IPA waste liquid treatment method and treatment device coupled with electrocatalytic oxidation

Abstract

The invention relates to the technical field of industrial waste liquid treatment and resource recycling, in particular to an IPA waste liquid treatment method and device coupled with electrocatalytic oxidation. An IPA waste liquid treatment method coupled with electrocatalytic oxidation comprises the following steps: firstly, filtering suspended matters in waste liquid by using a filtering mechanism with a specific pore diameter, then carrying out two-stage electrocatalytic treatment, generating. OH by an anode in first-stage electrocatalysis for large-range degradation of pollutants, and generating. OH by the anode in second-stage electrocatalysis for degradation of small-molecular organic acids; then, a rectifying tower is used for carrying out rectification separation on the waste liquid subjected to electro-catalysis treatment, and distilled gas is separated by using a membrane module, so that recycled liquid with the IPA concentration being greater than 95% is produced at the tower top, and standard water with COD being smaller than or equal to 50 mg / L is discharged from a tower kettle, and the problems that in the prior art, separation and rectification are mainly used, so that the filtering efficiency is low, and the recycling rate is insufficient are solved.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment and resource recycling technology, and in particular to a method and apparatus for treating IPA wastewater coupled with electrocatalytic oxidation. Background Technology

[0002] IPA, as a low-toxicity and highly soluble solvent, is widely used in the electronics industry for photoresist stripping and the printing industry for ink dilution. During the manufacturing process, it generates IPA waste liquid with medium to high concentrations of recalcitrant organic matter (IPA concentration 1%-30%, COD 1000-8000mg / L), which needs to be treated before it can be discharged.

[0003] Existing technologies also exist for treating IPA solutions, but they often rely on membrane separation and distillation. However, due to the large amount of pollutants in the waste liquid, the distillation column is prone to caking and the membrane modules are easily contaminated, resulting in insufficient IPA recovery rate. Summary of the Invention

[0004] In view of this, the present invention provides a method for treating IPA waste liquid coupled with electrocatalytic oxidation to solve the problems of low filtration efficiency and insufficient recovery rate caused by separation and distillation as the main methods in the prior art; the present invention also provides an IPA waste liquid treatment device coupled with electrocatalytic oxidation to solve the above-mentioned technical problems.

[0005] A method for treating IPA wastewater using coupled electrocatalytic oxidation firstly involves filtering suspended solids from the wastewater using a filtration mechanism with a specific pore size, followed by two-stage electrocatalytic treatment. In the first-stage electrocatalysis, ·OH is generated at the anolyte, and in the second-stage electrocatalysis, ·OH is generated at the anolyte. Then, a distillation column is used to separate the waste liquid after electrocatalytic treatment, and a membrane module is used to separate the distilled gas to produce a recovery liquid with an IPA concentration greater than 95% at the top of the column, and qualified water with COD ≤ 50 mg / L is discharged from the bottom of the column.

[0006] Furthermore, before the two-stage electrocatalytic treatment, an acidic or alkaline solution is added to the waste liquid to adjust the pH of the waste liquid to 3-5.

[0007] Furthermore, during distillation separation, the pressure inside the distillation column is maintained at 0.05-0.08 MPa.

[0008] The beneficial effects of the IPA wastewater treatment method coupled with electrocatalytic oxidation in this invention are as follows: This method pre-treats the wastewater by first filtering it, reducing the total amount of pollutants in subsequent treatment; and facilitates pollutant treatment through two-stage electrocatalytic oxidation. Specifically, in the first-stage electrocatalysis, ·OH is generated at the anode, non-selectively degrading macromolecular organic matter; in the second-stage electrocatalysis, ·OH is generated at the anode... For the degradation of small-molecule organic acids, the waste liquid is first pre-treated with highly oxidizing ·OH to significantly reduce the total concentration of pollutants. Then, less oxidizing agents are used... The process is optimized to reduce energy consumption and is more targeted; it is processed through a distillation column, which facilitates separation and allows for the recovery of high-concentration recovery liquid from waste liquid for secondary recycling, as well as low-concentration compliant water. This solves the problem of low filtration efficiency and insufficient recovery rate caused by separation and distillation as the main methods in existing technologies.

[0009] Furthermore, generating negative pressure within the column during distillation facilitates the reduction of the azeotropic temperature between IPA and water, thereby lowering separation energy consumption.

