Purification treatment process for liquid crystal panel factory developing liquid waste

Abstract

The invention relates to the technical field of wastewater treatment, and particularly discloses a purification treatment process for liquid crystal panel factory developing liquid waste. The purification treatment process for the liquid crystal panel factory developing solution waste liquid comprises the following steps: S1, adding a composite acid precipitation solution into the developing solution waste liquid, and meanwhile, carrying out ultraviolet irradiation treatment to obtain a suspension; s2, adding an amphiphilic coagulant aid into the suspension, stirring for reaction, and standing; the amphiphilic coagulant aid is an acrylamide-dimethyl diallyl ammonium chloride-glycidyl methacrylate terpolymer, and the amphiphilic coagulant aid is an acrylamide-dimethyl diallyl ammonium chloride-glycidyl methacrylate terpolymer; s3, carrying out centrifugal separation on the solution system after standing in S2 to obtain a tetramethyl ammonium salt solution; and S4, converting the tetramethyl ammonium salt solution into a TMAH solution by using bipolar membrane electrodeionization equipment. According to the treatment process, the purification and removal effect on the photoresist in the waste developing solution is effectively improved, and the recycling reliability of the TMAH is effectively enhanced.

Description

Technical Field

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

[0002] The array process in liquid crystal panel manufacturing includes processes such as cleaning, film formation, photoresist coating, exposure, development, etching, and photoresist stripping. After exposure, the properties of the photoresist used in the process change and it is dissolved and removed by an alkaline developer (2.38 wt% tetramethylammonium hydroxide solution) in the development process. The tetramethylammonium hydroxide solution dissolved with the photoresist discharged in the development process is the developer waste liquid. In addition to the main component TMAH, the developer waste liquid also contains photoresist. The photoresist is composed of components such as resin, photosensitive material, solvent, and additive. An important property of the photoresist in the developer waste liquid is that it is soluble in strong alkali and can be converted into insoluble matter and precipitated under acidic conditions.

[0003] Currently, the main purification treatment process for the developer waste liquid is the neutralization precipitation - membrane separation method. Neutralization precipitation utilizes the "alkali-soluble and acid-precipitated" characteristics of the photoresist. The pH is adjusted by dilute sulfuric acid or hydrochloric acid to precipitate and separate the organic matter. Organic matters such as resin and photosensitive material in the photoresist form flocculent precipitates due to the decrease in solubility, and then a coagulant aid is added to promote the aggregation of the flocs. After centrifugal separation, the solid phase is removed to obtain a filtrate containing TMAH salt. Then, the TMAH salt is converted into an alkaline solution through an ion exchange resin. The obtained TMAH solution can be used as a developer again after concentration adjustment.

[0004] Although the above method can purify the developer waste liquid, with the development of the liquid crystal panel process towards high-order, such as the significant increase in the content of photosensitive materials (such as diazoquinone compounds) in the photoresist used above the 8.5-generation line, new challenges are faced in the purification treatment of the developer waste liquid. In such waste liquid, the photosensitive material and the resin form a colloidal system with extremely strong stability through π-π stacking and hydrogen bonding. The traditional single acid can only adjust the pH but cannot effectively destroy the hydrophobic interaction of the colloid, resulting in a significant reduction in the acid precipitation rate of the photoresist. At the same time, the flocs formed by the high-concentration photosensitive material have extremely high viscosity and are easily entangled into groups. Due to the single molecular structure of the traditional coagulant aid (such as PAM), it is difficult to penetrate its viscous network, resulting in the turbidity of the filtrate still not meeting the standard after centrifugal separation. The above problems make it difficult to efficiently remove the photoresist in the developer waste liquid of the high-order process, seriously affecting the recovery purity and reuse reliability of subsequent TMAH. It is urgent to develop a targeted purification treatment process to improve the removal effect of the photoresist. Summary of the Invention

