Wastewater treatment method for removing electron-rich organic matter pollution by introducing iron anode

Abstract

A wastewater treatment method for removing electron-rich organic matter pollution by introducing an iron anode comprises the steps that a three-electrode treatment system is constructed, the three-electrode treatment system comprises two anodes and a cathode, the two anodes are distributed on the two sides of the cathode, one anode is a titanium-based PbO2 functional anode, and the other anode is an iron anode; the three-electrode treatment system is used for treating wastewater containing electron donor organic matters, the current density of the titanium-based PbO2 functional anode is controlled to be 20-40 mA / cm < 2 >, the content of chloride ions in the wastewater is controlled to be 4-8 g / L, and the pH value is controlled to be 6-8; the treatment time is 2-5 hours. Compared with a traditional electrooxidation process, the three-electrode treatment system water treatment method can more efficiently remove and purify high-concentration refractory organic pollutants, and is not influenced by background matrix ions in water.

Description

Technical Field

[0001] This invention belongs to the field of organic wastewater treatment technology, and relates to the treatment of highly conductive (high-salt) and difficult-to-degrade industrial organic wastewater, and particularly to a wastewater treatment method that introduces an iron anode to remove electron-rich organic pollutants. Background Technology

[0002] High-salinity organic wastewater treatment is a major challenge for the water treatment industry, while antibiotics are also an emerging pollutant that urgently needs to be treated. Advanced oxidation processes (AOs) are considered an effective way to treat recalcitrant organic wastewater because they can achieve efficient degradation and mineralization of pollutants through reactive oxygen species. However, free radical-mediated AO technologies, such as electrochemical oxidation (EO), while promising, generally face bottlenecks such as high energy consumption, susceptibility to water quality interference, and the potential generation of toxic byproducts. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a wastewater treatment method that introduces an iron anode to remove electron-rich organic pollutants, so as to achieve efficient, low-consumption and adaptable electrochemical treatment of complex water quality with high salinity (high conductivity).

[0004] Given the limitations of existing electrochemical cathode-mediated advanced radical oxidation systems due to oxygen solubility in water and the difficulty in preparing efficient catalysts and activators, addressing the issue from the anode perspective remains a wise choice. This invention proposes introducing a second anode into the traditional titanium-based PbO2-DSA (shape-stable anode) two-electrode electro-oxidation system, forming a three-electrode treatment system of Fe / DSA dual anode and shared cathode, to achieve synergistic effects of multiple mechanisms including electro-oxidation, flocculation, and flotation. This concept not only leverages the highly efficient oxidative degradation capabilities of electro-oxidation but also utilizes the dissolution of the iron anode to further generate Fe(OH)3 flocs for adsorption / flocculation, while simultaneously utilizing the flotation effect triggered by the hydrogen evolution reaction at the shared cathode to further enhance pollutant removal efficiency. Furthermore, addressing the issue of high cost of noble metal oxides and boron-doped diamond (BDD) anode materials, which limit their engineering applications, this invention selects the lower-cost, high-oxygen-evolution-potential PbO2-DSA electrode as the functional anode. This electrode can not only generate HO• but also catalyze the reaction of Cl in solution. - The system generates active chlorine, which then reacts with iron ions dissolved from the iron anode to form high-valence iron, demonstrating its potential to generate Fe(VI) in chlorine-containing systems. This system achieves efficient degradation while simultaneously suppressing the formation of toxic chlorination byproducts through reaction pathway regulation, providing a novel and reliable technical approach for the low-consumption and high-efficiency treatment of high-salt, recalcitrant organic wastewater.

