Method for preparing phosphorus-doped bone black catalyst and deeply treating coking wastewater

Abstract

The invention relates to a method for preparing a phosphorus-doped bone charcoal catalyst and deeply treating coking wastewater, phosphorus-modified animal bone charcoal is formed by doping phosphorus in animal bone charcoal, and the phosphorus-modified animal bone charcoal is used for activating peroxyacetic acid to treat biochemical effluent of the coking wastewater. The phosphorus-doped bone charcoal has the advantages that the micro-nano structure of the bone charcoal is remarkably improved by phosphorus doping, so that the phosphorus-doped bone charcoal has higher specific surface area and porosity than other biochar, and shows an adsorption effect on nonbiodegradable organic matters in coking wastewater superior to that of other bone charcoal. The phosphorus-doped bone charcoal activated peracetic acid is adopted to deeply treat the coking wastewater, compared with an existing carbon material, the phosphorus-doped bone charcoal material is wide in source, the secondary pollution problem caused by a traditional metal-doped bone charcoal material, such as high toxicity of iron sludge and cobalt ions, is solved, the porous bone charcoal is prepared through nonmetal doping, and the application prospect is wide. The specific surface area of the material can be increased, and active sites are increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of coking wastewater treatment, and particularly relates to a method for preparing a phosphorus-doped bone char catalyst and deeply treating coking wastewater. Background Art

[0002] Coke, as a representative product of the traditional coal chemical industry, plays an important role in the steel industry. However, as a highly polluting and water-consuming industry, a large amount of wastewater is generated in each process of coal coking. Therefore, coking wastewater has a large production volume, high pollutant concentration and great treatment difficulty, and is recognized as difficult-to-treat industrial wastewater. The composition of coking wastewater is complex, and its organic components are mainly phenolic compounds, nitrogen-containing heterocyclic compounds and polycyclic aromatic hydrocarbons. In addition, coking wastewater also contains inorganic pollutants such as ammonia, cyanide and thiocyanate, as well as heavy metals. It is very difficult for the coking wastewater treated by the conventional biological treatment method to meet the standards, and pollutants that are difficult to biodegradable such as polycyclic aromatic hydrocarbons, alkylphenols and amines still remain in the biochemical effluent, so the biochemical wastewater needs to be deeply treated. It is very necessary to develop an efficient, green, universal and low-cost coking wastewater deep treatment technology.

[0003] Advanced oxidation processes (AOPs) can generate reactive species to in-situ degrade and mineralize organic matter, which is one of the effective means to decompose organic micropollutants. Common oxidants include hydrogen peroxide (H2O2), persulfate (PDDS), and peroxymonosulfate (PMS), etc. In recent years, peracetic acid (PAA) has also been applied in the purification of sewage by advanced oxidation processes as an efficient and economical oxidant. PAA has a relatively high redox potential (1.06 - 1.96 eV). It has a similar O-O bond to persulfate and hydrogen peroxide, but its bond dissociation energy is lower than that of other oxidants. Therefore, it can generate various free radicals including hydroxyl radicals and organic radicals. The lower toxicity and higher selectivity make peracetic acid a new advanced oxidation system with great development potential. The advanced oxidation technology based on PAA has the characteristic of high synchronous disinfection ability while degrading organic pollutants, so PAA has certain advantages in the treatment of medical wastewater. In the prior art, the patent publication number: CN117776371A discloses a method for treating medical wastewater by activating peracetic acid with iron-nitrogen co-doped biochar, using iron-nitrogen co-doped biochar as the material for activating peracetic acid, but the material synthesis process is relatively cumbersome, requires the addition of an additional reducing agent, and directly adds peracetic acid to complete the reaction. The patent publication number: CN117619365A discloses a supported iron biochar, its preparation method and application, using straw as the biochar raw material and the hydrates of ferric chloride, ferric sulfate, and ferric nitrate as the iron source, and obtaining the supported iron biochar through one-step high-temperature calcination. It can effectively improve the treatment efficiency of sulfonamide antibiotic wastewater, but this invention needs to directly add peracetic acid to complete the reaction, and at the same time, the catalyst contains iron elements, which has the risk of secondary pollution.

