Advanced oxidation treatment device for medical sewage, iron electrode and preparation method of iron electrode

Abstract

The invention relates to a medical sewage advanced oxidation treatment device, an iron electrode and a preparation method thereof, and the preparation method comprises the following steps: S1, adding zinc nitrate and ferric acetylacetonate into methanol to obtain a solution A; 2-methylimidazole is added into methyl alcohol, and a solution B is obtained; s2, rapidly pouring the solution B into the solution A, and stirring for 24 hours to obtain powder; s3, dispersing the powder in a methanol solution to obtain a solution C; s4, sequentially adding a hexadecyl trimethyl ammonium bromide solution, a sodium hydroxide solution and a tetraethoxysilane solution into the solution C to obtain a precursor solution; and S5, uniformly coating the precursor solution on the surface of an iron plate, roasting the iron plate, and washing with hydrofluoric acid to obtain the iron electrode. According to the iron electrode prepared by the invention, the electron transfer capability of the surface of the electrode can be improved by coupling the monatomic site catalytic layer on the surface of the iron electrode, so that the rate of catalytic reaction can be increased, and meanwhile, the occurrence of side reaction can be reduced, thereby indirectly protecting the internal iron electrode and slowing down the corrosion of the electrode.

Description

Technical Field

[0001] The invention belongs to the field of electrodes, in particular to an advanced oxidation treatment device for medical sewage, an iron electrode and a preparation method thereof. Background Art

[0002] Medical wastewater contains a large amount of organic residues, which are difficult to remove by traditional treatment methods. Electrocatalytic oxidation is usually used for treatment. For details, please refer to the prior art such as CN202310016399.1 Medical Wastewater Treatment Device and Method. In the electrocatalytic oxidation treatment device, multiple electrode plates are required. The electrode plates are iron plates, which are low in cost and can provide ferrous ions to produce Fenton reaction and improve the treatment effect. However, iron electrodes are prone to corrosion and need to be replaced frequently, which is inconvenient for later maintenance. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a medical sewage advanced oxidation treatment device, an iron electrode and a preparation method thereof, which can reduce the corrosion rate of the iron electrode and extend the service life.

[0004] To solve the above problems, the technical solution adopted by the present invention is: a method for preparing an iron electrode, comprising the following steps:

[0005] S1. Add zinc nitrate and ferric acetylacetonate to methanol, and mix them evenly using ultrasound to obtain solution A;

[0006] Add 2-methylimidazole to methanol and mix evenly using ultrasound to obtain solution B;

[0007] S2. Pour solution B into solution A quickly, stir for 24 hours, and then centrifuge to obtain powder, wash the powder with water and methanol for multiple times, and then vacuum dry the powder at 80°C for 12 hours;

[0008] S3, dispersing the dried powder in methanol, and adding deionized water, the volume ratio of methanol to deionized water is 1:1, to obtain solution C;

[0009] S4, adding a 25 mg / mL hexadecyltrimethylammonium bromide solution, a 6 mg / mL sodium hydroxide solution and an ethyl orthosilicate solution to solution C in sequence, and stirring for 2 hours to obtain a precursor solution; wherein the ethyl orthosilicate and methanol are mixed in a volume ratio of 1:5 to obtain the ethyl orthosilicate solution;

[0010] S5, the precursor solution obtained in step S4 is evenly coated on the surface of the iron plate, and then the iron plate is roasted in an inert atmosphere at a temperature of 900°C to generate a single atomic site catalytic layer on the surface of the iron plate; when coating, a coating is first performed, and then the iron plate is dried, and then a second coating is performed. The iron plate can be a conventional iron plate, and the surface of the iron plate is first cleaned to remove impurities and oil stains, and then coated.

[0011] S6. Rinse the single-atom site catalytic layer with 10 wt % hydrofluoric acid at 80° C. to obtain an iron electrode.

[0012] The iron electrode is prepared by the above method.

[0013] The medical wastewater advanced oxidation treatment device comprises a plurality of cathode plates and anode plates, wherein the cathode plates and anode plates are arranged alternately and there is a gap between the cathode plates and anode plates; the cathode plates and anode plates are the above-mentioned iron electrodes.

[0014] Further, it includes an electrocatalytic oxidation tank and a mud removal device;

[0015] The bottom side wall of the electrocatalytic oxidation tank is provided with a plurality of water inlet nozzles, the water outlet direction of the water inlet nozzles is perpendicular to the radial direction of the electrocatalytic oxidation tank, the water inlet nozzles are connected to a water inlet pipe, a pressure pump is provided on the water inlet pipe, and the water inlet pipe between the pressure pump and the water inlet nozzles is connected to an ozone supply mechanism;

[0016] The cathode plate and the anode plate are arranged above the water inlet nozzle;

[0017] The upper side wall of the electrocatalytic oxidation tank is provided with a water outlet, and the water outlet is connected to the mud removal equipment;

[0018] The cathode plate and the anode plate are mesh plates.

