A micro-electrolysis hollow iron-carbon filler tube and its preparation method and application

Abstract

The present application discloses a micro-electrolysis hollow iron-carbon filler tube and its preparation method and application, belonging to the technical field of iron-carbon micro-electrolysis filler. The iron-carbon filler is hollow and tubular, and the tube wall is distributed with semicircular hole convex pieces bent inwardly. It is prepared by extrusion molding, high-temperature reduction sintering, and punching and punching. When used in iron-carbon micro-electrolysis to treat wastewater, the inward-protruding semicircular convex pieces play the role of multiple gas and water mixing, forming multi-directional turbulence in the tube, and can drive the formation of turbulence outside the tube wall, increasing the gas-liquid-solid three-phase contact efficiency, while improving the scrubbing effect of gas and water on the inner and outer walls of the tube, preventing the ferrous iron and iron hydroxide generated by the reaction from forming a passivation film on the filler surface, and avoiding the performance degradation or even failure of the filler.

Description

Technical Field

[0001] The present application belongs to the technical field of iron-carbon micro-electrolysis fillers, and specifically relates to a micro-electrolysis hollow iron-carbon filler tube and a preparation method and application thereof. Background Art

[0002] Iron-carbon micro-electrolysis technology uses iron and carbon as electrodes to form a primary cell, which decomposes the difficult-to-degrade organic pollutants in wastewater into small molecular organic matter that is easily biodegradable. It can not only remove pollutants but also improve the biodegradability of wastewater. The micro-electrolysis reaction process mainly includes the primary cell reaction (the potential difference between iron and carbon is formed, and the organic matter in the water is electrochemically degraded), the redox reaction (the new ecological Fe is generated in the system), and the oxidation-reduction reaction (the new ecological Fe is generated in the system). 2+ and [H], which easily react with oxidizing substances in water, thereby changing the structure of some organic polymers), adsorption and precipitation (Fe 2+ and Fe 3+ The ferric hydroxide complex generated by hydrolysis has a net-capturing adsorption effect, assisting in the co-precipitation removal of some pollutants).

[0003] Currently, there are many specifications of iron-carbon fillers on the market, such as spherical, oblate, cylindrical or gear-shaped, with sizes ranging from 1 to 5 cm. In the application process, a fixed bed method is mostly used, that is, water and air distribution pipelines are set at the bottom of the pool, and a porous support plate is set above. Iron-carbon fillers are installed on the upper part of the support plate for wastewater treatment reaction. Iron-carbon fillers of different specifications are mostly dumped into the reactor in a disordered manner. The filling height varies according to the quality of the treated water, usually several meters high. The filler particles are in contact with each other, forming irregular gaps of different sizes in the middle. The water flow and air flow pre-adjusted to acidity pass through the bottom of the filler and through the filler gaps to form a three-phase contact reaction, which degrades the pollutants. At the same time, due to the electrochemical reaction, the elemental iron in the iron-carbon precipitates to form divalent iron ions. Subsequently, the pH is adjusted to form iron sludge precipitation and separation to achieve water discharge. During operation, iron-carbon packing often experiences compaction and passivation. This is due to the partial hydrolysis of the generated ferrous ions under aeration, producing ferrous hydroxide and ferric hydroxide complexes. These complexes tend to coat the interstices between the iron-carbon packing particles and the packing surface where the air and water flows are not sufficiently turbulent, forming a passivation film. This obstructs the contact surface between the iron and carbon, reducing the efficiency of the galvanic cell. Over time, the passivation buildup causes the iron-carbon particles to adhere to each other, leading to compaction. To prevent this, the iron-carbon packing must be regularly backwashed with air and water to reduce the deposits of passivation and iron hydroxide in the packing interstices. Furthermore, most commercially available iron-carbon packings are centimeter-sized, fixedly packed, with particles contacting each other, resulting in a small effective surface area. Engineering practices often require a 40-50% fill ratio in the reaction tank or tower to achieve optimal pollutant removal. This not only requires a large amount of packing and high investment, but also further increases the risk of compaction during operation.

