A halogen by-product reduction system and reduction method

Abstract

The application discloses a halogenated by-product reduction and control system and method in the technical field of water treatment, which comprises an electrochemical reaction unit, a water inlet unit and a water outlet unit, the electrochemical reaction unit is used for generating a cathode electro-Fenton reaction and reducing halogenated by-products generated in an electron transfer process, the water inlet unit is used for continuously supplying liquid water to the electrochemical reaction unit, a water outlet of the water inlet unit is sealingly connected to a water inlet of the electrochemical reaction unit, and the water outlet unit is used for collecting water discharged from the electrochemical reaction unit. The application combines a through-flow type anode oxidation process with a through-flow type cathode electro-Fenton reaction process driven by endogenous molecular oxygen, constructs a continuous through-flow type coupled electrochemical water treatment system, realizes efficient removal of pollutants in water under a low potential condition, and improves the treatment efficiency of sewage.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of water treatment, and particularly relates to a halogenated by-product reduction and control system and a halogenated by-product reduction and control method. BACKGROUND

[0002] As a kind of advanced water treatment technology for removing organic pollutants in water, the anodic oxidation technology relies on the direct electron transfer process between pollutants and electrodes and the indirect oxidation process mediated by active species (such as hydroxyl radicals generated by electrolysis of water and active chlorine generated by electrolysis of chlorine) generated on the electrode surface to achieve effective degradation of pollutants. However, since the actual sewage is usually a complex system containing halogen ions, mainly chloride ions, the generation of toxic halogenated by-products often accompanies the reaction process. Although chloride ions can promote the removal of organic pollutants by being converted into active chlorine on the anode surface, this process may also generate chlorinated organic pollutants that are more toxic than the parent compounds. Moreover, active chlorine can be further oxidized into toxic inorganic chlorinated by-products (mainly chlorate and perchlorate) on the anode surface. In theory, reducing the operating potential of the flow-through anode can effectively reduce the generation of chlorinated by-products. Even when the operating potential of the flow-through anode is controlled below the chlorine evolution potential, the participation of chloride ions in the anodic oxidation reaction can be shielded, thereby completely avoiding the generation of chlorinated by-products (such as the patent document with the application number CN202410682951.5 discloses an electrochemical sewage treatment device and method).

[0003] However, reducing the operating potential of the flow-through anode will inevitably reduce the amount of hydroxyl radicals generated by the flow-through anode, greatly reducing the treatment efficiency of the flow-through anode oxidation system for sewage, especially for some high ionization potential pollutants (such as atrazine, phenylacetic acid and nitrobenzene), which also makes it difficult to effectively improve the treatment effect of such polluted water bodies. SUMMARY

[0004] The application aims to provide a halogenated by-product reduction and control system and method, which can effectively remove pollutants in water under low potential conditions and reduce the generation of halogenated by-products. By combining the flow-through anode oxidation process with the flow-through cathode electro-Fenton reaction process driven by endogenous molecular oxygen, a continuous flow-through mode coupled electrochemical water treatment system is constructed, which realizes efficient removal of pollutants in water under low potential conditions and improves the treatment efficiency of sewage, especially for high ionization potential pollutants.

[0005] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0006] In a first aspect, a system for reducing and controlling halogenated byproducts is provided, comprising an electrochemical reaction unit, a water inlet unit, a water outlet unit, and a molecular oxygen compensation unit. The electrochemical reaction unit is used to perform a cathodic electro-Fenton reaction and reduce the halogenated byproducts generated during electron transfer. The water inlet unit is used to continuously supply liquid water to the electrochemical reaction unit, and the outlet of the water inlet unit is sealed to the inlet of the electrochemical reaction unit. The water outlet unit is used to collect the water discharged from the electrochemical reaction unit, and the inlet of the water outlet unit is sealed to the outlet of the electrochemical reaction unit. The molecular oxygen compensation unit is used to compensate for oxygen molecules escaping from the electrochemical reaction unit.

[0007] As a further aspect of the present invention: the electrochemical reaction unit includes a closed electrochemical reaction cell and a DC regulated power supply, and a penetrating cathode plate and a penetrating anode plate are installed inside the closed electrochemical reaction cell;

[0008] The two opposite sides of the closed electrochemical reaction cell are respectively connected to the first guide pipe and the second guide pipe;

[0009] A second terminal is fixed to the side of the cathode plate, and the second terminal is connected to the negative terminal of the DC regulated power supply. A first terminal is fixed to the side of the anode plate, and the first terminal is connected to the positive terminal of the DC regulated power supply.

[0010] The current density of the DC regulated power supply is 5 mA / cm². 2 ~20 mA / cm 2 The water flow rate in the closed electrochemical reactor is 50 L / m. 2 / min~500 L / m 2 / min.

[0011] As a further embodiment of the present invention: the penetrating cathode plate and the penetrating anode plate are arranged in parallel relative to each other, the distance between the penetrating cathode plate and the penetrating anode plate is 0.2 cm to 5 cm, the penetrating cathode plate is perpendicular to the water flow direction of the first guide pipe, and both the penetrating cathode plate and the penetrating anode plate include an electrode plate and an insulating frame fixed on the side of the electrode plate. The penetrating cathode plate and the penetrating anode plate are respectively fixed to the inner wall of the closed electrochemical reaction cell through the insulating frame.

