Biochar catalytic material and catalytic membrane prepared by synergistic pyrolysis of coking sludge and soybean meal as well as preparation method and application of biochar catalytic material and catalytic membrane

Abstract

The invention belongs to the field of treatment of organic pollutants in environmental water, and particularly relates to a biochar catalytic material and a catalytic membrane obtained through synergistic pyrolysis of coked sludge and soybean meal as well as a preparation method and application of the biochar catalytic material and the catalytic membrane. Coking wastewater dry sludge is used as a raw material, after soybean meal is compounded, a mixture is pyrolyzed under the anaerobic condition, the ordered and porous-structure biochar catalytic material is obtained, the material can efficiently activate persulfate, and efficient degradation of organic pollutants is achieved; the biochar catalytic material is uniformly dispersed in a PVDF / PVP / DMF solution, the composite catalytic membrane is prepared by in-situ co-casting through a non-solvent induced phase inversion method, and experiments prove that the biochar catalytic material has good catalytic activity, hydrophilicity, mechanical strength and membrane flux. According to the invention, functional materialization and high-value utilization of the coking residual sludge are realized, a catalytic membrane material and a wastewater treatment device which can be stably applied for a long time are provided, and reduction of industrial hazardous wastes and treatment of refractory wastewater are assisted.

Description

Technical Field

[0001] This application belongs to the field of organic pollutant treatment in environmental water bodies, and more specifically, relates to a biochar catalytic material, catalytic membrane, and preparation method of the co-pyrolysis of coking sludge and soybean meal, as well as its application. In particular, it relates to a sludge-based biochar catalytic material and composite membrane material prepared by co-pyrolysis of coking sludge and soybean meal, and their application in the treatment of organic pollutant wastewater in advanced oxidation processes. Background Technology

[0002] With the rapid development of industries such as coking, fine chemicals, and petrochemicals, the discharge of coking wastewater has increased significantly. This type of wastewater mainly originates from processes such as coal dry distillation and coal gas purification, and contains large amounts of highly toxic organic pollutants such as phenols, cyanides, heterocyclic compounds, and polycyclic aromatic hydrocarbons. It is characterized by high concentration, high color, high toxicity, and poor biodegradability. The aromatic compounds in this wastewater are structurally stable and difficult to degrade by microorganisms, exhibiting strong persistence and bioaccumulation, posing a serious threat to the ecological environment and human health. Traditional biochemical or physicochemical treatment processes have limited efficiency in removing these recalcitrant organic pollutants, making it difficult to consistently meet effluent quality standards. Therefore, developing a highly efficient, stable, and long-term operable advanced oxidation system to achieve deep purification of recalcitrant organic wastewater such as coking wastewater has become a key research direction in the field of industrial wastewater treatment.

[0003] In the treatment of coking wastewater, a large amount of residual biochemical sludge forms high-iron dry sludge after thickening and dewatering using a plate press. This type of sludge is characterized by high iron content, complex organic matter, and high ash content. The iron mainly originates from three sources: First, during coking production, equipment and pipelines are exposed to corrosive gases such as H2S, HCN, and NH3 for extended periods, producing iron ion corrosion products that enter the wastewater system with the condensate. Second, the widespread use of iron-containing coagulants (such as polyferric sulfate and ferric chloride) and Fenton oxidation systems in coking wastewater treatment causes a large amount of iron to deposit in the sludge as hydroxides or oxides. Third, iron ions form complexes or co-precipitates with organic functional groups (carboxyl, hydroxyl, and amino groups) in the sludge, further enriching the iron after dewatering and thickening. This characteristic makes coking sludge a potential source of iron-based catalytic materials, but it also brings problems such as high treatment difficulty, high disposal costs, and high environmental risks.

[0004] Currently, landfilling and incineration remain the mainstream methods for disposing of coking sludge. However, these traditional methods not only occupy a large amount of land resources but also easily cause secondary pollution and heavy metal migration, making it difficult to achieve resource utilization. Pyrolysis of coking sludge into sludge-based biochar can effectively achieve sludge reduction, harmlessness, and high-value utilization.

[0005] Existing sludge biochar-based powder catalysts have significant limitations in engineering applications: the powders are prone to agglomeration in the aqueous phase, are lost with the effluent, and are difficult to recover, leading to loss of active components, increased risk of secondary pollution, and poor long-term stability. Furthermore, the powders exhibit low interfacial contact efficiency and insufficient exposure of active sites in continuous flow systems, hindering sustained electron transfer and reactive oxygen species generation. Therefore, immobilizing the catalytic function into a membrane format has become a feasible approach. Polyvinylidene fluoride (PVDF) is frequently used as a substrate due to its excellent chemical stability, mechanical strength, and film-forming processability, facilitating the integrated design of catalyst immobilization and reaction-separation. However, traditional PVDF membranes also suffer from problems such as poor hydrophilicity, simple pore structure, easy flux decay, and susceptibility to adsorption and fouling by organic matter. Furthermore, existing methods typically involve simple filtration to immobilize powdered catalysts within the PVDF membrane. While loading metal oxides or carbon materials can improve activity in the short term, this often results in uneven dispersion of active components and difficulty in precisely controlling the layer thickness. This can lead to increased mass transfer resistance, insufficient utilization of active sites, weak bonding strength, and susceptibility to active component shedding during fluid flushing, as well as short operating cycles. Consequently, it is difficult to maintain stable performance during continuous long-term operation in complex industrial wastewater treatment. Therefore, there is an urgent need to develop a novel composite catalytic membrane material that can both immobilize highly active catalytic sites and overcome the flux decay and fouling problems of PVDF membranes, achieving an effective balance between catalytic activity, structural stability, and continuous engineering applications. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this application is to provide a biochar catalytic material, catalytic membrane and preparation method of co-pyrolysis of coking sludge and soybean meal, and its application, aiming to solve the technical problems of poor catalytic degradation effect of existing sludge-based biochar in treating wastewater pollutants and poor long-term operational stability of the prepared catalytic material.

