Preparation method of boron-doped bone black catalyst and method for pretreating coking wastewater

Abstract

The invention belongs to the technical field of coking wastewater treatment, and particularly relates to a method for preparing a boron-doped bone black catalyst and pretreating coking wastewater, boron-doped bone black is bone black doped with boron, and the method comprises the following steps: 1, preparing bone meal slurry: performing high-temperature treatment on animal bones, and crushing and grinding to obtain bone meal; bone meal and deionized water are mixed, stirred and subjected to ultrasonic treatment; 2, preparing bone black precursor powder: adding a boron-containing compound into the bone powder slurry, stirring at a constant temperature, evaporating to dryness, and grinding; 3) bone pre-carbonization: performing high-temperature pre-reaction on the bone black precursor powder; and grinding, calcining in an inert atmosphere, grinding, pickling, alcohol washing and drying to obtain the boron-doped bone black. The boron-doped bovine bone charcoal has the advantages that the micro-nano structure of the bone charcoal is remarkably improved by boron doping, the formation of BCO2 and BC2O in the bone charcoal is promoted by boron doping, and the mesopore and macropore ratio of the bovine bone charcoal is increased, so that the boron-doped bovine bone charcoal is an irregular particle with a rough surface and a hierarchical pore structure.

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 boron-doped bone char catalyst and pretreating 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 high 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. The COD of coking wastewater treated by existing conventional biological treatment methods is difficult to meet the standard stably, and there are still pollutants such as polycyclic aromatic hydrocarbons, alkylphenols, and amines that are difficult to biodegradable in the effluent. In addition to advanced treatment, strengthening pretreatment is an effective method. At present, some pretreatment of coking wastewater mainly adds a primary biochemical pretreatment before the biochemical system, which has high investment, high operating cost, and difficulty in screening special bacteria. Using chemical catalytic methods can not only reduce the investment and operation and maintenance costs, but more importantly, there is no need to worry about the impact of the toxicity of the incoming coking wastewater on the system.

[0003] Advanced oxidation processes (AOPs) can generate reactive species to in-situ degrade and mineralize organic matters, which are one of the effective means to decompose organic micropollutants. Common oxidants include hydrogen peroxide (H2O2), peroxydisulfate (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. 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 and killing ability while degrading organic pollutants. 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. However, the material synthesis process is relatively cumbersome, an additional reducing agent needs to be added, and peracetic acid needs to be directly added to complete the reaction. The patent publication number: CN117619365A discloses a supported iron biochar and its preparation method and application, using straw as the biochar raw material and 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. However, this invention needs to directly add peracetic acid to complete the reaction, and 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 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, high volatility, tendency to explode at low temperatures and concentrations exceeding 45%, instability, difficulty in transportation, and the need for continuous titration to determine its concentration. Therefore, there is an urgent need for a new activation method to solve this problem. Using solid oxygen-based activators and peroxides to generate peracetic acid in situ and then using a catalyst for activation to achieve pollutant degradation not only avoids the risks associated with directly adding peracetic acid but also has the characteristics of safe and convenient operation, higher utilization efficiency of peracetic acid, strong stability, a wide pH application range, and the ability to avoid acidification of the effluent, showing great application potential. Summary of the Invention

[0006] To overcome the deficiencies of the prior art, the purpose of the present invention is to provide a method for preparing a boron-doped bone char catalyst and pretreating coking wastewater, which uses boron-doped bone char to activate peracetic acid to economically and efficiently treat coking wastewater and solve the problem that the COD in the existing coking wastewater treatment process cannot reach the standard stably.

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

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

[0009] 1) Prepare a bone powder slurry: subject animal bones to high-temperature treatment, then crush and grind them to obtain bone powder; mix the bone powder with deionized water, stir, and sonicate to obtain a bone powder slurry;

[0010] 2) Prepare bone char precursor powder: add a boron-containing compound to the bone powder slurry obtained in step 1), stir at a constant temperature until dry, and grind to obtain bone char precursor powder;

[0011] 3) Pre-carbonize the bone: subject the bone char precursor powder obtained in step 2) to a high-temperature pre-reaction to obtain pre-carbonized bone char;

[0012] 4) Prepare boron-doped bone char: grind the pre-carbonized bone char obtained in step 3), calcine it under an inert atmosphere, grind it, wash it with acid, wash it with alcohol, and dry it to obtain boron-doped bone char.

[0013] The amorphous carbon content in the animal bones in step 1) is 9% - 13%.

[0014] The high-temperature treatment described in step 1) is boiling in water for 1 to 3 h 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 at a speed of 600 to 800 r / min; the stirring time is 60 to 90 min; the ultrasonic time is 20 to 30 min.

