A hydrolysis acidification wastewater treatment process for enhancing extracellular electron transfer

Abstract

The present invention relates to the technical field of wastewater treatment, and particularly to a hydrolysis acidification wastewater treatment process for enhancing extracellular electron transfer, comprising the following steps: S1. Construct a hydrolysis acidification reactor, with carbon fiber hanging fillers as the anode, a wire mesh frame as the cathode, the carbon fiber hanging fillers being connected in series by stainless steel wire ropes, and the carbon fiber hanging fillers and the wire mesh frame being connected through an electrochemical workstation; S2. Inoculate the hydrolysis acidification bacteria into the reactor, control the culture conditions, and domesticate the microorganisms in a microcurrent environment until a biofilm is formed on the carbon fiber hanging fillers; S3. Input the wastewater to be treated into the reactor, control the treatment conditions, monitor the effluent results, and discharge after reaching the standard. The wastewater treatment method of the present invention has higher efficiency and speed compared with traditional interspecies electron transfer, helps to accelerate the oxidation and decomposition process of organic substances, and improves the overall efficiency of wastewater treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a hydrolysis acidification wastewater treatment process for enhancing extracellular electron transfer. Background Art

[0002] As a pretreatment step for many biological treatment processes (such as aerobic processes), the hydrolysis acidification technology not only lays a solid foundation for subsequent biochemical treatment, but also shows good performance when treating wastewater with extremely high treatment difficulty, such as pharmaceutical wastewater, printing and dyeing wastewater, paper-making wastewater, and petrochemical wastewater. The core of the hydrolysis acidification technology lies in its utilization of the metabolic characteristics of anaerobic microorganisms. These microorganisms, in an anoxic environment, through a series of complex biochemical reactions, gradually convert macromolecular organic substances such as refractory long-chain hydrocarbons and aromatic compounds into small-molecular substances such as fatty acids, alcohols, and amino acids that are easily biodegradable. This process significantly reduces the biological toxicity of the wastewater and greatly improves the biodegradability of the wastewater, making the originally difficult-to-treat wastewater more easily accepted and degraded by subsequent biological treatment processes. In addition, during the hydrolysis acidification process, part of the organic matter is removed, further reducing the burden on the subsequent treatment unit, providing more stable and high-quality influent conditions for it, and improving the treatment efficiency of the entire wastewater treatment system.

[0003] During the hydrolysis acidification process, the hydrolysis acidification bacteria participating in substrate oxidation usually rely on H 2 as an electron carrier to transfer the generated electrons to organic pollutants to achieve the reduction of their functional groups. However, the low solubility of H 2 in water severely limits the electron transfer rate and becomes one of the key factors restricting the hydrolysis acidification efficiency. In addition, when the hydrolysis acidification bacteria treat organic matter containing a large number of heterocyclic or polycyclic structures, the degradation difficulty increases significantly, and the presence of these complex organic substances further exacerbates the complexity of wastewater treatment. Summary of the Invention

[0004] In order to solve the problems mentioned in the above background art, the present invention provides a hydrolysis acidification wastewater treatment process for enhancing extracellular electron transfer.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A hydrolysis acidification wastewater treatment process for enhancing extracellular electron transfer, comprising the following steps:

[0007] S1. Construct a hydrolysis acidification reactor. The hydrolysis acidification reactor includes carbon fiber hanging fillers arranged inside the reactor and a wire mesh frame floating on the water surface. The carbon fiber hanging fillers serve as the anode, and the wire mesh frame serves as the cathode. The carbon fiber hanging fillers are connected in series as a whole by stainless steel wire ropes. The distance between the upper and lower carbon fiber hanging fillers is 50 - 80 mm, forming several groups of modular fillers, which are stacked inside the reactor to form a modular structure. The carbon fiber hanging fillers and the wire mesh frame are connected through an electrochemical workstation. The carbon fiber fillers and the electrochemical workstation are connected by copper wires to form a closed circuit;

[0008] S2. Inoculate the hydrolysis acidification bacteria in the existing biological treatment system into the reactor, control the culture conditions, promote the growth of microorganisms, and culture and domesticate the microorganisms in a micro-current environment until a biofilm is formed on the carbon fiber hanging fillers;

[0009] S3. Input the wastewater to be treated into the reactor, control the treatment conditions, monitor the effluent results, and discharge after reaching the standard.

