Organic matter fractionation controlled method and system for co-production of acid and base from epoxy resin wastewater

Abstract

This invention relates to the field of industrial wastewater treatment and resource utilization technology, and particularly to a method and system for the co-production of acid and alkali from epoxy resin wastewater with graded control of organic matter. The method includes the following steps: Fourier transform ion cyclotron resonance mass spectrometry is used to analyze the molecular composition of organic matter in the epoxy resin wastewater; organic matter is classified into categories A, B, and C based on oxygen-to-carbon ratio, hydrogen-to-carbon ratio, and molecular weight, and graded control targets are set; the wastewater is then introduced into a multi-stage electrodialysis system, and the organic matter is retained in stages through gradient operating conditions; total organic carbon and fluorescence spectral characteristics are monitored during electrodialysis. This invention achieves synergistic inhibition of organic matter during electrodialysis-bipolar membrane electrodialysis through molecular feature analysis and graded control, resulting in high-purity acid and alkali products. It has advantages such as high resource recovery efficiency and no secondary pollution, and is suitable for the deep treatment and resource utilization of epoxy resin production wastewater with high salt and high organic matter content.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment and resource utilization technology, and in particular to a method and system for the co-production of acid and alkali in epoxy resin wastewater with graded control of organic matter. Background Technology

[0002] Epoxy resin is an important thermosetting resin widely used in coatings, electronic packaging, composite materials, and other fields. During its production, the condensation reaction between bisphenol A and epichlorohydrin generates a large amount of high-salt, high-organic wastewater; approximately 1.5 tons of wastewater are produced for every ton of epoxy resin produced. This type of wastewater is characterized by high sodium chloride content (10-20 wt%), complex organic composition (TOC 5000-7000 mg / L), stable physicochemical properties, and difficulty in biodegradation, posing a key bottleneck to the sustainable development of the industry.

[0003] Existing treatment technologies mainly suffer from the following problems: 1. The dilution biochemical method has high treatment costs and large land area requirements, and it is difficult to completely treat organic matter and inorganic salts; 2. The multi-effect evaporation method requires repeated acid adjustment and neutralization, consumes a large amount of sodium hydroxide and hydrochloric acid, generates hazardous iron sludge, and has high post-treatment costs; 3. The advanced oxidation method consumes a large amount of oxidant, has high treatment costs, and cannot effectively recover sodium chloride. In epoxy resin wastewater, there is a lack of effective removal technology for refractory organic matter in high-salt environments, resulting in a large amount of inorganic salts becoming difficult-to-treat industrial waste salts due to the mixing of organic matter, and thus failing to form usable resources.

[0004] Electrodialysis (ED), as an electrically driven membrane separation technology, has been used in recent years to treat epoxy resin wastewater. Its purpose is to desalinate the wastewater and remove organic matter. However, it still faces the following key problems: First, the problem of residual organic matter after electrodialysis desalination. For example, patent documents CN108341536A entitled "A Method for Treating Epoxy Resin Production Wastewater" and CN117534228A entitled "A Method for Recycling and Treating Epoxy Resin Production Wastewater" both use electrodialysis for desalination, but the resulting salt solution still contains a large amount of organic matter. It needs to be further treated by Fenton oxidation or ozone / ultraviolet catalytic oxidation, which increases the cost of reagents and the complexity of the process, and is prone to introducing secondary pollution. II. Technical shortcomings of direct treatment by bipolar membrane electrodialysis (BMED). For example, a patent document published in CN111592167A entitled "A method for treating high-salt epoxy resin wastewater" uses bipolar membrane electrodialysis to convert salts into acids and bases. However, its pretreatment (azeotropic alkaline hydrolysis and neutralization) mainly targets specific organic compounds (toluene, monochloropropanediol), which cannot effectively control the migration of organic compounds in the wastewater. This results in residual organic compounds in the acid and base products, affecting the purity of the products. Therefore, when electrodialysis separates inorganic salts and organic compounds in epoxy resin wastewater, there is a lack of a method that can effectively control the migration of organic compounds and solve the problem of low purity salt products in resource utilization.