[0010] Furthermore, by adjusting the solution to acidic conditions before electrocatalytic oxidation, the generation efficiency of ·OH can be maximized.

[0011] An IPA wastewater treatment device coupled with electrocatalytic oxidation includes a filtration mechanism, an electrocatalytic treatment mechanism, and a distillation column arranged in series. The filtration mechanism is capable of filtering suspended solids of a specific size. The electrocatalytic treatment mechanism includes a primary electrocatalytic mechanism and a secondary electrocatalytic mechanism, wherein ·OH is generated at the anode in the primary electrocatalysis and ·OH is generated at the anode in the secondary electrocatalysis. The distillation column is also equipped with a membrane module for filtering the steam, so that the top of the column produces a recovery liquid with an IPA concentration greater than 95%, and the bottom of the column discharges compliant water with COD ≤ 50 mg / L.

[0012] Furthermore, in the primary electrocatalysis, the anode is a titanium-based lead dioxide-graphene composite electrode, and the cathode is stainless steel; in the secondary electrocatalysis, the anode is a ruthenium-iridium (Ru-Ir) coated titanium electrode, and the cathode is a modified mesoporous silica adsorption packing layer.

[0013] Furthermore, the device also includes an acidic liquid storage tank and an alkaline liquid storage tank, as well as a variable frequency dosing pump for controlling the opening and closing of the aforementioned storage tanks. The device also includes an acid-base sensor for checking the acidity or alkalinity of the solution to maintain the acidity or alkalinity of the waste liquid.

[0014] Furthermore, the distillation column is equipped with a polydimethylsiloxane-ceramic composite membrane for separating gaseous substances, and an IPA storage tank for storing the separated IPA solution is connected to the distillation column.

[0015] Furthermore, the filtration mechanism, the electrocatalytic treatment mechanism, and the distillation column are all equipped with COD sensors to detect COD concentration, and on / off valves that control the connection between the filtration mechanism and the electrocatalytic treatment mechanism, and between the electrocatalytic treatment mechanism and the distillation column, based on the detection results of the COD sensors.

[0016] Furthermore, the modified mesoporous silica adsorbent packing layer has two sets arranged in parallel, with a high-temperature hot air generator and a regeneration storage tank located below each set.

[0017] Furthermore, the device also includes a buffer tank for containing waste liquid from the reaction.

[0018] The beneficial effects of the IPA wastewater treatment device coupled with electrocatalytic oxidation in this invention are as follows: The filtration mechanism, electrocatalytic treatment mechanism, and distillation column arranged in series facilitate sequential filtration, electrocatalytic oxidation, and distillation separation of the wastewater; the initial filtration significantly reduces suspended solids in the wastewater, preventing interference with the oxidant generated during subsequent electrocatalytic oxidation; the two-stage electrocatalytic treatment facilitates the treatment of pollutants. Specifically, in the first-stage electrocatalysis, ·OH is generated at the anode, non-selectively degrading large organic molecules; in the second-stage electrocatalysis, ·OH is generated at the anode... For the degradation of small-molecule organic acids, the waste liquid is first pre-treated with highly oxidizing ·OH to significantly reduce the total concentration of pollutants. Then, less oxidizing agents are used... The process is optimized to reduce energy consumption and is more targeted; it is processed through a distillation column, which facilitates separation and allows for the recovery of high-concentration recovery liquid from waste liquid for secondary recycling, as well as low-concentration compliant water. This solves the problem of low filtration efficiency and insufficient recovery rate caused by separation and distillation as the main methods in existing technologies.

[0019] Furthermore, by setting the anode as a titanium-based lead dioxide-graphene composite electrode in the primary electrocatalysis to facilitate the generation of ·OH at the anode, and setting the anode as a ruthenium-iridium coated titanium electrode in the secondary electrocatalysis, and the cathode as a modified mesoporous silica adsorption packing layer, it is possible to facilitate the generation of ·OH at the anode. On the other hand, it enables the cathode to have an adsorption effect.

[0020] Furthermore, by using a variable frequency dosing pump to maintain the pH of the pretreatment solution, the generation efficiency of ·OH can be improved during the electrocatalytic oxidation process.

[0021] Furthermore, the polydimethylsiloxane-ceramic composite membrane facilitates the purification of IPA in waste liquid, making it easy to reuse.

[0022] Furthermore, by setting up COD sensors, it is ensured that the reaction at each stage is complete before flowing to the next stage.

