System and method for reducing and controlling halogenated by-products

Abstract

The invention discloses a reduction and control system and method for halogenated byproducts in the technical field of water treatment.The reduction and control system comprises an electrochemical reaction unit, a water inlet unit and a water outlet unit, and the electrochemical reaction unit is used for conducting a cathode electro-Fenton reaction and reducing the halogenated byproducts generated in the electron transfer process; the water inlet unit is used for continuously supplying liquid water to the electrochemical reaction unit, and a water outlet of the water inlet unit is hermetically connected with a water inlet of the electrochemical reaction unit; and the water outlet unit is used for collecting water discharged by the electrochemical reaction unit. The coupled electrochemical water treatment system in a continuous cross-flow mode is constructed by combining a cross-flow anodic oxidation process with a cross-flow cathodic electro-Fenton reaction process driven by endogenous molecular oxygen, so that pollutants in water are efficiently removed under a low-potential condition, and the sewage treatment efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, in particular to a halogenated by-product reduction control system and a halogenated by-product reduction control method. Background Art

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

[0003] However, lowering the operating potential of the flow-through anode will inevitably reduce the amount of hydroxyl radicals generated at the flow-through anode, greatly reducing the wastewater treatment efficiency of the flow-through anode oxidation system, especially for some high ionization potential pollutants (such as atrazine, phenylacetic acid, and nitrobenzene). It is also difficult to effectively improve the treatment effect of such polluted water bodies. Summary of the invention

[0004] The purpose of the present invention is to provide a halogenated by-product reduction control system and a halogenated by-product reduction control method, which can effectively remove pollutants in water under low potential conditions and can reduce and control the generation of halogenated by-products. By combining a through-flow anodic oxidation process with a through-flow cathode electro-Fenton reaction process driven by endogenous molecular oxygen, a coupled electrochemical water treatment system with a continuous through-flow mode 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 object, the present invention provides the following technical solutions:

[0006] In a first aspect, a halogenated by-product reduction and control system is provided, comprising an electrochemical reaction unit, a water inlet unit, a water outlet unit and a molecular oxygen compensation unit, wherein the electrochemical reaction unit is used to generate a cathode electro-Fenton reaction and reduce the halogenated by-products generated during the electron transfer process; the water inlet unit is used to continuously supply liquid water to the electrochemical reaction unit, and the water outlet of the water inlet unit is sealed and connected to the water inlet of the electrochemical reaction unit; the water outlet unit is used to collect water discharged from the electrochemical reaction unit, and the water inlet of the water outlet unit is sealed and connected to the water 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 solution of the present invention: the electrochemical reaction unit comprises a closed electrochemical reaction cell and a DC regulated power supply, wherein a penetrating cathode plate and a penetrating anode plate are installed inside the closed electrochemical reaction cell;

[0008] Two opposite sides of the closed electrochemical reaction cell are respectively connected with a first flow guide pipe and a second flow guide pipe;

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

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

[0011] As a further solution of the present invention: the penetrating cathode plate and the penetrating anode plate are arranged relatively parallel, the spacing between the penetrating cathode plate and the penetrating anode plate is 0.2cm to 5cm, the penetrating cathode plate is perpendicular to the water diversion direction of the first guide tube, the penetrating cathode plate and the penetrating anode plate both include an electrode plate and an insulating frame fixed to the side of the electrode plate, and 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 solution of the present invention: a plurality of first through holes are formed through the sides of the two through cathode plates, a plurality of second through holes are formed through the sides of the through anode plates, the aperture of the first through holes is larger than the aperture of the second through holes, and both the first through holes and the second through holes are used to guide water flow through the through cathode plates and the through anode plates;

[0013] The material of the penetrating anode plate is one of SnO2-Sb-T i, RuO2-T i, β-PbO2-T i, Ti4O7, RuO2-I rO2-Ti, SnO2-Bi-T i, and BDD;

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

[0015] As a further solution of the present invention: the connection between the second terminal and the first terminal and the closed electrochemical reaction cell is provided with a sealing flange, and the sealing flange is made of an 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 on-off of the electrical connection path between the second terminal and the first terminal and the DC regulated power supply, so as to improve the start-up efficiency of the electrochemical reaction in the closed electrochemical reaction cell.

