Organic photoresist component on-line electrochemical degradation and alkalinity maintenance device

Abstract

The present application relates to the technical field of organic photoresist wastewater treatment, and particularly relates to an on-line electrochemical degradation and alkalinity maintaining device for organic photoresist components, which comprises a pretreatment unit, an on-line electrochemical degradation unit, a dynamic alkalinity maintaining unit, a product separation unit and a PLC control system, and each unit is sequentially connected through a corrosion-resistant pipeline; the pretreatment unit is used for removing solid particles, suspended impurities, macromolecular organic matters and part of additives in the wastewater; the on-line electrochemical degradation unit adopts a bipolar electrolytic cell structure, and is internally provided with a titanium-based ruthenium-iridium coating anode and a graphite cathode, and is used for electrochemical oxidation degradation of the organic photoresist components; the dynamic alkalinity maintaining unit adopts a sodium hydroxide-sodium carbonate compound lye, and combines on-line pH monitoring and PLC linkage adjustment to stably maintain the pH value of the wastewater at 8.5-10.5; and the product separation unit is used for separating degradation products, precipitates and trace impurities.

Description

Technical Field

[0001] This invention relates to the field of organic photoresist wastewater treatment technology, and in particular to an online electrochemical degradation and alkalinity maintenance device for organic photoresist components. Background Technology

[0002] In high-end manufacturing fields such as semiconductor chips and flexible display panels, photolithography is the core technology for achieving fine patterning. Organic photoresist, as a key material in photolithography, mainly consists of photoinitiators, crosslinking monomers, organic semiconductors, resins, and various additives. It is characterized by structural stability, poor biodegradability, and high toxicity. The photolithography process generates a large amount of wastewater containing organic photoresist. If this wastewater is discharged directly, it will not only seriously pollute water bodies and soil environments but also waste resources. If it is reused directly, the residual organic photoresist in the wastewater will affect the stability of subsequent production processes, leading to a decrease in product yield.

[0003] In existing technologies, methods for treating organic photoresist components mainly include physical adsorption, chemical oxidation, biodegradation, and electrochemical degradation. Among these, electrochemical degradation has become a research hotspot due to its advantages such as high reaction efficiency, no secondary pollution, and the ability to process continuously online. However, existing electrochemical degradation devices and processes still have many shortcomings: On the one hand, organic photoresist has a complex structure, and conventional electrochemical devices have low degradation efficiency, making it difficult to completely mineralize it. After degradation, a large number of intermediate products remain, which cannot meet emission standards.

[0004] On the other hand, the electrochemical degradation process generates acidic substances, which cause the pH value of the wastewater to drop continuously, destroying the stability of the reaction system. This not only reduces the catalytic activity of the electrode and shortens its service life, but also inhibits the degradation reaction of organic photoresist and even produces toxic byproducts.

[0005] Meanwhile, existing devices do not achieve synergistic linkage between alkalinity maintenance and electrochemical degradation. Most rely on manual intermittent addition of alkali solution to adjust pH, which results in problems such as adjustment lag, large alkalinity fluctuations, and serious waste of reagents, making them unsuitable for online continuous treatment requirements. In some devices, pretreatment is insufficient, and solid particles and suspended impurities in the wastewater can easily cause electrode blockage and wear, affecting the long-term stable operation of the device. At the same time, it is difficult to adapt to organic photoresist wastewater with different components and concentrations.

[0006] Furthermore, in existing technologies, organic photoresist degradation and alkalinity adjustment are mostly independent units, not integrated into a single design. This results in large equipment footprint, cumbersome operation, high operating costs, and an inability to achieve precise and coordinated control of process parameters.

[0007] Therefore, there is a need for a device that integrates online electrochemical degradation, dynamic alkalinity maintenance, efficient pretreatment, and product separation to solve the problems of low degradation efficiency, unstable alkalinity, easy electrode wear, and inability to operate continuously in existing devices. Summary of the Invention

[0008] In view of this, the purpose of this invention is to propose an online electrochemical degradation and alkalinity maintenance device for organic photoresist components, so as to solve the problems of incomplete degradation of organic photoresist, large alkalinity fluctuations, easy electrode wear, high operating costs, and inability to perform continuous online treatment in existing organic photoresist wastewater treatment devices.