[0023] Furthermore, by setting up a bypass, the continuous processing capability is improved, so that when the adsorption capacity of one path is limited, the adsorption can be switched to another path, thereby alternating operation and increasing the continuous processing time.

[0024] Furthermore, the buffer tank design helps prevent sudden changes in pressure and liquid levels within the pipeline. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the IPA waste liquid treatment device coupled with electrocatalytic oxidation in this invention; Figure 2 This is a schematic diagram of the process for treating IPA waste liquid by coupled electrocatalytic oxidation in this invention.

[0027] The labels in the diagram represent: 1. Pretreatment unit; 2. Staged treatment unit; 3. Distillation column; 4. Solenoid valve; 5. IPA storage tank; 6. Regeneration unit. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0029] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0030] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms and should not be construed as indicating or implying relative importance. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0031] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0033] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0034] To better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings.

[0035] In Example 1 of the IPA wastewater treatment device coupled with electrocatalytic oxidation in this invention (hereinafter referred to as the wastewater treatment device): In this embodiment, the waste liquid treatment device includes a filtration mechanism, an electrocatalytic treatment mechanism, and a distillation column arranged in series. Each stage of treatment has its own liquid holding space. After each stage of treatment is completed, the treated waste liquid is discharged to the next mechanism for further treatment, and so on.

[0036] The filtration mechanism is pre-installed within pretreatment unit 1, employing a polypropylene pleated filter element with a filtration accuracy of 5-10 μm and a throughput of 15-20 L / (m²·min). It traps suspended solids such as photoresist residue and ink particles in the waste liquid (suspended solids ≤5 mg / L after treatment). Filtration reduces the suspended solids content, preventing them from covering the active sites of the electrocatalytic electrode (resulting in a reduction of ·OH production of over 30%), thus facilitating the electrocatalytic oxidation reaction. During the electrocatalytic oxidation reaction, pollutants are primarily treated by generating an oxidant at the anode. In this embodiment, ·OH and ·OH are generated within the electrocatalytic treatment mechanism. In order to better generate this type of oxidant, the pH of the solution needs to be adjusted.

[0037] Based on data analysis, when pH > 6 A decrease in concentration reduces ·OH production by 40%; a pH < 2 accelerates the cathode hydrogen evolution reaction, wasting electrical energy; therefore, the optimal reaction environment is pH 3-5. To achieve this, a structure for adjusting the pH of the waste liquid is also included in the filtration mechanism. The device also includes acidic and alkaline liquid storage tanks. The acidic liquid storage tank contains 0.5 mol / L dilute sulfuric acid; the alkaline liquid storage tank contains 0.5 mol / L sodium hydroxide. The device also includes a pH sensor and a variable frequency dosing pump to check the pH of the solution. The pH sensor detects the solution in the filtration mechanism; if the acidity is too strong, alkaline liquid is added to the waste liquid via the dosing pump to neutralize it. If the pH is insufficiently alkaline or acidic, acidic liquid is added to the waste liquid via the dosing pump.

[0038] Meanwhile, during the waste liquid treatment process, since the waste liquid flows within the device, directly discharging the filtered large amount of liquid into subsequent mechanisms would cause fluctuations in flow rate or pressure. Therefore, a buffer tank with an effective volume of 1-2 m³ is also installed inside the filtration mechanism to eliminate feed flow rate fluctuations within ±5% and avoid COD (chemical oxygen demand) removal rate fluctuations of ±10% caused by unstable electrode contact time, thus ensuring consistent treatment.

