Rotary heterogeneous fenton oxidation reaction device and wastewater treatment method

Abstract

The present application relates to wastewater treatment technical field, specifically to a kind of rotating heterogeneous fenton oxidation reaction device and wastewater treatment method, the device includes space three-dimensional metal framework and water distributor, space three-dimensional metal framework inside is equipped with cavity, at least including 1 metal ring, metal ring includes 2 metal sheets and catalyst filled between 2 metal sheets;Each metal sheet is equipped with several holes that pass through the metal sheet;Water outlet of water distributor is set in the cavity inside space three-dimensional metal framework.This device can strengthen the micro-contact area of organic matter in wastewater and fenton reagent, and make mixed solution and catalyst fully contact, increase the contact time of reactants, can increase the rate of heterogeneous fenton reaction transmission and mixing reaction process by 1-3 times, can greatly shorten the mixing reaction time, also can improve the utilization efficiency of catalyst, to reduce the amount of chemical reagent used, while the equipment cost is less, energy consumption is low, and the floor space is also small.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, in particular to a rotating heterogeneous Fenton oxidation reaction device and a wastewater treatment method. BACKGROUND

[0002] Chemical, food, smelting, electroplating, textile printing and dyeing, mining, papermaking, leather, pharmaceutical, petroleum and other industries will produce a large amount of wastewater and waste liquid, i.e. industrial wastewater, which mainly contains industrial production materials, intermediate products and pollutants generated during the production process. Because of its complex types and numerous components, most of which are difficult to degrade and have certain toxicity, it is difficult to achieve a suitable balance between treatment and cost control, and it is recognized as a major problem in the field.

[0003] At present, the treatment method for high-concentration industrial wastewater is advanced oxidation technology, which uses active substances to oxidize, decompose and mineralize most of the organic matter in wastewater, achieving efficient removal of refractory organic matter, among which activated carbon adsorption, ozone oxidation and Fenton oxidation process are mainly used. However, the activated carbon adsorption method requires a large amount of activated carbon, has high recycling and regeneration costs, and can easily affect the factory environment. Ozone oxidation has a certain selectivity for pollutants and is difficult to completely decompose refractory organic matter, and the oxidation products are often small molecular carboxylic acids, ketones and aldehydes. For example, CN114262117A discloses a system for deep degradation of COD in organic wastewater, which includes a raw water pool, an oxygen cylinder, an ozone generating device, a rotating packed bed (RPB) reactor, an intermediate conditioning pool, an air pump, a liquid storage pool and a sequencing batch reactor (SBR). The patent belongs to gas-liquid two-phase mixing, and the ozone oxidation process has selectivity and can only treat part of the organic matter. For some organic matter that is difficult to oxidize, such as benzene and toluene, the treatment effect is not ideal. The principle of Fenton oxidation reaction is to generate strong oxidizing hydroxyl radicals (·OH) through Fe 2+ and H2O2 under acidic conditions to achieve the purpose of degrading organic pollutants, which has the advantages of simple operation, wide application of pollution types and low risk of secondary pollution, and is a promising technology for treating refractory organic pollutants.

[0004] Fenton oxidation reaction includes homogeneous Fenton oxidation reaction and heterogeneous Fenton oxidation reaction. The pH application range of homogeneous Fenton oxidation reaction is narrow, and the organic matter cannot be fully mineralized. The utilization rate of H2O2 is low, and a large amount of iron sludge is generated during the treatment process, which increases the cost. In comparison, heterogeneous Fenton oxidation reaction is a typical catalytic oxidation reaction occurring on the interface between liquid and solid phases. The principle is that the metal cations on the surface of the solid catalyst react with H2O2 to generate strong oxidizing ·OH. ·OH degrades organic pollutants through three ways: electrophilic addition to double bonds or aromatic rings, hydrogen abstraction from alkyl or hydroxyl groups, and electron transfer reactions. The utilization rate of hydrogen peroxide is high, and a large amount of iron sludge is not generated. The pH application range is wider, and the cost is lower. It is the research hotspot in the field of wastewater treatment at present.

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

[0006] The existing technology mainly improves the performance of the catalyst itself to improve the removal effect of pollutants. For example, Chinese patent applications CN115869950A, CN115814796A, CN113856680A and CN110465300A all start from the catalyst itself, develop solid catalysts with large specific surface area, increase the liquid-solid contact area, and thus improve the removal efficiency of refractory pollutants. However, the solid catalyst with large specific surface area has the disadvantage of high density, which sinks quickly in liquid and has poor fluidization effect.

