A heterogeneous Fenton reactor, an apparatus and method for treating organic wastewater

Abstract

A heterogeneous Fenton-like reactor, an apparatus for treating organic wastewater, and a method thereof belong to the field of wastewater treatment technology. This invention overcomes the shortcomings of existing Fenton-like reactors, such as large footprint, high construction cost, long reaction time, and low mass transfer efficiency. The heterogeneous Fenton-like reactor of this invention includes a first influent system, a first static mixing catalytic oxidation pipeline, and a first static mixing element. One end of the first static mixing catalytic oxidation pipeline is connected to the first influent system, and the other end is provided with an outlet. The first static mixing element is disposed within the first static mixing catalytic oxidation pipeline. The first static mixing element has Fenton-like catalytic activity. The length-to-inner diameter ratio of the first static mixing catalytic oxidation pipeline is 20:1 to 200:1. This invention saves space, has a short reaction time, and high mass transfer efficiency.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a heterogeneous Fenton reactor, an apparatus and method for treating organic wastewater. Background Technology

[0002] Industrial production processes generate large quantities of recalcitrant organic wastewater, which is diverse and complex in composition, often containing various recalcitrant organic pollutants such as antibiotics, phenols, anilines, nitrobenzenes, phthalic acid, and chlorophenols, and possesses a certain degree of toxicity. This type of recalcitrant organic wastewater is typically difficult to treat stably to meet discharge standards using conventional methods such as flocculation sedimentation and biological treatment. Advanced oxidation can be used as a pretreatment or advanced treatment technology to remove recalcitrant organic pollutants.

[0003] Fenton technology, as one of the advanced oxidation technologies, utilizes Fe... 2+ The reactive oxygen species generated by hydrogen peroxide under acidic conditions can mineralize organic pollutants or decompose them into small molecules, and have been widely used in the treatment of recalcitrant organic wastewater. However, the traditional Fenton process still has the following shortcomings: (1) it has strict requirements on the pH of the wastewater (pH=2-4), the utilization efficiency of the oxidant is low, and the cost of the reagent is high; (2) a large amount of iron sludge is generated during the reaction process, and the by-products are difficult to treat; (3) incomplete mineralization is prone to generating residual pollutants, and the removal effect on some organic matter is not as expected.

[0004] Fenton-like processes can improve upon the shortcomings of traditional Fenton processes to some extent, reducing reagent consumption and iron sludge production, and improving catalytic efficiency. However, common Fenton-like reactors are mostly tower-type or tank-type fixed-bed reactors or fluidized-bed reactors, which occupy a large area, have high construction costs, long reaction times, and low mass transfer efficiency. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of existing Fenton-like reactors, such as large footprint, high construction cost, long reaction time and low mass transfer efficiency, so as to provide a heterogeneous Fenton-like reactor, an organic wastewater treatment device and method.

[0006] To this end, the present invention provides the following technical solution.

[0007] In a first aspect, the present invention provides a heterogeneous Fenton reactor, comprising a first inlet water system, a first static mixing catalytic oxidation pipeline, and a first static mixing element;

[0008] One end of the first static mixing catalytic oxidation pipeline is connected to the first water inlet system, and the other end is provided with a water outlet;

[0009] The first static mixing element is disposed inside the first static mixing catalytic oxidation pipeline;

[0010] The first static mixing element has Fenton-like catalytic reaction activity;

[0011] The ratio of the length to the inner diameter of the first static mixed catalytic oxidation pipe is 20:1 to 200:1.

[0012] Furthermore, the inner diameter of the first static mixed catalytic oxidation pipe is 0.1m to 1.0m.

[0013] Furthermore, the inner diameter of the first static mixing element is equivalent to that of the first static mixing catalytic oxidation pipe.

[0014] Furthermore, multiple first static mixed catalytic oxidation pipelines are arranged in parallel; to improve processing capacity, at least two first static mixed catalytic oxidation pipelines are arranged in parallel.

[0015] The first static mixed catalytic oxidation pipeline is relatively long and difficult to manufacture. Furthermore, the first static mixed catalytic oxidation pipeline is composed of two or more first pipeline units connected together, and the first pipeline units are connected to each other by a first flange.

[0016] Furthermore, the length of the first pipe unit is 1 to 15 meters.

[0017] Furthermore, it also includes the first dosing system;

[0018] The first dosing system includes an acidified FeSO4 solution dosing port, a hydrogen peroxide dosing port, a first dosing metering pump, and a first online pH meter; the first online pH meter is interlocked with the acid dosing pump used to prepare the acidified FeSO4 solution, so as to accurately control the reaction pH and the amount of dosing.

[0019] The acidified FeSO4 solution inlet and the hydrogen peroxide inlet are located between the first water inlet system and the first static mixing element.