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

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

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

[0020] As a further solution of the present invention: the system further comprises a molecular oxygen compensation unit, the molecular oxygen compensation unit is used to compensate for oxygen molecules escaping from the electrochemical reaction unit, the molecular oxygen compensation unit comprises a compensation pipe, one end of the compensation pipe passes through 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 pipe is connected to the transfer bottle, the top of the transfer bottle passes through the connecting trachea, a first one-way valve is installed on the surface of the trachea, a second one-way valve is installed at the connection between the compensation pipe and the transfer bottle, and a pressure gauge is installed on the top of the oxygen supply bottle.

[0022] In a second aspect, a reduction control method is also provided, which is applied to the reduction control system of the halogenated byproducts as described in the above scheme, and the method comprises:

[0023] Introducing the sewage to be treated into the interior of the closed electrochemical reaction cell;

[0024] Closing the connection switch located on the first terminal and the second terminal, connecting the penetrating cathode plate and the penetrating anode plate to the negative electrode and the positive electrode of the DC regulated power supply respectively;

[0025] Turn on the power of the lifting pump to pass the water in the water inlet tank into the closed electrochemical reaction tank, and at the same time, the second pipeline passes the treated water into the water outlet tank;

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

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention couples the through-flow anodic oxidation process and relies on endogenous molecular oxygen to drive the through-flow cathode electro-Fenton reaction. It can treat the endogenous oxygen generated by electrolyzing water at the penetrating anode during the operation of the system, and transmit the endogenous oxygen to the penetrating cathode along with the water flow, and convert it into hydroxyl free radicals through the electro-Fenton reaction process, thereby compensating for the shortcoming of insufficient free radical generation due to the lowered potential at the penetrating anode, and enabling the entire system to achieve high free radical yield at a low potential.

[0029] 2. The present invention can significantly weaken the reaction process between halogen ions in sewage and electrodes by adopting low potential conditions, effectively inhibit the generation and further conversion of active halogens, and thus significantly reduce the generation of inorganic and organic halogenated by-products.

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

[0031] 4. The present invention can effectively remove pollutants in water under low potential conditions, consumes less electrical energy, and can reduce and control the generation of halogenated by-products. By combining the through-flow anodic oxidation process with the through-flow cathode electro-Fenton reaction process driven by endogenous molecular oxygen, a coupled electrochemical water treatment system with a continuous through-flow mode is constructed, which achieves efficient removal of pollutants in water under low potential conditions and improves the treatment efficiency of sewage, especially for the removal of high ionization potential pollutants. The through-flow cathode reaction process of the present invention also has the function of electro-reducing halogenated by-products, which effectively realizes the reduction control of halogenated by-products in the water treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1A structural diagram of the electrochemical system for reducing and controlling the generation of halogenated byproducts of the present invention;

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

[0034] Figure 3 A front view of a through cathode plate of the present invention;

[0035] Figure 4 It is a pollutant removal rate result diagram of the first embodiment, the second embodiment and the third embodiment of the present invention;

[0036] Figure 5 The first embodiment, the second embodiment, and the third embodiment of the present invention have different C l - Results of the production of various halogenated disinfection by-products at different concentrations;

[0037] Figure 6 It is a pollutant removal rate result diagram of different electrochemical systems in the fifth embodiment and the second embodiment of the present invention;

[0038] Figure 7 The graphs are the results of the generation of hydroxyl radicals in different electrochemical systems in the sixth embodiment, the seventh embodiment and the fourth embodiment of the present invention;

[0039] Figure 8 It is a result diagram of the generation amount of various halogenated disinfection by-products in different electrochemical systems in the eighth embodiment and the second embodiment of the present invention;

[0040] Fig. 9 The figure is a flowchart of the method of the present invention.