[0005] This invention focuses on constructing a novel electrochemical oxidation system by utilizing electrode structure design and reaction process control to improve the removal efficiency of pollutants such as high-salt organic wastewater and recalcitrant antibiotics, providing a reliable solution for practical engineering applications. For improving the efficiency and reducing power consumption of various electrochemical water treatment processes such as EO, in addition to developing superior electrode materials, the focus can be on the configuration of the electrolysis system. This fully utilizes all cathode and anodic electrode reactions within the system to achieve synergistic effects of multiple removal mechanisms, ensuring that the electrical energy flowing through the system is "effective" at each electrode. This overcomes the limitation of EO relying solely on direct or indirect oxidation at the anode to remove recalcitrant organic pollutants. This configuration and material are suitable for formulation and full utilization in chlorine-containing media. In situ electrochemical generation of high-valence iron species Fe(VI) at the DSA anode, which has a high oxidation potential (E0 = +2.20V vs. SHE), its oxidizing power is stronger than common oxidants such as ozone, chlorine, and hydrogen peroxide. It can selectively attack the electron-rich structures in organic matter via a non-radical pathway, thereby improving degradation efficiency. Simultaneously, the hydroxyl radical pathway of PbO2 electrooxidation degrades organic pollutants, constituting a synergistic effect of free radicals and non-radicals. In addition, the final steady-state product of high-priced iron is Fe. 3+ The generated Fe(OH)3 flocs help the system to exert a synergistic effect of "oxidation + flocculation", thereby achieving efficient removal of organic pollutants.

[0006] Based on this, the technical solution adopted by the present invention is: A wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode includes: A three-electrode processing system is constructed, comprising two anodes and one cathode. The two anodes are distributed on both sides of the cathode, one anode being a titanium-based PbO2 functional anode and the other anode being an iron anode. The three-electrode treatment system was used to treat wastewater containing electron-donating organic matter, with the current density of the titanium-based PbO2 functional anode controlled at 20-40 mA / cm². 2 The chloride ion content in the wastewater is controlled at 4-8 g / L, and the pH value is controlled at 6-8; the treatment time is 2-5 h.

[0007] In one embodiment, the cathode is stainless steel, graphite carbon, or nickel-plated carbon steel; the iron anode is pure iron plate or low-carbon steel.

[0008] In one embodiment, the distance between the cathode and anode in the three-electrode processing system is controlled to be 1.5-3 cm; the dimensions of the titanium-based PbO2 functional anode and cathode are kept the same, the area of ​​the iron anode is 1 to 1 / 6 of the area of ​​the titanium-based PbO2 functional anode, the allowable area of ​​the iron anode is reduced, and the current density is increased accordingly.

[0009] In one embodiment, the iron anode is connected in parallel with a titanium-based PbO2 functional anode, or operates as an inductive electrode.

[0010] In one embodiment, the three-electrode processing system is powered by either direct current or pulsed current without negative current.

[0011] In one embodiment, the electron-rich organic compound includes one or more of sulfamethoxazole (SMX), norfloxacin (NOR), and ciprofloxacin (CIP). Such organic compounds refer to molecules containing a large number of electron-donating groups, mainly including one or more of hydroxyl-OH, amino-NH2, and alkoxy-OR.

[0012] In one embodiment, the three-electrode processing system is provided in multiple groups, each group including the two anodes and one cathode, thereby achieving the scalability of the present invention.

[0013] In one embodiment, the current density of the titanium-based PbO2 functional anode is 30 mA / cm². 2 When the chloride ion concentration in the wastewater is 6000 mg / L and the pH value is 7, the treatment efficiency for sulfamethoxazole (SMX) is 89.28%, and the energy consumption is 7.25 kWh / m³. 3 The COD removal rate was 60.14%, the TOC removal rate was 55.72%, the degradation rate of norfloxacin (NOR) was 95.97%, the degradation rate of ciprofloxacin (CIP) was 96.34%, the degradation rate of ibuprofen (IBU) was 89.62%, and the degradation rate of phenol (Phenol) was 90.39%.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. Compared with traditional electro-oxidation processes, the three-electrode treatment system water treatment method of the present invention can remove and purify high-concentration recalcitrant organic pollutants more efficiently, and is not affected by background matrix ions in the water.