[0007] To achieve the above objectives, in a first aspect, this application provides a method for preparing a biochar catalytic material for the synergistic pyrolysis of coking sludge and soybean meal, comprising the following steps: Step a: After drying the coking sludge, mix it with soybean meal and grind it to obtain a sludge-soybean meal mixture; Step b: The sludge-soybean meal mixture obtained in step a is pyrolyzed under an inert atmosphere and cooled to room temperature to obtain biochar catalyst material.

[0008] Preferably, the mass ratio of the obtained dry sludge to soybean meal is 1:(0.5-2), and more preferably 1:(0.5-1.5).

[0009] Preferably, the sludge-soybean meal mixture described in step b is pyrolyzed at 600-900 °C for 1.5-2.5 h under a nitrogen atmosphere at a heating rate of 5-10 °C / min.

[0010] Secondly, a biochar catalytic material for the synergistic pyrolysis of coking sludge and soybean meal prepared by the aforementioned preparation method is provided.

[0011] Thirdly, a method for preparing a biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal is provided, comprising the following steps: Step S1: Dissolve polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) in N,N-dimethylformamide (DMF) solution and stir continuously to form a uniform casting solution. Then remove the air bubbles to obtain the support layer solution. Step S2: Disperse the biochar catalytic material as described in claim 5 with PVDF and PVP in a DMF solution, stir continuously, remove the air bubbles after stirring to obtain a biochar coating solution, which serves as the catalytic layer; Step S3: The PVDF support solution and the biochar coating solution are successively coated onto the nonwoven fabric to achieve in-situ co-casting. After co-casting, the membrane is immersed in pure water to complete phase separation, thereby obtaining a biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal.

[0012] Fourthly, a biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal prepared by the aforementioned method is provided.

[0013] Fifthly, the application of the biochar catalytic material for the synergistic pyrolysis of coking sludge and soybean meal, or the biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal, in the degradation of pollutants in wastewater is provided.

[0014] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: (1) The biochar catalytic material (SD-CSBC) prepared by the co-pyrolysis of coking sludge and soybean meal in this invention introduces a nitrogen-rich carbon framework structure through the co-pyrolysis of soybean meal, promoting the formation of Fe-NC active centers and significantly improving electron transfer efficiency and singlet oxygen generation capacity. Compared with biochar obtained from the pyrolysis of sludge alone, the obtained SD-CSBC... x -CSBC has a higher specific surface area, richer pore structure and more stable Fe valence state distribution, thus achieving efficient activation of PMS and rapid mineralization of recalcitrant pollutants such as phenol.

[0015] (2) The dopant soybean meal used in this invention is a widely available and inexpensive natural agricultural by-product. It is rich in nitrogen and organic matter, and can achieve self-doping in situ during pyrolysis without the need to add expensive chemical reagents or nitrogen sources, thereby significantly reducing the preparation cost.

[0016] (3) The degradation rate of phenol in the SD-CSBC / PMS system prepared in this invention remained at 81.76% after five cycles at 30 min.

[0017] (4) The biochar catalyst material for the synergistic pyrolysis of coking sludge and soybean meal prepared in this invention exhibits broad pH adaptability and excellent resistance to interference from coexisting substances. It can maintain high catalytic activity in acidic, neutral and alkaline water as well as in actual water environments; at the same time, the common anions, cations and humic acids in water have a significantly weak effect on its degradation efficiency, showing excellent potential for practical application.

[0018] (5) The biochar material and its catalytic membrane prepared by the present invention for the synergistic pyrolysis of coking sludge and soybean meal can achieve the integration of reaction and separation while maintaining high reactivity.

[0019] (6) The present invention uniformly disperses the prepared coking sludge soybean meal composite biochar catalytic material in PVDF / PVP / DMF solution, and in-situ co-casts the composite catalytic membrane material by non-solvent-induced phase transformation method. This invention effectively solves the technical problems of uneven dispersion and weak bonding of existing biochar powder materials on PVDF support membrane, resulting in poor catalytic activity and easy detachment and instability.

[0020] (7) The biochar catalytic material and its catalytic membrane prepared by the present invention for the synergistic pyrolysis of coking sludge and soybean meal have excellent hydrophilicity, mechanical strength and water flux, can operate stably for a long time, significantly reduce catalyst loss and metal ion leaching, and achieve efficient activation of PMS and continuous degradation of organic pollutants under continuous flow conditions. It has good potential for industrial scale-up. Attached Figure Description

[0021] Figure 1 The images show SEM images of coking sludge biochar CSBC (content (a)), biochar SD1-CSBC obtained by co-pyrolysis of coking sludge and soybean meal (content (b)), and soybean meal biochar SD (content (c)) from embodiments of the present invention.

[0022] Figure 2 The results are BET, Raman, hysteresis loop and XRD analysis results for SD1-CSBC.

[0023] Figure 3 For CSBC, SD x - Degradation efficiency of CSBC and SD for phenolic pollutants (content(a)), TOC degradation rate (content(b)), cycling experiment (content(c)) and anion effect (content(d)).

[0024] Figure 4 Comparison of phenol degradation rates of biochar catalytic materials prepared from different nitrogen-rich biomass pyrolysis.

[0025] Figure 5 Comparison of phenol catalytic degradation rates for biochar catalysts prepared by combining different types of sludge with soybean meal.

[0026] Figure 6 Three-dimensional fluorescence spectra of SD1-CSBC for the degradation of coking wastewater biochemical effluent (contents (a) and (e)), eutrophic landscape lake water (contents (b) and (f)), and natural lake (contents (c) and (g)).

[0027] Figure 7 The images show the AFM diagrams of the SD1-CSBC@PVDF membrane and the PVDF membrane without a catalyst layer in the embodiments of the present invention.

[0028] Figure 8 This is a schematic diagram of the continuous flow device using the biochar catalytic membrane material employed in Application Example 5.

[0029] Figure 9 This is a diagram showing the continuous flow degradation effect of the biochar catalytic membrane material in Example 5.

[0030] Figure 10 Schematic diagram of a dead-end flow reactor for biochar catalytic membrane material (content (a)) and schematic diagram of a tangential flow reactor for biochar catalytic membrane material (content (b)).