[0007] In addition to optimizing the performance of the catalyst itself, by optimizing the macro-mixing process, increasing the contact area of the catalyst with the reaction system, and strengthening the reaction process, higher catalytic oxidation efficiency can also be achieved. The conventional technical means for optimizing the macro-mixing process is mainly through optimizing the reactor configuration or using mechanical stirring, increasing reflux or increasing aeration, etc., by increasing the liquid disturbance to improve the contact degree with the solid catalyst. For example, CN107640854A discloses "a deep treatment integrated method for printing and dyeing wastewater with oxidation time in seconds", CN107473453A discloses "a new type of pure fluid static pipeline reactor", etc., which uses water jet, static mixer, etc. as the mixing method of the reagent to realize extremely short catalytic oxidation reaction, saving the space and cost of tower construction. But this type of reactor has the following problems: (1) it is still a homogeneous Fenton oxidation reaction in nature, with narrow pH range, large reagent consumption and low catalytic efficiency; (2) in actual million-ton wastewater treatment plants, the length and land area required by the mixing pipeline due to residence time are large, and the site requirement is high; (3) the resistance loss of the long mixing pipeline and the elbow is large, and in many cases, an additional water inlet pump or booster pump needs to be set to ensure that the wastewater can flow in and out smoothly, increasing the energy consumption of the whole reaction process.

[0008] In actual operation, there are still dead zones and short flow phenomena in the reactor of the macro-mixing process, and the optimization of the macro-mixing process is rough and the fluidization effect is not good, which also leads to low utilization rate of solid catalyst, large reagent dosage. At the same time, in the traditional heterogeneous catalytic reaction process, the catalyst is easy to appear hardening and passivation phenomenon, leading to catalyst deactivation and waste, affecting the catalytic efficiency.

[0009] In summary, the macro-mixing process and the heterogeneous Fenton oxidation reactor have the problems of long reaction time, large size, large land area, poor fluidization effect, and serious hardening and deactivation phenomenon. And the problems of high energy consumption caused by secondary lifting and mechanical and aeration mixing methods, etc., are not environmentally friendly. SUMMARY

[0010] Therefore, the technical problem to be solved by the present application is to overcome the defects in the prior art that the equipment for treating wastewater by using heterogeneous Fenton reaction has large land area, high energy consumption, large reagent dosage, low utilization rate of solid catalyst, and easy hardening and passivation phenomenon, thereby providing a rotary heterogeneous Fenton oxidation reaction device and a wastewater treatment method.

[0011] To this end, the present application provides the following technical solutions:

[0012] The application provides a rotating heterogeneous Fenton oxidation reaction device, which comprises a space stereoscopic metal framework, a cavity is arranged in the space stereoscopic metal framework, and the space stereoscopic metal framework comprises at least one metal ring, for example, one, two, three, four, five or any number of metal rings, and the number is not limited, and preferably three to seven; the metal ring comprises two metal sheets and a solid catalyst filled between the two metal sheets; each metal sheet is provided with a plurality of holes penetrating through the metal sheet; and a water distributor, wherein the water outlet of the water distributor is arranged in the cavity in the space stereoscopic metal framework.

[0013] Preferably, the device further comprises a macro-mixer in communication with the water distributor; preferably, the macro-mixer comprises a pipe body and a plurality of fins, the fins divide the liquid transported in the pipe body, the plurality of fins are arranged along the extension direction of the pipe body, and adjacent two fins are arranged at a predetermined angle; preferably, the fins are in the shape of a spiral, a circle or a square. Specifically, the material of the fins comprises stainless steel 316L, and the predetermined angle between adjacent two fins can be, but is not limited to, 90°, 120° or 135°; the pipe diameter of the macro-mixer is 0.1-1.2 m.

[0014] Optionally, the spacing between adjacent metal rings in the space stereoscopic framework can be arranged at equal intervals or non-equal intervals, which can be adjusted according to actual needs.

[0015] Preferably, the plurality of metal rings in the space stereoscopic metal framework are arranged concentrically.

[0016] Preferably, the plurality of metal rings in the space stereoscopic metal framework are arranged at equal intervals.

[0017] Preferably, the shortest spacing between adjacent metal rings is 1 / 5-1 / 3 of the radius of the cavity.

[0018] Preferably, the metal sheet comprises at least one layer of metal mesh; preferably, the metal mesh is composed of longitudinally and transversely intersecting metal wires; the apertures formed by the longitudinally and transversely intersecting metal wires are the holes penetrating through the metal sheet; the diameter of the metal wire is 1.2-4.0 mm; and the metal wire is acid and alkali corrosion resistant, and comprises one or more of stainless steel, magnesium-aluminum alloy, brass and carbon steel.

[0019] Preferably, the rotating heterogeneous Fenton oxidation reaction device further comprises a shell, and the space stereoscopic metal framework is arranged in the shell.

[0020] Preferably, the thickness of the metal ring is 1 / 15-7 / 10 of the radius of the shell.

[0021] Preferably, the thickness of the metal sheet is 2-5 mm.

[0022] Preferably, the solid catalyst is an iron-based catalyst.

[0023] Preferably, the solid catalyst is spherical.

[0024] Preferably, the diameter of the solid catalyst is 2-3 mm.

[0025] Preferably, the diameter of the solid catalyst is greater than the size of the hole of the metal sheet.

[0026] Preferably, the filling volume ratio of the solid catalyst in the metal ring is any value between 50% and 85%, for example, but not limited to, 55%, 60%, 70%, 75%, 80%, etc.