[0004] In related technologies, for example, Chinese invention patent publication number CN102336456A describes an irregular micro-electrolytic iron-carbon filler and discloses the following technical solution: an irregular micro-electrolytic iron-carbon filler in a block shape, with at least one irregular protrusion and at least one irregular groove respectively arranged on the opposite end faces of the filler; the irregular protrusions and irregular grooves are arranged correspondingly up and down on the opposite end faces; a first side face is sandwiched between the opposite end faces of the filler, the opposite side of the first side face is the second side face, and the irregular protrusions and / or irregular grooves are located between the first side face and the second side face; the height of the irregular protrusions and / or the depth of the irregular grooves are different on the first side face and the second side face; the irregular protrusions and irregular grooves are roughly gear-shaped; the filler is tilted as a whole and / or has an arc; the height of the filler is 40 to 60 mm and the length is 50 to 120 mm. Due to its irregularity, the iron-carbon filler of this invention can greatly increase the contact reaction area and improve the sewage treatment effect. In addition, due to the irregularity of the filler's protrusions and grooves, backwashing is not only easy, but also has a good cleaning effect, greatly extending the service life of the filler. However, this irregular filler has gear-shaped protrusions, which may cause wear on the edges and corners. The protrusions have relatively low strength and hardness relative to the overall strength and hardness of the filler, and are easily broken and shattered during the filling process, which is not conducive to maintaining structural stability. Summary of the Invention

[0005] 1. Problem to be solved

[0006] The purpose of the present application is to overcome one of the technical problems of the existing iron-carbon filler in the use process, that is, the effective surface area is small, the contact reaction efficiency is low, and the disordered fixed bed accumulation easily causes the filler to become compacted and passivated, and to provide a micro-electrolysis hollow iron-carbon filler tube and its preparation method and application; the iron-carbon filler is hollow tubular, and the tube wall is distributed with semicircular hole convex pieces bent inwardly, and is prepared by extrusion molding, high-temperature reduction sintering, and punching and punching. When used in iron-carbon micro-electrolysis to treat wastewater, the inwardly protruding semicircular convex pieces play the role of multiple gas mixing and water mixing, so that multi-directional turbulence is formed in the tube, and can drive the formation of turbulence outside the tube wall, thereby increasing the gas-liquid-solid three-phase contact efficiency, and at the same time improving the scrubbing effect of gas and water on the inner and outer walls of the tube, preventing the ferrous iron and iron hydroxide generated by the reaction from forming a passivation film on the filler surface, and avoiding the performance degradation or even failure of the filler.

[0007] 2. Technical solution

[0008] In order to solve the above problems, the technical solutions adopted in this application are as follows:

[0009] The present application provides a method for preparing a micro-electrolysis hollow iron-carbon filler tube, which comprises uniformly mixing ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder in proportion, adding water and extruding and injection molding to obtain a hollow iron-carbon tube green body, sending the green body into a high-temperature reducing atmosphere furnace for calcination, and then drilling and punching the tube wall to create a semicircular hole protrusion bent inwardly on the tube, thereby finally obtaining a micro-electrolysis hollow iron-carbon filler tube.

[0010] Furthermore, the semicircular protrusions are symmetrically formed with two holes on both sides at the same circumferential position of the tube wall.

[0011] Furthermore, the added mass ratio of the above-mentioned ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder is 90-95:10-15:3-5:0-3.

[0012] Furthermore, the carbon powder is one of coke, activated carbon and graphite.

[0013] Furthermore, the catalyst precursor powder is one or more combinations of titanium oxide, nickel oxide, and copper oxide.

[0014] Furthermore, the particle sizes of the ferroferric oxide, carbon powder, polyvinyl alcohol powder and catalyst precursor powder are all greater than or equal to 200 meshes.

