Method and device for efficiently removing refractory organic pollutants or new pollutants in water

Abstract

The invention relates to a method for efficiently removing refractory organic pollutants or new pollutants in water, which comprises the following steps: at normal temperature and normal pressure, pretreating wastewater containing the refractory organic pollutants or new pollutants to remove suspended matters, and adding acid or alkali into an adjusting tank to adjust the pH value of the wastewater to 4-10; then conveying the wastewater into a continuous flow membrane chemical reactor through a lifting pump, and respectively adding an agent A and an agent B in the process of conveying the wastewater into the continuous flow membrane chemical reactor; the hydraulic retention time of the wastewater in the continuous flow membrane chemical reactor is 1-4H, and the agent A generates oxyradical under the action of the agent B and the continuous flow membrane chemical reactor; refractory organic pollutants or new pollutants in the wastewater are mineralized into carbon dioxide and water or biochemical micromolecular organic matters under the action of oxyradicals, the membrane assembly forms negative pressure under the action of the water producing pump, and the treated wastewater is discharged after being subjected to negative pressure filtration by the membrane assembly, so that the wastewater treatment is completed.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, in particular to a method and a device for efficiently removing refractory organic pollutants or new pollutants in water. Background Art

[0002] In recent years, with the acceleration of industrialization and changes in lifestyle, the amount of refractory organic pollutants and new pollutants in water bodies has increased, posing a serious threat to the ecological environment and human health. Traditional water treatment technologies, such as coagulation, sedimentation, and biological treatment, are often difficult to effectively remove these pollutants, especially new pollutants such as endocrine disruptors, microplastics, and drug residues. They are complex, hidden, and persistent, and pose long-term potential risks to the environment and human health. Therefore, it is urgent to develop an efficient, economical, and environmentally friendly water treatment technology to solve the current dilemma of water pollution control.

[0003] So far, the main methods for treating difficult-to-degrade organic pollutants / new pollutants are as follows: 1. Fenton method: Fenton method uses Fe 2+ The Fenton method catalyzes hydrogen peroxide (H2O2) to produce highly oxidizing hydroxyl radicals (·OH), which then oxidize and decompose organic matter. This method is most efficient when the pH is about 3 to 4. However, the Fenton method has several key disadvantages: it requires a large amount of acid and base to maintain the pH value required for the reaction, and Fe 2+ Large consumption of H2O2 will lead to the production of iron hydroxide sludge, and the high consumption of H2O2 increases the operating cost.

[0004] 2. Fenton-like methods: In order to solve the limitations of the Fenton method, Fenton-like methods have been developed, including electric Fenton, ultrasonic Fenton and ultraviolet light Fenton. These methods use external energy (such as electricity, sound waves, and light) to assist the activation of hydrogen peroxide, which can theoretically reduce the demand for H2O2. However, these improvements still fail to completely solve the problems of pH adjustment and sludge generation.

[0005] 3. Internal electrolysis method: The internal electrolysis method uses iron filings as filter material to treat wastewater through electrochemical reactions. This method also requires adjusting the pH value of the wastewater to the acidic range, and the dissolution of iron will produce additional iron ions, eventually forming iron hydroxide sludge.

[0006] 4. Activated persulfate method: The activated persulfate method is a technology that uses persulfate (usually peroxymonosulfate or peroxydisulfate) to generate highly active free radicals under the action of a catalyst, thereby oxidizing and degrading organic pollutants in water. Existing activation methods include: (1) Metal-based activated persulfate method: such as transition metal ions Fe 2+, Cu 2+ , Mn 2+ Or metal oxides such as MnO2, Fe2O3, etc., which can catalyze persulfate to produce sulfate radicals (·SO4 — ) and hydroxyl radicals (·OH). However, there are the following disadvantages: it may introduce secondary pollution, such as metal ion residues; the loss and regeneration of metal catalysts are difficult.

[0007] (2) Non-metallic catalyst activation of persulfate method: such as carbon-based material activation, carbon nanotubes (CNTs), graphene, activated carbon, etc., which activate persulfate through an electron transfer mechanism; such as MOFs (metal organic framework) activation, MOFs as a new catalyst, has a high specific surface area and controllability, and can efficiently activate persulfate. However, there are the following shortcomings: high material cost; the stability and recyclability of the catalyst still need to be improved; and secondary pollution may be introduced, such as residual carbon nanotubes.

