Integrated flow cathode dehalogenation wastewater treatment system and wastewater treatment method

Abstract

The present invention proposes an integrated flow cathode dehalogenation sewage treatment system and sewage treatment method, the system includes a screening cathode, an anode and a shell which are sequentially arranged from the inside to the outside; the interior of the screening cathode is in a cavity shape and forms a cathode chamber; there is a spacing between the screening cathode and the anode and between the anode and the shell; a plurality of movable particle electrodes are arranged in the cathode chamber, the particle electrodes undergo cathode polarization under the action of an electric field, and produce atomic hydrogen for dehalogenating halogenated organic pollutants in sewage; the screening cathode is a porous material, the screening cathode screens the sewage after the reaction, and intercepts the particle electrodes. The screening cathode of the present invention adopts a porous electrode material, and during use, the cathode has the functions of both a cathode current collector and a particle electrode sifter, which can block the particle electrodes in the cathode chamber, reducing the amount of particle electrodes used in the system as a whole.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to an integrated flow cathode dehalogenation sewage treatment system and a sewage treatment method. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] Atomic hydrogen-mediated electrochemical reduction technology relies on the strong reducing atomic hydrogen (reduction potential of -2.1 V vs RHE) generated at the cathode interface, which can selectively break carbon-halogen bonds and achieve dehalogenation of halogenated organic pollutants in water. It is considered to be a new and effective harmless treatment method for halogenated organic pollution in water. Among them, the new mobile cathode electrochemical reduction system relies on the full mixing of particle electrodes and the main solution to significantly enhance the mass transfer process between atomic hydrogen generated at the electrode interface and halogenated organic pollutants, thereby significantly improving the dehalogenation activity and sewage treatment efficiency of the atomic hydrogen-mediated electrochemical system, showing great application prospects in the field of wastewater treatment containing halogenated organic pollutants.

[0004] However, the addition of a large number of particle electrodes to the main solution of the flow cathode electrochemical reduction system will greatly increase the amount of particles used, and the screening process after the use of the particle electrodes also increases the complexity of the reaction system, thereby increasing investment and operating costs. Therefore, from the perspective of wastewater treatment and resource economy, it is urgent to further improve and develop new and efficient flow cathode reaction systems. Summary of the invention

[0005] In view of the shortcomings of the current flowing cathode electrochemical dehalogenation wastewater treatment system, the present invention proposes an integrated flowing cathode dehalogenation wastewater treatment system and a wastewater treatment method to solve the problem that when the existing flowing cathode system treats wastewater, the amount of particle electrodes is large and an additional screening system is required, resulting in increased investment and operating costs.

[0006] The technical solution of the present invention is achieved in this way:

[0007] An integrated flow cathode dehalogenation wastewater treatment system, comprising:

[0008] A screening cathode coupled flowing electrode electrochemical reduction reactor comprises a screening cathode, an anode and a shell which are sequentially sleeved from the inside to the outside; the interior of the screening cathode is in a cavity shape and forms a cathode chamber; there is a distance between the screening cathode and the anode and between the anode and the shell; a plurality of movable particle electrodes are arranged in the cathode chamber, and the particle electrodes are cathodically polarized under the action of an electric field to generate atomic hydrogen for dehalogenating halogenated organic pollutants in sewage; the screening cathode is a porous material, and the screening cathode screens the sewage after the reaction and intercepts the particle electrodes;

[0009] A power supply assembly is electrically connected to the screening cathode and the anode respectively;

[0010] A sewage input component is connected to the cathode chamber and is used to input sewage into the cathode chamber;

[0011] The sewage discharge component is used to discharge the sewage after the reaction.

[0012] To further optimize the technical solution, the shell is in the shape of a cylinder that penetrates from top to bottom; the screening cathode-coupled flowing electrode electrochemical reduction reactor also includes an upper sealing flange sealed at the top end of the shell and a lower sealing flange sealed at the bottom end of the shell.

[0013] To further optimize the technical solution, the upper sealing flange is provided with a water inlet and a water outlet connected to the cathode chamber, and the water outlet is connected to the sewage discharge component.