[0012] As a further aspect of the present invention: the two penetrating cathode plates have multiple first perforations through their sides, and the penetrating anode plate has multiple second perforations through its side. The diameter of the first perforations is larger than the diameter of the second perforations. Both the first and second perforations are used to guide water flow through the penetrating cathode plate and the penetrating anode plate.

[0013] The material penetrating the anode plate is one of SnO2-Sb-Ti, RuO2-Ti, β-PbO2-Ti, Ti4O7, RuO2-IrO2-Ti, SnO2-Bi-Ti, or BDD;

[0014] The material of the cathode plate 1 is one of the following: B / N (boron / nitrogen) co-doped high-purity carbon felt, B / N (boron / nitrogen) co-doped carbon nanotubes, a filter membrane made of graphene material, or sulfur-doped Fe2O3, Co3O4, or Cu2O.

[0015] As a further aspect of the present invention: sealing flanges are installed at the connection points of the second terminal and the first terminal with the closed electrochemical reaction cell, and the sealing flanges are made of insulating material;

[0016] A connection switch is installed on the second terminal and the first terminal respectively. The two connection switches are used to control the opening and closing of the electrical connection path between the second terminal and the first terminal and the DC regulated power supply, which facilitates the improvement of the start-up efficiency of the electrochemical reaction in the closed electrochemical reaction cell.

[0017] As a further aspect of the present invention: the water inlet unit includes a first pipe and a water inlet pool, with the two ends of the first pipe connected to the water inlet pool and a second guide pipe, respectively.

[0018] As a further aspect of the present invention: the water outlet unit includes a second pipe, a measuring structure and an outlet pool. The measuring structure is used to measure the pressure and flow rate of the water in the second pipe. The two ends of the second pipe are respectively connected to the outlet pool and the first guide pipe. The booster pump is installed in the middle of the first pipe and / or the second pipe. The water flow direction is from the penetrating anode plate to the penetrating cathode plate.

[0019] As a further aspect of the present invention: the measuring structure includes a water pressure gauge and a flow meter, which are respectively installed through the surface of the second pipe.

[0020] As a further aspect of the present invention: the system further includes a molecular oxygen compensation unit, which is used to compensate for oxygen molecules escaping in the electrochemical reaction unit. The molecular oxygen compensation unit includes a compensation pipe, one end of which penetrates the interior of the closed electrochemical reaction cell and is located between the penetrating cathode plate and the penetrating anode plate.

[0021] One end of the compensation pipeline is connected to the transfer bottle, and the top of the transfer bottle is connected to the gas tube. A first one-way valve is installed on the surface of the gas tube, and a second one-way valve is installed at the connection between the compensation pipeline and the transfer bottle. A pressure gauge is installed on the top of the oxygen supply cylinder.

[0022] Secondly, a method for reducing and controlling halogenated byproducts is also provided, applied to the halogenation byproduct reduction and control system described in the above scheme, the method comprising:

[0023] The wastewater to be treated is introduced into the interior of a closed electrochemical reactor;

[0024] Close the connection switch located on the first and second terminals to connect the through cathode plate and through anode plate to the negative and positive terminals of the DC regulated power supply, respectively.

[0025] Connect the power supply to the booster pump to introduce water from the inlet tank into the closed electrochemical reaction tank, while the second pipeline introduces the treated water into the outlet tank.

[0026] After a certain reaction time, the power is cut off to the penetrating cathode plate and the penetrating anode plate.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. This invention, through the coupling of a through-flow anodic oxidation process and the reliance on endogenous molecular oxygen to drive the through-flow cathode electro-Fenton reaction, enables the endogenous oxygen generated by water electrolysis through the anode during the operation of the treatment system. This endogenous oxygen is then transported with the water flow to the through cathode and converted into hydroxyl radicals through the electro-Fenton reaction process. This compensates for the deficiency of free radical generation caused by the reduced potential of the through anode, enabling the entire system to achieve high free radical production at low potential.

[0029] 2. By employing low potential conditions, this invention can significantly reduce the reaction process between halide ions in wastewater and the electrode, effectively inhibiting the formation and further transformation of active halogens, thereby significantly reducing the formation of inorganic and organic halogenated byproducts.

[0030] 3. The through-flow cathode of the present invention can not only generate an electro-Fenton process, but also electro-reduce halogenated byproducts. By reducing the halogenated byproducts generated by penetrating the anode at the through-cathode, the generation of halogenated byproducts in the reaction system is further reduced, thereby achieving efficient removal of pollutants in water and reduction control of halogenated byproducts under low potential conditions.