[0010] Furthermore, the carbon fiber hanging fillers in step S1 are prepared through the following steps:

[0011] Select carbon fiber filaments with a diameter of 0.5 - 1.0 mm, clean the carbon fiber filaments with an ultrasonic cleaner for 5 - 10 min with a power of 50 - 100 W, then soak and clean them in absolute ethanol for 20 - 30 min, and then soak them in a hydrogen peroxide solution for activation. Take them out and dry them to obtain pretreated carbon fiber filaments. Immerse the pretreated carbon fiber filaments in the coating solution, let them stand or gently stir the solution several times, keep for 10 - 20 min, take out the carbon fiber filaments, blot the excess coating solution with filter paper, hang them in an oven, heat up to 100 - 110 °C, and dry for 2 - 4 h until the coating layer is cured. After cooling, obtain the carbon fiber hanging fillers.

[0012] Furthermore, the culture conditions in step S2 are specifically: the temperature is 30 ± 2 °C, the pH value is 6.5 - 7.5, and the C:N:P is maintained at 100:(5 - 5.5):(1 - 1.2).

[0013] Furthermore, the micro-current environment in step S2 is specifically: the initial current is 1 mA, and it gradually increases by 0.08 - 0.12 mA every 2 days until the final current is 5 - 5.4 mA, and the total domestication period is not less than 30 days.

[0014] Furthermore, the hydrolysis acidification bacteria include one or more of Brevibacillus stercoris, Acetobacter, Lysinibacillus, Brachybacterium russenii, Serratia, and Bacillus licheniformis.

[0015] Furthermore, the treatment conditions in step S3 are specifically: the influent flow rate is 0.4 - 0.6 m 3 / h, maintain the hydraulic retention time at 18 - 24 h, and adjust the current to 3 - 7 mA through an electrochemical workstation.

[0016] Furthermore, the concentration of the hydrogen peroxide solution is 0.1 - 0.3 mol / L, the activation temperature is 60 - 70 °C, and the activation time is 1 - 2 h.

[0017] Furthermore, the coating solution is prepared through the following steps:

[0018] A1. In a reactor equipped with a constant-pressure dropping funnel, a reflux condenser, and a nitrogen protection device, add iodine and magnesium strips, dropwise add hexyl bromide, and keep the reaction solution slightly boiling. After the dropping is complete, obtain the reaction solution. Add thiophene to absolute ethanol to obtain a thiophene solution, and slowly drop the thiophene solution into the reaction solution. After the dropping is complete, react for 24 h. After the reaction ends, hydrolyze the reaction mixture with saturated ammonium chloride solution, separate the organic layer, dry it with anhydrous sodium sulfate, and then distill to collect 3-hexylthiophene;

[0019] A2. Add 3-hexylthiophene and potassium polyphosphate to a reactor pre-filled with the solvent toluene. Under nitrogen protection, stir and dissolve until completely transparent. Add azobisisobutyronitrile and butylated hydroxyanisole, seal the reactor, place the reactor in an oil bath, heat up to 70 - 80 °C, and react for 24 - 36 h. When the reaction ends, cool to room temperature, pour it into methanol for precipitation, and filter to obtain a copolymer precipitate;

[0020] A3. Add the copolymer to N,N-dimethylformamide, stir until dissolved, add nano-titanium dioxide powder, and use an ultrasonic disperser to ultrasonically disperse for 20 - 30 min until uniformly dispersed. Stir for 1 - 2 h under magnetic stirring, filter, wash, place it in a vacuum oven at 60 °C and dry to constant weight, and then re-formulate it with N,N-dimethylformamide into a coating solution with a concentration of 40 - 50%.

[0021] Furthermore, in step A1, the mass ratio of iodine, magnesium strip, hexyl bromide, thiophene, and absolute ethanol is (0.2 - 0.3):(6.2 - 6.8):(50 - 52):(27.5 - 29):200.

[0022] Furthermore, in step A2, the mass ratio of 3-hexylthiophene, potassium polyphosphate, toluene, azobisisobutyronitrile, and butylated hydroxyanisole is (20 - 21.5):(12 - 14):100:(0.1 - 0.3):(0.05 - 0.07).