[0039] Following this, electrocatalytic oxidation is required. Since only filtration is performed within the filtration unit, the solution still contains a significant amount of contaminants. Therefore, a "two-stage electrocatalytic oxidation + adsorption coupling" design is adopted to achieve a stepwise degradation of organic matter. Specifically, a staged treatment unit 2 is set up, where two-stage catalytic oxidation is achieved. In the first-stage catalysis, the anode is a titanium-based lead dioxide-graphene composite electrode, and the cathode is a stainless steel electrode. In this embodiment, the electrode spacing is 5-8 mm, and the effective reaction area is 1-2 m². Operating parameters are: voltage 1.8-2.5 V, current density 20-30 mA / cm², and reaction time 60-90 min. The ·OH generated at the anode (oxidation potential 2.8 V) non-selectively degrades 60%-70% of macromolecular organic matter (such as benzene compounds and long-chain esters), reducing COD to below 1000 mg / L. In the second-stage catalysis, the anode is a ruthenium-iridium (Ru-Ir) coated titanium electrode, and the cathode is a modified mesoporous silica adsorption packing layer. Operating parameters: voltage 1.5-2.0V, reaction time 40-60min. The adsorption packing material is prepared by "3-aminopropyltriethoxysilane modification + hydroxylation treatment", with a specific surface area ≥800m² / g, pore size 2-5nm, and saturated adsorption capacity for organic matter ≥0.4g / g. In the secondary electrocatalysis, the ruthenium-iridium electrode generates... (Oxidation potential 1.8V) It degrades small molecule organic acids, and the adsorption packing retains residual organic matter and regenerates it in situ through oxidation, ultimately achieving a COD ≤ 50 mg / L, realizing simultaneous "adsorption-degradation-regeneration". It is worth noting that a COD sensor (ultraviolet absorption method, range 0-5000 mg / L, accuracy ±5%) is also installed to monitor the COD value, ensuring that the wastewater treated by electrocatalytic oxidation meets the requirements.

[0040] After two stages of catalysis in the electrocatalytic treatment unit, the pollutant content is significantly reduced. IPA is costly and present in large quantities in solution, therefore, it needs to be separated and processed separately for easy reuse. In this embodiment, a floating valve distillation column 3 is used, with a diameter of 0.5-1m and 20-30 trays. Operating parameters are: pressure 0.05-0.08MPa, reboiler temperature 65-75℃, and reflux ratio 1.5-2.0. By maintaining a negative pressure environment within the distillation column 3 during distillation, the azeotropic temperature is lowered, reducing heating energy consumption. The negative pressure reduces the IPA-water azeotropic temperature from 80.3℃ (at atmospheric pressure) to 65-75℃, reducing heating energy consumption by 35%-45%. The 20-30 floating valve trays provide sufficient gas-liquid contact, and the 1.5-2.0 reflux ratio balances purity and energy consumption, resulting in a crude IPA concentration of 95%-98% at the top of the column. Through gas-liquid contact separation, 95%-98% crude IPA is produced at the top of the column, and qualified water (COD≤50mg / L) is discharged from the bottom of the column. The crude IPA at the top of the column is further processed using a PDMS (polydimethylsiloxane)-ceramic composite membrane (membrane area 5-10m²) for filtration. Operating parameters are: temperature 40-50℃, pressure difference across the membrane 0.02-0.03MPa, flux ≥1.5kg / (m²·h). The hydrophobic silica chains (-Si-O-Si-) of the PDMS active layer have high selectivity for IPA (permeability coefficient is 10-15 times that of water). Driven by a temperature of 40-50℃ and a pressure difference of 0.02-0.03MPa, IPA preferentially permeates through the membrane layer, and the purity after condensation is ≥99.8%. Recirculation of the retained water increases the recovery rate to ≥90%. After selective permeation, IPA with a purity of 99.8% is obtained. The retained water is recycled back to distillation column 3 for reuse, improving the recovery rate. In this embodiment, an IPA concentration sensor is also used to monitor the IPA concentration in real time, ensuring that the IPA concentration at the top of the column and the bottom of the vessel meets the requirements for further processing. The qualified IPA solution enters the IPA storage tank 5 for subsequent use.

[0041] Furthermore, since the initial concentration of the waste liquid has a significant impact on subsequent treatment processes, this embodiment also includes a PID algorithm control module. This module contains a pre-built LSTM model based on historical data, which controls the reaction time or start / stop based on parameter information detected by various sensors. For example, if the initial COD in the waste liquid is >5000 mg / L, the first-stage reaction time is extended to 90 minutes. Membrane flux sensors or pressure sensors can also be installed in the filter assembly or distillation column to determine if the membrane module needs cleaning when insufficient membrane flux or excessive pressure is detected.

[0042] In this embodiment, two sets of modified mesoporous silica adsorption packing layers are provided, connected in parallel. An electromagnetic valve 4 is also provided to switch one of the two modified mesoporous silica adsorption packing layers into the device. A regeneration unit 6 is connected to the electromagnetic valve. The regeneration unit 6 contains a high-temperature hot air generator and a regeneration storage tank containing sodium hydroxide solution. When treating waste liquid, if the adsorption capacity of the modified mesoporous silica adsorption packing layer is insufficient as the adsorption amount increases, the electromagnetic valve 4 selects to connect the other set of modified mesoporous silica adsorption packing layers into the device. Then, the high-temperature hot air generator and regeneration storage tank corresponding to the saturated modified mesoporous silica adsorption packing layer are used to clean and regenerate the saturated modified mesoporous silica adsorption packing layer for subsequent recycling. This ensures the reusability of the modified mesoporous silica adsorption packing layer without affecting the waste liquid treatment effect.