[0020] Furthermore, the first water inlet system includes a first water inlet pump, a first water inlet pipe, and a first water distributor; the first water inlet pump and the first water distributor are connected through the first water inlet pipe, and the outlet of the first water distributor is connected to each of the first static mixing catalytic oxidation pipelines.

[0021] The acidified FeSO4 solution inlet and the hydrogen peroxide inlet are located on the first static mixing catalytic oxidation pipeline, after the first water distributor and before the inlet of the first static mixing element.

[0022] Furthermore, the first static mixing element is made of one or more of iron, manganese, copper, nickel, or their metal oxides.

[0023] Furthermore, the first static hybrid element is manufactured using methods such as 3D printing and chemical etching.

[0024] Furthermore, the first static mixing element is an SL-type static mixing element, an SX-type static mixing element, or an SK-type static mixing element; preferably, it is an SK-type static mixing element, suitable for wastewater with many impurities and less prone to clogging. Left-handed and right-handed spiral vanes are alternately connected to promote continuous fluid division and thorough mixing.

[0025] Furthermore, the first static mixing element is detachably disposed within the first static mixing catalytic oxidation pipeline; this facilitates replacement when the catalytic activity decreases, and the disassembled first static mixing element can be regenerated and reused in situ by acid washing and reshaping.

[0026] Furthermore, there are two or more first static mixing elements, which are discontinuously arranged within the first static mixing catalytic oxidation pipeline.

[0027] Furthermore, the operating pressure of the heterogeneous Fenton reactor is 10 kg / cm². 2 ~50kg / cm 2 .

[0028] Furthermore, an ultrasonic cleaning system is included, comprising an ultrasonic generator, an ultrasonic transducer, and a sound field interaction tank. The ultrasonic generator emits a high-frequency alternating current signal, driving the ultrasonic transducer to generate high-frequency mechanical vibration. This high-frequency mechanical vibration propagates through the sound field interaction tank and the first static mixing catalytic oxidation pipeline into the fluid within the pipeline. The ultrasonic frequency and duration are adjustable. Under the action of ultrasound, the iron sludge produced by the reaction of FeSO4 and hydrogen peroxide is transferred to the liquid phase and flows out of the heterogeneous Fenton-like reactor, effectively mitigating the caking phenomenon of the first static mixing element with Fenton-like catalytic activity. Simultaneously, ultrasound enhances the generation process of active oxygen species, promoting sufficient contact between pollutants in the wastewater and active oxygen species, thereby enhancing the catalytic reaction efficiency.

[0029] Furthermore, the ultrasonic cleaning system also includes an ultrasonic transducer slide, along which the ultrasonic transducer can move; and / or

[0030] The ultrasonic cleaning system is equipped with a sound insulation panel.

[0031] And / or, the ultrasonic transducer is designed with a noise reduction structure. This improves the noise reduction effect of the ultrasonic cleaning system. Specifically, the noise reduction structure is a buffer pad placed under the ultrasonic transducer.

[0032] The ultrasonic cleaning system also includes a PLC automatic control module, which controls the ultrasonic transducer to move automatically along the ultrasonic transducer slide. This allows for ultrasonic cleaning of the first static mixing catalytic oxidation pipeline at different locations, improving the flexibility of the ultrasonic cleaning system and reducing operating costs.

[0033] Furthermore, the first static mixing catalytic oxidation pipeline is made of 316L stainless steel.

[0034] The heterogeneous Fenton reactor of this invention can be applied to the pretreatment unit before the biochemical treatment of recalcitrant organic wastewater, and also to the advanced treatment unit after the biochemical treatment of recalcitrant organic wastewater.

[0035] Secondly, the present invention also provides a treatment device for recalcitrant organic wastewater, including the above-mentioned heterogeneous Fenton reactor and a heterogeneous direct oxidation transfer reactor, wherein the heterogeneous Fenton reactor and the heterogeneous direct oxidation transfer reactor are connected in series.

[0036] Furthermore, the outlet of the heterogeneous Fenton reactor is connected to the inlet of the heterogeneous direct oxidation transfer reactor.

[0037] Furthermore, it also includes a nanocatalyst cleaning and recovery system connected to the heterogeneous direct oxidation transfer reactor;

[0038] The nanocatalyst cleaning and recovery system includes a hydrocyclone separator, a catalyst return pipe, a catalyst cleaning chamber, and a time control valve.

[0039] The outlet of the heterogeneous direct oxidation transfer reactor is connected to the cyclone separator. The separated nanocatalyst enters the catalyst return pipe. The time control valve set on the catalyst return pipe controls the separated nanocatalyst to enter the catalyst cleaning chamber for cleaning and regeneration or to be directly returned to the heterogeneous direct oxidation transfer reactor.