[0019] Furthermore, a circulation pipe is arranged outside the electrocatalytic oxidation tank, the upper end of the circulation pipe is connected to the electrocatalytic oxidation tank above the cathode plate and the anode plate, the lower end of the circulation pipe is connected to the electrocatalytic oxidation tank at the cathode plate and the anode plate, and the water outlet direction of the lower end of the circulation pipe is perpendicular to the radial direction of the electrocatalytic oxidation tank, and a circulation pump is arranged on the circulation pipe.

[0020] Furthermore, a first interception net is arranged below the cathode plate and the anode plate, a plurality of cleaning balls with a density less than that of water are arranged in the electrocatalytic oxidation tank above the first interception net, a second interception net is arranged at the upper end of the circulation pipe, the water outlet is connected to a separation bin, the bottom of the separation bin is connected to the mud removal equipment through a water pipe, an arc-shaped third interception net is arranged in the separation bin, one end of the third interception net is connected to an inclined delivery pipe, and the lower end of the delivery pipe is connected to the circulation pipe.

[0021] Furthermore, the cleaning ball comprises an elastic mesh shell, a ferrous silicate particle layer and a hollow floating ball which are sequentially arranged from the outside to the inside.

[0022] Furthermore, the inner wall of the electrocatalytic oxidation tank is provided with a circular lower support ring and an upper support ring, and the lower support ring is fixed to the inner wall of the electrocatalytic oxidation tank; an electrode mounting frame is provided in the electrocatalytic oxidation tank, and the electrode mounting frame includes a bottom ring plate, and a lower positioning sleeve is provided on the upper surface of the bottom ring plate, and a plurality of first slots are provided on the inner wall of the lower positioning sleeve; a plurality of vertical connecting columns are provided on the bottom ring plate, and an upper positioning sleeve is fixedly provided on the top of the connecting column, and a plurality of second slots are provided on the inner wall of the upper positioning sleeve, and the lower ends of the cathode plate and the anode plate are plugged into the first slots, and the upper ends of the cathode plate and the anode plate are plugged into the second slots; the upper support ring is detachably installed on the inner wall of the electrocatalytic oxidation tank, and a first plane bearing is provided on the lower surface of the upper support ring, and the first plane bearing presses the upper positioning sleeve; the bottom ring plate is installed on the lower support ring through the second plane bearing.

[0023] Furthermore, the mud removal equipment is a sedimentation tank, and a mud discharge mechanism is provided at the bottom of the sedimentation tank.

[0024] Furthermore, the mud removal equipment includes a flexible filter cloth and a vertically arranged filter cartridge, the bottom of the filter cartridge is sealed by a bottom plate, a vertical first cylinder and a second cylinder are arranged in the filter cartridge, the first cylinder is located inside the second cylinder, and the lower end of the first cylinder is connected to the lower end of the second cylinder through a circular support plate, the upper end of the second cylinder is connected to the upper end of the filter cartridge through a circular top plate, the upper end of the first cylinder is lower than the upper end of the second cylinder, and a detachable cover is arranged on the upper port of the second cylinder, and a water inlet cavity is formed between the first cylinder and the second cylinder, and a water inlet cavity is arranged on the cover A water inlet hole connected to the water inlet cavity is provided; through holes are provided on the first cylinder, the second cylinder and the support plate; the filter cloth includes an outer filter cartridge, a bottom horizontal section, an inner filter cartridge and a top horizontal section that are integrally formed, the outer filter cartridge covers the inner wall of the second cylinder, the bottom horizontal section covers the support plate, the inner filter cartridge covers the outer wall of the first cylinder, the top horizontal section covers the upper port of the first cylinder, the upper end edge of the outer filter cartridge is turned outward to cover the upper end surface of the second cylinder, and the upper end turn-over of the outer filter cartridge is pressed by the cover plate, and an elastic sealing pad is provided on the lower surface of the cover plate; a clean water outlet is provided on the filter cartridge.

[0025] The beneficial effect of the present invention is that the iron electrode prepared by the present invention can improve the electron transfer ability of the electrode surface by coupling a single atomic site catalytic layer on its surface, which helps to increase the rate of the catalytic reaction while reducing the occurrence of side reactions, thereby indirectly protecting the internal iron electrode and slowing down electrode corrosion.

[0026] In addition, the single-atom site catalytic layer can form a protective film on the surface of the iron electrode, preventing sewage from directly contacting the iron electrode and reducing the possibility of corrosion of the iron electrode.