[0041] In the figure: 1. Penetrate the cathode plate; 2. Penetrate the anode plate; 3. DC regulated power supply; 4. Lifting pump; 5. Water inlet tank; 6. Water outlet tank; 7. Sealing flange; 8. First terminal; 9. Second terminal; 10. First flow guide tube; 11. Second flow guide tube; 12. Second pipeline; 13. Closed electrochemical reaction cell; 14. First pipeline; 15. Water pressure gauge; 16. Flow meter; 17. Insulation frame; 18. Connecting switch; 19. Compensating pipeline; 191. Second one-way valve; 20. Transfer bottle; 21. Air pipe; 22. First one-way valve; 23. Oxygen supply bottle. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] See also Figure 1 - Figure 3 The present invention discloses a halogenated byproduct reduction and control system, comprising 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 the halogenated byproducts generated in the electron transfer process; the water inlet unit is used for continuously supplying liquid water to the electrochemical reaction unit, and the water outlet of the water inlet unit is sealed and connected to the water inlet of the electrochemical reaction unit; the water outlet unit is used for collecting water discharged from the electrochemical reaction unit, and the water inlet of the water outlet unit is sealed and connected to the water outlet of the electrochemical reaction unit.

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

[0045] Two opposite sides of the closed electrochemical reaction cell 13 are respectively connected with a first flow guide tube 10 and a second flow guide tube 11;

[0046] A second terminal 8 is fixed on the side of the penetrating cathode plate 1, and the second terminal 8 is connected to the negative electrode of the DC voltage-stabilized power supply 3. A first terminal 9 is fixed on the side of the penetrating anode plate 2, and the first terminal 9 is connected to the positive electrode of the DC voltage-stabilized power supply 3. By applying a low potential to drive the system to operate, the reaction process between the halide ions in the sewage and the electrode is greatly reduced, and the halide ions are effectively inhibited from further conversion to active halogen at the anode and the active halogen, thereby significantly reducing the generation of inorganic and organic halogenated by-products, which can effectively avoid the Cl in the water matrix. - At high potential, it reacts with the electrode to generate ClO3 - and ClO4 - ;

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

[0048] Preferably, the penetrating cathode plate 1 and the penetrating anode plate 2 are arranged relatively parallel, the spacing between the penetrating cathode plate 1 and the penetrating anode plate 2 is 0.2 cm to 5 cm, the penetrating cathode plate 1 is perpendicular to the water diversion direction of the first guide tube 10, the penetrating cathode plate 1 and the penetrating anode plate 2 both include an electrode plate and an insulating frame 17 fixed to the side of the electrode plate, and 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 penetrated with a plurality of first perforations, and the sides of the penetrating anode plates 2 are penetrated with a plurality of second perforations, the aperture of the first perforation is larger than the aperture of the second perforation, the aperture of the first perforation is 30 μm to 50 μm, and the aperture of the second perforation is 5 μm to 10 μm, which can facilitate the excess molecular oxygen O2 generated by the penetrating anode plate 2 to pass smoothly through the penetrating cathode plate 1, and avoid the penetrating cathode plate 1 intercepting and agglomerating the excess molecular oxygen O2 and affecting the stable operation of the reaction system, the first perforation and the second perforation are both used to guide the water flow to pass through the penetrating cathode plate 1 and the penetrating anode plate 2, the first perforation and the second perforation are arranged at intervals in the direction from the penetrating anode plate 2 to the penetrating cathode plate 1, and a coupled electrochemical water treatment system with a continuous flow mode is constructed, and the water flow direction flows from the penetrating anode plate 2 to the penetrating cathode plate 1, considering that the water flow direction is conducive to the endogenous oxygen generated by the electrolysis of water through the penetrating anode plate 2 to be transmitted to the penetrating cathode plate 1 with the water flow to undergo a 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 material has good direct electron transfer DET efficiency and oxygen evolution performance, and 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 a four-electron oxidation reaction of H2O. At the same time, the penetrating anode plate 2 made of the above material degrades pollutants through a direct electron transfer process DET during the anodic oxidation process;