[0008] (3) Photocatalytic activation of persulfate method: Use photocatalytic catalysts (such as TiO2, CdS, etc.) to activate persulfate under ultraviolet or visible light to generate free radicals. However, there are the following shortcomings: the photocatalytic efficiency is affected by light intensity and time; the quantum efficiency of the photocatalyst is low.

[0009] (4) Plasma-activated persulfate method: Plasma treatment can enhance the catalytic activity of materials such as carbon nanotubes and improve the activation efficiency of persulfate. However, there are the following shortcomings: relatively high equipment investment and maintenance costs; technical maturity and industrial application are still under development.

[0010] 5. Other methods: In addition to the above methods, there are also incineration, multiple-effect evaporation and sodium bismuthate oxidation methods. These methods are less common in actual engineering applications due to cost, safety or efficiency considerations. Summary of the invention

[0011] The technical problem to be solved by the present invention is: to solve the above technical problems existing in the prior art and to provide a method and device for efficiently removing refractory organic pollutants / new pollutants in water.

[0012] The technical solution to solve the above technical problems is: a method for efficiently removing refractory organic pollutants or new pollutants in water, comprising the following steps: at normal temperature and pressure, pre-treating wastewater containing refractory organic pollutants or new pollutants to remove suspended matter, adding acid or alkali in a regulating tank to adjust the pH value of the wastewater to 4-10; then sending the wastewater to a continuous flow membrane chemical reactor through a lift pump, and adding reagent A and reagent B respectively in the process of sending the wastewater to the continuous flow membrane chemical reactor; the hydraulic retention time of the wastewater in the continuous flow membrane chemical reactor is 1-4 hours, and the reagent A generates oxidative free radicals under the action of the reagent B and the continuous flow membrane chemical reactor; the refractory organic pollutants or new pollutants in the wastewater are mineralized into carbon dioxide and water, or small molecular organic matter that can be biodegraded under the action of the oxidative free radicals, and treated wastewater is obtained at this time; the membrane assembly in the continuous flow membrane chemical reactor forms a negative pressure under the action of a water production pump, and the treated wastewater is discharged after negative pressure filtration of the membrane assembly, and the wastewater treatment is completed.

[0013] A further technical solution of the present invention is: the dosage of agent A is 50-1000 mg / L▪wastewater, and the dosage of agent B is 100-500 mg / L▪wastewater; agent B is a non-consumable agent and can be replaced after the wastewater circulates in the continuous flow membrane chemical reactor with an effective circulation time of 12-48 hours.

[0014] Agent A is monopersulfate, and agent A is one or two of potassium monopersulfate and sodium monopersulfate.

[0015] Agent B includes the following components in mass proportions: 1 part of sodium nanobismuthate, 1.5-2 parts of anhydrous ethanol, 1 part of hydroxylated multi-walled carbon nanotubes, 1-2 parts of hydrochloric acid solution with a concentration of 65%-80%, 1 part of sodium acetate solution with a mass fraction of 10%-30%, 1 part of polyphenylene vinylene, and 1.5-2.5 parts of tetrahydrofuran in a mass ratio.

[0016] A further technical solution of the present invention is: the method for preparing agent B is: at normal temperature and pressure, Step A. Mixing nano sodium bismuthate and anhydrous ethanol in a mass ratio of 1:1.5-2 and dissolving by ultrasonication for 5-10 minutes to obtain a nano sodium bismuthate dispersion; Step B. mixing the hydroxylated multi-walled carbon nanotubes with a hydrochloric acid solution having a concentration of 65%-80% at a mass ratio of 1:1-2 and dissolving them by ultrasonication for 30-60 minutes, then filtering, washing with deionized water, and drying to obtain acidified hydroxylated multi-walled carbon nanotubes; Step C. mixing the acidified hydroxylated multi-walled carbon nanotubes obtained in step B with the nano sodium bismuthate dispersion obtained in step A at a mass ratio of 1:1-1.2 and dissolving them by ultrasonication for 60-120 minutes, then filtering, washing with deionized water and ethylene glycol twice or more, and drying to obtain sodium bismuthate-hydroxylated multi-walled carbon nanotubes; Step D. preparing a sodium acetate solution with a mass concentration of 10%-30% with deionized water, mixing the sodium bismuthate-hydroxylated multi-walled carbon nanotubes obtained in step C with the sodium acetate solution at a mass ratio of 1:1-1.5 and ultrasonically dispersing for 30-60 minutes to obtain sodium acetate-sodium bismuthate-hydroxylated multi-walled carbon nanotubes; Step E. Mixing polyphenylene vinylene and tetrahydrofuran in a mass ratio of 1:1.5-2.5 and ultrasonically dispersing for 60-120 minutes to obtain a polyphenylene vinylene-tetrahydrofuran solution; Step F. The polyphenylene vinylene-tetrahydrofuran solution obtained in step E is mixed with the sodium acetate-sodium bismuthate-hydroxylated multi-walled carbon nanotubes in step D at a mass ratio of 1.1-1.2:1 and ultrasonically dispersed for 30-60 minutes. After completion, the obtained solution is injected into a spray dryer at a drying temperature of 120-200° C. and a spray pressure of 30-40 MPa. After drying, a sodium bismuthate-hydroxylated multi-walled carbon nanotube granular material, i.e., agent B, is obtained.