[0015] Furthermore, the amount of water is 8% to 12% of the total mass of the mixture of ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder.

[0016] Furthermore, the specific steps of adding water and extruding and injection molding to prepare the hollow iron-carbon tube green body include:

[0017] (1) The pre-mixed material powder is mixed with water and beaten. The beating equipment that contacts the material powder is made of hard plastic to avoid magnetic attraction with ferroferric oxide, which may affect the uniformity of the material.

[0018] (2) The polyvinyl alcohol in the material powder reacts with water to form adhesiveness, and the mixed material becomes a wet material, which enters the hollow tube mold and is pushed and extruded by high pressure to extrude the hollow iron-carbon tube green body.

[0019] Furthermore, the outer diameter of the hollow iron-carbon tube green body is 4 to 5 cm, and the difference between the outer diameter and the inner diameter is 1 to 1.6 cm, that is, the wall thickness is 0.5 to 0.8 cm.

[0020] Furthermore, the length of the hollow iron-carbon tube green body is 0.5 to 2 m.

[0021] Furthermore, the high-temperature reducing atmosphere uses hydrogen or carbon monoxide as reducing gas.

[0022] Furthermore, the calcination temperature is 1180-1230° C., and the calcination time is 48-72 hours.

[0023] Furthermore, the semicircular hole convex piece bent inwardly on the tube wall caused by the drilling and punching mentioned above comprises: the calcined hollow iron-carbon tube is fixed by a punch press, and a blade-type drill bit is used to punch the hollow iron-carbon tube wall from the outside to the inside, cutting the tube wall and bending it inwardly to form a semicircular convex piece.

[0024] Furthermore, the inward bending angle of the semicircular convex piece is 30-45 degrees, and the diameter of the semicircular hole convex piece is 1.25-1.75 cm. Furthermore, the diameter of the semicircular hole convex piece is 1.5 cm.

[0025] The present application also provides a hollow iron-carbon filler tube prepared by the above-mentioned method for preparing a micro-electrolysis hollow iron-carbon filler tube.

[0026] The present application also provides the application of the above-mentioned hollow iron-carbon filler tube in iron-carbon micro-electrolysis to treat wastewater.

[0027] Furthermore, the above application includes setting up a plate mesh with hollow circular holes in a treatment pool or device, and vertically inserting the above hollow iron-carbon filler tube into the hollow circular holes of the plate mesh. The spacing between the circular holes is 0.5 to 1 cm, and the number of circular holes is converted according to the cross-sectional size of the treatment pool or device.

[0028] Furthermore, the diameter of the hollow circular holes in the plate mesh is 0.5 to 1 cm larger than the outer diameter of the hollow iron-carbon filler tube. Iron-carbon micro-electrolysis reactions typically occur in acidic environments. The plate mesh provides both support strength and acid corrosion resistance. The slightly larger openings in the plate mesh compared to the outer diameter of the iron-carbon filler tube facilitate loading and subsequent replacement during project implementation. This also allows air and water to flow smoothly upward through the gaps between the holes, contacting and scrubbing the outer wall of the tube, improving reaction efficiency. Maintaining a certain spacing between the holes in the plate mesh effectively prevents the filler tubes from touching each other, eliminating the risk of packing compaction caused by packing accumulation.

[0029] Furthermore, the plate mesh with hollow circular holes can be made of 316L stainless steel or acid-resistant PE or ABS plastic.

