A continuous flow fenton device based on a fixed bed like design

Abstract

This invention discloses a continuous-flow Fenton device based on a fixed-bed-like design, comprising a wastewater tank, a first water pump, a catalytic reaction module, a second water pump, and a purified water tank. The first water pump provides the water flow power, causing wastewater to flow from the wastewater tank to the catalytic reaction module, and then the second water pump transports the water treated by the catalytic reaction module to the purified water tank. The catalytic reaction module includes a module cavity and a solid catalyst module disposed inside the module cavity. The module cavity has a module replacement port for disassembling and removing the solid catalyst module from the module cavity. The solid catalyst module is made of a reverse-loaded Co3O4-Al2O3 composite catalytic material. This invention, through a detachable and replaceable catalytic reaction module and a specific reverse-loaded Co3O4-Al2O3 composite catalytic material, achieves high removal rates for both single and complex organic pollutants, with stable operation, low loss, and high recovery rate; it can effectively solve the problems of excessive waste generation and difficult catalyst recovery in traditional Fenton devices.

Description

Technical Field

[0001] This invention belongs to the field of environmental water pollution control, and specifically relates to a continuous flow Fenton device based on a quasi-fixed bed design. Background Technology

[0002] Emerging pollutants such as persistent organic pollutants (POPs), endocrine disruptors, and antibiotics are widely detected in environmental water bodies such as drinking water, surface water, and groundwater, posing potential threats to human health and the ecological environment even at extremely low concentrations. Wastewater discharge is one of the main sources of organic pollutants in the environment. Studies show that many organic pollutants are difficult to remove effectively from wastewater treatment plants using conventional water treatment processes. The high concentration of organic pollutants and complex water matrix in wastewater present significant challenges to its purification. Therefore, it is essential to develop highly efficient advanced water treatment technologies for the purification of difficult-to-remove organic pollutants in wastewater.

[0003] With the development and application of advanced wastewater treatment technologies, the Fenton process has received increasing attention. The Fenton process is an economical and efficient advanced oxidation technology. During the Fenton process, hydrogen peroxide and ferrous ions react to generate highly oxidizing hydroxyl radicals, thereby oxidizing and degrading organic pollutants in wastewater. The Fenton process can be used as a pretreatment process before biological treatment of wastewater, as well as an advanced treatment process after biological treatment, for treating wastewater containing recalcitrant organic pollutants. Due to its advantages such as strong oxidation capacity, simple equipment, easy operation, and environmentally friendly reagents, the Fenton process has been widely used in industrial wastewater treatment in industries such as papermaking, printing and dyeing, pharmaceuticals, and chemicals.

[0004] Traditional Fenton oxidation, conducted in a homogeneous system, often suffers from the following technical drawbacks: First, it has a narrow pH range, with an optimal pH of approximately 3.0. When the ambient pH exceeds 4, iron salts tend to precipitate, hindering iron circulation. Second, in actual wastewater treatment processes, long-term operation under acidic conditions not only places higher demands on equipment but also requires subsequent treatment to restore the water to neutral, generating large amounts of iron sludge and increasing treatment costs. Third, because the catalyst is oxidized in the liquid phase, it is difficult to recover and reuse. To address these issues, researchers have made a series of improvements to the traditional Fenton oxidation process in recent years, developing electro-Fenton, photo-Fenton, and ozone-Fenton oxidation devices. However, these methods generally suffer from high costs, complex processes, and high energy consumption, and are unable to effectively solve the problems of secondary pollution and catalyst recovery. The wastewater treatment industry urgently needs to develop a green, economical, and sustainable new process to replace the traditional homogeneous Fenton oxidation process. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems by providing a continuous flow Fenton device based on a fixed-bed design. By compacting the reverse-loaded Co3O4-Al2O3 composite catalyst into a solid module, a replaceable catalytic reaction module is designed. This provides efficient catalysis for a variety of pollutants while solving the problems of excessive waste and difficult catalyst recovery in traditional Fenton devices, thereby achieving green, economical and sustainable treatment of wastewater.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A continuous flow Fenton device based on a fixed-bed-like design includes a wastewater tank, a first water pump, a catalytic reaction module, a second water pump, and a purified water tank. The first water pump provides water flow power, causing wastewater to flow from the wastewater tank to the catalytic reaction module. The second water pump then transports the water treated by the catalytic reaction module to the purified water tank. The catalytic reaction module includes a module cavity and a solid catalyst module disposed inside the module cavity. The module cavity has a module replacement port for disassembling and removing the solid catalyst module from the module cavity. The solid catalyst module is made of a reverse-loaded Co3O4-Al2O3 composite catalytic material.