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

[0006] The purification treatment process for developer waste liquid in a liquid crystal panel factory provided by the present application adopts the following technical solutions: A purification treatment process for developer waste liquid in a liquid crystal panel factory, comprising the following steps: S1. Add a composite acid precipitation solution to the developer waste liquid to adjust the pH to 2.0 - 3.0, stir and react for 2 - 3 h to obtain a suspension, and simultaneously irradiate the developer waste liquid system with ultraviolet light during the stirring reaction process; the composite acid precipitation solution includes a phosphoric acid solution, a trifluoromethanesulfonic acid solution, a demulsifier, and modified β-cyclodextrin; S2. Add an amphiphilic coagulant aid to the suspension, with a dosage of 90 - 100 mg / L. After adding, stir and react for 2 - 3 h, and then let it stand for 3 - 5 h; the amphiphilic coagulant aid is an acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer; S3. Centrifuge the solution system after standing in S2 to obtain a tetramethylammonium salt solution; S4. Fill an acidic cation exchange resin in the acid chamber of a bipolar membrane electrodialysis device, introduce the tetramethylammonium salt solution obtained in S3 into the salt chamber, control the current density at 30 - 50 mA·cm -2 after the bipolar membrane electrodialysis device is powered on, and collect the TMAH solution generated in the alkali chamber.

[0007] By adopting the above technical solutions, due to the combination of phosphoric acid and trifluoromethanesulfonic acid, phosphoric acid provides buffer to stabilize the pH, and trifluoromethanesulfonic acid destroys the ester bonds and ether bonds within the photoresist molecules through its super strong acidity, thereby destroying the hydrophobic stacking structure of the photosensitive material and the resin; thus, it can effectively enhance the acid precipitation rate of the photoresist, which is beneficial to the subsequent full removal of the photoresist in the waste liquid. During the acid precipitation stirring process, on the one hand, ultraviolet light irradiation can break the chemical bonds between the photosensitive material and the resin, thereby effectively destroying the hydrophobic interaction of the colloid, and further being beneficial to improving the acid precipitation rate. On the other hand, ultraviolet light irradiation activates the demulsifier to generate free radicals, which then attack the benzene ring, double bond and other structures of the photoresist through the free radicals, thereby accelerating the demulsification reaction, being beneficial to the full precipitation of the photoresist, and further facilitating the subsequent adsorption and removal. The cationic unit of the amphiphilic coagulant aid neutralizes the colloid charge, the epoxy group forms a covalent bond with the photoresist, and the acrylamide unit adjusts the hydrophilicity, promoting the efficient aggregation of flocs. Finally, through centrifugal separation and ion exchange in the BMEDI device, high-purity purification treatment of TMAH is achieved, effectively enhancing the reliability of TMAH reuse.

[0008] Optionally, the wavelength of the ultraviolet light is 254 - 365 nm, and the power density is 50 - 100 mW / cm².

[0009] By adopting the above technical solution, for the power density of the above ultraviolet light wavelength, the ultraviolet light within the above wavelength range has a relatively high photon energy. Therefore, it can effectively break the chemical bonds between the photosensitive material and the resin, thereby effectively destroying the hydrophobic interaction of the colloid, making the photoresist easy to precipitate, and can effectively excite the breaker to generate free radicals, accelerating the breaking reaction, and further improving the acid precipitation rate of the photoresist.

[0010] Optionally, the mass ratio of the phosphoric acid solution to the trifluoromethanesulfonic acid solution in the composite acid precipitation solution 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; 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.

[0011] Optionally, the mass concentration of the phosphoric acid solution is 23% - 30%; the concentration of the trifluoromethanesulfonic acid solution is 5% - 10%.

[0012] By adopting the above technical solution, the ratio of the above composite acid precipitation solution can not only ensure that the breaker fully exerts its role in cutting the molecular chain of the photoresist, but also can enrich the decomposition products through the modified β-cyclodextrin to prevent their re-polymerization. The concentration settings of 23% - 30% for the phosphoric acid solution and 5% - 10% for the trifluoromethanesulfonic acid solution ensure the balance of the acid strength and buffering capacity during the acid precipitation process.

[0013] Optionally, the modified β-cyclodextrin is prepared by the following method: A1. Dissolve β-cyclodextrin in deionized water, add sodium diethyldithiocarbamate and potassium carbonate, react at 50 - 60 °C for 5 - 6 h under nitrogen protection, and then obtain diethyldithiocarbamate-β-cyclodextrin through cooling and centrifugal separation; A2. Add diethyldithiocarbamate-β-cyclodextrin to DMSO, add cinnamoyl chloride and triethylamine, react at room temperature for 10 - 12 h, and obtain the modified β-cyclodextrin after centrifugation and drying after the reaction.

