Coal coke membrane

Abstract

The utility model provides a coal coke membrane which adopts coal coke and biomass charcoal as main raw materials, is prepared through pyrolysis and forming processes, and has a porous structure and efficient liquid filtering performance. And the mass ratio of the coal coke to the biomass charcoal can be regulated and controlled so as to optimize the pore size distribution and the filtering efficiency. The membrane is doped with a non-metallic mineral material so as to enhance the adsorption capacity and the separation efficiency. The membrane exhibits an impurity removal rate of at least 90% when treating cotton spinning waste liquid. The preparation process comprises the steps of raw material mixing, binder adding, pyrolysis treatment, cooling smashing and forming. The coal coke membrane has high stability, selectivity, permeability and mechanical strength, provides an efficient and stable novel membrane material for industrial wastewater treatment, and has a remarkable application prospect.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of coal coke membrane, specifically, relate to a coal coke membrane. BACKGROUND

[0002] With the in-depth development of China's industrialization, the influence of industry on water resources is a complex and multi-faceted problem. The random discharge of industrial wastewater not only brings an unbearable burden to the environment, but also pollutes domestic water, exacerbating the problem of water scarcity. Therefore, it is particularly important to reduce industrial pollution. The pollution of water resources in cotton textile mills mainly comes from the large amount of wastewater generated during the production process. According to statistics, the Ministry of Environmental Protection found that the textile industry discharged 19.61 million tons of wastewater per year, accounting for a major part of total industrial wastewater discharge. If not properly treated, suspended solids, oils, fibers, surfactants and various dyes can be discharged into water bodies, causing serious pollution to water quality. Secondly, management is also an important factor. Many printing and dyeing enterprises adopt the mode of building wastewater treatment facilities separately and dispersing layout, which brings great difficulty to management. Environmental protection management departments need to monitor the discharge water quality of each printing and dyeing enterprise one by one, and the total wastewater treatment cost of enterprises is also high. Therefore, it has become an important task to effectively treat the wastewater of cotton textile mills and reduce their impact on water resources.

[0003] Membrane separation technology has become one of the important means for treating cotton spinning wastewater. However, the existing membrane materials have many problems in treating cotton spinning wastewater, and cannot meet the needs of efficient, stable and durable treatment. Although traditional organic membranes have certain filtration performance, they have obvious shortcomings in stability, selectivity, permeability, separation capacity and mechanical strength. The main shortcomings of existing technologies in use are as follows:

[0004] 1. Poor stability: Traditional organic membranes are prone to degradation or deformation in high temperature, strong acid and alkali harsh environments, resulting in short service life of the membranes and high maintenance cost.

[0005] 2. Insufficient selectivity and permeability: The pore size distribution of existing organic membranes is uneven, which can easily cause pore size to be too large or too small, affecting the selectivity and filtration efficiency of specific pollutants.

[0006] 3. Limited separation capacity: The separation capacity of traditional organic membranes is limited when treating complex composition of cotton spinning wastewater, making it difficult to effectively remove organic pollutants.

[0007] 4. Insufficient mechanical strength: Due to the characteristics of organic materials, traditional organic membranes are prone to breakage during long-term operation, affecting filtration effect and service life. Therefore, we propose a coal coke membrane. Utility Model Content

[0008] The purpose of this utility model is to address the problems raised in the existing background technology. To achieve the above-mentioned purpose, this utility model provides the following technical solution: a coal coke membrane, comprising a coal coke base layer, a biochar layer attached to the coal coke base layer, a dopant layer disposed on the biochar layer, and a thermosetting phenolic resin layer disposed on the dopant layer.

[0009] As a preferred technical solution of this utility model, the dopant layer is made of non-metallic mineral material.

[0010] As a preferred technical solution of this utility model, the non-metallic mineral material includes vermiculite and sepiolite.

[0011] As a preferred embodiment of this invention, the thermosetting phenolic resin layer is provided with a phenolic resin binder.

[0012] As a preferred technical solution of this utility model, the pore size of the coal coke base layer is distributed between 0.1 micrometers and 10 micrometers.

