Preparation Method of Supported Nano Copper-Iron Catalyst and Sewage Treatment Equipment

Abstract

This application relates to a supported nano copper-iron catalyst and a sewage treatment device. The supported nano copper-iron catalyst utilizes the reaction of S2- and Cu1+ with Fe3+ ions, which enhances the rate of conversion of Fe3+ to Fe2+ in the Fenton reaction, optimizes the path of Fe3+ conversion to Fe2+, and strengthens the occurrence of the Fenton reaction. The catalytic degradation of organic pollutants mainly depends on the hybrid membrane in the wastewater treatment device. Placing the catalyst on the hybrid membrane can reduce a large amount of catalyst accumulation and the problem of poor catalyst performance caused by easy deposition of the catalyst. Through the catalyst on the hybrid membrane and the original powdered catalyst in the wastewater treatment device, effective collision and contact occur among gas, solid, and liquid in the reaction zone, increasing the contact probability between the catalyst and organic pollutants in the wastewater and accelerating the reaction efficiency. The hybrid membrane is fixed in the reaction zone in a skid-mounted form, which can reduce energy consumption. At the same time, the wastewater treatment device has the advantages of convenient on-site maintenance, simple replacement, recyclability of the device, and no hazardous waste residue, etc.

Description

Technical Field

[0001] The present application relates to the technical field of sewage treatment, and particularly relates to a supported nano copper-iron catalyst and a sewage treatment device. Background Art

[0002] With the continuous expansion of the scale of the chemical production field in China, the discharge of industrial wastewater has also increased. The wastewater quality is complex, with characteristics such as high content of refractory substances, high toxicity, and poor biodegradability. Conventional water treatment technologies are difficult to treat the above problems, which has become a difficult point in industrial wastewater treatment.

[0003] Currently, for such refractory industrial wastewater, the process relies on advanced oxidation methods such as Fenton, by adding H2O2 and Fe 2+ / iron-based catalyst to the wastewater to form an oxidation system to generate hydroxyl radicals, and utilize the strong oxidizing property of hydroxyl radicals to degrade the refractory organic matter in the wastewater.

[0004] In practical applications, the traditional homogeneous Fenton process has problems such as low reaction efficiency, complex operation, difficult maintenance, and high treatment cost. The heterogeneous Fenton process has improved the problem of low reaction efficiency of homogeneous catalytic reactions to a certain extent. However, due to the disadvantages of conventional heterogeneous Fenton catalysts such as large density, easy deposition, small void fraction of particulate catalysts in fixed beds, limited water treatment capacity, and high investment cost, it is difficult to improve the problem of difficult degradation of organic matter in wastewater. Summary of the Invention

[0005] The present application aims to provide a preparation method of a supported nano copper-iron catalyst and a sewage treatment device to improve the problems that conventional heterogeneous Fenton catalysts are easy to deposit and have limited water treatment capacity, resulting in difficulty in improving the degradation of organic matter in wastewater.

[0006] To solve the above technical problems, a technical solution adopted in an embodiment of the present application is:

[0007] In a first aspect, an embodiment of the present application provides a preparation method of a supported nano copper-iron catalyst, including: grinding and mixing copper iron disulfide and cuprous oxide to obtain a first powder. Under anaerobic conditions, mixing the first powder with a ferrous salt solution, then dropping a borohydride solution, and obtaining a second powder after stirring, separating, and rinsing. Adding the second powder to an aluminum hydroxide colloid for mixing to obtain a third powder containing an aluminum hydroxide protective film, and rinsing and drying the third powder to obtain the supported nano copper-iron catalyst.

[0008] In some embodiments, the grinding and mixing of copper iron disulfide and cuprous oxide includes: grinding and mixing the copper iron disulfide and the cuprous oxide according to a mass ratio of 1:(0.5 - 1) to obtain a first powder. The particle size of the first powder is 80 nm to 120 nm.

[0009] In some embodiments, after mixing the first powder with a ferrous salt solution, dropping a borohydride solution, stirring, separating, and rinsing to obtain a second powder, includes: stirring and mixing the first powder with the ferrous salt solution for 1 h to 2 h to obtain a first mixture; the concentration of the ferrous salt solution is 0.5 mol / L to 0.8 mol / L. Drop the borohydride solution into the first mixture at a rate of 20 drops / min to 40 drops / min, and stir for 2 h to 3 h to obtain a second mixture; wherein the concentration of the borohydride solution is 1 mol / L to 1.6 mol / L. Filter the second mixture, separate the solid matter, and rinse the solid matter with a first solution to obtain a second powder. The first solution is a mixed solution of deionized water and ethanol or acetone.

[0010] In some embodiments, the preparation of the aluminum hydroxide colloid includes: under anaerobic conditions, mixing an alkaline precipitant solution with a soluble aluminum salt to obtain an aluminum hydroxide colloid. The alkaline precipitant includes at least one of sodium hydroxide, potassium hydroxide, and ammonia water. The soluble aluminum salt includes at least one of aluminum chloride, aluminum sulfate, and aluminum nitrate.

[0011] In some embodiments, the rinsing and drying of the third powder to obtain a supported nano copper-iron catalyst includes: after rinsing the third powder with a second solution, placing it at a temperature of -60°C to -40°C, and vacuum freeze-drying for 20 h to 28 h to obtain a supported nano copper-iron catalyst. Among them, the aluminum hydroxide protective film accounts for 3% to 10% of the mass of the supported nano copper-iron catalyst.

[0012] In a second aspect, an embodiment of the present application provides a method for preparing a mixed membrane, including: providing a supported nano copper-iron catalyst prepared as in the first aspect. After mixing the catalyst with a fourth powder, mixing it with dimethylacetamide to obtain a casting solution. After stirring the casting solution for 24 h to 36 h, place the casting solution on a film drawing plate and obtain a mixed membrane by the film drawing method. Among them, the fourth powder is a mixed powder of polyvinylidene fluoride and polyvinyl chloride.