[0014] By adopting the above technical solution, the above modified β-cyclodextrin is grafted step by step with sodium dithiocarbamate and cinnamoyl chloride to introduce dithiocarbamate groups and cinnamate groups. The dithiocarbamate groups generate sulfur free radicals under ultraviolet light, catalyze the double bond breakage of the photosensitive material, and enhance the recognition of diazoquinone compounds through sulfur-π interaction; the cinnamate groups undergo a cross-linking reaction under ultraviolet light irradiation to form a three-dimensional network structure, fix the captured photoresist fragments, and at the same time, the surface charge is reversed after cross-linking, promoting the electrostatic attraction with negatively charged colloids. Through the above effects, the viscosity of the flocs formed by the precipitated photosensitive material can be reduced, avoiding aggregation into lumps, which is beneficial to subsequent adsorption and removal by a coagulant aid, and further reducing the content of photoresist impurities in the filtrate after centrifugal separation, and is beneficial to improving the purification and removal effect of the photoresist in the waste liquid.

[0015] 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).

[0016] 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).

[0017] Acrylamide, dimethyldiallylammonium chloride, and glycidyl methacrylate are added to deionized water and stirred for 20 - 30 min, then ammonium persulfate is added, and the mixture is stirred and reacted at 60 - 70 °C for 4 - 6 h under nitrogen protection, and then obtained acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer through filtration, washing, and drying.

[0018] By adopting the above technical solution, acrylamide, dimethyldiallylammonium chloride, and glycidyl methacrylate are terpolymerized to form a polymer structure with multiple action mechanisms. The DMDAAC unit provides a 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 group and carboxyl group of the photoresist to form a covalent bond bridge; the AM unit adjusts the hydrophilicity to avoid excessive hydrophobicity of the flocs. The precise dosage control of each monomer and ammonium persulfate maintains the molecular weight of the coagulant aid at 10 5 -10 6 Da, while ensuring the charge neutralization and bridging ability, reducing the solution viscosity. Compared with the traditional PAM coagulant aid, the terpolymer of the present application significantly improves the flocculation effect and solid-liquid separation efficiency of highly viscous flocs, reducing the turbidity of the filtrate after centrifugation to below 10 NTU.

[0019] 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.

[0020] Optionally, the gel breaker is any one of mercaptoethanol and dithiothreitol.

[0021] In summary, this application has the following beneficial effects: 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.

[0022] 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.

[0023] 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 implementation manners

[0024] The present application will be further described in detail below in conjunction with embodiments.

[0025] Preparation examples of modified β-cyclodextrin Preparation example 1 The modified β-cyclodextrin is prepared by the following method: 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, react at 50 °C for 5 h under nitrogen protection, cool to room temperature after the reaction, then carry out centrifugal separation, and dry at 40 °C to obtain dithiocarbamate-β-cyclodextrin; A2. Disperse 10 g of dithiocarbamate-β-cyclodextrin in 50 g of DMSO, add 2 g of cinnamoyl chloride and 1 g of triethylamine, react at room temperature for 10 h, after the reaction, carry out centrifugation and dry at 40 °C to obtain the modified β-cyclodextrin.

[0026] Preparation example 2 The modified β-cyclodextrin is prepared by the following method: 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, react at 55 °C for 5.5 h under nitrogen protection, cool to room temperature after the reaction, then carry out centrifugal separation, and dry at 40 °C to obtain dithiocarbamate-β-cyclodextrin; 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, react at room temperature for 11 h, after the reaction, carry out centrifugation and dry at 40 °C to obtain the modified β-cyclodextrin.

[0027] Preparation example 3 The modified β-cyclodextrin is prepared by the following method: 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, react at 60 °C for 6 h under nitrogen protection, cool to room temperature after the reaction, then carry out centrifugal separation, and dry at 40 °C to obtain dithiocarbamate-β-cyclodextrin; A2. Disperse 10 g of dithiocarbamate-β-cyclodextrin in 70 g of DMSO, add 3 g of cinnamoyl chloride and 2 g of triethylamine, react at room temperature for 12 h, after the reaction, carry out centrifugation and dry at 40 °C to obtain the modified β-cyclodextrin.

[0028] Preparation examples of acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer Preparation example 4 100 g of acrylamide, 80 g of dimethyldiallylammonium chloride, and 30 g of glycidyl methacrylate were added to 700 g of deionized water, stirred for 20 min, then 5.25 g of ammonium persulfate was added, and the mixture was stirred and reacted at 60 °C for 4 h under nitrogen protection. Then, it was filtered, washed, and dried to obtain an acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer.

[0029] Preparation Example 5 100 g of acrylamide, 90 g of dimethyldiallylammonium chloride, and 40 g of glycidyl methacrylate were added to 730 g of deionized water, stirred for 25 min, then 9.2 g of ammonium persulfate was added, and the mixture was stirred and reacted at 65 °C for 5 h under nitrogen protection. Then, it was filtered, washed, and dried to obtain an acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer.