[0023] Furthermore, in step A3, the mass ratio of the copolymer, N,N-dimethylformamide, and nano-titanium dioxide powder is (10 - 11):50:(2 - 2.5).

[0024] Advantages of the present invention:

[0025] 1. In the present invention, vertically suspended carbon fiber fillers are arranged inside the hydrolysis acidification reactor, providing sufficient attachment surfaces for microorganisms, which is conducive to the rapid formation and stable maintenance of biofilms. Moreover, as an anode, the carbon fiber fillers construct a micro-current environment inside the reactor, which can selectively promote the enrichment and growth of conductive or electrophilic microorganisms. These microorganisms have higher efficiency in decomposing refractory organic matter, thus significantly improving the efficiency of the hydrolysis acidification process. In the constructed bio-microelectrolysis reaction system, microorganisms can utilize redox proteins (especially cytochromes) on the cell membrane and conductive pili and other structures to achieve direct electron transfer with the electrode, which has higher efficiency and speed compared to traditional interspecies electron transfer (such as through mediators), helping to accelerate the oxidation decomposition process of organic matter and improve the overall efficiency of wastewater treatment.

[0026] 2. In the technical solution of the present invention, the coating solution exhibits high order and functionality. The chain structure formed by the copolymerization of 3-hexylthiophene and potassium polyphosphate forms continuous conductive channels, and also provides a stable environment for the attachment of microorganisms through the hydrophobic properties of the hexyl chains. At the same time, the uniform dispersion of nano-titanium dioxide particles in the coating solution further enhances the conductivity and photocatalytic performance of the coating layer, forming a dense and functionally rich interface layer on the surface of the carbon fiber, greatly optimizing the interaction between microorganisms and the electrode. The enhanced conductivity of the copolymer and the semiconductor properties of nano-titanium dioxide jointly promote the electron transfer efficiency between microorganisms and the electrode, making the electron flow in the wastewater treatment process smoother, thereby improving the overall efficiency of wastewater treatment. Secondly, the photocatalytic performance and antibacterial effect of nano-titanium dioxide effectively inhibit the overgrowth of microorganisms, maintain the activity and stability of the biofilm, extend the operation cycle of the wastewater treatment system, and also improve the stability and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 It is a schematic structural diagram of the hydrolysis acidification reactor of the present invention;

[0029] In the figure: 1. Floating cathode; 2. Electrochemical workstation; 3. Outlet pipe; 4. Carbon fiber hanging filler; 5. Overflow pipe; 6. Sampling pipe; 7. Feed water pump; 8. Sludge discharge pipe. Detailed implementation manners

[0030] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market. The hydrolytic acidification bacteria are cultured by the method in Shao Ruying, Gao Feng, Zhang Ling, etc. Screening and application research of highly efficient hydrolytic acidification bacteria [J]. Guangdong Chemical Industry, 2022, 6(49): 67-69.

[0032] Preparation Example 1: The coating solution is prepared through the following steps:

[0033] A1. In a reactor equipped with a constant-pressure dropping funnel, a reflux condenser and a nitrogen protection device, 2 g of iodine and 62 g of magnesium strips are added, 500 g of hexyl bromide is added dropwise, and the reaction solution is kept slightly boiling. After the dropwise addition is completed, a reaction solution is obtained. 275 g of thiophene is added to 2000 g of absolute ethanol to obtain a thiophene solution. The thiophene solution is slowly added dropwise to the reaction solution. After the dropwise addition is completed, the reaction is carried out for 24 h. After the reaction is completed, the reaction mixture is hydrolyzed with a saturated ammonium chloride solution, the organic layer is separated, dried with anhydrous sodium sulfate, and then distilled to collect 3-hexylthiophene;

[0034] A2. 200 g of 3-hexylthiophene and 120 g of potassium polyphosphate are added to a reactor pre-filled with 1000 g of toluene as a solvent. Under nitrogen protection, it is stirred and dissolved until completely transparent. 1 g of azobisisobutyronitrile and 0.5 g of butylated hydroxyanisole are added. The reactor is sealed and placed in an oil bath. The temperature is raised to 70 °C and the reaction is carried out for 24 h. After the reaction is completed, it is cooled to room temperature and poured into methanol for precipitation. The copolymer precipitate is obtained by filtration;

[0035] A3. 100 g of the copolymer is added to 500 g of N,N-dimethylformamide and stirred until dissolved. 20 g of nano-titanium dioxide powder is added, and it is ultrasonicated with an ultrasonic disperser for 20 min until evenly dispersed. It is stirred under magnetic stirring for 1 h, filtered, washed, and placed in a vacuum oven at 60 °C to dry to constant weight, and then re-formulated with N,N-dimethylformamide into a coating solution with a concentration of 40%.

