Coal-based solid waste-based graded porous glass material and preparation method and application thereof

Abstract

The application discloses a kind of based on coal-based solid waste's gradient porous glass material and its preparation method and application, the preparation method of based on coal-based solid waste's gradient porous glass material includes: initial glass flat plate and functional oxide flat plate are adhered and compacted, heat treatment 1~100 hours under 600~900 ℃, initial glass flat plate and functional oxide flat plate are separated, and gradient doped phase separation glass flat plate is obtained based on initial glass flat plate;Gradient doped phase separation glass flat plate is first subjected to surface corrosion treatment, then subjected to acid dissolution treatment, washed to neutral, dried, to obtain based on coal-based solid waste's gradient porous glass material.The application effectively solves the technical bottleneck existing in traditional uniform porous material, and under the same interception aperture and operating condition, based on coal-based solid waste's gradient porous glass material shows flux improvement compared with homogeneous porous glass material.

Description

TECHNICAL FIELD

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

[0002] Porous glass materials exhibit important application value in the field of membrane separation due to their unique pore structure and excellent physical and chemical properties. However, the preparation process of traditional porous glass materials often relies on high-purity raw materials, resulting in high production costs, which is inconsistent with the current green and low-carbon development concept.

[0003] In recent years, the technical route of preparing porous glass materials from coal-based solid waste as raw materials provides a new idea for solving the above problems. However, the existing porous glass materials are generally uniform porous glass materials, and the traditional uniform porous glass materials have obvious performance limitations in application. In the field of membrane separation, when the fluid contains particles of different sizes, all particles will concentrate on the membrane surface, which is easy to block. In addition, due to the limitation of the pore size distribution, the uniform porous glass material is difficult to balance the retention effect and permeation flux when used as a filter membrane. In the field of membrane emulsification, although the uniform pore size can control the initial size of the droplets to a certain extent, when facing different viscosity dispersed phase or continuous phase systems, a single pore size distribution is difficult to flexibly adjust the droplet formation efficiency and stability, and the uniform pore size is also easy to cause local droplet aggregation and membrane pore blockage during long-term emulsification process.

[0004] Therefore, it is urgent to innovate from the material structure design level, develop porous glass materials with new pore structure, realize the high-value utilization of coal-based solid waste, and break through the technical limitations of traditional separation membrane materials in mass transfer efficiency, separation performance and dispersion performance. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application aims to provide a preparation method of a coal-based solid waste-based gradient porous glass material. The present application establishes a diffusion-phase separation synergistic mechanism, uses coal gangue, fly ash and other coal-based solid wastes as basic raw materials, constructs a borosilicate glass system, and uses 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 application is to provide a coal-based solid waste-based gradient porous glass material obtained by the above preparation method.

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

[0008] The application aims to achieve the above-mentioned purposes through the technical scheme.

[0009] A preparation method of a coal-based solid waste-based gradient porous glass material, comprising the following steps:

[0010] S1, the initial glass flat plate and the functional oxide flat plate are adhered and compressed, heat treated at 600-900 DEG C for 1-100 hours (to make the functional oxide in the functional oxide flat plate gradient diffusion to the initial glass flat plate, at the same time, the initial glass flat plate occurs phase separation), the initial glass flat plate and the functional oxide flat plate are separated, and the gradient doping phase separation glass flat plate is obtained based on the initial glass flat plate;

[0011] The method for obtaining the initial glass flat plate comprises: mixing the coal-based solid waste, quartz sand, boron oxide and auxiliary agent uniformly, melting at 1000-1700 DEG C for 1-5 hours, obtaining the molten glass, pouring and forming the molten glass, and annealing at 500-600 DEG C for 0.5-2 hours, obtaining the initial glass flat plate, and the mass fraction of the coal-based solid waste, quartz sand, boron oxide and auxiliary agent is (1-7):(1-3):(2-5):(1-7), and the auxiliary agent is one or more of sodium carbonate, silicon oxide, calcium oxide, zirconium oxide, lithium oxide, magnesium oxide and diiron trioxide;

[0012] The coal-based solid waste comprises one or more of fly ash, coal gangue and furnace bottom slag;

[0013] The functional oxide flat plate comprises: functional oxide, and the functional oxide is at least one of silicon oxide, calcium oxide, zirconium oxide, lithium oxide, magnesium oxide and diiron trioxide;

[0014] In S1, the method for obtaining the functional oxide flat plate comprises: pressing and forming the functional oxide (powder), and polishing to obtain the functional oxide flat plate.