[0013] As a preferred technical solution of this utility model, the thickness of the coal and coke base layer ranges from 0.1 mm to 2 mm.

[0014] As a preferred technical solution of this utility model, the coal and coke base layer is in the shape of a flat plate, a tubular shape, or a hollow fiber shape.

[0015] Compared with existing technologies, the beneficial effects of this invention are as follows: By combining the coal coke base layer and the biochar layer, the coal coke membrane has a uniform pore size distribution and high permeability, which can effectively filter and adsorb organic pollutants in cotton textile wastewater. The addition of coal coke significantly improves the hardness and grindability of the membrane, making it more durable and less prone to damage during operation, thereby extending the membrane's service life.

[0016] The use of a thermosetting phenolic resin layer further enhances the membrane's mechanical strength and provides excellent stability, especially under high-temperature and chemically corrosive environments. By controlling the pore size distribution of the coal coke substrate between 0.1 μm and 10 μm, the membrane can efficiently separate impurities of different particle sizes, improving the separation effect on organic matter. The dopant layer, made of non-metallic mineral materials, further enhances the membrane's adsorption capacity and separation efficiency. The thickness of the coal coke substrate ranges from 0.1 mm to 2 mm, making it suitable for filtration needs in various application scenarios.

[0017] The membrane can be flat, tubular, or hollow fiber in shape, offering flexible design options to suit the needs of different filtration systems. This membrane design utilizes the high specific surface area and small pore volume of the biochar layer, combined with the properties of coal char, to achieve highly selective and permeable filtration, effectively removing contaminants from cotton textile wastewater. The use of inorganic membrane materials, including coal char and biochar, endows the membrane with higher chemical and thermal stability, enabling it to maintain high-efficiency filtration performance even under extreme conditions.

[0018] By adjusting the composition and ratio of the dopant layer and the thermosetting phenolic resin layer, the membrane performance can be further optimized to meet the treatment needs of different types of wastewater, demonstrating broad application potential. Coal coke membranes exhibit higher efficiency in treating cotton textile wastewater, achieving more efficient pollution removal with lower energy consumption and material costs. Attached Figure Description

[0019] Fig. 1 A schematic diagram of the layered phase structure provided by this utility model;

[0020] Fig. 2 A schematic diagram illustrating the change of absorbance of cotton textile waste liquid with wavelength provided by this utility model;

[0021] Fig. 3 A schematic diagram of the standard curve for cotton textile waste liquid provided by this utility model.

[0022] The image shows:

[0023] 1. Coal and coke base layer; 2. Biochar layer; 3. Dopant layer; 4. Thermosetting phenolic resin layer. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model.

[0025] Therefore, the following detailed description of the embodiments of this utility model is not intended to limit the scope of the claimed utility model, but merely illustrates some embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model. It should be noted that, in the absence of conflict, the embodiments and features and technical solutions in the embodiments of this utility model can be combined with each other. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] Example 1: Please refer to Figs. 1-3 A coal coke membrane includes a coal coke base layer 1, a biochar layer 2 attached to the coal coke base layer 1, a dopant layer 3 disposed on the biochar layer 2, and a thermosetting phenolic resin layer 4 disposed on the dopant layer 3. The coal coke base layer 1 is in the shape of a flat plate, a tubular shape, or a hollow fiber shape.

[0027] The dopant layer 3 is made of non-metallic mineral materials. These non-metallic mineral materials include vermiculite and sepiolite.

[0028] The thermosetting phenolic resin layer 4 is provided with phenolic resin adhesive.

[0029] The pore size of the coal and coke base layer 1 ranges from 0.1 micrometers to 10 micrometers. The thickness of the coal and coke base layer 1 ranges from 0.1 millimeters to 2 millimeters.

[0030] Coal-coke membranes are mainly used for the separation of substances in cotton textile wastewater. Their working principle is based on the characteristics of each layer of materials and their synergistic effect. Structurally, it consists of a coal-coke base layer 1, a biomass char layer 2, a dopant layer 3, and a thermosetting phenolic resin layer 4. The layers work together to ensure that the membrane has a certain strength and toughness while improving the membrane's separation capacity and separation rate.