[0031] 4. This invention can effectively remove pollutants from water under low potential conditions, consume less electrical energy, and reduce the generation of halogenated byproducts. By combining the through-flow anodic oxidation process with the through-flow cathode electro-Fenton reaction process driven by endogenous molecular oxygen, a continuous through-flow coupled electrochemical water treatment system is constructed, which realizes the efficient removal of pollutants from water under low potential conditions and improves the wastewater treatment efficiency, especially for pollutants with high ionization potential. The through-flow cathode reaction process of this invention also has the function of electroreducing halogenated byproducts, effectively realizing the reduction and control of halogenated byproduct generation during water treatment. Attached Figure Description

[0032] Figure 1 This is a structural diagram of the electrochemical system for controlling the generation of halogenated byproducts according to the present invention;

[0033] Figure 2 For the present invention Figure 1 Enlarged view of A in the middle;

[0034] Figure 3 This is a front view of the through-hole cathode plate of the present invention;

[0035] Figure 4 These are graphs showing the pollutant removal rate results in the first, second, and third embodiments of the present invention.

[0036] Figure 5 Different Cl in the first, second, and third embodiments of the present invention - Graph showing the formation of various halogenated disinfection byproducts at different concentrations;

[0037] Figure 6 The graphs show the pollutant removal rates of different electrochemical systems in the fifth and second embodiments of the present invention.

[0038] Figure 7 The graph shows the hydroxyl radical generation results of different electrochemical systems in the sixth, seventh, and fourth embodiments of the present invention.

[0039] Figure 8 The graph shows the generation results of various halogenated disinfection byproducts in different electrochemical systems in the eighth and second embodiments of the present invention.

[0040] Figure 9 This is a flowchart illustrating the method steps of the present invention.

[0041] In the diagram: 1. Penetrating cathode plate; 2. Penetrating anode plate; 3. DC regulated power supply; 4. Booster pump; 5. Inlet tank; 6. Outlet tank; 7. Sealing flange; 8. Second terminal; 9. First terminal; 10. First guide pipe; 11. Second guide pipe; 12. Second pipeline; 13. Closed electrochemical reaction cell; 14. First pipeline; 15. Water pressure gauge; 16. Flow meter; 17. Insulating frame; 18. Connecting switch; 19. Compensation pipeline; 191. Second check valve; 20. Transfer bottle; 21. Gas pipe; 22. First check valve; 23. Oxygen supply cylinder. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Please seeFigure 1 - Figure 3 The present invention discloses a system for reducing and controlling halogenated byproducts, comprising an electrochemical reaction unit, a water inlet unit, and a water outlet unit. The electrochemical reaction unit is used to perform a cathodic electro-Fenton reaction and reduce the halogenated byproducts generated during electron transfer. The water inlet unit is used to continuously supply liquid water to the electrochemical reaction unit, and the outlet of the water inlet unit is sealed and connected to the inlet of the electrochemical reaction unit. The water outlet unit is used to collect the water discharged from the electrochemical reaction unit, and the inlet of the water outlet unit is sealed and connected to the outlet of the electrochemical reaction unit.

[0044] Preferably, the electrochemical reaction unit includes a closed electrochemical reaction cell 13 and a DC regulated power supply 3, and a penetrating cathode plate 1 and a penetrating anode plate 2 are installed inside the closed electrochemical reaction cell 13.

[0045] The two opposite sides of the closed electrochemical reaction cell 13 are respectively connected to the first guide pipe 10 and the second guide pipe 11;

[0046] A second terminal 8 is fixed to the side of the cathode plate 1, and the second terminal 8 is connected to the negative terminal of the DC regulated power supply 3. A first terminal 9 is fixed to the side of the anode plate 2, and the first terminal 9 is connected to the positive terminal of the DC regulated power supply 3. By applying a low potential to drive the system operation, the reaction process between halide ions in wastewater and the electrodes is significantly reduced, effectively inhibiting the conversion of halide ions to active halide at the anode and the further conversion of active halide, thereby significantly reducing the formation of inorganic and organic halogenated byproducts. This can effectively prevent the formation of Cl in the water matrix. - ClO3 is generated by the reaction with the electrode at a high potential. - and ClO4 - ;

[0047] The current density of DC regulated power supply 3 is 5 mA / cm². 2 ~20 mA / cm 2 The water flow rate in the closed electrochemical reactor 13 is 50 L / m 2 / min~500 L / m 2 / min.

[0048] Preferably, the penetrating cathode plate 1 and the penetrating anode plate 2 are arranged in parallel relative to each other, with a distance of 0.2 cm to 5 cm between them. The penetrating cathode plate 1 is perpendicular to the water flow direction of the first guide pipe 10. Both the penetrating cathode plate 1 and the penetrating anode plate 2 include an electrode plate and an insulating frame 17 fixed to the side of the electrode plate. The penetrating cathode plate 1 and the penetrating anode plate 2 are respectively fixed to the inner wall of the closed electrochemical reaction cell 13 through the insulating frame 17.