[0040] The surface-saturated nanocatalyst enters the catalyst cleaning chamber, where it is regenerated through solvent elution. Once the catalyst surface is saturated, it can be cleaned and regenerated for reuse. The cleaned nanocatalyst, now in an unsaturated state, can be refluxed to the heterogeneous direct oxidation transfer reactor for continued use.

[0041] Preferably, the catalyst cleaning frequency is set to 4h / time to 6h / time.

[0042] Furthermore, the heterogeneous direct oxidation transfer reactor includes a second inlet water system, a second static mixing catalytic oxidation pipeline, and a second static mixing element;

[0043] One end of the second static mixing catalytic oxidation pipeline is connected to the second water inlet system, and the other end is provided with a water outlet;

[0044] The second static mixing element is disposed inside the second static mixing catalytic oxidation pipeline;

[0045] The ratio of the length to the inner diameter of the second static mixed catalytic oxidation pipe is 20:1 to 200:1.

[0046] Furthermore, the inner diameter of the second static mixed catalytic oxidation pipe is 0.1m to 1.0m.

[0047] Furthermore, the second static mixing element has a diameter equivalent to that of the second static mixing catalytic oxidation conduit.

[0048] Furthermore, there are two or more second static mixing elements, which are discontinuously arranged within the second static mixing catalytic oxidation pipeline.

[0049] Furthermore, the heterogeneous direct oxidation transfer reactor satisfies at least one of the following conditions:

[0050] (1) Multiple second static mixed catalytic oxidation pipelines are arranged in parallel;

[0051] The second static mixed catalytic oxidation pipeline is relatively long and difficult to prepare. Furthermore, the second static mixed catalytic oxidation pipeline is composed of two or more second pipeline units connected together, and the second pipeline units are connected to each other by a first flange.

[0052] Furthermore, the length of the second pipe unit is 1 to 15 meters.

[0053] (2) It also includes a second dosing system;

[0054] The second dosing system includes a nanocatalyst dosing port, a persulfate solution dosing port, a second dosing metering pump, and a second online pH meter;

[0055] The nanocatalyst inlet and the persulfate solution inlet are located between the second water inlet system and the second static mixing element.

[0056] (3) The second water inlet system includes a second water inlet pump, a second water inlet pipe and a second water distributor; the second water inlet pump and the second water distributor are connected through the second water inlet pipe, and the outlet of the second water distributor is connected to each of the second static mixing catalytic oxidation pipelines.

[0057] Furthermore, the nanocatalyst inlet and the persulfate solution inlet are located at the beginning section of the second static mixing catalytic oxidation pipeline after the second water distributor.

[0058] (4) The second static mixing element is made of polytetrafluoroethylene; the second static mixing element does not adsorb the nanocatalyst, but promotes the full mixing of pollutants, persulfate solution and nanocatalyst. The pollutants and persulfate undergo a direct oxidation transfer process on the surface of the nanocatalyst, the reduction potential of the pollutants is reduced and they are activated, the generated oxidation intermediates are stable on the surface of the nanocatalyst, and accumulate on the surface of the nanocatalyst through coupling or polymerization reaction, thereby achieving the removal of pollutants from wastewater.

[0059] (5) The second static mixing element is an SL-type static mixing element, an SX-type static mixing element, or an SK-type static mixing element;

[0060] (6) The second static mixing element is detachably disposed in the second static mixing catalytic oxidation pipeline.

[0061] Furthermore, the operating pressure of the heterogeneous direct oxidation transfer reactor is 10 kg / cm². 2 ~50kg / cm 2 .

[0062] Furthermore, the second static mixing catalytic oxidation pipeline is made of 316L stainless steel.

[0063] Furthermore, the nanocatalyst includes metal oxides, carbon materials, etc., and the persulfate is PMS. Preferably, the nanocatalyst is at least one of iron-manganese composite oxide, biochar, and carbon nanotubes.

[0064] The heterogeneous direct oxidation transfer reactor can be applied to the advanced treatment unit after the biochemical treatment of recalcitrant organic wastewater.

[0065] Thirdly, the present invention also provides a method for treating recalcitrant organic wastewater, comprising the following steps: subjecting the recalcitrant organic wastewater to a heterogeneous Fenton-like reaction first, and then subjecting it to a heterogeneous direct oxidation-transfer reaction.

[0066] Recalcitrant organic wastewater is pumped into a heterogeneous Fenton-like reactor via a first influent pump. FeSO4 reacts with the catalytically active element to catalyze hydrogen peroxide, generating reactive oxygen species that partially mineralize the high-concentration organic pollutants. During this advanced oxidation process, the hydrogen peroxide dosage is carefully controlled to reduce the organic pollutant concentration to an appropriate level. The effluent from the heterogeneous Fenton-like reactor, containing a lower concentration of organic pollutants, is pumped into a heterogeneous direct oxidation transfer reactor. With a lower persulfate dosage, the remaining organic pollutants undergo a direct oxidation transfer process with persulfate on the surface of the nanocatalyst, achieving a non-decompositional oxidation transfer of pollutants from the wastewater to the nanocatalyst surface.