[0009] Based on the above objectives, the present invention provides an online electrochemical degradation and alkalinity maintenance device for organic photoresist components, comprising: a pretreatment unit, wherein the pretreatment unit is used to remove solid particles, suspended impurities, macromolecular organic matter and some additives from organic photoresist wastewater; An online electrochemical degradation unit is connected to the pretreatment unit. The online electrochemical degradation unit adopts a bipolar electrolytic cell structure and has a built-in catalytic electrode assembly for electrochemical oxidation degradation of pretreated organic photoresist wastewater. A dynamic alkalinity maintenance unit is connected to the online electrochemical degradation unit. The dynamic alkalinity maintenance unit uses a sodium hydroxide-sodium carbonate compound alkaline solution and combines online pH monitoring with PLC linkage adjustment to adjust the alkalinity of the wastewater after electrochemical degradation. The product separation unit is connected to the dynamic alkalinity maintenance unit and is used to separate degradation products, precipitates and unreacted trace impurities from the wastewater after electrochemical degradation. The PLC control system is electrically connected to the pretreatment unit, the online electrochemical degradation unit, the dynamic alkalinity maintenance unit, and the product separation unit, and is used to collect the operating parameters of each unit and adjust the operating status of the relevant equipment. The pretreatment unit, the online electrochemical degradation unit, the dynamic alkalinity maintenance unit, and the product separation unit are connected in sequence via corrosion-resistant pipes.

[0010] Preferably, the pretreatment unit includes a bar screen filter, a precision filter assembly, an ultrasonic demulsifier, and a buffer regulating tank connected in sequence. The bar screen filter is used to remove solid particles, photoresist residue, and suspended impurities from the wastewater. The precision filter assembly is used to remove fine suspended particles, colloidal impurities, large molecular organic matter, and undissolved photoresist particles. The ultrasonic demulsifier is used to break down the emulsion in the wastewater and release small organic photoresist molecules encapsulated in the emulsion. The buffer regulating tank is used to stabilize the wastewater flow rate and composition.

[0011] Preferably, the bar filter adopts a stainless steel bar structure with a bar spacing of 0.5-1.0 mm; the precision filter assembly is a two-stage filtration structure, the first stage is a polypropylene microfiltration membrane filter with a pore size of 0.45 μm, and the second stage is a polytetrafluoroethylene ultrafiltration membrane filter with a pore size of 0.22 μm; the ultrasonic demulsifier has an ultrasonic frequency of 20-40 kHz, a power of 300-500 W, and an action time of 5-10 min; the buffer regulating tank has a built-in stirring device with a stirring speed of 200-300 r / min, and is used to initially adjust the pH value of the wastewater to 7.0-8.0.

[0012] Preferably, the online electrochemical degradation unit includes an electrolytic cell body, a catalytic electrode assembly, an aeration device, a heating device, and an electrode cleaning assembly. The electrolytic cell body is made of 316L stainless steel, and a partition is provided inside the electrolytic cell body to divide the electrolytic cell body into an anode area and a cathode area.

[0013] Preferably, the partition is an ion exchange membrane, the catalytic electrode assembly adopts an alternating anode-cathode arrangement structure, the anode is a titanium-based ruthenium-iridium coated electrode, the cathode is a graphite electrode, the electrode spacing is 5-10 mm, and flow sensors are respectively installed at the inlet and outlet of the electrolytic cell body.

[0014] Preferably, the aeration device is located at the bottom of the electrolytic cell body and uses a microporous aeration head, with an aeration rate of 0.5-1.0 m³ / (m²·h); the heating device uses an electric heating tube and is located on the side wall of the electrolytic cell body, and the heating device is linked with a temperature sensor to control the wastewater temperature in the electrolytic cell body at 30-40℃; the electrode cleaning assembly is an online spray cleaning structure and is located on both sides of the electrode.

[0015] Preferably, the dynamic alkalinity maintenance unit includes an alkaline solution storage tank, a metering pump, a static mixer, an online pH monitor, and a reflux adjustment component. The alkaline solution storage tank is made of corrosion-resistant PE material. The mass ratio of sodium hydroxide to sodium carbonate in the sodium hydroxide-sodium carbonate compound alkaline solution is 2:1. The metering pump is linked to the online pH monitor to automatically adjust the flow rate of the metering pump according to the real-time changes in the pH value of the wastewater.