[0014] To further optimize the technical solution, the anode is made of a grid-shaped metal or metal oxide material, and a grid is provided on the anode to filter sewage and allow sewage to pass through; a holding cavity for holding purified sewage is formed between the anode and the shell, and the holding cavity is connected to the water outlet.

[0015] To further optimize the technical solution, the porous material is made of Ti or Cu or stainless steel or metal oxide.

[0016] To further optimize the technical solution, the particle electrode is a reactive solid powder with a particle size range of 1-1000 um and its surface modified or modified derivatives; the particle electrode has a large specific surface area.

[0017] To further optimize the technical solution, the dosage of the particle electrode is set according to the effective volume of the cathode chamber; the dosage of the particle electrode is 1-20 g / L.

[0018] To further optimize the technical solution, when the particle electrode performs solid-liquid separation on the inner surface of the cathode chamber, a stack is formed on the surface of the screening cathode to produce a filter cake; the filter cake is used to improve the interception efficiency of the screening cathode for the particle electrode and the pollutant removal efficiency.

[0019] Further optimization of the technical solution may include one or more of the following:

[0020] The power supply component is a DC regulated power supply or a constant potential instrument;

[0021] The sewage input assembly includes a water storage tank, a sewage input pipeline and a lifting pump, one end of the sewage input pipeline is connected to the water storage tank, the other end of the sewage input pipeline is connected to the cathode chamber, and the lifting pump is arranged on the sewage input pipeline;

[0022] The sewage discharge assembly includes a sewage output pipeline;

[0023] The cathode chamber is provided with a stirring device for ensuring that the particle electrodes are in a flowing and mixing state in the cathode chamber, so as to improve the mass transfer efficiency of the pollutants.

[0024] A sewage treatment method, which is based on the integrated flow cathode dehalogenation sewage treatment system, comprises the following steps:

[0025] The sewage is introduced into the cathode chamber of the screening cathode coupled flow electrode electrochemical reduction reactor through the sewage input assembly;

[0026] The particle electrodes in the cathode chamber are cathodically polarized under the action of the electric field, generating atomic hydrogen, which dehalogenates the halogenated organic pollutants in the sewage.

[0027] The wastewater after the reaction is screened by the screening cathode, and the particle electrode is retained in the cathode chamber to continue the reaction;

[0028] The purified sewage is discharged from the cathode chamber and then discharged through the sewage discharge component.

[0029] By adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0030] The screening cathode of the present invention adopts a porous electrode material. During use, the cathode serves as both a cathode current collector and a particle electrode sifter, and can block the particle electrodes in the cathode chamber to avoid waste of the particle electrodes due to wastewater flowing out of the system, thereby ensuring that the particle electrodes can be repeatedly recycled, thereby reducing the overall particle electrode usage of the system, and there is no need to add an additional screening system to recycle the particle electrodes.

[0031] The particle electrode is only added in the cathode chamber, and its dosage is determined according to the experiment, generally 1-20 g / L. The particle electrode is in a flowing mixed state in the cathode chamber under the action of mechanical stirring to improve the mass transfer efficiency of pollutants.

[0032] During the operation of the reaction system, wastewater containing halogenated organic pollutants is continuously introduced into the reaction system. The particle electrodes undergo cathodic polarization under the action of the electric field, generating atomic hydrogen for dehalogenation of halogenated organic pollutants in the wastewater. The reacted wastewater is screened by the cathode current collector, and the particle electrodes are retained in the cathode chamber to continue the reaction. The purified water is discharged from the reaction system. At the same time, when the particle electrodes perform solid-liquid separation on the inner surface of the chamber, they can form a stack on the surface of the current collector, producing a filter cake of a certain thickness, further improving the interception efficiency and efficient removal of pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 It is a structural schematic diagram of a screening cathode coupled flowing electrode electrochemical reduction reactor of an integrated flowing cathode dehalogenation wastewater treatment system of the present invention;

[0035] Figure 2 It is a schematic diagram of the internal structure of a screening cathode coupled flowing electrode electrochemical reduction reactor of an integrated flowing cathode dehalogenation wastewater treatment system of the present invention;

[0036] Figure 3 It is a structural schematic diagram of an integrated flow cathode dehalogenation wastewater treatment system of the present invention;

[0037] Figure 4 This is a pollutant removal effect diagram of an integrated flow cathode dehalogenation wastewater treatment system of the present invention when degrading trichloroacetic acid;

[0038] Figure 5 This is a pollutant removal effect diagram of the integrated mobile cathode dehalogenation wastewater treatment system of the present invention for degrading 2,4-dichlorophenol.