[0005] In summary, there is an urgent need to develop a wastewater treatment method that can be hierarchically controlled based on the characteristics of organic molecules, in order to overcome the technical bottlenecks in high-purity salt recovery and acid-alkali co-production. This has significant industrial application value and technological innovation significance for realizing the green transformation of the epoxy resin industry. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method and system for graded control of organic matter in epoxy resin wastewater acid-base co-production. By analyzing the migration mechanism of organic matter at the molecular level, a graded control strategy is established to synergistically inhibit organic matter migration during multi-stage electrodialysis and bipolar membrane electrodialysis, thereby achieving high-purity sodium chloride recovery and acid-base co-production.

[0007] The technical problem solved by this invention is achieved by the following technical solution: A method for co-producing acid and alkali from epoxy resin wastewater with graded control of organic matter includes the following steps: S1: Analysis of Organic Molecular Characteristics and Establishment of Hierarchical Control Strategies Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to analyze the molecular composition of organic matter in epoxy resin wastewater. Based on the oxygen / carbon ratio (O / C), hydrogen / carbon ratio (H / C), and molecular weight, the organic matter was classified into three categories: A, B, and C. Classification control targets were set: Category A organic matter had an O / C ratio ≥ 0.5, a H / C ratio ≥ 1.0, and a molecular weight ≤ 300 Da; Category B organic matter had an O / C ratio of 0.2-0.5, a H / C ratio of 0.5-1.0, and a molecular weight of 300-600 Da; and Category C organic matter had an O / C ratio < 0.2, a H / C ratio < 0.5, and a molecular weight > 600 Da. The classification control targets were: migration rate of Category A organic matter ≤ 5%, migration rate of Category B organic matter ≤ 3%, and migration rate of Category C organic matter ≤ 1%. S2: Multi-stage electrodialysis for segmented organic matter removal Wastewater is fed into a multi-stage electrodialysis system, where organic matter is retained in stages through gradient operating conditions. S3: Organic Matter Migration Monitoring and Dynamic Regulation During electrodialysis, total organic carbon (TOC) and fluorescence spectral characteristics are monitored, and operating parameters are adjusted when the organic matter mobility exceeds the graded control target. S4: Bipolar membrane electrodialysis for acid-base co-production and synergistic control of organic matter The concentrated electrodialysis solution is passed into a bipolar membrane electrodialysis system. Based on the molecular characteristics of the residual organic matter, a pH regulation or voltage regulation strategy is selected to inhibit the migration of organic matter and co-produce hydrochloric acid and sodium hydroxide. Preferably, the multi-stage electrodialysis system in S2 is a two-stage electrodialysis system. The first stage applies a voltage of 7-9V, a flow rate of 0.6-0.8L / min, and a running time of 60-90 minutes. The second stage applies a voltage of 9-11V, a flow rate of 0.8-1.0 L / min, and a running time of 90-120 minutes.

[0008] Preferably, the operating parameter adjustment in S3 is selected from one or more of the following: reducing the applied voltage by 0.5-1V, increasing the flow rate by 0.1-0.2 L / min, and adjusting the pH of the dilute chamber to 6.5-7.0.

[0009] Preferably, in step S4, the bipolar membrane electrodialysis applies a voltage of 16-20V, a membrane surface flow rate of 12-16 cm / s, and a running time of 60-90 minutes.

[0010] Preferably, the control strategy selected in S4 based on the molecular characteristics of the residual organic matter is as follows: when the proportion of type A in the residual organic matter is >60%, the pH of the feed liquid is adjusted to 6.0-7.0; when the proportion of type B in the residual organic matter is >40%, the applied voltage is reduced to 14-16V.

[0011] Preferably, the process also includes a membrane cleaning step: after 5-10 cycles of electrodialysis and bipolar membrane electrodialysis, the membrane module is cleaned alternately for 30-60 minutes with a 0.5-1.0 wt% hydrochloric acid solution and a 0.5-1.0 wt% sodium hydroxide solution.