[0030] Preparation Example 6 100 g of acrylamide, 100 g of dimethyldiallylammonium chloride, and 50 g of glycidyl methacrylate were added to 750 g of deionized water, stirred for 30 min, then 12.5 g of ammonium persulfate was added, and the mixture was stirred and reacted at 70 °C for 6 h under nitrogen protection. Then, it was filtered, washed, and dried to obtain an acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer.

[0031] Example Example 1 A purification treatment process for the developing solution waste liquid in a liquid crystal panel factory includes the following steps: S1. Add a composite acid precipitation solution to 10 kg of the developing solution waste liquid to adjust the pH to 2.0, stir and react for 2 h to obtain a suspension. During the stirring reaction process, the developing solution waste liquid system is irradiated with ultraviolet light at the same time. The wavelength of the ultraviolet light is 254 nm, and the power density is 50 mW / cm². The material ratio of the composite acid precipitation solution is shown in Table 1, where the mass concentration of the phosphoric acid solution is 23%; the concentration of the trifluoromethanesulfonic acid solution is 5%; the gel breaker is selected as mercaptoethanol, and the modified β-cyclodextrin is the modified β-cyclodextrin prepared in Preparation Example 1; S2. Add an amphiphilic coagulant aid to the suspension, with a dosage of 90 mg / L. After adding, stir and react for 2 h, and then let it stand for 3 h; the amphiphilic coagulant aid is the acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 4; S3. Centrifuge the solution system after standing in S2 at a speed of 3000 rpm for 30 min to obtain a tetramethylammonium salt solution; S4. Fill the acid chamber of the bipolar membrane electro-deionization device with D001 styrene-based cation exchange resin, introduce the tetramethylammonium salt solution obtained in S3 into the salt chamber, and control the current density to be 30 mA·cm -2 after the bipolar membrane electro-deionization device is powered on, and collect the TMAH solution generated in the alkali chamber.

[0032] Example 2 A purification treatment process for the developer waste liquid in a liquid crystal panel factory, comprising the following steps: S1. Add a composite acid precipitation solution to 10 kg of the developer waste liquid to adjust the pH to 2.5, stir and react for 2.5 h to obtain a suspension, and irradiate the developer waste liquid system with ultraviolet light during the stirring reaction process. The wavelength of the ultraviolet light is 300 nm, and the power density is 80 mW / cm². The material ratio of the composite acid precipitation solution 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 selected as dithiothreitol, and the modified β-cyclodextrin is the modified β-cyclodextrin prepared in Preparation Example 2; S2. Add an amphiphilic coagulant aid to the suspension, with a dosage of 95 mg / L. After adding, stir and react for 2.5 h, and then let it stand for 4 h; the amphiphilic coagulant aid is the acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 4; S3. Centrifuge the solution system after standing in S2 at a speed of 3000 rpm for 30 min to obtain a tetramethylammonium salt solution; S4. Fill the acid chamber of the bipolar membrane electro-deionization device with D001 styrene-based cation exchange resin, introduce the tetramethylammonium salt solution obtained in S3 into the salt chamber, and control the current density to be 40 mA·cm -2 after the bipolar membrane electro-deionization device is powered on, and collect the TMAH solution generated in the alkali chamber.

[0033] Example 3 A purification treatment process for the developer waste liquid in a liquid crystal panel factory, comprising the following steps: S1. Add a composite acid precipitation solution to 10 kg of the developer waste liquid to adjust the pH to 3.0, stir and react for 3 h to obtain a suspension, and irradiate the developer waste liquid system with ultraviolet light during the stirring reaction process. The wavelength of the ultraviolet light is 365 nm, and the power density is 100 mW / cm². The material ratio of the composite acid precipitation solution 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 as mercaptoethanol, and the modified β-cyclodextrin is the modified β-cyclodextrin prepared in Preparation Example 3; S2. Add an amphiphilic coagulant aid to the suspension at a dosage of 10 mg / L. After adding, stir and react for 3 h, and then let it stand for 5 h. The amphiphilic coagulant aid is the acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 4. S3. Centrifuge the solution system after standing in S2 at a speed of 3000 rpm for 30 min to obtain a tetramethylammonium salt solution. S4. Fill the acid chamber of the bipolar membrane electro-deionization device with D001 styrene-based cation exchange resin, and introduce the tetramethylammonium salt solution obtained in S3 into the salt chamber. After the bipolar membrane electro-deionization device is powered on, control the current density to be 50 mA·cm -2 , and collect the TMAH solution generated in the alkali chamber.

