A purification process for waste developer liquid in liquid crystal panel factories

Abstract

The present application relates to the field of wastewater treatment technology, and specifically discloses a purification process for developer waste liquid in liquid crystal panel factories. A purification process for developer waste liquid in liquid crystal panel factories comprises the following steps: S1, adding a composite acid precipitation liquid to the developer waste liquid, and simultaneously performing ultraviolet light irradiation treatment to obtain a suspension; S2, adding an amphiphilic coagulant to the suspension and stirring the reaction, and then standing; the amphiphilic coagulant is acrylamide-dimethyldiallylammonium chloride-methacrylic acid glycidyl ester terpolymer; S3, centrifuging the solution system after standing in S2 to obtain a tetramethylammonium salt solution; S4, using a bipolar membrane electrodeionization device to convert the tetramethylammonium salt solution into a TMAH solution. The treatment process of the present application effectively improves the purification and removal effect of the photoresist in the developer waste liquid, and effectively enhances the reuse reliability of TMAH.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and more specifically, to a purification process for waste developer liquid in liquid crystal panel factories. Background Art

[0002] The array manufacturing process for LCD panel manufacturing includes cleaning, film formation, photoresist coating, exposure, development, etching, and photoresist stripping. The photoresist used in this process changes its properties after exposure and is dissolved and removed by an alkaline developer (2.38wt% tetramethylammonium hydroxide solution) during the development process. The tetramethylammonium hydroxide solution containing the dissolved photoresist discharged during the development process is the developer waste. In addition to the main component, TMAH, the developer waste also contains photoresist. Photoresist is composed of resin, photosensitive material, solvent, and additives. A key property of the photoresist in the developer waste is that it is soluble in strong bases and can be converted into insoluble matter and precipitated under acidic conditions.

[0003] Currently, the primary purification process for developer wastewater is neutralization precipitation-membrane separation. Neutralization precipitation utilizes the alkaline-solubility and acid-precipitation properties of photoresists. Adjusting the pH with dilute sulfuric acid or hydrochloric acid causes organic matter to precipitate and separate. Due to the decreased solubility of organic matter such as resins and photosensitive materials in the photoresist, flocculent precipitates are formed. A coagulant is then added to promote flocculent aggregation. After centrifugation to remove the solid phase, a filtrate containing TMAH salt is obtained. The TMAH salt is then converted to an alkaline solution using an ion exchange resin. The resulting TMAH solution, after concentration adjustment, can be reused as a developer.

[0004] While the aforementioned methods are effective for purifying developer wastewater, the advancement of advanced LCD panel manufacturing processes, such as those used in Gen 8.5 and higher, has led to a significant increase in the content of photosensitive materials (such as diazoquinone compounds) in photoresists, presenting new challenges for the purification of developer wastewater. In these wastewaters, the photosensitive material and resin form a highly stable colloidal system through π-π stacking and hydrogen bonding. Traditional single acids can only adjust the pH but are unable to effectively disrupt the hydrophobic interactions within the colloid, significantly reducing the acidification rate of the photoresist. Furthermore, the flocs formed by high concentrations of photosensitive material are extremely viscous and easily entangled. Traditional coagulants (such as PAM) have difficulty penetrating these viscous networks due to their simple molecular structure, resulting in substandard turbidity in the filtrate after centrifugation. These challenges hinder the efficient removal of photoresist from developer wastewater in advanced processes, severely impacting the subsequent recovery purity and reliability of TMAH. Developing targeted purification processes to improve photoresist removal is urgently needed. Summary of the Invention

[0005] In order to improve the purification and removal effect of photoresist in developer waste liquid generated by high-end processes and enhance the reliability of TMAH reuse, the present application provides a purification treatment process for developer waste liquid in liquid crystal panel factories.