[0031] Figure 11 This image shows the pollutant degradation effect of a biochar / PVDF composite membrane constructed by vacuum filtration. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0033] The present invention provides a method for preparing a biochar catalytic material for the synergistic pyrolysis of coking sludge and soybean meal, comprising the following steps: Step a: After drying the coking sludge, mix it with soybean meal and grind it to obtain a sludge-soybean meal mixture; Step b: The sludge-soybean meal mixture obtained in step a is pyrolyzed under an inert atmosphere and cooled to room temperature to obtain biochar catalyst material.

[0034] In some embodiments, the dried sludge in step a is obtained by the following method: drying coking sludge in an oven at 60-105 °C for 4-12 h to obtain the dried sludge; in step a, the dried sludge is mixed with soybean meal and then ground, the particle size is not required, and the lumps are broken up. The mass ratio of the obtained dried sludge to soybean meal is 1:(0.5-2), more preferably 1:(0.5-1.5).

[0035] In some embodiments, the sludge-soybean meal mixture described in step b is pyrolyzed at a constant heating rate of 5-10 °C / min at 600-900 °C under a nitrogen atmosphere for 1.5-2.5 h.

[0036] In some embodiments, after pyrolysis in step b, the sample is cooled to room temperature, ground, passed through a 200-mesh sieve, and the sieve-passing material is washed 2-4 times each with water and anhydrous ethanol.

[0037] The biochar catalytic material prepared by this invention for the synergistic pyrolysis of coking sludge and soybean meal, as analyzed, has an Fe content of 28.1-61.3 wt% and a specific surface area of ​​48.4-217.6 m². 2 / g, with an average pore size of 9-18.6 nm; saturation magnetization of 0.03-41.84 emu / g, and defect degree ID / IG value of 0.87-1.21.

[0038] This invention also provides a method for preparing a biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal, comprising the following steps: Step S1: Dissolve polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) in N,N-dimethylformamide (DMF) solution and stir continuously to form a uniform casting solution. Then remove the air bubbles to obtain the support layer solution. Step S2: Disperse the biochar catalyst material with PVDF and PVP in DMF solution and stir continuously. After stirring, remove the air bubbles to obtain a biochar coating solution, which serves as the catalyst layer. Step S3: The PVDF support solution and the biochar coating solution are successively coated onto the nonwoven fabric (the PVDF support solution is coated first, and the biochar coating solution is coated on top of it) to achieve in-situ co-casting. After co-casting, the fabric is immersed in pure water to complete phase separation, and a biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal is obtained.

[0039] In some embodiments, the mass concentration of PVDF in the PVDF-supported solution in step S1 ranges from 15-25 wt%; the mass concentration of PVP ranges from 1-5 wt%. In step S2, the biochar coating solution contains biochar catalyst at a concentration ranging from 1 to 5 wt%; PVDF at a concentration of 7 to 9 wt%; and PVP at a concentration of 1 to 3 wt%. In some embodiments, mechanical stirring is used in steps S1 and S2, with stirring parameters of 150-300 rpm and a duration of 8-12 hours. The removal of air bubbles specifically involves: placing the container in an oven at 30-50 ℃ for 3-6 hours, or removing the air bubbles by ultrasound at a frequency of 20-40 kHz for 20-30 min. After co-casting in step S3, the mixture is immersed in pure water for 6-12 hours to complete phase separation.

[0040] The biochar catalytic membrane prepared by the present invention for the synergistic pyrolysis of coking sludge and soybean meal has the following characteristics: the surface arithmetic mean roughness (Ra) is 23.8-110.8 nm, the root mean square roughness (Rq) is 30.1-141.7 nm, the maximum height (Rmax) is 234.9-1067 nm, and the water contact angle of the catalytic membrane is 60.1°-69.3°.

[0041] The biochar catalytic material or biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal provided by this invention can be used to degrade pollutants in wastewater. In application, the biochar catalytic material of this invention is mixed with the wastewater to be degraded, or the wastewater to be degraded is passed through the biochar catalytic membrane of this invention for pollutant degradation, and the wastewater to be degraded also contains persulfate.

[0042] The biochar catalytic material or catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal of this invention can treat wastewater including, but not limited to, industrial wastewater containing recalcitrant organic pollutants, especially biochemical effluent from coking wastewater, petrochemical wastewater, phenolic resin wastewater, combined wastewater from coal chemical and coking industries, and effluent from reclaimed water reuse systems containing aromatic or polar recalcitrant organic matter. The biochar catalytic material and catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal provided by this invention achieve highly efficient degradation of organic pollutant wastewater through the synergistic effect of membrane separation and advanced oxidation processes.

[0043] In some application examples, the biochar catalyst material for the synergistic pyrolysis of coking sludge and soybean meal prepared according to this invention, along with persulfate, is added to wastewater containing organic pollutants to degrade the pollutants. The concentration of persulfate is 0.3-0.5 g / L; the biochar dosage is 0.3-1.0 g / L; the degradation time is 0.5-2 h; and the stirring speed is 300-600 rpm. The pollutants are degraded mainly through singlet oxygen and direct electron transfer pathways, achieving organic matter mineralization.

[0044] In other application embodiments, biochar catalysts obtained by synergistic pyrolysis of coking sludge and soybean meal are used for the deep treatment of organic matter in wastewater. The wastewater is low-concentration organic wastewater containing recalcitrant aromatic compounds, or biochemical effluent from high-concentration organic industrial wastewater, wherein the chemical oxygen demand (COD) is not higher than 400 mg / L, the total organic carbon (TOC) is not higher than 250 mg / L, and the influent suspended solids (SS) is not higher than 80 mg / L.

[0045] In some application embodiments, the biochar material and its catalytic membrane obtained by co-pyrolyzing coking sludge and soybean meal prepared according to this invention are used for advanced wastewater treatment. The biochar catalytic material and catalytic membrane of this invention combine separation and catalysis functions, enabling simultaneous effluent clarification and removal of organic pollutants. The wastewater is industrial wastewater containing recalcitrant organic pollutants, especially biochemical effluent from coking wastewater, petrochemical wastewater, and phenolic resin wastewater. The biochar catalytic membrane of this invention can operate stably in continuous flow reaction mode and can be operated using dead-end filtration or cross-flow filtration devices. The membrane module maintains a stable system flow rate (40-80 L / m³) through a peristaltic pump or constant pressure pump. 2 •h). During operation, a stable hydration layer forms on the membrane surface, which can effectively prevent irreversible fouling of the membrane surface by intermediate products or suspended particles, thereby achieving long-term synergistic operation of catalysis and separation.