[0031] Coal and coke substrate 1: Feasibility basis for membrane fabrication: As a product of blast furnace coking, the physicochemical properties of coal and coke change during pyrolysis. With increasing temperature, the number of pores on the surface of the coal and coke initially increases and then decreases; the specific surface area and pore volume initially increase and then decrease, reaching their maximum values ​​at approximately 1100℃. Simultaneously, the hydrogen content in the coal and coke gradually decreases, while the carbon-to-hydrogen ratio gradually increases. The carbon content and calorific value initially increase and then slowly decrease. Utilizing these characteristics, by controlling the pore size changes during coal and coke pyrolysis, a pore size distribution between 0.1 micrometers and 10 micrometers, and a thickness range of 0.1 millimeters to 2 millimeters, can be obtained to produce a membrane suitable for filtering cotton textile wastewater. Its flat, tubular, or hollow fiber shape can be selected according to different application scenarios to meet various filtration requirements.

[0032] Filtration principle: The porous structure of the coal and coke base layer 1 can initially intercept larger particles in the cotton textile waste liquid, playing a coarse filtration role and laying the foundation for subsequent fine separation.

[0033] Biochar Layer 2: Material Characteristics: Biochar, with its excellent physicochemical properties suitable for separation technologies, such as large specific surface area, small pore volume, and high adsorption capacity, has become a commonly used material in membrane separation technology. Here, cotton stalks from southern Xinjiang were selected and calcined in a muffle furnace at a programmed temperature of 650℃ for 4 hours to produce the biochar.

[0034] Working principle: The biomass carbon layer 2 attached to the coal and coke base layer 1 uses its large specific surface area and high adsorption capacity to adsorb small molecule organic matter and pigments in the cotton textile wastewater after preliminary filtration by the coal and coke base layer 1, further improving the membrane separation capacity and playing the role of fine filtration while retaining the separation function of traditional membrane technology.

[0035] Dopant layer 3: Material selection criteria: Dopant layer 3 uses vermiculite and sepiolite non-metallic mineral materials, which are widely distributed and have unique pore structures, specific surface areas and adsorption capabilities.

[0036] Working principle: These non-metallic mineral materials, as modifiers for coal coke membranes, can improve the membrane's microstructure and surface properties. Their unique pore structure increases the internal channels of the membrane, improving the material transport efficiency; the increased specific surface area helps to increase the contact area between the membrane and the substances to be separated, thereby enhancing adsorption and separation effects and further improving the membrane's separation efficiency.

[0037] Thermosetting phenolic resin layer 4: Modification function: The main purpose of using thermosetting phenolic resin to modify the coal coke film is to improve the toughness and hardness of the coal coke.

[0038] Working principle: The phenolic resin binder in the thermosetting phenolic resin layer 4 firmly bonds the various layers together to form a whole, increasing the membrane's strength and making it less prone to breakage and damage during use. Simultaneously, adding an appropriate amount of phenolic resin can appropriately increase the pore size of the coal coke membrane, thereby improving the membrane's separation rate and increasing processing efficiency while ensuring the membrane's separation effect.

[0039] The coal and coke base layer 1 serves as the basic structure, providing initial filtration and support. The biochar layer 2 then performs fine adsorption and separation on top of this. The dopant layer 3 modifies the membrane's structure and performance, improving separation efficiency. The thermosetting phenolic resin layer 4 enhances the membrane's strength and separation rate. These layers work together synergistically, enabling the coal and coke membrane to achieve highly efficient separation in cotton textile wastewater.