[0051] The material of the penetrating cathode plate 1 is one of B / N (boron / nitrogen) co-doped high-purity carbon felt, B / N (boron / nitrogen) co-doped carbon nanotubes, a filter membrane stacked with graphene materials, sulfur-doped Fe2O3, Co3O4, and Cu2O. Considering that in the cathode electro-Fenton reaction process, the penetrating cathode plate 1 of the above material has high selectivity and reaction efficiency for the two-electron reduction reaction of O2 to generate hydrogen peroxide H2O2. At the same time, the B / N (boron / nitrogen) co-doped porous material can not only provide abundant active centers, but also effectively improve the specific surface area and porous structure, and has a high efficiency in activating hydrogen peroxide H2O2 to generate hydroxyl radicals ·OH. In the cathode electro-reduction dehalogenation process, the penetrating cathode plate 1 of the above material has a large specific surface area and rich pore structure. Their high electron conductivity can be used as an electron transmission channel to promote the reduction reaction of halogenated byproducts on the cathode surface.

[0052] Preferably, the connection between the second terminal 8 and the first terminal 9 and the closed electrochemical reaction cell 13 is provided with a sealing flange 7, and the sealing flange 7 is made of an insulating material;

[0053] A connecting switch 18 is installed on the second terminal 8 and the first terminal 9 respectively. The two connecting switches 18 are used to control the on-off of the electrical connection path between the second terminal 8 and the first terminal 9 and the DC regulated power supply 3, so as to improve the starting 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 , and two ends of the first pipe 14 are connected to the water inlet pool 5 and the second flow guide pipe 11 respectively.

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

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

[0057] Preferably, the system further comprises a molecular oxygen compensation unit, the molecular oxygen compensation unit is used to compensate for oxygen molecules escaping from the electrochemical reaction unit, the molecular oxygen compensation unit comprises a compensation pipe 19, one end of the compensation pipe 19 passes through 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 comprises a compensation pipe 19, one end of the compensation pipe 19 passes through 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 transport bottle 20, the top of the transport bottle 20 passes through the connecting 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 transport bottle 20, and a pressure gauge is installed on the top of the oxygen supply bottle 23.

[0059] The process operation of the electrolysis system of the present invention includes: the sewage to be treated is powered by a lifting pump 4, and enters the closed electrochemical reaction cell 13 from the water inlet tank 5 through the first pipeline 14 and the second guide pipe 11 on the side of the penetrating anode plate 2. After the sewage to be treated fills the closed electrochemical reaction cell 13, it flows out from the outlet on the side of the penetrating cathode plate 1, enters the water outlet tank 6 through the second pipeline 12 to form a closed loop, and connects the DC voltage-stabilized power supply 3 to start electrochemical treatment of the sewage to be treated. H2O adsorbed on the surface of the penetrating anode plate 2 undergoes a four-electron oxidation reaction to generate molecular oxygen O2, and at the same time, the penetrating anode plate 2 undergoes a direct electron transfer process DET to degrade pollutants, and the molecular oxygen O2 is transported to the penetrating cathode plate 1 with the convection transmission of the treated water sample to undergo a two-electron reduction reaction of O2 to generate hydrogen peroxide H2O2, and then the B / N (boron / nitrogen) co-doped catalyst loaded on the penetrating cathode plate 1 activates the hydrogen peroxide H2O2 to generate hydroxyl radicals OH, and the hydroxyl radicals OH participate in the free radical oxidation reaction to degrade pollutants. At the same time, the halogenated byproducts generated by penetrating the anode can be reduced by penetrating the cathode. The pollutant removal effect is fully enhanced while the generation of halogenated disinfection by-products is reduced.