[0017] A further technical solution of the present invention is: the continuous flow membrane chemical reactor includes a dosing system for agent A, a dosing system for agent B, a micro-nano bubble generator and a reaction tower, the reaction tower is provided with a sewage water distribution pipe, a micro-nano bubble release pipe, an electrode plate, a three-phase separator, a membrane assembly and a water outlet pipe from bottom to top, the sewage water distribution pipe is respectively connected to the dosing system A and the dosing system for agent B, and the micro-nano bubble release pipe is connected to the micro-nano bubble generator.

[0018] The positive and negative electrodes of the electrode plates are arranged alternately, the positive electrode is a graphite electrode, the cathode is a titanium plate electrode, the distance between the positive and negative electrodes is 5-15cm, the positive electrode is connected to the positive electrode of the DC charger, and the negative electrode is connected to the negative electrode of the low-voltage DC charger. The output voltage of the low-voltage DC charger is set to 5-25V.

[0019] The three-phase separator is composed of a plurality of triangular groove plates, the top angle of the triangular groove plates is 60-80°, the vertical height of the triangular groove plates is 20-30cm, and exhaust holes are opened in the gas collecting area at the top angle of the triangular groove plates. The three-phase separator is composed of triangular groove plates arranged, and the triangular groove plates are arranged and placed to form a layer of triangular groove plates. The three-phase separator is provided with multiple layers of triangular groove plates from bottom to top, and the upper and lower triangular groove plates are arranged and installed in a staggered manner, and the horizontal projection distance of the gap between the upper triangular groove plate and the lower triangular groove plate is 5-15cm.

[0020] The membrane assembly is composed of filamentous hollow fiber membranes, which are immersed at least 30 cm below the liquid level of the reaction tower, and the pore size of the filamentous fiber membranes is less than 0.1 μm.

[0021] Due to the adoption of the above technical solution, the method and device for efficiently removing refractory organic pollutants or new pollutants in water of the present invention have the following beneficial effects: 1. The present invention generates oxidative free radicals through the action of reagent A and reagent B and a continuous flow membrane chemical reactor; the refractory organic pollutants or new pollutants in the wastewater are mineralized into carbon dioxide and water, or small molecular organic matter that can be biodegraded under the action of oxidative free radicals. The method of the present invention is applicable to a wide pH range of wastewater, and has a good purification effect between pH values ​​of 4 and 10, solving the problem of requiring a large amount of acid and alkali to maintain the pH value required for the reaction and generating a large amount of sludge.

[0022] 2. The continuous flow membrane chemical reactor (CF-MCR) of the present invention introduces a three-phase separator and a filamentous hollow fiber membrane, and the residual coagulation and precipitation reduce the pollution output while saving land. The introduction of a three-phase separator in the continuous flow membrane chemical reactor (CF-MCR) reduces the filtration pressure of the filamentous hollow fiber membrane and prolongs its regeneration cycle and service life. The agent B of the present invention is granulated, which is convenient for precipitation and filtration, so as to facilitate recovery and recycling, thereby reducing operating costs and avoiding secondary pollution caused by residual carbon nanotubes.

[0023] 3. Compared with other existing processes, the present invention has the characteristics of simple operation, no secondary pollution, high economic benefits, etc., and the removal rate of difficult-to-degrade organic pollutants / new pollutants is as high as over 95%.

[0024] The technical features of a method and device for efficiently removing refractory organic pollutants or new pollutants in water according to the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : A process flow chart for efficiently removing difficult-to-degrade organic pollutants / new pollutants from water.

[0026] Figure 2 : Schematic diagram of the structure of a continuous flow membrane chemical reactor (CF-MCR) for efficiently removing difficult-to-degrade organic pollutants / new pollutants in water.