[0040] Example 2: A raw material for a coal coke membrane, with biochar as the main raw material and coal coke as the auxiliary raw material. Coal coke, as a product of blast furnace coking, plays an important role in the coal chemical industry. Different types of coal coke will exhibit different physicochemical properties during combustion reactions, such as ash content, specific surface area, and pore structure. During the thermal decomposition of coal coke, as the temperature increases, the number of pores on the surface of coal coke will first increase and then decrease. The specific surface area and pore structure volume will also show a trend of first increasing and then decreasing with temperature. When the pyrolysis temperature reaches about 1100℃, these indicators will reach their maximum values, and the hydrogen content (H) in coal coke will gradually decrease, while the ratio of carbon (C) to hydrogen (n(C):n(H)) will gradually increase

[14] . In addition, the carbon content and calorific value in coal coke will also show a trend of first increasing and then slowly decreasing. Due to the physicochemical properties of these coal cokes during thermal decomposition, the feasibility of using coal coke as a membrane raw material is determined. We can control the change in pore size during coal coke decomposition to obtain a suitable membrane for filtering cotton textile waste liquid.

[0041] The biochar is a commonly used material in membrane separation technology. It has excellent physicochemical properties suitable for separation technology, such as large specific surface area, small pore volume and high adsorption capacity. It is made by selecting cotton stalks from southern Xinjiang and burning them in a muffle furnace at a programmed temperature of 650℃ for 4 hours. As part of the main raw materials, it retains the traditional membrane technology and ensures that the membrane has a certain separation capacity. Combined with the advantages of coal coke, the separation capacity of the membrane can be improved [15-19].

[0042] Different types of dopants have varying effects on the separation efficiency of the membrane. For example, vermiculite and sepiolite are both non-metallic mineral materials with wide distribution. Due to their unique pore structure, specific surface area, and adsorption capacity, they can be used as modifiers for coal coke membranes to improve separation efficiency.

[0043] The thermosetting phenolic resin was used in this experiment to modify the coal coke membrane. Since the main purpose was to improve the toughness and hardness of the coal coke, adding an appropriate amount of thermosetting phenolic resin could not only maintain the separation effect of the prepared coal coke membrane, but also increase the strength of the membrane. In addition, adding an appropriate amount of phenolic resin could appropriately increase the pore size of the coal coke membrane, thereby improving the membrane separation rate.

[0044] Experimental example:

[0045] Instruments and equipment used in the experiment

[0046] All instruments used in the process from film preparation to characterization.

[0047]

[0048] Experimental steps

[0049] The experimental process was divided into three processes: film preparation by mixing coal char and biomass char; film preparation by mixing coal char, biomass char, and thermosetting phenolic resin; and film preparation by mixing coal char and biomass char, followed by secondary processing to introduce thermosetting phenolic resin.

[21] The other added hybrid agents and pore-forming agents were all based on the following three sets of experiments. [22-25]

[0050] Coal coke and biochar mixed for membrane fabrication

[0051] 1. Coal coke lumps are ground and sieved to obtain coal coke powder;

[0052] 2. Coal coke powder and carbon powder are thoroughly mixed, and ethylene glycol is used as a binder to obtain coal coke matrix carbon powder. The ratio of biochar to coal coke is 1:1, 1:2, 1:2.5, 1:3, 1:3.5, and 1:4.

[0053] 3. The coal coke matrix carbon powder mixture is placed in a drying oven for heat curing treatment. The resulting cured coal coke matrix primary plate film is ground again and a certain proportion of coal coke powder is added. The amount of this powder is 40% of the amount of coal coke mixed with carbon powder. Take 3g of the mixed powder and add a certain amount of dopant zinc nitrate ZN, generally 0.375g. Use an appropriate amount of ethylene glycol as a binder again, press it into a cake shape using a mold, and heat cure it again in a drying oven to obtain the precursor film.

[0054] 4. Place the precursor membrane into a muffle furnace and further carbonize it under the set parameters;

[0055] 5. The prepared membrane is wrapped in tin foil into a funnel shape to prevent water leakage, forming a membrane pool. The bottom of the funnel is open to allow the cotton textile waste liquid to flow down through filtration. The absorbance of the filtrate is measured by a UV-Vis spectrophotometer.

[0056] This experiment is referred to as Experiment 1.

[0057] Coal biochar and phenolic resin mixed for membrane preparation

[0058] 1. Consistent with the experiment, the coal coke was crushed and sieved.