[0049] Preferably, the sides of the two penetrating cathode plates 1 are perforated with multiple first perforations, and the sides of the penetrating anode plate 2 are perforated with multiple second perforations. The diameter of the first perforations is larger than that of the second perforations. The diameter of the first perforations is 30 μm to 50 μm, and the diameter of the second perforations is 5 μm to 10 μm. This allows excess molecular oxygen (O2) generated by the penetrating anode plate 2 to pass smoothly through the penetrating cathode plate 1, avoiding the retention and aggregation of excess molecular oxygen (O2) by the penetrating cathode plate 1, which would affect the stable operation of the reaction system. Both the first and second perforations are used to guide the water flow through the penetrating cathode plate 1 and the penetrating anode plate 2. The first and second perforations are arranged alternately in the direction from the penetrating anode plate 2 to the penetrating cathode plate 1, thus constructing a continuous flow-coupled electrochemical water treatment system. The water flow direction is from the penetrating anode plate 2 to the penetrating cathode plate 1. This is because the water flow direction is conducive to the transport of the endogenous oxygen generated by the electrolysis of water by the penetrating anode plate 2 to the penetrating cathode plate 1 to undergo the two-electron reduction reaction of O2 to generate hydrogen peroxide (H2O2).

[0050] The material of the penetrating anode plate 2 is one of SnO2-Sb-Ti, RuO2-Ti, β-PbO2-Ti, Ti4O7, RuO2-IrO2-Ti, SnO2-Bi-Ti, and BDD. The penetrating anode plate 2 made of the above materials has good direct electron transfer (DET) efficiency and oxygen evolution performance, but poor chlorine evolution performance. The penetrating anode plate 2 adopts a porous electrode material with molecular oxygen O2 as the main product. After applying current, the porous penetrating anode plate 2 generates molecular oxygen O2 through the four-electron oxidation reaction of H2O. At the same time, the penetrating anode plate 2 made of the above materials degrades pollutants through the direct electron transfer (DET) process during the anodizing process.

[0051] The material penetrating cathode plate 1 is selected from one of the following: B / N (boron / nitrogen) co-doped high-purity carbon felt, B / N (boron / nitrogen) co-doped carbon nanotubes, a filter membrane constructed from graphene materials, or sulfur-doped Fe2O3, Co3O4, and Cu2O. Considering that the above materials exhibit high selectivity and reaction efficiency for the two-electron reduction reaction of O2 to generate hydrogen peroxide (H2O2) during the cathode electro-Fenton reaction, the penetrating cathode plate 1 is designed to facilitate this process. Furthermore, the B / N (boron / nitrogen) co-doped porous material not only provides abundant active sites but also effectively increases the specific surface area and porous structure, resulting in high efficiency in activating hydrogen peroxide (H2O2) to generate hydroxyl radicals (•OH). During the cathode electro-reduction dehalogenation process, the large specific surface area and abundant pore structure of the above materials in the penetrating cathode plate 1, along with their high electron conductivity, can serve as electron transport channels to promote the reduction reaction of halogenated byproducts on the cathode surface.

[0052] Preferably, sealing flanges 7 are installed at the connection points of the second terminal 8 and the first terminal 9 with the closed electrochemical reaction cell 13. The sealing flanges 7 are made of insulating material.

[0053] A connection switch 18 is installed on the second terminal 8 and the first terminal 9 respectively. The two connection switches 18 are used to control the opening and closing of the electrical connection between the second terminal 8 and the first terminal 9 and the DC regulated power supply 3, so as to improve the start-up efficiency of the electrochemical reaction in the closed electrochemical reaction cell 13.

[0054] Preferably, the water inlet unit includes a first pipe 14 and a water inlet pool 5, with the two ends of the first pipe 14 connected to the water inlet pool 5 and the second guide pipe 11, respectively.

[0055] Preferably, the water outlet unit includes a second pipe 12, a measuring structure, and an outlet pool 6. The measuring structure is used to measure the pressure and flow rate of the water in the second pipe 12. The two ends of the second pipe 12 are respectively connected to the outlet pool 6 and the first guide pipe 10. The lift pump 4 is installed in the middle of the first pipe 14 and / or the second pipe 12. The water flow direction is from the penetrating anode plate 2 to the penetrating cathode plate 1. The lift pump 4 provides driving force for the continuous flow of water in the system.

[0056] Preferably, the measuring structure includes a pressure gauge 15 and a flow meter 16, which are respectively installed through the surface of the second pipe 12.

[0057] Preferably, the system further includes a molecular oxygen compensation unit, which is used to compensate for oxygen molecules escaping in the electrochemical reaction unit. The molecular oxygen compensation unit includes a compensation pipe 19, one end of which penetrates the interior of the closed electrochemical reaction cell and is located between the penetrating cathode plate and the penetrating anode plate. The molecular oxygen compensation unit includes a compensation pipe 19, one end of which penetrates the interior of the closed electrochemical reaction cell 13 and is located between the penetrating cathode plate 1 and the penetrating anode plate 2.

[0058] One end of the compensation pipe 19 is connected to the transfer bottle 20, and the top of the transfer bottle 20 is connected to the air pipe 21. A first one-way valve 22 is installed on the surface of the air pipe 21. A second one-way valve 191 is installed at the connection between the compensation pipe 19 and the transfer bottle 20. A pressure gauge is installed on the top of the oxygen supply bottle 23.