[0004] The activation pathways of PAA mainly include activation through external energy input (for example, thermal activation, ultraviolet activation, and photocatalysis, etc.), and activation through homogeneous / heterogeneous catalysts. Since the cost of activation methods using high-energy inputs such as ultraviolet light is relatively high, relatively speaking, using catalysts to activate PAA is more economically viable. Among them, heterogeneous metal-based catalysts have been widely concerned due to their advantages such as high catalytic activity, convenient recycling, and less affected by water quality.

[0005] Although peracetic acid is a promising oxidant, it is limited by its strong pungent odor, volatility, explosion hazard at low temperatures and concentrations exceeding 45%, instability, difficulty in transportation, and the need for continuous titration to determine its concentration. Therefore, a new activation method is urgently needed to solve this problem. The combined use of solid oxygen-based activators and peroxides to in-situ generate peracetic acid, followed by activation using a catalyst to achieve pollutant degradation, not only avoids the risks associated with direct addition of peracetic acid but also features safe and convenient operation, higher utilization efficiency of peracetic acid, strong stability, a wide pH range of applicability, and the ability to avoid acidification of the effluent, showing great potential for application. Summary of the Invention

[0006] To overcome the deficiencies of the prior art, the object of the present invention is to provide a method for preparing a phosphorus-doped bone char catalyst and for the advanced treatment of coking wastewater, which uses phosphorus-doped bone char to activate peracetic acid to economically and efficiently treat coking wastewater and solve the problems of difficult degradation and organic matter treatment in existing coking wastewater treatment processes.

[0007] To achieve the above object, the present invention is realized through the following technical solutions:

[0008] A method for preparing a phosphorus-doped bone char catalyst, wherein the phosphorus-doped bone char is bone char doped with nitrogen element; the preparation process includes the following steps:

[0009] 1) Preparation of bone powder slurry: Animal bones are subjected to high-temperature treatment, crushed, and ground to obtain bone powder; the bone powder is mixed with a solvent, stirred, and ultrasonicated to obtain a bone powder slurry.

[0010] 2) Preparation of bone char precursor powder: A phosphorus-containing compound is added to the bone powder slurry obtained in step 1), stirred at a constant temperature until dried, and ground to obtain bone char precursor powder.

[0011] 3) Pre-carbonization of bone: The bone char precursor powder obtained in step 2) is subjected to a high-temperature pre-reaction, ground, washed with alcohol, and dried to obtain pre-carbonized bone char.

[0012] 4) Preparation of phosphorus-doped bone char: The pre-carbonized bone char obtained in step 3) is ground, calcined under an inert atmosphere, ground, pickled, washed with alcohol, and dried to obtain phosphorus-doped bone char.

[0013] In step 1), the nitrogen dry weight content in the animal bones is 5% - 7%, and the potassium dry weight content is 0.5% - 1.2%.

[0014] The high-temperature treatment described in step 1) is boiling in boiling water for 1 to 3 hours, and then draining; the grinding is ball milling, and the ball milling conditions are: the ball milling speed is 600 to 800 r / min, the ball milling time is 120 to 240 min, and the ball-to-material ratio is 50 to 100:1; the particle size of the bone meal is 0.5 to 2.5 mm; the stirring is carried out under the condition of a rotation speed of 600 to 800 r / min; the stirring time is 60 to 90 min; the ultrasonic time is 20 to 30 min.

[0015] In step 1), the dosage of bone meal is 3 to 5 g, the solvent is deionized water or ethanol, and the dosage is 50 to 100 ml; in step 2), the phosphorus-containing compound is sodium hypophosphite, ammonium hydrogen phosphate or hydroxyethane bisphosphonic acid, and the addition amount of the phosphorus-containing compound is 1.05 to 1.35 g.