[0015] In S1, the shape and size of the initial glass flat plate and the functional oxide flat plate are the same.

[0016] In S1, the initial glass flat plate and the functional oxide flat plate are adhered and compressed, and the pressure of the force acting on the contact surface of the initial glass flat plate and the functional oxide flat plate is 0.01-0.1 MPa.

[0017] In S1, the heat treatment at 600-900 DEG C is preferably 10-48 hours.

[0018] S2, the gradient doping phase separation glass flat plate is first subjected to surface corrosion treatment, then subjected to acid dissolution treatment, washed to neutral, dried, and the coal-based solid waste-based gradient porous glass material is obtained, wherein the surface corrosion treatment comprises: soaking in an etching liquid, and the etching liquid is an alkaline solution.

[0019] In S2, the surface corrosion treatment comprises: soaking in an alkaline solution at 25-150 DEG C for 0.5-5 h.

[0020] In the 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.

[0021] In S2, the acid solution treatment comprises: soaking in an acid solution at 25-80 DEG C for 2-80 h.

[0022] In the technical solution, the acid 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 acid solution is 1-6 mol / L.

[0023] In S2, water washing is adopted.

[0024] The coal-based solid waste-based graded porous glass material is prepared by the preparation method.

[0025] In the technical solution, the pore size of the coal-based solid waste-based graded porous glass material gradually increases or gradually decreases along the thickness direction.

[0026] In the technical solution, the porosity of the coal-based solid waste-based graded porous glass material is 30-80%.

[0027] The coal-based solid waste-based graded porous glass material is used as a filter membrane / emulsion membrane.

[0028] In the technical solution, the thickness of the coal-based solid waste-based graded porous glass material is 0.3-25.0 mm.

[0029] In the technical solution, the side with larger pore size of the coal-based solid waste-based graded porous glass material is used as the front side, the side with smaller pore size is used as the back side, and when the graded porous glass material is used as a filter membrane / emulsion membrane, the front side faces the upstream of the fluid.

[0030] Compared with the prior art, the coal-based solid waste-based graded porous glass material has the following beneficial effects:

[0031] 1. The coal-based solid waste-based graded porous glass material of the present application has a graded porous structure. When used as a filtration membrane, the side with larger pore size of the coal-based solid waste-based graded porous glass material is used as the front side, and the side with smaller pore size is used as the back side. The front side is directed towards the upstream of the fluid, and the fluid is first intercepted by the larger particles. As the fluid flows in the filtration membrane, the pore size gradually decreases, and the filtration membrane further intercepts smaller particles or molecules. This "large first, small later" interception mode avoids the problem of all pollutants being concentrated on the membrane surface, reduces the "instantaneous pollution" caused by large particles blocking small pores, and makes the pollutants distributed along the pore size gradient in the membrane rather than accumulated on a single surface, thereby making the fluid flow more uniform in the membrane, weakening the concentration polarization phenomenon (pollutants are enriched on the membrane surface to form a high concentration layer), and reducing the performance degradation of the membrane caused by long-term polarization.

[0032] 2. When used as a filtration membrane, the coal-based solid waste-based graded porous glass material of the present application has a larger pore size on the front side, providing a more unobstructed initial channel for the fluid, reducing the resistance of the fluid entering the membrane interior, and further intercepting smaller pollutants as the fluid flows in the direction of decreasing pore size. While ensuring interception accuracy, the problem of small pores in uniform pore size membranes obstructing fluid flow is avoided, thereby improving flux. The present application balances between interception accuracy and flux, and is particularly suitable for filtering fluids containing complex multi-component pollutants. Traditional uniform pore size membranes need to have smaller pore sizes to achieve high interception accuracy, often at the expense of flux, and need to have larger pore sizes to achieve high flux, which cannot intercept smaller pollutants and reduces interception effect. The present application effectively solves the technical bottleneck of traditional uniform porous materials, and the coal-based solid waste-based graded porous glass material exhibits improved flux compared to homogeneous porous glass materials under the same interception pore size and operating conditions.