[0046] In some embodiments, when the membrane flux of the biochar catalytic membrane of the present invention drops below 70% of its initial value, a backwashing operation is required. The backwashing method is to backwash from the membrane effluent side with deionized water or diluted PMS solution (1–2 mmol / L) for 10–15 min. It is recommended to perform a physical backwash + chemical flush (e.g., 0.1 mol / L NaOH or H2O2 solution, at a temperature of 25–35 °C) every 15–20 days. When the membrane flux or catalytic activity remains below 60% of its initial performance for an extended period, it is recommended to replace the membrane module. The service life of a single membrane is approximately 3–6 months, depending on the wastewater load and operating conditions.

[0047] The primary technical problem addressed by this invention is to develop a method for rapidly degrading pollutants using highly active biochar activated from PMS (Polymerase Regulator) using co-fired sludge as raw material. This method involves the co-pyrolysis of coking sludge and soybean meal to prepare biochar. Soybean meal, as a high-protein byproduct, is rich in amino acids, polypeptides, and polysaccharides, and its pyrolysis process allows for effective nitrogen doping and structural expansion. After co-pyrolysis with coking sludge, the resulting composite biochar not only forms a well-developed porous structure and a high specific surface area, but also introduces active functional groups such as -N and -O into the carbon framework, promoting PMS activation and singlet oxygen (SNO). 1The generation of O2 and the enhancement of biochar conductivity promote direct electron transfer, thereby significantly enhancing the oxidative degradation capacity of organic pollutants. The second technical problem this invention aims to solve is to provide a composite method of sludge-based biochar and PVDF membrane, incorporating an advanced oxidation process within the membrane to construct a catalytic membrane reactor that combines high catalytic activity, long-term operational stability, and good engineering applicability, achieving continuous and efficient degradation of pollutants. This provides a new technical approach for the deep treatment of industrial wastewater and the resource utilization of coking sludge.

[0048] This invention provides a method for preparing biochar catalytic materials and catalytic membranes by co-pyrolysis of residual sludge from a coking wastewater plant and soybean meal, as well as an in-situ co-casting method for biochar@PVDF bilayer composite membranes and their application in water treatment. Specifically: (1) Using dry sludge from a plate and frame filter press in a coking wastewater plant as raw material, the mixture is pyrolyzed under anaerobic conditions by optimizing the amount of soybean meal added (0-67.0 wt%) to obtain a biochar catalytic material (SDx-CSBC) with an ordered and porous structure. This material can efficiently activate persulfate, achieving efficient degradation of organic pollutants; (2) SDx-CSBC is uniformly dispersed in an optimized PVDF / PVP / DMF solution, and an SDx-CSBC / @PVDF bilayer composite catalytic membrane material can be prepared by in-situ co-casting using non-solvent-induced phase inversion (NIPS), exhibiting good hydrophilicity, mechanical strength, and membrane flux; (3) A water treatment application device and method for this composite catalytic membrane are proposed, achieving long-term, efficient, and stable degradation (≥60 days) of target organic pollutants under continuous flow operation mode. Based on the concept of "treating waste with waste", this invention has successfully realized the functionalization and high-value utilization of coking waste sludge, and provides a catalytic membrane material and wastewater treatment device that can be used stably for a long time, which helps to reduce industrial hazardous waste and treat recalcitrant wastewater.

[0049] The embodiments of the present invention are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The process parameters in the following embodiments that do not specify specific conditions are generally in accordance with conventional conditions.

[0050] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0051] The process parameters in the following examples, unless otherwise specified, are generally performed under conventional conditions.

[0052] The embodiments of this application are described below with reference to the accompanying drawings.

[0053] Example 1 First, coking sludge from the plate press of a coking wastewater treatment plant was dried in an oven at 105℃ for 4 hours to obtain dry sludge. The dry sludge was then physically mixed with soybean meal (a solid byproduct of soybean deoiling, derived from grain and oil processing and feed industries) at specific mass ratios (1:0.5, 1:1, 1:1.5, 1:2) and ground. The sludge-soybean meal mixture was then pyrolyzed in a tube furnace at 700℃ under a nitrogen atmosphere for 2 hours at a constant heating rate of 10℃ / min. Afterward, the sample was allowed to cool naturally to room temperature and washed three times each with water and anhydrous ethanol to obtain cleaned biochar catalyst material. The cleaned biochar catalyst material was then dried in an oven at 60℃ for 6 hours to obtain sludge-based biochar catalyst material (SD-CSBC).

[0054] Depending on the ratio of sludge to soybean meal, this catalytic material is named SD. x -CSBC (x=0.5, 1, 1.5, 2), the sludge-based biochar catalysts prepared by mixing dry sludge and soybean meal at mass ratios of 1:0.5, 1:1, 1:1.5, and 1:2 are SD 0.5 -CSBC, SD1-CSBC, SD 1.5 -CSBC and SD2-CSBC. Biochar material prepared from coking sludge without soybean meal doping is named CSBC, and biochar material prepared from soybean meal only under the same conditions is named SD.

[0055] Figure 1 SEM images of the coking sludge biochar CSBC (content (a)), the biochar SD1-CSBC obtained from the co-pyrolysis of coking sludge and soybean meal (content (b)), and the soybean meal biochar SD (content (c)) prepared in this embodiment are shown. SD1-CSBC exhibits a highly rough and hierarchical surface morphology, with fine particles and blocky structures intertwined to form continuous multi-scale aggregates. The surface micro-nano-scale protrusions are more dense than those of CSBC and are highly similar to those of SDBC, which has a distinctly granular and cauliflower-like protrusion structure, showing strong structural reconstruction and heterogeneous fusion characteristics.