[0059] 2. Coal char and thermosetting phenolic resin were mixed in a 1:1 ratio to obtain a mixed powder. The thoroughly mixed coal char phenolic resin was then mixed with biochar powder. The biochar to coal char phenolic resin mixtures in ratios of 1:1, 1:3, 1:4, 1:5, and 1:6 were subjected to thermosetting treatment. The resulting mixed matrix coal char was then added back into the coal char phenolic resin mixture. The amount of coal char phenolic resin mixture added back was 40% of the amount added in the first processing. Subsequent procedures were the same as in the previous experiment. This experiment is designated as Experiment Two.

[0060] Phenolic resin is added during secondary processing

[0061] 1. The coal and coke are crushed and sieved.

[0062] 2. Biochar powder and coal coke powder are thoroughly mixed to obtain coal coke matrix char powder. The ratio of biochar to coal coke is 1:1, 1:2, 1:3, 1:4, 1:5, and 1:6.

[0063] 3. The coal-coke matrix carbon powder mixture was placed in a drying oven for heat curing. The resulting cured coal-coke matrix nascent film was then ground again and a certain proportion of the coal-coke phenolic resin mixture from Experiment 2 was added. The amount of coal-coke phenolic resin mixture added was 40% of the amount of coal-coke in one processing step. Subsequent procedures were the same as in the experiment. This experiment is designated as Experiment 3.

[0064] Experimental Precautions

[0065] Improper operation during membrane fabrication can affect membrane quality and the success of membrane formation. Appropriate improvements to experimental procedures can increase membrane fabrication efficiency and success rate. For example, when adding ethylene glycol as a binder, it is necessary to constantly monitor whether the solid powder reaches a "brown sugar" consistency; it can be added in small amounts multiple times. When using a muffle furnace for final carbonization, because the muffle furnace cannot remove residual oxygen, the membrane may be oxidized at high temperatures, resulting in excessively large pores and loss of separation performance. Therefore, a small amount of flammable material, such as paper towels or sawdust, can be placed in the crucible containing the membrane.

[0066] Preparation of standard solution for cotton textile waste liquid

[0067] Take 50 ml of the original cotton textile waste liquid and mix it evenly with 250 ml of pure water to obtain a cotton textile waste liquid standard solution with a volume ratio of 1:5. Seal and store for later use.

[0068] Plotting the standard curve

[0069] Using pure water as a blank control, a standard solution of cotton textile waste liquor mixed with pure water at a ratio of 1:5 was placed in a UV1700PC UV-Vis spectrophotometer. The absorbance of the standard solution was measured every 2 nm within the wavelength range of 250-350 nm. The absorbance was zeroed using the blank control each time the wavelength was changed. The absorbance of the standard solution varied with the wavelength of light, thus identifying the wavelength of maximum absorption. The results are as follows. Fig. 2 As shown, the maximum absorbance is at a wavelength of 290 nm, i.e., the maximum absorption wavelength is 290 nm. Therefore, in this paper, a fixed absorption wavelength of 290 nm is used to measure the absorbance of cotton textile wastewater filtered through a membrane.

[0070] Using a spectrophotometer at a wavelength of 290 nm, with pure water as a blank control, fifteen sets of cotton textile wastewater standard solutions were prepared with volume ratios of raw cotton textile wastewater to distilled water of 1:1, 1:2, 1:3...1:14, 1:15. The absorbance of each solution was measured, the results were recorded, and a standard curve for the cotton textile wastewater was plotted. The equation of the standard curve is: y=1.968x^0.532, and the correlation coefficient R2 is 0.969.

[0071] The effect of preparing carbon membranes by mixing coal coke and biochar on separation performance

[0072] As described in Experiment 1 above, six coal-coke membranes with biochar to coke ratios of 1:1, 1:2, 1:2.5, 1:3, 1:3.5, and 1:4 were prepared. A standard solution of cotton textile wastewater with an absorbance of A=1.038 at a wavelength of 290 nm was prepared, and an appropriate amount of the solution was repeatedly filtered through the coal-coke membranes using a membrane separation device. Each of the six membranes was filtered five times. The absorbance of the final filtered cotton textile wastewater was tested again, and the absorbance was recorded and the rejection rate was calculated to obtain the effect of different biochar-coke ratios on the separation performance.