[0043] Specifically, during operation, the device feeds IPA waste liquid through a feed pump into a filtration system, where suspended solids are removed before it enters a buffer tank. A pH sensor detects the pH of the waste liquid, and the PLC controller activates a variable frequency dosing pump to add dilute sulfuric acid or sodium hydroxide, adjusting the pH to 3-5. Only after this treatment can the electrocatalytic oxidation process proceed. The pretreated waste liquid is then passed through a primary module and reacted for 60-90 minutes at a voltage of 1.8-2.5V and a current density of 20-30mA / cm². When COD ≤ 1000mg / L, it enters the secondary module. In the secondary module, the waste liquid reacts for 40-60 minutes at a voltage of 1.5-2.0V. When COD ≤ 50mg / L, it enters the intelligent recovery unit. The adsorption capacity of the secondary module has an upper limit. If COD > 50mg / L, the system switches to a regeneration bypass, where the packing material is cleaned with hot air and regenerant. After regeneration, the waste liquid returns to the main process.

[0044] Subsequently, the waste liquid after electrocatalytic oxidation enters the distillation column, where it is distilled at 0.05-0.08 MPa and 65-75℃. 95%-98% crude IPA is produced at the top of the column, and the treated water in the bottom is discharged or reused. The crude IPA enters the membrane module, where it is separated at 40-50℃ and a pressure difference of 0.02-0.03 MPa. IPA with a purity ≥99.8% enters the product storage tank, and the retained water is returned to the distillation column. If the IPA purity is <99.8%, the PLC controller increases the pressure difference across the membrane by 0.005-0.01 MPa to ensure the purity meets the standard.

[0045] Meanwhile, during the production control process, PID algorithms are used to control the pH, temperature, and gas pressure, making the control more stable. At the same time, the reaction time and reflux ratio are adjusted based on the initial concentration of waste liquid. For example, when IPA > 20%, the distillation reflux ratio is increased to 2.0.

[0046] In Example 1 of the IPA wastewater treatment method coupled with electrocatalytic oxidation in this invention (hereinafter referred to as the wastewater treatment method): The IPA waste liquid treatment method coupled with electrocatalytic oxidation in this invention is consistent with the usage method in the above-mentioned waste liquid treatment device, and will not be repeated here.

[0047] Taking the treatment of photoresist IPA waste liquid from the semiconductor industry (initial parameters: IPA concentration 12%, COD 3200mg / L, suspended solids 80mg / L, pH 6.8, treatment capacity 1m³ / h) as an example, the complete working process is as follows: 1. Feed preparation (0-5 min): Input waste liquid parameters, LSTM model generates initial scheme (pH 4.2, first stage voltage 2.2V, distillation pressure 0.06MPa), start feed pump after system self-check shows no abnormalities.

[0048] 2. Pretreatment (5-35 min): Filtration with an 8μm filter cartridge (20 min, suspended solids 4 mg / L), pH adjusted to 4.2 with acid (15 min), and the liquid enters the graded purification unit after the buffer tank level reaches 80%.

[0049] 3. Staged purification (35-185 min): First-stage electrocatalysis (35-110 min): 2.2V voltage, 25mA / cm² current density, COD 1050mg / L at 75 min (exceeding the standard), automatically extended to 110 min, COD decreased to 980mg / L; Secondary electrocatalytic adsorption (110-185 min): React at 1.8V for 50 min, COD drops to 42 mg / L, and enters the recovery unit.

[0050] 4. Intelligent recycling (185-335 min): Negative pressure distillation (185-285 min): 0.06 MPa, 70℃, reflux ratio 1.8, crude product concentration was 96.2% at 235 min (low); after adjusting the reflux ratio to 1.9, the concentration was 97.5% at 285 min. Membrane separation (285-335 min): at 45℃ and 0.025 MPa, the purity was 99.7% (low) at 315 min. When the pressure difference was increased to 0.028 MPa, the purity was 99.85% at 335 min, and the recovery rate was 92%.