[0016] Preferably, the static mixer is located between the outlet of the electrolytic cell and the alkali addition port, and the static mixer has multiple layers of staggered guide vanes inside, with a mixing time of 3-5 minutes; the pH online monitoring instrument is located at the outlet of the static mixer, with a monitoring accuracy of ±0.1, and is used to control the pH value of the wastewater between 8.5 and 10.5; the reflux adjustment component includes a reflux pipe and a reflux pump, which is used to reflux wastewater with an unqualified pH value after adjustment back to the static mixer for readjustment, with a reflux ratio of 1:5-1:10.

[0017] Preferably, the product separation unit includes a sedimentation tank, a filter press, an ultrafiltration device, and a clear water storage tank. The sedimentation tank has a built-in stirring device with a stirring speed of 150-200 r / min and a residence time of 10-15 min. The filter press is a plate and frame filter press, and the filtrate after filtration is returned to the pretreatment unit. The ultrafiltration device uses a hollow fiber ultrafiltration membrane with a pore size of 0.01 μm. The clear water storage tank is made of 316L stainless steel and has a built-in liquid level sensor.

[0018] Preferably, the PLC control system is used to collect temperature, pressure, liquid level, flow rate, pH value, electrode voltage and electrode current parameters in real time, and automatically adjust the power of the ultrasonic demulsifier, the temperature of the electrolytic cell, the electrode voltage, the electrode current, the flow rate of the metering pump and the aeration rate through a preset program. The PLC control system is also equipped with a manual control mode and a data acquisition and storage module.

[0019] The beneficial effects of this invention are: 1. This online electrochemical degradation and alkalinity maintenance device for organic photoresist components, by setting up a pretreatment unit in conjunction with an online electrochemical degradation unit, can remove solid particles, suspended impurities, macromolecular organic matter and some additives before the wastewater enters the electrolytic cell, reducing electrode clogging and wear; at the same time, by using a titanium-based ruthenium-iridium coated anode and a graphite cathode in conjunction with aeration and stirring, the organic photoresist components are in full contact with the electrodes, improving the degradation efficiency of the organic photoresist components.

[0020] 2. This online electrochemical degradation and alkalinity maintenance device for organic photoresist components, by setting up a dynamic alkalinity maintenance unit, combines sodium hydroxide-sodium carbonate compound alkaline solution, an online pH monitor, a metering pump, a static mixer, and a reflux adjustment component. It can adjust the amount of alkaline solution added in real time according to the changes in the pH value of the wastewater, and maintain the pH value of the wastewater stably at 8.5-10.5, avoiding the accumulation of acidic substances that cause electrode passivation and a decrease in reaction efficiency.

[0021] 3. This online electrochemical degradation and alkalinity maintenance device for organic photoresist components, by setting up a product separation unit, can separate the degradation precipitate, sludge, trace suspended impurities and degradation intermediate products. The filtrate after pressure filtration is returned to the pretreatment unit, and the purified wastewater can be reused or discharged in compliance with standards, thereby improving wastewater treatment efficiency.

[0022] 4. This online electrochemical degradation and alkalinity maintenance device for organic photoresist components, through the installation of a PLC control system, can collect parameters such as temperature, pressure, liquid level, flow rate, pH value, electrode voltage and current in real time, and adjust parameters such as ultrasonic demulsifier power, electrolytic cell temperature, electrode voltage and current, metering pump flow rate, and aeration rate to achieve continuous online operation of pretreatment, electrochemical degradation, alkalinity maintenance and product separation, reducing manual intervention. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall system flow of the present invention; Figure 2 This is a schematic diagram of the preprocessing unit structure of the present invention; Figure 3 This is a schematic diagram of the overall system flow and PLC linkage control of the present invention; Figure 4 This is a schematic diagram of the online electrochemical degradation unit structure of the present invention; Figure 5 This is a schematic diagram of the dynamic alkalinity maintenance and PLC linkage adjustment process of the present invention; Figure 6 This is a schematic diagram of the product separation unit structure of the present invention.