[0033] 3. When used as a filtration membrane, the coal-based solid waste-based graded porous glass material of the present application has a gradient distribution of pollutants in the membrane, making the stress on the membrane more uniform, avoiding the problem of membrane pore tearing caused by large particles impacting the small pores on the surface layer, and reducing damage.

[0034] 4. When used as a filtration membrane, the coal-based solid waste-based graded porous glass material of the present application has a larger pore size channel that is more easily penetrated by cleaning liquid, and the pollutants inside the membrane are more easily removed due to their dispersed distribution, resulting in higher regeneration efficiency and better performance after multiple cleanings.

[0035] 5. When the fluid to be filtered contains pollutants of various sizes from large to small (such as sewage containing sand, colloids, and small molecular organic matter), the graded porous structure can selectively intercept different components, and one-step separation can be achieved without the need for multiple filtration equipment, simplifying the process and reducing costs.

[0036] In conclusion, the technical scheme of the present application realizes the collaborative innovation of high-value utilization of coal-based solid waste and pore structure design, and provides a new type of porous glass material with excellent performance for the field of membrane separation. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 SEM of the cross-section bottom position of the coal-based solid waste-based uniform porous glass material prepared in Example 1 at 500 times;

[0038] Figure 2 SEM of the cross-section bottom position of the coal-based solid waste-based uniform porous glass material prepared in Example 1 at 5000 times;

[0039] Figure 3 SEM of the cross-section middle position of the coal-based solid waste-based uniform porous glass material prepared in Example 1 at 500 times;

[0040] Figure 4 SEM of the cross-section middle position of the coal-based solid waste-based uniform porous glass material prepared in Example 1 at 5000 times;

[0041] Figure 5 SEM of the cross-section top position of the coal-based solid waste-based uniform porous glass material prepared in Example 1 at 500 times;

[0042] Figure 6 SEM of the cross-section top position of the coal-based solid waste-based uniform porous glass material prepared in Example 1 at 5000 times;

[0043] Figure 7 SEM of the cross-section bottom position of the coal-based solid waste-based gradient porous glass material prepared in Example 2 at 500 times;

[0044] Figure 8 SEM of the cross-section bottom position of the coal-based solid waste-based gradient porous glass material prepared in Example 2 at 5000 times;

[0045] Figure 9 SEM of the cross-section middle position of the coal-based solid waste-based gradient porous glass material prepared in Example 2 at 500 times;

[0046] Figure 10 SEM of the cross-section middle position of the coal-based solid waste-based gradient porous glass material prepared in Example 2 at 5000 times;

[0047] Figure 11 SEM of the cross-section top position of the coal-based solid waste-based gradient porous glass material prepared in Example 2 at 500 times;

[0048] Figure 12 SEM of the top of the cross-section of the coal-based solid waste derived graded porous glass material prepared in Example 2 at 5000x magnification;

[0049] Figure 13 XCT image of the coal-based solid waste derived graded porous glass material prepared in Example 2;

[0050] Figure 14 SEM of the bottom of the cross-section of the coal-based solid waste derived graded porous glass material prepared in Example 3 at 500x magnification;

[0051] Figure 15 SEM of the bottom of the cross-section of the coal-based solid waste derived graded porous glass material prepared in Example 3 at 5000x magnification;

[0052] Figure 16 SEM of the middle of the cross-section of the coal-based solid waste derived graded porous glass material prepared in Example 3 at 500x magnification;

[0053] Figure 17 SEM of the middle of the cross-section of the coal-based solid waste derived graded porous glass material prepared in Example 3 at 5000x magnification;

[0054] Figure 18 SEM of the top of the cross-section of the coal-based solid waste derived graded porous glass material prepared in Example 3 at 500x magnification;