[0013] In some embodiments, the mass concentration of the catalyst in the casting solution is 10% to 20%, and the mass concentration of the fourth powder in the casting solution is 20% to 30%. The mass ratio of polyvinylidene fluoride to polyvinyl chloride in the fourth powder is 1:(0.4 - 1.5).

[0014] In a third aspect, an embodiment of the present application provides a wastewater treatment device, including: a support frame, a plurality of membrane modules, a lifting frame, and a plurality of fixing members. The support frame encloses an installation space; the plurality of membrane modules are arranged in the installation space; the membrane module includes a first connecting member, a second connecting member, and a plurality of membrane units. The first connecting member and the second connecting member are arranged opposite to each other. The plurality of membrane units are all connected between the first connecting member and the second connecting member, and two adjacent first connecting members are spaced apart; the membrane unit includes a first sleeve, a second sleeve, and a hybrid membrane prepared as in the second aspect. The hybrid membrane is sleeved on the first sleeve and the second sleeve; the lifting frame is connected to the top of the support frame; the plurality of fixing members are arranged on the outer surface of the support frame.

[0015] In a fourth aspect, an embodiment of the present application provides a wastewater treatment equipment, including a separator and a plurality of wastewater treatment devices as in the third aspect. The wastewater treatment equipment includes a feeding area, a reaction area, and a separation area. The reaction area is arranged between the feeding area and the separation area; the feeding area is used to receive wastewater and reaction substances; the wastewater treatment device is arranged in the reaction area and is used to treat the wastewater flowing in from the feeding area; the separator is arranged in the separation area and is used to separate the wastewater, gas, and catalyst particles flowing out from the reaction area.

[0016] In some embodiments, the wastewater treatment equipment further includes: a plurality of aerators. The aerators are spaced apart and arranged at the bottom of the feeding area and are used to stir the wastewater and substances in the feeding area.

[0017] Different from the related art, a preparation method of a supported nano copper-iron catalyst and a sewage treatment equipment provided by an embodiment of the present application. The supported nano copper-iron catalyst utilizes S 2- and Cu 1+ to react with Fe 3+ ions, strengthening the rate of Fe 3+ converted into Fe 2+ in the Fenton reaction, optimizing the path of Fe 3+ converted into Fe 2+ and strengthening the occurrence of the Fenton reaction. The hybrid membrane prepared in the present application combines the characteristics of polyvinylidene fluoride and polyvinyl chloride membrane materials, and has the characteristics of high mechanical strength, acid and alkali corrosion resistance, high wear resistance, high surface hardness, and high internal toughness. The supported nano copper-iron catalyst and the hybrid membrane can be directly placed in the treatment pool where the Fenton reaction occurs to participate in the catalytic reaction. There are a large number of microporous structures on the hybrid membrane, which helps the nano copper-iron catalyst to contact the wastewater, providing a large number of reaction sites and promoting the occurrence of the Fenton catalytic reaction.

[0018] In the embodiments of the present application, the catalytic degradation of organic pollutants mainly relies on the mixed membrane in a large number of wastewater treatment devices. Placing the above-mentioned catalyst on the mixed membrane can reduce the accumulation of a large amount of catalyst and the problem that the catalyst is prone to deposition, resulting in poor catalyst performance. Through the catalyst on the mixed membrane and the original powdery catalyst in the equipment, effective collision and contact occur among gas, solid and liquid in the reaction zone, increasing the contact probability between the catalyst and the organic pollutants in the wastewater and accelerating the reaction efficiency. The powdery catalyst falls back and deposits under the driving force of the aerator, strengthening the catalytic effect on the organic pollutants and making the degradation of the organic pollutants in the wastewater more thorough. In addition, the mixed membrane is fixed in the reaction zone in a skid-mounted form, which can reduce energy consumption. At the same time, the wastewater treatment equipment is convenient for on-site maintenance, simple to replace, the device can be recycled, and there is no hazardous waste residue, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily illustrated by the corresponding drawings. These exemplary illustrations do not limit the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the drawings in the figures do not constitute a proportional limitation.

[0020] Figure 1 is a flowchart of a method for preparing a supported nano copper-iron catalyst provided by an embodiment of the present application;

[0021] Figure 2 is a flowchart of a method for preparing a mixed membrane provided by an embodiment of the present application;

[0022] Figure 3 is a schematic structural diagram of a wastewater treatment device provided by an embodiment of the present application;

[0023] Figure 4 is a schematic structural diagram of a membrane module provided by an embodiment of the present application;

[0024] Figure 5 is a schematic structural diagram of a membrane unit provided by an embodiment of the present application;

[0025] Figure 6 is an embodiment of the present application Figure 5 The enlarged schematic diagram of part A;

[0026] Figure 7 is a wastewater treatment device provided by an embodiment of the present application;

[0027] Figure 8 is a SEM scanning electron microscope schematic diagram of the supported nano copper-iron catalyst provided by an embodiment of the present application;

[0028] Figure 9 is a SEM scanning electron microscope schematic diagram of the mixed membrane provided by an embodiment of the present application.