[0034] Table 1 Raw materials and ratios (kg) of the composite acid precipitation liquid in Examples 1-3

[0035] Example 4 A purification treatment process for the developer waste liquid in a liquid crystal panel factory, which is different from Example 1 in that the amphiphilic coagulant aid in this example is the acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 5.

[0036] Example 5 A purification treatment process for the developer waste liquid in a liquid crystal panel factory, which is different from Example 1 in that the amphiphilic coagulant aid in this example is the acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer prepared in Preparation Example 6.

[0037] Comparative Example Comparative Example 1 A purification treatment process for the developer waste liquid in a liquid crystal panel factory, including the following steps: S1. Add a hydrochloric acid solution with a mass concentration of 15% to 10 kg of the developer waste liquid to adjust the pH to 2.0, and stir and react for 2 h to obtain a suspension. S2. Add a polyacrylamide coagulant aid to the suspension at a dosage of 90 mg / L. After adding, stir and react for 2 h, and then let it stand for 3 h. S3. Centrifuge the solution system after standing in S2 at a speed of 3000 rpm for 30 min to obtain a tetramethylammonium salt solution. S4. Fill the acid chamber of the bipolar membrane electro-deionization device with D001 styrene-based cation exchange resin, and introduce the tetramethylammonium salt solution obtained in S3 into the salt chamber. After the bipolar membrane electro-deionization device is powered on, control the current density to be 30 mA·cm -2 , and collect the TMAH solution generated in the alkali chamber.

[0038] Comparative Example 2 A purification treatment process for the developer waste liquid in a liquid crystal panel factory. The difference from Example 1 is that in this comparative example, an equal amount of hydrochloric acid solution with a mass concentration of 15% is used to replace the composite acid precipitation liquid in S1, and the operations of the remaining steps are the same as those in Example 1.

[0039] Comparative Example 3 A purification treatment process for the developer waste liquid in a liquid crystal panel factory. The difference from Example 1 is that in this comparative example, ultraviolet light irradiation treatment is not carried out during the acid precipitation stirring reaction in S1, and the operations of the remaining steps are the same as those in Example 1.

[0040] Comparative Example 4 A purification treatment process for the developer waste liquid in a liquid crystal panel factory. The difference from Example 1 is that in this comparative example, polyacrylamide is selected as the coagulant aid in S2, and the operations of the remaining steps are the same as those in Example 1.

[0041] Detection Test 1. Determination of acid precipitation rate The concentrations of photoresist resin and photosensitive material in the waste liquid before and after step S1 are determined by high performance liquid chromatography (HPLC). Chromatographic conditions: C18 column (150mm×4.6mm), mobile phase methanol / water (70:30, v / v), flow rate 1.0mL / min, ultraviolet detector wavelength 254nm. The acid precipitation rate is calculated based on the concentrations of photoresist resin and photosensitive material in the waste liquid before and after step S1, and the detection results are shown in Table 2.

[0042] 2. Determination of the turbidity of the filtrate after centrifugation The turbidity of the filtrate after step S3 is determined by a HACH2100Q turbidimeter, and the detection results are shown in Table 2.

[0043] 3. Residual amount of photoresist in TMAH solution The residual photoresist content in the TMAH solution collected in S4 is detected by ultra high performance liquid chromatography - mass spectrometry (UPLC - MS), and the detection results are shown in Table 2.

[0044] Table 2 Detection Results

[0045] As can be seen from Table 2, in the treatment processes of Examples 1-5 of the present application, the acid precipitation rates after Step S1 all reached over 97.6%. In Comparative Example 1, the traditional single hydrochloric acid treatment only had an acid precipitation rate of 67.4% after Step S1, and that of 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 solution used in the present application can better promote the precipitation of photoresist in the developer waste liquid. By providing a stable pH buffer environment with phosphoric acid to prevent the decomposition of TMAH, trifluoromethanesulfonic acid destroys the ester bonds and ether bonds of the photoresist, and cooperates with ultraviolet light to excite the depolymerizer to accelerate the depolymerization reaction, and activates the sulfur-π interaction of modified β-cyclodextrin to form a "acidolysis-photocatalysis-molecular capture" triple mechanism, completely disintegrating the colloidal stability, thus fully promoting the precipitation of photoresist. In Comparative Example 3, ultraviolet light irradiation treatment was not used, and its acid precipitation rate dropped to 76.7%, proving the key role of ultraviolet light in free radical generation and the crosslinking of modified β-cyclodextrin; modified β-cyclodextrin can promote the further increase of the acid precipitation rate through the photo-responsive characteristics of dithiocarbamate and cinnamate groups.