[0055] Figure 19 SEM of the top of the cross-section of the coal-based solid waste derived graded porous glass material prepared in Example 3 at 5000x magnification;

[0056] Figure 20 Contact angle of the coal-based solid waste derived graded porous glass material prepared in Example 2 before modification with water;

[0057] Figure 21 Contact angle of the coal-based solid waste derived graded porous glass material prepared in Example 2 after modification with water;

[0058] Figure 22 Pore size distribution of the coal-based solid waste derived homogeneous porous glass material prepared in Example 1, and the coal-based solid waste derived graded porous glass materials prepared in Examples 2 and 3;

[0059] Figure 23 Chemical composition of the coal-based solid waste derived homogeneous porous glass material prepared in Example 1, and the coal-based solid waste derived graded porous glass materials prepared in Examples 2 and 3;

[0060] Figure 24Glass transition temperature of the coal-based solid waste-based homogeneous porous glass material prepared in Example 1, the coal-based solid waste-based graded porous glass material prepared in Example 2 and Example 3. DETAILED DESCRIPTION

[0061] The technical solutions of the present application are further illustrated below in combination with specific examples.

[0062] The raw material information involved in the following examples is as follows:

[0063]

[0064] The composition (in mass percentage) of the fly ash purchased from Shangdu Power Generation Co., Ltd. in Inner Mongolia is as follows: SiO2 content: 40.17%, Al2O3 content: 17.5%, SO3 content: 10.78%, Fe2O3 content: 10.86%, CaO content: 9.05%, MgO content: 5.74%, K2O content: 2.30%, Na2O content: 1.44%, and other (organic substances and reducing substances, etc.): 2.16%. Since the fly ash raw material contains a small amount of organic substances and reducing substances, if these substances are not removed in advance, they will have a double negative effect: on the one hand, in the subsequent high-temperature melting process, their decomposition or oxidation will cause additional bubble generation, leading to melt spitting; on the other hand, their chemical action will cause significant corrosion damage to the platinum-rhodium alloy crucible. Therefore, the purchased fly ash is calcined at 900°C for 10 hours to remove the organic substances and reducing substances contained therein before use.

[0065] Example 1

[0066] A preparation method of a coal-based solid waste-based homogeneous porous glass material (homogeneous porous glass material), comprising the following steps:

[0067] S1, mix the coal-based solid waste (fly ash), quartz sand, boron oxide and additives uniformly, place them in a platinum-rhodium alloy crucible, melt them in a high-temperature furnace at 1400°C for 2 hours to obtain molten glass, pour and shape the molten glass, anneal it at 500°C for 0.3h, cut and polish it to obtain an initial glass flat plate with a size of 20 mm x 10 mm x 2 mm, heat treat the initial glass flat plate in a low-temperature furnace at 700°C for 24 hours to perform phase separation, and obtain a phase-separated glass flat 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 fraction, and the additive is a mixture of calcium oxide and sodium carbonate, and the ratio of calcium oxide and sodium carbonate is 2:1 by mass fraction;

[0068] S2, the phase separation glass flat is first subjected to surface corrosion treatment to remove the surface dense silicon oxide layer (0.5 h of immersion in a 1 mol / L NaOH aqueous solution at 30°C for surface corrosion treatment), and then subjected to acid dissolution treatment to remove the acid-soluble phase in the phase separation glass flat (24 h of immersion in an acid solution at 30°C for acid dissolution treatment, the acid solution is hydrochloric acid, the concentration of HCl in the hydrochloric acid is 1 mol / L), washed with water to neutral (pH=7), dried at 60°C for 30 min, to obtain a coal-based solid waste-based uniform porous glass material with a thickness of 2.0 mm.