[0027] Figure 3 : Schematic diagram of the layout of sewage distribution pipes.

[0028] Figure 4 : Schematic diagram of the arrangement of micro-nano bubble release tubes.

[0029] Figure 5 : Schematic diagram of the electrode plate arrangement from top view.

[0030] Figure 6 : Schematic diagram of the structure of the electrode plate bracket.

[0031] Figure 7 : Schematic diagram of the three-phase separator structure.

[0032] Figure 8 : Schematic diagram of the three-phase separator from top view.

[0033] Fig. 9 : Top view of the three-phase separator bracket.

[0034] Fig.10 : Schematic diagram of the structure of the electrode plate bracket.

[0035] Fig.11 : Schematic diagram of the structure of the dosing system of agent A.

[0036] Fig.12 : Schematic diagram of the structure of the dosing system of agent B.

[0037] Fig.13 : Schematic diagram of the triangular groove plate structure of the three-phase separator.

[0038] Fig.14 : Phenol removal rate curve of Experiment 1.

[0039] Fig.15 : COD removal rate curve of Experiment 2.

[0040] In the above drawings, the descriptions of the reference numerals are as follows: 1-water inlet of sewage lifting pump, 2-sewage lifting pump, 3-water inlet flowmeter, 4-pipeline mixer A, 5-medicine A dosing system, 6-pipeline mixer B, 7-medicine B dosing system, 8-micro-nano bubble generator, 9-sewage water distribution pipe, 10-micro-nano bubble release tube, 11-electrode plate support bracket, 12-cathode, 13-anode, 14-ORP meter, 15-three-phase separator support bracket, 16-three-phase separator, 17-three-phase separator exhaust vertical Pipe, 18-liquid level controller, 19-membrane assembly, 20-pressure gauge, 21-water production pump, 22-water production flow meter, 23-low-voltage DC charger, 24-slag discharge port, 25-triangular groove plate of three-phase separator, 26-exhaust pipe, 27-continuous flow membrane chemical reactor (CF-MCR), 28-spiral releaser, 29-electrode plate slot, 30-solvent box A, 31-metering pump A, 32-solvent box B, 33-metering pump B, A-vertex angle of the triangular groove plate. DETAILED DESCRIPTION

[0041] A method for efficiently removing refractory organic pollutants or new pollutants from water, comprising the following steps: at normal temperature and pressure, pre-treating wastewater containing refractory organic pollutants or new pollutants to remove suspended solids, adding acid or alkali to a regulating tank to adjust the pH value of the wastewater to 4-10; then quantitatively sending the wastewater to a continuous flow membrane chemical reactor (Continuous Flow Membrane Chemical Reactor (abbreviated as CF-MCR), reagent A and reagent B are respectively added through a pipeline mixer during the process of transporting wastewater to the continuous flow membrane chemical reactor; the hydraulic retention time of wastewater in the continuous flow membrane chemical reactor is 1 to 4 hours, and reagent A produces oxidative free radicals under the action of reagent B and the continuous flow membrane chemical reactor; the refractory organic pollutants or new pollutants in the wastewater are mineralized into carbon dioxide and water, or small molecular organic matter that is more easily biodegradable under the action of oxidative free radicals, which is beneficial to subsequent biochemical treatment, and treated wastewater is obtained at this time; the membrane component in the continuous flow membrane chemical reactor forms negative pressure under the action of the water production pump, and the treated wastewater is discharged after being filtered by the negative pressure of the membrane component, and the wastewater treatment is completed at this time.

[0042] The dosage of agent A is 50-1000 mg / L of wastewater, and the dosage of agent B is 100-500 mg / L of wastewater. Agent B is a non-consumable agent and is replaced after the wastewater circulates in the continuous flow membrane chemical reactor for an effective circulation time of 12-48 hours. Agent A is monopersulfate, and agent A is one or two of potassium monopersulfate and sodium monopersulfate. Agent B includes the following components in mass ratio: 1 part of sodium nanobismuthate, 1.5-2 parts of anhydrous ethanol, 1 part of hydroxylated multi-walled carbon nanotubes, 1-2 parts of hydrochloric acid solution with a concentration of 65%-80%, 1 part of sodium acetate solution with a mass fraction of 10%-30%, 1 part of polyphenylene vinylene, and 1.5-2.5 parts of tetrahydrofuran by mass ratio. Agent B is a non-consumable agent and is replaced after the wastewater circulates in the continuous flow membrane chemical reactor for an effective circulation time of 12-48 hours. Agent B is a non-consumable agent. It is solid and suspended. Under the action of hydraulic pressure, some of it will be broken and pass through the membrane, thus causing losses. Therefore, it can be supplemented to maintain a certain concentration.