[0056] Figure 2 The results of BET (content (a)), Raman (content (b)), hysteresis loop (content (c)), and XRD (content (d)) analyses of the SD1-CSBC prepared in this embodiment are shown. The analysis revealed that doping with soybean meal significantly increases the specific surface area and defect level of the material, and Fe... xCharacteristic peaks for N (e.g., Fe3N) and Fe were observed and enhanced. VSM testing results showed that the biochar material exhibited significant magnetic response behavior, proving the presence of an iron oxide phase that imparts magnetism to the material, thus giving it good magnetic separation potential. Further ICP analysis revealed that the biochar catalytic material prepared in this embodiment contained 28.1-61.3 wt% Fe and had a specific surface area of ​​48.4-217.6 m². 2 / g, with an average pore size of 9-18.6 nm; saturation magnetization of 0.03-41.84 emu / g, and defect degree ID / IG value of 0.87-1.21.

[0057] Polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) were dissolved in N,N-dimethylformamide (DMF) solution, wherein the mass fraction of PVDF was 20 wt% and the mass fraction of PVP was 3 wt%. The mixture was mechanically stirred at 200 rpm for 10 hours to form a uniform casting solution. The solution was then placed in an oven at 40°C for 4 hours to remove air bubbles, which served as the PVDF support layer solution.

[0058] 2.5 wt% SD1-CSBC, 8 wt% PVDF, and 2 wt% PVP were dissolved in DMF solution and stirred mechanically at 200 rpm for 10 hours to obtain a biochar coating solution. The solution was then placed in an oven at 40 ℃ for 4 hours to remove air bubbles, thus serving as a catalyst layer.

[0059] The biochar coating solution and PVDF support solution were coated onto a nonwoven fabric using a doctor blade (the PVDF support solution was coated first, followed by the biochar coating solution), achieving in-situ co-casting. The co-cast solution was then immersed in pure water for 12 hours to complete phase separation, resulting in a highly efficient biochar catalytic membrane.

[0060] Comparative Example 1 The rest is the same as in Example 1, except that the soybean meal is replaced with the same mass of crab shell powder, and the mass ratio of dry sludge to crab shell powder is 1:1.

[0061] Comparative Example 2 The rest is the same as in Example 1, except that soybean meal is replaced with the same mass of Chlorella, and the mass ratio of dry sludge to Chlorella is 1:1.

[0062] Comparative Example 3 The rest is the same as in Example 1, except that soybean meal is replaced with the same mass of distiller's grains, and the mass ratio of dry sludge to distiller's grains is 1:1.

[0063] Comparative Example 4 The rest is the same as in Example 1, except that the coking sludge is replaced with the same mass of municipal sludge, and the mass ratio of dry sludge to soybean meal is 1:1.

[0064] In the following application examples: the concentration of phenol was determined by high-performance liquid chromatography (HPLC) with a mobile phase of 1‰ (v / v) acetic acid and acetonitrile (v / v = 35% : 65%) at a flow rate of 0.8 mL / min. The degree of mineralization of organic matter was evaluated using total organic carbon (TOC), which was determined using a total organic carbon / nitrogen analyzer. The chemical oxygen demand (COD) in coking wastewater was... Cr The changes were tested and analyzed in accordance with the national industry standard "Water Quality - Determination of Chemical Oxygen Demand - Dichromate Method" (HJ828-2017).

[0065] Application Example 1 0.025 g of SD1-CSBC catalyst was added to 50 mL of 50 mg / L phenol solution. A control group was set up using the same dosage of 0.5 g / L CSBC and SD1 prepared in Example 1. 0.5 -CSBC, SD 1.5 The CSBC, SD2-CSBC, and SD systems were pre-adsorbed for 30 min under magnetic stirring. After pre-adsorption, 0.5 mL of 50 mg / L PMS (potassium peroxymonosulfate) solution was added, and the reaction was allowed to proceed for 60 min. Samples were taken at intervals along the reaction path, filtered through a 0.22 μm filter membrane, and 50 μL of methanol was added to terminate the reaction. The resulting samples were analyzed using high-performance liquid chromatography (HPLC) to observe changes in phenol concentration. Simultaneously, 4 mL of the post-reaction sample was analyzed using an ICP-OES instrument to determine the leaching concentration of iron in the material.

[0066]

[0067] In the formula, η represents the removal rate. When calculating the phenol removal rate, C0 is the initial phenol concentration in the system; C is the phenol concentration in the system during the degradation process from 0 to 60 min. Figure 3 As shown in sections (a) and (b), the wastewater treated with SD1-CSBC catalytic material exhibited a pollutant degradation efficiency exceeding 99% and a TOC removal rate of 72%, significantly higher than the control group. The Fe leaching concentration was below 1.5 mg / L, meeting the Fe≤3 mg / L standard and complying with the Class III discharge standard of the Integrated Wastewater Discharge Standard GB 8978-1996. The degradation efficiency, from best to worst, was SD1-CSBC, SD... 0.5 -CSBC, SD 1.5-CSBC, SD2-CSBC, CSBC, SD, and a single PMS system. Moreover, the degradation effect data shows that the synergistic pyrolysis of coking sludge CSBC and soybean meal SD did achieve a significant synergistic catalytic effect compared to using either one as a catalyst alone. Compared with a single PMS system, it clearly synergistically promoted the activation of PMS and jointly improved the catalytic oxidation degradation effect of pollutants.

[0068] Crab shell powder mainly comes from by-products of the aquatic product processing industry, especially the waste such as crab shells and legs left after processing crabs (such as swimming crabs and mitten crabs). Chlorella is a freshwater single-celled green algae widely distributed in natural water bodies such as lakes and ponds. Currently, commercially available products mainly come from large-scale artificial cultivation, raised in strictly controlled open ponds or closed photobioreactors to ensure purity, yield, and food safety. Distillers' grains are a major by-product of the brewing industry (baijiu, beer, rice wine, etc.). Specifically, it is the solid residue remaining after brewing raw materials (such as sorghum, rice, wheat, grapes, etc.) have undergone fermentation, distillation, or pressing to extract alcohol. The crab shell powder, chlorella, and distillers' grains used in the comparative examples of this invention were all commercially available.