[0069] The cross-sectional microstructure of the coal-based solid waste-based uniform porous glass material prepared in Example 1 was observed by scanning electron microscopy, as shown in FIG. 1, wherein, Figures 1-6 Figure 1 is an SEM of the bottom position of the cross-section of the coal-based solid waste-based uniform porous glass material at 500 times, Figure 2 Figure 1 is a local magnified view (SEM of the bottom position of the cross-section of the coal-based solid waste-based uniform porous glass material at 5000 times), Figure 3 Figure 4 is an SEM of the middle position of the cross-section of the coal-based solid waste-based uniform porous glass material at 500 times, Figure 3 Figure 5 is a local magnified view (SEM of the middle position of the cross-section of the coal-based solid waste-based uniform porous glass material at 5000 times), Figure 6 Figure 5 is an SEM of the top position of the cross-section of the coal-based solid waste-based uniform porous glass material at 500 times, and Figures 1-6

[0070] Example 2

[0071] A preparation method of a coal-based solid waste-based gradient porous glass material, comprising the following steps:

[0072] ​​​​​​S1. The initial glass plate and the functional oxide plate are bonded and pressed together at room temperature (the initial glass plate and the functional oxide plate are placed horizontally with the functional oxide plate above the initial glass plate, and the pressure (including the weight of the functional oxide plate itself) is adjusted by weights so that the pressure at the contact surface of the initial glass plate and the functional oxide plate is 0.03 MPa during pressing). The plate is then heat-treated in a low-temperature furnace at 700℃ for 24 hours to allow the functional oxides in the functional oxide plate to diffuse gradually into the initial glass plate. Simultaneously, the initial glass plate undergoes phase separation. 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. The method for obtaining the initial glass plate includes: mixing coal-based solid waste (fly ash), quartz sand, boron oxide, and additives until homogeneous, placing the mixture in a platinum-rhodium alloy crucible, and melting it in a high-temperature furnace at 1400℃ for 2 hours to obtain molten glass. The molten glass is then cast into a shape, annealed at 500℃ for 0.3 hours, and cut and polished to obtain a size of 20 mm × 10 mm × 2. The initial glass plate of mm, by mass parts, has coal-based solid waste (fly ash), quartz sand, boron oxide and additives in the ratio of 5:2:3:3, and the additives are a mixture of calcium oxide and sodium carbonate, by mass parts, with calcium oxide and sodium carbonate in the ratio of 2:1.

[0073] The method for obtaining functional oxide plates includes: placing functional oxide (powder) in the mold of a Miqi manual tablet press (purchased from Hunan Changsha Miqi Instrument Equipment Co., Ltd.) at room temperature, setting the tablet pressing parameters: pressure 30MPa, holding time 50s, pressing it into shape, and polishing it until the surface is flat and smooth to obtain a functional oxide plate with a size of 20 mm × 10 mm × 2 mm, wherein the functional oxide is aluminum oxide;

[0074] S2, the gradient-doped phase-separated glass plate is first subjected to surface etching treatment to remove the dense silicon oxide layer on the surface (immersion in sodium hydroxide aqueous solution at 30℃ for 0.5 h for surface etching treatment, the concentration of NaOH in the sodium hydroxide aqueous solution is 1 mol / L), and then immersed in an acidic solution at 30℃ for 24 h for acid dissolution treatment, the acidic solution is hydrochloric acid (the concentration of HCl in hydrochloric acid is 1 mol / L), washed with water until neutral (pH=7), and dried at 60℃ for 30 min to obtain a gradient porous glass material based on coal-based solid waste with dimensions of 20 mm×10 mm×2 mm.

[0075] The cross-sectional micromorphology of the graded porous glass material based on coal-based solid waste prepared in Example 2 was observed using a scanning electron microscope, such as... Figures 7-12 As shown, where, Figure 7SEM of the bottom position of the cross-section of the coal-based solid waste-gradual porous glass material (500 times), Figure 8 Figure 7 partial enlargement (SEM of the bottom position of the cross-section of the coal-based solid waste-gradual porous glass material (5000 times), Figure 9 SEM of the middle position of the cross-section of the coal-based solid waste-gradual porous glass material (500 times), Figure 10 Figure 9 partial enlargement (SEM of the middle position of the cross-section of the coal-based solid waste-gradual porous glass material (5000 times), Figure 11 SEM of the top position of the cross-section of the coal-based solid waste-gradual porous glass material (500 times), Figure 12 Figure 11 partial enlargement (SEM of the top position of the cross-section of the coal-based solid waste-gradual porous glass material (5000 times). It can be seen from Figures 7-12 that the pore structure is curved cylindrical and interwoven, extending from the contact surface of the initial glass flat plate and the functional oxide flat plate to the distal end, and the pore size of the coal-based solid waste-gradual porous glass material shows a gradually increasing trend, because Example 2 uses alumina as the functional oxide, which inhibits phase separation.