[0030] 3. Beneficial effects

[0031] Compared with the prior art, the present application has the following advantages:

[0032] (1) The present application provides a micro-electrolysis hollow iron-carbon filler tube and its preparation method and application, which is prepared by uniformly mixing ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder, adding clean water and extruding and injection molding to obtain a hollow iron-carbon tube green body, which is then sent to a high-temperature reducing atmosphere furnace for calcination, and then drilled and punched on the tube wall to create a semicircular hole convex piece bent inwardly into the tube. Ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder undergo different chemical reactions under a high-temperature reducing atmosphere. Ferroferric oxide powder and catalyst precursor powder are both metal oxides, which can be reduced to corresponding elemental metals in the range of 1180-1230°C. The oxygen atoms in the oxides are removed from the original skeleton, releasing a large number of nano-scale sponge-like channels. Carbon powder can be retained to the greatest extent under a reducing atmosphere, evenly distributed around the skeleton of elemental iron and elemental catalyst, and fully combined. Polyvinyl alcohol powder becomes sticky after combining with water, and plays a role in bonding and solidifying in the process of iron-carbon tube green body molding. It self-decomposes during high-temperature calcination, also releasing some channels, increasing The surface area of ​​the iron-carbon material is increased. At the same time, the coke powder particles remaining after high-temperature carbonization are extremely small, and will also firmly adhere to the surface or porous cavity of the iron and catalyst together with the carbon powder initially added, eventually forming an iron-carbon filler tube in which elemental iron, carbon and elemental catalyst are evenly distributed and firmly combined. After high-temperature reduction and calcination, the material ratio in the finished iron-carbon filler will change accordingly. First, the polyvinyl alcohol powder is almost completely decomposed, and the iron oxide powder and the catalyst precursor powder remove oxygen atoms to leave metal elements. The final components only include elemental iron, elemental catalyst and carbon. It has a large effective surface area, and the contact reaction efficiency of air, water and filler tube is high, which is beneficial to improving the removal effect of pollutants in wastewater.

[0033] (2) The present application provides a micro-electrolysis hollow iron-carbon filler tube and its preparation method and application, which are prepared by calcination using a high-temperature reduction method. Ferroferric oxide is reduced to elemental iron in a hydrogen or carbon monoxide reducing atmosphere. During the reduction process, sponge-like pores are formed and the toughness of the elemental iron is maintained, which facilitates punching of the formed iron-carbon tube. The catalyst precursors titanium oxide, nickel oxide or copper oxide are also reduced under a reducing atmosphere to generate elemental titanium, nickel or copper, which truly play a catalytic role. At the same time, polyvinyl alcohol is partially decomposed and carbonized during the high-temperature calcination process, and together with the pre-added carbon powder, it fully and evenly coexists with the elemental iron and the elemental catalyst, which is beneficial to improving the degradation catalytic performance of the iron-carbon filler tube.

[0034] (3) The present application provides a micro-electrolysis hollow iron-carbon filler tube and its preparation method and application, which adopts a hollow iron-carbon filler tube structure arranged with a porous mesh plate vertically inserted. When gas and water pass through the inner cavity of the hollow tube from bottom to top, the inwardly protruding semicircular convex pieces play the role of multiple gas and water mixing, so that multi-directional turbulence is formed in the tube, and turbulence can be driven to form outside the tube wall, thereby increasing the gas-liquid-solid three-phase contact efficiency, and at the same time improving the scrubbing effect of gas and water on the inner and outer walls of the tube, preventing the ferrous iron and iron hydroxide generated by the reaction from forming a passivation film on the filler surface, and avoiding the performance degradation or even failure of the filler.

[0035] (4) The present application provides a micro-electrolysis hollow iron-carbon filler tube and its preparation method and application, which is interspersed with a mesh structure of the hollow iron-carbon filler tube, so that there is a reasonable spacing between the filler tubes, avoiding the loss of point and surface reaction sites caused by the disordered accumulation of traditional fillers and the risk of filler compaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the appearance diagram of the hollow iron-carbon filler tube, where: R1: outer diameter of the filler tube; R2: inner diameter of the filler tube; R3: diameter of the punched hole in the tube wall; L: length of the filler tube; θ: inward bending angle of the punched hole filler.

[0037] Figure 2 This is the process flow for preparing hollow iron-carbon filler tubes.