[0029] Reference Numerals:

[0030] 100, wastewater treatment equipment; 10, feeding area; 11, water inlet; 12, air inlet; 13, aerator; 14, reagent addition port;

[0031] 20, reaction area; 21, wastewater treatment device; 211, support frame; 2111, first plate body; 2112, third plate body; 2113, installation space; 212, membrane module; 2121, first connector; 2122, second connector; 2123, membrane unit; 21231, first sleeve; 21232, second sleeve; 21233, hybrid membrane; 213, lifting frame; 214, fixing member; 215, first positioning member; 2151, first positioning hole; 216, second positioning member; 2161, second positioning hole; 217, third positioning member; 2171, third positioning hole;

[0032] 30, separation area; 31, gas collection area; 32, separator; 33, water outlet. Detailed Embodiments

[0033] For ease of understanding of the present invention, the present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is expressed as "fixed to" another element, it can be directly on the other element, or there can be one or more intermediate elements therebetween. When an element is expressed as "connected to" another element, it can be directly connected to the other element, or there can be one or more intermediate elements therebetween. The terms "upper", "lower", "inner", "outer", "bottom", etc. used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0034] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not used to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0035] It should be noted that if there is no conflict, the various features in the embodiments of the present application can be combined with each other, and all are within the protection scope of the present application. In addition, although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from that in the flowchart.

[0036] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] The Fenton oxidation method is to add H2O2 and catalyst Fe to the wastewater under acidic conditions 2+ to form an oxidation system, generating hydroxyl radicals with strong oxidation ability, which react with refractory organic substances in the aqueous solution to form organic radicals, destroying their structures, oxidizing and decomposing them, and effectively removing the refractory organic substances in traditional wastewater treatment technologies. There are also some problems with the traditional Fenton method. For example, it cannot fully mineralize organic substances, and part of the initial substances are converted into certain intermediate products. These intermediate products either 3+ form complexes with Fe or compete with the generation route of hydroxyl radicals, and may cause harm to the environment.

[0038] In this embodiment, the term "wastewater" or similar terms such as "wastewater" are used to generally represent a water body containing various pollutants that needs to be treated to avoid pollution problems, without specifically limiting its specific source, the pollutants contained, etc.

[0039] In the first aspect, as Figure 1 shown, Figure 1 is a flowchart of a preparation method of a supported nano copper-iron catalyst provided by an embodiment of the present application. The method includes:

[0040] Step S1: Grind and mix copper iron disulfide and cuprous oxide to obtain a first powder.

[0041] Copper iron disulfide, with the chemical formula CuFeS2, also known as chalcopyrite. In copper iron disulfide, both iron and copper elements are divalent positive. According to the fact that the total valence of the compound is zero, it can be known that the sulfur element is divalent negative.

[0042] Cuprous oxide, with the chemical formula Cu2O, also known as red copper ore. In cuprous oxide, copper is monovalent positive, presenting a bright red powdery solid, almost insoluble in water, and can disproportionate into divalent copper and copper in acidic solutions. It gradually oxidizes into black copper oxide in humid air. Cuprous oxide is mainly used to manufacture antifouling paints for ship bottoms (used to kill lower marine animals), pesticides, as well as various copper salts, analytical reagents, red glass, and is also used in the preparation of copper plating and copper alloy plating solutions.

[0043] In some embodiments, grinding and mixing copper iron disulfide and cuprous oxide specifically includes: using a planetary vacuum ball mill to perform all-round grinding on copper iron disulfide and cuprous oxide respectively. Mix the ground copper iron disulfide powder and cuprous oxide powder according to a mass ratio of 1:(0.5 - 1) to obtain a first powder. Among them, the particle size of the first powder can be ground to 80 nm to 120 nm. During the subsequent wastewater treatment process, the raw materials used in the embodiments of the present application utilize the sulfur element with a valence of -2 in copper iron disulfide and the copper element with a valence of +1 in cuprous oxide to react with Fe 3+ ions in the wastewater, strengthening the rate of Fe 3+ converted to Fe 2+ in the Fenton reaction. While promoting the Fenton reaction, the generation amount of iron sludge is reduced.

[0044] Step S3: Under anaerobic conditions, mix the first powder with a ferrous salt solution, then dropwise add a borohydride salt solution, and obtain a second powder after stirring, separating, and rinsing.

[0045] Ferrous salt refers to a salt containing ferrous ions. Fe 2+ is ferrous ion, and its salt is called ferrous salt. When elemental iron undergoes a displacement reaction, the product is a ferrous salt with a valence of +2, which has both oxidizing and reducing properties. The ferrous salt solution in the embodiments of the present application is prepared from at least one of FeSO4, ferrous sulfate, FeCl2, ferrous chloride, FeCO3, and ferrous carbonate.

[0046] Borohydride salt refers to a salt containing BH4 - ions and can be used as a reducing agent. The borohydride salt selected in the embodiments of the present application is a water-soluble borohydride salt. Further preferably, the borohydride salt solution is prepared from sodium borohydride and / or potassium borohydride.

[0047] The reaction conditions in the embodiments of the present application are carried out at a normal temperature of 25°C ± 5°C and in a nitrogen anaerobic state.

[0048] In some embodiments, after mixing the first powder with the ferrous salt solution, a borohydride solution is added dropwise, and after stirring, separating, and rinsing, a second powder is obtained. Specifically, the following steps are included: The first powder and the ferrous salt solution are stirred and mixed for 1 h to 2 h to obtain a first mixture. The concentration of the ferrous salt solution is 0.5 mol / L to 0.8 mol / L. The borohydride solution is added dropwise into the first mixture at a rate of 20 drops / min to 40 drops / min, and stirred for 2 h to 3 h to obtain a second mixture. The concentration of the borohydride solution is 1 mol / L to 1.6 mol / L. The second mixture is filtered through a suction pump to separate the solid matter, and the solid matter is rinsed 2 to 3 times with a first solution to obtain the second powder. The first solution is a mixed solution of deionized water and ethanol or acetone. In the present application, after the first powder is mixed with the ferrous salt solution, ferrous ions and a small amount of copper ions will adhere to the surface of the first powder during the stirring process. When reacting with the borohydride, nano-zero-valent iron and nano-sized copper parts will be formed on the surface of the first powder. The specific reaction equations are as follows:

[0049] Fe 2+ +3BH4 - +3H2O→Fe+3B(OH)3+9H2;

[0050] Cu 2+ +2BH4 - +6H2O→Cu+2B(OH)3+8H2;

[0051] In the second powder prepared in the embodiments of the present application, since the second powder contains zero-valent nano-iron and zero-valent nano-copper, after contacting with the wastewater, electrons will be lost and oxidized. The generated electrons can not only promote the participation of copper iron disulfide and cuprous oxide in the Fenton reaction, but also convert Fe 3+ to generate Fe 2+ , strengthening the Fenton reaction.