[0027] In addition, due to the protection of the single-atom site catalytic layer, the chemical stability of the iron electrode can be improved, preventing the iron electrode from undergoing structural changes or dissolution under harsh working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of the surface of a conventional iron electrode;

[0029] Figure 2 is a schematic diagram of the surface of the iron electrode of the present invention;

[0030] Figure 3 It is an overall schematic diagram of the present invention;

[0031] Figure 4 is a schematic diagram of a cathode plate and an anode plate of the present invention;

[0032] Figure 5 It is a top view schematic diagram of the water inlet nozzle;

[0033] Figure 6 It is a schematic diagram of a cleaning ball;

[0034] Figure 7 It is a schematic diagram of the installation of cathode plate and anode plate;

[0035] Figure 8 yes Figure 7 Schematic cross-sectional view of AA in the figure;

[0036] Fig. 9 It is a schematic diagram of a mud removal device;

[0037] Fig.10 It is a schematic diagram of another type of mud removal equipment. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0039] The method for preparing the iron electrode of the present invention comprises the following steps:

[0040] S1. Add zinc nitrate (molecular formula Zn(NO3)2·6H2O) and ferric acetylacetonate (molecular formula Fe(acac)3) into methanol and mix them evenly using ultrasound to obtain solution A.

[0041] Add 2-methylimidazole to methanol and mix evenly using ultrasound to obtain solution B;

[0042] S2. Pour solution B into solution A quickly, stir for 24 hours, and then centrifuge to obtain powder, wash the powder with water and methanol for multiple times, and then vacuum dry the powder at 80°C for 12 hours;

[0043] S3, dispersing the dried powder in methanol, and adding deionized water, the volume ratio of methanol to deionized water is 1:1, to obtain solution C;

[0044] S4, adding 25 mg / mL hexadecyltrimethylammonium bromide solution (CTAB, solute is water), 6 mg / mL sodium hydroxide solution (NaOH, solute is water) and tetraethyl orthosilicate solution (TEOS) to solution C in sequence, and stirring for 2 hours to obtain a precursor solution; wherein tetraethyl orthosilicate and methanol are mixed in a volume ratio of 1:5 to obtain the tetraethyl orthosilicate solution;

[0045] S5, uniformly coating the precursor solution obtained in step S4 on the surface of the iron plate, and then calcining the iron plate in an inert atmosphere at a calcination temperature of 900° C. to generate a single atomic site catalytic layer on the surface of the iron plate; during coating, first coating is performed, then the iron plate is dried, and then a second coating is performed;

[0046] S6. Rinse the single-atom site catalytic layer with 10 wt % hydrofluoric acid at 80° C. to obtain an iron electrode.

[0047] Embodiment 1

[0048] The method for preparing the iron electrode of this embodiment comprises the following steps:

[0049] S1. Add 0.5 g zinc nitrate and 0.21 g ferric acetylacetonate to 24 mL methanol and mix them evenly using ultrasound to obtain solution A.

[0050] Add 1.11 g of 2-methylimidazole to 24 mL of methanol and mix well using ultrasound to obtain solution B;

[0051] S2. Pour solution B into solution A quickly, stir vigorously for 24 hours, and then centrifuge to obtain powder, wash the powder with water and methanol for multiple times, and then vacuum dry the powder at 80°C for 12 hours;

[0052] S3, dispersing the dried powder in 36 mL of methanol, and adding 36 mL of deionized water to obtain solution C;

[0053] S4, adding 1.8 mL of 25 mg / mL hexadecyltrimethylammonium bromide solution, 3 mL of 6 mg / mL sodium hydroxide solution and 72 mL of ethyl orthosilicate solution to solution C in sequence, and stirring for 2 hours to obtain a precursor solution; wherein ethyl orthosilicate and methanol are mixed in a volume ratio of 1:5 to obtain the ethyl orthosilicate solution;

[0054] S5, uniformly coating the precursor solution obtained in step S4 on the surface of the iron plate, and then calcining the iron plate in an inert atmosphere at a calcination temperature of 900° C. to generate a single atomic site catalytic layer on the surface of the iron plate; during coating, first coating is performed, then the iron plate is dried, and then a second coating is performed;

[0055] S6. Rinse the single-atom site catalytic layer with 10 wt % hydrofluoric acid at 80° C. to obtain an iron electrode.

[0056] The iron electrode of the present invention is prepared by the above method.

[0057] The medical wastewater advanced oxidation treatment device of the present invention is as follows: Figure 3 , Figure 4 and Figure 5 As shown, it includes a plurality of cathode plates 7 and anode plates 8, which are alternately arranged, and there is a gap between the cathode plates 7 and the anode plates 8; the cathode plates 7 and the anode plates 8 are iron electrodes prepared by the above-mentioned preparation method of the iron electrode. The cathode plates 7 and the anode plates 8 are respectively connected to the negative electrode and the positive electrode of the DC power supply, and can catalyze ozone after power is turned on.