[0038] Figure 3 This is a schematic diagram of the filling method of the hollow iron-carbon filler tube, where: R4: the diameter of the hole in the porous plate. DETAILED DESCRIPTION

[0039] The present application is further described below with reference to specific embodiments.

[0040] It should be noted that the terms such as "upper", "lower", "left", "right", and "middle" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of this application without substantially changing the technical content.

[0041] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0042] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0043] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement, or value. One skilled in the art can readily determine the degree of flexibility for a particular variable.

[0044] As used herein, the term "at least one of" is intended to be synonymous with "one or more of." For example, "at least one of A, B, and C" explicitly includes only A, only B, only C, and combinations of each thereof.

[0045] Concentration, amount and other numerical data can be presented in range format in this article.Should be understood that such range format is only used for convenience and brevity, and should be flexibly interpreted as not only including the numerical value clearly described as range limit, but also including all independent numerical values ​​or subranges encompassed within the scope, just as each numerical value and subrange are clearly described.For example, the numerical range of about 1 to about 4.5 should be interpreted as not only including the limit value of 1 to about 4.5 clearly described, but also including independent numerals (such as 2,3,4) and subranges (such as 1 to 3,2 to 4 etc.).The same principle is applicable to the scope of only narrating a numerical value, such as "less than about 4.5", which should be interpreted as including all above-mentioned values ​​and scopes.In addition, no matter how the breadth of described scope or feature is, this explanation should be applicable.

[0046] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0047] Example 1

[0048] This embodiment provides a micro-electrolysis hollow iron-carbon filler tube and a preparation method thereof.

[0049] The appearance of the hollow iron-carbon filler tube is as follows Figure 1 As shown, where: R1: outer diameter of the filling tube; R2: inner diameter of the filling tube; R3: diameter of the punched hole in the tube wall; L: length of the filling tube; θ: inward bending angle of the punched hole filling. Figure 2 shown.

[0050] First, ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder are uniformly mixed in a mass ratio of 90:10:3:3, wherein the carbon powder is coal-based activated carbon and the catalyst precursor powder is titanium oxide;

[0051] 8% of the total weight of the raw material powder was added with water and mixed to form a uniform wet material; then, a hollow iron-carbon tube green body with a length of 1.5 m, an outer diameter of 4 cm, and an inner diameter of 3 cm was obtained by extrusion injection molding;

[0052] The conveyor belt is sent into a high-temperature reducing hydrogen atmosphere furnace, heated to 1180℃ and kept warm for 72 hours, and then cooled after being taken out of the furnace;

[0053] Finally, a semicircular hole convex piece with a diameter of 1.5 cm and bent 45 degrees into the tube was formed on the tube wall by drilling and punching, and finally a finished micro-electrolysis hollow iron-carbon filler tube was obtained.

[0054] Example 2

[0055] This embodiment provides a micro-electrolysis hollow iron-carbon filler tube and a preparation method thereof.

[0056] First, ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder are uniformly mixed in a mass ratio of 95:10:5:3, the carbon powder is coke, and the catalyst precursor powder is copper oxide;

[0057] 10% of the total weight of the raw material powder was added with water and mixed to form a uniform wet material; then, a hollow iron-carbon tube green body with a length of 1.5 m, an outer diameter of 4 cm, and an inner diameter of 3 cm was obtained by extrusion injection molding;

[0058] The conveyor belt is sent into a high-temperature reducing hydrogen atmosphere furnace, heated to 1200℃ and kept warm for 72 hours, and then cooled after being taken out of the furnace;

[0059] Finally, a semicircular hole convex piece with a diameter of 1.5 cm and bent 45 degrees into the tube was formed on the tube wall by drilling and punching, and finally a finished micro-electrolysis hollow iron-carbon filler tube was obtained.

[0060] Example 3

[0061] This embodiment provides a micro-electrolysis hollow iron-carbon filler tube and a preparation method thereof.