[0052] Step S5: The second powder is added to the aluminum hydroxide colloid and mixed to obtain a third powder containing an aluminum hydroxide protective film. The third powder is rinsed and dried to obtain a supported nano-copper iron catalyst.

[0053] The second powder is added to the aluminum hydroxide colloid and stirred for 1 h to 2 h. After mixing them evenly, suction filtration is carried out to obtain a third powder containing an aluminum hydroxide protective film.

[0054] The reaction conditions in the embodiments of the present application are carried out at a normal temperature of 25°C ± 5°C and in a nitrogen anaerobic state.

[0055] In some embodiments, the preparation of aluminum hydroxide colloid includes: under anaerobic conditions, preparing an alkaline precipitant solution with an appropriate concentration, and uniformly dropping the above-mentioned alkaline precipitant solution into a soluble aluminum salt solution. During the titration process, the alkaline precipitant and the soluble aluminum salt solution are mixed evenly and react to form aluminum hydroxide colloid. Among them, the alkaline precipitant includes at least one of sodium hydroxide, potassium hydroxide, and ammonia water; the soluble aluminum salt includes at least one of aluminum chloride, aluminum sulfate, and aluminum nitrate.

[0056] In some embodiments, the third powder is rinsed and dried to obtain a supported nano copper-iron catalyst, specifically including: after rinsing the third powder 2 to 3 times with a second solution, it is placed at a temperature of -60°C to -40°C and vacuum freeze-dried for 20h to 28h to obtain a supported nano copper-iron catalyst. Among them, the aluminum hydroxide protective film accounts for 3% to 8% of the mass of the supported nano copper-iron catalyst, and the second solution is deionized water. Due to the actions of hydrogen bonds, electrostatic forces, and van der Waals forces, etc., the aluminum hydroxide colloid has a strong adsorption and binding force for particulate matter. It can not only form an anti-oxidation protective layer on the second powder to protect the physical properties of the prepared catalyst, but also promote the subsequent combination with the fourth powder. Among them, the fourth powder is a mixed powder of polyvinylidene fluoride and polyvinyl chloride.

[0057] In a second aspect, as Figure 2 shown, Figure 2 is a flowchart of a method for preparing a mixed membrane provided by an embodiment of the present application. The method includes:

[0058] Step S2: Provide a supported nano copper-iron catalyst prepared by any of the preparation methods in the first aspect.

[0059] Step S4: After mixing the catalyst with the fourth powder, mix it with dimethylacetamide to obtain a casting solution.

[0060] Step S6: After stirring the casting solution for 24h to 36h, place the casting solution on a film-drawing plate and obtain a mixed membrane by the film-drawing method; among them, the fourth powder is a mixed powder of polyvinylidene fluoride and polyvinyl chloride.

[0061] Dimethylacetamide, with the full name of N,N-dimethylacetamide. It is commonly used as an aprotic polar solvent. It is a colorless transparent liquid and flammable. It can be arbitrarily mixed with organic solvents such as water, alcohol, ether, ester, benzene, chloroform, and aromatic compounds.

[0062] Film-drawing method: Take a certain mass of the casting solution and place it on a flat and clean film-drawing plate. The film-drawing plate is placed in a ventilated and shaded place. After sufficient drying, peel it off. Observe the peeled mixed membrane, and moderately stretch the one with high transparency and good quality to obtain a mixed membrane with uniform thickness.

[0063] Polyvinylidene fluoride, abbreviated as PVDF, is a highly non-reactive thermoplastic fluoropolymer. It can be synthesized by the polymerization of 1,1-difluoroethylene. It is soluble in strong polar solvents such as dimethylacetamide. It has excellent properties such as anti-aging, chemical resistance, weather resistance, and ultraviolet radiation resistance. It can be used as an engineering plastic for making corrosion-resistant equipment for sealing rings, capacitors, and also as coatings, insulating materials, and ion exchange membrane materials, etc.

[0064] Polyvinyl chloride, abbreviated as PVC in English, is a polymer formed by the polymerization of vinyl chloride monomer (VCM) under the action of initiators such as peroxides and azo compounds or under the action of light and heat according to the free radical polymerization reaction mechanism. Vinyl chloride homopolymers and vinyl chloride copolymers are collectively called vinyl chloride resins. Polyvinyl chloride is a white powder with an amorphous structure, with a small degree of branching, a glass transition temperature of 77 °C to 90 °C, and starts to decompose at about 170 °C. It has poor stability to light and heat. When it is above 100 °C or exposed to sunlight for a long time, it will decompose to produce hydrogen chloride.

[0065] In some embodiments, the mass concentration of the catalyst in the casting solution is 10% to 20%, the mass concentration of the fourth powder in the casting solution is 20% to 30%, and the mass ratio of polyvinylidene fluoride to polyvinyl chloride in the fourth powder is 1:(0.4 - 1.5).

[0066] In the embodiments of the present application, the mixed membranes prepared by the above method can be applied to the treatment of industrial wastewater such as photovoltaic wastewater, dye wastewater, coking wastewater, and agricultural and pharmaceutical wastewater. In the traditional Fenton reaction and the reaction process of traditional iron-based catalysts, a large amount of alkali solution needs to be added to neutralize the discharged water. The reaction between the alkali solution and the iron ions in the wastewater will produce a large amount of hazardous waste substances, iron sludge. The generation of iron sludge increases the operating cost, and its cost accounts for more than 25%. The supported nano copper-iron catalyst and the mixed membrane prepared in the present application can reduce the sludge production by 40% to 50% in wastewater treatment, thereby reducing the usage amount of the alkali solution and reducing the operating cost.