[0059] The electrolysis system of this invention operates as follows: Wastewater to be treated is powered by a booster pump 4 and flows from the inlet tank 5 through a first pipe 14 and a second guide pipe 11 on one side of the penetrating anode plate 2 into a closed electrochemical reaction tank 13. After the closed electrochemical reaction tank 13 is filled with wastewater, it flows out from the outlet on one side of the penetrating cathode plate 1 and enters the outlet tank 6 through a second pipe 12, forming a closed loop. A DC regulated power supply 3 is then connected, and electrochemical treatment of the wastewater begins. H2O adsorbed on the surface of the penetrating anode plate 2 undergoes a four-electron oxidation reaction to generate molecular oxygen O2. Simultaneously, a direct electron transfer (DET) process occurs on the penetrating anode plate 2, degrading pollutants. Molecular oxygen O2 is transported to the penetrating cathode plate 1 via convection, where it undergoes a two-electron reduction reaction to generate hydrogen peroxide (H2O2). The hydrogen peroxide H2O2 is then activated by a B / N (boron / nitrogen) co-doped catalyst loaded on the penetrating cathode plate 1 to generate hydroxyl radicals •OH. These hydroxyl radicals •OH participate in a free radical oxidation reaction to degrade pollutants. At the same time, halogenated byproducts generated at the penetrating anode can be reduced at the penetrating cathode. It achieves comprehensive enhancement of pollutant removal while reducing and controlling the generation of halogenated disinfection byproducts.

[0060] During the process, the wastewater to be treated continuously enters the closed electrochemical reaction tank 13 from the inlet tank 5 and reacts continuously in the closed electrochemical reaction tank 13 in the form of continuous flow before being discharged to the outlet tank 6. The pollutants are eventually degraded from the wastewater to be treated.

[0061] During system operation, polluted wastewater in inlet tank 5, driven by booster pump 4, enters closed electrochemical reaction tank 13 through its inlet. The polluted wastewater first passes through penetrating anode plate 2. Once the closed electrochemical reaction tank 13 is full of polluted wastewater, the system forms a closed loop and is connected to DC regulated power supply 3. Direct electron transfer (DET) occurs at penetrating anode plate 2, generating molecular oxygen (O2). This O2 is transported to penetrating cathode plate 1, where a two-electron reduction reaction occurs, generating hydrogen peroxide (H2O2). The B / N co-doped catalyst loaded on the penetrating cathode plate 1 activates the H2O2, generating hydroxyl radicals (•OH). These hydroxyl radicals participate in free radical oxidation reactions, degrading pollutants. Simultaneously, halogenated byproducts generated at the penetrating anode can be reduced at the penetrating cathode, achieving comprehensive enhancement of pollutant removal while reducing the generation of halogenated disinfection byproducts. The purified wastewater flows out through the outlet into effluent tank 6 after passing through the penetrating cathode plate 1.

[0062] The working principle of the halogenated by-product reduction and control system of the present invention is as follows:

[0063] Reaction 1: Water molecules H2O adsorbed on the surface of the penetrating anode plate 2 undergo a four-electron oxidation reaction to generate molecular oxygen O2;

[0064] Simultaneously, the direct electron transfer process (DET) occurs through the surface of anode plate 2, degrading pollutants.

[0065] Reaction 2: Molecular oxygen O2 generated at the anode is transported to the penetrating cathode plate 1 by the convection transport of the treated water sample, and undergoes a two-electron reduction reaction of O2 to generate hydrogen peroxide H2O2.

[0066] Reaction 3: The B / N (boron / nitrogen) co-doped catalyst on the penetrating cathode plate 1 further activates hydrogen peroxide (H2O2) into hydroxyl radicals (•OH). The hydroxyl radicals (•OH) participate in the radical oxidation reaction to degrade pollutants. At the same time, the halogenated byproducts generated at the penetrating anode can be reduced at the penetrating cathode. The three-stage reaction process is as follows:

[0067] 2H₂O → O₂ + 4H + + 4e - Reaction 1;

[0068] O2 + 2H2O + 2e - → H2O2 + 2OH - Reaction 2;

[0069] H2O2 + 2e - → •OH + OH - Reaction 3.

[0070] First embodiment:

[0071] This embodiment focuses on testing at higher Cl levels. - At certain concentrations, the pollutant removal efficiency and the reduction efficiency of halogenated disinfection byproducts of an electrochemical system for reducing and controlling the generation of halogenated byproducts were verified.

[0072] Specifically, simulated wastewater was used as the treatment target, atrazine was added at a dosage of 10 μmol / L, the electrolyte was a 15 mM NaCl solution, the cathode plate 1 was a filter membrane made of B / N (boron / nitrogen) co-doped carbon nanotubes with a pore size of 30 μm, and the anode plate 2 was a RuO2-Ti porous electrode with a pore size of 5 μm.

[0073] Specifically, the distance between the penetrating anode plate 2 and the penetrating cathode plate 1 is 2 cm, and the water flow velocity is set to 240 L / m. 2 / min, current density set to 15 mA / cm 2 The concentration of atrazine in the samples was measured and analyzed at 0, 5, 10, 20, 30, 45 and 60 min of electrolysis. The concentration of various halogenated disinfection byproducts in the samples was measured and analyzed at 60 min of electrolysis. The experiment was repeated multiple times to reduce the influence of error.

[0074] Specifically, after the electrolysis system ran for 60 minutes, the final removal rate of atrazine stabilized at over 90%, and the concentrations of both inorganic and organic halogenated disinfection byproducts were low.

