid-soluble phase in the phase-separated glass plate (immersed in an acidic solution at 30°C for 24 h for acid dissolution treatment, the acidic solution is hydrochloric acid, and the concentration of HCl in the hydrochloric acid is 1 mol / L), washed with water to neutrality (pH = 7), and dried at 60°C for 30 min to obtain a uniform porous glass material based on coal-based solid waste with a thickness of 2.0 mm.

[0059] The cross-sectional micromorphology of the uniform porous glass material based on coal-based solid waste prepared in Example 1 was observed using a scanning electron microscope. Figures 1 to 6 As shown, Figure 1 This is a SEM image of the bottom of a cross section of a uniform porous glass material based on coal-based solid waste at 500x magnification. Figure 2 for Figure 1 A local enlarged view (SEM of the bottom position of the cross section of the uniform porous glass material based on coal-based solid waste at 5000 times magnification), Figure 3 This is a SEM image of the middle section of a uniform porous glass material based on coal-based solid waste at 500x magnification. Figure 4 for Figure 3 A local enlarged view (SEM of the middle position of the cross section of the uniform porous glass material based on coal-based solid waste at 5000 times magnification), Figure 5 This is a SEM image of the top of a cross section of a uniform porous glass material based on coal-based solid waste at 500x magnification. Figure 6 for Figure 5 A local enlarged view (SEM of the top position of the cross section of the uniform porous glass material based on coal-based solid waste at 5000 times). Figures 1 to 6 It can be seen that the pore structures of different end faces of the uniform porous glass material based on coal-based solid waste prepared in Example 1 are highly consistent.

[0060] Example 2

[0061] A method for preparing a gradient porous glass material based on coal-based solid waste comprises the following steps: S1, the initial glass plate and the functional oxide plate are attached and pressed at room temperature (the initial glass plate and the functional oxide plate are placed horizontally and the functional oxide plate is located above the initial glass plate, and the pressure (including the weight of the functional oxide plate above) is adjusted by weights so that the pressure at the contact surface of the initial glass plate and the functional oxide plate during pressing is 0.03 MPa), and placed in a low-temperature furnace at 700 ° C for 24 hours to allow the functional oxide in the functional oxide plate to diffuse gradiently into the initial glass plate. At the same time, the initial glass plate undergoes phase separation, and the initial glass plate and the functional oxide plate are manually separated to obtain a gradient-doped phase-separated glass plate based on the initial glass plate, wherein the method for obtaining the initial glass plate comprises: mixing coal-based solid waste (fly ash), quartz sand, boron oxide and additives until uniform, placing in a crucible made of platinum-rhodium alloy, melting in a high-temperature furnace at 1400 ° C for 2 hours to obtain molten glass, casting the molten glass into shape, and annealing at 500 ° C for 0.3 hours, cutting and polishing to obtain a size of 20 mm × 10 mm × 2 The initial glass plate of mm, the ratio of coal-based solid waste (fly ash), quartz sand, boron oxide and additive is 5:2:3:3 by mass, and the additive is a mixture of calcium oxide and sodium carbonate, and the ratio of calcium oxide to sodium carbonate is 2:1 by mass; The method for obtaining a functional oxide flat plate comprises: placing a functional oxide (powder) in a mold of a Miqi manual tablet press (purchased from Miqi Instrument Equipment Co., Ltd., Changsha, Hunan) at room temperature, setting tableting parameters as follows: a pressure of 30 MPa and a holding time of 50 seconds, pressing the flat plate into a shape, and polishing the plate until the surface is flat and smooth to obtain a functional oxide flat plate having a size of 20 mm × 10 mm × 2 mm, wherein the functional oxide is aluminum oxide; S2, the gradient-doped phase-separated glass plate was first subjected to surface corrosion treatment to remove the dense silicon oxide layer on the surface (immersed in a sodium hydroxide aqueous solution at 30°C for 0.5 h for surface corrosion treatment, and the concentration of NaOH in the sodium hydroxide aqueous solution was 1 mol / L), and then immersed in an acidic solution at 30°C for 24 h for acid dissolution treatment, the acidic solution was hydrochloric acid (the concentration of HCl in hydrochloric acid was 1 mol / L), washed with water to neutrality (pH = 7), and dried at 60°C for 30 min to obtain a gradient porous glass material based on coal-based solid waste with a size of 20 mm × 10 mm × 2 mm.