[0025] Explanation of reference numerals in the attached figures: 1. Pretreatment unit; 11. Grille filter; 12. Precision filter assembly; 121. Polypropylene microfiltration membrane filter; 122. Polytetrafluoroethylene ultrafiltration membrane filter; 13. Ultrasonic demulsifier; 14. Buffer tank; 2. Online electrochemical degradation unit; 21. Electrolyte body; 22. Catalytic electrode assembly; 221. Titanium-based ruthenium-iridium coated electrode; 222. Graphite electrode; 23. Aeration device; 24. Heating device; 25. Electrode cleaning assembly; 26. Ion exchange membrane; 3. Dynamic alkalinity maintenance unit; 31. Alkali storage tank; 32. Metering pump; 33. Static mixer; 34. Online pH monitor; 35. Reflux control assembly; 4. Product separation unit; 41. Sedimentation tank; 42. Filter press; 43. Ultrafiltration unit; 44. Clear water storage tank; 5. PLC control system. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0027] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] like Figures 1 to 6 As shown, an online electrochemical degradation and alkalinity maintenance device for organic photoresist components includes a pretreatment unit 1, an online electrochemical degradation unit 2, a dynamic alkalinity maintenance unit 3, a product separation unit 4, and a PLC control system 5. Each unit is connected in sequence through corrosion-resistant pipes.

[0029] Organic photoresist wastewater first enters pretreatment unit 1, where solid particles, suspended impurities, macromolecular organic matter, and some additives are removed. Then, it enters online electrochemical degradation unit 2, where the organic photoresist components in the wastewater undergo electrochemical oxidation degradation. The degraded wastewater then enters dynamic alkalinity maintenance unit 3, which automatically adds compound alkaline solution based on online pH monitoring results and readjusts the pH of wastewater with unacceptable values ​​via reflux adjustment component 35. After alkalinity adjustment, the wastewater enters product separation unit 4, where degradation products, precipitates, and trace impurities are separated before entering clear water storage tank 44. The purified wastewater can be directly reused as auxiliary water for photolithography processes or further treated to meet discharge standards.

[0030] like Figure 2 As shown, the pretreatment unit 1 includes a grid filter 11, a precision filter assembly 12, an ultrasonic demulsifier 13, and a buffer regulating tank 14 connected in sequence.

[0031] The bar screen filter 11 adopts a stainless steel bar screen structure with a grid spacing of 0.5-1.0 mm, and is used to remove solid particles, photoresist residues, and suspended impurities with a particle size ≥0.5 mm from wastewater. The precision filter assembly 12 adopts a two-stage filtration structure. The first stage is a polypropylene microfiltration membrane filter 121 with a pore size of 0.45 μm, which is used to remove fine suspended particles and colloidal impurities from wastewater. The second stage is a polytetrafluoroethylene ultrafiltration membrane filter 122 with a pore size of 0.22 μm, which is used to further remove large molecular organic matter and undissolved photoresist particles from wastewater.

[0032] The ultrasonic demulsifier 13 uses a high-frequency ultrasonic generator with an ultrasonic frequency of 20-40kHz, a power of 300-500W, and an action time of 5-10 minutes. It is used to break down water-in-oil and oil-in-water emulsions in wastewater, releasing small organic photoresist molecules encapsulated in the emulsion, while simultaneously disrupting the cross-linked structure of the photoresist molecules. The buffer regulating tank 14 has a built-in stirring device with a stirring speed of 200-300 r / min, used to stabilize the wastewater flow rate and composition, and to initially adjust the pH value of the wastewater to 7.0-8.0.

[0033] The advantage of this setup is that before the wastewater enters the electrochemical degradation process, it first removes impurities that could affect electrode operation through bar filtration, precision filtration, ultrasonic demulsification, and buffer regulation, and releases the organic photoresist components encapsulated in the emulsion. This allows the subsequent electrochemical degradation to proceed under relatively stable water quality conditions, reducing electrode clogging, wear, and fluctuations in degradation efficiency.

[0034] like Figure 4 As shown, the online electrochemical degradation unit 2 includes an electrolytic cell body 21, a catalytic electrode assembly 22, an aeration device 23, a heating device 24, and an electrode cleaning assembly 25.

[0035] The electrolytic cell body 21 is made of 316L stainless steel and has a rectangular structure. An ion exchange membrane 26 is installed inside, dividing the electrolytic cell into an anode and a cathode region. This allows ions to pass through while preventing cross-contamination by organic molecules. Flow sensors are installed at the inlet and outlet of the electrolytic cell body 21 to monitor the influent and effluent flow rates in real time.