[0067] Furthermore, in the heterogeneous Fenton reaction process, the pH of the recalcitrant organic wastewater is controlled at 5.0-5.5 using acidified FeSO4 solution and hydrogen peroxide, which can significantly reduce the dosage of acid and alkali reagents; the heterogeneous Fenton reaction time (i.e., the residence time of the recalcitrant organic wastewater in the heterogeneous Fenton reactor from entry to effluent) is 1-15 min.

[0068] Furthermore, in the heterogeneous direct oxidation transfer reaction process, the heterogeneous direct oxidation transfer reaction time is 1 to 15 minutes.

[0069] Furthermore, the treatment method for the recalcitrant organic wastewater employs the aforementioned heterogeneous Fenton reactor and heterogeneous direct oxidation transfer reactor, comprising:

[0070] S1. The first inlet pump pumps the recalcitrant organic wastewater into the first static mixing catalytic oxidation pipeline through the first inlet pipe;

[0071] S2. Add acidified FeSO4 solution at a concentration of 100 mg / L to 250 mg / L; add hydrogen peroxide at a concentration of 100 mg / L to 200 mg / L; the acidified FeSO4 solution is a FeSO4 solution pre-acidified with sulfuric acid; reaction time is 1 to 15 min.

[0072] S3, the second water inlet pump pumps the water effluent from S2 into the second static mixing catalytic oxidation pipeline through the second water inlet pipe;

[0073] S4. Add 0.5 g / L to 2.0 g / L of nano-catalyst and 25 mg / L to 50 mg / L of persulfate. After reacting for 1 to 15 minutes, effluent is discharged.

[0074] The technical solution of this invention has the following advantages:

[0075] 1. The heterogeneous Fenton-like reactor provided by the present invention includes a first inlet water system, a first static mixing catalytic oxidation pipeline, and a first static mixing element; one end of the first static mixing catalytic oxidation pipeline is connected to the first inlet water system, and the other end is provided with an outlet; the first static mixing element is disposed inside the first static mixing catalytic oxidation pipeline; the first static mixing element has Fenton-like catalytic reaction activity; the ratio of the length to the inner diameter of the first static mixing catalytic oxidation pipeline is 20:1 to 200:1.

[0076] The invention employs a slender first static mixing catalytic oxidation pipe, and inside it is set a first static mixing element with Fenton-like catalytic reaction activity. On the one hand, it saves space, investment and operating costs; on the other hand, the first static mixing element has abundant catalytic active sites, and has both efficient mixing and catalytic functions, which can shorten the reaction time and reduce the subsequent iron sludge production. It achieves high mass transfer efficiency and high catalytic efficiency with low energy consumption and short time. Moreover, the heterogeneous Fenton-like reactor of the present invention does not have the problem of uneven fluidization water distribution.

[0077] 2. The heterogeneous Fenton-like reactor provided by the present invention further includes an ultrasonic cleaning system, which comprises an ultrasonic generator, an ultrasonic transducer, and an acoustic field interaction tank. The first static mixing element can be cleaned and regenerated in situ using the ultrasonic cleaning system. The ultrasonic waves not only prevent the catalytically active first static mixing element from becoming caked and passivated, but also enhance the Fenton-like reaction process and improve catalytic efficiency.

[0078] 3. The heterogeneous Fenton reactor provided by this invention allows the ultrasonic transducer to move horizontally along the ultrasonic transducer chute under the control of a PLC automatic control module, thereby expanding the range of ultrasonic cleaning and improving the automation level and flexibility of the ultrasonic cleaning system.

[0079] 4. The method for treating recalcitrant organic wastewater provided by the present invention includes the following steps: subjecting the recalcitrant organic wastewater to a heterogeneous Fenton-like reaction first, and then subjecting it to a heterogeneous direct oxidation-transfer reaction.

[0080] This invention effectively couples advanced oxidation technology and direct oxidation transfer technology, ensuring stable effluent quality compliance within a reasonable reagent cost range. The heterogeneous Fenton-like reaction reduces organic pollutant levels from high to low concentrations. The heterogeneous direct oxidation transfer reaction initiates the non-decompositional oxidative transfer of remaining organic pollutants from wastewater to the surface of the nanocatalyst, exhibiting particularly good removal efficiency for organics containing electron-donating groups. This significantly reduces the amount of oxidant required during the heterogeneous direct oxidation transfer reaction, thus lowering costs.