[0036] The carbon fiber hanging packing is prepared through the following steps:

[0037] Select carbon fiber filaments with a diameter of 0.5 mm, clean the carbon fiber filaments with an ultrasonic cleaner for 5 min at a power of 50 W, then soak and clean them with absolute ethanol for 20 min, and then soak them in a hydrogen peroxide solution with a concentration of 0.1 mol / L for activation for 1 h at a temperature of 60 °C. Take them out and dry to obtain pretreated carbon fiber filaments. Immerse the pretreated carbon fiber filaments in the prepared coating solution and let them stand for 10 min. Take out the carbon fiber filaments, gently suck off the excess coating solution with filter paper, hang them in an oven, raise the temperature to 100 °C, and dry for 2 h until the coating layer is cured. After cooling, carbon fiber hanging fillers are obtained.

[0038] Preparation Example 2: The coating solution is prepared through the following steps:

[0039] A1. In a reactor equipped with a constant-pressure dropping funnel, a reflux condenser, and a nitrogen protection device, add 2.5 g of iodine and 65 g of magnesium strips, dropwise add 510 g of hexyl bromide, and keep the reaction solution slightly boiling. After the dropping is completed, a reaction solution is obtained. Add 282 g of thiophene to 2000 g of absolute ethanol to obtain a thiophene solution. Slowly drop the thiophene solution into the reaction solution. After the dropping is completed, react for 24 h. After the reaction is completed, hydrolyze the reaction mixture with a saturated ammonium chloride solution, separate the organic layer, dry it with anhydrous sodium sulfate, and then distill to collect 3-hexylthiophene.

[0040] A2. Add 210 g of 3-hexylthiophene and 130 g of potassium polyphosphate to a reactor pre-filled with 1000 g of toluene as a solvent. Under nitrogen protection, stir and dissolve until it is completely transparent. Add 2 g of azobisisobutyronitrile and 0.6 g of butylhydroxyanisole, seal the reactor, place the reactor in an oil bath, raise the temperature to 75 °C, and react for 30 h. When the reaction is completed, cool to room temperature, pour it into methanol for precipitation, and filter to obtain a copolymer precipitate.

[0041] A3. Add 105 g of the copolymer to 500 g of N,N-dimethylformamide, stir until it is dissolved, add 22.5 g of nano-titanium dioxide powder, disperse it evenly by ultrasonic dispersion for 25 min with an ultrasonic disperser, stir for 1.5 h under magnetic stirring, filter, wash, place it in a vacuum oven at 60 °C and dry to constant weight, and then re-prepare it into a coating solution with a concentration of 45% with N,N-dimethylformamide.

[0042] The carbon fiber hanging fillers are prepared through the following steps:

[0043] Select carbon fiber filaments with a diameter of 0.8 mm. Clean the carbon fiber filaments with an ultrasonic cleaner for 8 min at a power of 60 W. Then soak and clean them with absolute ethanol for 25 min. Next, soak them in a hydrogen peroxide solution with a concentration of 0.15 mol / L for activation for 1.5 h at a temperature of 63 °C. Take them out and dry to obtain pretreated carbon fiber filaments. Immerse the pretreated carbon fiber filaments in the coating solution, let it stand or gently stir the solution several times, keep it for 15 min, take out the carbon fiber filaments, gently blot the excess coating solution with filter paper, hang them in an oven, raise the temperature to 105 °C, and dry for 3 h until the coating layer is cured. After cooling, carbon fiber hanging fillers are obtained.