[0075] Second embodiment:

[0076] This embodiment focuses on testing at lower Cl levels. - At certain concentrations, the pollutant removal efficiency and the reduction efficiency of halogenated disinfection byproducts of an electrochemical system for reducing and controlling the generation of halogenated byproducts were verified.

[0077] Specifically, simulated wastewater was used as the treatment target, atrazine was added at a dosage of 10 μmol / L, the electrolyte was a 5 mM NaCl solution, the cathode plate 1 was a B / N co-doped high-purity carbon felt with a pore size of 50 μm, and the anode plate 2 was a SnO2-Sb-Ti porous electrode with a pore size of 10 μm.

[0078] Specifically, the distance between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow velocity is set to 320 L / m. 2 / min, current density set to 10 mA / cm 2 The concentration of atrazine in the samples was measured and analyzed at 0, 5, 10, 20, 30, 45 and 60 min of electrolysis. The concentration of various halogenated disinfection byproducts in the samples was measured and analyzed at 60 min of electrolysis. The experiment was repeated multiple times to reduce the influence of error.

[0079] Specifically, after running for 60 minutes, the electrolysis system achieved a final removal rate of atrazine of over 95%, with the lowest concentrations of inorganic and organic halogenated disinfection byproducts.

[0080] Third embodiment:

[0081] This embodiment is for testing the concentration of Cl in a relatively small amount of Cl. - At certain concentrations, the pollutant removal efficiency and the reduction efficiency of halogenated disinfection byproducts of an electrochemical system for reducing and controlling the generation of halogenated byproducts were verified.

[0082] Specifically, simulated wastewater was used as the treatment target, atrazine was added at a dosage of 10 μmol / L, the electrolyte was a 10 mM NaCl solution, the cathode plate 1 used sulfur-doped Fe2O3 with a pore size of 40 μm, and the anode plate 2 used a β-PbO2-Ti porous electrode with a pore size of 5 μm.

[0083] Specifically, the distance between the penetrating anode plate 2 and the penetrating cathode plate 1 is 3 cm, and the water flow velocity is set to 160 L / m. 2 / min, current density set to 10 mA / cm 2 The concentration of atrazine in the samples was measured and analyzed at 0, 5, 10, 20, 30, 45 and 60 min of electrolysis. The concentration of various halogenated disinfection byproducts in the samples was measured and analyzed at 60 min of electrolysis. The experiment was repeated multiple times to reduce the influence of error.

[0084] Specifically, after the system ran for 60 minutes, the final removal rate of atrazine stabilized at over 85%, and the concentrations of both inorganic and organic halogenated disinfection byproducts were low.

[0085] Fourth embodiment:

[0086] This embodiment aims to test and verify the hydroxyl radical generation effect of an electrochemical system for reducing and controlling the generation of halogenated byproducts under low potential conditions.

[0087] Specifically, the electrolyte solution used is a 100 mM potassium dihydrogen phosphate solution + a 20 μM benzoic acid solution.

[0088] Specifically, the through-cathode plate 1 uses a B / N co-doped high-purity carbon felt with a pore size of 50 μm, and the through-anode plate 2 uses a SnO2-Sb-Ti porous electrode with a pore size of 10 μm.

[0089] Specifically, the distance between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow velocity is set to 320 L / m. 2 / min, current density set to 10 mA / cm 2 The concentration of hydroxyl radicals in the samples was measured and analyzed at 0, 5, 10, 20, 30, 45 and 60 min of electrolysis, and the experiment was repeated multiple times to reduce the influence of error.

[0090] Specifically, after the system ran for 60 minutes, the concentration of hydroxyl radicals stabilized at around 250 μM.

[0091] Fifth embodiment:

[0092] This embodiment uses an electrochemical device employing a single through-flow anodic oxidation technology, which is compared with the second embodiment.

[0093] Specifically, simulated wastewater was used as the treatment target, the dosage of atrazine was set to 10 μmol / L, the electrolyte solution was a 5 mM NaCl solution, a porous cathode plate 1 made of stainless steel with a pore size of 50 μm was used, and the anode plate 2 was a SnO2-Sb-Ti porous electrode with a pore size of 10 μm, the same as in the second embodiment.

[0094] Specifically, the distance between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow velocity is set to 320 L / m. 2 / min, current density set to 10 mA / cm 2 The atrazine concentration of the samples was measured and analyzed at 0, 5, 10, 20, 30, 45 and 60 mins after electrolysis, and the experiment was repeated multiple times to reduce the influence of error.

[0095] Specifically, after the system ran for 60 minutes, the final removal rate of atrazine stabilized at around 15%.

[0096] As can be seen from the above, the pollutant removal rate of the fifth embodiment is much lower than that of the second embodiment. This is because, driven by low potential conditions, the production of hydroxyl radicals in the fifth embodiment is insufficient, and it can only rely on the direct electron transfer process (DET) at the anode to react with the pollutants. This not only results in low degradation efficiency but also fails to completely oxidize pollutants with high ionization potential (IP). In contrast, the second embodiment not only utilizes the direct electron transfer process (DET) at the anode but also utilizes a through-flow cathode electro-Fenton reaction process driven by endogenous molecular oxygen. This successfully compensates for the shortcomings of insufficient free radical generation caused by the reduced potential at the through-anode in Comparative Example 1. The second embodiment enables the entire system to achieve a high free radical production while operating at low potential, thereby improving the pollutant degradation efficiency and effectively removing pollutants with high ionization potential (IP).