[0081] The heterogeneous direct oxidation transfer reaction balances the amount of hydrogen peroxide added during the heterogeneous Fenton-like reaction and consumes the residual hydrogen peroxide in the effluent from the heterogeneous Fenton-like reaction, thus reducing reagent waste. Attached Figure Description

[0082] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0083] Figure 1 This is a schematic diagram of the heterogeneous Fenton reactor of Example 1;

[0084] Figure 2 This is a schematic diagram of the first static mixing element of the heterogeneous Fenton reactor in Example 1;

[0085] Figure 3 This is a schematic diagram of the ultrasonic cleaning system for the heterogeneous Fenton reactor in Example 1;

[0086] Figure 4 This is a schematic diagram of the treatment device for recalcitrant organic wastewater in Example 4;

[0087] Figure 5 This is a schematic diagram of the heterogeneous direct oxidation transfer reactor in Example 4.

[0088] Figure label:

[0089] 1-First inlet pipe, 2-First inlet pump, 3-First water distributor, 4-Acidified FeSO4 solution inlet, 5-Hydrogen peroxide inlet, 6-First static mixing element, 7-First flange, 8-First online pH meter, 9-Ultrasonic transducer, 10-Ultrasonic transducer chute, 11-Moving seat, 12-Buffer pad, 13-Limiting hole, 14-Ultrasonic generator, 15-Sound field action groove, 16-High frequency cable, 17-Sound insulation board, 18-PLC automatic control module, 1 9-Left-handed spiral blade, 20-Right-handed spiral blade, 21-Heterogeneous Fenton reactor, 22-Heterogeneous direct oxidation transfer reactor, 23-Cyclone separator, 24-Catalyst reflux pipe, 25-Time control valve, 26-Catalyst cleaning chamber, 27-Second water inlet pipe, 28-Second water inlet pump, 29-Second water distributor, 30-Nano catalyst dosing port, 31-Persulfate solution dosing port, 32-Second static mixing element, 33-Second flange, 34-Second online pH meter. Detailed Implementation

[0090] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0091] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0092] Example 1

[0093] This embodiment provides a heterogeneous Fenton-like reactor, such as Figures 1-3 As shown, the reactor includes a first inlet water system, a first static mixing catalytic oxidation pipeline, and a first static mixing element 6. One end of the first static mixing catalytic oxidation pipeline is connected to the first inlet water system, and the other end has an outlet. The first static mixing element 6 is disposed inside the first static mixing catalytic oxidation pipeline. The first static mixing element 6 has Fenton-like catalytic reaction activity. The inner diameter of the first static mixing catalytic oxidation pipeline is 0.125 m, and the length-to-inner-diameter ratio is 200:1. The operating pressure of the heterogeneous Fenton-like reactor is 10 kg / cm³. 2 Under the combined action of heterogeneous catalysis by the first static mixed element 6, which has Fenton-like catalytic activity, and homogeneous catalysis by FeSO4 solution, hydrogen peroxide decomposes to produce reactive oxygen species, which oxidize and decompose the recalcitrant organic matter in the wastewater.

[0094] The first static mixed catalytic oxidation pipeline is composed of 12 first pipeline units connected together, and the first pipeline units are connected to each other by a first flange 7.

[0095] The first static mixed catalytic oxidation pipeline has three sets arranged in parallel.

[0096] The first static mixing element 6 is an SK-type static mixing element, with the structure as follows: Figure 2 As shown, it is composed of alternating left-handed spiral blades 19 and right-handed spiral blades 20. The first static mixing element 6 is manufactured by 3D printing from iron-manganese bimetallic oxide. The SK-type static mixing element is manufactured as a single piece, which facilitates disassembly and installation and is less prone to clogging. The first static mixing element 6 is detachably installed inside the first static mixing catalytic oxidation pipeline and is not discontinuously arranged. The total length of the first static mixing element 6 is approximately 1 / 4 of the length of the first static mixing catalytic oxidation pipeline, ensuring that the first static mixing element 6, which has Fenton-like catalytic reaction activity, has sufficient contact time with the wastewater while maintaining low pressure loss and saving energy.

[0097] The heterogeneous Fenton reactor in this embodiment also includes a first dosing system; the first dosing system includes an acidified FeSO4 solution dosing port 4, a hydrogen peroxide dosing port 5, a first dosing metering pump, and a first online pH meter 8; the first online pH meter 8 is interlocked with the acid dosing pump used to prepare the acidified FeSO4 solution, so as to accurately control the reaction pH and the amount of dosing.

[0098] The first water inlet system includes a first water inlet pump 2, a first water inlet pipe 1, and a first water distributor 3; the first water inlet pump 2 and the first water distributor 3 are connected through the first water inlet pipe 1, and the outlet of the first water distributor 3 is connected to each first static mixing catalytic oxidation pipeline.

[0099] The acidified FeSO4 solution inlet 4 and the hydrogen peroxide inlet 5 are located on the first static mixing catalytic oxidation pipeline, after the first water distributor 3 and before the inlet of the first static mixing element 6.