[0036] The catalytic electrode assembly 22 adopts an alternating anode-cathode arrangement. The anode is a titanium-based ruthenium-iridium coated electrode 221, and the cathode is a graphite electrode 222, with an electrode spacing of 5-10 mm. During operation, under the action of applied voltage and current, the titanium-based ruthenium-iridium coated electrode 221 generates strong oxidizing substances such as hydroxyl radicals and ozone, which oxidize and degrade the organic photoresist components; the graphite electrode 222 undergoes a reduction reaction, which helps to improve the degradation efficiency and inhibits the occurrence of side reactions.

[0037] Aeration device 23 is located at the bottom of the electrolytic cell body 21, using microporous aeration heads to introduce compressed air at an aeration rate of 0.5-1.0 m³ / (m²·h). Heating device 24 uses electric heating tubes, located on the side wall of the electrolytic cell body 21, and is linked to a temperature sensor to control the wastewater temperature in the electrolytic cell at 30-40℃. Electrode cleaning assembly 25 adopts an online spray cleaning structure, located on both sides of the electrodes. A high-pressure spray pump sprays clean water onto the electrode surface to periodically clean deposits and reaction products. The cleaning wastewater is returned to the pretreatment unit 1 for reprocessing.

[0038] The advantages of this setup are that the alternating anode-cathode arrangement can improve the contact efficiency between wastewater and electrodes, the aeration device 23 can enhance wastewater disturbance and remove gaseous products, the heating device 24 can maintain a suitable reaction temperature, and the electrode cleaning assembly 25 can reduce electrode passivation and clogging, thereby ensuring that the online electrochemical degradation unit 2 can operate continuously and stably.

[0039] like Figure 5 As shown, the dynamic alkalinity maintenance unit 3 includes an alkaline storage tank 31, a metering pump 32, a static mixer 33, an online pH monitor 34, and a reflux regulating component 35.

[0040] The alkali storage tank 31 is made of corrosion-resistant PE material and stores a sodium hydroxide-sodium carbonate compound alkali solution, with a sodium hydroxide to sodium carbonate mass ratio of 2:1. The metering pump 32 is a corrosion-resistant precision metering pump and is linked to the online pH monitor 34. The static mixer 33 is located between the electrolytic cell outlet and the alkali addition port, and has multiple layers of staggered guide vanes inside to ensure thorough mixing of the degraded wastewater and alkali solution, with a mixing time of 3-5 minutes.

[0041] The specific adjustment logic includes the following steps: S1: The pH online monitoring instrument 34 collects the wastewater pH value at the outlet of the static mixer 33 in real time; S2: The PLC control system 5 determines whether the wastewater pH value is within the range of 8.5-10.5; S3: If the wastewater pH value is within the range of 8.5-10.5, the wastewater is transported to the product separation unit 4; S4: If the wastewater pH value is not within the range of 8.5-10.5, the PLC control system 5 adjusts the flow rate of the metering pump 32 to control the amount of compound alkali solution added; S5: The reflux adjustment component 35 returns the wastewater with unqualified pH value to the static mixer 33 for remixing and adjustment until the pH value requirement is met.

[0042] The advantage of this setup is that by combining the compound alkaline solution with online pH monitoring, metering pumps, and reflux regulation, the acidic substances generated during the electrochemical degradation process can be dynamically neutralized, avoiding electrode passivation and reduced reaction efficiency caused by a continuous drop in pH value. At the same time, it reduces alkalinity fluctuations and reagent waste caused by manual intermittent regulation.

[0043] like Figure 6 As shown, the product separation unit 4 includes a sedimentation tank 41, a filter press 42, an ultrafiltration device 43, and a clear water storage tank 44.

[0044] The sedimentation tank 41 is used to receive wastewater after alkalinity adjustment. The tank has a built-in stirring device with a stirring speed of 150-200 r / min and a residence time of 10-15 min, so that degradation products and impurities can form sediment. The bottom of the sedimentation tank 41 is equipped with a sludge discharge port for periodically discharging the settled sludge.