[0044] Preparation Example 3: The coating solution is prepared through the following steps:

[0045] A1. In a reactor equipped with a constant-pressure dropping funnel, a reflux condenser, and a nitrogen protection device, add 3 g of iodine and 68 g of magnesium strips, dropwise add 520 g of hexyl bromide, keep the reaction solution slightly boiling. After the dropping is completed, obtain the reaction solution. Add 290 g of thiophene to 2000 g of absolute ethanol to obtain a thiophene solution. Slowly drop the thiophene solution into the reaction solution. After the dropping is completed, react for 24 h. After the reaction is completed, hydrolyze the reaction mixture with a saturated ammonium chloride solution, separate the organic layer, dry it with anhydrous sodium sulfate, and then distill to collect 3-hexylthiophene;

[0046] A2. Add 215 g of 3-hexylthiophene and 140 g of potassium polyphosphate to a reactor pre-filled with 1000 g of toluene as the solvent. Under nitrogen protection, stir and dissolve until it is completely transparent. Add 3 g of azobisisobutyronitrile and 0.7 g of butylated hydroxyanisole. Seal the reactor and place the reactor in an oil bath, raise the temperature to 80 °C, and react for 36 h. When the reaction is completed, cool to room temperature, pour it into methanol for precipitation, and filter to obtain a copolymer precipitate;

[0047] A3. Add 110 g of the copolymer to 500 g of N,N-dimethylformamide, stir until it is dissolved, add 25 g of nano-titanium dioxide powder, disperse it evenly by ultrasonic wave with an ultrasonic disperser for 30 min, stir for 2 h under magnetic stirring, filter, wash, place it in a vacuum oven at 60 °C and dry to constant weight, and re-prepare it into a coating solution with a concentration of 50% with N,N-dimethylformamide.

[0048] The carbon fiber hanging fillers are prepared through the following steps:

[0049] Select carbon fiber filaments with a diameter of 1.0 mm. Clean the carbon fiber filaments with an ultrasonic cleaner for 10 min at a power of 100 W. Then soak and clean them with absolute ethanol for 30 min, and then soak them in a hydrogen peroxide solution with a concentration of 0.3 mol / L for 2 h at a temperature of 70 °C. Take them out and dry to obtain pretreated carbon fiber filaments. Immerse the pretreated carbon fiber filaments in the coating solution, let it stand or gently stir the solution several times, keep it for 20 min, take out the carbon fiber filaments, gently blot the excess coating solution with filter paper, hang them in an oven, heat up to 110 °C, and dry for 4 h until the coating layer is cured. After cooling, carbon fiber hanging fillers are obtained.

[0050] Example 1: A hydrolytic acidification wastewater treatment process for enhancing extracellular electron transfer, comprising the following steps:

[0051] S1. Construct a hydrolytic acidification reactor with dimensions of 2 m × 1 m × 2 m. Use the carbon fiber hanging fillers prepared in Preparation Example 1 as the anode and a wire mesh frame as the cathode. The carbon fiber hanging fillers are connected in series as a whole by stainless steel wire ropes, and the distance between the upper and lower carbon fiber hanging fillers is 50 mm, forming 8 groups of modular fillers, which are stacked inside the reactor to form a modular structure. The carbon fiber hanging fillers and the wire mesh frame are connected through an electrochemical workstation, and the carbon fiber fillers and the electrochemical workstation are connected by copper wires to form a closed circuit;

[0052] S2. Inoculate the hydrolytic acidification bacteria in the existing biological treatment system into the reactor, culture at a temperature of 28 °C and a pH value of 6.5, add glucose, NH 4 Cl and KH 2 PO 4 , keep C:N:P at 100:5:1, and culture and domesticate the microorganisms in a microcurrent environment. Set the initial current to 1 mA, gradually increase it by 0.08 mA every 2 days until the final current is 5 mA until a stable and highly active biofilm is formed on the carbon fiber hanging fillers;

[0053] S3. Input the wastewater to be treated into the reactor, control the influent flow rate to be 0.4 m 3 / h, keep the hydraulic retention time at 18 h, adjust the current to 3 mA through the electrochemical workstation, monitor the effluent results, and discharge after reaching the standard.