[0060] During the process operation, the sewage to be treated continuously enters the closed electrochemical reaction tank 13 from the water inlet tank 5, continuously reacts in the closed electrochemical reaction tank 13 in the form of a continuous flow, and is then discharged to the water outlet tank 6, and the pollutants are finally degraded from the sewage to be treated.

[0061] During the operation of the system, the polluted sewage in the water inlet tank 5 enters the closed electrochemical reaction tank 13 through the water inlet of the closed electrochemical reaction tank 13 under the action of the lifting pump 4. The polluted sewage first passes through the penetrating anode plate 2. After the polluted sewage fills the closed electrochemical reaction tank 13, the system forms a closed loop and connects to the DC regulated power supply 3. The penetrating anode plate 2 undergoes a direct electron transfer process DET, and the penetrating anode plate 2 generates molecular oxygen O2. The molecular oxygen O2 is transported to the penetrating cathode plate 1 to undergo a two-electron reduction reaction of O2 to generate hydrogen peroxide H2O2. The B / N co-doped catalyst loaded on the penetrating cathode plate 1 activates the hydrogen peroxide H2O2 to generate hydroxyl radicals ·OH. The hydroxyl radicals ·OH participate in the free radical oxidation reaction to degrade pollutants. At the same time, the halogenated by-products generated by penetrating the anode can be reduced at the penetrating cathode, achieving the comprehensive enhancement of the pollutant removal effect while reducing the generation of halogenated disinfection by-products. The purified sewage passes through the penetrating cathode plate 1 and flows out from the outlet into the water outlet tank 6.

[0062] The working principle of the halogenated byproduct reduction control system of the present invention is:

[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] At the same time, the direct electron transfer process DET occurs through the surface of the anode plate 2 to degrade pollutants;

[0065] Reaction 2: The molecular oxygen O2 generated at the anode is transported to the cathode plate 1 by the convection of the treated water sample, and a two-electron reduction reaction of O2 occurs 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, which participate in free radical oxidation reactions to degrade pollutants. At the same time, the halogenated byproducts generated by penetrating the 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 is to test the - At the concentration, the pollutant removal effect of an electrochemical system for reducing the generation of halogenated by-products and the effect of reducing the generation of halogenated disinfection by-products were verified.

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

[0073] Specifically, the plate spacing between the penetrating anode plate 2 and the penetrating cathode plate 1 is 2 cm, and the water flow rate is set to 240 L / m 2 / min, the current density was set to 15mA / cm 2 The atrazine concentration of the samples was detected and analyzed at 0, 5, 10, 20, 30, 45, and 60 minutes of electrolysis. The concentrations of various halogenated disinfection by-products of the samples were detected and analyzed at 60 minutes of electrolysis. The experiment was repeated many times to reduce the impact of errors.

[0074] Specifically, after the electrolysis system had been running for 60 min, the final removal rate of atrazine was stabilized at more than 90%, and the concentrations of inorganic and organic halogenated disinfection by-products were both low.

[0075] Second embodiment:

[0076] This embodiment is to test the - At the concentration, the pollutant removal effect of an electrochemical system for reducing the generation of halogenated by-products and the effect of reducing the generation of halogenated disinfection by-products were verified.

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

[0078] Specifically, the plate spacing between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow rate is set to 320 L / m 2 / min, the current density was set to 10mA / cm 2 The atrazine concentration of the samples was detected and analyzed at 0, 5, 10, 20, 30, 45, and 60 minutes of electrolysis. The concentrations of various halogenated disinfection by-products of the samples were detected and analyzed at 60 minutes of electrolysis. The experiment was repeated many times to reduce the impact of errors.

[0079] Specifically, after the electrolysis system had been running for 60 minutes, the final removal rate of atrazine was stabilized at more than 95%, and the concentrations of inorganic and organic halogenated disinfection by-products were the lowest.