[0062] The cross-sectional micromorphology of the coal-based solid waste-based gradient porous glass material prepared in Example 2 was observed using a scanning electron microscope. Figures 7 to 12 As shown, Figure 7 This is a SEM image of the bottom of the cross section of the gradient porous glass material based on coal-based solid waste at 500 times magnification (i.e., the end close to the contact surface between the initial glass plate and the functional oxide plate). Figure 8 for Figure 7 A local enlarged view (SEM of the bottom section of the gradient porous glass material based on coal-based solid waste at 5000 times magnification), Figure 9 This is a SEM image of the middle section of the gradient porous glass material based on coal-based solid waste at 500 times magnification. Figure 10 for Figure 9 A local enlarged view (SEM of the middle section of the gradient porous glass material based on coal-based solid waste at 5000 times magnification), Figure 11 This is a SEM image of the top section of the gradient porous glass material based on coal-based solid waste at 500 times magnification. Figure 12 for Figure 11 A local enlarged view (SEM of the top section of the gradient porous glass material based on coal-based solid waste at 5000 times magnification). Figures 7 to 12 It can be seen that the pore structure is curved cylindrical and intertwined, extending from the contact surface of the initial glass plate and the functional oxide plate to the distal end. The pore size of the gradient porous glass material based on coal-based solid waste shows a trend of gradually increasing. This is because Example 2 uses alumina as the functional oxide, which inhibits phase separation.

[0063] The three-dimensional structure of the gradient porous glass material based on coal-based solid waste prepared in Example 2 was determined by X-ray tomography (XCT). The test results are as follows: Figure 13 As shown in the XCT image, the pore size varies gradually along the x-axis (i.e., the thickness direction of the graded porous glass material based on coal-based solid waste). The pore size is particularly noticeably smaller near the interface with the functional oxide plate than at the end further away from the plate. The pore size of the graded porous glass material based on coal-based solid waste is uniformly distributed on any surface perpendicular to the thickness direction.

[0064] Example 3 A method for preparing a gradient porous glass material based on coal-based solid waste is basically the same as that of Example 2, with the only difference being that the functional oxide is calcium oxide.

[0065] The cross-sectional micromorphology of the coal-based solid waste-based gradient porous glass material prepared in Example 3 was observed using a scanning electron microscope. Figures 14 to 19 As shown, Figure 14 This is a SEM image of the bottom of the cross section of the gradient porous glass material based on coal-based solid waste at 500 times magnification (i.e., the end close to the contact surface between the initial glass plate and the functional oxide plate). Figure 15 for Figure 14 A local enlarged view (SEM of the bottom section of the gradient porous glass material based on coal-based solid waste at 5000 times magnification), Figure 16 This is a SEM image of the middle section of the gradient porous glass material based on coal-based solid waste at 500 times magnification. Figure 17 for Figure 16A local enlarged view (SEM of the middle section of the gradient porous glass material based on coal-based solid waste at 5000 times magnification), Figure 18 This is a SEM image of the top section of the gradient porous glass material based on coal-based solid waste at 500 times magnification. Figure 19 for Figure 18 A local enlarged view (SEM of the top section of the gradient porous glass material based on coal-based solid waste at 5000 times magnification). Figures 14 to 19 It can be seen that the pore structure is curved cylindrical and intertwined, extending from the contact surface of the initial glass plate and the functional oxide plate to the distal end. The pore size of the gradient porous glass material based on coal-based solid waste shows a trend of gradually decreasing. This is because Example 3 uses calcium oxide as the functional oxide, which promotes phase separation.