[0076] The three-dimensional structure of the coal-based solid waste-gradual porous glass material prepared in Example 2 was determined by X-ray tomography technology (XCT), and the test results are shown in the XCT image of Figure 13 , the pore size gradually changes along the x-axis (i.e. the thickness direction of the coal-based solid waste-gradual porous glass material), especially at the contact interface near the functional oxide flat plate, the pore size is obviously smaller than the end away from the functional oxide flat plate. The pore size of the coal-based solid waste-gradual porous glass material is uniformly distributed on any one of the surfaces perpendicular to the thickness direction.

[0077] Example 3

[0078] A preparation method of a coal-based solid waste-gradual porous glass material, which is basically the same as Example 2, except that the functional oxide is calcium oxide.

[0079] The cross-sectional microstructure of the coal-based solid waste-gradual porous glass material prepared in Example 3 was observed by scanning electron microscope, as shown in Figures 14-19 , wherein, Figure 14 SEM of the bottom position of the cross-section of the coal-based solid waste-gradual porous glass material (500 times), Figure 15 Figure 14 ​​​​a partial enlarged view (SEM of the middle position of the cross section of the coal-based solid waste derived graded porous glass material at 5000 times magnification), Figure 16 a SEM of the middle position of the cross section of the coal-based solid waste derived graded porous glass material at 500 times magnification, Figure 17 a partial enlarged view (SEM of the middle position of the cross section of the coal-based solid waste derived graded porous glass material at 5000 times magnification), Figure 16 a partial enlarged view (SEM of the middle position of the cross section of the coal-based solid waste derived graded porous glass material at 5000 times magnification), Figure 18 a SEM of the top position of the cross section of the coal-based solid waste derived graded porous glass material at 500 times magnification, Figure 19 a partial enlarged view (SEM of the top position of the cross section of the coal-based solid waste derived graded porous glass material at 5000 times magnification), Figure 18 It can be seen from Figures 14-19 that the pore structure is curved cylindrical and interwoven, extending from the contact surface of the initial glass flat plate and the functional oxide flat plate to the distal end, and the pore size of the coal-based solid waste derived graded porous glass material presents a gradually decreasing trend, because Example 3 uses calcium oxide as the functional oxide, which promotes phase separation.

[0080] The coal-based solid waste derived graded porous glass material prepared in Example 2 was calcined in a muffle furnace at 500°C for 2 hours, cooled to room temperature, and then ultrasonically treated in deionized water for 0.5 hours (the frequency of the ultrasonic treatment was 40 kHz, and the power of the ultrasonic treatment was 100 W), and then immersed in a silane coupling agent aqueous solution for modification: ultrasonic treatment for 2 hours under a vacuum degree of 0.08 MPa (the frequency of the ultrasonic treatment was 40 kHz, and the power of the ultrasonic treatment was 100 W), and finally, coupling reaction in a constant temperature oven at 120°C for 4 hours, the concentration of the silane coupling agent in the silane coupling agent 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 derived graded porous glass material before and after modification with water were measured by a contact angle measuring instrument, the contact angle of the coal-based solid waste derived graded porous glass material before modification with water is shown in Figure 20 , and the contact angle of the coal-based solid waste derived graded porous glass material after modification with water is shown in Figure 21 .

[0081] It can be seen from Figure 20 and Figure 21 that the coal-based solid waste derived graded porous glass material before modification is extremely hydrophilic (θ=0 C.A. o ), and a hydrophobic surface can be obtained after modification by the silane coupling agent (θ=138 C.A. o ​​The surface of the graded porous glass material based on coal-based solid waste is rich in Si-OH groups, thus exhibiting hydrophilicity. 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 tunable wetting properties, which significantly expands the application scope of the material.