[0069] In the same experiment, the sludge biochar catalyst materials prepared in Comparative Examples 1 to 3 were also subjected to the same experiments and tests as described above. The experimental results are shown in the figure. Figure 4 It can be seen that, despite being nitrogen-rich biomass, the catalytic material obtained from the combined pyrolysis of crab shell powder, distiller's grains, and Chlorella with coking sludge biochar exhibits significantly inferior performance compared to the same weight of soybean meal. This may be due to differences in nitrogen occurrence forms, pyrolysis evolution behavior, and interfacial synergistic capabilities. Soybean meal is primarily composed of protein, with nitrogen mainly existing in amino and amide forms. During pyrolysis, it is more readily converted into electroactive nitrogen species such as pyridine N and graphitic N, and effectively coordinates with Fe species in coking sludge, promoting the construction of Fe–N active centers. In contrast, the nitrogen in crab shell powder is mostly derived from chitin, exhibiting strong thermal stability and accompanied by a large amount of inorganic components such as CaCO3. Distiller's grains and Chlorella contain a high proportion of ash, lipids, or amorphous components. These factors may be unfavorable to the efficient conversion of active nitrogen species and the formation of Fe–N synergistic structures, thereby weakening the built-in electric field and interfacial electron transfer capabilities, ultimately leading to a significant decline in catalytic performance.

[0070] Based on the above comparison results, it can be inferred that the high iron content in coking sludge may lead to the formation of Fe-OC and other structural active centers during the combined pyrolysis with soybean meal, giving it potential activation capabilities in the persulfate (PMS) system. However, biochar prepared solely from coking sludge as a raw material exhibits poor phenol degradation performance as a catalyst. This may be due to its dense structure, insufficient pore development, and limited specific surface area. It may also be primarily due to the high inorganic mineral content and low organic matter content in coking sludge, which easily leads to carbon skeleton collapse and mineral sintering during pyrolysis, resulting in limited exposure of surface reaction sites and impaired electron transport pathways, making it difficult to fully activate the iron active centers to participate in the efficient activation reaction of PMS. Biochar prepared solely from soybean meal as a raw material also shows poor phenol degradation performance, possibly due to the lack of efficient electron activation centers and a limited reaction interface structure. Furthermore, biochar derived from soybean meal is typically predominantly amorphous carbon with low graphitization and electrical conductivity. This embodiment significantly improves catalytic performance by regulating the carbon structure and electronic environment through the synergistic pyrolysis of soybean meal, a composite exogenous carbon- and nitrogen-rich organic compound, thereby achieving green recycling through "waste treatment of waste." Furthermore, a comparison of biochar catalytic materials obtained with different soybean meal doping amounts shows that the doping amount of soybean meal in the combined pyrolysis of soybean meal and coking sludge should not be too high or too low; the optimal ratio is 1:(0.5-1.5), and the best ratio is 1:1.

[0071] Comparative Example 4 replaced coking sludge with municipal sludge, and the prepared municipal sludge biochar catalyst was subjected to the same experiments and tests as described above. The experimental results are shown in [Figure 4]. Figure 5 It can be seen that the catalytic degradation ability of municipal sludge-soybean meal biochar for phenol is somewhat worse than that of the coking sludge-soybean meal biochar catalytic material in Example 1. This indicates that in the embodiments of the present invention, the coking sludge and soybean meal are combined to prepare biochar catalytic materials. The coking sludge and soybean meal work synergistically and are indispensable. The prepared catalytic material has excellent pollutant catalytic degradation effect.

[0072] Furthermore, after completing a 60-minute degradation reaction, the biochar material was recovered by centrifugation, washed several times with deionized water to remove surface residues, and then dried in an oven at 40-60℃. The recovered material was then re-immersed in a freshly prepared contaminant solution of equal concentration, and a new round of degradation experiments was initiated under the same conditions. This cycle was repeated a predetermined number of times (3-5 times). By comparing the contaminant removal efficiency and reaction kinetic constants of each cycle, the loss of active components, structural stability, and performance degradation of the material were systematically evaluated. The results showed that SD 1-CSBC exhibits good recyclability; after four cycles, the degradation rate constant decreases to 0.061, but it still achieves 100% removal within 60 minutes. After five cycles, the degradation rate of phenol remains at 81.76% after 30 minutes. Figure 3 As shown in content (c).

[0073] Application Example 2 Different concentrations (2, 5, 10, 50 mM) of anions and cations (CO3-) were added to 50 mL of 50 mg / L phenol solution. 2- NO3 - Cl - SO4 2- HCO3 - Na + K + Mg 2+ Ca 2+ Humic acid of different concentrations (2, 5, 10, 50 mg / L) was used. The concentration of SD1-CSBC material was set at 0.5 g / L and the concentration of PMS was set at 0.5 g / L. The mixture was placed on a magnetic stirrer for reaction, and the concentration of phenol was tested after 60 min using high performance liquid chromatography.

[0074]

[0075] In the formula, η represents the removal rate. When calculating the phenol removal rate, C0 is the initial phenol concentration in the system; C is the phenol concentration in the system after treatment with SD1-CSBC biochar material. For example... Figure 3 As shown in content (d), even under interference from 50 mM anions, cations, or 50 mg / L humic acid, the removal rate of phenol remained above 80%, demonstrating extremely strong anti-interference ability.

[0076] Application Example 3 100 mL of effluent from the biochemical treatment tank of a coking wastewater treatment plant was placed in a 250 mL beaker. The properties of the effluent from the biochemical treatment tank are shown in Table 1. The concentration of SD1-CSBC biochar material was set at 2 g / L, and the PMS dosage was 4 g / L. The reaction was carried out on a magnetic stirrer. After 3 hours of reaction, a sample was taken, filtered through a 0.45 μm filter membrane, and then added to a COD digestion tube. After adding digestion reagent and reacting, the absorbance of the sample was detected using a UV fluorescence spectrometer with λ set to 540 nm. In addition, 5 mL of the sample was diluted to a certain extent and the three-dimensional fluorescence was measured.

[0077] Table 1. Various indicators of biochemical effluent from a coking wastewater plant in Central China

[0078] Given the complex composition of coking wastewater, the following analysis will focus on two key indicators: TOC and COD.