[0058] It also includes an electrocatalytic oxidation tank 1 and a mud removal device 2. The electrocatalytic oxidation tank 1 adopts a circular tank body, which is vertically arranged and supported by a group of supporting legs. The upper and lower ends of the electrocatalytic oxidation tank 1 can be sealed by a head.

[0059] A plurality of water inlet nozzles 3 are arranged on the bottom side wall of the electrocatalytic oxidation tank 1, the water outlet direction of the water inlet nozzles 3 is perpendicular to the radial direction of the electrocatalytic oxidation tank 1, the water inlet nozzles 3 are connected to a water inlet pipe 4, a booster pump 5 is arranged on the water inlet pipe 4, and an ozone supply mechanism 6 is connected to the water inlet pipe 4 between the booster pump 5 and the water inlet nozzles 3.

[0060] The water inlet pipe 4 can be connected to the medical sewage collection tank to transport the medical sewage to the water inlet nozzle 3. The water inlet nozzle 3 can be a 90-degree elbow fixed on the inner wall of the electrocatalytic oxidation tank 1. The water inlet nozzle 3 can be 3, 4, etc., evenly distributed. Since the water outlet direction of the water inlet nozzle 3 is perpendicular to the radial direction of the electrocatalytic oxidation tank 1, after the medical sewage enters the electrocatalytic oxidation tank 1 from the water inlet nozzle 3, the flow direction is also perpendicular to the radial direction of the electrocatalytic oxidation tank 1, and it will flow along the circumference of the electrocatalytic oxidation tank 1, thereby forming a vortex. The booster pump 5 is used to pressurize the medical sewage and increase the flow speed of the medical sewage, so that the medical sewage enters the electrocatalytic oxidation tank 1 at a flow rate of about 10m / s, effectively forming a vortex. The ozone supply mechanism 6 is used to supply ozone, and existing ozone generators and other equipment can be used. The cathode plate 7 and the anode plate 8 are arranged above the water inlet nozzle 3.

[0061] The upper side wall of the electrocatalytic oxidation tank 1 is provided with a water outlet 9, which is connected to the mud removal device 2 and is used to transport the medical sewage after oxidation treatment to the mud removal device 2. The mud removal device 2 is used to remove solid impurities in the sewage to obtain clean water.

[0062] The conventional cathode plate 7 and anode plate 8 are usually rectangular plates without holes. When the medical sewage reaches the cathode plate 7 and anode plate 8, it can only pass through the gap between the cathode plate 7 and anode plate 8, but cannot pass through the cathode plate 7 and anode plate 8. The cathode plate 7 and anode plate 8 have a large resistance to the flow of sewage, and the sewage cannot maintain a swirling flow. The present invention changes the cathode plate 7 and anode plate 8 into a rectangular plate as shown in FIG. Figure 2 The mesh plate shown in the figure is provided with a plurality of holes on the cathode plate 7 and the anode plate 8, through which the medical sewage can pass, thereby reducing the flow resistance to the medical sewage, so that the medical sewage can maintain a swirling state, thereby ensuring that ozone can contact the cathode plate 7 and the anode plate 8 faster and more evenly, thereby generating hydroxyl radicals faster and more evenly ( · OH), while hydroxyl radicals ( · OH) can contact the organic matter and other pollutants in the sewage faster and more evenly, thus ensuring the decomposition efficiency and effect of the pollutants.

[0063] In order to further ensure that the medical sewage is in a swirling state at the cathode plate 7 and the anode plate 8, the present invention is provided with a circulation pipe 10 outside the electrocatalytic oxidation tank 1, the upper end of the circulation pipe 10 is connected to the electrocatalytic oxidation tank 1 above the cathode plate 7 and the anode plate 8, the lower end of the circulation pipe 10 is connected to the electrocatalytic oxidation tank 1 at the cathode plate 7 and the anode plate 8, and the water outlet direction of the lower end of the circulation pipe 10 is perpendicular to the radial direction of the electrocatalytic oxidation tank 1, and a circulation pump 11 is provided on the circulation pipe 10. The upper end of the circulation pipe 10 is lower than the water outlet 9, and the shape of the lower end of the circulation pipe 10 can be similar to the water inlet nozzle 3. After the circulation pump 11 is started, the water above the cathode plate 7 and the anode plate 8 can be sucked into the circulation pipe 10, and then accelerated to spray out from the lower end of the circulation pipe 10. Since the water outlet direction of the lower end of the circulation pipe 10 is perpendicular to the radial direction of the electrocatalytic oxidation tank 1, it will promote the rotation of the sewage in the electrocatalytic oxidation tank 1, that is, maintain the swirling flow of the sewage. Part of the sewage returns to the cathode plate 7 and the anode plate 8 again through the circulation pipe 10, achieving secondary treatment and ensuring the treatment effect.