[0073] As the content of coal char increases, the separation performance of the carbon membrane for the first filtration of cotton textile wastewater gradually decreases. When the ratio of biochar to coal char is 1:1, the retention rate reaches 94.12%. The separation performance is worst at 1:3. After that, the separation performance shows a linear recovery as the content of coal char increases, reaching the maximum value at 1:4, with a retention rate of 94.61%.

[0074] In biochar to coke ratios of 1:1, 1:2, and 1:2.5, the separation performance showed a linear relationship with the increase of the proportion of coke. The retention rate of 1:2.5 reached 98.17%. When the ratio was 1:3, the separation effect decreased slightly. After five filtrations, the retention rate of 1:4 reached 95.37%. However, the filtration speed of the carbon membrane made from biochar and coke was relatively slow. The following uses phenolic resin instead of coke to explore the filtration speed of the carbon membrane.

[0075] Effect of different ratios of biochar and phenolic resin mixed on separation performance

[0076] Based on Experiment 1, coal char was replaced with phenolic resin to prepare three phenolic resin mixed carbon membranes with ratios of 1:1, 1:2, and 1:3, respectively, and zinc nitrate as the dopant. The membranes were used to filter a standard solution of cotton textile wastewater at a wavelength of 290 nm and an absorbance of A=1.037 five times, and the absorbance of the filtrate was measured to obtain the effect of different biochar to phenolic resin ratios on the separation performance of cotton textile wastewater.

[0077] With increasing phenolic resin content, the separation performance increases linearly, reaching its maximum at a biochar to phenolic resin ratio of 1:3, with a rejection rate of 74.07%. However, since its separation rate is much higher than that of carbon membranes made from biochar and coal char, phenolic resin can be used to optimize coal char membranes to improve their separation rate.

[0078] Effect of biochar and coal char phenol resin mixture on separation performance

[0079] As described in Experiment 2 above, a mixture of phenolic resin and coal char was prepared by mixing the mixture of biochar and coal char. Five different ratios of biochar and coal char mixture were prepared: 1:1, 1:3, 1:4, 1:5, and 1:6. A cotton textile standard solution with a wavelength of 290 nm and absorbance A = 1.005 was filtered six times. The absorbance of the filtered cotton textile waste liquid was tested, and the rejection rate was calculated.

[0080] As the proportion of the coal-coke mixture increases, the membrane separation performance becomes better and the separation effect becomes more stable. The separation performance is best when the ratio of biochar to coal-coke mixture is 1:6, with a rejection rate of up to 97.81% and a fast filtration speed. The phenolic resin makes the carbon membrane more rigid and less prone to damage.

[0081] The effect of adding coal-coke mixture during secondary drying on the membrane separation performance of coal-coke.

[0082] As shown in Experiment 3 above, biochar and coal char were mixed in ratios of 1:1, 1:2, 1:3, 1:4, 1:5, and 1:6 to prepare coal char matrix carbon membrane precursors. After the first thermal curing and grinding into powder, the coal char was replaced with a 1:1 mixture of coal char phenolic resin. The other experimental conditions were the same as in Experiment 1, resulting in six mixed matrix carbon membranes with different ratios. A cotton textile standard solution with a wavelength of 290 nm and an absorbance A=1.087 was filtered five times. The absorbance of the filtered cotton textile waste liquid was tested, and the rejection rate was calculated.

[0083] In the first filtration, the separation performance was optimal when the ratio of biochar to coke was 1:2, with a retention rate of 91.62%. Subsequently, the separation performance deteriorated with the increase of coke content, reaching its lowest point at a ratio of 1:5, with a retention rate of only 2.85%.

[0084] When the coke was replaced with a coke mixture during secondary processing, the separation effect was more obvious when the ratio of biochar to coke was 1:1 and 1:2, with the 1:1 ratio showing the best separation effect, reaching a retention rate of 97.15%. At a ratio of 1:3, the retention rate was 64.49%. At ratios of 1:4, 1:5, and 1:6, the separation performance was poor, and the changes in separation performance were not significant. Overall, the separation effect was unstable.