[0015] The amount of the bone meal is 3 to 5 g, the amount of deionized water is 50 to 100 ml; the boron-containing compound is 1.05 to 2.22 g; the boron-containing compound is sodium borohydride, potassium borohydride or sodium tetraborate.

[0016] The high-temperature pre-reaction described in step 3) is calcination in a muffle furnace, and the calcination conditions are: the temperature is 300 to 450 °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 described 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 800 to 900 °C, the heating rate is 5 to 15 °C / min, and the calcination time is 2 to 4 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 described in step 2) are: temperature 60 to 70 °C, stirring speed 1000 to 1200 r / min; the grinding time is 10 to 30 min.

[0019] A method for pretreating coking wastewater uses a boron-doped bone char catalyst to activate peracetic acid for pretreating coking wastewater; the treatment method of the coking wastewater includes the following steps:

[0020] 1) Preparation of a boron-doped bone char filter membrane: Dissolve the boron-doped bone char in an organic solvent, and ultrasonically disperse to obtain a dispersion; Vacuum filter the dispersion onto a filter membrane, wash with alcohol, and dry to obtain a boron-doped bone char filter membrane;

[0021] 2) Coking wastewater degradation reaction: Fix the boron-doped bone char filter membrane to a membrane module, and use the ammonia-steaming wastewater added with an oxygen-based surfactant and a peroxide as the feed liquid to carry out a cyclic catalytic degradation reaction.

[0022] The organic solvent is one of dimethylformamide, N,N-dimethylacetamide, and glycerol; the oxygen-based surfactant is tetraacetylethylenediamine, and the concentration is 5 to 10 mM; the peroxide is sodium percarbonate, and the concentration is 5 to 10 mM;

[0023] The feed liquid enters the reaction vessel in a top-down manner, and the reaction time is 3h to 6h;

[0024] The ultrasonic dispersion time is 30min to 60min, and the drying conditions are: the temperature is 60 - 80°C, and the drying time is 12 - 20h; The cyclic degradation reaction uses a circulating pump to drive the water circulation at a pressure of 0.05 - 0.1 bar.

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

[0026] 1) In the present invention, boron doping significantly improves the micro-nano structure of bone char. Boron doping promotes the formation of BCO2 and BC2O in bone char, greatly increasing the proportion of mesopores and macropores in bone char, making the boron-doped bone char irregular granular with a rough surface and a hierarchical pore structure. Boron-doped modified biochar improves the graphitization degree of the carbon structure, increases the specific surface area, accelerates electron migration, and increases new defect edges and active sites, thereby enhancing its adsorption capacity for organic matter in ammonia distillation wastewater and the activation capacity of peracetic acid.

[0027] 2) The present invention uses boron-doped bone char to activate peracetic acid for the pretreatment of coking wastewater. Compared with existing carbon materials, the boron-modified bone char material has a wide source, does not contain metal components, and has no secondary pollution problem. In addition, boron-doped bone char combined with 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 is also beneficial to the recycling of boron-doped bone char. Description of the Drawings

[0028] Figure 1 It is the COD curve of the degradation of ammonia distillation wastewater by boron-doped bone char activating peracetic acid in Examples 4 - 6. Detailed Embodiments

[0029] The present invention will be described in detail below with reference to the accompanying drawings of the specification, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0030] The materials and instruments used in the following examples are all commercially available, and the raw materials are of analytical purity. In the following examples, unless otherwise specified, the obtained data are the averages of more than three repeated experiments.

[0031] Example 1

[0032] This example provides a preparation method of boron-doped bone char, specifically as follows:

[0033] S1. Take animal bones with an amorphous carbon content of 9.34% and boil them in boiling water for 1 h. Air-dry them naturally, crush them, place them in a ball mill, and ball mill for 120 min at 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. Take 3 g of the obtained bone powder and mix it with 50 ml of deionized water. 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. Bovine bones can be selected as the animal bones.

[0034] S2. Add 1.05 g of sodium borohydride to the bone powder slurry obtained in step S1, and perform constant-temperature stirring and evaporation to dryness at 60 °C and a rotation speed of 1200 r / min, and grind the obtained material for 10 min to obtain a bone char precursor powder.

[0035] 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 2 °C / min to 300 °C, and calcine it at 300 °C for 150 min to obtain pre-carbonized bone char.

[0036] 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 at a heating rate of 5 °C / min to 800 °C, and calcine it at 800 °C for 4 h. 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 boron-doped bone char, denoted as B / BBC800.

[0037] Example 2

[0038] This example provides a method for preparing boron-doped bone char, specifically as follows:

[0039] S1. Take animal bones with an amorphous carbon content of 11.63% and boil them in boiling water for 2 h. Air-dry them naturally, crush them, place them in a ball mill, and ball mill for 180 min at 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. Mix 5 g of the obtained bone powder 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.