[0067] The mixed membrane prepared in the present application combines the characteristics of polyvinylidene fluoride and polyvinyl chloride membrane materials, and has the characteristics of high mechanical strength, acid and alkali corrosion resistance, high wear resistance, high surface hardness and high internal toughness. The supported nano copper-iron catalyst and the mixed membrane can be directly placed in the treatment pool where the Fenton reaction occurs to participate in the catalytic reaction. There are a large number of microporous structures on the mixed membrane, which helps the nano copper-iron catalyst to contact the wastewater to provide a large number of reaction sites and promote the occurrence of the Fenton catalytic reaction. At the same time, the supported nano copper-iron catalyst utilizes S 2- and Cu 1+ react with Fe 3+ ions to strengthen the conversion of Fe 3+ to Fe 2 +rate, optimized Fe 3+ transformed into Fe 2+ path, strengthening the occurrence of the Fenton reaction.

[0068] In a third aspect, as Figure 3 shown, Figure 3 FIG. 11 is a schematic structural diagram of a wastewater treatment device 21 provided by an embodiment of the present application. The wastewater treatment device 21 includes a support frame 211, a plurality of membrane modules 212, a lifting frame 213, and a plurality of fixing members 214.

[0069] For the above-mentioned support frame 211, it includes a first plate body 2111 and a second plate body (not labeled in the figure) oppositely arranged in the first direction X, and a third plate body 2112 and a fourth plate body (not labeled in the figure) oppositely arranged in the second direction Y. The first plate body 2111, the second plate body, the third plate body 2112, and the fourth plate body jointly enclose an installation space 2113. Wastewater can flow from the bottom end of the support frame 211 along the third direction Z through the installation space and out from the top end of the support frame 211.

[0070] In some embodiments, when observed along the third direction Z, the support frame 211 can be enclosed by the first plate body 2111, the second plate body, the third plate body 2112, and the fourth plate body into a rectangle, an ellipse, or a circle.

[0071] For the above-mentioned plurality of membrane modules 212, in combination with Figure 3 and Figure 4 FIG. 24, the membrane module 212 is disposed in the installation space 2113. The membrane module 212 includes a first connector 2121, a second connector 2122, and a plurality of membrane units 2123. Along the third direction Z, the first connector 2121 and the second connector 2122 are oppositely arranged, and a plurality of membrane units 2123 are all connected between the first connector 2121 and the second connector 2122, and along the second direction Y, adjacent first connectors 2121 are spaced apart.

[0072] In some embodiments, please refer to Figure 3, a first positioning member 215 and a second positioning member 216 are respectively provided on the first plate body 2111 and the second plate body on the support frame 211. The first positioning member 215 and the second positioning member 216 are respectively provided with a plurality of first positioning holes 2151 and a plurality of second positioning holes 2161. The first connecting member 2121 is inserted between the first positioning hole 2151 and the second positioning hole 2161 for positioning the membrane module 212 on the support frame 211. Similarly, a third positioning member 217 and a fourth positioning member (not marked in the figure) are also provided on the first plate body 2111 and the second plate body. The third positioning member 217 and the fourth positioning member are respectively provided with a plurality of third positioning holes 2171 and a plurality of fourth positioning holes (not marked in the figure). The second connecting member 2122 is inserted between the third positioning hole 2171 and the fourth positioning hole for positioning the membrane module 212 on the support frame 211.

[0073] For the above-mentioned membrane unit 2123, please refer to Figure 5 and Figure 6 , the membrane unit 2123 includes a first sleeve 21231, a second sleeve 21232 and a hybrid membrane 21233 prepared as described in the second aspect above. The hybrid membrane 21233 is sleeved on the first sleeve 21231 and the second sleeve 21232. Among them, the hybrid membrane 21233 is processed into a filamentous or strip shape with a width of 0.1 cm to 0.2 cm.

[0074] For the above-mentioned lifting frame 213, please refer to Figure 3 , which is connected to the top of the support frame 211. The lifting frame 213 can be simultaneously arranged on the first plate body 2111 and the second plate body, or can be simultaneously arranged on the third plate body 2112 and the fourth plate body for lifting the waste treatment device. When observed along the second direction Y, the shape of the lifting frame 213 can be any one of a semicircle, a triangle, and a rectangle.

[0075] For the above-mentioned plurality of fixing members 214, please refer to Figure 3 , the fixing members 214 are arranged on the outer surface of the support frame 211. Further, a plurality of fixing members 214 can be respectively arranged on the outer surfaces of the first plate body 2111 and the second plate body. Along the first direction X, the fixing members 214 on the outer surface of the first plate body 2111 are arranged at the same intervals. The fixing members 214 are used for clamping and fixing to an external device, such as being fixed in a Fenton fluidized bed for wastewater treatment.

[0076] The wastewater treatment device prepared in this application has a hybrid membrane forming a membrane unit through a sleeve, and several membrane units form a membrane module, which is arranged in an installation space. When the hybrid membrane needs to be replaced, the membrane units on the membrane module can be directly replaced, or the entire membrane module can be replaced, making the operation convenient. At the same time, the membrane units are regularly arranged in the installation space, rationally utilizing the use space of the wastewater treatment device, increasing the contact area between the wastewater and the catalyst, and reducing the problems of space blockage caused by catalyst accumulation and low catalyst utilization rate.

[0077] Fourthly, as Figure 7 shown, Figure 7 Fig. 7 is a wastewater treatment device 100 provided by an embodiment of the present application. The wastewater treatment device 100 includes a separator 32 and several wastewater treatment devices 21 as described in any embodiment of the third aspect.