[0016] The high-temperature pre-reaction in step 3) is calcination in a muffle furnace, the calcination temperature is 250 to 350 °C, the heating rate is 2 to 5 °C / min, and the calcination time is 90 to 150 min.

[0017] The calcination under an inert atmosphere in step 4) is calcination in a tubular furnace under an inert gas atmosphere. The inert gas is nitrogen, argon or helium, the gas flow rate is 0.3 to 0.5 L / min, the calcination temperature is 550 to 750 °C, the heating rate is 5 to 15 °C / min, and the calcination time is 2 to 3 h; the grinding time is 20 to 40 min; the acid used for pickling is glacial acetic acid, hydrochloric acid or sulfuric acid; the drying temperature is 60 to 80 °C, and the drying time is 12 to 20 h.

[0018] The conditions for constant-temperature stirring and evaporation to dryness in step 2) are: temperature 90 to 105 °C, stirring speed 700 to 900 r / min; the grinding time is 10 to 30 min.

[0019] A method for the advanced treatment of coking wastewater uses phosphorus-doped bone char to activate peracetic acid to treat the biochemical effluent of coking wastewater. The treatment method of the coking wastewater includes the following steps:

[0020] 1) Preparation of a phosphorus-doped bone char membrane: Dissolve phosphorus-doped bone char in an organic solvent, disperse it by ultrasonic wave, vacuum filter the obtained phosphorus-doped bone char dispersion liquid onto a polypropylene membrane, wash it with alcohol, and dry it to obtain a phosphorus-doped bone char membrane;

[0021] 2) Coking wastewater degradation reaction: Fix the phosphorus-doped bone char membrane to a membrane module, and use the biochemical effluent of coking wastewater added with an oxygen-based surfactant and a peroxide as the feed liquid for cyclic catalytic degradation reaction.

[0022] The organic solvent described in step 1) is one of dimethylformamide, N,N-dimethylacetamide, and glycerol;

[0023] In the feed liquid described in step 2), the oxygen-based surfactant is tetraacetylethylenediamine with a concentration of 5 mM to 10 mM; the peroxide is sodium percarbonate with a concentration of 5 mM to 10 mM.

[0024] In step 3), the feed liquid enters the reaction vessel in a top-down manner, and a water circulation is driven by a circulation pump in the reactor. The reaction time is 3 h to 6 h, and the output pressure of the circulation pump is 0.05 to 0.1 bar.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1) In the present invention, phosphorus doping significantly improves the micro-nano structure of bone char, making the phosphorus-doped bone char have a higher specific surface area and porosity than other biochars, and showing an adsorption effect superior to other bone chars for the refractory biodegradable organic matter in coking wastewater.

[0027] 2) The present invention uses phosphorus-doped bone char to activate peracetic acid for the deep treatment of coking wastewater. Compared with the existing carbon materials, the source of the phosphorus-doped bone char material is wide, and it overcomes the secondary pollution problems caused by traditional metal-doped bone carbon materials, such as iron sludge, high toxicity of cobalt ions, etc. Porous carbon bone carbon is prepared by non-metal doping, which can increase the specific surface area of the material and increase the active sites.

[0028] 3) The combination of phosphorus-doped bone char and the membrane can activate the in-situ generated peracetic acid, avoiding the safety problems of directly adding peracetic acid and the problem of effluent acidification, and at the same time facilitating the recycling of phosphorus-doped bone char. Brief Description of the Drawings

[0029] Figure 1 It is a graph of the COD of the biochemical effluent of coking wastewater degraded by phosphorus-doped bone char activating peracetic acid in Examples 4 - 6. Detailed Embodiments

[0030] The present invention will be described in detail below with reference to the drawings of the specification, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0031] The materials and instruments used in the following examples are all commercially available, and the raw materials are of analytical grade. In the following examples, unless otherwise specified, the obtained data are the averages of more than three repeated experiments.