[0015] 2. In the constructed three-electrode electro-oxidation system, two anodes are used to fully utilize the shared cathode. On the one hand, this fully leverages the efficient oxidative degradation capacity of electro-oxidation; on the other hand, the Fe(OH)3 flocs generated by the electrochemical dissolution of the iron anode exert an adsorption / flocculation effect. Simultaneously, the flotation effect triggered by the hydrogen evolution reaction at the shared cathode further enhances the removal efficiency of pollutants. Under the preferred pH (near neutral) conditions, highly active high-valence iron species Fe(VI) can also be generated. Fe(VI) has a high redox potential and stronger oxidizing capacity than most traditional water treatment oxidants. It can preferentially attack electron-rich components, thereby selectively removing organic pollutants containing electron-rich groups.

[0016] 3. The three-electrode treatment system selected a Fe / PbO2-DSA electrocatalytic oxidation dual-anode-cathode configuration. The DSA electrooxidation anode is a low-cost titanium-based PbO2 electrode, which, as a high oxygen evolution potential material, can both generate H2O• and catalyze the oxidation of Cl in the solution. - The generation of active chlorine and the theoretical potential for PbO2 to generate high-valence iron ions greatly reduce operating costs.

[0017] 4. The configuration design and process selection of this invention not only help reduce operating costs, but also provide a possible solution to the key problem of balancing the efficient degradation of pollutants and the inhibition of the generation of toxic chlorinated byproducts in chlorine-containing electro-oxidation systems by regulating the non-radical degradation pathway of high-valence iron generated in situ. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a three-electrode processing system.

[0019] Figure 2 The graph shows the effect of different operating parameters on the removal efficiency and energy consumption of sulfamethoxazole. (a)~(i) represent the effect of different operating parameters on the removal efficiency and energy consumption of sulfamethoxazole, respectively. Current density J: (a) removal rate, (b) reaction rate constant k, (c) power consumption; pH: (d) removal rate, (e) reaction rate constant k, energy consumption (f); Cl - Concentration: (g) removal rate, (h) reaction rate constant k, (i) energy consumption. Basic control conditions for each factor in the experiment: J = 30 mA / cm². 2 pH is 7, Cl - The concentration was 6000 mg / L, 0.1 M Na2SO4, and sulfamethoxazole concentration was 300 mg / L, with a degradation time of 3 h.

[0020] Figure 3 The diagram shows the removal effect of the three-electrode treatment system on COD, TOC and ammonia nitrogen.

[0021] Figure 4 The figures show a comparison of the removal efficiency of different background matrix ions and different pollutants. (a) to (c) show the effects of different background ions on the removal efficiency of (a) sulfamethoxazole and (b) the reaction rate constant, respectively; (c) shows a comparison of the removal efficiency of different pollutants in the study system.

[0022] Figure 5 The effects of SMX removal of reactive oxygen species and high-valent iron quenching on treatment efficiency and their respective contributions were quantified. (a)~(b) show the effects of different quenchers on the removal rate of sulfamethoxazole and the effects of various factors in the system, respectively. EC represents the effect of iron anode electrocoagulation, HO• represents the effect of TBA quenching, Fe(VI) represents the effect of DMSO, and ClO -This represents the effect of active chlorine, excluding the effects of electrocoagulation, HO• oxidation, and Fe(VI) oxidation.

[0023] Figure 6 EPR analysis of two-electrode and three-electrode treatment systems under different control conditions. (a)~(d) show the results of (a) two-electrode system (containing Cl) and (d) other conditions, respectively. - (b) Three-electrode system (containing Cl) - (c) A three-electrode system with added dimethyl sulfoxide (DMSO) (containing Cl) - (d) Three-electrode system without quencher (without Cl) - ).

[0024] Figure 7 The changes in iron ion and active chlorine content under different iron anode areas and current densities are shown. (a)~(d) represent the effects of different actual current densities on the degradation characteristics of the system: (a) degradation removal rate and (b) degradation rate constant; and the effects of different process current densities on the Fe content of the system. 2+ Effects of content (c) and active chlorine generation concentration (d).