[0078] The wastewater treatment device 100 includes a feeding area 10, a reaction area 20, and a separation area 30. The reaction area 20 is arranged between the feeding area 10 and the separation area 30.

[0079] For the above-mentioned feeding area 10, it includes a water inlet 11, a gas inlet 12, and a reagent addition port 14. The water inlet 11 of the feeding area 10 is used to receive wastewater, and the gas inlet 12 and the reagent addition port 14 are used to receive reaction substances required during the wastewater treatment process.

[0080] For the above-mentioned wastewater treatment device 21, the wastewater treatment device 21 is arranged in the reaction area 20 and is used to treat the wastewater flowing in from the feeding area 10.

[0081] For the above-mentioned separator 32, please continue to refer to Figure 7 , the separator 32 is arranged in the separation area 30 and is used to separate the wastewater, gas, and catalyst particles flowing out from the reaction area 20. The separation area 30 is provided with a water outlet 33 for discharging the treated wastewater, and the separation area 30 is also provided with a gas collection area 31 for collecting the gas generated by the reaction. For example, the separator 32 can be a triangular separator 32, which is mainly used for three-phase separation. After the catalyst particles in the wastewater collide with the triangular separator 32, the catalyst flows back to the reaction area 20, and the treated gas and wastewater pass through the triangular separator 32. The treated wastewater is discharged from the water outlet 33, and the gas enters the gas collection area 31 for collection.

[0082] In some embodiments, please refer to Figure 7, the wastewater treatment device 100 further includes: a plurality of aerators 13, which are arranged at intervals at the bottom of the feeding area 10. The aerator 13 can use a blower to transport air through an air delivery pipeline to the aerator device arranged at the bottom of the feeding area, and diffuse and escape in the form of bubbles, which can oxygenate and stir the water body, prevent the catalyst powder and organic substances in the wastewater from settling, ensure sufficient contact between the catalyst particles, reagents and the organic substances in the sewage, and is used to stir the wastewater and substances in the feeding area 10.

[0083] In some embodiments, due to the relatively large density of the catalyst, it is easy to fall back and deposit during the reaction process. Therefore, the concentration of the catalyst in the wastewater treatment device 100 should not be too high, and the concentration of the powdered supported nano copper-iron catalyst is maintained at 0.2 g / L to 1 g / L.

[0084] In the embodiment of the present application, when the hybrid membrane 21233 is used in the wastewater treatment device 21 for Fenton catalytic reaction, only part of the catalyst needs to be replenished regularly, or the membrane module 212 needs to be replaced, making the replenishment of the catalyst in the wastewater treatment device 100 more convenient and highly operable. Multiple wastewater treatment devices 21 are simultaneously applied to the wastewater treatment device 100, which can make the hybrid membrane 21233 fully contact with the wastewater and enhance the Fenton catalytic effect.

[0085] The present application also proposes a wastewater treatment method for the wastewater treatment device 100. The specific steps include: first, adjusting the wastewater to an acidic environment, adding H2O2, and then entering the wastewater treatment device 100 from the water inlet 11. An appropriate amount of powdered supported nano copper-iron catalyst is added to the wastewater treatment device 100, and power is provided by the aerator 13 to stir and mix the catalyst, wastewater, and substances such as acid, H2O2, and Fe 2+ in the wastewater to degrade the refractory substances in the wastewater. The possible reactions that may occur in the wastewater treatment device 100 are as follows:

[0086] (1), Fe 0 +RH→R·+H2O+Fe 2+ / Fe 3+ ;

[0087] (2), Cu 0 +RH→R·+H2O+Cu 2+ ;

[0088] (3), Fe 0 +H2O2→Fe 3+ +HO - +HO·;

[0089] (4), Fe 0 +2H2O2→Fe 2+ +2HO -+2HO·;

[0090] (5)、H2O2 + Fe 2+ →Fe 3+ + HO - + HO·;

[0091] (6)、RH + HO· → R· + H2O;

[0092] (7)、Cu 0 + Fe 3+ →Fe 2+ + Cu 2+ / Cu + ;

[0093] (8)、Cu + + Fe 3+ →Fe 2+ + Cu 2+ ;

[0094] (9)、Fe 0 + Cu 2+ / Cu + →Fe 3+ + Cu;

[0095] (10)、Fe 0 + Fe 3+ →2Fe 2+ ;

[0096] (11)、S 2- + 14Fe 3+ + 8H2O → 15Fe 2+ + 2SO4 2- + 16H + 。

[0097] Among them, RH represents the organic pollutants in the wastewater; R· represents the product after the reaction of the organic pollutants.

[0098] The reaction processes (1) to (6) are the degradation reactions of organic pollutants by the simulated supported nano copper-iron catalyst, especially involving the reactions of nano zero-valent iron and nano zero-valent copper directly with organic pollutants, and the Fenton reaction.

[0099] The reactions (7) to (11) are the ion conversion reactions involved in the wastewater treatment process, which more intuitively explains the principle of inhibiting the generation of a large amount of iron sludge.

[0100] In the embodiments of the present application, the catalytic degradation of organic pollutants mainly relies on the hybrid membrane 21233 in a large number of wastewater treatment devices 21. Placing the catalyst on the hybrid membrane 21233 can reduce the accumulation of a large amount of catalyst and the problem that the catalyst is prone to deposition, resulting in poor catalyst performance. Through the catalyst on the hybrid membrane 21233 and the original powdery catalyst in the equipment, effective collision and contact occur among gas, solid and liquid in the reaction zone 20, increasing the contact probability between the catalyst and the organic pollutants in the wastewater and accelerating the reaction efficiency. The powdery catalyst falls back and deposits under the driving force of the aerator 13, strengthening the catalytic effect on the organic pollutants and making the degradation of the organic pollutants in the wastewater more thorough. In addition, the hybrid membrane 21233 is fixed in the reaction zone 20 in a skid-mounted form, which can reduce energy consumption. At the same time, the wastewater treatment equipment 100 has the advantages of being convenient for on-site maintenance, simple to replace, recyclable, and having no hazardous waste residue.