[0006] The present application provides a purification process for waste developer liquid from a liquid crystal panel factory using the following technical solutions:

[0007] A purification process for waste developer in a liquid crystal panel factory comprises the following steps:

[0008] S1. Adding a composite acid-precipitated liquid to a developer waste liquid to adjust the pH to 2.0-3.0, stirring and reacting for 2-3 hours to obtain a suspension, and irradiating the developer waste liquid system with ultraviolet light during the stirring reaction; the composite acid-precipitated liquid includes a phosphoric acid solution, a trifluoromethanesulfonic acid solution, a gel breaker, and modified β-cyclodextrin;

[0009] S2. Adding an amphiphilic coagulant to the suspension at a dosage of 90-100 mg / L, stirring and reacting for 2-3 hours, and then standing for 3-5 hours; the amphiphilic coagulant is a terpolymer of acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate;

[0010] S3, centrifuging the solution system after S2 was allowed to stand to obtain a tetramethylammonium salt solution;

[0011] S4. Fill the acid chamber of the bipolar membrane electrodeionization device with an acidic cation exchange resin, and pass the tetramethylammonium salt solution obtained in S3 into the salt chamber. After the bipolar membrane electrodeionization device is powered on, the current density is controlled to be 30-50 mA cm -2 , collect the TMAH solution generated in the alkali chamber.

[0012] By adopting the above technical solution, due to the combination of phosphoric acid and trifluoromethanesulfonic acid, phosphoric acid provides a buffer to stabilize pH, and trifluoromethanesulfonic acid destroys the ester bonds and ether bonds in the photoresist molecules through super acidity, thereby destroying the hydrophobic stacking structure of the photosensitive material and the resin; thereby, the acid precipitation rate of the photoresist can be effectively enhanced, which is beneficial to the subsequent full removal of the photoresist in the waste liquid. During the acid precipitation and stirring process, ultraviolet light irradiation can, on the one hand, destroy and interrupt the chemical bonds between the photosensitive material and the resin, thereby effectively destroying the hydrophobic interaction of the colloid, thereby facilitating the improvement of the acid precipitation rate; on the other hand, ultraviolet light irradiation activates the breaker to generate free radicals, which attack the benzene ring, double bond and other structures of the photoresist through the free radicals, thereby accelerating the breaker reaction, which is beneficial to the full precipitation of the photoresist, and thus facilitates the subsequent adsorption and removal. The cationic unit of the amphiphilic coagulant neutralizes the colloid charge, the epoxy group forms a covalent bond with the photoresist, and the acrylamide unit adjusts the hydrophilicity to promote the efficient aggregation of flocs. Finally, through centrifugal separation and ion exchange with the BMEDI device, high-purity purification treatment of TMAH is achieved, effectively enhancing the reliability of TMAH reuse.

[0013] Optionally, the wavelength of the ultraviolet light is 254-365 nm, and the power density is 50-100 mW / cm².

[0014] By adopting the above technical solution, the power density of the above ultraviolet light wavelength and the ultraviolet light in the above wavelength range have higher photon energy, so it can effectively break the chemical bond between the photosensitive material and the resin, thereby effectively destroying the hydrophobic interaction of the colloid, making it easy for the photoresist to precipitate, and can effectively excite the breaker to produce free radicals, accelerate the breaker reaction, and further improve the acid precipitation rate of the photoresist.

[0015] Optionally, the mass ratio of the phosphoric acid solution to the trifluoromethanesulfonic acid solution in the composite acid precipitation liquid is (2-3):1; the mass of the breaker is 2.5%-5% of the total mass of the phosphoric acid solution and the trifluoromethanesulfonic acid solution; and the mass of the modified β-cyclodextrin is 0.5%-1% of the total mass of the phosphoric acid solution and the trifluoromethanesulfonic acid solution.

[0016] Optionally, the mass concentration of the phosphoric acid solution is 23%-30%; the concentration of the trifluoromethanesulfonic acid solution is 5%-10%.

[0017] By adopting this technical solution, the ratio of the composite acid precipitation solution ensures that the breaker fully exerts its effect in severing photoresist molecular chains while also enriching the decomposition products through the modified β-cyclodextrin, preventing their repolymerization. The concentration of 23%-30% phosphoric acid solution and 5%-10% trifluoromethanesulfonic acid solution ensures a balance between acid strength and buffering capacity during the acid precipitation process.