[0027] Preferably, the water distributor is provided with at least 3 openings for delivering the mixed solution in the water distributor to the spatial three-dimensional metal framework. The shape of the openings can be, but is not limited to, circular, rectangular, etc. Preferably, the water distributor is provided with 3-9 openings.

[0028] Preferably, the water distributor is arranged in the axial direction of the spatial three-dimensional metal framework.

[0029] Preferably, the rotating heterogeneous Fenton oxidation reaction device further comprises at least 1 ultrasonic vibrator. Further, in the device, the number of ultrasonic vibrators can be, but is not limited to, 1, 2, 3, 4, etc.

[0030] Preferably, the ultrasonic vibrator is fixed to the outer wall of the spatial three-dimensional metal framework. When there are 2 ultrasonic vibrators, they can be symmetrically arranged on the outer wall of the device.

[0031] Preferably, the rotating heterogeneous Fenton oxidation reaction device further comprises a rotating shaft penetrating through the shell and connected with the spatial three-dimensional metal framework, for driving the spatial three-dimensional metal framework to rotate, so that the wastewater inside the cavity is in full contact and shearing with the metal mesh under the action of centrifugal force, forming micro-droplets; and a motor, for providing electric energy.

[0032] Preferably, the rotating heterogeneous Fenton oxidation reaction device further comprises a water inlet pipe in communication with the water distributor; the water inlet pipe is provided with a wastewater inlet and a Fenton reagent inlet; and a wastewater outlet, arranged at the bottom of the shell.

[0033] The application also provides a wastewater treatment method, which adopts the above-mentioned rotating heterogeneous Fenton oxidation reaction device, and comprises the following steps: mixing the wastewater after pH adjustment with Fenton reagent, and delivering the mixed solution to the rotating heterogeneous Fenton oxidation reaction device for Fenton oxidation reaction.

[0034] Preferably, the Fenton reagent comprises FeSO4 and H2O2.

[0035] Preferably, the dosage of FeSO4 is 150-250 mg / L.

[0036] Preferably, the dosage of H2O2 is 100-200 mg / L.

[0037] Preferably, the mixing time of wastewater and Fenton reagent is 3-10 s; the mixing time refers to the mixing time of wastewater and Fenton reagent in a macro-mixer.

[0038] The time of Fenton oxidation reaction is 30-120 s; the reaction time refers to the reaction time of the mixed liquid in the rotating heterogeneous Fenton oxidation reaction device.

[0039] Preferably, the pH value of wastewater after pH adjustment is 5.0-5.5.

[0040] Preferably, the frequency of ultrasonic vibrator is 40-80 kHz, and the power is 30-1500 W.

[0041] Preferably, the ultrasonic vibrator is operated in an intermittent or continuous mode.

[0042] Preferably, the frequency of intermittent operation of ultrasonic vibrator is 6 h / time-12 h / time.

[0043] Preferably, the rotating speed of spatial three-dimensional metal framework is 800-3000 rpm.

[0044] The technical scheme of the present application has the following advantages:

[0045] 1. In terms of micro-mixing reaction, the rotating heterogeneous Fenton oxidation reaction device provided by the present application comprises a spatial three-dimensional metal framework and a water distributor, the spatial three-dimensional metal framework is internally provided with a cavity, the spatial three-dimensional metal framework comprises at least one metal ring, the metal ring comprises two metal sheets and a solid catalyst filled between the two metal sheets, each metal sheet is provided with a plurality of holes penetrating through the metal sheet, and the water outlet of the water distributor is arranged in the cavity inside the spatial three-dimensional metal framework. The rotating heterogeneous Fenton oxidation reaction device can strengthen the micro-contact area of organic matters in wastewater and Fenton reagent, make the mixed liquid and the catalyst fully contact, increase the contact time of reactants, increase the rate of heterogeneous Fenton reaction transmission and mixing reaction process by 1-3 times, greatly shorten the mixing reaction time, improve the utilization efficiency of catalyst, thereby reducing the amount of chemical reagents used, and the device has the advantages of low capital cost, low energy consumption, small occupied space, etc.

[0046] The spatial stereoscopic metal framework comprises at least one metal ring, the metal ring comprises two metal sheets and a solid catalyst filled between the two metal sheets, and a plurality of holes penetrating through the metal sheets are arranged on each metal sheet, and the holes form a channel through which a mixed solution can pass. With rotation of the spatial stereoscopic metal framework, the mixed solution is highly sheared, dispersed and broken into fine droplets when passing through the holes on the metal sheets, the formed droplets can be as small as molecular scale, the specific surface area of the liquid is increased, and the innumerable tiny droplets are dispersed to any position of the spatial stereoscopic metal framework and fully contact and react with the filled catalyst, the interfacial mass transfer effect between the tiny fluid units and the catalyst is improved due to the great turbulent disturbance, and then the heterogeneous catalytic micro-mixing reaction process is enhanced, the rate of the heterogeneous Fenton reaction transmission and mixing reaction process is increased by 1-3 times, the removal efficiency of the refractory organic pollutants is increased, and then the reagent dosage and the subsequent iron sludge yield can be reduced, meanwhile, the device has the advantages of low capital cost, low energy consumption and small occupied space.