[0054] Example 2: A hydrolytic acidification wastewater treatment process for enhancing extracellular electron transfer, comprising the following steps:

[0055] S1. Construct a hydrolysis acidification reactor with dimensions of 2m×1m×2m. Use the carbon fiber hanging packing prepared in Preparation Example 2 as the anode and a wire mesh frame as the cathode. The carbon fiber hanging packing is connected in series as a whole by stainless steel wire ropes, with a spacing of 65mm between the upper and lower carbon fiber hanging packings, forming 8 groups of modular packings, which are stacked inside the reactor to form a modular structure. The carbon fiber hanging packing and the wire mesh frame are connected through an electrochemical workstation, and the carbon fiber packing and the electrochemical workstation are connected by copper wires to form a closed circuit;

[0056] S2. Inoculate the hydrolysis acidification bacteria from the existing biological treatment system into the reactor and culture it at a temperature of 30°C and a pH value of 7.0. Add glucose, NH 4 Cl and KH 2 PO 4 , maintain C:N:P at 100:5.2:1.1, and culture and domesticate the microorganisms in a micro-current environment. Set the initial current to 1mA and gradually increase it by 0.1mA every 2 days until the final current reaches 5.2mA, until a stable and highly active biofilm is formed on the carbon fiber hanging packing;

[0057] S3. Input the wastewater to be treated into the reactor, control the influent flow rate to be 0.5m 3 / h, maintain the hydraulic retention time at 21h, adjust the current to 5mA through the electrochemical workstation, monitor the effluent results, and discharge it after reaching the standard.

[0058] Example 3: A hydrolysis acidification wastewater treatment process for enhancing extracellular electron transfer, comprising the following steps:

[0059] S1. Construct a hydrolysis acidification reactor with dimensions of 2m×1m×2m. Use the carbon fiber hanging packing prepared in Preparation Example 3 as the anode and a wire mesh frame as the cathode. The carbon fiber hanging packing is connected in series as a whole by stainless steel wire ropes, with a spacing of 80mm between the upper and lower carbon fiber hanging packings, forming 6 groups of modular packings, which are stacked inside the reactor to form a modular structure. The carbon fiber hanging packing and the wire mesh frame are connected through an electrochemical workstation, and the carbon fiber packing and the electrochemical workstation are connected by copper wires to form a closed circuit;

[0060] S2. Inoculate the hydrolysis acidification bacteria from the existing biological treatment system into the reactor and culture it at a temperature of 32°C and a pH value of 7.5. Add glucose, NH 4 Cl and KH 2 PO 4 , maintain C:N:P at 100:5.5:1.2, and culture and domesticate the microorganisms in a micro-current environment. Set the initial current to 1mA and gradually increase it by 0.11mA every 2 days until the final current reaches 5.4mA, until a stable and highly active biofilm is formed on the carbon fiber hanging packing;

[0061] S3. Input the wastewater to be treated into the reactor, control the influent flow rate to be 0.6 m 3 / h, maintain the hydraulic retention time at 24 h, adjust the current to 7 mA through an electrochemical workstation, monitor the effluent result, and discharge it after reaching the standard.

[0062] Comparative Example 1: The difference between this comparative example and Preparation Example 1 is that 3-hexylthiophene is not added in step A1, and the remaining steps are the same as those in Preparation Example 1.

[0063] Comparative Example 2: The difference between this comparative example and Preparation Example 2 is that potassium metaphosphate is not added in step A2, and the remaining steps are the same as those in Preparation Example 2.

[0064] Comparative Example 3: The difference between this comparative example and Preparation Example 3 is that nano-titanium dioxide powder is not added in step A3, and the remaining steps are the same as those in Preparation Example 3.

[0065] Comparative Example 4: The difference between this comparative example and Example 1 is that the coating solution prepared in Comparative Example 1 is used, and the remaining steps are the same as those in Example 1.

[0066] Comparative Example 5: The difference between this comparative example and Example 2 is that the coating solution prepared in Comparative Example 2 is used, and the remaining steps are the same as those in Example 2.

[0067] Comparative Example 6: The difference between this comparative example and Example 3 is that the coating solution prepared in Comparative Example 3 is used, and the remaining steps are the same as those in Example 3.

[0068] Comparative Example 7: The difference between this comparative example and Example 1 is that biochar is used as the anode, and the remaining steps are the same as those in Example 1.

[0069] Comparative Example 8: The difference between this comparative example and Example 2 is that activated carbon fiber is used as the anode, and the remaining steps are the same as those in Example 2. The specific surface area of the activated carbon fiber (ACF) is 2000 m 2 / g, and the micropore volume accounts for more than 90% of the total pore volume.

