A heterogeneous fenton oxidation reaction device and wastewater treatment method

Abstract

The present application relates to wastewater treatment technical field, specifically to a kind of heterogeneous fenton oxidation reaction device and wastewater treatment method;The device includes spatial three-dimensional metal framework, spatial three-dimensional metal framework inside is equipped with cavity, at least including one metal ring, metal ring is equipped with several holes passing through the metal ring, the component of metal ring includes single metal and / or metal oxide with catalytic effect;It also includes water distributor, the water outlet of water distributor is arranged in the cavity inside the spatial three-dimensional metal framework.The device can strengthen the micro-contact area of organic matter in wastewater and fenton reagent, and make mixed liquid and metal ring fully contact, increase the contact time of reactants, the rate of transmission and mixing reaction process can be increased by 1-3 times, the material mixing and reaction time is greatly shortened, energy consumption is reduced, reagent dosage is saved, the utilization efficiency of reagent is improved, catalyst catalytic efficiency, and the advantages of small floor space.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a heterogeneous Fenton oxidation reactor and a wastewater treatment method. Background Technology

[0002] Industries such as chemical, food, metallurgy, electroplating, textile printing and dyeing, mining, papermaking, leather, pharmaceutical, and petroleum generate large amounts of wastewater and waste liquid during production processes, i.e., industrial wastewater. This wastewater mainly contains industrial raw materials, intermediate products, and pollutants lost during production. Due to its complex types and diverse components, most of which are difficult to degrade and possess a certain degree of toxicity, achieving a suitable balance between treatment to meet emission standards and cost control is a significant challenge and is widely recognized as a major problem in the field.

[0003] Currently, advanced oxidation technologies are used to treat high-concentration industrial wastewater. These technologies utilize activated carbon to oxidize, decompose, and mineralize most organic matter in the wastewater, achieving efficient removal of recalcitrant organic compounds. Activated carbon adsorption, ozone oxidation, and Fenton oxidation are the main methods. However, activated carbon adsorption requires large amounts of activated carbon, resulting in high recycling and regeneration costs and potential environmental impact. Ozone oxidation, on the other hand, is selective for pollutants and struggles to completely decompose recalcitrant organic compounds. The oxidation products are often small-molecule carboxylic acids, ketones, and aldehydes. For example, CN114262117A discloses a system for deep COD degradation of organic wastewater, including a raw water tank, oxygen cylinders, an ozone generator, a rotating packed bed (RPB) reactor, an intermediate equalization tank, an air pump, a storage tank, and a sequencing batch reactor (SBR). This patent involves a gas-liquid two-phase mixture, and the ozone oxidation process is selective, only treating a portion of the organic matter. For some recalcitrant organic compounds, such as benzene and toluene, the treatment effect is not ideal. The principle of Fenton oxidation is through Fe... 2+ The process of reacting with H2O2 under acidic conditions to generate strong oxidizing hydroxyl radicals (·OH) to degrade organic pollutants has the advantages of simple operation, applicability to a wide range of pollutants, and low risk of secondary pollution. It is a promising technology for treating recalcitrant organic pollutants.

[0004] Fenton oxidation includes homogeneous and heterogeneous Fenton oxidation. Homogeneous Fenton oxidation has a narrow pH range, cannot fully mineralize organic matter, has low H2O2 utilization, and generates a large amount of iron sludge during treatment, increasing costs. In contrast, heterogeneous Fenton oxidation is a typical catalytic oxidation reaction that occurs at the liquid-solid interface. Its principle is that the metal cations on the surface of the solid catalyst react with H2O2 to generate highly oxidizing ·OH. ·OH degrades organic pollutants through three mechanisms: electrophilic addition with double bonds or aromatic rings, hydrogen extraction from alkyl or hydroxyl groups, and electron transfer reactions. It has high hydrogen peroxide utilization, does not generate large amounts of iron sludge, has a wider pH range, and lower costs, making it a current research hotspot in the field of wastewater treatment.

[0005] Fully leveraging the liquid-solid mass transfer characteristics of the heterogeneous Fenton oxidation system is key to determining the overall treatment effect and operating cost of the heterogeneous Fenton reaction process.

[0006] Existing technologies primarily focus on the catalyst itself, improving pollutant removal efficiency by enhancing the catalyst's performance. For example, Chinese patent applications CN115869950A, CN115814796A, CN113856680A, and CN110465300A all start from the catalyst itself, developing solid-phase catalysts with large specific surface areas to increase the liquid-solid contact area, thereby improving the removal efficiency of recalcitrant pollutants. However, the disadvantage of solid-phase catalysts with large specific surface areas is their high density, rapid settling in liquids, and poor fluidization effect.