[0043] The preparation method of agent B is as follows: at normal temperature and pressure: Step A. Mixing nano sodium bismuthate and anhydrous ethanol in a mass ratio of 1:1.5-2 and dissolving by ultrasonication for 5-10 minutes to obtain a nano sodium bismuthate dispersion; Step B. mixing the hydroxylated multi-walled carbon nanotubes with a hydrochloric acid solution having a concentration of 65%-80% at a mass ratio of 1:1-2 and dissolving them by ultrasonication for 30-60 minutes, and then filtering, washing with deionized water and drying to obtain acidified hydroxylated multi-walled carbon nanotubes; Step C. mixing the acidified hydroxylated multi-walled carbon nanotubes obtained in step B with the nano sodium bismuthate dispersion obtained in step A at a mass ratio of 1:1-1.2 and dissolving them by ultrasonication for 60-120 minutes, then filtering, washing with deionized water and ethylene glycol twice or more, and drying to obtain sodium bismuthate-hydroxylated multi-walled carbon nanotubes; Step D. preparing a sodium acetate solution with a mass concentration of 10%-30% with deionized water, mixing the sodium bismuthate-hydroxylated multi-walled carbon nanotubes obtained in step C with the sodium acetate solution at a mass ratio of 1:1-1.5 and ultrasonically dispersing for 30-60 minutes to obtain sodium acetate-sodium bismuthate-hydroxylated multi-walled carbon nanotubes; Step E. Mixing polyphenylene vinylene and tetrahydrofuran in a mass ratio of 1:1.5-2.5 and ultrasonically dispersing for 60-120 minutes to obtain a polyphenylene vinylene-tetrahydrofuran solution; Step F. The polyphenylene vinylene-tetrahydrofuran solution obtained in step E is mixed with the sodium acetate-sodium bismuthate-hydroxylated multi-walled carbon nanotubes in step D at a mass ratio of 1.1-1.2:1 and ultrasonically dispersed for 30-60 minutes. After completion, the obtained solution is injected into a spray dryer at a drying temperature of 120-200° C. and a spray pressure of 30-40 MPa. After drying, a sodium bismuthate-hydroxylated multi-walled carbon nanotube granular material, i.e., agent B, is obtained.

[0044] Filtration, washing and drying in the preparation process are all routine operations.

[0045] The continuous flow membrane chemical reactor includes a dosing system for reagent A, a dosing system for reagent B, a micro-nano bubble generator and a reaction tower. The reaction tower is provided with a sewage water distribution pipe, a micro-nano bubble release pipe, an electrode plate, a three-phase separator, a membrane assembly and a water outlet pipe from bottom to top. The sewage water distribution pipe is connected to the dosing system A and the dosing system for reagent B respectively, and the micro-nano bubble release pipe is connected to the micro-nano bubble generator. The positive and negative electrodes of the electrode plates are arranged alternately, the positive electrode is a graphite electrode, the cathode is a titanium plate electrode, the spacing between the positive and negative electrodes is 5-15cm, the positive electrode is connected to the positive electrode of the DC charger 23, and the negative electrode is connected to the negative electrode of the low-voltage DC charger. The output voltage of the low-voltage DC charger 23 is set to 5-25V. The three-phase separator consists of two layers of triangular groove plates, each layer of which has a vertical height of 20-30 cm and a vertex angle of 60-80°. The two layers of triangular groove plates are installed at different heights, and the horizontal projection distance of the gap between the upper triangular groove plate and the lower triangular groove plate is 5-15 cm. The membrane assembly consists of filamentous hollow fiber membranes, which are immersed at least 30 cm below the liquid level of the reaction tower, and the pore size of the filamentous fiber membrane is less than 0.1 μm.