[0039] Wherein: 1. Sealed flange, 2. Wiring wire, 3. Water inlet, 4. Water outlet, 5. Screening cathode, 6. Anode, 7. Shell, 8. Stirring device, 9. Particle electrode, 10. Screening cathode coupled flow electrode electrochemical reduction reactor, 11. Power supply component, 12. Water storage tank, 13. Lifting pump, 14. Sewage input pipeline, 15. Sewage output pipeline. DETAILED DESCRIPTION

[0040] 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.

[0041] Example 1

[0042] An integrated flow cathode dehalogenation wastewater treatment system, combined with Figures 1 to 3 As shown, it includes a screening cathode-coupled flow electrode electrochemical reduction reactor 10, a power supply component, a sewage input component and a sewage discharge component.

[0043] The screening cathode coupled flowing electrode electrochemical reduction reactor 10 comprises a screening cathode 5, an anode 6 and a housing 7 which are sequentially sleeved from the inside to the outside.

[0044] The interior of the screening cathode 5 is hollow and forms a cathode chamber. A plurality of movable particle electrodes 9 are arranged in the cathode chamber. The particle electrodes 9 are cathodically polarized under the action of the electric field to generate atomic hydrogen for dehalogenating halogenated organic pollutants in the sewage. The screening cathode 5 screens the sewage after the reaction and intercepts the particle electrodes.

[0045] The housing 7 is used to collect the water and provide a closed environment.

[0046] The power supply assembly 11 is electrically connected to the screening cathode 5 and the anode through the wiring conductor 2. The power supply assembly is a DC regulated power supply or a constant potential instrument, which provides stable energy for the system to promote the electrochemical reaction.

[0047] The sewage input assembly is connected to the cathode chamber and is used to input sewage into the cathode chamber. The sewage input assembly includes a water tank 12, a sewage input pipeline 14 and a lift pump 13. One end of the sewage input pipeline 14 is connected to the water tank 12, and the other end of the sewage input pipeline 14 is connected to the cathode chamber. The lift pump 13 is arranged on the sewage input pipeline 14, and the lift pump promotes the solution to flow in the system. When the lift pump 13 in this embodiment is in operation, the sewage in the water tank 12 is pumped into the cathode chamber through the sewage input pipeline 14.

[0048] The sewage discharge assembly is used to discharge the sewage after the reaction. The sewage discharge assembly includes a sewage output pipeline 15, and a valve and other structures can also be set on the sewage output pipeline 15.

[0049] The outer shell is cylindrical and penetrates from top to bottom. The screening cathode coupled flow electrode electrochemical reduction reactor 10 also includes a sealing flange 1, which is divided into an upper sealing flange sealed at the top of the shell and a lower sealing flange sealed at the bottom of the shell. The upper sealing flange and the lower sealing flange are locked and positioned by connecting bolts. The sealing flange 1 provides a sealing effect for the device and provides a certain structural strength; the screening cathode 5 is a cathode current collector and completes the solid-liquid separation of the "particle electrode-water" heterogeneous system.

[0050] The upper sealing flange is provided with a water inlet 3 and a water outlet 4 which are connected to the cathode chamber, and the water outlet 4 is connected to the sewage discharge assembly.

[0051] It should be noted that the sealing flange and the outer shell are both made of insulating materials.

[0052] The anode is made of a mesh-shaped metal or metal oxide material, and a mesh is provided on the anode to filter the sewage and allow the sewage to pass through. The diameter of the anode 6 is slightly larger than that of the screening cathode. There is a distance between the screening cathode 5 and the anode, and between the anode and the shell 7. A sewage filtering chamber is formed between the screening cathode 5 and the anode. A holding chamber for holding purified sewage is formed between the anode and the shell 7, and the holding chamber is connected to the water outlet 4.