[0032] Example 1

[0033] This example provides a preparation method of phosphorus-modified bovine bone char, specifically as follows:

[0034] S1. Take animal bones with a nitrogen dry weight content of 5.03% and a potassium dry weight content of 0.65%, boil them in boiling water for 1 h, air dry naturally, crush them, place them in a ball mill, and ball mill for 120 min under the conditions of a ball-to-material ratio of 50:1 and a rotation speed of 600 r / min to obtain bone powder with a particle size of 2.5 mm; bovine bones can be selected as the animal bones.

[0035] Take 3 g of the obtained powder and mix it with 50 ml of ethanol, continuously stir at a rotation speed of 600 r / min for 60 min, and then perform ultrasonic treatment for 25 min to obtain a bone powder slurry.

[0036] S2. Add 1.05 g of sodium hypophosphite to the bone powder slurry obtained in step S1, carry out constant-temperature stirring and evaporation to dryness at 90 °C and a rotation speed of 900 r / min, and grind the obtained material for 10 min to obtain a bone char precursor powder.

[0037] S3. Transfer the bone char precursor powder obtained in step S2 to a crucible and place it in a muffle furnace, heat it up to 250 °C at a heating rate of 2 °C / min, and calcine it at 250 °C for 150 min to obtain pre-carbonized bone char.

[0038] S4. After grinding the pre-carbonized bone char obtained in step S3 for 20 min, transfer the pre-carbonized bone char to a crucible and place it in a tube furnace. Under a nitrogen atmosphere with a gas flow rate of 0.5 L / min, heat it up to 650 °C at a heating rate of 5 °C / min, and calcine it at 650 °C for 150 min, cool it, grind it into components, wash it with glacial acetic acid and then with alcohol, and dry it at 60 °C for 20 h to obtain phosphorus-doped bone char, denoted as P / BBC650.

[0039] Example 2

[0040] This example provides a method for preparing phosphorus-doped bone char, specifically as follows:

[0041] S1. Take animal bones with a nitrogen dry weight content of 5.99% and a potassium dry weight content of 1.13%, boil them in boiling water for 2 h, air dry naturally, crush them, place them in a ball mill, and ball mill for 180 min under the conditions of a ball-to-material ratio of 75:1 and a rotation speed of 700 r / min to obtain bone powder with a particle size of 1.5 mm;

[0042] Take 4 g of the obtained bone powder and mix it with 75 ml of deionized water, continuously stir at a rotation speed of 700 r / min for 75 min, and then perform ultrasonic treatment for 25 min to obtain a bone powder slurry.

[0043] S2. Add 1.15 g of diammonium hydrogen phosphate to the bone powder slurry obtained in step S1, carry out constant-temperature stirring and evaporation to dryness at 105 °C and a rotation speed of 700 r / min, and grind the obtained material for 30 min to obtain a bone char precursor powder.

[0044] S3. Transfer the bone char precursor powder obtained in step S2 to a crucible and place it in a muffle furnace. Heat it at a heating rate of 4 °C / min to 350 °C and calcine it at 350 °C for 120 min to obtain pre-carbonized bone char.

[0045] S4. After grinding the pre-carbonized bone char obtained in step S3 for 30 min, transfer the pre-carbonized bovine bone char to a crucible and place it in a tubular furnace. Under an argon atmosphere with a gas flow rate of 0.4 L / min, heat it at a heating rate of 10 °C / min to 750 °C and calcine it at 750 °C for 120 min. Cool it, grind it into components, pickling with hydrochloric acid, washing with alcohol, and then dry it at 70 °C for 16 h to obtain phosphorus-doped bone char, denoted as P / BBC750.