[0008] The water purification process of this device is as follows: Wastewater flows into the wastewater tank from the outside, and the first water pump provides the water flow power, causing the wastewater to flow from the wastewater tank to the catalytic reaction module. In the catalytic reaction module, the water comes into contact with the solid catalyst module, achieving Fenton oxidation of organic pollutants. After treatment, the wastewater flows directly into the purified water tank using the water flow power provided by the second water pump. This invention, through a detachable and replaceable catalytic reaction module and a specific reverse-loaded Co3O4-Al2O3 composite catalytic material therein, achieves high removal rates for both single and complex organic pollutants, as well as high operational stability and high recovery rates, with a recovery rate exceeding 80%. The Fenton device based on a quasi-fixed-bed design provided by this invention exhibits low catalyst material loss when treating wastewater using the reverse-loaded Co3O4-Cu(NO)2 composite catalytic material.

[0009] Furthermore, the reverse-supported Co3O4-Al2O3 composite catalytic material is prepared by the following method:

[0010] Co(OH)2 and Al2O3 were dissolved in water at a molar ratio of 2:1 and subjected to hydrothermal reaction at 100℃ for 10-14 h. The resulting solid product was washed and dried, and then calcined and reduced at 400-600℃ for 1-3 h to obtain the reverse-supported Co3O4-Al2O3 composite catalyst.

[0011] Furthermore, the added Al2O3 has a particle size of 5.00–15.00 μm.

[0012] Furthermore, the solid catalyst module is prepared by the following method: the reverse-supported Co3O4-Al2O3 composite catalyst material prepared by the above method is mixed with water to obtain a mixed solution, and the ceramic honeycomb is immersed in the mixed solution. After the solution is saturated with water, it is taken out, the channels of the ceramic honeycomb are kept open, and it is dried under inert gas protection. The above process of immersing the ceramic honeycomb in the mixed solution and drying it under inert gas protection is repeated 3 to 5 times to obtain the solid catalyst module.

[0013] Preferably, the drying temperature is 100–200°C.

[0014] Furthermore, the catalytic reaction module also includes a feed port and a sludge discharge port; the feed port is located at the top of the module cavity, and the sludge discharge port is located in the middle of the module cavity.

[0015] Furthermore, the catalytic reaction module is externally connected to a pH meter for measuring the acidity or alkalinity of the liquid inside the module cavity, a level gauge for measuring the liquid level inside the module cavity, and a suspended solids concentration meter for measuring the suspended solids content in the liquid inside the module cavity.

[0016] Furthermore, the loss per unit wastewater treated by the catalytic reaction module is 0.5–1.0 kg of reverse-loaded Co3O4-Al2O3 composite catalytic material per ton of wastewater; the wastewater has a COD of 147–265 mg / L, total phosphorus of 4.62–8.31 mg / L, and suspended solids of 47–59 mg / L.

[0017] Furthermore, when the solid catalyst module in the module cavity of the catalytic reaction module is running, the optimal pH for the water sample is 4.0 when the pH is between 3.0 and 9.0.

[0018] Furthermore, when the solid catalyst module in the module cavity of the catalytic reaction module is running, an oxidant needs to be added to the feed port, and the oxidant is PMS or H2O2.

[0019] Preferably, the oxidant is PMS, and the molar ratio of the target pollutant to PMS in the wastewater is 1:5 to 40.

[0020] Preferably, the oxidant is H2O2, and the molar ratio of the target pollutant to H2O2 in the wastewater is 1:10 to 200.

[0021] Furthermore, the level gauge indirectly measures the liquid level through the hydrostatic pressure of the "liquid column" inside the container; the pH meter and suspended solids concentration meter are monitored through real-time sampling.

[0022] Furthermore, the solid catalyst module in the aforementioned continuous flow Fenton device based on a fixed-bed design can be recycled and reused after use through a mixed acid leaching method, and can be replaced after the reaction is complete.

[0023] Preferably, the solid catalyst module is a cylinder with a height of 7.8 mm and a diameter of 7.5 mm. The module material has a wall thickness of 1 mm and a pore size of 2.5 mm. The proportion of the reverse-supported Co3O4-Al2O3 catalyst to the solid catalyst module is 20% to 40%. The catalytic effect occurs through the contact between the cylindrical surface and the water.