[0070] An industrial wastewater sample from a coking plant was evenly divided into 8 portions, and the treatment processes of Examples 1 - 3 and Comparative Examples 4 - 8 were used for treatment respectively. The five-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), and ammonia nitrogen indexes in the effluent were monitored, and the COD removal rate and BOD5 removal rate of each example and comparative example were calculated. The results are shown in Tables 1 and 2:

[0071] Table 1. Wastewater treatment results of Examples 1 - 3 and Comparative Examples 4 - 8

[0072]

[0073] Table 2. COD removal rate and BOD5 removal rate results of Examples 1-3 and Comparative Examples 4-8

[0074]

[0075] According to the definition of the removal load per unit volume in GB / T 41017-2021 "Guidelines for Water Reuse - Evaluation Methods for Wastewater Reclamation Treatment Technologies and Processes", calculate the removal load per unit volume of BOD5, COD, and ammonia nitrogen (mg / m 3 ·h) of Examples 1-3 and Comparative Examples 4-8. The results are shown in Table 3:

[0076] Table 3. Removal load per unit volume results of Examples 1-3 and Comparative Examples 4-8

[0077]

[0078] It can be seen from Table 1, Table 2, and Table 3 that the removal rates of BOD5, COD, and ammonia nitrogen in Examples 1-3 are all higher than those in Comparative Examples 4-8, and the removal load per unit volume of Examples 1-3 is also higher than that of Comparative Examples 4-8. As the influent flow rate increases (from 0.4 m 3 / h - 0.6 m 3 / h), the BOD5 and COD removal rates of Examples 1-3 increase slightly, but the ammonia nitrogen removal rate remains relatively stable, and the removal load per unit volume also increases with the increase of the influent flow rate, indicating that at higher flow rates, the reactor can treat more pollutants.

[0079] In Comparative Example 4, 3-hexylthiophene was not added in step A1, which may affect the performance of the coating solution, and then affect the performance of the anode and the attachment of microorganisms. In Comparative Example 5, potassium metaphosphate was not added in step A2, and in Comparative Example 6, nano-titanium dioxide powder was not added in step A3, which may affect the formation and performance of the copolymer and the dispersibility and stability of the coating solution, and then affect the stability and conductivity of the anode.

[0080] In Comparative Examples 7 and 8, biochar and activated carbon fiber were used as anodes respectively. Compared with the carbon fiber hanging packing, they may have different conductivity, specific surface area, and microorganism attachment performance. The removal rates and removal loads per unit volume of Comparative Examples 7 and 8 are both lower than those of Examples 1 and 2, indicating that the carbon fiber hanging packing as an anode shows more excellent performance in wastewater treatment.

[0081] In Examples 1-3, as the current increases and the hydraulic retention time prolongs, both the removal rate and the removal load per unit volume increase. This may be because a higher current promotes the extracellular electron transfer and metabolic activities of microorganisms, while a longer hydraulic retention time allows microorganisms to have more sufficient time to degrade pollutants.

[0082] In summary, by controlling the feeding ratios of the raw materials during the preparation of the carbon fiber hanging packing and optimizing the parameters during wastewater treatment, the wastewater treatment methods of Examples 1-3 are significantly superior to those of Comparative Examples 4-8. This shows that the wastewater treatment method of the present invention can improve the overall efficiency of wastewater treatment.

[0083] In the description of the specification, the description referring to terms such as "embodiment", "each embodiment", etc. means that the specific features, structures, materials or characteristics described in connection with that embodiment or preparation example are included in at least one embodiment or preparation example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or preparation example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or preparation examples.