[0101] In order to fully illustrate the actual use effects of the hybrid membrane 21233 and the wastewater treatment equipment 100 provided in the embodiments of the present application, the following is described in combination with specific embodiments:

[0102] Example 1:

[0103] Based on the preparation method of the hybrid membrane and the application of the hybrid membrane to the wastewater treatment equipment 100 for degrading pyridine industrial wastewater.

[0104] (1) Select CuFeS2 and Cu2O, and grind CuFeS2 and Cu2O into particles with a particle size of 80 nm to 100 nm respectively by using an all-round planetary vacuum ball mill. According to the mass ratio of CuFeS2 and Cu2O being 1:(0.5 - 1), form the first powder.

[0105] (2) Under an anaerobic environment, immerse the first powder in a ferrous salt solution with a concentration of 0.5 mol / L to 0.8 mol / L, and stir fully for 1 h to 2 h. Subsequently, dropwise add a borohydride solution with a concentration of 1 mol / L to 1.6 mol / L at a rate of 20 drops / min to 40 drops / min, stir and react for 2 h to 3 h. After solid-liquid separation, take out the solid powder and rinse it 2 - 3 times successively with a mixed solution of deionized water and ethanol or acetone to obtain the second powder.

[0106] (3) Prepare an appropriate concentration of NaOH solution using anaerobic water, and titrate the NaOH solution into the anaerobic aluminum salt solution at a constant rate. During the titration process, ensure that the NaOH solution and the anaerobic aluminum salt solution are evenly mixed and react to obtain aluminum hydroxide colloid. Add the second powder to the aluminum hydroxide colloid, stir for 1 to 2 hours, and then filter to obtain the third powder with an aluminum hydroxide protective film. Rinse the third powder 2 to 3 times with deionized water, and dry it in a vacuum freeze dryer at -60°C to -40°C for 20 to 28 hours to obtain the supported nano copper-iron catalyst, where the aluminum hydroxide protective film accounts for 3% to 10% of the mass of the supported nano copper-iron catalyst.

[0107] (4) Mix the supported nano copper-iron catalyst and the fourth powder evenly, and put them into a dimethylacetamide solvent to prepare a casting solution. After stirring the casting solution for 24 to 36 hours, a mixed film 21233 is formed. Among them, the fourth powder is a powder mixture of polyvinylidene fluoride and polyvinyl chloride with a mass ratio of 1:(0.4 to 1.5), the mass concentration of the catalyst in the casting solution is 10% to 20%, and the mass concentration of the fourth powder in the casting solution is 20% to 30%.

[0108] (5) Process the mixed film 21233 into a strip shape with a thickness of 0.1 cm and a width of 3 cm. Sleeve the mixed film 21233 on a sleeve to form a membrane unit 2123. Combine several membrane units 2123 to form a membrane module 212, and then fix it on a support frame 211 to form a wastewater treatment device 21. Fix the wastewater treatment device 21 in a fluidized bed where Fenton reaction occurs through several fixing parts 214 on the wastewater treatment device 21 to form a wastewater treatment equipment 100.

[0109] (6) The effect test of the wastewater treatment equipment 100 for degrading pyridine industrial wastewater is as follows:

[0110] Prepare a 500 mg / L picloram solution, inlet water from the inlet 11 at a rate of 200 L / h, with a height-to-diameter ratio of 4:1, and stay in the wastewater treatment equipment 100 for 1 hour. The content of the powdered catalyst in the equipment is 0.5 g / L, the steam-water ratio is 1:1, the aeration intensity is 1 m of water depth, and the wastewater treatment device 21 accounts for 2 / 3 of the wastewater treatment equipment 100. Under the continuous operation of the wastewater treatment equipment 100, the removal rate of picloram is measured to be 75%. In the blank experiment, the removal rate of picloram in the heterogeneous Fenton catalytic reaction is 45%, and the removal rate of picloram in the traditional homogeneous Fenton catalytic reaction is only 30%.

[0111] Please refer to Figure 8 , Figure 8It is a schematic SEM diagram of the supported nano copper-iron catalyst provided by the embodiment of the present application. It can be seen from the figure that the catalyst mostly presents as spherical, and multiple spherical particles are attached together. These spherical substances may be nano zero-valent iron and nano zero-valent copper attached to the first powder.

[0112] Please refer to Figure 9 , Figure 9 It is a schematic SEM diagram of the hybrid membrane provided by the embodiment of the present application. It can be seen from the figure that the catalyst particles are embedded in the casting solution. There are a large number of microporous structures on the hybrid membrane 21233. This structure helps the nano copper-iron catalyst to contact the wastewater, providing a large number of reaction sites to promote the occurrence of the Fenton catalytic reaction for sufficient contact with the wastewater. Moreover, the catalyst particles are evenly distributed in the casting solution, making full use of the use space of the hybrid membrane 21233 and improving the efficiency of wastewater treatment.