[0024] The beneficial effects of the Fenton device based on a fixed-bed design provided by this invention are:

[0025] (1) The Fenton device based on a fixed bed design provided by the present invention contains a reverse-loaded Co3O4-Al2O3 catalytic material that not only has a high removal rate for both single organic pollutants and composite pollutants, but also has high operational stability, high recovery rate, and a recovery rate of over 80%.

[0026] (2) The Fenton device based on a fixed bed design provided by the present invention contains a reverse-loaded Co3O4-Al2O3 catalyst material with low catalyst material loss when treating wastewater. It can effectively solve the problems of excessive waste and difficult catalyst recovery in traditional Fenton devices, thereby achieving green, economical and sustainable treatment of wastewater. Attached Figure Description

[0027] Figure 1 This is an external schematic diagram of the continuous flow Fenton device based on a fixed-bed design according to the present invention.

[0028] Figure 2 This is a perspective internal structure diagram of the continuous flow Fenton device based on a fixed-bed design according to the present invention.

[0029] The labels in the diagram have the following meanings: 1 is the sewage tank; 2 is the first water pump; 3 is the catalytic reaction module; 4 is the second water pump; 5 is the water purification tank; 6 is the feed inlet; 7 is the module replacement port; 8 is the pH meter; 9 is the level gauge; 10 is the sludge discharge outlet; 11 is the suspended solids concentration meter; 12 is the module cavity; 13 is the solid catalyst module; and 14 is the guide plate. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and medicines involved in the embodiments of the present invention are commercially available and can be obtained and used by those skilled in the art through well-known channels.

[0031] Example 1

[0032] This embodiment provides a continuous flow Fenton device based on a fixed-bed-like design, combined with... Figure 1 and Figure 2 The system includes a wastewater tank 1, a first water pump 2, a catalytic reaction module 3, a second water pump 4, and a purified water tank 5. The first water pump 2 provides water flow power, causing wastewater to flow from the wastewater tank 1 to the catalytic reaction module 3, and then the second water pump 4 transports the water treated by the catalytic reaction module 3 to the purified water tank 5. The catalytic reaction module 3 includes a module cavity 12 and a solid catalyst module 13 disposed inside the module cavity 12. The module cavity 12 has a module replacement port 7 for removing the solid catalyst module 13 from the module cavity 12. Preferably, the solid catalyst module 13 can be pulled out from the module replacement port 7. The solid catalyst module 13 is made of reverse-loaded Co3O4-Al2O3 composite catalytic material.

[0033] As an optional embodiment, the catalytic reaction module 3 further includes a feed port 6 and a sludge discharge port 10; the feed port 6 is located at the top of the module cavity 12, and the sludge discharge port 10 is located in the middle of the module cavity 12. Alternatively, the catalytic reaction module 3 is externally connected to a pH meter 8 for measuring the pH of the liquid inside the module cavity 12, a level gauge 9 for measuring the liquid level inside the module cavity 12, and a suspended solids concentration meter 11 for measuring the suspended solids content in the liquid inside the module cavity 12. Alternatively, the level gauge 9 indirectly measures the liquid level through the hydrostatic pressure of the "liquid column" inside the container; the pH meter 8 and the suspended solids concentration meter 11 are monitored through real-time sampling. Alternatively, the solid catalyst module 13 is inserted into the module cavity 12, and a guide plate 14 is provided externally to guide water flow into contact with the solid catalyst module 13.

[0034] When the solid catalyst module 13 in the module cavity 12 of the catalytic reaction module 3 is running, an oxidant needs to be added to the feed port 6. The oxidant is PMS or H2O2. Preferably, the oxidant is PMS, and the molar ratio of the target pollutant in the wastewater to PMS is 1:5 to 40. Preferably, the oxidant is H2O2, and the molar ratio of the target pollutant in the wastewater to H2O2 is 1:10 to 200.

[0035] The above-mentioned reverse-supported Co3O4-Al2O3 composite catalytic material was prepared by the following method:

[0036] Co(OH)₂ and Al₂O₃ were dissolved in water at a molar ratio of 2:1 and subjected to a hydrothermal reaction at 100°C for 10–14 h. The resulting solid product was washed and dried, then calcined and reduced at 400–600°C for 1–3 h to obtain a reverse-supported Co₃O₄-Al₂O₃ catalyst. Optionally, the Al₂O₃ particle size was 5.00–15.00 μm.