[0007] Besides optimizing the performance of the catalyst itself, high catalytic oxidation efficiency can also be achieved by optimizing the macro-mixing process, increasing the contact area between the catalyst and the reaction system, and enhancing the reaction process. Conventional techniques for optimizing the macro-mixing process mainly involve optimizing the reactor configuration or using mechanical stirring, increasing reflux, or increasing aeration to increase the contact degree between the liquid and the solid catalyst by increasing liquid disturbance. For example, CN107640854A discloses "An integrated method for deep treatment of dyeing and printing wastewater with oxidation time measured in seconds," and CN107473453A discloses "A novel pure fluid static pipeline reactor." These methods use water jets and static mixers as reagent mixing methods to achieve extremely short catalytic oxidation reactions, saving space and cost in tower construction. However, this type of reactor has the following problems: (1) It is essentially a homogeneous Fenton oxidation reaction with a narrow pH range, a large amount of reagent consumption, and low catalytic efficiency; (2) In actual wastewater treatment plants with a capacity of 10,000 tons, the required length and floor space of the mixing pipeline due to the residence time are large, which places high demands on the site; (3) The long mixing pipeline has a large resistance loss along the way and at bends, and in many cases, it is necessary to set up an additional inlet pump or booster pump to ensure that the wastewater can flow in and out smoothly, which increases the energy consumption of the entire reaction process.

[0008] In actual operation, dead zones and short-circuiting phenomena still exist within the reactor of the macro-mixing process. Furthermore, the methods for optimizing the macro-reaction process are often crude, resulting in poor fluidization and low utilization of solid-phase catalysts, as well as large reagent dosages. Simultaneously, in traditional heterogeneous catalytic reactions, catalysts are prone to caking and passivation, leading to significant catalyst deactivation and waste, thus affecting catalytic efficiency.

[0009] In summary, the macroscopic mixing process in heterogeneous Fenton oxidation reactors suffers from long reaction times, large dimensions, large footprint, poor fluidization, and severe caking and deactivation. Furthermore, the high energy consumption resulting from secondary lifting and mechanical / aeration mixing methods makes them environmentally unfriendly. Summary of the Invention

[0010] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art in the treatment of wastewater by heterogeneous Fenton reaction, such as large equipment footprint, high energy consumption, large amount of reagent required, low utilization rate of solid catalyst and easy occurrence of caking and passivation phenomenon, so as to provide a heterogeneous Fenton oxidation reaction device and wastewater treatment method.

[0011] Therefore, the present invention provides the following technical solution:

[0012] This invention provides a heterogeneous Fenton oxidation reaction device, comprising a spatial three-dimensional metal framework with an internal cavity. The spatial three-dimensional metal framework includes at least one metal ring, specifically, it may include one, two, three, four, five, or several metal rings, with no specific limitation on the number, preferably three to seven. Each metal ring has several through holes. The metal ring is composed of a catalytically active elemental metal and / or metal oxide. The elemental metal includes at least one of iron, manganese, copper, and nickel. The metal oxide includes at least one of iron oxide, manganese oxide, copper oxide, and nickel oxide. The material of the metal ring may be, but is not limited to, iron, manganese, copper, nickel, iron(III) oxide, manganese(III) oxide, etc. A water distributor is also included, with its outlet located in the cavity inside the spatial three-dimensional metal framework.

[0013] Preferably, the plurality of metal rings in the spatial three-dimensional metal frame are arranged concentrically.

[0014] Preferably, the metal ring comprises at least one layer of metal mesh, which encloses and forms the metal ring. Further, the metal ring may comprise one, two, three, or other layers of metal mesh without a specific limitation on the number; when the metal ring comprises multiple layers of metal mesh, the multiple layers of metal mesh are fixedly connected and enclosed to form the metal ring.

[0015] Preferably, the heterogeneous Fenton oxidation reactor further includes a housing, and the spatial three-dimensional metal skeleton is disposed inside the housing;

[0016] Preferably, the thickness of the metal ring is 1 / 15 to 7 / 10 of the radius of the outer shell.

[0017] Preferably, the metal mesh is composed of crisscrossing metal wires.

[0018] Preferably, the pores formed by the crisscrossing metal wires are holes that penetrate the metal ring.

[0019] Preferably, the metal wire is made of the elemental metal and / or the metal oxide. The material of the metal ring can be, but is not limited to, iron, manganese, copper, nickel, iron(III) oxide, manganese(III) oxide, etc. When the material of the metal ring includes multiple components, their proportions can be arbitrary; when the metal ring includes two optional components, the mass ratio can be arbitrary; for example, the metal ring includes both iron and manganese, the metal ring includes iron(III) oxide and manganese, the metal ring includes iron(III) oxide and manganese(III) oxide; as another example, the mass ratio of the two optional components is 5:3, 3:7, 6:1, 8:3, etc.