[0066] The coal-based solid waste-based gradient porous glass material prepared in Example 2 was calcined in a muffle furnace at 500°C for 2 hours, cooled to room temperature, and ultrasonically treated in deionized water for 0.5 hours (ultrasonic frequency of 40 kHz, ultrasonic power of 100 W). It was then immersed in an aqueous solution of a silane coupling agent for modification: ultrasonic treatment was performed for 2 hours under a vacuum of 0.08 MPa (ultrasonic frequency of 40 kHz, ultrasonic power of 100 W). Finally, it was placed in a thermostat at 120°C for a coupling reaction for 4 hours. The concentration of the silane coupling agent in the aqueous solution was 3% (v / v), and the silane coupling agent was γ-chloropropyltrimethoxysilane (KP-18C). The contact angles of the coal-based solid waste-based gradient porous glass material with water before and after modification were measured using a contact angle meter. The contact angles of the coal-based solid waste-based gradient porous glass material with water before modification are shown in Figure 2. Figure 20 As shown in the figure, the contact angle between the modified coal-based solid waste-based gradient porous glass material and water is as follows: Figure 21 shown.

[0067] Depend on Figure 20 and Figure 21 It can be seen that the gradient porous glass material based on coal-based solid waste before modification is extremely hydrophilic ( CA =0 o ), a hydrophobic surface can be obtained after modification with a silane coupling agent ( CA =138 o The surface of the graded porous glass material based on coal-based solid waste is rich in Si-OH groups, making it hydrophilic. When modified by connecting hydrophobic molecular chains through silyl ether bonds, it becomes hydrophobic. The surface of the graded porous glass material based on coal-based solid waste has controllable wettability, which significantly expands the application range of the material.

[0068] The pore size distribution of the material is measured by mercury intrusion instrument, and the test results are as follows Figure 22As shown, the material is one of the uniform porous glass material based on coal-based solid waste prepared in Example 1, and the gradient porous glass material based on coal-based solid waste prepared in Example 2 and Example 3.

[0069] Depend on Figure 22 It can be seen that the average pore size of the uniform porous glass material based on coal-based solid waste prepared in Example 1 is 3.31 μm and the porosity is 54.22%; the average pore size of the gradient porous glass material based on coal-based solid waste prepared in Example 2 is 2.74 μm and the porosity is 68.77%; the average pore size of the gradient porous glass material based on coal-based solid waste prepared in Example 3 is 3.98 μm and the porosity is 45.17%. Figure 22 The pore size distribution further confirms that the uniform porous glass material based on coal-based solid waste prepared in Example 1 has a uniform pore size distribution on an overall scale; the overall pore size distribution of the graded porous glass material based on coal-based solid waste prepared in Example 2 is shifted toward smaller pore sizes compared to the uniform porous glass material based on coal-based solid waste. The overall pore size distribution of the graded porous glass material based on coal-based solid waste prepared in Example 3 is shifted toward larger pore sizes compared to the uniform porous glass material based on coal-based solid waste.

[0070] The pore structure in the SEM image was measured using Image J software, and the retention pore sizes of the uniform porous glass material based on coal-based solid waste prepared in Example 1 and the gradient porous glass materials based on coal-based solid waste prepared in Example 2 and Example 3 were respectively obtained. Among them, the retention pore size of the uniform porous glass material based on coal-based solid waste prepared in Example 1 was 3.30 μm; the retention pore size at the bottom of the cross section of the gradient porous glass material based on coal-based solid waste prepared in Example 2 was 0.95 μm; and the retention pore size at the top of the cross section of the gradient porous glass material based on coal-based solid waste prepared in Example 3 was 3.30 μm.