[0064] During the operation of the iron electrode, iron mud is generated, and the iron mud adheres to the surface of the iron electrode. After a period of operation, it will affect the contact between ozone and the electrode, thereby affecting the electrocatalytic effect. In order to remove the iron mud on the surface of the cathode plate 7 and the anode plate 8 or other solid impurities in the sewage, the present invention is provided with a first interception net 12 below the cathode plate 7 and the anode plate 8, and a plurality of cleaning balls 13 with a density less than water are provided in the electrocatalytic oxidation tank 1 above the first interception net 12. The upper port of the circulation pipe 10 is provided with a second interception net 14, and the water outlet 9 is connected to a separation chamber 16. The bottom of the separation chamber 16 is connected to the mud removal device 2 through a water pipe 15. An arc-shaped third interception net 17 is provided in the separation chamber 16, and one end of the third interception net 17 is connected to an inclined delivery pipe 18, and the lower end of the delivery pipe 18 is connected to the circulation pipe 10.

[0065] The mesh diameters of the first interception net 12, the second interception net 14 and the third interception net 17 are smaller than the outer diameter of the cleaning ball 13. The first interception net 12 can prevent the cleaning ball 13 from moving under the first interception net 12; the second interception net 14 can prevent the cleaning ball 13 from entering the circulation pump 11 and causing blockage or damage to the circulation pump 11; the third interception net 17 can prevent the cleaning ball 13 from entering the water pipe 15, ensuring that the cleaning ball 13 can enter the electrocatalytic oxidation tank 1 through the circulation pipe 10 to achieve circulation motion. Since the density of the cleaning ball 13 is less than that of water, it will float to the surface of the sewage and be discharged from the outlet 9 to the separation chamber 16 with the sewage. After being intercepted by the third interception net 17, the cleaning ball 13 stays on the third interception net 17, then rolls along the third interception net 17 to the delivery pipe 18, and enters the circulation pipe 10 along the delivery pipe 18, and then enters the electrocatalytic oxidation tank 1 with the high-speed flowing water and moves with the water flow. When the cleaning ball 13 contacts the cathode plate 7 and the anode plate 8, it collides with the cathode plate 7 and the anode plate 8, so that the solid impurities such as iron mud on the surface of the cathode plate 7 and the anode plate 8 are separated, and the cathode plate 7 and the anode plate 8 are cleaned. As the movement speed of the cleaning ball 13 decreases, the cleaning ball 13 gradually floats to the liquid surface and enters the separation chamber 16 again to achieve circulation.

[0066] In the present invention, the cleaning ball 13 can be a lightweight elastic sphere, such as a hollow plastic ball, a rubber ball, etc., as a preferred embodiment. Figure 6 As shown, the cleaning ball 13 includes an elastic mesh shell 131, an iron silicate particle layer 132 and a hollow float 133 arranged in sequence from the outside to the inside. The elastic mesh shell 131 can be made of plastic or other materials, and the iron silicate particle layer 132 is composed of a plurality of iron silicate particles, and the particle size of the iron silicate particles is larger than the mesh diameter of the elastic mesh shell 131. The hollow float 133 can be made of a plastic ball, a rubber ball, etc. Iron silicate can also catalyze ozone, and combined with the electrocatalysis of the cathode plate 7 and the anode plate 8, it can promote ozone to produce hydroxyl radicals ( · OH), improve treatment efficiency, while increasing ozone utilization and reducing ozone waste.