[0082] The pore size distribution of the material was determined using a mercury porosimeter, and the test results are as follows: Figure 22 As shown, the material is one of the uniform porous glass material based on coal-based solid waste prepared in Example 1, and the graded porous glass material based on coal-based solid waste prepared in Examples 2 and 3.

[0083] 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 graded porous glass material based on coal-based solid waste prepared in Example 2 is 2.74 μm and the porosity is 68.77%; and the average pore size of the graded 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 gradient porous glass material based on coal-based solid waste prepared in Example 2 is shifted towards smaller pore sizes compared to the uniform porous glass material based on coal-based solid waste. The overall pore size distribution of the gradient porous glass material based on coal-based solid waste prepared in Example 3 is shifted towards larger pore sizes compared to the uniform porous glass material based on coal-based solid waste.

[0084] The pore structure in SEM images was measured using ImageJ software to obtain the cut-off pore sizes of the uniform porous glass material based on coal-based solid waste prepared in Example 1, and the graded porous glass materials based on coal-based solid waste prepared in Examples 2 and 3, respectively. Specifically, the cut-off pore size of the uniform porous glass material based on coal-based solid waste prepared in Example 1 was 3.30 μm; the cut-off pore size at the bottom of the cross-section of the graded porous glass material based on coal-based solid waste prepared in Example 2 was 0.95 μm; and the cut-off pore size at the top of the cross-section of the graded porous glass material based on coal-based solid waste prepared in Example 3 was 3.30 μm.

[0085] The material was pulverized and dispersed evenly, and then its chemical composition was determined using X-ray fluorescence spectrometry (XRF). The test results are as follows: Figure 23 As shown, the material is one of the phase-separated glass plates prepared by S1 in Example 1 and the gradient-doped phase-separated glass plates prepared by S1 in 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 interior of 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 interior of the initial glass plate in Example 3. That is, by controlling the diffusion behavior of the functional oxide after contact with the initial glass plate (matrix glass), and utilizing the differences in composition at the contact surface and the asynchronous phase separation behavior, the microstructure of the gradient porous glass material can be precisely controlled.

[0086] The glass transition temperature of the material was determined using a differential scanning calorimeter, and the test results are as follows: 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 graded porous glass material based on coal-based solid waste prepared in Examples 2 and 3. Figure 24 It is known that the glass transition temperature of the uniform porous glass material based on coal-based solid waste prepared in Example 1 is 640℃; the glass transition temperature of the graded porous glass materials based on coal-based solid waste prepared in Examples 2 and 3 is also 640℃. The graded porous glass material based on coal-based solid waste of the present invention exhibits excellent temperature resistance.

[0087] 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 circular membranes with a diameter of 10.0 mm and used as filter membranes. Flux tests were conducted using a cross-flow filtration system (manufacturer: Baoding Rongbai Constant Flow Pump Manufacturing Co., Ltd., model: LSP02-2DY). During the test, the side with the 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 the smaller pore size as the back side, with the front side facing 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 conducted under gravity and atmospheric pressure according to the instructions of the cross-flow filtration system. The time required for 5 mL of deionized water to completely permeate through the filter membrane was recorded. Each experiment was repeated 3 times, and the average of the 3 experiments was used as the permeation time for calculation. The permeation time and flux values ​​are shown in Table 1. The flux (… L The formula for calculating / (m²·h) is:

[0088] Flux = V / ( A × t )×3600,

[0089] in,V = 0.005L, A = 0.0000785m 2 , t is the permeation time (s).

[0090] Table 1

[0091]

[0092] As can be seen from Table 1, under the condition of the same cut-off aperture (the cut-off aperture of the smaller side of the coal-based solid waste-based graded porous glass material is the same as that of the uniform porous glass material), the flux of the coal-based solid waste-based graded porous glass material prepared in Example 3 is 1.5 times that of Example 1, which confirms the significant effect of the gradient aperture structure on improving the mass transfer performance of the membrane material.