[0097] Sixth embodiment:

[0098] This embodiment uses an electrochemical device employing a single through-flow anodic oxidation technology, which is compared with the fourth embodiment.

[0099] Specifically, the electrolyte solution used is a 100 mM potassium dihydrogen phosphate solution + a 20 μM benzoic acid solution.

[0100] Specifically, in the sixth embodiment, a porous cathode plate 1 with a pore size of 50 μm is used, which is made of stainless steel. The porous anode plate 2 uses a SnO2-Sb-Ti porous electrode with a pore size of 10 μm, which is the same as in the fourth embodiment.

[0101] Specifically, the distance between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow velocity is set to 320 L / m. 2 / min, current density set to 10 mA / cm 2 The concentration of hydroxyl radicals in the samples was measured and analyzed at 0, 5, 10, 20, 30, 45 and 60 min of electrolysis, and the experiment was repeated multiple times to reduce the influence of error.

[0102] Specifically, after the system ran for 60 minutes, the concentration of hydroxyl radicals stabilized at around 25 μM.

[0103] Seventh embodiment:

[0104] This embodiment uses an electrochemical device employing a single through-flow anodic oxidation technology, which is compared with the fourth embodiment.

[0105] Specifically, the electrolyte solution used is a 100 mM potassium dihydrogen phosphate solution + a 20 μM benzoic acid solution.

[0106] Specifically, a porous cathode plate 1 with a pore size of 50 μm is used, made of stainless steel, and a porous anode plate 2 with a pore size of 10 μm is used, which is the same as in the fourth embodiment.

[0107] Specifically, the distance between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow velocity is set to 320 L / m. 2 / min, current density set to 30 mA / cm 2 The concentration of hydroxyl radicals in the samples was measured and analyzed at 0, 5, 10, 20, 30, 45 and 60 min of electrolysis, and the experiment was repeated multiple times to reduce the influence of error.

[0108] Specifically, after the system ran for 60 minutes, the concentration of hydroxyl radicals stabilized at around 250 μM.

[0109] It can be seen that the hydroxyl radical production in the sixth embodiment is much lower than that in the fourth embodiment. This is because, under low-potential driving, the sixth embodiment relies solely on the penetration anode for water electrolysis, resulting in insufficient hydroxyl radical production. In contrast, the fourth embodiment utilizes the endogenous oxygen generated by the penetration anode electrolysis, which is transported with the water flow to the penetration cathode and converted into hydroxyl radicals through an electro-Fenton reaction process. This allows the entire system to achieve a higher radical production even at a low potential. It is worth noting that in this embodiment, to achieve the same amount of hydroxyl radical production as the fourth embodiment, the potential needs to be increased by at least three times. In other words, the fourth embodiment can achieve a certain amount of hydroxyl radical production at a low potential, thereby ensuring pollutant removal and reducing energy consumption.

[0110] Eighth embodiment:

[0111] This embodiment uses an electrochemical device employing a single through-flow anodic oxidation technology, which is compared with the second embodiment.

[0112] Specifically, simulated wastewater was used as the treatment target, the dosage of atrazine was set to 10 μmol / L, and the electrolyte solution was a 5 mM NaCl solution.

[0113] Specifically, a porous cathode plate 1 with a pore size of 50 μm is used, made of stainless steel, and a porous anode plate 2 with a pore size of 10 μm is used, which is the same as the pore size in the second embodiment.

[0114] Specifically, the distance between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow velocity is set to 320 L / m. 2 / min, current density set to 10 mA / cm 2 The concentrations of various halogenated disinfection byproducts in the samples were measured and analyzed after 60 minutes of electrolysis, and the experiment was repeated multiple times to reduce the influence of errors.

[0115] Specifically, after the system ran for 60 minutes, the concentration of various halogenated disinfection byproducts was relatively high.

[0116] It can be seen that the concentrations of various halogenated disinfection byproducts in this embodiment are significantly higher than those in the second embodiment. This is because although the low potential applied in this embodiment inhibits the process of halide ions converting to active halogen and further conversion of active halogen at the anode, effectively reducing the generation of halogenated byproducts, the second embodiment, compared to this embodiment, also makes additional effective use of the electrochemical cathode reduction dehalogenation reaction, reducing the halogenated byproducts generated through the anode at the cathode, thus strengthening the control of the reduction of halogenated disinfection byproduct generation.

[0117] like Figure 9 As shown, a method for reducing and controlling halogenated byproducts is also provided, applicable to a system for reducing and controlling halogenated byproducts as described above. The method includes the following steps:

[0118] S1: The wastewater to be treated is introduced into the interior of the closed electrochemical reactor 13;

[0119] S2: Close the connection switch 18 located on the first terminal 9 and the second terminal 8 to connect the through cathode plate 1 and through anode plate 2 to the negative and positive terminals of the DC regulated power supply 3, respectively.