[0040] S2. Add 2.22 g of sodium tetraborate to the bone powder slurry obtained in step S1, and perform constant-temperature stirring and evaporation to dryness at 65 °C and a rotation speed of 1100 r / min, and grind the obtained material for 20 min to obtain a bone char precursor powder.

[0041] S3. Transfer the bone char precursor powder obtained in step S2 into a crucible and place it in a muffle furnace. Heat it at a heating rate of 5 °C / min to 400 °C and calcine it at 400 °C for 120 min to obtain pre-carbonized bone char.

[0042] S4. After grinding the pre-carbonized bone char obtained in step S3 for 30 min, transfer the pre-carbonized bone char into a crucible and place it in a tube 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 850 °C and calcine it at 850 °C for 3 h. Cool it, grind it into components, wash it with hydrochloric acid and then with alcohol, and dry it at 70 °C for 16 h to obtain boron-doped bone char, denoted as B / BBC850.

[0043] Example 3

[0044] This example provides a method for preparing boron-doped bone char, specifically as follows:

[0045] S1. Take animal bones with an amorphous carbon content of 12.31% and 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. Mix 4 g of the obtained bone powder with 100 ml of deionized water, 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.

[0046] S2. Add 2.01 g of potassium borohydride to the bone powder slurry obtained in step S1, constantly stir and evaporate it to dryness at 70 °C and a rotation speed of 1000 r / min, and grind the obtained material for 30 min to obtain bone char precursor powder.

[0047] S3. Transfer the bone char precursor powder obtained in step S2 into a crucible and place it in a muffle furnace. Heat it at a heating rate of 4 °C / min to 450 °C and calcine it at 450 °C for 90 min to obtain pre-carbonized bone char.

[0048] S4. After grinding the pre-carbonized bone char obtained in step S3 for 40 min, transfer the pre-carbonized bone char into a crucible and place it in a tube 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 900 °C and calcine it at 900 °C for 2 h. Cool it, grind it into components, wash it with sulfuric acid and then with alcohol, and dry it at 80 °C for 12 h to obtain boron-doped bone char, denoted as B / BBC900.

[0049] Example 4

[0050] A method for pretreating coking wastewater with peracetic acid in-situ synthesized by activating boron-doped bone char, specifically as follows:

[0051] T1. Dissolve the B / BBC800 biochar prepared in Example 1 in 100 ml to 150 ml of dimethylformamide and sonicate for 30 min. Vacuum filter the uniformly dispersed B / BBC800 biochar solution onto a polypropylene filter membrane. After alcohol washing, dry it at 80 °C for 12 h to obtain a boron-doped bone char filter membrane.

[0052] T2. Fix the boron-doped bone char filter membrane to the membrane module. Use the ammonia stripping 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 with a driving force of 0.05 bar to conduct a cyclic catalytic degradation reaction from top to bottom. 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.

[0053] Use B / BBC850 and B / BBC900 to treat the ammonia stripping wastewater in the same way, and conduct COD concentration testing on the filtrate after treatment. The data is as shown in the appendix Figure 1 as follows.

[0054] Example 5

[0055] A method for pretreating coking wastewater with peracetic acid in-situ synthesized by activating boron-doped bone char, specifically:

[0056] T1. Dissolve the B / BBC800 biochar prepared in Example 1 in N,N-dimethylacetamide and sonicate for 45 min. Vacuum filter the uniformly dispersed B / BBC800 biochar solution onto a polypropylene filter membrane. After alcohol washing, dry it at 70 °C for 16 h to obtain a boron-doped bone char filter membrane.

[0057] T2. Fix the boron-doped bone char filter membrane to the membrane module. Use the ammonia stripping 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 with a hydraulic driving force of 0.1 bar to conduct a cyclic catalytic degradation reaction from top to bottom. 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.

[0058] Use B / BBC850 and B / BBC900 to treat the ammonia stripping wastewater in the same way, and conduct COD concentration testing on the filtrate after treatment. The data is as shown in the appendix Figure 1 as follows.

[0059] Example 6

[0060] A method for pretreating coking wastewater with peracetic acid in-situ synthesized by activating boron-doped bone char, specifically:

[0061] T1. Dissolve the B / BBC800 biochar prepared in Example 1 in glycerol and sonicate for 60 min. Vacuum filter the uniformly dispersed B / BBC800 biochar solution onto a polypropylene filter membrane. After alcohol washing, dry it at 60 °C for 20 h to obtain a boron-doped bone char filter membrane.

[0062] T2. Fix the boron-doped bone char filter membrane to the membrane module. Use the ammonia distillation wastewater 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 with a hydraulic driving force of 0.1 bar to carry out the cyclic catalytic degradation reaction from top to bottom. 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.