[0071] The material was crushed and dispersed evenly, and then the chemical composition of the material was determined using X-ray fluorescence spectrometer (XRF). The test results were as follows: Figure 23 As shown, the material is one of the phase-separated glass flat plate prepared by S1 of Example 1 and the gradient-doped phase-separated glass flat plate prepared by S1 of Examples 2-3. Figure 23It can be seen that the Al2O3 content in the phase-separated glass plate prepared in Example 1 was 6.4 wt%, and the Al2O3 content in the gradient-doped phase-separated glass plate prepared in Example 2 was 7.3 wt%, further demonstrating that Al2O3 permeated into the initial glass plate in Example 2. The CaO content in the phase-separated glass plate prepared in Example 1 was 23.7 wt%, and the CaO content in the gradient-doped phase-separated glass plate prepared in Example 3 was 24.6 wt%, further demonstrating that CaO permeated into the initial glass plate in Example 3. Specifically, by controlling the diffusion behavior of the functional oxide after contact with the initial glass plate (base glass), and by utilizing the differences in composition at the contact interface and the asynchronicity of phase separation behavior, the microstructure of the graded porous glass material can be finely controlled.

[0072] The glass transition temperature of the material was determined by differential scanning calorimetry. Figure 24 As shown, the material is one of the uniform porous glass material based on coal-based solid waste prepared in Example 1, and the gradient porous glass material based on coal-based solid waste prepared in Example 2 and Example 3. Figure 24 As can be seen, the glass transition temperature of the uniform porous glass material based on coal-based solid waste prepared in Example 1 is 640°C; the glass transition temperature of the gradient porous glass materials based on coal-based solid waste prepared in Examples 2 and 3 is also 640°C. The gradient porous glass materials based on coal-based solid waste of the present invention have excellent temperature resistance.

[0073] The uniform porous glass material based on coal-based solid waste prepared in Example 1 and the gradient porous glass material based on coal-based solid waste prepared in Example 3 were cut into disc membranes with a diameter of 10.0 mm and used as filter membranes respectively. A cross-flow filtration system (manufacturer: Baoding Rongbai Constant Flow Pump Manufacturing Co., Ltd., model: LSP02-2DY) was used for flux testing. During the test, the side with a larger pore size of the gradient porous glass material based on coal-based solid waste prepared in Example 3 was used as the front side, and the side with a smaller pore size was used as the back side, with the front side facing the upstream of the fluid; the fluid was deionized water, and the temperature of the test environment was controlled within the range of 25.0±0.5°C. The experiment was carried out under gravity conditions and atmospheric pressure with reference to the instructions of the cross-flow filtration system, and the time required for 5 mL of deionized water to pass through the filter membrane was recorded. Each group of experiments was repeated 3 times, and the average value of the 3 experiments was taken as the permeation time for calculation. The values ​​of permeation time and flux are shown in Table 1. Among them, flux ( L The calculation formula for m² / (m²·h) is: Flux = V / ( A × t )×3600 , in, V =0.005L,A =0.0000785m 2 , t is the penetration time (s).

[0074] Table 1

[0075] As can be seen from Table 1, under the conditions of the same retention pore size (the retention pore size of the smaller side of the gradient porous glass material based on coal-based solid waste is the same as the retention pore size of the uniform porous glass material), the flux of the gradient porous glass material based on coal-based solid waste prepared in Example 3 is increased to 1.5 times that of the uniform porous glass material in Example 1, confirming the significant effect of the gradient pore size structure in improving the mass transfer performance of the membrane material.