[0037] The solid catalyst module 13 is prepared by the following method: the reverse-supported Co3O4-Al2O3 composite catalyst material prepared by the above method is mixed with water to obtain a mixed solution, and the ceramic honeycomb is immersed in the mixed solution. After it is saturated with water, it is taken out, the channels of the ceramic honeycomb are kept open, and it is dried under inert gas protection. The above process of immersing the ceramic honeycomb in the mixed solution and drying it under inert gas protection is repeated 3 to 5 times to obtain the solid catalyst module 13.

[0038] Specifically, the design and manufacture of the continuous flow Fenton device based on a fixed-bed design in this embodiment includes the following steps:

[0039] First, based on the aforementioned continuous-flow Fenton device and hydrodynamic direction based on a fixed-bed design, to avoid space waste and increase effective volume, the catalytic reaction module model was refined using a porous media model based on computational fluid dynamics. Furthermore, the solid catalyst module 13 was optimized and simulated using the CFDDEM coupling method and EDEM software. The final output solid catalyst module 13 is a solid cylinder model with a column height of 7.8 mm, a circular surface diameter of 7.5 mm, a module material wall thickness of 1 mm, and a pore size of 2.5 mm. The proportion of the reverse-supported Co3O4-Al2O3 composite catalytic material to the solid catalyst module 13 is 20-40%, and in this embodiment, the proportion is 30%.

[0040] Step 2: Preparation of reverse-supported Co3O4-Al2O3 composite catalyst: Utilizing the difference in metal solubility product, the raw material particles were uniformly dispersed on the surface through ion exchange. Co(OH)2 and Al2O3 were added to deionized water (500 mL) at a molar ratio of 2:1 (Co(OH)2 2.0 mol; Al2O3 1.0 mol), where the Al2O3 particle size was 10 μm. After stirring for 10 min, the mixture was hydrothermally reacted at 100 °C for 12 h. The resulting product was washed with water and dried for later use. Subsequently, the product was further calcined and reduced at 500 °C for 2 h to obtain the reverse-supported Co3O4-Al2O3 catalyst.

[0041] Preparation of solid catalyst module 13: A mixed solution was prepared by mixing the reverse-supported Co3O4-Al2O3 composite catalyst material with water. The ceramic honeycomb was then immersed in the mixed solution and removed after saturation. The channels were then vented using an air compressor and the mixture was placed in an oven and dried at 150°C in a nitrogen atmosphere. The above operation was repeated four times to obtain solid catalyst module 13.

[0042] Step 3: Assembly of the continuous flow Fenton device.

[0043] According to the direction of water flow, the sewage tank 1 is connected in sequence to the first water pump 2, the catalytic reaction module 3, the second water pump 4, and the water purification tank 5. The top of the catalytic reaction module 3 is equipped with a feed port 6 and a module replacement port 7. The feed port 6 is used to add H2O2, and the module replacement port 7 is used to replace the solid catalyst module 13. The catalytic reaction module is equipped with a pH meter 8, a level gauge 9, and a suspended solids concentration meter 11 for real-time monitoring of the water sample treatment status. The bottom of the catalytic reaction module is equipped with a sludge discharge port 10 for discharging sludge from the bottom of the container.

[0044] Step 4: Wastewater Treatment

[0045] Wastewater flows into wastewater tank 1 from the outside, and is propelled by a first water pump 2 (a peristaltic pump) to move the wastewater from wastewater tank 1 to catalytic reaction module 3. PMS is added to the reaction chamber 12 of catalytic reaction module 3 through the top feed port 6, where the molar ratio of the target pollutant in the wastewater to PMS is 1:10. The water flows into the solid catalyst module 13 in catalytic reaction module 3, achieving Fenton oxidation of the organic pollutants. The treated wastewater is then propelled directly into the water purification tank 5 by a second water pump 4.

[0046] Comparative Example 1

[0047] The preparation method is the same as in Example 1, except that when preparing the solid catalyst module 13, the reverse-supported Co3O4-Al2O3 composite catalyst material is replaced with commercially available nano Co3O4 catalyst material (average particle size of 50 nm) to prepare a solid catalyst module 13 of the same size as in Example 1.