[0025] Figure 8 The degradation characteristics of SMX in three-electrode and two-electrode systems were compared (SMX removal rate, energy consumption and degradation rate, comparison of different DSA anodes, and comparison of induced current). (a)~(c) respectively show the comparison of the degradation effect of (a) three-electrode configuration and induced current operation mode on SMX; (b) energy consumption and degradation rate of three-electrode and two-electrode systems; and (c) comparison of the degradation effect of different DSA anodes on SMX. Detailed Implementation

[0026] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples. The embodiments described below are exemplary and are intended to describe the present invention in more detail and specific ways, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] Organic compounds containing electron donors are those organic compounds that can donate electrons in redox reactions. These molecules contain numerous electron-donating groups (such as hydroxyl groups (-OH), amino groups (-NH2), and alkoxy groups (-OR). These groups donate electrons to the molecular skeleton through conjugation or inductive effects, resulting in a high overall electron cloud density. Such electron-rich organic pollutants can be selectively and rapidly removed by high-valence iron and singlet oxygen.

[0028] This invention is mainly aimed at this type of organic pollutant and is a wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode. It introduces an iron anode into a PbO2 electro-oxidation body to achieve efficient removal of organic matter containing electron donors. It mainly includes the configuration of a three-electrode treatment system and the design of optimized process control parameters.

[0029] refer to Figure 1 As shown, the three-electrode processing system configuration includes two anodes and one cathode. The cathode 4 is located at the center of the electrolytic cell, with the two anodes positioned on either side of it, and is expandable. The cathode 4 is made of stainless steel and serves as a shared cathode. The two anodes are an iron anode 3 and a titanium-based PbO2 functional anode 5, respectively. The two anodes are connected to the positive output of power supply 1, and the cathode 4 is connected to the negative output of power supply 1. The entire reactor 2 can be mounted on a magnetic stirrer 7, and a magnetic stir bar 6 is placed inside the reactor 2.

[0030] The cathode 4 can be made of 304 or 316 stainless steel, or replaced with nickel-plated carbon steel or graphite carbon, offering durability and good hydrogen evolution capability. The iron anode 3 can be made of pure iron plate or low-carbon steel. The titanium-based PbO2 functional anode 5 also exhibits good stability and service life, high catalytic oxidation and chlorine evolution activity, and the lead ion leaching during treatment must not exceed the lead ion discharge standard stipulated in the national water quality control standards.

[0031] Furthermore, the distance between the cathode and anode in the three-electrode treatment system is controlled to be 1.5-3 cm; the area of ​​the iron anode 3 should be controlled to be 1-1 / 6 of the total area of ​​the titanium-based PbO2 functional anode 5 and cathode 4 with the same size.

[0032] In practical applications, the iron anode 3 can be selected to be connected in parallel with the titanium-based PbO2 functional anode 5 as a second anode, or it can be selected to work as an induction electrode (not connected to the power supply and kept suspended).

[0033] The specific process of this invention involves feeding wastewater containing electron-donating organic matter into reactor 2, where it is removed and purified using a PbO2 electro-oxidation treatment system (i.e., a three-electrode treatment system) with an iron anode. The preferred process parameters are controlled as follows: current density on the titanium-based PbO2 functional anode 5 is 20-40 mA / cm². 2 The chloride ion content in the treated water is controlled at 4-8 g / L; the pH value of the treated water is controlled at 6-8. The power supply mode of power source 1 can be selected as DC or pulsed current without negative current.

[0034] In this invention, by using two anodes to share the same cathode, the highly efficient oxidative degradation capacity of electro-oxidation is utilized. Furthermore, the Fe(OH)3 flocs generated by the electrochemical dissolution of the iron anode impart adsorption / flocculation effects. The flotation effect triggered by the hydrogen evolution reaction at the shared cathode further enhances pollutant removal efficiency. Most importantly, under optimized pH (near-neutral) conditions, highly active high-valence iron species Fe(VI) can be generated. Fe(VI) possesses a high redox potential and stronger oxidizing capacity than most traditional water treatment oxidants, preferentially attacking electron-rich regions and selectively removing organic pollutants containing electron-rich groups. This invention provides a novel method for treating high-salt, recalcitrant organic industrial wastewater.