[0012] This invention also provides a treatment system for a method of co-producing acid and alkali in epoxy resin wastewater for implementing graded control of organic matter, characterized in that it comprises: A multi-stage electrodialysis unit includes a first-stage electrodialysis unit and a second-stage electrodialysis unit connected in series with the first-stage electrodialysis unit, wherein the concentrate outlet of the second-stage electrodialysis unit is the total concentrate outlet of the multi-stage electrodialysis unit. The process monitoring unit includes a total organic carbon analyzer and a three-dimensional fluorescence spectrometer. The detection end of the process monitoring unit is connected to the dilute and concentrated chambers of the multi-stage electrodialysis unit for online detection of total organic carbon and fluorescence spectral characteristics. The bipolar membrane electrodialysis unit adopts a three-chamber structure design, and the feed inlet is connected to the total concentrate outlet of the multi-stage electrodialysis unit; The pH and TOC online monitoring and control unit has its detection end connected to the feed end of the bipolar membrane electrodialysis unit, its control execution end interlocked with the feed pump of the bipolar membrane electrodialysis unit, and establishes a signal connection with the process monitoring unit.

[0013] Furthermore, the present invention also relates to the application of the above-mentioned methods or systems in the treatment and resource recovery of epoxy resin production wastewater.

[0014] The beneficial effects of this invention are: A pioneering organic matter classification and control strategy based on molecular characteristics: Unlike existing technologies that treat organic matter as a whole, this invention introduces FT-ICR MS molecular characterization technology into process design for the first time. Organic matter is accurately classified according to molecular characteristics such as oxygen-carbon ratio and hydrogen-carbon ratio, and differentiated migration rate control targets are set. This solves the problem of unpredictable and uncontrollable behavior of complex organic matter in membrane separation process from the source. Multi-stage electrodialysis achieves segmented retention of organic matter: By designing gradient operating conditions for two-stage electrodialysis, and utilizing the differentiated retention performance of ion exchange membranes for organic matter under different electric field strengths and flow rates, segmented retention of Class C hydrophobic macromolecules, Class B medium-molecular-weight oxygen-containing organic matter, and Class A small-molecular-weight polar organic matter is achieved sequentially. Compared to single electrodialysis or direct bipolar membrane treatment, this invention significantly reduces the organic matter load entering subsequent stages. Synergistic Control of Organic Matter through ED-BMED Coupling: This invention constructs a complete organic matter migration inhibition system, ranging from "electrodialysis hierarchical control" to "bipolar membrane electrodialysis synergistic control." In particular, it intelligently selects pH or voltage regulation strategies based on the molecular characteristics of residual organic matter (the proportion of type A or type B), unlike existing technologies that rely solely on pH or temperature adjustment. This achieves more precise inhibition of organic matter electromigration behavior. Comparative studies show that the TOC content of acid-base products without synergistic control is 2-3 times higher than that of products using this invention. High resource recovery efficiency and product purity: The method of this invention can achieve a sodium chloride recovery rate of >95%, and the co-produced hydrochloric acid and sodium hydroxide have high concentrations (up to 1.5 mol / L or more) and extremely low TOC content. They can be directly reused in the epoxy resin production process, realizing the high-value utilization of salt in wastewater, and have good economic benefits and industrial application prospects. Environmentally friendly and free of secondary pollution: The entire treatment process is a physicochemical process that does not introduce metal ions such as iron salts, and does not generate hazardous waste such as iron sludge. It avoids the environmental risks of traditional advanced oxidation or evaporation processes and meets the requirements of green chemical development. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 The process flow diagram provided for this invention; Figure 2 This is a system block diagram provided for the present invention.

[0017] In the diagram, 1 is the multi-stage electrodialysis unit; 11 is the first-stage electrodialysis unit; 12 is the second-stage electrodialysis unit; 2 is the process monitoring unit; 21 is the total organic carbon analyzer; 22 is the three-dimensional fluorescence spectrometer; 3 is the bipolar membrane electrodialysis unit; and 4 is the pH and TOC online monitoring and control unit. Detailed Implementation

[0018] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations. Example

[0019] This embodiment provides a method for the co-production of acid and alkali in epoxy resin wastewater with graded control of organic matter, specifically including the following steps: 1. Analysis of the molecular characteristics of organic compounds Wastewater samples were taken from an epoxy resin production plant. The water quality parameters were: conductivity 243 mS / cm, total organic carbon (TOC) 5930 mg / L, Na⁺ concentration 123225 mg / L, Cl⁻ concentration 193120 mg / L, pH 12.7. Fourier transform ion cyclotron resonance mass spectrometry was used to analyze the molecular composition of the organic matter in the wastewater. The results are as follows: (1) Class A organic compounds (O / C≥0.5, molecular weight≤300 Da): accounting for about 45%, mainly glycerol, propylene glycol, monochloropropanediol, etc.; (2) Class B organic compounds (0.2≤O / C<0.5, 300 Da<molecular weight≤600 Da): accounting for about 35%, mainly epichlorohydrin hydrolysis products, oligomer fragments, etc.; (3) Class C organic compounds (O / C<0.2, molecular weight>600 Da): accounting for about 20%, mainly unpolymerized epoxy resin oligomers.