[0120] S3: Connect the power supply to the booster pump 4 to introduce the water in the inlet pool 5 into the closed electrochemical reaction tank 13, while the second pipe 12 introduces the treated water into the outlet pool 6.

[0121] S4: After a certain reaction time, the power is cut off to the penetrating cathode plate 1 and the penetrating anode plate 2.

[0122] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A halogen by-product abatement system characterized by, The system comprises: an electrochemical reaction unit for generating a cathode electro-Fenton reaction and reducing halogenated by-products generated in an electron transfer process; the electrochemical reaction unit comprises a closed electrochemical reaction cell and a direct current stabilized power supply, and a penetrating cathode plate and a penetrating anode plate are installed inside the closed electrochemical reaction cell; two opposite sides of the closed electrochemical reaction cell are respectively connected with a first flow guide pipe and a second flow guide pipe; a second terminal post is fixed to the side of the penetrating cathode plate, and the second terminal post is connected with a negative electrode of the direct current stabilized power supply; a first terminal post is fixed to the side of the penetrating anode plate, and the first terminal post is connected with a positive electrode of the direct current stabilized power supply; The current density of the direct current stabilized power supply is 5 mA / cm 2 ~20 mA / cm 2 The water flow flux in the closed electrochemical reaction cell is 50 L / m 2 / min~500 L / m 2 / min; a water inlet unit for continuously supplying liquid water to the electrochemical reaction unit, and a water outlet of the water inlet unit is sealingly connected with a water inlet of the electrochemical reaction unit; a water outlet unit for collecting water discharged from the electrochemical reaction unit, and a water inlet of the water outlet unit is sealingly connected with a water outlet of the electrochemical reaction unit; the system further comprises a molecular oxygen compensation unit for compensating escaped oxygen molecules in the electrochemical reaction unit, and the molecular oxygen compensation unit comprises a compensation pipeline, one end of the compensation pipeline penetrates the inside of the closed electrochemical reaction cell and is located between the penetrating cathode plate and the penetrating anode plate; one end of the compensation pipeline is connected with a transfer bottle, the top of the transfer bottle is connected with an air pipe, a first one-way valve is installed on the surface of the air pipe, a second one-way valve is installed at the connection between the compensation pipeline and the transfer bottle, and a gas pressure gauge is installed on the top of an oxygen supply bottle; the penetrating cathode plate is a B / N co-doped high-purity carbon felt with a pore size of 50 μm, and the penetrating anode plate is a SnO2-Sb-Ti porous electrode with a pore size of 10 μm; the penetrating cathode plate and the penetrating anode plate are arranged in opposite parallel; the distance between the penetrating cathode plate and the penetrating anode plate is 0.2 cm-5 cm; the penetrating cathode plate is perpendicular to the water flow direction of the first flow guide pipe; and the penetrating cathode plate and the penetrating anode plate each comprise an electrode plate and an insulating frame fixed to the side of the electrode plate.

2. The halogen by-product abatement system of claim 1, wherein, A plurality of first perforations are formed in the side of the penetrating cathode plate, and a plurality of second perforations are formed in the side of the penetrating anode plate; the pore size of the first perforations is larger than that of the second perforations; and the first perforations and the second perforations are used for guiding water flow through the penetrating cathode plate and the penetrating anode plate.

3. The halogen byproduct abatement system of claim 1, wherein, Sealing flanges are installed at the connections between the second terminal post, the first terminal post and the closed electrochemical reaction cell, and the sealing flanges are made of insulating materials; a connection switch is installed on each of the second terminal post and the first terminal post.

4. The halogen byproduct abatement system of claim 1, wherein, The water inlet unit comprises a first pipeline and a water inlet pool, and the two ends of the first pipeline are respectively connected with the water inlet pool and the second flow guide pipe.

5. The halogen by-product abatement system of claim 4, wherein, The water outlet unit comprises a second pipeline, a measuring structure and a water outlet pool; the measuring structure is used for measuring the pressure and flow of water in the second pipeline; the two ends of the second pipeline are respectively connected with the water outlet pool and the first flow guide pipe; a booster pump is installed at the middle of the first pipeline and / or the second pipeline; and the water flow direction is from the penetrating anode plate to the penetrating cathode plate.

6. The halogen by-product abatement system of claim 5, wherein, The measuring structure comprises a water pressure gauge and a flow meter, and the water pressure gauge and the flow meter are respectively installed on the surface of the second pipeline.

7. A method of reducing control, characterized by, The method is applied to the halogen by-product reduction and control system as claimed in any one of claims 1-6, and comprises the following steps: introducing the sewage to be treated into the interior of the closed electrochemical reaction tank; closing the connecting switch on the first and second connecting posts, and connecting the through cathode plate and the through anode plate to the negative and positive poles of the direct current stabilized power supply, respectively; turning on the power supply of the lifting pump, and introducing the water in the water inlet tank into the closed electrochemical reaction tank, while the second pipeline introduces the treated water into the water outlet tank; after a certain reaction time, turning off the power supply of the through cathode plate and the through anode plate.

Images