[0079]

[0080] In the formula, η is the removal rate. When calculating the TOC or COD removal rate, C0 is the initial TOC or COD concentration of the system; C is the TOC or COD concentration of the system after 2 hours of catalyst treatment. After treatment, the COD removal efficiency reached 71%, and the COD concentration of the treated wastewater was 83 mg / L. The TOC removal efficiency reached 23%, and the TOC concentration of the treated wastewater was 106.4 mg / L. Simultaneously, the decolorization effect was significant, with the color decreasing by 50 times. The COD index is lower than the requirement of no more than 200 mg / L stipulated in the secondary standard of the "Integrated Wastewater Discharge Standard" (GB8978-1996).

[0081] like Figure 6 As shown in the three-dimensional fluorescence results, the fluorescence characteristic peaks were significantly reduced after treatment with SD1-CSBC biochar material. This indicates that SD1-CSBC biochar material can efficiently degrade or adsorb dissolved organic matter in water, significantly reducing the organic load and pollution level of the water sample.

[0082] Application Example 4 A method for preparing a PVDF substrate membrane includes dissolving 20 wt% polyvinylidene fluoride (PVDF) and 3 wt% polyvinylpyrrolidone (PVP) in an N,N-dimethylformamide (DMF) solution, and mechanically stirring at 200 rpm for 10 hours to form a homogeneous casting solution. After placing the solution in an oven at 40°C for 4 hours, the PVDF supporting solution is coated onto a nonwoven fabric using a doctor blade. Phase separation is completed after exposing the solution to air and immersing it in pure water for 12 hours. A catalyst-free PVDF membrane material is obtained.

[0083] The surface roughness of the biochar high-efficiency catalytic membrane material and the PVDF membrane material prepared in Example 1 were tested, and the test results are as follows: Figure 7 As shown, with the addition of the biochar coating solution from Example 1, the surface roughness increases, the effective filtration area becomes larger, and the permeate flux increases. Simultaneously, with the addition of the biochar coating solution, the contact angle decreases, and the hydrophilicity of the membrane is improved. Tests show that the surface arithmetic mean roughness (Ra) of the biochar catalytic membrane prepared in Example 1 is 23.8-110.8 nm, the root mean square roughness (Rq) is 30.1-141.7 nm, the maximum height (Rmax) is 234.9-1067 nm, and the water contact angle of the catalytic membrane is 60.1°-69.3°.

[0084] Application Example 5 Utilize Figure 8 The membrane reactor uses a biochar-based high-efficiency catalytic membrane material prepared from SD1-CSBC biochar material (Example 1) to activate PMS for the degradation of phenol-simulated wastewater: First, prepare 5 mg / L phenol-simulated wastewater, add 0.3 g / L PMS, and stir evenly; second, seal the biochar-based high-efficiency catalytic membrane material in the assembled membrane reactor; third, allow the PMS-containing phenol-simulated wastewater to flow evenly through the membrane reactor at a flux of 13 L / m³. 2 • The system was run continuously for 64 days. Samples were taken daily after membrane permeation. After passing through a 0.22 μm filter, 50 μL of methanol was added to terminate the reaction, and the phenol concentration was measured using high-performance liquid chromatography (HPLC). 100 μL of sample was added to PMS reagent, allowed to stand for 30 min, and the PMS concentration was measured using UV spectrophotometry. 40 mL of sample was taken, and the TOC concentration was determined using a total organic carbon / nitrogen analyzer. 3 mL of sample was taken, and the Fe leaching concentration in the material was measured using ICP-OES. During continuous operation, the system was artificially interfered with (Table 2), for example, by increasing the pump speed to achieve a membrane permeate flux of 29 L / m³. 2 •h, increase the phenol concentration to 15 mg / L, and introduce 1000 mg / L Cl into the phenol solution. - Adjust the pH of the phenol solution to be alkaline or acidic. The results are as follows: Figure 9 As shown, after 64 days of continuous operation, the phenol removal efficiency remained above 80%, indicating that the biochar high-efficiency catalytic membrane material can operate stably for a long time, significantly reducing catalyst loss and metal ion leaching, and achieving efficient activation of PMS and continuous degradation of organic pollutants under continuous flow conditions.

[0085] Table 2 Parameters of Biochar High-Efficiency Catalytic Membrane Material in Continuous Flow Operation

[0086] Application Example 6 use Figure 10The apparatus shown in section (a) continuously introduces biochemical effluent (pH=7.73, TOC concentration 101.2 mg / L) from a coking wastewater treatment plant into an equalization tank. Simultaneously, a suitable concentration of persulfate solution is pumped in. After thorough mixing in the equalization tank, the effluent enters a dead-end filtration catalytic membrane reactor. In the dead-end filtration catalytic membrane reactor, a flat-plate catalytic membrane (the biochar high-efficiency catalytic membrane prepared in Example 1) is secured to the middle of the membrane tank via flanges and pressure-resistant sealing rings, forming a pressure-bearing cavity. After being pressurized by a feed pump, the wastewater flows from the left side of the reactor to the membrane surface, forcibly penetrating the catalytic membrane layer under pressure. During this process, pollutants come into contact with and degrade at the catalytic sites, and the purified permeate is continuously discharged from the right end. This type of reactor typically does not have a return pipeline; all influent is forcibly filtered. During operation, transmembrane pressure, permeate flux, and effluent quality (such as TOC and characteristic pollutant concentrations) are monitored in real time. When membrane fouling causes the flux to drop to 50-70% of the initial value, start cleaning: first backwash with low-pressure reverse osmosis solution (pulse backwash for 30-60 seconds every 2-4 hours). If the effect is not good, use chemical circulation cleaning (such as 0.1M NaOH or H2O2 solution circulation for 30 minutes). Finally, restore membrane performance with clean water.

[0087] Results analysis: The initial membrane flux was 22 L / (m²). 2 After 4 hours of continuous operation, the membrane flux decreased to 15 L / (m²). 2 •h) A backwash is required, during which TOC is checked every hour until it drops below 45 mg / L.

[0088] Application Example 7 use Figure 10 The apparatus shown in content (b) continuously introduces biochemical effluent (pH=8.02, TOC concentration of 97.6 mg / L) from a coking wastewater treatment plant into the equalization tank, and simultaneously pumps in an appropriate concentration of persulfate solution. After thorough mixing in the equalization tank, the solution enters the tangential flow filtration catalytic membrane reactor.