[0048] Comparative Example 2

[0049] The preparation method is the same as in Example 1, except that in the preparation of the solid catalyst module 13, the reverse-supported Co3O4-Al2O3 composite catalyst material is replaced with the forward-supported Co3O4-Al2O3 composite catalyst material prepared by impregnation. The specific preparation method is as follows: using a supersaturated impregnation method, the same amount of Al2O3 particles as in Example 1 are impregnated in a mixed solution of Co3O4 and nickel chloride with a concentration of 0.5 mol / L. After soaking for 8–12 hours until adsorption saturation, solid-liquid separation is performed. The particle material is air-dried at room temperature, and residual moisture is removed in an oven at 105°C. Then, it is placed in a muffle furnace and calcined at 500°C for 5 hours. After cooling to room temperature, the forward-supported Co3O4-Al2O3 composite catalyst material is obtained.

[0050] Comparative Example 3

[0051] The preparation method is the same as in Example 1, except that the solid catalyst module 13 is prepared by reverse-supported Co3O4-Cu(NO)2 composite catalyst material, that is, when preparing the composite material, the Al2O3 is changed to an equal amount of Cu(NO)2.

[0052] Comparative Example 4

[0053] The preparation method is the same as in Example 1, except that the solid catalyst module 13 is prepared by reverse-supported Co3O4-Cu(NO)2 composite catalyst material, and the molar ratio of Cu(NO)2 to Co3O4 in the reverse-supported Co3O4-Cu(NO)2 composite catalyst material is 1:2.

[0054] Comparative Example 5

[0055] The preparation method is the same as in Example 1, except that the solid catalyst module 13 is a reverse-supported Co3O4-Al2O3 composite catalyst material, and the molar ratio of Al2O3 to Co3O4 in the reverse-supported Co3O4-Al2O3 composite catalyst material is 1:2.

[0056] Comparative Example 6

[0057] The preparation method is the same as in Example 1, except that the solid catalyst module 13 is prepared by reverse-supported Co3O4-Cu(NO)2 composite catalyst material, and the molar ratio of Cu(NO)2 to Co3O4 in the reverse-supported Co3O4-Cu(NO)2 composite catalyst material is 2:3.

[0058] Comparative Example 7

[0059] The preparation method is the same as in Example 1, except that the solid catalyst module 13 is a reverse-supported Co3O4-Al2O3 composite catalyst material, and the molar ratio of Al2O3 to Co3O4 in the reverse-supported Co3O4-Al2O3 composite catalyst material is 2:3.

[0060] Test Example 1: Single Pollutant Test

[0061] 1. Testing Method

[0062] The degradation rate, stability, and recovery rate of each catalyst in Example 1 and Comparative Examples 1-7 were tested after treating 100 mL of the same volume of different types of organic wastewater for 5 min with 10 μmol PMS as the oxidant. The pH of the water sample was 4.0. The removal rate is the percentage of each pollutant removed from the treated wastewater relative to the initial wastewater. Stability S = (1 - metal ion leakage rate during catalysis) × 100%. Recovery rate represents the percentage of cobalt metal obtained from the solid catalyst module 13 after treatment by a mixed acid leaching method, relative to the original cobalt element, and is used to characterize the catalyst's recyclability.

[0063] The mixed acid leaching method is carried out according to the following steps: the pulverized module is mixed with oxalic acid-sulfuric acid mixture (molar ratio of 1:5), reacted at 90℃ for 120 min, then the liquid-solid mixture is separated by filtration, and the filter cake is washed with deionized water until neutral. After drying, the leaching residue is obtained. The main component of the leaching residue is the percentage of cobalt element in the original cobalt powder catalyst.

[0064] 2. Test Results

[0065] The test results are shown in Table 1 below. As can be seen from Table 1, the reverse-supported Co3O4-Al2O3 composite catalytic material prepared by Al2O3 and Co3O4 in the specific ratio provided in Example 1 of this application has significant advantages in terms of removal rate, stability and recovery rate compared with other similar composite materials and existing traditional nano Co3O4 catalytic materials. Compared with the catalytic material Co3O4-Cu(NO)2, it is cheaper and has better performance. The continuous flow Fenton device based on a fixed bed design provided by this invention can increase the catalyst recovery rate to more than 80%; it can greatly reduce the construction and use cost of Fenton device and is suitable for widespread use in wastewater treatment.

[0066] Table 1. Removal rate, stability, and recovery rate of the catalysts in Example 1 and Comparative Examples 1-7 for different single pollutants.