[0046] Specifically, it is an embodiment: A device for efficiently removing refractory organic pollutants or new pollutants in water is a continuous flow membrane chemical reactor, comprising a sewage lifting pump 2, a water inlet flowmeter 3, a pipeline mixer A4, a pipeline mixer B6, a reagent A dosing system 5, a reagent B dosing system 7, a micro-nano bubble generator 8, a reaction tower 27, an electrode plate, a three-phase separator 16, a liquid level controller 18, a membrane assembly 19, a water outlet pressure gauge 20, a water production pump 21, and a water production flowmeter 22. A sewage water distribution pipe 9 is distributed at the lower end of the reaction tower 27, and the sewage water distribution pipe 9 is connected to the sewage lifting pump water inlet 1 through the sewage lifting pump 2, and the water inlet flowmeter 3 is arranged at the connection between the sewage water distribution pipe 9 and the sewage lifting pump 2. The reagent A dosing system 5 and the reagent B dosing system 7 are distributed and connected to the sewage water distribution pipe 9 through the pipeline mixer A4 and the pipeline mixer B6. The reaction tower 27 is provided with a micro-nano bubble release tube 10, which is located above the sewage distribution pipe 9 and is connected to the micro-nano bubble generator 8. A spiral releaser 28 is connected to the micro-nano bubble release tube 10, and each spiral releaser 28 has a service area of ​​0.1-0.2m 2 .

[0047] The electrode plate is arranged in the reaction tower 27 through the electrode plate supporting bracket. The electrode plates are respectively arranged 10-20 cm above the micro-nano bubble release tube 10. The negative electrode 12 and the positive electrode 13 of the electrode plate are respectively connected to the low-voltage DC charger 23; the positive electrode 13 and the negative electrode 12 of the electrode plate are arranged in an alternating manner. The positive electrode 13 is a graphite electrode, and the cathode 12 is a titanium plate electrode. The distance between the positive electrode 13 and the negative electrode 12 is 5-15 cm. The positive electrode 13 is connected to the positive electrode connected to the low-voltage DC charger 23, and the negative electrode 12 is connected to the negative electrode connected to the low-voltage DC charger 23. The output voltage of the low-voltage DC charger 23 is set to 5-25V. The electrode plate supporting bracket installed on the electrode plate is the same bracket at the top and bottom. The electrode plate supporting bracket is provided with an electrode plate slot for placing the electrode plate. The lower bracket is used for shaping and bearing, and the upper bracket is only used for shaping.

[0048] The three-phase separator 16 is arranged in the reaction tower 27 through the three-phase separator support bracket 15, and the three-phase separator 16 is arranged 30-50cm above the electrode plate; the three-phase separator 16 is composed of a plurality of triangular groove plates 25, the triangular groove plate is a triangular structure formed by connecting two plates, the vertex angle A of the triangular groove plate 25 is 60-80°, the vertical height of the triangular groove plate 25 is 20-30cm, and the gas collecting area at the vertex of the triangular groove plate 25 is provided with an exhaust hole, and an exhaust pipe is provided at the exhaust hole. The triangular groove plates 25 are arranged and placed to form a layer of triangular groove plates, and the three-phase separator 16 is provided with multiple layers of triangular groove plates from bottom to top. The upper and lower triangular groove plates are arranged and installed in a staggered manner, and the horizontal projection distance of the gap between the upper triangular groove plate and the lower triangular groove plate is 5-15cm. Each layer of triangular groove plates is directly connected by a connecting rod. The exhaust pipes 26 at the vertex angles of the triangular groove plates of each layer are connected in series and discharged from the liquid surface through the exhaust vertical pipe 17. In this embodiment, the three-phase separator is composed of two layers of triangular groove plates, which are installed in a staggered manner, and the horizontal projection distance of the gap between the upper triangular groove plate and the lower triangular groove plate is 5-15 cm.

[0049] The working principle of the three-phase separator 16: the wastewater entering the reaction tower 27 is decomposed to produce carbon dioxide, sewage, and the granular agent B attached with gas and the gas released by the micro-nano bubble generator enter the three-phase separator 16, and the gas enters the gas collection area at the top corner of the triangular groove plate 25. In the process of collision with the three-phase separator 16 and mutual collision, the granular agent B attached with gas is separated from the granular agent B. After separation, the gas enters the gas collection area at the top corner of the triangular groove plate 25, and the granular agent B settles back to the reaction area of ​​the negative electrode 12 and the positive electrode 13 of the electrode plate. The exhaust holes of the gas collection area at the top corners of each triangular groove plate 25 are connected in series to discharge the gas from the liquid surface through the exhaust vertical pipe 17 set on the three-phase separator.

[0050] The membrane assembly 19 is arranged in the reaction tower 27 and is located 30-50 cm above the three-phase separator 16. The membrane assembly 19 is connected to the water production flow meter 22 and the water production pump 21 through the drainage pipe. The membrane assembly 19 is composed of a filamentary hollow fiber membrane. The membrane assembly 19 is immersed at least 30 cm below the liquid level of the reaction tower. The pore size of the filamentary hollow fiber membrane is less than 0.1 μm. A water production pressure gauge 20 is provided on the drainage pipe between the membrane assembly 19 and the water production pump 21.