[0047] 2. In the aspect of macro-mixing reaction, the rotating heterogeneous Fenton oxidation reaction device also comprises a macro-mixer in communication with the water distributor, wherein the wastewater and the Fenton reagent are fully mixed by the macro-mixer and then introduced into the water distributor. The macro-mixer comprises a pipe body and a plurality of fins, the fins cut the liquid conveyed in the pipe body, the fins are arranged along the extension direction of the pipe body, and adjacent two fins are arranged at a predetermined angle. Preferably, the fins are in the shape of a spiral, a circle or a square. Specifically, the material of the fins comprises stainless steel 316L, the predetermined angle between adjacent two fins can be but is not limited to 90°, 120° or 135°, and the pipe diameter of the macro-mixer is 0.1-1.2 m. The mixed solution generates rotational turbulence, vortex and counter-vortex in the macro-mixer, thereby promoting the macro and efficient mixing of the Fenton reagent and the wastewater.

[0048] 3. The ultrasonic waves generated by the ultrasonic vibrator are longitudinal waves between dense and sparse phases, the cavitation effect of the ultrasonic waves generates a strong perturbation effect on the surface of the metal ring, and then the dirt layer on the surface of the metal ring with catalytic activity is dispersed, emulsified and peeled off, so that the catalyst is cleaned and the phenomenon of serious catalyst caking and deactivation in the traditional heterogeneous Fenton oxidation reaction process is solved.

[0049] The mechanical effect and chemical effect generated by the cavitation effect of the ultrasonic waves improve the mass transfer and mixing efficiency in the reactor, strengthen the generation process of the active oxygen species, accelerate the reaction rate, solve the problems of catalyst blockage and scaling caused by the iron sludge generated by the reaction of FeSO4 and hydrogen peroxide, effectively slow down the caking phenomenon of the catalytically active element, and have the self-cleaning ability.

[0050] 4. A plurality of metal rings can be concentrically arranged in the spatial stereoscopic metal framework, so that the mass of the device is reduced, and the energy consumption is further reduced.

[0051] The metal sheet for composing the metal ring comprises at least one metal net composed of metal wires crisscrossing each other, the formed aperture is a hole penetrating through the metal sheet, and the material of the metal wire comprises one or more of stainless steel, magnesium-aluminum alloy, brass and carbon steel, and is acid and alkali corrosion resistant.

[0052] The metal ring is filled with a solid catalyst, specifically, an iron-based catalyst with Fe3O4 as the main component, an iron-manganese-based catalyst with Fe3O4 / MnO2 as the main component, and an iron-manganese-nickel-based catalyst with Mn3O4-Ni / C@FeOOH as the main component, which are all suitable for the application; can efficiently catalyze heterogeneous Fenton oxidation reaction, and reduce the dosage of FeSO4 reagent.

[0053] 5. The wastewater treatment method provided by the application can improve the wastewater treatment efficiency, improve the catalytic efficiency and reaction efficiency, and greatly reduce the dosage of reagents by using the device of the application and strengthening the macroscopic and microscopic mixing reaction process, and is suitable for a system with pH of 5.0-5.5, and widens the pH value application range of the traditional Fenton oxidation reaction for treating wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0055] Figure 1 It is a schematic diagram of the rotating heterogeneous Fenton oxidation reaction device of the application;

[0056] Figure 2 It is a schematic diagram of the internal structure of the macroscopic mixer of the application;

[0057] Figure 3 It is a schematic diagram of the spatial three-dimensional metal framework of the application, wherein 3a is a cross-sectional view of the spatial three-dimensional metal framework comprising a plurality of metal rings, and 3b is a cross-sectional view of the spatial three-dimensional metal framework comprising one metal ring;

[0058] Figure 4 It is a schematic diagram of the appearance of the metal net of the application;

[0059] Figure 5 It is a schematic diagram of the hole shape of the water distributor of the application.

[0060] Explanation of reference signs:

[0061] 1 - spatial stereoscopic metal skeleton; 2 - macro-mixer; 3 - first ultrasonic vibrator; 4 - second ultrasonic vibrator; 5 - water distributor; 6 - rotating shaft; 7 - motor; 8 - shell; 9 - wastewater outlet; 10 - ferrous sulfate inlet; 11 - hydrogen peroxide inlet; 12 - wastewater inlet. DETAILED DESCRIPTION

[0062] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0063] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0064] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0065] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0066] Example 1

[0067] The present embodiment provides a device for treating wastewater by rotating heterogeneous Fenton oxidation reaction, as shown in Figure 1 , comprising:

[0068] The spatial three-dimensional metal framework 1 is internally provided with a cavity, and the spatial three-dimensional metal framework 1 at least comprises one metal ring, the metal ring comprises two metal sheets and a solid catalyst filled between the two metal sheets, each metal sheet is provided with a plurality of holes penetrating through the metal sheet; specifically, the thickness of the metal sheet is any value within the range of 2mm to 5mm, the metal sheet is made of acid and alkali corrosion resistant material, and specifically comprises one or more of stainless steel, aluminum magnesium alloy, brass and carbon steel; the spatial three-dimensional metal framework can comprise one, two, three, four, five or any number of metal rings, and the number thereof is not specifically limited, and preferably 3 to 7; the number of holes on the metal sheet is not specifically limited; the solid catalyst is an iron-based catalyst, and specifically can be an iron-based catalyst with Fe3O4 as the main component, an iron-manganese-based catalyst with Fe3O4 / MnO2 as the main component, an iron-manganese-nickel-based catalyst with Mn3O4-Ni / C@FeOOH as the main component, etc. The catalyst is spherical with a diameter of 2 to 3mm, which is larger than the size of the metal sheet hole, so as to prevent the catalyst from separating from the metal ring hole during high-speed rotation, and the filling volume ratio in the metal ring is any value within the range of 50% to 85%, for example, the filling volume ratio can be but is not limited to 55%, 60%, 70%, 75%, 80%, etc.

[0069] The water distributor 5 is provided with an outlet inside the cavity.

[0070] The spatial three-dimensional metal framework 1 rotates, under the action of centrifugal force, the mixed solution is discharged from the outlet of the water distributor 5 into the spatial three-dimensional metal framework 1 and is subjected to shearing force, and further shearing effect is achieved due to the holes provided on the metal sheet, the mixed solution is broken into small droplets, the specific surface area is increased, the mass transfer process is strengthened by the huge turbulent disturbance, the mixed solution is highly sheared and dispersed, and reaches each position of the spatial three-dimensional metal framework 1 through the holes to fully contact with the solid catalyst, the mass transfer effect is improved, the catalysis and reaction efficiency are improved, the removal rate of refractory organic pollutants is effectively improved, the reaction time is shortened, the reagent dosage is reduced, and the subsequent iron sludge production is reduced.

[0071] As a preferred embodiment, a macro-mixer 2 is further included, which is in communication with the water distributor 5; as shown in Figure 2 The macro-mixer 2 comprises a pipe body and a plurality of fins, the fins cut the liquid conveyed in the pipe body, the fins are arranged along the extension direction of the pipe body, and adjacent two fins are arranged at a predetermined angle; preferably, the fins are in spiral, circular or square shape. Specifically, the material of the fins comprises stainless steel 316L, and the predetermined angle between adjacent two fins can be but is not limited to 90°, 120°, 135°; the pipe diameter of the macro-mixer is 0.1 to 1.2m. The mixed solution generates rotational turbulent flow, vortex and counter vortex in the macro-mixer 2, promoting the macro and efficient mixing of Fenton reagent and wastewater.

[0072] As a preferred embodiment, when the spatial stereoscopic metal framework 1 comprises a plurality of metal rings, the plurality of metal rings in the spatial stereoscopic metal framework 1 are concentric ring structures, as shown in Figure 3 a is a cross-sectional view of the spatial stereoscopic metal framework 1 comprising a plurality of metal rings, Figure 3 b is a cross-sectional view of the spatial stereoscopic metal framework 1 comprising one metal ring. The spacing between adjacent metal rings can be arranged at equal intervals or non-equal intervals, which can be adjusted according to actual needs. Preferably, the shortest spacing between adjacent metal rings is 1 / 5 to 1 / 3 of the radius of the internal cavity of the spatial stereoscopic metal framework. Further, the internal space of the metal ring with the smallest corresponding size of the cavity, i.e., the cavity radius corresponds to the inner diameter of the smallest metal ring.

[0073] As a preferred embodiment, the metal sheet can be a one-layer sheet structure with holes or the metal sheet can further comprise at least one metal mesh, and the two metal sheets enclose to form a metal ring, and the metal mesh is composed of a plurality of longitudinal and transverse intersecting metal wires, as shown in Figure 4 As shown, there are pores between the longitudinal and transverse intersecting metal wires, and these pores are holes penetrating through the metal sheet. Further, the cross-sectional shape of the metal wire is polygonal or circular, and the polygonal shape can be but is not limited to triangular, quadrangular, pentagonal, etc. When the cross-sectional shape of the metal wire is polygonal, the metal wire can further strengthen the shearing effect due to the edges and corners of the metal wire. The metal ring has high mechanical strength and can shorten the reaction time and reduce the subsequent iron sludge yield while considering the efficient shearing and mixing functions. Further, when the cross-sectional shape of the metal wire is circular, the diameter of the metal wire is 1.2 to 4.0 mm.

[0074] As a preferred embodiment, it further comprises:

[0075] The shell 8 sets the spatial stereoscopic metal framework 1 inside the shell 8; the thickness of the metal ring is 1 / 15 to 7 / 10 of the radius of the shell 8.