[0018] Optionally, the modified β-cyclodextrin is prepared by the following method:

[0019] A1. Dissolve β-cyclodextrin in deionized water, add sodium dithiocarbamate and potassium carbonate, react at 50-60°C under nitrogen for 5-6 hours, then cool and centrifuge to obtain dithiocarbamate-β-cyclodextrin;

[0020] A2. Add dithiocarbamate-β-cyclodextrin to DMSO, add cinnamoyl chloride and triethylamine, and react at room temperature for 10-12 hours. After the reaction is completed, centrifuge and dry to obtain modified β-cyclodextrin.

[0021] By adopting the above technical solution, the modified β-cyclodextrin is grafted stepwise with sodium dithiocarbamate and cinnamoyl chloride to introduce dithiocarbamate and cinnamate groups. The dithiocarbamate groups generate sulfur radicals under ultraviolet light, catalyzing the cleavage of double bonds in the photosensitive material and enhancing the recognition of diazoquinone compounds through sulfur-π interactions. The cinnamate groups undergo a cross-linking reaction under ultraviolet light to form a three-dimensional network structure, which fixes the captured photoresist fragments. At the same time, the surface charge is reversed after cross-linking, promoting electrostatic attraction with negatively charged colloids. This action can reduce the viscosity of the flocs formed by the precipitated photosensitive material, preventing agglomeration, thereby facilitating the subsequent adsorption and removal of the flocs by a coagulant aid. This, in turn, reduces the content of photoresist impurities in the filtrate after centrifugation, thereby improving the purification and removal of photoresist in the wastewater.

[0022] Optionally, in A1, the mass ratio of the β-cyclodextrin, deionized water, sodium dithiocarbamate and potassium carbonate is 1: (8-10): (0.4-0.5): (0.1-0.2).

[0023] Optionally, in A2, the mass ratio of the dithiocarbamate-β-cyclodextrin, DMSO, cinnamoyl chloride and triethylamine is 1:(5-7):(0.2-0.3):(0.1-0.2).

[0024] Acrylamide, dimethyldiallyl ammonium chloride and glycidyl methacrylate are added to deionized water and stirred for 20-30 minutes. Then ammonium persulfate is added and stirred at 60-70°C for 4-6 hours under nitrogen protection. Then, the mixture is filtered, washed and dried to obtain an acrylamide-dimethyldiallyl ammonium chloride-glycidyl methacrylate terpolymer.

[0025] By adopting the above technical solution, acrylamide, dimethyldiallylammonium chloride, and glycidyl methacrylate are copolymerized to form a polymer structure with multiple action mechanisms. The DMDAAC unit provides cationic charge to neutralize the negative charge on the surface of the photoresist colloid; the epoxy group of the GMA unit undergoes a ring-opening reaction with the phenolic hydroxyl and carboxyl groups of the photoresist to form a covalent bond bridge; the AM unit adjusts the hydrophilicity to prevent the flocs from being excessively hydrophobic. The precise amount of each monomer and ammonium persulfate is controlled to maintain the molecular weight of the coagulant aid at 10 5 -10 6 Da, while ensuring charge neutralization and bridging capabilities, reduces solution viscosity. Compared to traditional PAM coagulants, the terpolymer of this application significantly improves the flocculation effect and solid-liquid separation efficiency of high-viscosity flocs, reducing the turbidity of the filtrate after centrifugation to below 10 NTU.

[0026] Optionally, the mass ratio of acrylamide, dimethyldiallylammonium chloride, glycidyl methacrylate and deionized water is 10:(8-10):(3-5):(70-75); and the amount of ammonium persulfate added is 2.5%-5% of the total mass of the monomers.

[0027] Optionally, the gel breaker is any one of mercaptoethanol and dithiothreitol.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. This application uses a composite acid precipitation liquid composed of phosphoric acid and trifluoromethanesulfonic acid. Phosphoric acid provides a buffer to stabilize pH and prevent TMAH from decomposing. Trifluoromethanesulfonic acid destroys the ester bonds and ether bonds in the photoresist molecules with its super acidity, and disintegrates the hydrophobic stacking structure of the colloid. At the same time, combined with ultraviolet light irradiation during the acid precipitation process, it can not only directly destroy the chemical bonds between the resin and the photosensitive material, but also activate the gel breaker to generate free radicals, attack the benzene ring, double bond and other structures of the photoresist, and accelerate the gel breaking reaction. The dithiocarbamate group on the modified β-cyclodextrin generates thiol free radicals under ultraviolet light, which further catalyzes the breakage of the double bond of the photosensitive material. Under the synergistic effect of multiple effects, the photoresist acid precipitation rate is greatly improved from the low level of the traditional process, effectively solving the problem of the difficulty of precipitating photoresist in the waste liquid of high-level processes, and thus helping to improve the purification and removal effect of photoresist in the developer waste liquid generated by high-level processes.