[0051] The liquid level controller 18 is arranged in the reaction tower 27 and is located above the three-phase separator 16. The liquid level controller 18 is interlocked with the sewage lifting pump 2. When the liquid level controller 18 is at a low liquid level, the sewage lifting pump 2 starts, and when the liquid level controller 18 is at a high liquid level, the sewage lifting pump 2 stops. The reagent A dosing system 5 includes a dissolving tank A, a metering pump A and an ORP meter. The ORP meter is arranged above the electrode plate in the reaction tower. The metering pump is interlocked with the ORP meter 14 on the upper electrode plate in the reaction tower. When the ORP is less than 500mV, the metering pump A starts; when the ORP is greater than 800mV, the metering pump A stops. The reagent B dosing system 7 includes a dissolving tank B, a metering pump B and a time relay. The metering pump B is interlocked with the time relay to realize automatic start and stop.

[0052] The electrode plate support bracket 11 and the three-phase separator support bracket 15 are respectively mesh structures with intervals. The membrane assembly 19, the pipeline mixer and the spiral releaser 28 can be existing devices.

[0053] Experimental results: Experiment 1: Phenol was treated by using the method and device for efficiently removing refractory organic pollutants / new pollutants in water according to the present invention. The mass concentration of phenol was 10 mg / L. Process conditions: normal temperature and pressure, pH=7, the dosage of reagent A was 100 mg / L, and the dosage of reagent B was 100 mg / L. The phenol removal rate was as follows: Fig.14 shown.

[0054] Experiment 2: The method and device for efficiently removing refractory organic pollutants / new pollutants in water described in the present invention were used to treat the production wastewater of a high-end pharmaceutical raw material and pharmaceutical preparation project, with a COD mass concentration of 12000 mg / L. Process conditions: normal temperature and pressure, pH=7, the dosage of reagent A is 500 mg / L▪wastewater, and the dosage of reagent B is 300 mg / L▪wastewater. COD removal rate is as follows Fig.15 shown.

Claims

1. A method for efficiently removing refractory organic pollutants or new pollutants in water, characterized in that: The following steps are involved: At normal temperature and pressure, wastewater containing refractory organic pollutants or new pollutants is pretreated to remove suspended solids, and acid or alkali is added to the regulating tank to adjust the pH value of the wastewater to 4-10; then the wastewater is sent to the continuous flow membrane chemical reactor through a lifting pump, and reagent A and reagent B are added respectively in the process of sending the wastewater to the continuous flow membrane chemical reactor; the hydraulic retention time of the wastewater in the continuous flow membrane chemical reactor is 1-4 hours, and reagent A produces oxidative free radicals under the action of reagent B and the continuous flow membrane chemical reactor; the refractory organic pollutants or new pollutants in the wastewater are mineralized into carbon dioxide and water, or small molecular organic matter that can be biodegraded under the action of oxidative free radicals, and treated wastewater is obtained at this time; the membrane assembly in the continuous flow membrane chemical reactor forms negative pressure under the action of the water production pump, and the treated wastewater is discharged after negative pressure filtration of the membrane assembly, and the wastewater treatment is completed.

2. A method for efficiently removing refractory organic pollutants or new pollutants in water according to claim 1, characterized in that: The dosage of agent A is 50-1000 mg / L wastewater, and the dosage of agent B is 100-500 mg / L wastewater.

3. The method for efficiently removing refractory organic pollutants or new pollutants in water according to claim 1, characterized in that: Agent A is monopersulfate, and agent A is one or two of potassium monopersulfate and sodium monopersulfate.

4. The method for efficiently removing refractory organic pollutants or new pollutants in water according to claim 1, characterized in that: Agent B includes the following components in mass proportions: 1 part of sodium nanobismuthate, 1.5-2 parts of anhydrous ethanol, 1 part of hydroxylated multi-walled carbon nanotubes, 1-2 parts of hydrochloric acid solution with a concentration of 65%-80%, 1 part of sodium acetate solution with a mass fraction of 10%-30%, 1 part of polyphenylene vinylene, and 1.5-2.5 parts of tetrahydrofuran in a mass ratio.