[0062] First, ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder are uniformly mixed in a mass ratio of 95:15:5:0, graphite is used as the carbon powder, and no catalyst precursor powder is added;

[0063] 12% of the total weight of the raw material powder was added with clean water and stirred to form a uniform wet material; then, a hollow iron-carbon tube green body with a length of 1.5 m, an outer diameter of 4 cm, and an inner diameter of 3 cm was obtained by extrusion injection molding;

[0064] The conveyor belt is sent into a high-temperature reducing carbon monoxide atmosphere furnace, heated to 1200℃ and kept warm for 72 hours, and then cooled after being taken out of the furnace;

[0065] Finally, a semicircular hole convex piece with a diameter of 1.5 cm and bent 45 degrees into the tube was formed on the tube wall by drilling and punching, and finally a finished micro-electrolysis hollow iron-carbon filler tube was obtained.

[0066] Example 4

[0067] This embodiment provides a micro-electrolysis hollow iron-carbon filler tube and a preparation method thereof.

[0068] First, ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder are uniformly mixed in a mass ratio of 90:10:3:3, the carbon powder is coke, and the catalyst precursor powder is titanium oxide;

[0069] 8% of the total weight of the raw material powder was added with water and mixed to form a uniform wet material; then, a hollow iron-carbon tube green body with a length of 1.5 m, an outer diameter of 5 cm, and an inner diameter of 3.5 cm was obtained by extrusion injection molding;

[0070] The conveyor belt is sent into a high-temperature reducing atmosphere furnace, heated to 1230℃ and kept warm for 72 hours, and then cooled after being taken out of the furnace;

[0071] Finally, a semicircular hole convex piece with a diameter of 1.5 cm and bent 45 degrees into the tube was formed on the tube wall by drilling and punching, and finally a finished micro-electrolysis hollow iron-carbon filler tube was obtained.

[0072] Comparative Example

[0073] If the iron-carbon filler is in the shape of a regular ball with a diameter of 4 cm, the density is about 3.7 g / cm 3 , stacked in a fixed bed manner, the effective surface area per unit mass released is about 405cm 2 / kg (the contact loss between the filler particles is not counted). The hollow iron-carbon filler tube described in this application has an outer diameter of 4 cm, an inner diameter of 3 cm, a wall thickness of 0.5 cm, and a density of 3.7 g / cm 3 The effective surface area per unit mass released is about 1086 cm 2 / kg, that is, for a unit mass of iron-carbon filler, the effective surface area released by the hollow iron-carbon filler tube is about 2.7 times that of the spherical iron-carbon filler. This can be simply understood as: when filled with the same mass of filler, the reaction contact efficiency of the hollow iron-carbon filler tube is 2.7 times that of the spherical iron-carbon filler; or, under the premise of requiring the same reaction contact efficiency, the amount of hollow iron-carbon filler tube used is about 0.37 times that of the spherical iron-carbon filler.

[0074] Example 5

[0075] The hollow iron-carbon filling tubes of Examples 1-4 were used to conduct degradation experiments on organic pollutants in wastewater. Figure 3 As shown, a plate mesh (porous plate) with hollow circular holes is set up in a treatment pool or device, and the above-mentioned hollow iron-carbon filler tube is vertically inserted into the hollow circular holes of the plate mesh. The spacing between the circular holes is 0.5 to 1 cm, and the number of circular holes is converted according to the cross-sectional size of the treatment pool or device; the diameter of the hollow circular holes of the plate mesh is 0.5 to 1 cm larger than the outer diameter of the hollow iron-carbon filler tube.