[0030] 2. The amphiphilic coagulant designed in this application is a terpolymer of acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate, in which the DMDAAC unit provides cationic charge to neutralize the negative charge on the colloid surface; the epoxy group of the GMA unit undergoes a ring-opening reaction with the phenolic hydroxyl and carboxyl groups of the photoresist to form a covalent bond bridge; the AM unit adjusts the hydrophilicity to prevent the flocs from being excessively hydrophobic. The multiple action mechanisms enable it to effectively penetrate the high-viscosity floc network and promote the efficient aggregation of flocs. At the same time, after the modified β-cyclodextrin is irradiated with ultraviolet light, the cinnamate groups cross-link to form a three-dimensional network, which reduces the viscosity of the flocs and prevents them from agglomerating. The synergistic effect of the two significantly improves the flocculation effect, reducing the filtrate after centrifugation to below 10 NTU, and improving the problem of high-viscosity flocs being difficult to separate.

[0031] 3. This application utilizes the synergistic effects of a composite acid solution, ultraviolet light, a gel breaker, and modified β-cyclodextrin to efficiently remove photoresist from wastewater. An amphiphilic coagulant and centrifugal separation further reduce the impurity content in the filtrate. In the BMEDI device processing phase, an acidic cation exchange resin filled in the acid chamber selectively adsorbs residual impurities. Combined with a precisely controlled current density of 30-50 mA cm², this enables efficient migration of tetramethylammonium ions, effectively increasing TMAH recovery and the reliability of TMAH reuse. This meets the stringent developer quality requirements of high-end LCD panel manufacturing processes while reducing production costs and environmental impact. DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to the embodiments.

[0033] Preparation Example of Modified β-Cyclodextrin

[0034] Preparation Example 1

[0035] Modified β-cyclodextrin is prepared by the following method:

[0036] A1. Dissolve 10 g of β-cyclodextrin in 80 g of deionized water, add 4 g of sodium dithiocarbamate and 1 g of potassium carbonate, and react at 50 ° C for 5 h under nitrogen protection. After the reaction, cool to room temperature, centrifuge, and dry at 40 ° C to obtain dithiocarbamate-β-cyclodextrin;

[0037] A2. Disperse 10 g of dithiocarbamate-β-cyclodextrin in 50 g of DMSO, add 2 g of cinnamoyl chloride and 1 g of triethylamine, and react at room temperature for 10 h. After the reaction, centrifuge and dry at 40°C to obtain modified β-cyclodextrin.

[0038] Preparation Example 2

[0039] Modified β-cyclodextrin is prepared by the following method:

[0040] A1. Dissolve 10 g of β-cyclodextrin in 90 g of deionized water, add 4.5 g of sodium dithiocarbamate and 1.5 g of potassium carbonate, and react at 55 ° C for 5.5 h under nitrogen protection. After the reaction, cool to room temperature, centrifuge, and dry at 40 ° C to obtain dithiocarbamate-β-cyclodextrin;

[0041] A2. Disperse 10 g of dithiocarbamate-β-cyclodextrin in 60 g of DMSO, add 2.5 g of cinnamoyl chloride and 1.5 g of triethylamine, and react at room temperature for 11 h. After the reaction is completed, centrifuge and dry at 40°C to obtain modified β-cyclodextrin.