[0080] Third embodiment:

[0081] This embodiment is to test the - At the concentration, the pollutant removal effect of an electrochemical system for reducing the generation of halogenated by-products and the effect of reducing the generation of halogenated disinfection by-products were verified.

[0082] Specifically, simulated sewage was used as the treatment object, the dosage of atrazine was 10 μmol / L, the solution electrolyte was a NaCl solution with a concentration of 10 mM, the penetrating cathode plate 1 used sulfur-doped Fe2O3 with a pore size of 40 μm, and the penetrating anode plate 2 used a β-PbO2-T i 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 rate is set to 160 L / m 2 / min, the current density was set to 10mA / cm 2The atrazine concentration of the samples was detected and analyzed at 0, 5, 10, 20, 30, 45, and 60 minutes of electrolysis. The concentrations of various halogenated disinfection by-products of the samples were detected and analyzed at 60 minutes of electrolysis. The experiment was repeated many times to reduce the impact of errors.

[0084] Specifically, after the system had been running for 60 min, the final removal rate of atrazine was stabilized at more than 85%, and the concentrations of both inorganic and organic halogenated disinfection by-products were low.

[0085] Fourth embodiment:

[0086] The present embodiment aims to test 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 solution electrolyte is selected from 100 mM potassium dihydrogen phosphate solution + 20 μM benzoic acid solution.

[0088] Specifically, the through cathode plate 1 uses 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 plate spacing between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow rate is set to 320 L / m 2 / min, the current density was set to 10mA / cm 2 The hydroxyl radical concentration of the samples was detected and analyzed at 0, 5, 10, 20, 30, 45, and 60 minutes after electrolysis, and the experiment was repeated many times to reduce the influence of errors.

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

[0091] Fifth embodiment:

[0092] This embodiment uses an electrochemical device using a single flow-through anodic oxidation technology for comparison with the second embodiment.

[0093] Specifically, simulated sewage was used as the treatment object, the dosage of atrazine was set to 10 μmol / L, the solution electrolyte was selected as a NaCl solution with a concentration of 5 mM, a penetrating cathode plate 1 with a porous structure, a material of stainless steel, and a pore size of 50 μm was used, and the penetrating anode plate 2 used a SnO2-Sb-Ti porous electrode with a pore size of 10 μm consistent with the second embodiment.

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

[0095] Specifically, after the system had been running for 60 min, the final removal rate of atrazine was stabilized at about 15%.

[0096] From the above, it can be seen that the pollutant removal rate of the fifth embodiment is much lower than that of the second embodiment. This is because the hydroxyl radical production of the fifth embodiment is insufficient under low potential conditions, and it can only rely on the direct electron transfer process DET of the anode to react with the pollutants, which not only has low degradation efficiency but also cannot completely oxidize pollutants with high ionization potential IP. The second embodiment not only utilizes the direct electron transfer process DET of the anode, but also utilizes the through-flow cathode electro-Fenton reaction process driven by endogenous molecular oxygen, which successfully makes up for the shortcoming of insufficient free radical generation due to the lower potential of the penetrating anode in comparative example 1, so that the entire system can achieve a higher free radical production by operating at a low potential, which improves the pollutant degradation efficiency and can effectively remove pollutants with high ionization potential IP.

[0097] Sixth embodiment:

[0098] The electrochemical device of this embodiment using the single flow-through anodic oxidation technology is compared with the fourth embodiment.

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

[0100] Specifically, the sixth embodiment adopts a porous structure, stainless steel, and a through cathode plate 1 with a pore size of 50 μm, and the through anode plate 2 adopts a SnO2-Sb-Ti porous electrode with a pore size of 10 μm consistent with the fourth embodiment.

[0101] Specifically, the plate spacing between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow rate is set to 320 L / m 2 / min, the current density was set to 10mA / cm 2 The hydroxyl radical concentration of the samples was detected and analyzed at 0, 5, 10, 20, 30, 45, and 60 minutes after electrolysis, and the experiment was repeated many times to reduce the influence of errors.