[0020] Based on the analysis results, the following graded control targets were set: migration rate of Class A organic matter ≤5%, migration rate of Class B organic matter ≤3%, and migration rate of Class C organic matter ≤1%.

[0021] 2. Multi-stage electrodialysis with segmented retention The wastewater was passed through a first-stage electrodialysis system at an applied voltage of 8V and a flow rate of 0.7 L / min for 75 minutes. After treatment, the TOC concentration in the concentrate chamber was 285 mg / L, and the migration rate of Class A organic matter was 4.8%, achieving the graded control target.

[0022] The concentrate from the first-stage electrodialysis chamber was passed into the second-stage electrodialysis chamber at a voltage of 10V and a flow rate of 0.9 L / min for 105 minutes. After treatment, the TOC concentration in the concentrate chamber was 97 mg / L, and the total organic matter migration rate was 1.6%, with Class A migration rate of 1.2%, Class B migration rate of 0.3%, and Class C migration rate of 0.1%, all meeting the graded control targets. The resulting sodium chloride concentrate had a concentration of 198 g / L.

[0023] 3. Bipolar membrane electrodialysis acid-base co-production and synergistic control The above-mentioned sodium chloride concentrate was passed into a three-compartment bipolar membrane electrodialysis system. A voltage of 18V and a membrane surface flow rate of 14.5 cm / s were applied, and the system was run for 75 minutes. According to FT-ICR MS analysis, the proportion of type A in the residual organic matter was approximately 72%. A pH control strategy was adopted to adjust the pH of the feed solution to 6.5 to inhibit the electromigration of organic matter.

[0024] After the treatment, the acid chamber yielded a hydrochloric acid solution with a concentration of 1.57 mol / L and a TOC of 5.1 mg / L; the alkali chamber yielded a sodium hydroxide solution with a concentration of 1.52 mol / L and a TOC of 3.3 mg / L.

[0025] 4. Effectiveness Evaluation According to calculations, this embodiment can recover approximately 181 kg of sodium chloride, approximately 57 kg of hydrochloric acid (calculated as HCl), and approximately 49 kg of sodium hydroxide from 1 cubic meter of wastewater. After deducting operating costs, the comprehensive benefit is 68.9 yuan / m³ of wastewater, demonstrating good economic and environmental benefits. Example

[0026] This embodiment is the same as Embodiment 1, except that the operating parameters and control strategies in steps 2 and 3 are different.

[0027] 1. Analysis of the molecular characteristics of organic compounds Same as Example 1.

[0028] 2. Multi-stage electrodialysis with segmented retention The first stage of electrodialysis was performed at a voltage of 7V and a flow rate of 0.6 L / min for 90 minutes; the second stage was performed at a voltage of 9V and a flow rate of 0.8 L / min for 120 minutes. After treatment, the TOC concentration in the concentrate chamber was 92 mg / L, and the total organic matter migration rate was 1.5%, meeting the staged control target. The concentration of the sodium chloride concentrate was 195 g / L.

[0029] 3. Bipolar membrane electrodialysis acid-base co-production and synergistic control A voltage of 16V and a flow rate of 12 cm / s were applied, and the treatment lasted for 90 minutes. Based on the molecular characteristics of the residual organic matter, type B accounted for approximately 45%, and a voltage control strategy was adopted to reduce the applied voltage to 14V. After treatment, the concentration of hydrochloric acid in the acid chamber was 1.58 mol / L, and the TOC was 3.2 mg / L; the concentration of sodium hydroxide in the alkali chamber was 1.55 mol / L, and the TOC was 2.1 mg / L.

[0030] Comparative Example 1 (No hierarchical control strategy) This comparative example is basically the same as Example 1, except that the organic molecular characteristic analysis and hierarchical control target setting in step 1 are not performed, and the wastewater is directly introduced into the electrodialysis system.