[0093] The present application exemplarily presents the application effect of the coal-based solid waste-based graded porous glass material as a filtration membrane, and according to the similarity of the application principle, it can be known that the coal-based solid waste-based graded porous glass material as an emulsification membrane can also achieve good technical effects. The aperture of the coal-based solid waste-based graded porous glass material is in 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 emulsion membrane pore, thereby realizing a significant increase in the dispersed phase flux under the same operating pressure. At the same time, the tapered pore structure is beneficial to focusing and pre-accelerating the dispersed phase fluid, reducing the flow dead zone and incomplete internal pore wetting phenomenon, effectively improving the proportion and utilization efficiency of the emulsion membrane surface activation hole. In addition, the larger aperture at the inlet reduces the risk of membrane hole blockage, enhances the stability and anti-pollution ability of the emulsification process. This structural design fundamentally solves the hydraulic bottleneck problem of the homogeneous membrane in high flux application under the premise of ensuring the monodispersity of the emulsion.

[0094] The above has exemplarily described the present application, it should be explained that, without departing from the core of the present application, any simple deformation, modification or other equivalent replacement which can not cost creative labor of the person skilled in the art falls into the protection scope of the present application.

Claims

1. Use of a coal-based solid waste-based graded porous glass material as a filtration membrane, characterized in that, The pore diameter of the coal-based solid waste-based graded porous glass material gradually increases or gradually decreases along the thickness direction. When the coal-based solid waste-based graded porous glass material is used as a filter membrane, the side with the larger pore diameter is used as the front side, and the side with the smaller pore diameter is used as the back side. The front side faces the upstream of the fluid. The preparation method of the coal-based solid waste-based graded porous glass material comprises the following steps: S1, the initial glass flat plate and the functional oxide flat plate are adhered and compressed, and heat treated at 600-900 DEG C for 1-100 hours, the initial glass flat plate and the functional oxide flat plate are separated, and the gradient doped phase separation glass flat plate is obtained based on the initial glass flat plate, the shape and size of the initial glass flat plate and the functional oxide flat plate are the same, the method for obtaining the functional oxide flat plate comprises: the functional oxide is pressed into shape, polished to smooth surface, and the functional oxide flat plate is obtained, the functional oxide is calcium oxide or aluminum oxide; The method for obtaining the initial glass flat plate comprises: mixing the coal-based solid waste, quartz sand, boron oxide and auxiliary agent uniformly, melting at 1000-1700 DEG C for 1-5 hours, obtaining molten glass, pouring into shape, and annealing at 500-600 DEG C for 0.5-2 hours, obtaining the initial glass flat plate, the mass fraction of the coal-based solid waste, quartz sand, boron oxide and auxiliary agent is (1-7):(1-3):(2-5):(1-7), and the auxiliary agent is one or more of sodium carbonate, silicon oxide, calcium oxide, zirconium oxide, lithium oxide, magnesium oxide and ferric oxide; The coal-based solid waste comprises one or more of fly ash, coal gangue and furnace bottom slag; S2, the gradient doped phase separation glass flat plate is first subjected to surface corrosion treatment, then subjected to acid dissolution treatment, washed to neutral, dried, and the coal-based solid waste-based graded porous glass material is obtained, wherein the surface corrosion treatment comprises: soaking in an etching liquid, and the etching liquid is an alkaline solution.

2. Use according to claim 1, characterized in that, In S1, the initial glass flat plate and the functional oxide flat plate are adhered and compressed, and the pressure of the force acting on the contact surface of the initial glass flat plate and the functional oxide flat plate is 0.01-0.1 MPa.

3. Use according to claim 1, characterized in that, In S2, the surface corrosion treatment comprises: soaking in an alkaline solution at 25-150 DEG C for 0.5-5 hours.

4. Use according to claim 1, characterized in that, In S2, the acid dissolution treatment comprises: soaking in an acid solution at 25-80 DEG C for 2-80 hours.

5. The use according to claim 1, characterized in that, The thickness of the coal-based solid waste-based graded porous glass material is 0.3-25.0 mm.

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