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

[0103] Seventh embodiment:

[0104] The electrochemical device of this embodiment using the single flow-through anodic oxidation technology is compared with the fourth embodiment.

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

[0106] Specifically, a porous structure, stainless steel, and 50 μm pore size penetrating cathode plate 1 is used, and a penetrating anode plate 2 is a SnO2-Sb-Ti porous electrode with a pore size of 10 μm consistent with the fourth embodiment.

[0107] Specifically, the plate spacing between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow rate is set to 320 L / m 2 / min, the current density was set to 30mA / cm 2 The hydroxyl radical concentration of the samples was detected and analyzed at 0, 5, 10, 20, 30, 45, and 60 minutes after electrolysis, and the experiment was repeated many times to reduce the influence of errors.

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

[0109] It can be seen that the hydroxyl radical production of the sixth embodiment is much lower than that of the fourth embodiment. This is because under low potential drive, the sixth embodiment relies solely on penetrating the anode to electrolyze water, resulting in insufficient hydroxyl radical production, while the fourth embodiment utilizes the endogenous oxygen generated by penetrating the anode to electrolyze water and is transmitted to the penetrating cathode with the water flow, and is converted into hydroxyl radicals through the electro-Fenton reaction process, so that the entire system can be operated at a low potential to achieve a higher free radical production. 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 large amount of hydroxyl radical production at a low potential, thereby ensuring the removal of pollutants and reducing power consumption.

[0110] Eighth embodiment:

[0111] This embodiment uses an electrochemical device using a single flow-through anodic oxidation technology for comparison with the second embodiment.

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

[0113] Specifically, a porous structure, stainless steel, and 50 μm pore size penetrating cathode plate 1 is used, and a penetrating anode plate 2 is a SnO2-Sb-Ti porous electrode with a pore size of 10 μm, which is consistent with the pore size in the second embodiment.

[0114] Specifically, the plate spacing between the penetrating anode plate 2 and the penetrating cathode plate 1 is 1 cm, and the water flow rate is set to 320 L / m 2 / min, the current density was set to 10mA / cm 2 , sampling was performed to detect and analyze the concentrations of various halogenated disinfection by-products in the samples at 60 minutes of electrolysis, and the experiment was repeated several times to reduce the impact of errors.

[0115] Specifically, after the system had been running for 60 min, the concentrations of various halogenated disinfection by-products were relatively high.

[0116] It can be seen that the concentrations of various halogenated disinfection by-products 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 halogen ions at the anode to active halogen and further conversion of active halogen, effectively reducing the generation of halogenated by-products, compared with this embodiment, the second embodiment also effectively utilizes the electrochemical cathode reduction dehalogenation reaction, and the halogenated by-products generated by penetrating the anode are reduced at the penetrating cathode, thereby strengthening the control of the reduction of halogenated disinfection by-products.

[0117] like Fig. 9 As shown, a reduction control method is also provided, which is applied to the reduction control system of the halogenated byproducts in the above scheme, and the method comprises the following steps:

[0118] S1: introducing the wastewater to be treated into the closed electrochemical reaction cell 13;

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

[0120] S3: Turn on the power of the lifting pump 4 to pass the water in the water inlet pool 5 into the closed electrochemical reaction pool 13, and at the same time, the second pipe 12 passes the treated water into the water outlet pool 6;

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

[0122] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can replace or change the technical solution and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A halogenated byproduct reduction and control system, characterized in that: include: An electrochemical reaction unit, wherein the electrochemical reaction unit is used to generate a cathode electro-Fenton reaction and reduce halogenated byproducts generated during the electron transfer process; A water inlet unit, the water inlet unit is used to continuously supply liquid water to the electrochemical reaction unit, and the water outlet of the water inlet unit is sealed and connected to the water inlet of the electrochemical reaction unit; A water outlet unit is used to collect water discharged from the electrochemical reaction unit, and a water inlet of the water outlet unit is sealed and connected to a water outlet of the electrochemical reaction unit.