[0084] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A hydrolysis acidification wastewater treatment process for strengthening extracellular electron transfer, characterized in that: The following steps are involved: S1. Construct a hydrolysis acidification reactor, wherein the hydrolysis acidification reactor comprises a carbon fiber suspension filler arranged inside the reactor and a steel wire mesh frame floating on the water surface, wherein the carbon fiber suspension filler serves as an anode and the steel wire mesh frame serves as a cathode, wherein the carbon fiber suspension filler is connected in series by stainless steel wire ropes, and the carbon fiber suspension filler and the steel wire mesh frame are connected via an electrochemical workstation; S2, inoculating hydrolytic acidifying bacteria into the reactor, controlling the culture conditions, and taming the microorganisms in a microcurrent environment until a biofilm is formed on the carbon fiber suspension filler; S3, input the wastewater to be treated into the reactor, control the treatment conditions, monitor the effluent results, and discharge it after it meets the standards; The carbon fiber suspension filler in step S1 is prepared by the following steps: Select carbon fiber filaments with a diameter of 0.5-1.0 mm, wash the carbon fiber filaments, soak them in a hydrogen peroxide solution for activation, take them out and dry them to obtain pretreated carbon fiber filaments, immerse the pretreated carbon fiber filaments in a coating solution, keep them for 10-20 minutes, take out the carbon fiber filaments, gently absorb the excess coating solution with filter paper, hang them in an oven for drying for 2-4 hours until the coating layer is solidified, and after cooling, obtain a carbon fiber suspension filler; The coating solution is prepared by the following steps: A1. Add iodine and magnesium bars into the reactor, keep the reaction solution slightly boiling, add hexyl bromide dropwise, and after the addition is complete, continue to add anhydrous ethanol solution containing thiophene dropwise. After the addition is complete, react for 24 hours, separate the organic layer with saturated ammonium chloride solution, dry it with anhydrous sodium sulfate, and collect 3-hexylthiophene by distillation; A2, 3-hexylthiophene and potassium polymetaphosphate were added to a reactor pre-filled with toluene solvent, and stirred and dissolved under nitrogen protection until completely transparent, azobisisobutyronitrile and butylated hydroxyanisole were added, the reactor was sealed, and the reactor was placed in an oil bath, heated to 70-80°C, and reacted for 24-36h. After the reaction was completed, the mixture was cooled to room temperature, poured into methanol for precipitation, and filtered to obtain a copolymer precipitate; A3. Add the copolymer to N,N-dimethylformamide, stir until dissolved, add nano titanium dioxide powder, use ultrasonic disperser for 20-30 minutes to evenly disperse, stir for 1-2 hours under magnetic stirring, filter, wash, place in a 60°C vacuum oven to dry to constant weight, and re-formulate with N,N-dimethylformamide to a coating solution with a concentration of 40-50%.

2. A hydrolysis-acidification wastewater treatment process for enhancing extracellular electron transfer according to claim 1, characterized in that: The culture conditions in step S2 are as follows: temperature is 30±2°C, pH is 6.5-7.5, and C:N:P is maintained at 100:(5-5.5):(1-1.2).

3. The hydrolysis-acidification wastewater treatment process for enhancing extracellular electron transfer according to claim 1, characterized in that: The microcurrent environment in step S2 is specifically as follows: the initial current is 1 mA, which gradually increases by 0.08-0.12 mA every 2 days until the final current is 5-5.4 mA, and the total acclimation period is no less than 30 days.

4. The hydrolysis-acidification wastewater treatment process for enhancing extracellular electron transfer according to claim 1, characterized in that: The specific processing conditions in step S3 are: the water flow rate is 0.4-0.6m 3 / h, maintain the hydraulic retention time at 18-24h, and adjust the current to 3-7mA through the electrochemical workstation.

5. The hydrolysis-acidification wastewater treatment process for enhancing extracellular electron transfer according to claim 1, characterized in that: The concentration of the hydrogen peroxide solution is 0.1-0.3 mol / L, the activation temperature is 60-70° C., and the activation time is 1-2 h.

6. The hydrolysis-acidification wastewater treatment process for enhancing extracellular electron transfer according to claim 1, characterized in that: In step A1, the mass ratio of iodine, magnesium bar, hexyl bromide, thiophene and anhydrous ethanol is (0.2-0.3):(6.2-6.8):(50-52):(27.5-29):

200.

7. The hydrolysis-acidification wastewater treatment process for enhancing extracellular electron transfer according to claim 1, characterized in that: In step A2, the mass ratio of 3-hexylthiophene, potassium polymetaphosphate, toluene, azobisisobutyronitrile and butylated hydroxyanisole is (20-21.5):(12-14):100:(0.1-0.3):(0.05-0.07).

8. The hydrolysis-acidification wastewater treatment process for enhancing extracellular electron transfer according to claim 1, characterized in that: In step A3, the mass ratio of the copolymer, N,N-dimethylformamide and nano-titanium dioxide powder is (10-11):50:(2-2.5).

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