[0076] The present invention exemplarily presents the application effect of the gradient porous glass material based on coal-based solid waste as a filter membrane. According to the similarity of the application principle, it can be known that the gradient porous glass material based on coal-based solid waste can also achieve good technical effects when used as an emulsification membrane. The pore size of the gradient porous glass material based on coal-based solid waste is a gradient decreasing structure from the feed side to the discharge side. According to the Hagen-Poiseuille law, this asymmetric structure can greatly reduce the flow resistance of the dispersed phase fluid in the emulsification membrane pores, thereby achieving a significant increase in the dispersed phase flux under the same operating pressure. At the same time, the tapered pore structure is conducive to focusing and pre-accelerating the dispersed phase fluid, reducing the flow dead zone and incomplete wetting of the internal pores, and effectively improving the proportion and utilization efficiency of the activated pores on the emulsification membrane surface. In addition, the larger pore size at the inlet reduces the risk of membrane pore clogging and enhances the stability and anti-pollution ability of the emulsification process. This structural design fundamentally solves the hydraulic bottleneck problem in the high-throughput application of homogeneous membranes while ensuring the monodispersity of the emulsion.

[0077] The above is an exemplary description of the present invention. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by other skilled in the art without expending creative labor falls within the scope of protection of the present invention.

Claims

1. A method for preparing a gradient porous glass material based on coal-based solid waste, characterized in that: The following steps are involved: S1, laminating and pressing an initial glass plate and a functional oxide plate, heat treating them at 600-900° C. for 1-100 hours, separating the initial glass plate and the functional oxide plate, and obtaining a gradient-doped phase-separated glass plate based on the initial glass plate; The method for obtaining an initial glass flat plate comprises: mixing coal-based solid waste, quartz sand, boron oxide and an additive until uniform, melting the mixture at 1000-1700° C. for 1-5 hours to obtain molten glass, casting the molten glass into a shape, and annealing the mixture at 500-600° C. for 0.5-2 hours to obtain an initial glass flat plate, wherein the ratio of the coal-based solid waste, quartz sand, boron oxide and the additive is (1-7): (1-3): (2-5): (1-7) by mass, and the additive is one or more of sodium carbonate, silicon oxide, calcium oxide, zirconium oxide, lithium oxide, magnesium oxide and ferric oxide; Coal-based solid waste includes one or more of fly ash, coal gangue and bottom ash; The functional oxide plate comprises: a functional oxide, wherein the functional oxide is at least one of silicon oxide, calcium oxide, zirconium oxide, lithium oxide, magnesium oxide and ferric oxide; S2, first subjecting the gradient-doped phase-separated glass plate to surface corrosion treatment, then subjecting it to acid dissolution treatment, washing it to neutrality, and drying it to obtain a gradient porous glass material based on coal-based solid waste, wherein the surface corrosion treatment includes: soaking it in a corrosion solution, and the corrosion solution is an alkaline solution.

2. The preparation method according to claim 1, characterized in that In S1, the method for obtaining the functional oxide flat plate includes: pressing the functional oxide into a shape, and polishing the shape until the surface is smooth, to obtain the functional oxide flat plate.

3. The preparation method according to claim 1, characterized in that In S1, the initial glass plate and the functional oxide plate have the same shape and size.

4. The preparation method according to claim 1, characterized in that In S1, the initial glass plate and the functional oxide plate are attached and pressed together, and the pressure of the force acting on the contact surface of the initial glass plate and the functional oxide plate during pressing is 0.01-0.1 MPa.

5. The preparation method according to claim 1, characterized in that In S2, the surface corrosion treatment includes: immersing in an alkaline solution at 25~150℃ for 0.5~5h.

6. The preparation method according to claim 1, characterized in that In S2, the acid dissolution treatment includes: soaking in an acidic solution at 25-80°C for 2-80 hours.

7. A gradient porous glass material based on coal-based solid waste obtained by the preparation method according to any one of claims 1 to 6.

8. Use of the gradient porous glass material based on coal-based solid waste as claimed in claim 7 as a filtration membrane / emulsification membrane.

9. The use according to claim 8, characterized in that The thickness of the gradient porous glass material based on coal-based solid waste is 0.3~25.0 mm.

10. The use according to claim 8, characterized in that The side with larger pore size of the gradient porous glass material based on coal-based solid waste is used as the front side, and the side with smaller pore size is used as the back side. When the gradient porous glass material is used as a filter membrane / emulsification membrane, the front side is facing upstream of the fluid.

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