[0020] Furthermore, the cross-sectional shape of the metal wire is polygonal or circular. The polygon can be, but is not limited to, triangle, quadrilateral, pentagon, etc. When the cross-sectional shape of the metal wire is polygonal, the shearing effect can be further enhanced because the metal wire has edges and corners.

[0021] Preferably, when the cross-sectional shape of the metal wire is circular, the diameter of the metal wire is 1.2 to 4.0 mm.

[0022] Optionally, the spacing between adjacent metal rings in the spatial three-dimensional skeleton can be set at equal intervals or at non-equal intervals, depending on actual needs.

[0023] Preferably, the metal rings are spaced at equal intervals.

[0024] Preferably, the shortest distance between adjacent metal rings is 1 / 5 to 1 / 3 of the radius of the cavity.

[0025] Preferably, the water distributor has at least three openings for conveying the mixture inside the water distributor to the spatial three-dimensional metal frame, where the mixture is subjected to shear force and undergoes a Fenton oxidation reaction. The shape of the openings can be, but is not limited to, circular, rectangular, etc. Preferably, the water distributor has 3 to 9 openings.

[0026] Preferably, the water distributor is positioned in the axial direction of the spatial three-dimensional metal frame.

[0027] Preferably, the system further includes a macro mixer connected to the water distributor; the macro mixer includes a tube and several fins, the fins dividing the conveying section of the tube, the fins being arranged along the extension direction of the tube, and adjacent fins being arranged at a predetermined angle; preferably, the fins are spiral, circular, or square in shape. Specifically, the fin material includes 316L stainless steel, and the predetermined angle between adjacent fins can be, but is not limited to, 90°, 120°, or 135°; the diameter of the macro mixer is 0.1–1.2 m.

[0028] Preferably, the heterogeneous Fenton oxidation reaction apparatus further includes at least one ultrasonic vibrator. Further, in this apparatus, the number of ultrasonic vibrators can be, but is not limited to, one, two, three, four, etc.

[0029] Preferably, the ultrasonic vibrator is fixed to the outer wall of the spatial three-dimensional metal frame. When there are two ultrasonic vibrators, they can be symmetrically arranged on the outer wall of the device, or they can be asymmetrically arranged on the outer wall of the device.

[0030] Preferably, the heterogeneous Fenton oxidation reactor further includes a rotating shaft that passes through the outer shell and is connected to the spatial three-dimensional metal frame, used to drive the spatial three-dimensional metal frame to rotate, so that the wastewater inside the cavity can fully contact and shear the metal mesh under the action of centrifugal force to form tiny droplets; and a motor to provide electrical energy.

[0031] Preferably, the heterogeneous Fenton oxidation reactor further includes a water inlet pipe connected to a water distributor; the water inlet pipe is provided with a wastewater inlet and a Fenton reagent inlet; and a wastewater outlet is located at the bottom of the outer casing.

[0032] The present invention also provides a wastewater treatment method using the above-mentioned heterogeneous Fenton oxidation reactor, comprising the following steps: mixing the pH-adjusted wastewater with Fenton reagent, and conveying the mixture to the rotary heterogeneous Fenton oxidation reactor for Fenton oxidation reaction.

[0033] Preferably, the Fenton reagent comprises FeSO4 and H2O2.

[0034] Preferably, the dosage of FeSO4 is 150–250 mg / L.

[0035] Preferably, the dosage of H2O2 is 100-200 mg / L.

[0036] Preferably, the reaction time of the mixture in the heterogeneous Fenton oxidation reactor is 30s to 120s.

[0037] Preferably, the pH value of the wastewater after pH adjustment is 5.0 to 5.5.

[0038] Preferably, the frequency of the ultrasonic vibrator is 40–80 kHz and the power is 30–1500 W.

[0039] Preferably, the ultrasonic vibrator operates intermittently or continuously.

[0040] Preferably, the frequency of intermittent operation of the ultrasonic vibrator is 6h / time to 12h / time.

[0041] Preferably, the rotation speed of the spatial three-dimensional metal frame is 800 to 3500 rpm.

[0042] The technical solution of this invention has the following advantages:

[0043] 1. Regarding microscopic mixing reactions, the present invention provides a heterogeneous Fenton oxidation reaction device, which includes a spatial three-dimensional metal framework and a water distributor. The spatial three-dimensional metal framework has a cavity inside, and the spatial three-dimensional metal framework includes at least one metal ring with several holes penetrating the metal ring. The metal ring is composed of elemental metals and / or metal oxides with catalytic activity. The outlet of the water distributor is located in the cavity inside the spatial three-dimensional metal framework. Driven by a motor, the heterogeneous Fenton oxidation reaction device drives the three-dimensional metal framework to rotate at high speed. Under centrifugal force, the wastewater in the cavity comes into full contact with and is sheared against the metal mesh, forming numerous tiny droplets. This enhances the microscopic contact area between the organic matter in the wastewater and the Fenton reagent, and ensures full contact between the mixture and the metal ring, increasing the contact time of the reactants. This can increase the rate of the transfer and mixing reaction process by 1-3 times, significantly shortening the material mixing and reaction time, reducing energy consumption, saving reagent dosage, improving reagent utilization efficiency, and catalyst catalytic efficiency. The device of the present invention also has the advantage of small footprint.