[0045] Filter press 42 is a plate and frame filter press used for dewatering settled sludge. The dewatered sludge is disposed of after undergoing harmless treatment, and the filtrate is returned to pretreatment unit 1 for reprocessing. Ultrafiltration unit 43 uses a hollow fiber ultrafiltration membrane with a pore size of 0.01 μm to further remove trace suspended impurities and degrade intermediate products in the wastewater. Clear water storage tank 44 is made of 316L stainless steel and has a built-in level sensor; it is used to store purified wastewater.

[0046] The advantage of this setup is that the sedimentation tank 41 allows degradation products and impurities to settle, the filter press 42 can dewater the settled sludge, the ultrafiltration device 43 can further remove trace suspended impurities and intermediate degradation products, and the clear water storage tank 44 can store the purified wastewater, thereby meeting the purification requirements before wastewater reuse or discharge.

[0047] The PLC control system 5 is electrically connected to the pretreatment unit 1, the online electrochemical degradation unit 2, the dynamic alkalinity maintenance unit 3, and the product separation unit 4. It collects real-time data on temperature, pressure, liquid level, flow rate, pH value, electrode voltage and current, and other parameters from each unit. Through preset programs, it automatically adjusts parameters such as the power of the ultrasonic demulsifier 13, the temperature of the electrolytic cell, the electrode voltage and current, the flow rate of the metering pump 32, and the aeration rate, achieving automated and continuous online operation of the entire system. Simultaneously, the PLC control system 5 includes a manual control mode for easy equipment maintenance and parameter adjustment. It is also equipped with a data acquisition and storage module to record various parameters during the processing, facilitating process optimization and troubleshooting.

[0048] Example 1: A semiconductor chip manufacturing plant uses EUV lithography, generating wastewater containing organic photoresist with a treatment capacity of 8 m³ / d. The wastewater composition is as follows: organic photoresist (mainly negative dialkyl coordinated tin oxide cluster photoresist) with a mass concentration of 800 mg / L, COD of 1200 mg / L, pH of 6.8, and containing a small amount of suspended particles and photoresist residue. The device of this invention is used for online electrochemical degradation and alkalinity maintenance treatment.

[0049] The operating parameters of the device are as follows: In the pretreatment unit 1, the grid filter 11 has a grid spacing of 0.8 mm, and the precision filter assembly 12 adopts a two-stage filtration structure, namely a 0.45 μm polypropylene microfiltration membrane filter 121 and a 0.22 μm polytetrafluoroethylene ultrafiltration membrane filter 122; the ultrasonic demulsifier 13 has a frequency of 30 kHz, a power of 400 W, and an action time of 8 min; the buffer regulating tank 14 has a stirring speed of 250 r / min and initially adjusts the pH value to 7.5.

[0050] In the online electrochemical degradation unit 2, the effective volume of the electrolytic cell is 5 m³, the anode is a titanium-based ruthenium-iridium coated electrode 221, the cathode is a graphite electrode 222, and the electrode spacing is 8 mm; the aeration rate is 0.8 m³ / (m²·h); the electrolytic cell temperature is controlled at 35℃; the electrode voltage is 15 V, and the current density is 20 mA / cm².

[0051] In the dynamic alkalinity maintenance unit 3, a sodium hydroxide-sodium carbonate compound alkaline solution is used with a mass ratio of 2:1; the flow rate of the metering pump 32 is automatically adjusted according to the pH value; the static mixer 33 has a mixing time of 4 minutes; the pH online monitor 34 has a monitoring accuracy of ±0.1 and controls the pH value between 8.5 and 10.5; the reflux ratio is 1:8.

[0052] In product separation unit 4, the stirring speed of sedimentation tank 41 is 180 r / min, and the residence time is 12 min; the membrane pore size of ultrafiltration device 43 is 0.01 μm. PLC control system 5 automatically collects various parameters and adjusts the operating status of related equipment in real time.

[0053] The operating results are as follows: the device operated continuously and stably online for 72 hours, treating 24 m³ of wastewater containing photoresist, with an organic photoresist degradation rate of 99.3%, a COD removal rate of 98.7%, and the effluent pH value remained stable at 9.0-9.5 without significant fluctuations; the COD of the purified wastewater was ≤20 mg / L, meeting the semiconductor industry's reuse standards and can be directly reused as auxiliary water in the photolithography process; the electrodes operated stably without clogging or passivation, and the alkali utilization rate was 96.5%, reducing alkali consumption by more than 30% compared to manual intermittent adjustment; the device produced no secondary pollution, and its operating energy consumption was reduced by 25% compared to conventional electrochemical devices.