[0053] In order for the sieving cathode to work properly, the filter fineness of the anode must be smaller than the particle size of the particle electrode particles.

[0054] The screening cathode 5 is a porous material, and the material of the porous material is Ti or Cu or stainless steel or metal oxide.

[0055] The core structure of this valve is the screening cathode and the particle electrode in the cathode chamber. The particle electrode is a reactive solid powder with a particle size range of 1-1000 um and its surface modified or modified derivatives. Due to the large specific surface area of ​​the particle electrode, the mass transfer efficiency of pollutants to its surface is high, which can greatly improve the reaction activity. The fine solid powder needs to be separated from the water phase after completing the water treatment. The screening cathode can not only contact with the particle electrode during the reaction to polarize it and then produce an electrochemical reaction, but also serve as a filter medium to separate water and the particle electrode.

[0056] The particle electrode particles can be metal and its oxide particles, polarizable non-metal particles, and products of the above materials that have been modified or modified. The dosage is calculated based on the effective volume of the cathode chamber and is 1-20 g / L.

[0057] When the particle electrode is separated into solid and liquid on the inner surface of the cathode chamber, it forms a stack on the surface of the screening cathode 5 to produce a filter cake; the filter cake is used to improve the interception efficiency of the screening cathode 5 for the particle electrode and the pollutant removal efficiency.

[0058] A stirring device 8 is provided inside the cathode chamber to ensure that the particle electrodes are in a flowing and mixing state in the cathode chamber, so as to improve the mass transfer efficiency of the pollutants.

[0059] Example 2

[0060] A sewage treatment method, which is based on the integrated flow cathode dehalogenation sewage treatment system of Example 1, comprises the following steps:

[0061] The sewage enters the cathode chamber of the screening cathode coupled flow electrode electrochemical reduction reactor 10 under the action of the lifting pump 13 .

[0062] The particle electrode is fully mixed with the sewage under the stirring action of the stirring device.

[0063] The particle electrodes in the cathode chamber are cathodically polarized under the action of the electric field to generate atomic hydrogen, which dehalogenates the halogenated organic pollutants in the sewage.

[0064] The wastewater after the reaction passes through the screening effect of the screening cathode, and the particle electrode is retained in the cathode chamber to continue the reaction; the wastewater after dehalogenation purification passes through the cathode under the filtering effect of the screening cathode to complete the solid-liquid separation.

[0065] The purified sewage is discharged from the cathode chamber and then discharged through the sewage discharge component.

[0066] Example 3

[0067] This embodiment is a practical application scenario of degrading trichloroacetic acid using an integrated flow cathode dehalogenation wastewater treatment system.

[0068] The device structure is as follows Figures 1 to 3 As shown, the particle electrode is activated carbon particles with Pd metal loaded on the surface, with a particle size of 6 μm and a dosage of 5 g / L. The screening cathode material is a porous titanium tube with a filtration accuracy of 1 μm. The cathode chamber volume is about 20 mL. The anode is a ruthenium-iridium-titanium mesh cylinder. The cathode potential is -1 V vs Ag / AgCl, the hydraulic retention time is 4 min, and it operates in a single-pass continuous flow mode with free water inlet and the outlet is pumped by a pump.

[0069] 30 min after the reaction started, the concentration in the reactor reached equilibrium and the removal rate of pollutants reached 100%. Figure 4 shown.

[0070] Example 4

[0071] This embodiment is a practical application scenario of degrading 2,4-dichlorophenol using an integrated flow cathode dehalogenation wastewater treatment system.

[0072] The device structure is as follows Figures 1 to 3As shown, the particle electrode is Ti4O7 particles with Pd metal loaded on the surface, with a particle size of 10 μm and a loading amount of 10 g / L. The screening cathode material is a porous titanium tube with a filtration accuracy of 2 μm. The cathode chamber volume is about 20 mL. The anode is a ruthenium-iridium-titanium mesh cylinder. The cathode potential is -1.2 V vs Ag / AgCl, the hydraulic retention time is 6 min, and it operates in a single-pass continuous flow mode.