[0044] The spatial three-dimensional metal framework includes at least one metal ring, which itself has catalytic oxidation properties. The metal ring has pores penetrating it, forming channels among several metal rings, allowing the mixed liquid to fully contact all the metal rings in the spatial three-dimensional metal framework. As the spatial three-dimensional metal framework rotates, the mixed liquid, upon entering the framework under centrifugal force, is subjected to shear force. The shearing force is further amplified by the pores in the metal rings, breaking the mixed liquid into fine droplets. This increases the specific surface area of ​​the mixed liquid, and the significant turbulent disturbance enhances the mass transfer process. The mixed liquid is highly sheared and dispersed, forming droplets with exceptionally large specific surface areas, down to the molecular scale. This ensures the mixed liquid is uniformly dispersed within the device, allowing for full contact with the catalytically active metal rings in the spatial three-dimensional metal framework, thus improving mass transfer efficiency, enhancing catalytic and reaction efficiency, strengthening the Fenton oxidation reaction, effectively increasing the removal rate of recalcitrant organic pollutants, shortening reaction time, reducing reagent dosage, and decreasing subsequent iron sludge production.

[0045] Since the metal ring component contains catalytically active elemental metals and / or metal oxides, the metal ring has catalytic reaction activity and abundant catalytic active sites, which can take into account the functions of efficient shearing, mixing and catalysis, further shortening the reaction time and reducing the subsequent iron sludge production.

[0046] 2. Regarding macroscopic mixing reactions, the heterogeneous Fenton oxidation reactor provided by this invention includes a macroscopic mixer comprising a tube and several fins. The fins divide the conveying cross-section of the tube, and the fins are arranged along the extension direction of the tube. Adjacent fins are arranged at a predetermined angle. Preferably, the fins are spiral, circular, or square in shape. The mixture continuously generates turbulent flow, vortices, and counter-vortices in the macroscopic mixer, promoting macroscopic and efficient mixing of the Fenton reagent and wastewater.

[0047] 3. The ultrasonic waves generated by the ultrasonic vibrator are longitudinal waves with alternating compression and sparsity. Through the cavitation effect of the ultrasound, a strong micro-perturbation effect is generated on the surface of the metal ring, which in turn disperses, emulsifies, and peels off the contaminant layer on the surface of the catalytically active metal ring, thereby achieving the purpose of cleaning the catalyst and solving the problem of severe catalyst caking and deactivation in the traditional heterogeneous Fenton oxidation reaction.

[0048] The mechanical and chemical effects generated by the cavitation of ultrasound improve the mass transfer and mixing efficiency in the reactor, enhance the generation process of active oxygen species, and accelerate the reaction rate. It also solves the problems of catalyst blockage and scaling caused by iron sludge generated by the reaction of FeSO4 and hydrogen peroxide, effectively slows down the caking phenomenon of catalytic active elements, and has self-cleaning ability.

[0049] 4. The wastewater treatment method provided by the present invention, by using the device of the present invention, can improve wastewater treatment efficiency, catalytic efficiency and reaction efficiency by enhancing the macroscopic and microscopic mixed reaction process, and significantly reduce the amount of reagents added. The method is applicable to systems with a pH of 5.0 to 5.5, and broadens the pH range applicable to wastewater treatment by traditional Fenton oxidation reaction. Attached Figure Description

[0050] 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.

[0051] Figure 1 This is a schematic diagram of the apparatus for treating wastewater by heterogeneous Fenton oxidation reaction according to the present invention;

[0052] Figure 2 This is a schematic diagram of a three-dimensional metal skeleton composed of concentric ring structures of the present invention;

[0053] Figure 3 This is a schematic diagram of the morphology of the metal mesh of the present invention;

[0054] Figure 4This is a schematic diagram of the internal structure of the macroscopic mixer of the present invention.