[0100] like Figure 3 As shown, the heterogeneous Fenton reactor of this embodiment also includes an ultrasonic cleaning system. The ultrasonic cleaning system includes an ultrasonic generator 14, an ultrasonic transducer 9, a sound field interaction tank 15, a slide for the ultrasonic transducer 9, and a PLC automatic control module 18. The ultrasonic generator 14 emits a high-frequency AC signal, driving the ultrasonic transducer 9 to generate high-frequency mechanical vibration. This high-frequency mechanical vibration propagates through the sound field interaction tank 15 and the first static mixing catalytic oxidation pipeline to the fluid within the first static mixing catalytic oxidation pipeline, generating a cavitation effect. The ultrasonic transducer 9 is connected to the ultrasonic generator 14 via a high-frequency cable 16. The ultrasonic cleaning effectively slows down the deposition and adhesion of iron sludge generated by the reaction of FeSO4 and hydrogen peroxide on the surface of the first static mixing element 6, extending the service life of the first static mixing element 6 and reducing its replacement frequency. Simultaneously, the ultrasonic cavitation effect enhances the reaction of reactive oxygen species, enabling more effective oxidative decomposition of recalcitrant organic matter in the wastewater. The ultrasonic transducer chute 10 is a rectangular chute located below the first static mixing catalytic oxidation pipeline. Under the control of the PLC automatic control module 18, the ultrasonic transducer 9 can automatically move horizontally along the ultrasonic transducer chute 10 with the moving seat 11, expanding the effective range of the ultrasonic transducer 9 along the first static mixing catalytic oxidation pipeline and significantly improving cleaning and catalytic efficiency. Several limiting holes 13 are provided inside the ultrasonic transducer chute 10, which cooperate with the limiting rod to lock the ultrasonic transducer 9. Depending on the length of the first static mixing catalytic oxidation pipeline, multiple independently moving ultrasonic transducers 9 can be installed on one pipeline. By editing the PLC automatic control program, parameters such as the moving speed, cleaning time, and stationary time of the ultrasonic transducer 9 can be adjusted. The ultrasonic transducer 9 contacts the buffer pad 12, which reduces the noise generated by the vibration of the ultrasonic transducer 9 to a certain extent. Simultaneously, a sound field effect groove 15 is provided, which is separated from the external environment by a sound insulation plate 17. Melamine sound-absorbing cotton is arranged on the inner side of the sound insulation plate 17 to improve the noise reduction effect.

[0101] The first static mixing catalytic oxidation pipeline is made of 316L stainless steel.

[0102] Example 2

[0103] This embodiment provides a method for advanced treatment of biochemically treated coking wastewater using a heterogeneous Fenton reactor as described in Example 1:

[0104] The coking wastewater after biochemical treatment has a COD of 258 mg / L and a pH of 7.2. It is pumped into the first inlet pipe 1 by the first inlet pump 2 and then evenly distributed in the three parallel first static mixing catalytic oxidation pipes through the first water distributor 3.

[0105] During reactor operation, acidified FeSO4 solution and hydrogen peroxide are introduced into the corresponding FeSO4 solution inlet 4 and hydrogen peroxide inlet 5 via the first metering pump. Under the segmentation and mixing action of the first static mixing element 6, they achieve rapid and sufficient contact with the wastewater. The dosage of acidified FeSO4 solution is 240 mg / L, and the dosage of hydrogen peroxide is 180 mg / L. The acid dosing pump involved in the preparation of the FeSO4 solution is interlocked with an online pH meter located in the wastewater mixing section to control the wastewater pH at 5.2. The wastewater flows through the entire heterogeneous Fenton reactor within 10 minutes, completing efficient catalytic oxidation degradation, and the effluent COD is stably reduced to below 50 mg / L.

[0106] Example 3

[0107] This embodiment provides a heterogeneous Fenton reactor, with a structure basically the same as that of Embodiment 1, except that this embodiment does not include an ultrasonic cleaning system. If the first static mixing element 6 exhibits caking and passivation, resulting in reduced catalytic efficiency, the heterogeneous Fenton reactor is inspected and maintained, and a new first static mixing element 6 is replaced. The replaced first static mixing element 6 is then acid-washed and reshaped to achieve regeneration.

[0108] Example 4

[0109] This embodiment provides a treatment device for recalcitrant organic wastewater, such as... Figure 4 As shown, the system includes the heterogeneous Fenton reactor 21 of Example 1, as well as the heterogeneous direct oxidation transfer reactor 22 and the nanocatalyst cleaning and recovery system. The heterogeneous Fenton reactor 21 and the heterogeneous direct oxidation transfer reactor 22 are connected in series, and the outlet of the heterogeneous Fenton reactor 21 is connected to the inlet of the heterogeneous direct oxidation transfer reactor 22.