[0076] To facilitate control of experimental conditions, nitrobenzene was used as the target pollutant in the water sample. A 1.5-meter-long iron-carbon tube was cut into five 30-cm lengths and placed vertically in a 2-liter beaker with an aeration tray at the bottom. 1.5 liters of nitrobenzene-based water, previously adjusted to a pH of 3.5 by adding sulfuric acid, was poured into each of the beakers described in Examples 1-4, ensuring the liquid level submerged the filler tubes. Aeration was then initiated, maintaining a consistent aeration rate. After 30 minutes of reaction, the nitrobenzene concentration in the water was measured and the nitrobenzene removal rate was calculated. The results, shown in Table 1, show that the hollow iron-carbon filler tubes prepared with the catalyst exhibited removal rates exceeding 50%.

[0077] Table 1 Micro-electrolysis reaction experimental data

[0078]

[0079] The present invention has been described in detail above with reference to specific exemplary embodiments. However, it should be understood that various modifications and variations may be made without departing from the scope of the present invention as defined by the appended claims. The detailed description and accompanying drawings should be considered merely illustrative and not restrictive, and any such modifications and variations, if any, are intended to fall within the scope of the present invention as described herein. In addition, the background art is intended to illustrate the current status and significance of the present technology and is not intended to limit the present invention or the application and areas of application of the present invention.

Claims

1. A method for preparing a micro-electrolysis hollow iron-carbon filler tube, characterized in that: The method comprises uniformly mixing ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder in proportion, adding water and extruding and injection molding to obtain a hollow iron-carbon tube green body, sending the green body into a high-temperature reducing atmosphere furnace for calcination, and then drilling and punching a tube wall to form a semicircular convex piece bent inwardly to the tube, thereby finally obtaining a micro-electrolysis hollow iron-carbon filler tube; the drilling and punching of the tube wall to form the semicircular convex piece bent inwardly comprises: punching the tube wall from the outside to the inside, cutting the tube wall and bending it inwardly to form the semicircular convex piece; The added mass ratio of the ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder is 90-95:10-15:3-5:3; The catalyst precursor powder is one or more combinations of titanium oxide, nickel oxide, and copper oxide; The calcination temperature is 1180-1230° C., and the calcination time is 48-72 h.

2. The method for preparing a micro-electrolysis hollow iron-carbon filler tube according to claim 1, characterized in that: The semicircular convex piece is symmetrically formed with two positive and negative openings at the same circumferential position of the tube wall.

3. The method for preparing a micro-electrolysis hollow iron-carbon filler tube according to claim 1 or 2, characterized in that: The inward bending angle of the semicircular protrusion is 30-45 degrees.

4. The method for preparing a micro-electrolysis hollow iron-carbon filler tube according to claim 3, characterized in that: The amount of water used is 8% to 12% of the total mass of the mixture of ferroferric oxide powder, carbon powder, polyvinyl alcohol powder and catalyst precursor powder.

5. The method for preparing a micro-electrolysis hollow iron-carbon filler tube according to claim 4, characterized in that: The carbon powder is one of coke, activated carbon and graphite.

6. The method for preparing a micro-electrolysis hollow iron-carbon filler tube according to claim 5, characterized in that: The outer diameter of the hollow iron-carbon tube green body is 4-5 cm, and the difference between the outer diameter and the inner diameter is 1-1.6 cm.

7. The method for preparing a micro-electrolysis hollow iron-carbon filler tube according to claim 6, characterized in that: The high-temperature reducing atmosphere uses hydrogen or carbon monoxide as reducing gas.

8. A hollow iron-carbon filled tube prepared by the method for preparing a micro-electrolysis hollow iron-carbon filled tube according to any one of claims 1 to 7.

9. Use of the hollow iron-carbon filler tube according to claim 8 in treating wastewater by iron-carbon micro-electrolysis, characterized in that: The application includes setting up a plate mesh with hollow circular holes in a treatment pool or device, and vertically inserting a hollow iron-carbon filler tube into the hollow circular holes of the plate mesh, with a spacing of 0.5 to 1 cm between the circular holes; the diameter of the hollow circular holes of the plate mesh is 0.5 to 1 cm larger than the outer diameter of the hollow iron-carbon filler tube.

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