[0046] Example 3

[0047] This example provides a method for preparing phosphorus-doped bone char, specifically as follows:

[0048] S1. Take animal bones with a nitrogen dry weight content of 6.74% and a potassium dry weight content of 1.07%, boil them in boiling water for 3 h, air dry them naturally, crush them, place them in a ball mill, and ball mill them for 240 min under the conditions of a ball-to-material ratio of 100:1 and a rotation speed of 800 r / min to obtain bone powder with a particle size of 0.5 mm.

[0049] Take 5 g of the obtained bone powder and mix it with 100 ml of ethanol. Continuously stir it at a rotation speed of 800 r / min for 90 min, and then perform ultrasonic treatment for 30 min to obtain a bone powder slurry.

[0050] S2. Add 1.35 g of hydroxyethylidene diphosphonic acid to the bone powder slurry obtained in step S1, continuously stir and evaporate it to dryness at 100 °C and a rotation speed of 800 r / min, and grind the obtained material for 20 min to obtain bone char precursor powder.

[0051] S3. Transfer the bone char precursor powder obtained in step S2 to a crucible and place it in a muffle furnace. Heat it at a heating rate of 5 °C / min to 300 °C and calcine it at 300 °C for 90 min to obtain pre-carbonized bone char.

[0052] S4. After grinding the pre-carbonized bone char obtained in step S3 for 40 min, transfer the pre-carbonized bone char to a crucible and place it in a tubular furnace. Under a nitrogen atmosphere with a gas flow rate of 0.3 L / min, heat it at a heating rate of 15 °C / min to 550 °C and calcine it at 550 °C for 180 min. Cool it, grind it into components, pickling with sulfuric acid, washing with alcohol, and then dry it at 80 °C for 12 h to obtain phosphorus-doped bone char, denoted as P / BBC550.

[0053] Example 4

[0054] Method for deeply treating coking wastewater by peracetic acid synthesized in-situ activated by phosphorus-doped bone char, specifically as follows:

[0055] T1. Dissolve the P / BBC550 biochar prepared in Example 1 in 100 ml to 150 ml of dimethylformamide, and ultrasonicate for 30 min. Vacuum filter the uniformly dispersed P / BBC550 biochar solution onto a polypropylene filter membrane. After alcohol washing, dry it at 80 °C for 12 h to obtain a phosphorus-modified bovine bone char filter membrane.

[0056] T2. Fix the phosphorus-doped bone char filter membrane onto a membrane module. Use the biochemical effluent of coking wastewater containing tetraacetylethylenediamine and sodium percarbonate as the feed liquid. The concentration of tetraacetylethylenediamine in the feed liquid is 5 mM, and the concentration of sodium percarbonate is 5 mM. Use a circulation pump to perform a circulating catalytic degradation reaction from top to bottom with a hydraulic driving force of 0.05 bar. Take the filtrate after the filter membrane at regular intervals for COD concentration testing, and the data is as shown in the appendix Figure 1 as follows.

[0057] Use the same method to deeply treat the biochemical effluent of coking wastewater with P / BBC650 and P / BBC750, and perform COD concentration testing on the treated filtrate. The data is as shown in the appendix Figure 1 as follows.

[0058] Example 5

[0059] Method for deeply treating coking wastewater by peracetic acid synthesized in-situ activated by phosphorus-doped bone char, specifically as follows:

[0060] T1. Dissolve the P / BBC550 biochar prepared in Example 1 in 100 ml to 150 ml of N,N-dimethylacetamide, and ultrasonicate for 45 min. Vacuum filter the uniformly dispersed P / BBC550 biochar solution onto a polypropylene filter membrane. After alcohol washing, dry it at 70 °C for 16 h to obtain a phosphorus-doped bone char filter membrane.