[0035] The following are some specific embodiments of the present invention.

[0036] Example 1: The wastewater to be treated was simulated wastewater prepared by adding electron-rich pollutants and 0.1 M sodium sulfate to deionized water. Different current densities (10-50 mA / cm²) were selected on an electrochemical water treatment device with a three-electrode configuration. 2 ), initial pH (3, 5, 7, 9, 11), Cl - The removal and energy consumption of SMX were investigated using three factors: concentration (2000-6000 mg / L), to determine the optimal operating parameters. Subsequently, the removal efficiency of the three-electrode treatment system for COD, TOC, and ammonia nitrogen was explored under the optimal operating parameters. Additionally, Cl was taken... - SO4² - HCO3 - and NH4 + Four typical ions were investigated to assess their effects on the degradation of SMX by the three-electrode treatment system. The degradation capacity of the three-electrode oxidation system for four electron-rich pollutants, namely NOR, CIP, IBU, and Phenol, was also explored.

[0037] In a three-electrode oxidation system, four different quenchers—tert-butanol (TBA), dimethyl sulfoxide (DMSO), benzoquinone (BQ), and furfuryl alcohol (FFA)—were added to determine their varying degrees of inhibition on SMX degradation, thus assessing the oxidative contribution of reactive species such as high-valent iron. In both two-electrode and three-electrode treatment systems, in addition to DMPO as a HO• scavenger, DMSO was introduced as a probe. Fe(IV) can oxidize DMSO to dimethyl sulfone (DMSO2), and free radicals react with it to generate products such as methanesulfonic acid and ethane, thereby identifying the Cl... - The necessity of generating Fe(VI) in a three-electrode treatment system.

[0038] To investigate the effects of changes in iron ion and active chlorine content on the formation of high-valence iron species such as Fe(VI), the area of ​​the iron electrode in the solution was adjusted from S (18 cm²) while keeping the current density through the anode constant. 2 Gradually decrease to 1 / 6S (3 cm) 2 The amount of iron ions deposited can be indirectly controlled by adjusting the anode area to regulate the intensity of the chlorine evolution reaction on the PbO2 anode surface, thereby determining the amount of Fe. 2+ The changes in the content of active chlorine to some extent controlled the formation of Fe(VI) and its intermediates, thereby affecting the changes in active species in the system.

[0039] Depend on Figure 1 As can be seen, the three-electrode processing system consists of two anodes and one cathode. The two anodes are a self-made Ti / PbO2 electrode and a DT-3 type Fe plate electrode, respectively, and the cathode is a stainless steel electrode. Each electrode has dimensions of 30 mm × 50 mm × 1 mm, with an effective area of ​​18 cm². The cathode 4 is located in the center of the electrolytic cell, with the two anodes positioned on either side of it.

[0040] Depend on Figure 2 It can be seen that at a current density of 30 mA / cm² 2 pH 7, Cl - At a concentration of 6000 mg / L, the iron ions dissolved at the iron anode react with active chlorine species (RCS, such as Cl•, ClO•, HOCl) generated in the solution to produce high-valence iron ions Fe(VI). This, along with HO• and active chlorine, enhances the oxidation process, achieving an optimal current efficiency (the ratio of the actual amount of electricity used to oxidize pollutants on the electrode to the total amount of electricity passing through the electrochemical reactor) of 89.28%, with an energy consumption of only 7.25 kWh / m³. 3 Here, the current efficiency refers to the ratio of the amount of electricity actually used on the electrodes to oxidize pollutants to the total amount of electricity passing through the electrochemical reactor, reflecting the effectiveness of electrical energy utilization.

[0041] Depend on Figure 3 It can be seen that due to the participation of iron anode 3, COD showed a significant removal effect, with a removal rate of 60.14%; the TOC removal trend was similar, with a removal rate of 55.70%; due to the attack of target pollutant molecules by strong oxidants such as HO•, active chlorine and Fe(VI), the amino groups were released and then rapidly hydrolyzed into free ammonia. After 3 h of treatment, the immediate ammonia nitrogen concentration in the water dropped to 1.12 mg / L (the initial ammonia nitrogen concentration was zero, and the concentration here is generated during the oxidation of pollutants).