[0067] The cathode plate 7 and the anode plate 8 can be fixedly mounted on the mounting frame. In order to fully and effectively clean the cathode plate 7 and the anode plate 8 and prevent impurities such as iron mud from adhering to the surface of the cathode plate 7 and the anode plate 8, as shown in FIG. Figure 7 and Figure 8As shown, the present invention is provided with an annular lower support ring 29 and an upper support ring 30 on the inner wall of the electrocatalytic oxidation tank 1, the lower support ring 29 and the upper support ring 30 are annular, and the lower support ring 29 is fixed to the inner wall of the electrocatalytic oxidation tank 1. An electrode mounting frame is provided in the electrocatalytic oxidation tank 1, and the electrode mounting frame includes an annular bottom ring plate 31, and a lower positioning sleeve 32 is provided on the upper surface of the bottom ring plate 31, and the lower positioning sleeve 32 is coaxial with the electrocatalytic oxidation tank 1, and a plurality of first slots are provided on the inner wall of the lower positioning sleeve 32. A plurality of vertical connecting columns 33 are provided on the bottom ring plate 31, and an upper positioning sleeve 34 is fixedly provided on the top of the connecting column 33, and the inner diameter of the upper positioning sleeve 34 is the same as the inner diameter of the lower positioning sleeve 32, and the upper positioning sleeve 34 is coaxial with the lower positioning sleeve 32, and the inner wall of the upper positioning sleeve 34 is provided with a plurality of second slots, and the second slots correspond to the first slots one by one. The lower ends of the cathode plate 7 and the anode plate 8 are plugged into the first slot, and the upper ends of the cathode plate 7 and the anode plate 8 are plugged into the second slot. The upper support ring 30 is detachably mounted on the inner wall of the electrocatalytic oxidation tank 1, and the lower surface of the upper support ring 30 is provided with a first plane bearing, and the first plane bearing presses the upper positioning sleeve 34; the bottom ring plate 31 is mounted on the lower support ring 29 through the second plane bearing. Since the bottom and top of the electrode mounting frame are provided with plane bearings, the rotation resistance of the electrode mounting frame is small. When the sewage is sprayed out from the circulation pipe 10 and rotates and flows, the cathode plate 7 and the anode plate 8 can be pushed to rotate around the center line of the upper positioning sleeve 34 and the lower positioning sleeve 32, so that each cathode plate 7 and the anode plate 8 pass through the vicinity of the lower port of the circulation pipe 10 in turn, and the cleaning ball 13 sprayed out of the circulation pipe 10 can evenly clean each cathode plate 7 and the anode plate 8. The cathode plate 7 and the anode plate 8 can be connected to the DC power supply through a brush to ensure that the cathode plate 7 and the anode plate 8 can be stably energized when rotating.

[0068] In the present invention, the mud removal equipment 2 can be a sedimentation tank, such as Fig. 9 As shown, solid particle impurities such as iron sludge in sewage are removed by static sedimentation. A sludge discharge mechanism 19 is provided at the bottom of the sedimentation tank. The sludge discharge mechanism 19 is used to discharge the iron sludge settled to the bottom of the sedimentation tank. A sludge pump can be used.

[0069] In addition, the mud removal equipment 2 can also adopt filtering equipment. There are many types of existing filtering equipment, but there are various problems. For example, the filter element is easy to be blocked, and the filter element needs to be replaced frequently, which is inconvenient to operate; the filtering area of ​​the filter element is small, which affects the filtering efficiency; at the same time, due to the small filtering area, after some filter holes are blocked, it is easy to cause the function of the entire filter element to be greatly affected, and the replacement frequency is high; sludge pumps and other equipment are usually used to discharge the filtered iron sludge, and the equipment cost and operating cost are high, and the discharged iron sludge needs to be dehydrated by dehydration equipment.

[0070] In order to solve these problems, the mud removal equipment 2 of the present invention is as follows Fig.10As shown, it includes a flexible filter cloth 27 and a vertically arranged filter cartridge 20, the filter cartridge 20 is a cylinder, the bottom of the filter cartridge 20 is sealed by a bottom plate, and the bottom plate can be welded to the lower end of the filter cartridge 20. A vertical first cylinder 23 and a second cylinder 24 are arranged in the filter cartridge 20, the first cylinder 23, the second cylinder 24 and the filter cartridge 20 are coaxial, the first cylinder 23 is located inside the second cylinder 24, and the lower end outer wall of the first cylinder 23 is connected to the lower end of the second cylinder 24 through a circular support plate 22. The upper end of the second cylinder 24 is connected to the upper end of the filter cartridge 20 through a circular top plate 25, the upper end of the first cylinder 23 is lower than the upper end of the second cylinder 24, and a detachable cover plate 26 is arranged at the upper end of the second cylinder 24, and the cover plate 26 can be connected to the second cylinder 24 or the top plate 25 through a set of screws. The water inlet chamber 28 is formed between the first cylinder 23 and the second cylinder 24. The cover plate 26 is provided with a water inlet hole 21 connected to the water inlet chamber 28. The water inlet hole 21 is connected to the water delivery pipe 15. The water delivery pipe 15 can be a hose. When the cover plate 26 is disassembled, the water delivery pipe 15 does not need to be removed from the cover plate 26. The inner cavity of the first cylinder 23 and the space between the second cylinder 24 and the filter cylinder 20 are the clean water chamber. The first cylinder 23, the second cylinder 24 and the support plate 22 are provided with through holes, and the through holes connect the clean water chamber and the water inlet chamber 28. The filter cloth 27 includes an outer filter cartridge, a bottom horizontal section, an inner filter cartridge and a top horizontal section which are integrally formed. The outer filter cartridge covers the inner wall of the second cylinder 24, the bottom horizontal section covers the support plate 22, the inner filter cartridge covers the outer wall of the first cylinder 23, the top horizontal section covers the upper port of the first cylinder 23, the upper edge of the outer filter cartridge is turned outward to cover the upper end surface of the second cylinder 24, and the upper end turn-up of the outer filter cartridge is pressed by the cover plate 26, and the lower surface of the cover plate 26 is provided with an elastic sealing pad, which can be a rubber pad, etc., to improve the sealing performance of the upper end turn-up of the outer filter cartridge. The filter cartridge 20 is provided with a clean water outlet for discharging the filtered clean water.