[0054] Example 2: A display panel manufacturer uses a functional photoresist processing technology, which generates wastewater containing organic photoresist with a treatment capacity of 12 m³ / d. The wastewater composition is as follows: organic photoresist (mainly photocrosslinkable organic semiconductor photoresist) with a mass concentration of 1500 mg / L, COD of 2200 mg / L, pH of 7.2, containing macromolecular organic additives and suspended impurities. The device of this invention is used for online treatment.

[0055] The operating parameters of the device were adjusted as follows: the ultrasonic demulsifier 13 had a frequency of 35kHz, a power of 450W, and an action time of 10min; the buffer adjustment tank 14 initially adjusted the pH value to 7.8; the electrode spacing of the electrolytic cell was 7mm, the electrode voltage was 18V, and the current density was 25mA / cm²; the aeration rate was 0.9m³ / (m²·h); the electrolytic cell temperature was controlled at 38℃; the amount of compound alkali solution added was dynamically adjusted according to the pH value, controlling the pH value between 9.0 and 10.0; the residence time of the sedimentation tank 41 was 14min, and the reflux ratio was 1:7.

[0056] The operating results are as follows: the device operated continuously and stably online for 72 hours, treating 36 m³ of wastewater containing photoresist, with an organic photoresist degradation rate of 99.5%, a COD removal rate of 98.9%, and an effluent pH value that remained stable between 9.2 and 9.8 with a fluctuation range of ≤0.3; the COD of the purified wastewater was ≤18 mg / L, which can be directly discharged in compliance with standards or reused; the electrode lifespan was stable, and the catalytic activity did not decrease significantly after online cleaning; the alkali utilization rate was 97.2%, and the energy consumption was reduced by 28% compared to conventional devices. The device operated stably without any equipment failures and is suitable for the high-efficiency treatment requirements of functional photoresist wastewater.

[0057] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0058] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A device for online electrochemical degradation and alkalinity maintenance of organic photoresist components, characterized in that, include: The pretreatment unit is used to remove solid particles, suspended impurities, macromolecular organic matter and some additives from organic photoresist wastewater. An online electrochemical degradation unit is connected to the pretreatment unit. The online electrochemical degradation unit adopts a bipolar electrolytic cell structure and has a built-in catalytic electrode assembly for electrochemical oxidation degradation of pretreated organic photoresist wastewater. A dynamic alkalinity maintenance unit is connected to the online electrochemical degradation unit. The dynamic alkalinity maintenance unit uses a sodium hydroxide-sodium carbonate compound alkaline solution and combines online pH monitoring with PLC linkage adjustment to adjust the alkalinity of the wastewater after electrochemical degradation. The product separation unit is connected to the dynamic alkalinity maintenance unit and is used to separate degradation products, precipitates and unreacted trace impurities from the wastewater after electrochemical degradation. The PLC control system is electrically connected to the pretreatment unit, the online electrochemical degradation unit, the dynamic alkalinity maintenance unit, and the product separation unit, and is used to collect the operating parameters of each unit and adjust the operating status of the relevant equipment. The pretreatment unit, the online electrochemical degradation unit, the dynamic alkalinity maintenance unit, and the product separation unit are connected in sequence via corrosion-resistant pipes.

2. The device for online electrochemical degradation and alkalinity maintenance of organic photoresist components according to claim 1, characterized in that, The pretreatment unit includes a bar screen filter, a precision filter assembly, an ultrasonic demulsifier, and a buffer regulating tank connected in sequence. The bar screen filter is used to remove solid particles, photoresist residue, and suspended impurities from the wastewater. The precision filter assembly is used to remove fine suspended particles, colloidal impurities, large organic molecules, and undissolved photoresist particles. The ultrasonic demulsifier is used to break down the emulsion in the wastewater and release small organic photoresist molecules encapsulated in the emulsion. The buffer regulating tank is used to stabilize the wastewater flow rate and composition.