[0061] T2. Fix the phosphorus-doped bone char filter membrane onto a membrane module. Use the biochemical effluent of coking wastewater containing tetraacetylethylenediamine and sodium percarbonate as the feed liquid. The concentration of tetraacetylethylenediamine in the feed liquid is 7.5 mM, and the concentration of sodium percarbonate is 7.5 mM. Use a circulation pump to perform a circulating catalytic degradation reaction from top to bottom with a hydraulic driving force of 0.1 bar. Take the filtrate after the filter membrane at regular intervals for COD concentration testing, and the data is as shown in the appendix Figure 1 as follows.

[0062] Use the same method to deeply treat the biochemical effluent of coking wastewater with P / BBC650 and P / BBC750, and perform COD concentration testing on the treated filtrate. The data is as shown in the appendix Figure 1 as follows.

[0063] Example 6

[0064] A method for deeply treating coking wastewater by activating in-situ synthesized peracetic acid with phosphorus-doped bone char, specifically as follows:

[0065] T1. Dissolve the P / BBC550 biochar prepared in Example 1 in 100 ml to 150 ml of glycerol, and ultrasonicate for 60 min. Vacuum filter the uniformly dispersed P / BBC550 biochar solution onto a polypropylene filter membrane. After alcohol washing, dry it at 60 °C for 20 h to obtain a phosphorus-doped bone char filter membrane.

[0066] T2. Fix the phosphorus-doped bone char filter membrane to the membrane module. Use the coking wastewater biochemical effluent containing tetraacetylethylenediamine and sodium percarbonate as the feed liquid. The concentration of tetraacetylethylenediamine in the feed liquid is 10 mM, and the concentration of sodium percarbonate is 10 mM. Use a circulation pump to carry out a circulation catalytic degradation reaction from top to bottom with a hydraulic driving force of 0.1 bar. Take the filtrate after the filter membrane at regular intervals for COD concentration testing, and the data is as shown in the appendix Figure 1 shown.

[0067] Use the same method to deeply treat the coking wastewater biochemical effluent with P / BBC650 and P / BBC750, and conduct COD concentration testing on the treated filtrate. The data is as shown in the appendix Figure 1 shown.

[0068] It can be seen from Figure 1 that P / BBC750 has a better effect of activating peracetic acid than P / BBC550 and P / BBC650, and increasing the concentration of oxygen-based surfactants and peroxides is beneficial to the degradation of pollutants in coking wastewater.

[0069] The present invention uses phosphorus-doped bone char to activate peracetic acid to treat coking wastewater. Compared with existing carbon materials, the source of phosphorus-doped bone char is wide, it does not contain metal components, and there is no problem of secondary pollution. In addition, the combination of phosphorus-modified bovine bone char and the membrane can activate in-situ generated peracetic acid, avoiding the safety problem of directly adding peracetic acid and the problem of effluent acidification, and at the same time facilitating the recycling of phosphorus-modified bovine bone char.

Claims

1. A method for preparing a phosphorus-doped bone char catalyst, characterized in that: The phosphorus-doped bone char is bone char doped with phosphorus; the preparation process comprises the following steps: 1) Preparing bone powder slurry: subjecting animal bones to high temperature treatment, crushing, and grinding to obtain bone powder; mixing the bone powder with a solvent, stirring, and ultrasonicating to obtain bone powder slurry; 2) preparing bone char precursor powder: adding a phosphorus-containing compound to the bone powder slurry obtained in step 1), evaporating to dryness under constant temperature stirring, and grinding to obtain bone char precursor powder; 3) Bone pre-carbonization: subjecting the bone char precursor powder obtained in step 2) to a high-temperature pre-reaction, grinding, alcohol washing, and drying to obtain pre-carbonized bone char; 4) Preparation of phosphorus-doped bone char: grinding the pre-carbonized bone char obtained in step 3), calcining under an inert atmosphere, grinding, acid washing, alcohol washing, and drying to obtain phosphorus-doped bone char.

2. The method for preparing a phosphorus-doped bone char catalyst according to claim 1, characterized in that: The dry weight nitrogen content of the animal bones in step 1) is 5% to 7%, and the dry weight potassium content is 0.5% to 1.2%.