[0110] The nanocatalyst cleaning and recovery system is connected to the heterogeneous direct oxidation transfer reactor 22. The nanocatalyst cleaning and recovery system includes a hydrocyclone separator 23, a catalyst return pipe 24, a catalyst cleaning chamber 26, and a time control valve 25. The outlet of the heterogeneous direct oxidation transfer reactor 22 is connected to the hydrocyclone separator 23. The nanocatalyst with pollutants enriched on its surface and the deeply purified wastewater enter the hydrocyclone separator 23 to achieve solid-liquid separation. The separated nanocatalyst enters the catalyst return pipe 24. The time control valve 25 is installed on the catalyst return pipe 24 to control the nanocatalyst discharged from the hydrocyclone separator 23 to enter the catalyst cleaning chamber 26 for cleaning and regeneration or to be directly returned to the heterogeneous direct oxidation transfer reactor 22.

[0111] like Figure 5 As shown, the heterogeneous direct oxidation transfer reactor 22 includes a second inlet system, a second static mixing catalytic oxidation pipeline, and a second static mixing element 32. One end of the second static mixing catalytic oxidation pipeline is connected to the second inlet system, and the other end is provided with an outlet. The second static mixing element 32 is disposed inside the second static mixing catalytic oxidation pipeline. The inner diameter of the second static mixing catalytic oxidation pipeline is 0.125 m, and the length-to-inner-diameter ratio is 200:1. The operating pressure of the heterogeneous direct oxidation transfer reactor 22 is 10 kg / cm³. 2 .

[0112] The second static mixed catalytic oxidation pipeline is composed of six second pipeline units connected together, and the second pipeline units are connected to each other via second flanges 33. Three sets of the second static mixed catalytic oxidation pipeline are arranged in parallel.

[0113] The heterogeneous direct oxidation transfer reactor 22 also includes a second dosing system; the second dosing system includes a nanocatalyst dosing port 30, a persulfate solution dosing port 31, a second dosing metering pump, and a second online pH meter 34.

[0114] The second water inlet system includes a second water inlet pump 28, a second water inlet pipe 27, and a second water distributor 29; the second water inlet pump 28 and the second water distributor 29 are connected through the second water inlet pipe 27, and the outlet of the second water distributor 29 is connected to each of the second static mixing catalytic oxidation pipelines.

[0115] The nanocatalyst inlet 30 and the persulfate solution inlet 31 are located after the second water distributor 29 and before the inlet of the second static mixing element 32.

[0116] The second static mixing element 32 is made of polytetrafluoroethylene (PTFE), which does not adsorb the nanocatalyst and has no catalytic activity, but promotes the thorough mixing of pollutants, persulfate solution, and nanocatalyst. The second static mixing element 32 is 1.5 m long.

[0117] The second static mixing element 32 is an SK-type static mixing element; the second static mixing element 32 is detachably disposed inside the second static mixing catalytic oxidation pipeline;

[0118] The second static mixing catalytic oxidation pipeline is made of 316L stainless steel.

[0119] Example 5

[0120] This embodiment provides a method for treating recalcitrant organic wastewater, using the apparatus of Example 4. The recalcitrant organic wastewater is biochemically treated wastewater from a chemical industrial park, with a COD of 325 mg / L and a pH of 7.5. The method includes the following steps:

[0121] S1. Pump the recalcitrant organic wastewater into the heterogeneous Fenton reactor 21;

[0122] S2. Add acidified FeSO4 solution at a dosage of 145 mg / L; add hydrogen peroxide at a dosage of 110 mg / L to control the pH of the recalcitrant organic wastewater to 5.4; the acidified FeSO4 solution is a FeSO4 solution pre-acidified with sulfuric acid; the residence time of the recalcitrant organic wastewater in the heterogeneous Fenton reactor 21 is 10 min. The COD of the effluent from the heterogeneous Fenton reactor 21 is reduced to 159 mg / L.

[0123] S3. Pump the effluent from step S2 into the heterogeneous direct oxidation transfer reactor 22;

[0124] S4. Add 1.0 g / L of nano-iron-manganese oxide catalyst and 40 mg / L of persulfate (PMS). The wastewater residence time in the heterogeneous direct oxidation transfer reactor 22 is 10 min. The COD of the effluent in the heterogeneous direct oxidation transfer reactor 22 is stably reduced to below 35 mg / L.