[0073] 40 minutes after the reaction started, the concentration in the reactor basically reached equilibrium, and the removal rate of pollutants reached 96%. Figure 5 shown.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An integrated flow cathode dehalogenation wastewater treatment system, characterized in that: include: A screening cathode coupled flowing electrode electrochemical reduction reactor (10) comprises a screening cathode (5), an anode and a housing (7) which are sequentially sleeved from the inside to the outside; the interior of the screening cathode (5) is in a cavity shape and forms a cathode chamber; a plurality of movable particle electrodes are arranged in the cathode chamber, and the particle electrodes undergo cathode polarization under the action of an electric field to generate atomic hydrogen for dehalogenating halogenated organic pollutants in sewage; the screening cathode (5) is a porous material, and the screening cathode (5) screens the sewage after the reaction and intercepts the particle electrodes; A power supply assembly, electrically connected to the screening cathode (5) and the anode respectively; A sewage input component is connected to the cathode chamber and is used to input sewage into the cathode chamber; A sewage discharge component, used to discharge the sewage after the reaction; The shell is cylindrical and penetrates from top to bottom; the screening cathode-coupled flowing electrode electrochemical reduction reactor (10) further comprises an upper sealing flange sealed at the top end of the shell and a lower sealing flange sealed at the bottom end of the shell; The upper sealing flange is provided with a water inlet (3) and a water outlet (4) which are connected to the cathode chamber, and the water outlet (4) is connected to the sewage discharge component; The anode is made of a mesh-shaped metal or metal oxide material, and is provided with a mesh for filtering sewage and allowing sewage to pass through; a holding cavity for holding purified sewage is formed between the anode and the housing (7), and the holding cavity is connected to the water outlet (4); The porous material is made of Ti, Cu, stainless steel or metal oxide.

2. The integrated flow cathode dehalogenation wastewater treatment system according to claim 1 is characterized in that: The particle electrode is reactive solid powder with a particle size ranging from 1 to 1000 um and its surface-modified or modified derivatives.

3. The integrated flow cathode dehalogenation wastewater treatment system according to claim 1 is characterized in that: The dosage of the particle electrode is set according to the effective volume of the cathode chamber; the dosage of the particle electrode is 1-20 g / L.

4. The integrated flow cathode dehalogenation wastewater treatment system according to claim 1 is characterized in that: When the particle electrode performs solid-liquid separation on the inner surface of the cathode chamber, a stack is formed on the surface of the screening cathode (5) to produce a filter cake; the filter cake is used to improve the interception efficiency of the screening cathode (5) for the particle electrode and the pollutant removal efficiency.

5. The integrated flow cathode dehalogenation wastewater treatment system according to claim 1, characterized in that: Also include one or more of the following: The power supply component is a DC regulated power supply or a constant potential instrument; The sewage input assembly comprises a water storage tank (12), a sewage input pipeline (14) and a lift pump (13); one end of the sewage input pipeline (14) is connected to the water storage tank (12), the other end of the sewage input pipeline (14) is connected to the cathode chamber, and the lift pump (13) is arranged on the sewage input pipeline (14); The sewage discharge assembly comprises a sewage output pipeline (15); A stirring device (8) is provided inside the cathode chamber to ensure that the particle electrodes are in a flowing and mixing state in the cathode chamber, so as to improve the mass transfer efficiency of pollutants.

6. A method for treating sewage, characterized in that: The method is carried out based on the integrated flow cathode dehalogenation wastewater treatment system according to any one of claims 1 to 5, and comprises the following steps: Passing the sewage into the cathode chamber of the screening-type cathode-coupled flowing electrode electrochemical reduction reactor (10) through the sewage input assembly; The particle electrodes in the cathode chamber are cathodically polarized under the action of the electric field, generating atomic hydrogen, which dehalogenates the halogenated organic pollutants in the sewage. The wastewater after the reaction is screened by the screening cathode, and the particle electrode is retained in the cathode chamber to continue the reaction; The purified sewage is discharged from the cathode chamber and then discharged through the sewage discharge component.

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