[0085] in conclusion

[0086] This paper demonstrates the significant effect of using coal char to prepare carbon membranes for the purification of cotton spinning wastewater. This has practical significance for the treatment of industrial cotton spinning wastewater and can provide a reference for the field of membrane separation. The experimental conclusions are as follows:

[0087] Experiments using biochar and coke mixtures at different ratios to prepare membranes showed that the separation performance tended to increase with the increase of the proportion of coke, and the effect reached its highest at a ratio of 1:2.5, with a retention rate of 98.17%. The results show that in the mixed membrane prepared from biochar and coke, the separation effect is better with the increase of coke content, but the pore size of the membrane also becomes smaller and the filtration speed is slower with the increase of coke content.

[0088] 2. Membranes were prepared by mixing biochar and phenolic resin in different proportions to investigate whether coal char affects the separation rate. The separation performance did not change significantly with increasing phenolic resin content. The strongest separation performance was observed at a ratio of 1:2, with a rejection rate of 74.07%. However, the addition of phenolic resin significantly accelerated the separation speed of the biochar membrane.

[0089] 3. Membrane preparation by mixing biochar and coal char phenolic resin at a 1:1 ratio: Mixing phenolic resin as a binder with coal char at a 1:1 ratio can greatly improve the hardness of the prepared membrane and make it easier to burn when carbonized in a muffle furnace, thus improving the membrane preparation success rate and significantly accelerating the separation rate. As the proportion of the coal char phenolic resin mixture increases, the membrane separation performance also increases. The best effect is achieved at a ratio of 1:6, with a retention rate of 97.81%. Therefore, adding phenolic resin in both the first and second processing stages can have a beneficial effect on the coal char membrane.

[0090] 4. Using a mixture of biochar and coke to form a membrane, with the coke replaced only in the second processing stage as a 1:1 mixture of coke and phenolic resin: When the ratio of biochar to coke is 1:1, the separation effect is the best, with a rejection rate of 97.15%. As the ratio increases, the overall separation effect gradually decreases and becomes unstable. At a ratio of 1:6, the rejection rate is 21.17%, which seriously affects the membrane's separation effect on cotton textile wastewater. Therefore, it can be seen that replacing the added coke with a 1:1 mixture of coke and phenolic resin only in the second processing stage will affect the membrane's separation effect, and the more added, the worse the separation effect.

[0091] The above embodiments are only used to illustrate the present utility model and are not intended to limit the technical solutions described in the present utility model. Although the present utility model has been described in detail with reference to the above embodiments, the present utility model is not limited to the specific embodiments described above. Therefore, any modifications or substitutions to the present utility model, and all technical solutions and improvements that do not depart from the spirit and scope of the utility model, are covered within the scope of the claims of the present utility model.

Claims

1. A coal coke membrane, characterized in that, It includes a coal and coke base layer (1), on which a biochar layer (2) is attached, a dopant layer (3) is disposed on the biochar layer (2), and a thermosetting phenolic resin layer (4) is disposed on the dopant layer (3).

2. The coal coke membrane according to claim 1, characterized in that, The dopant layer (3) is made of non-metallic mineral materials.

3. The coal coke membrane according to claim 2, characterized in that, The non-metallic mineral materials include vermiculite and sepiolite.

4. The coal coke membrane according to claim 3, characterized in that, The thermosetting phenolic resin layer (4) is provided with a phenolic resin adhesive.

5. A coal coke membrane according to claim 4, characterized in that, The pore size of the coal and coke base layer (1) is distributed between 0.1 micrometers and 10 micrometers.

6. The coal coke membrane according to claim 5, characterized in that, The thickness of the coal and coke base layer (1) ranges from 0.1 mm to 2 mm.

7. A coal coke membrane according to claim 6, characterized in that, The coal and coke base layer (1) is in the shape of a flat plate, a tubular shape, or a hollow fiber shape.

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