[0042] Depend on Figure 4 It can be seen that SO4² - HCO3 - and NH4+ Both SO4²⁻ and SO4²⁻ showed inhibitory effects on the oxidative degradation and removal of SMX, with the order of inhibitory strength being: SO4²⁻ - >NH4 + >HCO3 - Cl - The presence of [a specific substance] promotes iron ion cycling, which is conducive to the formation of high-valence iron species, thereby enhancing the selective oxidation capacity for SMX. Furthermore, within the same degradation time, the system showed significant removal effects on all electron-rich pollutants, with degradation rates in the following order: NOR 95.97%, CIP 96.33%, IBU 89.63%, and Phenol 89.28%. This indicates that the system provides pollutant targeting for the widespread application of processes in practical wastewater treatment.

[0043] Depend on Figure 5 It was found that the addition of TBA, FFA, DMSO, and BQ reduced the degradation rate of SMX to varying degrees, decreasing by 65.09%, 73.79%, 43.51%, and 80.24%, respectively. Among these, DMSO quenching had the most significant inhibitory effect on the oxidative degradation of SMX, reducing the removal rate from 89.28% to 43.51%. This indicates that Fe(VI) is the dominant active species in the degradation process, followed by HO• and [other active species]. 1 O2 plays an important role.

[0044] Depend on Figure 6 It can be seen that in Cl - In the presence of Cl, both the two-electrode and three-electrode treatment systems exhibited a quadruple characteristic peak (peak intensity ratio 1:2:2:1) during SMX degradation, and the DMPO-OH adduct signal was strong, indicating that both systems could generate HO•, but it could also originate from Fe(IV). By introducing DMSO as a probe, the DMPO-OH signal was significantly suppressed in the three-electrode treatment system after the addition of DMSO, and a clear carbon-center radical signal appeared, but in the absence of Cl... - No characteristic signal peaks were observed in the three-electrode treatment system, indicating that when an iron anode was present in the system, an active species different from HO• was indeed generated, namely Fe(VI).

[0045] Depend on Figure 7 It can be seen that reducing the iron anode area from S to 1 / 6S, and increasing the actual current density, should significantly increase the Fe generated by anode dissolution. 2+ The ion concentration allows it to react with the PbO2 anode surface to catalyze the formation of Cl2 water-soluble HClO, generating Fe(VI) or Fe²⁺. + Fe is generated under the strong oxidizing action of active chlorine. 3+ This leads to the formation of Fe(VI). As the current density increases, active chlorine accumulates and readily reacts with Fe.2+ The reaction will promote Fe 2+ Oxidized to Fe 3+ The latter can be further converted into Fe(VI), thus enhancing the oxidation capacity of the system.

[0046] Depend on Figure 8 It was found that, using dual anodes (PbO2 anode and iron anode) and single anodes (PbO2 anode only), with stainless steel as the cathode, the degradation experiment of 300 mg / L SMX was carried out. After 3 h of degradation, the electro-oxidation degradation rate of PbO2 anode alone reached 78.39%, while the three-electrode treatment system with iron anode increased to 89.28%. This indicates that the introduction of iron anode in the dual anode system, on the one hand, the iron ions generated at the anode react with HClO produced by the catalytic oxidation of PbO2 anode to generate Fe(VI) (which is unstable and may also be converted to Fe(V) or Fe(IV)). These species, together with HO• and active chlorine, enhance the oxidation capacity. In addition, the formation of Fe(OH)3 flocs can enhance the adsorption and flocculation capacity of the system.