[0076] As a preferred embodiment, the water distributor 5 is provided with at least three openings for transporting the mixed solution in the water distributor 5 to the spatial stereoscopic metal framework 1, and the mixed solution is subjected to shearing and Fenton oxidation reaction. Further, the water distributor 5 is arranged in the axial direction of the spatial stereoscopic metal framework 1. The shape of the opening can be but is not limited to circular, rectangular, etc., as shown in Figure 5 Preferably, the water distributor 5 is provided with 3 to 9 openings.

[0077] As a preferred embodiment, at least one ultrasonic vibrator is further included and fixed to the outer wall of the spatial three-dimensional metal framework 1; further, in the device, the number of ultrasonic vibrators can be, but is not limited to, 1, 2, 3, 4, etc.; when there are two ultrasonic vibrators, they can be symmetrically arranged on the outer wall of the device. Through the cavitation effect of ultrasonic waves, a strong perturbation effect is generated on the surface of the metal ring, and then the dirt layer on the surface of the metal ring with catalytic activity is dispersed, emulsified and peeled off, thereby achieving the purpose of cleaning the solid catalyst, and solving the problems of serious catalyst hardening and deactivation, blockage caused by iron mud and structure in the traditional heterogeneous Fenton oxidation reaction process, and having a self-cleaning effect.

[0078] As a preferred embodiment, the device further comprises:

[0079] The rotating shaft 6 penetrates the shell 8 and is connected with the spatial three-dimensional metal framework 1 to drive the spatial three-dimensional metal framework 1 to rotate;

[0080] The motor 7 provides electric energy to drive the spatial three-dimensional metal framework 1 to rotate;

[0081] The water inlet pipe is in communication with the water distributor 5; the water inlet pipe is provided with a wastewater inlet 12 and a Fenton reagent inlet; specifically, the water inlet pipe is provided with a wastewater inlet 12, a ferrous sulfate inlet 10 and a hydrogen peroxide inlet 11;

[0082] The wastewater outlet 9 is arranged at the bottom of the shell 8.

[0083] The device provided in the embodiment can strengthen the micro contact area of organic matter in wastewater with Fenton reagent, increase the contact time of reactants, has good fluidization effect, can increase the rate of transmission and mixing reaction process by 1-3 times, greatly shorten the material mixing and reaction time, reduce energy consumption, save the dosage of reagent, improve the utilization efficiency of reagent, and improve the catalytic efficiency of catalyst. The device also has the advantages of small occupied space, no aeration and high energy consumption problems such as secondary lifting.

[0084] Further, the device provided by the present application can be used for pretreatment before biochemical treatment, and can also be applied to advanced treatment after biochemical treatment of refractory organic wastewater.

[0085] Embodiment 2

[0086] The embodiment provides a method for treating wastewater by heterogeneous Fenton oxidation reaction, and a wastewater after biochemical treatment of petroleum chemical wastewater is treated by using the device in embodiment 1; the COD of the original wastewater is 300 mg / L; the device comprises:

[0087] The spatial three-dimensional metal framework 1 is internally provided with a cavity, and comprises five concentric metal rings, each of which comprises two metal sheets and a solid catalyst filled between the two metal sheets, and the thickness of the metal ring is 1 / 5 of the radius of the shell; the spacing between adjacent metal rings is arranged at equal intervals, and the shortest spacing is 1 / 5 of the radius of the cavity inside the spatial three-dimensional metal framework; the metal sheet is 5 mm thick, made of stainless steel, and has a one-layer metal mesh structure composed of longitudinal and transverse intersecting metal wires, and there are apertures between the longitudinal and transverse intersecting metal wires, which are through holes in the metal sheet, the cross-sectional shape of the metal wire is circular, the diameter is 2.0 mm, the two metal sheets enclose a metal ring, and the two metal sheets are filled with an iron-based catalyst (manufactured by Shandong Jieyao Science and Technology Development Co., Ltd.) with a spherical shape and a diameter of 3 mm, and the filling volume in the metal ring accounts for 30%.

[0088] The water distributor 5 is provided with three openings, so that the mixed solution enters the spatial three-dimensional metal framework 1 in the form of a liquid column.

[0089] The macro-mixer 2 is in communication with the water distributor 5 and comprises a pipe body and a plurality of fins, the fins divide the conveying section of the pipe body, the plurality of fins are arranged along the extension direction of the pipe body, and adjacent two fins are arranged at a predetermined included angle of 90°, the fin is made of stainless steel 316L and has a semicircular arc shape.

[0090] The two ultrasonic vibrators, the first ultrasonic vibrator 3 and the second ultrasonic vibrator 4, are symmetrically fixed to the outer wall of the spatial three-dimensional metal framework 1.

[0091] The shell 8 is internally provided with the spatial three-dimensional metal framework 1.

[0092] The rotating shaft 6 penetrates the shell 8 and is connected with the spatial three-dimensional metal framework 1 to drive the spatial three-dimensional metal framework 1 to rotate.