[0063] Use the same method to treat the ammonia distillation wastewater with B / BBC850 and B / BBC900, and conduct COD concentration testing on the filtrate after treatment. The data is as shown in the appendix. Figure 1 as follows.

[0064] It can be seen that Figure 1 B / BBC850 has a better effect of activating peracetic acid than B / BBC800 and B / BBC900. Increasing the concentration of oxygen-based surfactants and peroxides is beneficial to the degradation of pollutants in the ammonia distillation wastewater.

[0065] The present invention uses boron-doped bone char to activate peracetic acid to treat coking wastewater. Compared with existing carbon materials, the boron-doped bone char material has a wide source, does not contain metal components, and has no problem of secondary pollution. In addition, the combination of boron-doped 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 is also beneficial to the recycling of boron-doped bone char.

Claims

1. A preparation method of a boron-doped bone char catalyst, characterized in that, The boron-doped bone char is bone char doped with boron element; the preparation process includes the following steps: 1) Prepare bone powder slurry: subject animal bones to high-temperature treatment, then crush and grind to obtain bone powder; mix the bone powder with deionized water, stir and ultrasonicate to obtain bone powder slurry; 2) Prepare bone char precursor powder: add a boron-containing compound to the bone powder slurry obtained in step 1), stir at a constant temperature until dried, and grind to obtain bone char precursor powder; 3) Pre-carbonize the bone: perform a high-temperature pre-reaction on the bone char precursor powder obtained in step 2) to obtain pre-carbonized bone char; 4) Prepare boron-doped bone char: grind the pre-carbonized bone char obtained in step 3), calcine it under an inert atmosphere, grind it, wash it with acid, wash it with alcohol, and dry it to obtain boron-doped bone char.

2. The preparation method of a boron-doped bone char catalyst according to claim 1, characterized in that, In step 1), the amorphous carbon content in the animal bones is 9% - 13%.

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

4. The preparation method of a boron-doped bone char catalyst according to claim 1, characterized in that, The bone powder is 3 - 5 g, the deionized water is 50 - 100 ml; the boron-containing compound is 1.05 - 2.22 g; the boron-containing compound is sodium borohydride, potassium borohydride or sodium tetraborate.

5. The preparation method of a boron-doped bone char catalyst according to claim 1, characterized in that, In step 3), the high-temperature pre-reaction is calcination in a muffle furnace, and the calcination conditions are: the temperature is 300 - 450 °C, the heating rate is 2 - 5 °C / min, and the calcination time is 90 - 150 min.

6. The preparation method of a boron-doped bone char catalyst according to claim 1, characterized in that, In step 4), the calcination under an inert atmosphere 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 - 0.5 L / min, the calcination temperature is 800 - 900 °C, the heating rate is 5 - 15 °C / min, and the calcination time is 2 - 4 h; the grinding time is 20 - 40 min; the acid used for acid washing is glacial acetic acid, hydrochloric acid or sulfuric acid; the drying temperature is 60 - 80 °C, and the drying time is 12 - 20 h.

7. The preparation method of a boron-doped bone char catalyst according to claim 1, characterized in that, In step 2), the conditions for stirring and evaporating to dryness at a constant temperature are: the temperature is 60 - 70 °C, and the stirring speed is 1000 - 1200 r / min; the grinding time is 10 - 30 min.

8. A method for pretreating coking wastewater using a boron-doped bone char catalyst prepared by the preparation method according to any one of claims 1 to 7, characterized in that, Use the boron-doped bone char catalyst to activate peracetic acid for pretreatment of coking wastewater; the treatment method of the coking wastewater includes the following steps: 1) Prepare a boron-doped bone char filter membrane: dissolve the boron-doped bone char in an organic solvent, ultrasonically disperse to obtain a dispersion; vacuum filter the dispersion onto a filter membrane, wash it with alcohol, and dry it to obtain a boron-doped bone char filter membrane; 2) Coking wastewater degradation reaction: fix the boron-doped bone char filter membrane to a membrane module, and use the ammonia stripping wastewater added with an oxygen-based surfactant and a peroxide as the feed liquid for a cyclic catalytic degradation reaction.

9. The method for pretreating coking wastewater according to claim 8, characterized in that, The organic solvent is one of dimethylformamide, N,N-dimethylacetamide, and glycerol; the oxygen-based surfactant is tetraacetylethylenediamine with a concentration of 5 to 10 mM; the peroxide is sodium percarbonate with a concentration of 5 to 10 mM; The feed liquid enters the reaction vessel in a top-down manner, and the reaction time is 3 h to 6 h; The ultrasonic dispersion time is 30 min to 60 min, and the drying conditions are: the temperature is 60 to 80 °C, and the drying time is 12 to 20 h; The cyclic degradation reaction uses a circulating pump to drive the water circulation at a pressure of 0.05 to 0.1 bar.

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