[0055] Explanation of reference numerals in the attached figures:

[0056] 1-Spatial three-dimensional metal frame; 2-Macroscopic mixer; 3-First ultrasonic vibrator; 4-Second ultrasonic vibrator; 5-Water distributor; 6-Rotating shaft; 7-Motor; 8-Outer shell; 9-Wastewater outlet; 10-Ferrous sulfate inlet; 11-Hydrogen peroxide inlet; 12-Wastewater inlet. Detailed Implementation

[0057] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0059] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0060] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0061] Example 1

[0062] This embodiment provides a heterogeneous Fenton oxidation reaction apparatus, such as... Figure 1 As shown, it includes:

[0063] A three-dimensional spatial metal framework 1 has an internal cavity. The three-dimensional spatial metal framework 1 includes at least one metal ring, and the metal ring has several holes penetrating the metal ring. The composition of the metal ring includes a catalytic elemental metal and / or metal oxide. The elemental metal includes at least one of iron, manganese, copper, and nickel, and the metal oxide includes at least one of iron oxide, manganese oxide, copper oxide, and nickel oxide. Specifically, the three-dimensional spatial metal framework 1 may include one, two, three, four, five, or several metal rings, and the number is not specifically limited, but preferably three to seven. The number of holes on the metal ring is not specifically limited. The material composition of the metal ring may include, but is not limited to, iron, manganese, copper, nickel, iron(III) oxide, and manganese(III) oxide.

[0064] Water distributor 5, the outlet of water distributor 5 is located inside the cavity.

[0065] As the spatial three-dimensional metal skeleton 1 rotates, under the action of centrifugal force, the mixed liquid discharged from the outlet of the water distributor 5 enters the spatial three-dimensional metal skeleton 1 and is subjected to shear force. Due to the presence of several holes in the metal ring, the shearing effect is further enhanced, and the mixed liquid is broken into fine droplets, increasing the specific surface area. The huge turbulent disturbance enhances the mass transfer process. The mixed liquid is highly sheared and dispersed, and reaches various positions of the spatial three-dimensional metal skeleton 1 through the holes, making full contact with the metal ring. The mass transfer effect is improved, the catalytic and reaction efficiency is increased, the removal rate of recalcitrant organic pollutants is effectively improved, the reaction time is shortened, the amount of reagent added is reduced, and the subsequent iron sludge production is reduced.

[0066] In a preferred embodiment, when the spatial three-dimensional metal frame 1 includes multiple metal rings, the multiple metal rings in the spatial three-dimensional metal frame 1 are concentrically arranged, such as... Figure 2 As shown. The spacing between adjacent metal rings can be set equally or unequally; preferably, it is set equally. Both the spacing and the setting method can be adjusted according to actual needs. Preferably, the shortest spacing between adjacent metal rings is 1 / 5 to 1 / 3. Further, the cavity corresponds to the internal space of the smallest metal ring, that is, the cavity radius corresponds to the inner diameter of the smallest metal ring.

[0067] In a preferred embodiment, the heterogeneous Fenton oxidation reactor further includes a housing 8, with a three-dimensional metal frame 1 disposed inside the housing 8; the thickness of the metal ring is 1 / 15 to 7 / 10 of the radius of the housing 8. The metal ring comprises at least one layer of metal mesh, which encloses the metal ring. The metal mesh is composed of several crisscrossing metal wires, and there are pores between the crisscrossing metal wires. These pores are holes that penetrate the metal ring, such as... Figure 3As shown. Further, the metal ring may include one, two, or three layers of metal mesh, without a specific limit on the number; when the metal ring includes multiple layers of metal mesh, the multiple layers of metal mesh are fixedly connected and enclosed to form the metal ring; the cross-sectional shape of the metal wire is polygonal or circular, and the polygon can be, but is not limited to, triangles, quadrilaterals, pentagons, etc. When the cross-sectional shape of the metal wire is polygonal, the shearing effect can be further enhanced due to the sharp edges of the metal wire. When the cross-sectional shape of the metal wire is circular, the diameter of the metal wire is 1.2–4.0 mm.

[0068] The metal wire comprises catalytically active elemental metals and / or metal oxides. The elemental metals include at least one selected from iron, manganese, copper, and nickel. The metal oxides include at least one selected from iron oxide, manganese oxide, copper oxide, and nickel oxide. Specifically, the material composition of the metal wire may include, but is not limited to, iron, manganese, copper, nickel, iron(III) oxide, and manganese(III) oxide. Furthermore, the metal ring has abundant active sites, combining efficient shearing, mixing, and catalytic functions, and possesses high mechanical strength, which can shorten the reaction time and reduce the subsequent iron sludge yield.

[0069] In a preferred embodiment, the water distributor 5 has at least three openings for conveying the mixture within the water distributor 5 to the spatial three-dimensional metal frame 1, where the mixture is subjected to shearing action and undergoes a Fenton oxidation reaction. Further, the water distributor 5 is positioned along the axial direction of the spatial three-dimensional metal frame 1. The shape of the openings can be, but is not limited to, circular, rectangular, etc. Preferably, the water distributor has 3 to 9 openings.