[0093] The motor 7 provides electric energy to drive the spatial three-dimensional metal framework 1 to rotate.

[0094] The water inlet pipe is in communication with the water distributor 5, and the water inlet pipe is provided with a wastewater inlet 12, a ferrous sulfate inlet 10 and a hydrogen peroxide inlet 11.

[0095] The wastewater outlet 9 is arranged at the bottom of the shell 8.

[0096] The wastewater treatment method comprises the following steps:

[0097] (1) adding concentrated sulfuric acid to adjust the pH of the wastewater to 5.1, and then introducing the wastewater into the water inlet pipe through the wastewater inlet 12;

[0098] (2) FeSO4 solid is added at FeSO4 inlet 10, 180 mg FeSO4 per 1 L wastewater is added, and 30% H2O2 solution is added at H2O2 inlet 11, 200 mg H2O2 per 1 L wastewater is added, about 666.67 mg H2O2 solution;

[0099] (3) The wastewater after adding FeSO4 and H2O2 enters the space stereoscopic metal framework 1 through the water distributor 5; wherein the mixing time of the wastewater and the Fenton reagent in the macro-mixer is 5 s;

[0100] (4) The space stereoscopic metal framework 1 rotates at a speed of 2500 rpm, the mixed liquid stays in the device for 30 s, and the Fenton oxidation reaction is carried out under the action of shear force to form countless micro-droplets;

[0101] (5) In the whole treatment process, the first ultrasonic vibrator 3 and the second ultrasonic vibrator 4 generate longitudinal waves between the dense and sparse phases, the frequency is 50 kHz, and the power is 800 W. Intermittent operation can be used, and the operation frequency is 8 h / time;

[0102] In this embodiment, the COD of the treated effluent is stabilized at 30-45 mg / L.

[0103] Example 3

[0104] The wastewater treatment method provided in this embodiment is specifically for treating the wastewater before biochemical treatment of printing and dyeing wastewater, the COD of the original wastewater is 250-300 mg / L, and the device provided in Example 2 is used, the only difference is that the space stereoscopic metal framework 1 only includes one metal ring, as shown in Figure 3 b.

[0105] The wastewater treatment method includes the following steps:

[0106] (1) Concentrated sulfuric acid is added to adjust the pH of the wastewater to 5.5, and then the wastewater is introduced into the water inlet pipe through the wastewater inlet 12;

[0107] (2) FeSO4 solid is added at FeSO4 inlet 10, 180 mg FeSO4 per 1 L wastewater is added, and 30% H2O2 solution is added at H2O2 inlet 11, 200 mg H2O2 per 1 L wastewater is added;

[0108] (3) The wastewater after adding FeSO4 and H2O2 enters the space stereoscopic metal framework 1 through the water distributor 5; wherein the mixing time of the wastewater and the Fenton reagent in the macro-mixer is 10 s;

[0109] (4) Set the rotating speed to 1000 rpm, the space stereoscopic metal framework 1 rotates, the mixed liquid stays in the device for 120 s for catalytic oxidation to form numerous micro-droplets;

[0110] (5) During the whole treatment process, the first ultrasonic vibrator 3 and the second ultrasonic vibrator 4 generate longitudinal waves between dense and sparse phases, the frequency is 100 kHz, and the power is 1000 W. The continuous operation mode is adopted;

[0111] In the embodiment, the COD of the treated effluent is stabilized at 40-50 mg / L.

[0112] Test results

[0113] Table 1 is the COD removal rate under different rotating speeds of the space stereoscopic metal framework under the same conditions as those of Example 2, and the reaction time in the device is 45 s.

[0114] Table 1

[0115] Rotational speed 900 rpm 1650 rpm 2500 rpm 3000 rpm COD removal rate 72％～76％ 75％～81％ 80％～84％ 85％～88％

[0116] The rotating heterogeneous Fenton oxidation reaction device provided by the application comprises a space stereoscopic metal framework and a water distributor, and the space stereoscopic metal framework comprises a metal sheet, and a plurality of holes penetrating through the metal sheet are arranged on the metal sheet. The device can strengthen the macroscopic and microscopic contact area of organic matter in wastewater and Fenton reagent, make the mixed liquid and the catalyst fully contact, increase the contact time of the reactants, improve the utilization efficiency of the catalyst, and thus reduce the amount of chemical reagents used. The heterogeneous Fenton catalytic oxidation process is carried out by using the rotating heterogeneous Fenton oxidation reaction device provided by the application, and the reaction is rapid, efficient and non-selective, and the rapid mineralization of organic matter can be realized in a short time (30-120 s).

[0117] Obviously, the above embodiments are only examples for clearly illustrating the application, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments need not and cannot be exhausted. The changes or variations derived therefrom are still within the protection scope of the application.