5. The method for efficiently removing refractory organic pollutants or new pollutants in water according to claim 1, characterized in that: The preparation method of agent B is as follows: at normal temperature and pressure, Step A. Mixing nano sodium bismuthate and anhydrous ethanol in a mass ratio of 1:1.5-2 and dissolving by ultrasonication for 5-10 minutes to obtain a nano sodium bismuthate dispersion; Step B. mixing the hydroxylated multi-walled carbon nanotubes with a hydrochloric acid solution having a concentration of 65%-80% at a mass ratio of 1:1-2 and dissolving them by ultrasonication for 30-60 minutes, then filtering, washing with deionized water, and drying to obtain acidified hydroxylated multi-walled carbon nanotubes; Step C. mixing the acidified hydroxylated multi-walled carbon nanotubes obtained in step B with the nano sodium bismuthate dispersion obtained in step A at a mass ratio of 1:1-1.2 and dissolving them by ultrasonication for 60-120 minutes, then filtering, washing with deionized water and ethylene glycol twice or more, and drying to obtain sodium bismuthate-hydroxylated multi-walled carbon nanotubes; Step D. preparing a sodium acetate solution with a mass concentration of 10%-30% with deionized water, mixing the sodium bismuthate-hydroxylated multi-walled carbon nanotubes obtained in step C with the sodium acetate solution at a mass ratio of 1:1-1.5 and ultrasonically dispersing for 30-60 minutes to obtain sodium acetate-sodium bismuthate-hydroxylated multi-walled carbon nanotubes; Step E. Mixing polyphenylene vinylene and tetrahydrofuran in a mass ratio of 1:1.5-2.5 and ultrasonically dispersing for 60-120 minutes to obtain a polyphenylene vinylene-tetrahydrofuran solution; Step F. The polyphenylene vinylene-tetrahydrofuran solution obtained in step E is mixed with the sodium acetate-sodium bismuthate-hydroxylated multi-walled carbon nanotubes in step D at a mass ratio of 1.1-1.2:1 and ultrasonically dispersed for 30-60 minutes. After completion, the obtained solution is injected into a spray dryer at a drying temperature of 120-200° C. and a spray pressure of 30-40 MPa. After drying, a sodium bismuthate-hydroxylated multi-walled carbon nanotube granular material, i.e., agent B, is obtained.

6. The method for efficiently removing refractory organic pollutants or new pollutants in water according to claim 1, characterized in that: The continuous flow membrane chemical reactor comprises a dosing system for reagent A, a dosing system for reagent B, a micro-nano bubble generator and a reaction tower. The reaction tower is provided with a sewage water distribution pipe, a micro-nano bubble release pipe, an electrode plate, a three-phase separator, a membrane assembly and a water outlet pipe from bottom to top. The sewage water distribution pipe is respectively connected to the dosing system A and the dosing system for reagent B, and the micro-nano bubble release pipe is connected to the micro-nano bubble generator.

7. A method for efficiently removing refractory organic pollutants or new pollutants in water according to claim 6, characterized in that: The positive and negative electrodes of the electrode plates are arranged alternately, the positive electrode is a graphite electrode, the cathode is a titanium plate electrode, the distance between the positive and negative electrodes is 5-15cm, the positive electrode is connected to the positive electrode of the DC charger, and the negative electrode is connected to the negative electrode of the low-voltage DC charger. The output voltage of the low-voltage DC charger is set to 5-25V.

8. The method for efficiently removing refractory organic pollutants or new pollutants in water according to claim 6, characterized in that: The three-phase separator is composed of a plurality of triangular groove plates, the top angle of the triangular groove plates is 60-80 degrees, the vertical height of the triangular groove plates is 20-30 cm, and exhaust holes are provided in the gas collecting areas at the top angles of the triangular groove plates.

9. A method for efficiently removing refractory organic pollutants or new pollutants in water according to claim 8, characterized in that: The three-phase separator is composed of triangular groove plates arranged, and the triangular groove plates are arranged to form a layer of triangular groove plates. The three-phase separator is provided with multiple layers of triangular groove plates from bottom to top, and the upper and lower triangular groove plates are arranged and installed in a staggered manner. The horizontal projection distance of the gap between the upper triangular groove plate and the lower triangular groove plate is 5-15cm.

10. The method for efficiently removing refractory organic pollutants or new pollutants in water according to claim 6, characterized in that: The membrane assembly is composed of filamentous hollow fiber membranes, which are immersed at least 30 cm below the liquid level of the reaction tower, and the pore size of the filamentous fiber membranes is less than 0.1 μm.

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