[0125] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A heterogeneous Fenton-like reactor, characterized in that, It includes a first water inlet system, a first static mixing catalytic oxidation pipeline, and a first static mixing element; One end of the first static mixing catalytic oxidation pipeline is connected to the first water inlet system, and the other end is provided with a water outlet; The first static mixing element is disposed inside the first static mixing catalytic oxidation pipeline; The first static mixing element has Fenton-like catalytic reaction activity; the first static mixing element is made of one or more of iron, manganese, copper, nickel, or their metal oxides; the first static mixing element is an SL-type static mixing element, an SX-type static mixing element, or an SK-type static mixing element. The ratio of the length to the inner diameter of the first static mixed catalytic oxidation pipe is 20:1 to 200:1; The heterogeneous Fenton reactor satisfies at least one of the following conditions: (1) Multiple first static mixed catalytic oxidation pipelines are arranged in parallel; (2) It also includes a first dosing system; The first dosing system includes an acidified FeSO4 solution dosing port, a hydrogen peroxide dosing port, a first dosing metering pump, and a first online pH meter; The acidified FeSO4 solution inlet and the hydrogen peroxide inlet are located between the first water inlet system and the first static mixing element; (3) The first water inlet system includes a first water inlet pump, a first water inlet pipe and a first water distributor; the first water inlet pump and the first water distributor are connected through the first water inlet pipe, and the outlet of the first water distributor is connected to each of the first static mixing catalytic oxidation pipelines. (4) The first static mixing element is detachably disposed in the first static mixing catalytic oxidation pipeline.

2. The heterogeneous Fenton reactor according to claim 1, characterized in that, It also includes an ultrasonic cleaning system, which comprises an ultrasonic generator, an ultrasonic transducer, and an acoustic field treatment tank.

3. The heterogeneous Fenton reactor according to claim 2, characterized in that, The ultrasonic cleaning system further includes an ultrasonic transducer slide, along which the ultrasonic transducer can move; and / or The ultrasonic cleaning system is equipped with a sound insulation panel. And / or, the ultrasonic transducer is designed with a noise reduction structure.

4. A treatment device for recalcitrant organic wastewater, characterized in that, The reactor includes the heterogeneous Fenton reactor as described in any one of claims 1-3, and further includes a heterogeneous direct oxidation transfer reactor, wherein the heterogeneous Fenton reactor and the heterogeneous direct oxidation transfer reactor are connected in series.

5. The treatment apparatus for recalcitrant organic wastewater according to claim 4, characterized in that, It also includes a nanocatalyst cleaning and recovery system connected to the heterogeneous direct oxidation transfer reactor; The nanocatalyst cleaning and recovery system includes a hydrocyclone separator, a catalyst return pipe, a catalyst cleaning chamber, and a time control valve. The outlet of the heterogeneous direct oxidation transfer reactor is connected to the cyclone separator. The separated nanocatalyst enters the catalyst return pipe. The time control valve set on the catalyst return pipe controls the separated nanocatalyst to enter the catalyst cleaning chamber for cleaning and regeneration or to be directly returned to the heterogeneous direct oxidation transfer reactor.

6. The treatment apparatus for recalcitrant organic wastewater according to claim 4 or 5, characterized in that, The heterogeneous direct oxidation transfer reactor includes a second inlet system, a second static mixing catalytic oxidation pipeline, and a second static mixing element; One end of the second static mixing catalytic oxidation pipeline is connected to the second water inlet system, and the other end is provided with a water outlet; The second static mixing element is disposed inside the second static mixing catalytic oxidation pipeline; The ratio of the length to the inner diameter of the second static mixed catalytic oxidation pipe is 20:1 to 200:

1.

7. The treatment apparatus for recalcitrant organic wastewater according to claim 6, characterized in that, The heterogeneous direct oxidation transfer reactor satisfies at least one of the following conditions: (1) Multiple second static mixed catalytic oxidation pipelines are arranged in parallel; (2) It also includes a second dosing system; The second dosing system includes a nanocatalyst dosing port, a persulfate solution dosing port, a second dosing metering pump, and a second online pH meter; The nanocatalyst inlet and the persulfate solution inlet are located between the second water inlet system and the second static mixing element. (3) The second water inlet system includes a second water inlet pump, a second water inlet pipe and a second water distributor; the second water inlet pump and the second water distributor are connected through the second water inlet pipe, and the outlet of the second water distributor is connected to each of the second static mixing catalytic oxidation pipelines. (4) The material of the second static mixing element is polytetrafluoroethylene; (5) The second static mixing element is an SL-type static mixing element, an SX-type static mixing element, or an SK-type static mixing element; (6) The second static mixing element is detachably disposed in the second static mixing catalytic oxidation pipeline.

8. A method for treating recalcitrant organic wastewater using the treatment apparatus according to any one of claims 4-7, characterized in that, The process includes the following steps: subjecting the recalcitrant organic wastewater to a heterogeneous Fenton-like reaction first, followed by a heterogeneous direct oxidation-transfer reaction.

9. The method for treating recalcitrant organic wastewater according to claim 8, characterized in that, In the heterogeneous Fenton reaction process, the pH of the recalcitrant organic wastewater is controlled at 5.0~5.5 using acidified FeSO4 solution and hydrogen peroxide; the heterogeneous Fenton reaction time is 1~15 min.

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