[0042] Preparation Example 3

[0043] Modified β-cyclodextrin is prepared by the following method:

[0044] A1. Dissolve 10 g of β-cyclodextrin in 100 g of deionized water, add 5 g of sodium dithiocarbamate and 2 g of potassium carbonate, and react at 60 ° C for 6 h under nitrogen protection. After the reaction, cool to room temperature, centrifuge, and dry at 40 ° C to obtain dithiocarbamate-β-cyclodextrin;

[0045] A2. Disperse 10 g of dithiocarbamate-β-cyclodextrin in 70 g of DMSO, add 3 g of cinnamoyl chloride and 2 g of triethylamine, and react at room temperature for 12 h. After the reaction, centrifuge and dry at 40°C to obtain modified β-cyclodextrin.

[0046] Preparation Example of Acrylamide-Dimethyldiallylammonium Chloride-Glycidyl Methacrylate Terpolymer

[0047] Preparation Example 4

[0048] 100 g of acrylamide, 80 g of dimethyldiallyl ammonium chloride, and 30 g of glycidyl methacrylate were added to 700 g of deionized water and stirred for 20 min. Then, 5.25 g of ammonium persulfate was added and stirred at 60 ° C under nitrogen protection for 4 h. Then, the acrylamide-dimethyldiallyl ammonium chloride-glycidyl methacrylate terpolymer was obtained by filtration, washing, and drying.

[0049] Preparation Example 5

[0050] 100 g of acrylamide, 90 g of dimethyldiallyl ammonium chloride, and 40 g of glycidyl methacrylate were added to 730 g of deionized water and stirred for 25 min. Then, 9.2 g of ammonium persulfate was added and stirred at 65 ° C. under nitrogen protection for 5 h. Then, the mixture was filtered, washed, and dried to obtain acrylamide-dimethyldiallyl ammonium chloride-glycidyl methacrylate terpolymer.

[0051] Preparation Example 6

[0052] 100 g of acrylamide, 100 g of dimethyldiallyl ammonium chloride, and 50 g of glycidyl methacrylate were added to 750 g of deionized water and stirred for 30 min. Then, 12.5 g of ammonium persulfate was added and stirred at 70 ° C under nitrogen protection for 6 h. Then, the acrylamide-dimethyldiallyl ammonium chloride-glycidyl methacrylate terpolymer was obtained by filtration, washing, and drying.

[0053] Example

[0054] Example 1

[0055] A purification process for waste developer in a liquid crystal panel factory comprises the following steps:

[0056] S1. Add the composite acid precipitation liquid to 10 kg of developer waste liquid to adjust the pH to 2.0, stir and react for 2 hours to obtain a suspension. During the stirring reaction, the developer waste liquid system is irradiated with ultraviolet light at a wavelength of 254 nm and a power density of 50 mW / cm². The material ratio of the composite acid precipitation liquid is shown in Table 1, wherein the mass concentration of the phosphoric acid solution is 23%; the concentration of the trifluoromethanesulfonic acid solution is 5%; the gel breaker is selected from mercaptoethanol, and the modified β-cyclodextrin is selected from the modified β-cyclodextrin prepared in Preparation Example 1;

[0057] S2. Add an amphiphilic coagulant to the suspension at a dosage of 90 mg / L, stir and react for 2 hours, and then let it stand for 3 hours; the amphiphilic coagulant is acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 4;

[0058] S3, centrifuging the solution system after S2 was allowed to stand at 3000 rpm for 30 min to obtain a tetramethylammonium salt solution;

[0059] S4: Fill the acid chamber of the bipolar membrane electrodeionization device with D001 styrene-based cation exchange resin, and pass the tetramethylammonium salt solution obtained in S3 into the salt chamber. After the bipolar membrane electrodeionization device is powered on, the current density is controlled to be 30 mA cm -2 , collect the TMAH solution generated in the alkali chamber.

[0060] Example 2

[0061] A purification process for waste developer in a liquid crystal panel factory comprises the following steps:

[0062] S1. Add the composite acid precipitation liquid to 10 kg of developer waste liquid to adjust the pH to 2.5, stir and react for 2.5 hours to obtain a suspension. During the stirring reaction, the developer waste liquid system is irradiated with ultraviolet light at a wavelength of 300 nm and a power density of 80 mW / cm². The material ratio of the composite acid precipitation liquid is shown in Table 1, wherein the mass concentration of the phosphoric acid solution is 26%; the concentration of the trifluoromethanesulfonic acid solution is 8%; the gel breaker is dithiothreitol, and the modified β-cyclodextrin is selected from the modified β-cyclodextrin prepared in Preparation Example 2;