[0089] In a tangential flow filtration membrane reactor employing a PVDF catalytic membrane, a flat-plate PVDF catalytic membrane (the biochar high-efficiency catalytic membrane prepared in Example 1) is precisely fixed within the membrane tank module using specialized clamps and corrosion-resistant sealing gaskets, forming a pressure-bearing, sealed cavity. A high-pressure feed pump pumps pretreated coking wastewater effluent from the biochemical tank into the membrane tank inlet at a specific flow rate. The wastewater flows parallel to the membrane surface at high speed, forming a tangential flow. During this process, organic matter in the wastewater comes into full contact with the nanoscale catalyst uniformly distributed within the PVDF membrane pores, undergoing catalytic degradation. Simultaneously, the fluid shear force continuously washes the membrane surface, preventing pollutant deposition. Part of the wastewater vertically penetrates the catalytic membrane under pressure, becoming permeate. The remaining wastewater is retained and mixed with the newly added influent through an external return pipeline before being returned to the system for recycling. This return setting can be precisely controlled by a regulating valve to achieve a return ratio (typically 150%-300%). During operation, key parameters such as transmembrane pressure, permeate flux, influent and effluent TOC / phenol concentrations, and pH values ​​are monitored in real time. The final effluent TOC consistently reached the standard of less than 30 mg / L.

[0090] The core advantages of this system are: (1) Through the synergistic effect of tangential flow design and in-situ catalyst loading, deep oxidation of pollutants and effective control of membrane fouling are achieved simultaneously; (2) The reflux system significantly improves mass transfer efficiency and reactant residence time, greatly increasing the removal rate of recalcitrant organic matter; (3) The modular structure combines the ease of maintenance of flat sheet membranes with the high efficiency of catalytic reaction, significantly delaying the formation of filter cake layer, maintaining long-term stable flux, reducing cleaning frequency and intensity, and is not afraid of easily fouled systems.

[0091] Comparative Example 5 The biochar catalyst SD1-CSBC prepared in Example 1 was deposited in situ onto the surface of a commercially available PVDF membrane via vacuum filtration to construct a biochar / PVDF composite membrane. Testing was conducted using the membrane device and first-stage conditions of Application Example 5. Results showed that after 20 days of continuous operation, the removal efficiency of phenol and TOC began to decline rapidly, stability decreased significantly, and the leaching of metal ions increased. Figure 11 As shown, this illustrates that the preparation process in this embodiment of the invention, which involves uniformly dispersing the prepared biochar catalytic material in a PVDF / PVP / DMF solution and then further preparing a composite catalytic membrane by in-situ co-casting using a solvent-inducible phase transformation method, can significantly improve the overall performance of the membrane material, including its mechanical strength and catalytic activity.

[0092] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a biochar catalytic material for the synergistic pyrolysis of coking sludge and soybean meal, characterized in that, Includes the following steps: Step a: After drying the coking sludge, mix it with soybean meal and grind it to obtain a sludge-soybean meal mixture; Step b: The sludge-soybean meal mixture obtained in step a is pyrolyzed under an inert atmosphere and cooled to room temperature to obtain biochar catalyst material.

2. The preparation method according to claim 1, characterized in that, The dried sludge described in step a is obtained by drying coking sludge in an oven at 60-105 °C for 4-12 h; and / or, The mass ratio of the resulting dry sludge to soybean meal is 1:(0.5-2), preferably 1:(0.5-1.5).

3. The preparation method according to claim 1, characterized in that, The sludge-soybean meal mixture described in step b is pyrolyzed at a heating rate of 5-10℃ / min at 600-900℃ under a nitrogen atmosphere for 1.5-2.5 h.

4. The preparation method according to claim 1, characterized in that, After pyrolysis in step b, the sample is cooled to room temperature, ground, and then passed through a 200-mesh sieve. The sieve residue is then washed 2-4 times each with water and anhydrous ethanol, and dried to obtain the biochar catalyst material.

5. The biochar catalyst material for the synergistic pyrolysis of coking sludge and soybean meal prepared by the preparation method according to any one of claims 1 to 4.

6. A method for preparing a biochar catalytic membrane for the co-pyrolysis of coking sludge and soybean meal, characterized in that, Includes the following steps: Step S1: Dissolve polyvinylidene fluoride and polyvinylpyrrolidone in N,N-dimethylformamide solution, stir continuously to form a uniform casting solution, and then remove air bubbles to obtain the support layer solution. Step S2: Disperse the biochar catalytic material as described in claim 5 with PVDF and PVP in a DMF solution, stir continuously, remove the air bubbles after stirring to obtain a biochar coating solution, which serves as the catalytic layer; Step S3: The PVDF support solution and the biochar coating solution are successively coated onto the nonwoven fabric to achieve in-situ co-casting. After co-casting, the membrane is immersed in pure water to complete phase separation, thereby obtaining a biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal.

7. The preparation method according to claim 6, characterized in that, In step S1, the mass concentration of PVDF in the PVDF-supported solution ranges from 15-25 wt%; the mass concentration of PVP ranges from 1-5 wt%. In step S2, the biochar coating solution contains biochar catalyst with a mass concentration range of 1-5 wt%, PVDF with a mass concentration of 7-9 wt%, and PVP with a mass concentration of 1-3 wt%.

8. The preparation method according to claim 6, characterized in that, Mechanical stirring is used in steps S1 and S2, with stirring parameters of 150-300 rpm and 8-12 hours. The removal of air bubbles specifically involves: standing in an oven at 30-50 ℃ for 3-6 hours; or removing air bubbles by ultrasound at a frequency of 20-40 kHz for 20-30 min. After co-casting in step S3, the mixture is immersed in pure water for 6-12 hours to complete phase separation.

9. The biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal prepared by the preparation method according to any one of claims 6 to 8.

10. The application of the biochar catalytic material for the synergistic pyrolysis of coking sludge and soybean meal as described in claim 5, or the biochar catalytic membrane for the synergistic pyrolysis of coking sludge and soybean meal as described in claim 9, in the degradation of pollutants in wastewater.

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