[0051] 5. Adsorption regeneration (335-395 min): Switch to the regeneration bypass, perform 120℃ hot air cleaning for 20 min, 0.5% NaOH cleaning for 30 min, and hot air drying for 10 min. The packing regeneration rate is 86%.

[0052] 6. Shutdown and Archiving (395-400 min): Turn off the equipment, flush the pipes with clean water for 5 min, automatically archive the data (energy consumption 420 kWh / ton, COD removal rate 98.7%), generate a PDF report, and the system will be in standby mode.

[0053] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for treating IPA waste liquid coupled with electrocatalytic oxidation, characterized in that: First, a filtration system with a specific pore size is used to filter suspended solids in the waste liquid. Then, a two-stage electrocatalytic treatment is performed: in the first-stage electrocatalysis, ·OH is generated at the anode, and in the second-stage electrocatalysis, ·OH is generated at the anode. Then, a distillation column is used to separate the waste liquid after electrocatalytic treatment, and a membrane module is used to separate the distilled gas to produce a recovery liquid with an IPA concentration greater than 95% at the top of the column, and qualified water with COD ≤ 50 mg / L is discharged from the bottom of the column.

2. The method for treating IPA waste liquid by coupled electrocatalytic oxidation according to claim 1, characterized in that: Before performing two-stage electrocatalytic treatment, an acidic or alkaline solution is added to the waste liquid to adjust its pH to 3-5.

3. The method for treating IPA waste liquid by coupled electrocatalytic oxidation according to claim 1 or 2, characterized in that: During distillation separation, the pressure inside the distillation column should be maintained at 0.05-0.08 MPa.

4. A device for treating IPA waste liquid coupled with electrocatalytic oxidation, characterized in that: The system includes a filtration mechanism, an electrocatalytic treatment mechanism, and a distillation column arranged in series. The filtration mechanism can filter suspended solids of a specific size. The electrocatalytic treatment mechanism includes a primary electrocatalytic mechanism and a secondary electrocatalytic mechanism, wherein ·OH is generated at the anode in the primary electrocatalysis and ·OH is generated at the anode in the secondary electrocatalysis. The distillation column is also equipped with a membrane module for filtering the steam, so that the top of the column produces a recovery liquid with an IPA concentration greater than 95%, and the bottom of the column discharges compliant water with COD ≤ 50 mg / L.

5. The IPA wastewater treatment device coupled with electrocatalytic oxidation according to claim 4, characterized in that: In the primary electrocatalysis, the anode is a titanium-based lead dioxide-graphene composite electrode, and the cathode is stainless steel; in the secondary electrocatalysis, the anode is a ruthenium-iridium coated titanium electrode, and the cathode is a modified mesoporous silica adsorption packing layer.

6. The IPA wastewater treatment device coupled with electrocatalytic oxidation according to claim 5, characterized in that: The device also includes an acidic liquid storage tank and an alkaline liquid storage tank, as well as a variable frequency dosing pump for controlling the opening and closing of the aforementioned storage tanks. The device also includes an acid-base sensor for checking the acidity or alkalinity of the solution to maintain the acidity or alkalinity of the waste liquid.

7. The IPA wastewater treatment device coupled with electrocatalytic oxidation according to any one of claims 4-6, characterized in that: The distillation column is equipped with a polydimethylsiloxane-ceramic composite membrane for separating gaseous substances, and an IPA storage tank is connected to the distillation column for storing the separated IPA solution.

8. The IPA wastewater treatment device coupled with electrocatalytic oxidation according to any one of claims 4-6, characterized in that: The filtration mechanism, electrocatalytic treatment mechanism, and distillation column are all equipped with COD sensors to detect COD concentration, and on / off valves that control the connection between the filtration mechanism and the electrocatalytic treatment mechanism, and between the electrocatalytic treatment mechanism and the distillation column, based on the detection results of the COD sensors.

9. The IPA wastewater treatment device coupled with electrocatalytic oxidation according to claim 5 or 6, characterized in that: The modified mesoporous silica adsorbent packing layer has two sets arranged in parallel, with a high-temperature hot air generator and a regeneration storage tank below each set.

10. The IPA wastewater treatment device coupled with electrocatalytic oxidation according to any one of claims 4-6, characterized in that: The device also includes a buffer tank for holding waste liquid from the reaction.

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