[0070] In a preferred embodiment, a macro mixer 2 is also included, which is connected to the water distributor 5; such as Figure 4 As shown, the macro mixer 2 includes a tube and several fins. The fins effectively cut the liquid transported in the tube. The fins are arranged along the extension direction of the tube, with adjacent fins at a predetermined angle. Preferably, the fins are spiral, circular, or square. Specifically, the fin material includes 316L stainless steel, and the predetermined angle between adjacent fins can be, but is not limited to, 90°, 120°, or 135°. The diameter of the macro mixer is 0.1–1.2 m. The mixed liquid continuously generates turbulent flow, vortices, and counter-vortices in the macro mixer 2, promoting macroscopic and efficient mixing of Fenton's reagent and wastewater.

[0071] In a preferred embodiment, at least one ultrasonic vibrator is further included, fixed to the outer wall of the spatial three-dimensional metal frame 1; further, the ultrasonic vibrator is positioned between the metal rings; further, in this device, the number of ultrasonic vibrators can be, but is not limited to, 1, 2, 3, 4, etc.; when there are 2 ultrasonic vibrators, they can be symmetrically arranged in the device. Through the cavitation effect of ultrasound, a strong micro-perturbation effect is generated on the surface of the metal rings, thereby dispersing, emulsifying, and peeling off the contaminant layer on the surface of the catalytically active metal rings, thus achieving the purpose of cleaning the catalyst, and solving the problems of severe catalyst caking and deactivation, blockage caused by iron sludge, and structural issues in the traditional heterogeneous Fenton oxidation reaction, thus exhibiting a self-cleaning effect.

[0072] As a preferred embodiment, it further includes:

[0073] The pivot 6 passes through the outer shell 8 and is connected to the spatial three-dimensional metal frame 1, driving the spatial three-dimensional metal frame 1 to rotate.

[0074] Motor 7 provides electrical energy to make the three-dimensional metal frame 1 rotate.

[0075] The water inlet pipe is connected to the water distributor 5; the water inlet pipe is equipped with a wastewater inlet 12 and a Fenton reagent inlet; specifically, the water inlet pipe is equipped with a wastewater inlet 12, a ferrous sulfate inlet 10 and a hydrogen peroxide inlet 11;

[0076] Wastewater outlet 9 is located at the bottom of the outer casing 8.

[0077] The device provided in this embodiment enhances the microscopic contact area between organic matter and Fenton's reagent in wastewater, increases the contact time of reactants, and has a good fluidization effect. It can increase the rate of transfer and mixing reaction by 1-3 times, significantly shorten the material mixing and reaction time, reduce energy consumption, save reagent dosage, improve reagent utilization efficiency and catalyst catalytic efficiency. The device of this invention also has the advantages of small footprint and does not involve high energy consumption problems such as aeration and secondary lifting.

[0078] Furthermore, the device provided by the present invention can be used for pretreatment before biochemical treatment, and can also be applied to the advanced treatment of recalcitrant organic wastewater after biochemical treatment.

[0079] Example 2

[0080] This embodiment provides a wastewater treatment method, specifically for treating wastewater from petrochemical biochemical treatment processes. The wastewater has a COD of 548 mg / L, and the method utilizes the apparatus provided in Embodiment 1. This apparatus specifically includes:

[0081] The spatial three-dimensional metal skeleton 1 has an internal cavity. The spatial three-dimensional metal skeleton 1 includes 5 concentric metal rings. The thickness of the metal rings is 1 / 5 of the radius of the outer shell. Each metal ring has several holes that penetrate the metal ring. The spacing between adjacent metal rings is equally spaced, with the shortest spacing being 1 / 5 of the radius of the internal cavity of the spatial three-dimensional metal skeleton. The radius of the cavity is the inner diameter of the smallest metal ring. The metal rings are composed of 5 layers of metal mesh connected together. The metal mesh is composed of several crisscrossing metal wires with a diameter of 2.0 mm. There are gaps between the crisscrossing metal wires, which are the holes that penetrate the metal rings. The metal wires are made of iron oxide and elemental manganese metal in a mass ratio of 3:7.

[0082] Water distributor 5, the outlet of water distributor 5 is located inside the cavity; water distributor 5 has 3 openings, so that the mixed liquid enters the spatial three-dimensional metal frame 1 in the form of liquid column, and the openings are circular in shape.

[0083] Two ultrasonic vibrators, a first ultrasonic vibrator 3 and a second ultrasonic vibrator 4, are symmetrically fixed to the outer wall of the three-dimensional metal frame 1.

[0084] The outer shell 8 houses the three-dimensional metal frame 1.

[0085] The pivot 6 passes through the outer shell 8 and is connected to the spatial three-dimensional metal frame 1, driving the spatial three-dimensional metal frame 1 to rotate.

[0086] Motor 7 provides electrical energy to make the three-dimensional metal frame 1 rotate.

[0087] The water inlet pipe is connected to the water distributor 5; the water inlet pipe is equipped with a wastewater inlet 12, a ferrous sulfate inlet 10 and a hydrogen peroxide inlet 11.