3. The method for preparing a phosphorus-doped bone char catalyst according to claim 1, characterized in that: The high-temperature treatment in step 1) is boiling in boiling water for 1 to 3 hours and then draining; the grinding is ball milling, and the ball milling conditions are: ball milling speed of 600 to 800 r / min, ball milling time of 120 to 240 min, and ball-to-material ratio of 50 to 100:1; the particle size of the bone powder is 0.5 to 2.5 mm; the stirring is carried out at a speed of 600 to 800 r / min; the stirring time is 60 to 90 min; and the ultrasonic time is 20 to 30 min.

4. The method for preparing a phosphorus-doped bone char catalyst according to claim 1, characterized in that: In step 1), the amount of bone powder used is 3-5 g, and the solvent is deionized water or ethanol, and the amount used is 50-100 ml; in step 2), the phosphorus-containing compound is sodium hypophosphite, ammonium hydrogen phosphate or hydroxyethyl diphosphonic acid, and the amount of the phosphorus-containing compound added is 1.05-1.35 g.

5. The method for preparing a phosphorus-doped bone char catalyst according to claim 1, characterized in that: Step 3) The high-temperature pre-reaction is calcined in a muffle furnace at a calcination temperature of 250-350° C., a heating rate of 2-5° C. / min, and a calcination time of 90-150 min.

6. The method for preparing a phosphorus-doped bone char catalyst according to claim 1, characterized in that: Step 4) The calcination under an inert atmosphere is calcined in a tube furnace under an inert gas atmosphere, the inert gas is nitrogen, argon or helium, the gas flow rate is 0.3 to 0.5 L / min, the calcination temperature is 550 to 750°C, the heating rate is 5 to 15°C / min, and the calcination time is 2 to 3 hours; the grinding time is 20 to 40 minutes; the pickling acid is glacial acetic acid, hydrochloric acid or sulfuric acid; the drying temperature is 60 to 80°C, and the drying time is 12 to 20 hours.

7. The method for preparing a phosphorus-doped bone char catalyst according to claim 1, characterized in that: Step 2) The conditions for the constant temperature stirring and evaporation are: temperature 90-105° C., stirring speed 700-900 r / min; and grinding time 10-30 min.

8. A method for deep treatment of coking wastewater using the phosphorus-doped bone char catalyst prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The biochemical effluent of coking wastewater is treated by activating peracetic acid with phosphorus-doped bone char. The treatment method of the coking wastewater comprises the following steps: 1) Preparing a phosphorus-doped bone char filter membrane: dissolving the phosphorus-doped bone char in an organic solvent, ultrasonically dispersing the resulting phosphorus-doped bone char dispersion, vacuum filtering the resulting phosphorus-doped bone char dispersion onto a polypropylene filter membrane, washing with alcohol, and drying to obtain the phosphorus-doped bone char filter membrane; 2) Degradation reaction of coking wastewater: The phosphorus-doped bone char filter membrane is fixed to the membrane assembly, and the biochemical effluent of coking wastewater with added oxygen-based active agents and peroxides is used as the feed liquid to carry out a cyclic catalytic degradation reaction.

9. The method for deep treatment of coking wastewater according to claim 8, characterized in that: The organic solvent in step 1) is one of dimethylformamide, N,N-dimethylacetamide, and glycerol; In step 2), in the feed solution, the oxygen-based active agent is tetraacetylethylenediamine with a concentration of 5 mM to 10 mM; and the peroxide is sodium percarbonate with a concentration of 5 mM to 10 mM.

10. The method for deep treatment of coking wastewater according to claim 8, characterized in that: Step 3) The feed liquid enters the reaction vessel from top to bottom, and a circulation pump is used to drive water circulation in the reactor. The reaction time is 3h to 6h, and the output pressure of the circulation pump is 0.05 to 0.1 bar.

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