[0047] The energy consumption per unit area of ​​the dual-anode, three-electrode configuration system is 7.25 kWh / m³, while that of the PbO₂ anodic electro-oxidation system is 28.7 kWh / m³. 3 This indicates that the three-electrode configuration system incorporating an iron anode can significantly reduce the energy consumption cost of treatment. Furthermore, comparing the degradation and removal of SMX using three-electrode systems composed of titanium-based PbO2 anodes, noble metal RuO2 and IrO2 anodes, and iron anodes and stainless steel cathodes respectively, reveals that the degradation rate is 89.28% for the Ti / PbO2 electrode, 55.71% for the Ti / IrO2 electrode, and 83.79% for the Ti / RuO2 electrode. Therefore, selecting the Ti / PbO2 electrode as the DSA electro-oxidation functional anode in the three-electrode treatment system not only provides better degradation but also offers cost advantages, making it an effective and feasible choice. Simultaneously, disconnecting the power supply to the iron anode and generating iron ions through induced current to produce high-valence iron species for oxidative degradation of pollutants also yields good treatment results, with a degradation rate of 95.02%.

[0048] Through the above experiments and investigations of active species, it is evident that the three-electrode electrochemical treatment system constructed in this invention exhibits significant advantages in both treatment efficiency and energy consumption cost, especially in the treatment of high-salinity wastewater. This electrode configuration can fully utilize the Cl- in the wastewater. -Furthermore, the dissolution of the iron anode and its reaction with active chlorine can generate Fe(VI) in situ, enhancing the selective oxidation of pollutants and reducing the formation of highly toxic chlorination byproducts. In addition, the formation of Fe(OH)3 flocs helps the system achieve a synergistic effect of oxidation and flocculation. This not only provides a feasible process option for the treatment of recalcitrant organic wastewater in industry but also offers new insights into the selection of electrode materials for electrochemical water treatment.

[0049] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode, characterized in that, include: A three-electrode processing system is constructed, comprising two anodes and one cathode. The two anodes are distributed on both sides of the cathode, one anode being a titanium-based PbO2 functional anode and the other anode being an iron anode. The three-electrode treatment system was used to treat wastewater containing electron-donating organic matter, with the current density of the titanium-based PbO2 functional anode controlled at 20-40 mA / cm². 2 The chloride ion content in the wastewater is controlled at 4-8 g / L, and the pH value is controlled at 6-8; the treatment time is 2-5 h.

2. The wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode according to claim 1, characterized in that, The cathode is made of stainless steel, graphite carbon, or nickel-plated carbon steel; the iron anode is made of pure iron plate or low-carbon steel.

3. The wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode according to claim 1, characterized in that, In the three-electrode processing system, the distance between the cathode and anode is controlled to be 1.5-3 cm; the dimensions of the titanium-based PbO2 functional anode and cathode are kept the same, and the area of ​​the iron anode is 1 to 1 / 6 of the area of ​​the titanium-based PbO2 functional anode.

4. The wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode according to claim 1, characterized in that, The iron anode is connected in parallel with the titanium-based PbO2 functional anode, or it works as an induction electrode.

5. The wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode according to claim 1, characterized in that, The three-electrode processing system is powered by either direct current or pulsed current without negative current.

6. The wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode according to claim 1, characterized in that, The electron-rich organic compounds include one or more of sulfamethoxazole (SMX), norfloxacin (NOR), and ciprofloxacin (CIP), and the electronic groups include one or more of hydroxyl-OH, amino-NH2, and alkoxy-OR.

7. The wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode according to claim 1, characterized in that, The three-electrode processing system is configured in multiple groups, each group including two anodes and one cathode.

8. The wastewater treatment method for removing electron-rich organic pollutants by introducing an iron anode according to claim 1, characterized in that, The current density of the titanium-based PbO2 functional anode is 30 mA / cm². 2 When the chloride ion concentration in the wastewater was 6000 mg / L and the pH value was 7, the treatment efficiency for sulfamethoxazole (SMX) was 89.28%, and the energy consumption was 7.25 kWh / m³. 3 The COD removal rate was 60.14%, the TOC removal rate was 55.72%, the degradation rate of norfloxacin (NOR) was 95.97%, the degradation rate of ciprofloxacin (CIP) was 96.34%, the degradation rate of ibuprofen (IBU) was 89.62%, and the degradation rate of phenol (Phenol) was 90.39%.

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