[0071] In the present invention, the sewage treated by the electrocatalytic oxidation tank 1 enters the water inlet cavity 28 through the water inlet hole 21, solid impurities such as iron mud in the sewage are intercepted by the filter cloth 27, and the clean water penetrates the filter cloth 27 and enters the clean water cavity, and then is discharged through the clean water outlet.

[0072] The filter cloth 27 of the present invention includes an outer filter cartridge, a bottom horizontal section, an inner filter cartridge and a top horizontal section which are integrally formed, and has a large overall filtering area, which can improve the filtering efficiency. In addition, due to the large filtering area, when certain parts of the filter cloth 27 are blocked, the area of ​​the unblocked part is also large enough, so that the entire filter cloth 27 can operate normally, thereby reducing the frequency of replacing the filter cloth 27. When the filter cloth 27 needs to be replaced, the cover plate 26 is opened, the entire filter cloth 27 can be taken out, and then the new filter cloth 2 is loaded into the filter cartridge 20, and then the cover plate 26 is re-covered. The filter cloth 27 itself can be used as a container for storing iron mud, and solid impurities such as iron mud stay inside the filter cloth 27. When the filter cloth 27 is replaced, the iron mud inside the filter cloth 27 can be taken out at the same time, without the need for other mud discharge equipment, simplifying the equipment structure. After the filter cloth 27 is taken out, the filter cloth 27 can be directly squeezed to dehydrate the iron mud to obtain dry iron mud, which is convenient for the later treatment of the iron mud.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an iron electrode, characterized in that: The following steps are involved: S1. Add zinc nitrate and ferric acetylacetonate to methanol, and mix them evenly using ultrasound to obtain solution A; Add 2-methylimidazole to methanol and mix evenly using ultrasound to obtain solution B; S2. Pour solution B into solution A quickly, stir for 24 hours, and then centrifuge to obtain powder, wash the powder with water and methanol for multiple times, and then vacuum dry the powder at 80°C for 12 hours; S3, dispersing the dried powder in methanol, and adding deionized water, the volume ratio of methanol to deionized water is 1:1, to obtain solution C; S4, adding a 25 mg / mL hexadecyltrimethylammonium bromide solution, a 6 mg / mL sodium hydroxide solution and an ethyl orthosilicate solution to solution C in sequence, and stirring for 2 hours to obtain a precursor solution; wherein the ethyl orthosilicate and methanol are mixed in a volume ratio of 1:5 to obtain the ethyl orthosilicate solution; S5, uniformly coating the precursor solution obtained in step S4 on the surface of the iron plate, and then calcining the iron plate in an inert atmosphere at a calcination temperature of 900° C. to generate a single atomic site catalytic layer on the surface of the iron plate; during coating, first coating is performed, then the iron plate is dried, and then a second coating is performed; S6. Rinse the precursor with 10 wt % hydrofluoric acid at 80° C. to obtain an iron electrode.

2. An iron electrode, characterized in that The method according to claim 1 is adopted to prepare the 3. A medical wastewater advanced oxidation treatment device, comprising a plurality of cathode plates (7) and anode plates (8), wherein the cathode plates (7) and anode plates (8) are alternately arranged, and there is a spacing between the cathode plates (7) and the anode plates (8); characterized in that: The cathode plate (7) and the anode plate (8) are the iron electrodes as claimed in claim 2.

4. The medical wastewater advanced oxidation treatment device according to claim 3, characterized in that: It comprises an electrocatalytic oxidation tank (1) and mud removal equipment (2); The bottom side wall of the electrocatalytic oxidation tank (1) is provided with a plurality of water inlet nozzles (3), the water outlet direction of the water inlet nozzles (3) is perpendicular to the radial direction of the electrocatalytic oxidation tank (1), the water inlet nozzles (3) are connected to a water inlet pipe (4), a booster pump (5) is provided on the water inlet pipe (4), and the water inlet pipe (4) between the booster pump (5) and the water inlet nozzles (3) is connected to an ozone supply mechanism (6); The cathode plate (7) and the anode plate (8) are arranged above the water inlet nozzle (3); The upper side wall of the electrocatalytic oxidation tank (1) is provided with a water outlet (9), and the water outlet (9) is connected to the mud removal equipment (2); The cathode plate (7) and the anode plate (8) are mesh plates.