Claims

1. A rotary heterogeneous Fenton oxidation reactor, characterized in that, include: shell; A spatial three-dimensional metal skeleton is disposed inside the outer shell. The spatial three-dimensional metal skeleton has a cavity inside. The spatial three-dimensional metal skeleton includes at least three concentric and equally spaced metal rings. Each metal ring includes two metal sheets and a solid catalyst filled between the two metal sheets. Each metal sheet has a plurality of holes penetrating the metal sheet. The metal sheet includes at least one layer of metal mesh; The metal mesh is composed of crisscrossing metal wires; The crisscrossing metal wires form pores that penetrate the metal sheet; The diameter of the metal wire is 1.2~4.0 mm; The water distributor is located in the axial direction of the three-dimensional metal frame in the space; The water distributor's outlet is located in a cavity inside the spatial three-dimensional metal frame, and the water distributor has at least three openings for conveying the mixed liquid inside the water distributor to the spatial three-dimensional metal frame. It also includes a macro mixer, which is connected to the water distributor; It includes at least one ultrasonic vibrator, fixed to the outer wall of the spatial three-dimensional metal frame, with a frequency of 40 to 80 kHz; and a rotating shaft, which passes through the outer shell and is connected to the spatial three-dimensional metal frame, for driving the spatial three-dimensional metal frame to rotate. Electric motors provide electrical energy; The rotation speed of the spatial three-dimensional metal frame is 800~3000rpm.

2. The rotary heterogeneous Fenton oxidation reactor according to claim 1, characterized in that, The macro mixer includes a tube and several fins. The fins divide the liquid transported in the tube. The several fins are arranged along the extension direction of the tube, and adjacent fins are arranged at a predetermined angle.

3. The rotary heterogeneous Fenton oxidation reactor according to claim 2, characterized in that, The fins are spiral, circular, or square in shape.

4. The rotary heterogeneous Fenton oxidation reactor according to claim 1, characterized in that, The shortest distance between adjacent metal rings is 1 / 5 to 1 / 3 of the radius of the cavity.

5. The rotary heterogeneous Fenton oxidation reactor according to claim 1, characterized in that, The material of the metal wire includes one or more of stainless steel, magnesium-aluminum alloy, brass, and carbon steel.

6. The rotary heterogeneous Fenton oxidation reactor according to claim 1, characterized in that, The thickness of the metal ring is 1 / 15 to 7 / 10 of the radius of the outer shell.

7. The rotary heterogeneous Fenton oxidation reactor according to claim 1, characterized in that, The thickness of the metal sheet is 2mm to 5mm.

8. The rotary heterogeneous Fenton oxidation reactor according to claim 1, characterized in that, The solid catalyst is an iron-based catalyst.

9. The rotary heterogeneous Fenton oxidation reactor according to claim 8, characterized in that, The solid catalyst is spherical.

10. The rotary heterogeneous Fenton oxidation reactor according to claim 8, characterized in that, The diameter of the solid catalyst is 2-3 mm.

11. The rotary heterogeneous Fenton oxidation reactor according to claim 8, characterized in that, The diameter of the solid catalyst is larger than the size of the pores in the metal sheet.

12. The rotary heterogeneous Fenton oxidation reactor according to claim 8, characterized in that, The solid catalyst accounts for 50% to 85% of the volume of the metal ring.

13. The rotary heterogeneous Fenton oxidation reactor according to any one of claims 1-12, characterized in that, Also includes: A water inlet pipe is connected to a water distributor; the water inlet pipe is equipped with a wastewater inlet and a Fenton reagent inlet. The wastewater outlet is located at the bottom of the casing.

14. A wastewater treatment method, characterized in that, The rotary heterogeneous Fenton oxidation reactor according to any one of claims 1-13 includes the following steps: The pH-adjusted wastewater is mixed with Fenton reagent, and the mixture is transported to the rotary heterogeneous Fenton oxidation reactor for Fenton oxidation reaction.

15. The wastewater treatment method according to claim 14, characterized in that, The Fenton reagent comprises FeSO4 and H2O2.

16. The wastewater treatment method according to claim 15, characterized in that, The dosage of FeSO4 is 150~250 mg / L.

17. The wastewater treatment method according to claim 15, characterized in that, The dosage of H2O2 is 100~200 mg / L.

18. The wastewater treatment method according to claim 14, characterized in that, The mixing time between wastewater and Fenton reagent is 3~10 seconds.

19. The wastewater treatment method according to claim 18, characterized in that, The Fenton oxidation reaction takes 30 to 120 seconds.

20. The wastewater treatment method according to claim 18, characterized in that, The pH value of the wastewater after pH adjustment is 5.0~5.

5.

21. The wastewater treatment method according to any one of claims 14-20, characterized in that, The process of carrying out the Fenton oxidation reaction also includes a step of controlling the power of the ultrasonic vibrator to be 30-1500W.

22. The wastewater treatment method according to any one of claims 14-20, characterized in that, Ultrasonic vibrators can operate intermittently or continuously.

23. The wastewater treatment method according to claim 22, characterized in that, The frequency of intermittent operation of the ultrasonic vibrator is 6 hours / cycle to 12 hours / cycle.

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