[0031] 1. Electrodialysis treatment Wastewater was directly fed into a single-stage electrodialysis system, with an applied voltage of 9V and a flow rate of 0.8 L / min, and operated for 120 minutes. After treatment, the TOC concentration in the concentrate chamber was 1085 mg / L, the total organic matter migration rate was 18.3%, and the concentration of the resulting sodium chloride concentrate was 152 g / L.

[0032] 2. Bipolar membrane electrodialysis The concentrated solution was passed into a bipolar membrane electrodialysis system with an applied voltage of 18V and a membrane surface flow rate of 14.5 cm / s for 75 minutes without pH or voltage adjustment. After treatment, the concentration of hydrochloric acid in the acid chamber was 1.18 mol / L and the TOC was 389.6 mg / L; the concentration of sodium hydroxide in the alkali chamber was 1.03 mol / L and the TOC was 356.3 mg / L.

[0033] Results analysis: Compared with Example 1, Comparative Example 1 did not adopt a graded control strategy, which led to a significant increase in the migration rate of organic matter in the electrodialysis concentration chamber, resulting in a significantly higher TOC content in the bipolar membrane electrodialysis acid-base products, thus proving the effectiveness of the organic matter graded control strategy of the present invention.

[0034] Comparative Example 2 (without ED-BMED synergistic regulation) This comparative example is basically the same as Example 1, except that the pH or voltage is not adjusted according to the molecular characteristics of residual organic matter during the bipolar membrane electrodialysis stage. 1. Analysis of the molecular characteristics of organic compounds Example

[0035] 2. Multi-stage electrodialysis with segmented retention Example

[0036] 3. Bipolar membrane electrodialysis (without synergistic regulation) The sodium chloride concentrate obtained in step 2 of Example 1 was passed into a bipolar membrane electrodialysis system. A voltage of 18V was applied, the flow rate at the membrane surface was 14.5 cm / s, and the system was run for 75 minutes without pH or voltage adjustment. After the treatment, the concentration of hydrochloric acid in the acid chamber was 1.53 mol / L and the TOC was 28.4 mg / L; the concentration of sodium hydroxide in the alkali chamber was 1.50 mol / L and the TOC was 25.2 mg / L.

[0037] Results analysis: The TOC content of the acid-base product in Comparative Example 2 was significantly higher than that in Example 1, indicating that the strategy of pH or voltage synergistic regulation based on the molecular characteristics of residual organic matter in this invention can effectively inhibit the electromigration of organic matter and improve the purity of acid-base products.

[0038] Membrane cleaning and operational stability In the above embodiments and comparative examples, after every 6 cycles of operation of the electrodialysis and bipolar membrane electrodialysis systems, the membrane modules were alternately cleaned for 45 minutes with 0.8 wt% hydrochloric acid solution and 0.8 wt% sodium hydroxide solution. After cleaning, the membrane flux recovery rate was above 95%, and the system operation was stable.

[0039] The above examples and comparative examples demonstrate that the method for co-production of acid and alkali in epoxy resin wastewater based on the graded control of organic matter provided by the present invention can effectively inhibit the migration of organic matter and achieve high-purity salt recovery and co-production of acid and alkali through molecular characteristic analysis, multi-stage electrodialysis segmented retention and ED-BMED synergistic regulation, which has significant technical advantages and prospects for industrial application.

[0040] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for co-producing acid and alkali from epoxy resin wastewater through graded control of organic matter, characterized in that, Includes the following steps: S1: Fourier transform ion cyclotron resonance mass spectrometry was used to analyze the molecular composition of organic matter in epoxy resin wastewater. Based on the oxygen-carbon ratio, hydrogen-carbon ratio, and molecular weight, the organic matter was divided into Class A, Class B, and Class C, and graded control targets were set. S2: Wastewater is fed into a multi-stage electrodialysis system, and organic matter is retained in stages through gradient operating conditions; S3: Monitor total organic carbon and fluorescence spectral characteristics during electrodialysis, and adjust operating parameters when the organic matter mobility exceeds the graded control target; S4: The concentrated electrodialysis solution is passed into the bipolar membrane electrodialysis system. Based on the molecular characteristics of the residual organic matter, a pH control or voltage control strategy is selected to inhibit the migration of organic matter and to co-produce hydrochloric acid and sodium hydroxide.