[0088] Wastewater outlet 9 is located at the bottom of the outer casing 8.

[0089] Wastewater treatment methods include the following steps:

[0090] (1) Add concentrated sulfuric acid to adjust the pH of the wastewater to 5.1, and then let the wastewater flow into the inlet pipe through the wastewater inlet 12;

[0091] (2) Add solid ferrous sulfate to ferrous sulfate inlet 10 so that 180 mg of ferrous sulfate is added to each 1 L of wastewater. Add 30% hydrogen peroxide solution to hydrogen peroxide inlet 11 so that 180 mg of hydrogen peroxide is added to each 1 L of wastewater. Approximately 600 mg of hydrogen peroxide solution is added.

[0092] (3) The wastewater after adding ferrous sulfate and hydrogen peroxide enters the spatial three-dimensional metal skeleton 1 through the water distributor 5; wherein, the mixing time of the mixture formed by the wastewater and Fenton reagent in the macro mixer is 12s;

[0093] (4) Set the rotation speed to 2500 rpm, the spatial three-dimensional metal skeleton 1 rotates, the mixed liquid stays in the device for 120s, and undergoes Fenton oxidation reaction under shear force to form countless tiny droplets.

[0094] (5) During the entire process, the first ultrasonic vibrator 3 and the second ultrasonic vibrator 4 generate alternating longitudinal waves with a frequency of 80kHz and a power of 800W. They operate intermittently at a frequency of 8h / time.

[0095] In this embodiment, the COD of the treated effluent is stable at 25–40 mg / L.

[0096] Example 3

[0097] This embodiment provides a wastewater treatment method, specifically treating wastewater after biochemical treatment of dyeing and printing wastewater. The original wastewater has a COD of 240-380 mg / L. The device provided in Embodiment 2 is used, with the only difference being that the catalytically active metal material in the metal ring is either iron oxide or manganese oxide.

[0098] Wastewater treatment methods include the following steps:

[0099] (1) Add concentrated sulfuric acid to adjust the pH of the wastewater to 5.5, and then let the wastewater flow into the inlet pipe through the wastewater inlet 12;

[0100] (2) Add solid ferrous sulfate to ferrous sulfate inlet 10 so that 160 mg of ferrous sulfate is added to each 1 L of wastewater, and add 30% hydrogen peroxide solution to hydrogen peroxide inlet 11 so that 180 mg of hydrogen peroxide is added to each 1 L of wastewater.

[0101] (3) The wastewater after adding ferrous sulfate and hydrogen peroxide enters the spatial three-dimensional metal skeleton 1 through the water distributor 5; wherein, the mixing time of the mixture formed by the wastewater and Fenton reagent in the macro mixer is 16s;

[0102] (4) Set the rotation speed to 1000 rpm, the spatial three-dimensional metal skeleton 1 rotates, and the mixed liquid stays in the device for 120s for catalytic oxidation to form countless tiny droplets;

[0103] (5) Throughout the process, the first ultrasonic vibrator 3 and the second ultrasonic vibrator 4 generate alternating longitudinal waves with a frequency of 100kHz and a power of 1000W. The ultrasonic vibrators can operate continuously.

[0104] In this embodiment, the COD of the treated effluent is stable at 30-40 mg / L.

[0105] Table 1 shows the COD removal rate of the spatial three-dimensional metal skeleton 1 at different rotation speeds under the same conditions as in Example 2, with a reaction time of 45 s in the device.

[0106] Table 1

[0107] Rotation speed 900rpm 1650rpm 2500rpm 3300rpm COD removal rate 70％～79％ 75％～82％ 84％～89％ 90％～95％

[0108] Table 2 shows the COD removal rate obtained by changing only the material of the metal ring compared to Example 2.

[0109] Table 2

[0110]

[0111] The heterogeneous Fenton oxidation reactor provided by this invention uses a metal ring material with catalytic properties, which can simultaneously disperse and catalyze the mixture, enhance the microscopic contact area between organic matter in wastewater and Fenton reagent, and ensure sufficient contact between the mixture and the metal ring, increasing the contact time of reactants. This can increase the rate of transfer and mixing reaction by 1 to 3 times, significantly shorten the material mixing and reaction time, reduce energy consumption, save reagent dosage, and effectively improve reagent utilization efficiency and catalyst catalytic efficiency.

[0112] 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 oxidation reaction apparatus, characterized by, The application relates to a heterogeneous Fenton oxidation reaction device. The heterogeneous Fenton oxidation reaction device comprises a space stereoscopic metal framework, a water distributor and an ultrasonic vibrator. The space stereoscopic metal framework is internally provided with a cavity, and comprises at least two metal rings provided with a plurality of holes penetrating through the metal rings. The metal rings are composed of single-element metal and / or metal oxide with catalytic action. The metal rings are concentrically arranged. The metal rings comprise at least one layer of metal net which encloses the metal ring. The metal net is composed of longitudinal and transverse metal wires. The metal wires are made of the single-element metal and / or the metal oxide. The water distributor is arranged in the cavity of the space stereoscopic metal framework.