[0063] S2. Add an amphiphilic coagulant to the suspension at a dosage of 95 mg / L, stir and react for 2.5 hours, and then let it stand for 4 hours; the amphiphilic coagulant is acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 4;

[0064] S3, centrifuging the solution system after S2 was allowed to stand at 3000 rpm for 30 min to obtain a tetramethylammonium salt solution;

[0065] S4: Fill the acid chamber of the bipolar membrane electrodeionization device with D001 styrene-based cation exchange resin, and pass the tetramethylammonium salt solution obtained in S3 into the salt chamber. After the bipolar membrane electrodeionization device is powered on, the current density is controlled to be 40 mA cm -2 , collect the TMAH solution generated in the alkali chamber.

[0066] Example 3

[0067] A purification process for waste developer in a liquid crystal panel factory comprises the following steps:

[0068] S1. Add the composite acid precipitation liquid to 10 kg of developer waste liquid to adjust the pH to 3.0, stir and react for 3 hours to obtain a suspension. During the stirring reaction, the developer waste liquid system is irradiated with ultraviolet light at a wavelength of 365 nm and a power density of 100 mW / cm². The material ratio of the composite acid precipitation liquid is shown in Table 1, wherein the mass concentration of the phosphoric acid solution is 30%; the concentration of the trifluoromethanesulfonic acid solution is 10%; the gel breaker is selected from mercaptoethanol, and the modified β-cyclodextrin is selected from the modified β-cyclodextrin prepared in Preparation Example 3;

[0069] S2. Add an amphiphilic coagulant to the suspension at a dosage of 10 mg / L, stir and react for 3 hours, and then let it stand for 5 hours; the amphiphilic coagulant is acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 4;

[0070] S3, centrifuging the solution system after S2 was allowed to stand at 3000 rpm for 30 min to obtain a tetramethylammonium salt solution;

[0071] S4: Fill the acid chamber of the bipolar membrane electrodeionization device with D001 styrene-based cation exchange resin, and pass the tetramethylammonium salt solution obtained in S3 into the salt chamber. After the bipolar membrane electrodeionization device is powered on, the current density is controlled to 50 mA cm -2 , collect the TMAH solution generated in the alkali chamber.

[0072] Table 1 Raw materials and proportions of composite acid separation solutions in Examples 1-3 (kg)

[0073]

[0074] Example 4

[0075] A purification process for waste developer liquid in a liquid crystal panel factory is provided. The difference from Example 1 is that the amphiphilic coagulant in this embodiment is the acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 5.

[0076] Example 5

[0077] A purification process for waste developer liquid in a liquid crystal panel factory is provided. The difference from Example 1 is that the amphiphilic coagulant in this embodiment is the acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 6.

[0078] Comparative Example

[0079] Comparative Example 1

[0080] A purification process for waste developer in a liquid crystal panel factory comprises the following steps:

[0081] S1. Add 15% hydrochloric acid solution to 10 kg of developer waste liquid to adjust the pH to 2.0, and stir for 2 hours to obtain a suspension;

[0082] S2. Add polyacrylamide coagulant to the suspension at a dosage of 90 mg / L, stir and react for 2 hours, and then let it stand for 3 hours;

[0083] S3, centrifuging the solution system after S2 was allowed to stand at 3000 rpm for 30 min to obtain a tetramethylammonium salt solution;

[0084] S4: Fill the acid chamber of the bipolar membrane electrodeionization device with D001 styrene-based cation exchange resin, and pass the tetramethylammonium salt solution obtained in S3 into the salt chamber. After the bipolar membrane electrodeionization device is powered on, the current density is controlled to be 30 mA cm -2 , collect the TMAH solution generated in the alkali chamber.

[0085] Comparative Example 2

[0086] A purification process for waste developer liquid in a liquid crystal panel factory is provided. The difference from Example 1 is that an equal amount of hydrochloric acid solution with a mass concentration of 15% is used in this comparative example S1 to replace the composite acid precipitation liquid in S1, and the remaining steps are the same as those in Example 1.