2. The method for co-production of acid and alkali in epoxy resin wastewater with graded control of organic matter according to claim 1, characterized in that, In S1, the oxygen-to-carbon ratio of type A organic compounds is ≥0.5, the hydrogen-to-carbon ratio is ≥1.0, and the molecular weight is ≤300 Da; the oxygen-to-carbon ratio of type B organic compounds is 0.2-0.5, the hydrogen-to-carbon ratio is 0.5-1.0, and the molecular weight is 300-600 Da; and the oxygen-to-carbon ratio of type C organic compounds is <0.2, the hydrogen-to-carbon ratio is <0.5, and the molecular weight is >600 Da.

3. The method for co-production of acid and alkali in epoxy resin wastewater with graded control of organic matter according to claim 1, characterized in that, The graded control targets in S1 are: migration rate of Class A organic matter ≤5%, migration rate of Class B organic matter ≤3%, and migration rate of Class C organic matter ≤1%.

4. The method for co-producing acid and alkali in epoxy resin wastewater with graded control of organic matter according to claim 1, characterized in that, The S2 multi-stage electrodialysis system consists of two stages. The first stage applies a voltage of 7-9V, a flow rate of 0.6-0.8 L / min, and a running time of 60-90 minutes. The second stage applies a voltage of 9-11V, a flow rate of 0.8-1.0 L / min, and a running time of 90-120 minutes.

5. The method for co-producing acid and alkali in epoxy resin wastewater with graded control of organic matter according to claim 1, characterized in that, The operating parameters in S3 can be adjusted by one or more of the following: reducing the applied voltage by 0.5-1V, increasing the flow rate by 0.1-0.2 L / min, and adjusting the pH of the dilute chamber to 6.5-7.

0.

6. The method for co-producing acid and alkali in epoxy resin wastewater with graded control of organic matter according to claim 1, characterized in that, In S4, the bipolar membrane electrodialysis is performed with an applied voltage of 16-20V, a membrane surface flow rate of 12-16 cm / s, and a running time of 60-90 minutes.

7. The method for co-producing acid and alkali in epoxy resin wastewater with graded control of organic matter according to claim 1, characterized in that, In step S4, the control strategy selected based on the molecular characteristics of the residual organic matter is as follows: when the proportion of type A in the residual organic matter is >60%, the pH of the feed solution is adjusted to 6.0-7.0; when the proportion of type B in the residual organic matter is >40%, the applied voltage is reduced to 14-16V.

8. The method for co-producing acid and alkali in epoxy resin wastewater with graded control of organic matter according to claim 1, characterized in that, It also includes a membrane cleaning step. After 5-10 cycles of electrodialysis and bipolar membrane electrodialysis, the membrane module is cleaned alternately with 0.5-1.0 wt% hydrochloric acid solution and 0.5-1.0 wt% sodium hydroxide solution for 30-60 minutes.

9. A treatment system for implementing the method for graded control of organic matter in epoxy resin wastewater co-production according to any one of claims 1-8, characterized in that, include: The multi-stage electrodialysis unit (1) includes a first-stage electrodialyzer (11) and a second-stage electrodialyzer (12) connected in series with the first-stage electrodialyzer (11). The concentrate outlet of the second-stage electrodialyzer (12) is the total concentrate outlet of the multi-stage electrodialysis unit (1). The process monitoring unit (2) includes a total organic carbon analyzer (21) and a three-dimensional fluorescence spectrometer (22). The detection end of the process monitoring unit (2) is connected to the dilute and concentrated chambers of the multi-stage electrodialysis unit (1) for online detection of total organic carbon and fluorescence spectral characteristics. The bipolar membrane electrodialysis unit (3) adopts a three-chamber structure design, and the feed inlet is connected to the total concentrate outlet of the multi-stage electrodialysis unit (1); The pH and TOC online monitoring and control unit (4) has its detection end connected to the feed end of the bipolar membrane electrodialysis unit (3), its control execution end is interlocked with the feed pump of the bipolar membrane electrodialysis unit (3), and it establishes a signal connection with the process monitoring unit (2).

10. The method for graded control of organic matter in epoxy resin wastewater co-production according to any one of claims 1-8, or the treatment system according to claim 9, is applied to the treatment and resource recovery of epoxy resin production wastewater.

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