[0046] The filtrate turbidity of Examples 1-5 was all <8.3 NTU. In Comparative Example 1, the traditional PAM coagulant aid was used, and the filtrate turbidity after centrifugation reached 156 NTU. In Comparative Example 4, when PAM was used to replace the amphiphilic coagulant aid, the turbidity was still as high as 164 NTU. This shows that the amphiphilic coagulant aid of the present application has a good flocculation and adsorption effect.

[0047] The photoresist residue in the TMAH solution of Examples 1-5 was <5.4 ppm, while that in Comparative Example 1 was as high as 73.2 ppm. This shows that the treatment process of the present application has a good purification and removal effect on the photoresist in the developer waste liquid. First, more than 95% of the organic matter is removed through composite acid precipitation combined with ultraviolet light irradiation treatment and centrifugal separation. In the BMEDI device, the D001 type cation exchange resin combines with a current density of 30-50 mA·cm⁻². Through the dual effects of electro-migration and ion exchange, the tetramethylammonium ions are efficiently migrated to the alkali chamber, and at the same time, the resin in the acid chamber adsorbs the residual impurities to ensure the purity of TMAH, which is beneficial to enhancing the reuse reliability of TMAH.

[0048] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions 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 treatment process for the developer waste liquid in a liquid crystal panel factory, characterized in that, It includes the following steps: S1. Add a composite acid precipitation solution to the developer waste liquid to adjust the pH to 2.0 - 3.0, stir and react for 2 - 3 h to obtain a suspension, and irradiate the developer waste liquid system with ultraviolet light during the stirring reaction process; the composite acid precipitation solution includes a phosphoric acid solution, a trifluoromethanesulfonic acid solution, a gel breaker, and modified β-cyclodextrin; S2. Add an amphiphilic coagulant aid to the suspension, with a dosage of 90 - 100 mg / L. After adding, stir and react for 2 - 3 h, and then let it stand for 3 - 5 h; the amphiphilic coagulant aid is an acrylamide-dimethyldiallylammonium chloride-glycidyl methacrylate terpolymer; S3. Centrifuge the solution system after standing in S2 to obtain a tetramethylammonium salt solution; S4. Fill the acid chamber of the bipolar membrane electro-deionization device with acidic cation exchange resin, introduce the tetramethylammonium salt solution obtained in S3 into the salt chamber, and control the current density to be 30 - 50 mA·cm after the bipolar membrane electro-deionization device is powered on. -2 Then collect the TMAH solution generated in the alkali chamber.

2. The purification treatment process for the developer waste liquid in a liquid crystal panel factory according to claim 1, wherein: The wavelength of the ultraviolet light is 254 - 365 nm, and the power density is 50 - 100 mW / cm².

3. The purification treatment process for the developer waste liquid in a liquid crystal panel factory according to claim 1, wherein: In the composite acid precipitation solution, the mass ratio of the phosphoric acid solution to the trifluoromethanesulfonic acid solution 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; 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. A purification treatment process for the developer waste 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 treatment process for the developer waste liquid in a liquid crystal panel factory according to claim 1, wherein: The modified β-cyclodextrin is prepared by the following method: A1. Dissolve β-cyclodextrin in deionized water, add sodium diethyldithiocarbamate and potassium carbonate, react at 50 - 60 °C for 5 - 6 h under nitrogen protection, and then obtain diethyldithiocarbamate-β-cyclodextrin through cooling and centrifugation; A2. Add diethyldithiocarbamate-β-cyclodextrin to DMSO, add cinnamoyl chloride and triethylamine, react at room temperature for 10 - 12 h, and obtain modified β-cyclodextrin through centrifugation and drying after the reaction ends.

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

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

8. A purification treatment process for the developing solution waste liquid in a liquid crystal panel factory according to claim 1, characterized in that, ​ ​ 9. A purification treatment process for the developing solution waste liquid in a liquid crystal panel factory according to claim 8, characterized in that, ​ 10. A purification treatment process for the developer waste liquid in a liquid crystal panel factory according to claim 1, characterized in that, ​

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