2. The heterogeneous Fenton oxidation reaction apparatus according to claim 1, characterized by The heterogeneous Fenton oxidation reaction device further comprises an ultrasonic vibrator.

3. The heterogeneous Fenton oxidation reaction apparatus according to claim 2, wherein The ultrasonic vibrator is fixed to the outer wall of the space stereoscopic metal framework.

4. The heterogeneous Fenton oxidation reaction apparatus according to claim 1, wherein The heterogeneous Fenton oxidation reaction device further comprises a shell, and the space stereoscopic metal framework is arranged in the shell.

5. The heterogeneous Fenton oxidation reaction device according to claim 4, characterized in that, The thickness of the metal ring is 1 / 15-7 / 10 of the radius of the shell.

6. The heterogeneous Fenton oxidation reaction apparatus according to claim 4, wherein The single-element metal comprises at least one of iron, manganese, copper and nickel.

7. The heterogeneous Fenton oxidation reaction apparatus according to claim 1, wherein The metal oxide comprises at least one of iron oxide, manganese oxide, copper oxide and nickel oxide.

8. The heterogeneous Fenton oxidation reaction apparatus according to claim 7, wherein The metal wires are longitudinal and transverse.

9. The heterogeneous Fenton oxidation reaction apparatus according to claim 1, wherein The diameter of the metal wires is 1.2-4.0 mm.

10. The heterogeneous Fenton oxidation reaction apparatus according to claim 1, wherein The metal rings are arranged at equal intervals.

11. The heterogeneous Fenton oxidation reaction apparatus according to claim 1, wherein The shortest interval between adjacent metal rings is 1 / 5-1 / 3 of the radius of the cavity. The water distributor is provided with at least three openings for conveying the mixed solution in the water distributor to the space stereoscopic metal framework, so that the mixed solution is subjected to shearing force and Fenton oxidation reaction.

12. The heterogeneous Fenton oxidation reaction apparatus according to claim 11, wherein The water distributor is arranged in the axial direction of the space stereoscopic metal framework.

13. The heterogeneous Fenton oxidation reaction apparatus according to claim 2, wherein The heterogeneous Fenton oxidation reaction device further comprises a macroscopic mixer which is communicated with the water distributor. The macroscopic mixer comprises a pipe body and a plurality of fins which divide the conveying section of the pipe body. The fins are arranged at a predetermined angle.

14. The heterogeneous Fenton oxidation reaction apparatus according to any one of claims 1 to 13, characterized by, The fins are in the shape of a spiral, a circle or a square. The heterogeneous Fenton oxidation reaction device further comprises a rotating shaft which penetrates through the shell and the space stereoscopic metal framework and drives the space stereoscopic metal framework to rotate. The heterogeneous Fenton oxidation reaction device further comprises an electric motor which provides electric energy.

15. A method of wastewater treatment, characterized by, The heterogeneous Fenton oxidation reaction device further comprises a water inlet pipe which is communicated with the water distributor and is provided with a wastewater inlet and a Fenton reagent inlet. A wastewater outlet is arranged at the bottom of the shell.

16. The wastewater treatment method according to claim 15, characterized by, The heterogeneous Fenton oxidation reaction device is used to perform the following steps.

17. The wastewater treatment method of claim 16, wherein, The pH-adjusted wastewater is mixed with Fenton reagent to obtain a mixed solution, and the mixed solution is conveyed to the heterogeneous Fenton oxidation reaction device to perform Fenton oxidation reaction.

18. The wastewater treatment method of claim 16, wherein, The Fenton reagent comprises FeSO4 and H2O2.

19. The wastewater treatment method of claim 15, wherein, The dosage of the FeSO4 is 150-250 mg / L.

20. The wastewater treatment method of claim 19, wherein, The dosage of the H2O2 is 100-200 mg / L. The Fenton oxidation reaction time of the mixed solution is 30-120 s. The pH value of the pH-adjusted wastewater is 5.0-5.

5.

21. The wastewater treatment method of claim 15, wherein, The method further comprises the step of controlling the frequency of the ultrasonic vibrator to be 40-80 kHz and the power to be 30-1500 W during the Fenton oxidation reaction.

22. The wastewater treatment method according to claim 21, wherein, The ultrasonic vibrator is operated in an intermittent mode or a continuous mode.

23. The wastewater treatment method of claim 22, wherein, The frequency of the intermittent operation of the ultrasonic vibrator is 6 h / time to 12 h / time.

24. The wastewater treatment method of claim 22, wherein, The rotating speed of the spatial three-dimensional metal skeleton is 800 rpm to 3500 rpm.

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