[0113] In summary, the hybrid membrane 21233 prepared in the present application combines the characteristics of polyvinylidene fluoride and polyvinyl chloride membrane materials, and has the characteristics of high mechanical strength, acid and alkali corrosion resistance, high wear resistance, high surface hardness and high internal toughness. The supported nano copper-iron catalyst and the hybrid membrane 21233 can be directly placed in the treatment tank where the Fenton reaction occurs to participate in the catalytic reaction. The large number of microporous structures on the hybrid membrane 21233 help the nano copper-iron catalyst to contact the wastewater, providing a large number of reaction sites to promote the occurrence of the Fenton catalytic reaction. At the same time, the supported nano copper-iron catalyst utilizes S 2- and Cu 1+ to react with Fe 3+ ions, strengthening the rate of Fe 3+ converting to Fe 2+ in the Fenton reaction, optimizing the path of Fe 3+ converting to Fe 2+ and strengthening the occurrence of the Fenton reaction. The catalyst on the hybrid membrane 21233 of the wastewater treatment equipment 100 provided in the present application, as well as the original powdery catalyst in the equipment, can effectively collide and contact among gas, solid and liquid in the reaction zone 20, increasing the contact probability between the catalyst and the organic pollutants in the wastewater and accelerating the reaction efficiency. The powdery catalyst falls back and deposits under the power of the aerator 13, strengthening the catalytic effect on the organic pollutants and making the degradation of the organic pollutants in the wastewater more thorough. In addition, the hybrid membrane 21233 is fixed in the reaction zone 20 in a skid-mounted form, which can reduce energy consumption. At the same time, the wastewater treatment equipment 100 is convenient for on-site maintenance, simple to replace, the device can be recycled, and there is no hazardous waste residue, etc.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; under the idea of the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order, and there are many other variations in different aspects of the present application as above. For the sake of brevity, they are not provided in detail; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present application.

Claims

1. A method for preparing a mixed membrane, characterized in that, Including: Providing a supported nano copper-iron catalyst, mixing the supported nano copper-iron catalyst with a powder mixture of polyvinylidene fluoride and polyvinyl chloride, and then mixing with dimethylacetamide to obtain a casting solution; After stirring the casting solution for 24 h to 36 h, placing the casting solution on a film drawing plate, and obtaining a mixed film by the film drawing method; The preparation method of the supported nano copper-iron catalyst includes: Grinding and mixing copper iron disulfide and cuprous oxide to obtain a first powder; Under anaerobic conditions, mixing the first powder with a ferrous salt solution, then dropping a borohydride salt solution, stirring, separating, and rinsing to obtain a second powder; Adding the second powder to an aluminum hydroxide colloid for mixing to obtain a third powder containing an aluminum hydroxide protective film, and rinsing and drying the third powder to obtain a supported nano copper-iron catalyst.

2. The preparation method according to claim 1, characterized in that, The grinding and mixing of copper iron disulfide and cuprous oxide includes: Grinding and mixing the copper iron disulfide and the cuprous oxide according to a mass ratio of 1:(0.5 - 1) to obtain a first powder; The particle size of the first powder is 80 nm to 120 nm.

3. The preparation method according to claim 1, wherein The process of mixing the first powder with a ferrous salt solution, then dropping a borohydride salt solution, stirring, separating, and rinsing to obtain a second powder includes: Stirring and mixing the first powder with a ferrous salt solution for 1 h to 2 h to obtain a first mixture; the concentration of the ferrous salt solution is 0.5 mol / L to 0.8 mol / L; Dropping the borohydride salt solution into the first mixture at a rate of 20 drops / min to 40 drops / min, and stirring for 2 h to 3 h to obtain a second mixture; wherein the concentration of the borohydride salt solution is 1 mol / L to 1.6 mol / L; Filtering the second mixture to separate the solid matter, and rinsing the solid matter with a first solution to obtain a second powder; The first solution is a mixed solution of deionized water and ethanol or acetone.

4. The preparation method according to claim 1, characterized in that, The preparation of the aluminum hydroxide colloid includes: Under anaerobic conditions, mixing an alkaline precipitant solution with a soluble aluminum salt to obtain an aluminum hydroxide colloid; The alkaline precipitant includes at least one of sodium hydroxide, potassium hydroxide, and ammonia water; The soluble aluminum salt includes at least one of aluminum chloride, aluminum sulfate, and aluminum nitrate.

5. The preparation method according to claim 4, characterized in that, The process of rinsing and drying the third powder to obtain a supported nano copper-iron catalyst includes: Rinsing the third powder with a second solution, and then placing it at a temperature of -60°C to -40°C and vacuum freeze-drying for 20 h to 28 h to obtain a supported nano copper-iron catalyst; Wherein, the aluminum hydroxide protective film accounts for 3% to 10% of the mass of the supported nano copper-iron catalyst.

6. The preparation method according to claim 1, characterized in that, The mass concentration of the supported nano copper-iron catalyst in the casting solution is 10% to 20%, and the mass concentration of the powder mixture of polyvinylidene fluoride and polyvinyl chloride in the casting solution is 20% to 30%; The mass ratio of polyvinylidene fluoride to polyvinyl chloride is 1:(0.4 - 1.5).

7. A wastewater treatment device, characterized in that, Including: A support frame, enclosing an installation space; A number of membrane modules are arranged in the installation space; the membrane module includes a first connecting piece, a second connecting piece and a number of membrane units, the first connecting piece and the second connecting piece are arranged opposite to each other, the number of membrane units are all connected between the first connecting piece and the second connecting piece, and two adjacent first connecting pieces are arranged at intervals; The membrane unit includes a first sleeve, a second sleeve and a mixed membrane prepared by the preparation method according to claim 1, and the mixed membrane is sleeved on the first sleeve and the second sleeve; A lifting frame is connected to the top end of the support frame; A number of fixing pieces are arranged on the outer surface of the support frame.

8. A wastewater treatment device, characterized in that, It includes a separator and a number of wastewater treatment devices according to claim 7; The wastewater treatment equipment includes a feeding area, a reaction area and a separation area, and the reaction area is arranged between the feeding area and the separation area; The feeding area is used for receiving wastewater and reaction substances; The wastewater treatment device is arranged in the reaction area and is used for treating the wastewater flowing in from the feeding area; The separator is arranged in the separation area and is used for separating the wastewater, gas and catalyst particles flowing out from the reaction area.

9. The wastewater treatment equipment according to claim 8, wherein It also includes: A number of aerators; The aerators are arranged at intervals at the bottom of the feeding area and are used for stirring the wastewater and substances in the feeding area.

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