[0087] Comparative Example 3

[0088] A purification process for waste developer in a liquid crystal panel factory is disclosed. The difference from Example 1 is that in this comparative example S1, no ultraviolet light irradiation treatment is performed during the acid precipitation and stirring reaction process, and the remaining steps are the same as those in Example 1.

[0089] Comparative Example 4

[0090] A purification process for waste developer in a liquid crystal panel factory is provided. The difference from Example 1 is that polyacrylamide is used as a coagulant aid in this comparative example S2, and the remaining steps are the same as those in Example 1.

[0091] Detection test

[0092] 1. Determination of acid precipitation rate

[0093] High-performance liquid chromatography (HPLC) was used to determine the concentrations of photoresist resin and photosensitive material in the wastewater before and after step S1. Chromatographic conditions included a C18 column (150 mm × 4.6 mm), a mobile phase of methanol / water (70:30, v / v), a flow rate of 1.0 mL / min, and a UV detector at 254 nm. The acid precipitation rate was calculated based on the concentrations of photoresist resin and photosensitive material in the wastewater before and after step S1. The results are shown in Table 2.

[0094] 2. Determination of turbidity of filtrate after centrifugation

[0095] The turbidity of the filtrate after step S3 was measured using a HACH2100Q turbidity meter. The test results are shown in Table 2.

[0096] 3. Residual amount of photoresist in TMAH solution

[0097] Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was used to detect the residual photoresist content in the TMAH solution collected by S4. The detection results are shown in Table 2.

[0098] Table 2 Test results

[0099]

[0100] As can be seen from Table 2, in the treatment processes of Examples 1-5 of the present application, the acid precipitation rate after step S1 all reached more than 97.6%, while the acid precipitation rate after step S1 in Comparative Example 1 using traditional single hydrochloric acid treatment was only 67.4%, and that in Comparative Example 2 was 69.4%. The acid precipitation rates of Comparative Examples 1 and 2 were both lower than those of the present application. This shows that the composite acid precipitation liquid used in the present application can better promote the precipitation of photoresist in developer waste liquid, provide a stable pH buffer environment through phosphoric acid to prevent TMAH decomposition, and trifluoromethanesulfonic acid destroys the ester bond and ether bond of the photoresist, cooperates with ultraviolet light to excite the breaker to accelerate the breaker reaction, and activates the sulfur-π interaction of the modified β-cyclodextrin, forming a "acidolysis-photocatalysis-molecular capture" triple mechanism, completely destroying the colloid stability, thereby fully promoting the precipitation of the photoresist. In Comparative Example 3, which did not undergo UV irradiation treatment, the acid precipitation rate dropped to 76.7%, demonstrating the key role of UV light in the generation of free radicals and the cross-linking of modified β-cyclodextrin. The modified β-cyclodextrin can further improve the acid precipitation rate through the photoresponsive properties of dithiocarbamate and cinnamate groups.

[0101] The turbidity of the filtrate in Examples 1-5 was less than 8.3 NTU, while the turbidity of the filtrate in Comparative Example 1, which used a traditional PAM coagulant, reached 156 NTU after centrifugation. The turbidity in Comparative Example 4, which used PAM instead of an amphiphilic coagulant, was still as high as 164 NTU, indicating that the amphiphilic coagulant of the present application has a good flocculation and adsorption effect.

[0102] The residual amount of photoresist in the TMAH solution of Examples 1-5 was less than 5.4 ppm, while the residual amount in Comparative Example 1 was as high as 73.2 ppm. This indicates that the treatment process of the present application is effective in purifying and removing photoresist from developer waste liquid. More than 95% of organic matter is first removed through composite acid precipitation combined with ultraviolet irradiation treatment and centrifugal separation. The D001 type cation exchange resin in the BMEDI device, combined with a current density of 30-50 mA cm⁻², efficiently migrates tetramethylammonium ions to the base chamber through the dual effects of electromigration and ion exchange. At the same time, the acid chamber resin adsorbs residual impurities, ensuring the purity of TMAH and helping to enhance the reliability of TMAH reuse.