5. The medical wastewater advanced oxidation treatment device according to claim 4, characterized in that: A circulation pipe (10) is arranged outside the electrocatalytic oxidation tank (1), the upper end of the circulation pipe (10) is connected to the electrocatalytic oxidation tank (1) above the cathode plate (7) and the anode plate (8), the lower end of the circulation pipe (10) is connected to the electrocatalytic oxidation tank (1) at the cathode plate (7) and the anode plate (8), and the water outlet direction of the lower end of the circulation pipe (10) is perpendicular to the radial direction of the electrocatalytic oxidation tank (1), and a circulation pump (11) is arranged on the circulation pipe (10).

6. The medical wastewater advanced oxidation treatment device according to claim 5, characterized in that: A first interception net (12) is arranged below the cathode plate (7) and the anode plate (8); a plurality of cleaning balls (13) having a density less than that of water are arranged in the electrocatalytic oxidation tank (1) above the first interception net (12); a second interception net (14) is arranged at the upper end of the circulation pipe (10); the water outlet (9) is connected to a separation bin (16); the bottom of the separation bin (16) is connected to the mud removal equipment (2) through a water pipe (15); an arc-shaped third interception net (17) is arranged in the separation bin (16); one end of the third interception net (17) is connected to an inclined delivery pipe (18); the lower end of the delivery pipe (18) is connected to the circulation pipe (10).

7. The medical wastewater advanced oxidation treatment device according to claim 6, characterized in that: The cleaning ball (13) comprises an elastic mesh shell (131), an iron silicate particle layer (132) and a hollow floating ball (133) which are arranged in sequence from the outside to the inside.

8. The medical wastewater advanced oxidation treatment device according to claim 6, characterized in that: The inner wall of the electrocatalytic oxidation tank (1) is provided with a circular lower support ring (29) and an upper support ring (30), and the lower support ring (29) is fixed to the inner wall of the electrocatalytic oxidation tank (1); an electrode mounting frame is provided in the electrocatalytic oxidation tank (1), and the electrode mounting frame comprises a bottom ring plate (31), the upper surface of the bottom ring plate (31) is provided with a lower positioning sleeve (32), and the inner wall of the lower positioning sleeve (32) is provided with a plurality of first slots; the bottom ring plate (31) is provided with a plurality of vertical connecting columns (33), and the top of the connecting column (33) is provided with a plurality of first slots. An upper positioning sleeve (34) is fixedly arranged on the upper part, and a plurality of second slots are arranged on the inner wall of the upper positioning sleeve (34), the lower ends of the cathode plate (7) and the anode plate (8) are inserted into the first slots, and the upper ends of the cathode plate (7) and the anode plate (8) are inserted into the second slots; the upper support ring (30) is detachably mounted on the inner wall of the electrocatalytic oxidation tank (1), and a first plane bearing is arranged on the lower surface of the upper support ring (30), and the first plane bearing presses the upper positioning sleeve (34); the bottom ring plate (31) is mounted on the lower support ring (29) through the second plane bearing.

9. The medical wastewater advanced oxidation treatment device according to claim 4, characterized in that: The mud removal equipment (2) is a sedimentation tank, and a mud discharge mechanism (19) is provided at the bottom of the sedimentation tank.

10. The medical wastewater advanced oxidation treatment device according to claim 4, characterized in that: The desilting device (2) comprises a flexible filter cloth (27) and a vertically arranged filter cartridge (20), the bottom of the filter cartridge (20) being sealed by a bottom plate, a vertical first cylinder (23) and a second cylinder (24) being arranged inside the filter cartridge (20), the first cylinder (23) being located inside the second cylinder (24), and the lower end of the first cylinder (23) being connected to the lower end of the second cylinder (24) by a circular support plate (22), the upper end of the second cylinder (24) being connected to the upper end of the filter cartridge (20) by a circular top plate (25), the upper end of the first cylinder (23) being lower than the upper end of the second cylinder (24), the upper end of the second cylinder (24) being provided with a detachable cover plate (26), and a water inlet cavity being provided between the first cylinder (23) and the second cylinder (24). (28), the cover plate (26) is provided with a water inlet hole (21) connected to the water inlet chamber (28); the first cylinder (23), the second cylinder (24) and the support plate (22) are provided with through holes; the filter cloth (27) comprises an outer filter cartridge, a bottom horizontal section, an inner filter cartridge and a top horizontal section which are integrally formed, the outer filter cartridge covers the inner wall of the second cylinder (24), the bottom horizontal section covers the support plate (22), the inner filter cartridge covers the outer wall of the first cylinder (23), the top horizontal section covers the upper port of the first cylinder (23), the upper end edge of the outer filter cartridge is turned outward to cover the upper end surface of the second cylinder (24), and the upper end turn-over of the outer filter cartridge is pressed by the cover plate (26), and the lower surface of the cover plate (26) is provided with an elastic sealing gasket; the filter cartridge (20) is provided with a clean water outlet.

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