3. The device for online electrochemical degradation and alkalinity maintenance of organic photoresist components according to claim 2, characterized in that, The bar filter adopts a stainless steel bar structure with a bar spacing of 0.5-1.0 mm; the precision filter assembly is a two-stage filtration structure, the first stage is a polypropylene microfiltration membrane filter with a pore size of 0.45 μm, and the second stage is a polytetrafluoroethylene ultrafiltration membrane filter with a pore size of 0.22 μm; the ultrasonic demulsifier has an ultrasonic frequency of 20-40 kHz, a power of 300-500 W, and an action time of 5-10 min; the buffer regulating tank has a built-in stirring device with a stirring speed of 200-300 r / min, and is used to initially adjust the pH value of the wastewater to 7.0-8.

0.

4. The device for online electrochemical degradation and alkalinity maintenance of organic photoresist components according to claim 1, characterized in that, The online electrochemical degradation unit includes an electrolytic cell body, a catalytic electrode assembly, an aeration device, a heating device, and an electrode cleaning assembly. The electrolytic cell body is made of 316L stainless steel, and a partition is installed inside the electrolytic cell body to divide the electrolytic cell body into an anode area and a cathode area.

5. The device for online electrochemical degradation and alkalinity maintenance of organic photoresist components according to claim 4, characterized in that, The partition is an ion exchange membrane, and the catalytic electrode group adopts an alternating anode-cathode arrangement structure. The anode is a titanium-based ruthenium-iridium coated electrode, and the cathode is a graphite electrode. The electrode spacing is 5-10 mm. Flow sensors are respectively installed at the inlet and outlet of the electrolytic cell body.

6. The device for online electrochemical degradation and alkalinity maintenance of organic photoresist components according to claim 4, characterized in that, The aeration device is located at the bottom of the electrolytic cell body and uses a microporous aeration head, with an aeration rate of 0.5-1.0 m³ / (m²·h); the heating device uses an electric heating tube and is located on the side wall of the electrolytic cell body. The heating device is linked with a temperature sensor to control the wastewater temperature in the electrolytic cell body at 30-40℃; the electrode cleaning assembly is an online spray cleaning structure and is located on both sides of the electrodes.

7. The device for online electrochemical degradation and alkalinity maintenance of organic photoresist components according to claim 1, characterized in that, The dynamic alkalinity maintenance unit includes an alkaline solution storage tank, a metering pump, a static mixer, an online pH monitor, and a reflux adjustment component. The alkaline solution storage tank is made of corrosion-resistant PE material. The mass ratio of sodium hydroxide to sodium carbonate in the sodium hydroxide-sodium carbonate compound alkaline solution is 2:

1. The metering pump is linked to the online pH monitor to automatically adjust the flow rate of the metering pump according to the real-time changes in the pH value of the wastewater.

8. The device for online electrochemical degradation and alkalinity maintenance of organic photoresist components according to claim 7, characterized in that, The static mixer is located between the outlet of the electrolytic cell and the alkali addition port. The static mixer has multiple layers of staggered guide vanes inside, and the mixing time is 3-5 minutes. The pH online monitoring instrument is located at the outlet of the static mixer, with a monitoring accuracy of ±0.1, and is used to control the pH value of the wastewater between 8.5 and 10.

5. The reflux adjustment component includes a reflux pipe and a reflux pump, which is used to reflux wastewater with an unqualified pH value after adjustment back to the static mixer for readjustment, with a reflux ratio of 1:5-1:

10.

9. The device for online electrochemical degradation and alkalinity maintenance of organic photoresist components according to claim 1, characterized in that, The product separation unit includes a sedimentation tank, a filter press, an ultrafiltration device, and a clear water storage tank. The sedimentation tank has a built-in stirring device with a stirring speed of 150-200 r / min and a residence time of 10-15 min. The filter press is a plate and frame filter press, and the filtrate after filtration is returned to the pretreatment unit. The ultrafiltration device uses a hollow fiber ultrafiltration membrane with a pore size of 0.01 μm. The clear water storage tank is made of 316L stainless steel and has a built-in liquid level sensor.

10. The device for online electrochemical degradation and alkalinity maintenance of organic photoresist components according to claim 1, characterized in that, The PLC control system is used to collect temperature, pressure, liquid level, flow rate, pH value, electrode voltage and electrode current parameters in real time, and automatically adjust the power of the ultrasonic demulsifier, the temperature of the electrolytic cell, the electrode voltage, the electrode current, the flow rate of the metering pump and the aeration rate through a preset program. The PLC control system is also equipped with a manual control mode and a data acquisition and storage module.

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