[0103] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A purification process for waste developer liquid in a liquid crystal panel factory, characterized in that: The steps include: S1. Adding a composite acid-precipitated liquid to a developer waste liquid to adjust the pH to 2.0-3.0, stirring and reacting for 2-3 hours to obtain a suspension, and irradiating the developer waste liquid system with ultraviolet light during the stirring reaction; the composite acid-precipitated liquid includes a phosphoric acid solution, a trifluoromethanesulfonic acid solution, a gel breaker, and modified β-cyclodextrin; S2. Adding an amphiphilic coagulant to the suspension at a dosage of 90-100 mg / L, stirring and reacting for 2-3 hours, and then standing for 3-5 hours; the amphiphilic coagulant is a terpolymer of acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate; S3, centrifuging the solution system after S2 was allowed to stand to obtain a tetramethylammonium salt solution; S4. Fill the acid chamber of the bipolar membrane electrodeionization device with an acidic cation exchange resin, pass the tetramethylammonium salt solution obtained in S3 into the salt chamber, control the current density to 30-50 mA·cm-2 after the bipolar membrane electrodeionization device is powered on, and collect the TMAH solution generated in the base chamber; The modified β-cyclodextrin is prepared by the following method: A1. Dissolve β-cyclodextrin in deionized water, add sodium dithiocarbamate and potassium carbonate, react at 50-60°C under nitrogen for 5-6 hours, then cool and centrifuge to obtain dithiocarbamate-β-cyclodextrin; A2. Add dithiocarbamate-β-cyclodextrin to DMSO, add cinnamoyl chloride and triethylamine, and react at room temperature for 10-12 hours. After the reaction is completed, centrifuge and dry to obtain modified β-cyclodextrin.

2. The purification process for waste developer liquid in a liquid crystal panel factory according to claim 1, characterized in that: The wavelength of the ultraviolet light is 254-365nm, and the power density is .

3. The purification process for waste developer liquid in a liquid crystal panel factory according to claim 1, characterized in that: The mass ratio of the phosphoric acid solution to the trifluoromethanesulfonic acid solution in the composite acid precipitation liquid is (2-3):1; the mass of the gel breaker is 2.5%-5% of the total mass of the phosphoric acid solution and the trifluoromethanesulfonic acid solution; and the mass of the modified β-cyclodextrin is 0.5%-1% of the total mass of the phosphoric acid solution and the trifluoromethanesulfonic acid solution.

4. The purification process for waste developer liquid in a liquid crystal panel factory according to claim 3, characterized in that: The mass concentration of the phosphoric acid solution is 23%-30%; the concentration of the trifluoromethanesulfonic acid solution is 5%-10%.

5. The purification process for waste developer liquid in a liquid crystal panel factory according to claim 1, characterized in that: In A1, the mass ratio of the β-cyclodextrin, deionized water, sodium dithiocarbamate and potassium carbonate is 1: (8-10): (0.4-0.5): (0.1-0.2).

6. The purification process for waste developer liquid in a liquid crystal panel factory according to claim 5, characterized in that: In A2, the mass ratio of dithiocarbamate-β-cyclodextrin, DMSO, cinnamoyl chloride and triethylamine is 1:(5-7):(0.2-0.3):(0.1-0.2).

7. The purification process for waste developer liquid in a liquid crystal panel factory according to claim 1, characterized in that: The acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer is prepared by the following method: Acrylamide, dimethyldiallyl ammonium chloride and glycidyl methacrylate are added to deionized water and stirred for 20-30 minutes. Then ammonium persulfate is added and stirred at 60-70°C for 4-6 hours under nitrogen protection. Then, the mixture is filtered, washed and dried to obtain an acrylamide-dimethyldiallyl ammonium chloride-glycidyl methacrylate terpolymer.

8. The purification process for waste developer liquid in a liquid crystal panel factory according to claim 7, characterized in that: The mass ratio of acrylamide, dimethyldiallylammonium chloride, glycidyl methacrylate and deionized water is 10:(8-10):(3-5):(70-75); the amount of ammonium persulfate added is 2.5%-5% of the total mass of the monomers.

9. The purification process for waste developer liquid in a liquid crystal panel factory according to claim 1, characterized in that: The gel breaker is any one of mercaptoethanol and dithiothreitol.

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