2. The halogenated byproduct reduction and control system according to claim 1, characterized in that: The electrochemical reaction unit comprises a closed electrochemical reaction cell and a DC regulated power supply, wherein 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 is fixed on the side of the penetrating cathode plate, and the second terminal is connected to the negative electrode of the DC regulated power supply. A first terminal is fixed on the side of the penetrating anode plate, and the first terminal is connected to the positive electrode of the DC regulated power supply. The current density of the DC regulated power supply is 5 mA / cm 2 ~20mA / cm 2 The water flow rate in the closed electrochemical reaction cell is 50L / m 2 / min~500L / m 2 / min.

3. The halogenated byproduct reduction and control system according to claim 2, characterized in that: The penetrating cathode plate and the penetrating anode plate are arranged relatively parallel, the spacing between the penetrating cathode plate and the penetrating anode plate is 0.2cm to 5cm, the penetrating cathode plate is perpendicular to the water diversion direction of the first guide pipe, and the penetrating cathode plate and the penetrating anode plate both include an electrode plate and an insulating frame fixed on the side of the electrode plate.

4. The halogenated byproduct reduction control system according to claim 3, characterized in that: The sides of the two through-cathode plates are penetrated by a plurality of first through-holes, and the sides of the through-anode plates are penetrated by a plurality of second through-holes. The aperture of the first through-holes is larger than the aperture of the second through-holes. Both the first through-holes and the second through-holes are used to guide water flow through the through-cathode plates and the through-anode plates.

5. The halogenated byproduct reduction and control system according to claim 2, characterized in that: The connection between the second terminal and the first terminal and the closed electrochemical reaction cell is provided with a sealing flange, which is made of an insulating material; A connection switch is respectively installed on the second binding post and the first binding post.

6. The halogenated byproduct reduction and control system according to claim 3, characterized in that: The water inlet unit comprises a first pipe and a water inlet pool, and two ends of the first pipe are respectively connected to the water inlet pool and the second guide pipe.

7. The halogenated byproduct reduction and control system according to claim 6, characterized in that: The water outlet unit includes a second pipeline, a measuring structure and a water outlet pool. The measuring structure is used to measure the pressure and flow of the water in the second pipeline. The two ends of the second pipeline are respectively connected to the water outlet pool and the first guide pipe. The lifting pump is installed in the middle of the first pipeline and / or the second pipeline. The water flow direction is from penetrating the anode plate to penetrating the cathode plate.

8. The halogenated byproduct reduction and control system according to claim 7, characterized in that: The measuring structure comprises a water pressure gauge and a flow meter, and the water pressure gauge and the flow meter are respectively installed through the surface of the second pipeline.

9. The halogenated byproduct reduction and control system according to claim 1, characterized in that: The system further comprises a molecular oxygen compensation unit, which is used to compensate for oxygen molecules escaping from the electrochemical reaction unit. The molecular oxygen compensation unit comprises 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; One end of the compensation pipe is connected to the transfer bottle, the top of the transfer bottle passes through the connecting trachea, a first one-way valve is installed on the surface of the trachea, a second one-way valve is installed at the connection between the compensation pipe and the transfer bottle, and a pressure gauge is installed on the top of the oxygen supply bottle.

10. A control reduction method, characterized in that: The method applied to the halogenated byproduct reduction control system according to any one of claims 1 to 9 comprises: Introducing the sewage to be treated into the interior of the closed electrochemical reaction cell; Closing the connection switch located on the first terminal and the second terminal, connecting the penetrating cathode plate and the penetrating anode plate to the negative electrode and the positive electrode of the DC regulated power supply respectively; Turn on the power of the lifting pump to pass the water in the water inlet tank into the closed electrochemical reaction tank, and at the same time, the second pipeline passes the treated water into the water outlet tank; After a certain reaction time, the power is cut off to the cathode plate and the anode plate.

Images