[0067]

[0068] In Table 1, ATZ represents atrazine; BPA represents bisphenol A; SMX represents sulfamethoxazole; and wastewater volume is 100 mL.

[0069] Test Example 2: Cyclic stability test of the device.

[0070] 1. Testing Method

[0071] To verify the stability of the apparatus in Example 1 and Comparative Example 2, atrazine was selected as the target pollutant for repeatability experiments. After each cycle (15 min), a water sample containing 10 μmol / L atrazine was added. After each cycle, the pollutant removal rate was tested.

[0072] 2. Test Results

[0073] During 10 consecutive processing runs, the device maintained a 99.9% removal rate of atrazine while maintaining an average stability of 96.2%, reflecting the stability of the device operation; while the average stability of the device in Comparative Example 2 was 73.0%, significantly lower than that in Example 1.

[0074] Test Example 3: Composite Pollutant Test

[0075] 1. Testing Method

[0076] The apparatus described in Example 1 was used to treat various organic pollutants abundant in wastewater. p-Nitrophenol, methylene blue, rhodamine B, and dinitrophenol were selected as mixed target pollutants, with an initial concentration of 10 μmol / L for each pollutant. The total amount of wastewater was 5 tons. The removal rate was tested.

[0077] 2. Test Results

[0078] When mixed wastewater was introduced into the continuous-flow Fenton device described in Example 1, the removal rate of various pollutants reached 99.9% within a 10-minute reaction time, demonstrating the universality of this Co3O4-Al2O3 composite catalytic material for the oxidative degradation of various organic pollutants. Example 4: Actual test of catalyst material loss in wastewater from a wastewater treatment plant.

[0079] 1. Testing Method

[0080] The catalyst consumption of each continuous flow Fenton device in Example 1 and Comparative Examples 1-7 was tested when treating a large amount of wastewater. The wastewater tested was from Xishan Environmental Energy Group, with COD of 147-265 mg / L, total phosphorus of 4.62-8.31 mg / L, suspended solids of 47-59 mg / L, and a wastewater treatment capacity of 30 tons / day. After treatment, the consumption of catalytic materials was determined using the COD concentration calculation method to characterize the treatment effect of each catalyst when treating a large amount of wastewater.

[0081] 2. Test Results

[0082] The experimental results are shown in Table 2. As can be seen from Table 2, the unit wastewater treatment loss in Example 1 is 0.8 kg of reverse-loaded Co3O4-Al2O3 composite catalyst material per ton of wastewater, which is much lower than that of forward-loaded Co3O4-Al2O3 composite catalyst material and commercially available Co3O4 material.

[0083] Table 2 Catalyst consumption of each continuous flow Fenton device in Example 1 and Comparative Examples 1-2 when treating large amounts of wastewater

[0084]

[0085]

[0086] Unless otherwise specified, the model numbers of the various devices in this embodiment of the invention are not limited; any device capable of performing the above functions is acceptable. Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the sequence numbers of the embodiments described above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the solutions. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention based on the understanding of the present invention, without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A continuous flow Fenton device based on a fixed-bed design, characterized in that, The system includes a sewage tank (1), a first water pump (2), a catalytic reaction module (3), a second water pump (4), and a water purification tank (5). The first water pump (2) provides water flow power, causing sewage to flow from the sewage tank (1) to the catalytic reaction module (3), and then the second water pump (4) transports the water treated by the catalytic reaction module (3) to the water purification tank (5). The catalytic reaction module (3) includes a module cavity (12) and a solid catalyst module (13) disposed inside the module cavity (12). The module cavity (12) is provided with a module replacement port (7) for removing the solid catalyst module (13) from the module cavity (12). The solid catalyst module (13) is made of a reverse-loaded Co3O4-Al2O3 composite catalytic material. The reverse-loaded Co3O4-Al2O3 composite catalytic material is prepared by the following method: Co(OH)2 and Al2O3 are dissolved in water at a molar ratio of 2:1, and hydrothermally reacted at 100 °C for 10-14 minutes. The obtained solid product was washed and dried with water, and then calcined and reduced at 400-600℃ for 1-3 h to obtain a reverse-supported Co3O4-Al2O3 composite catalytic material; the particle size of the Al2O3 was 5.00-15.00 μm.

2. The continuous flow Fenton device based on a quasi-fixed bed design according to claim 1, characterized in that, The solid catalyst module (13) is prepared by the following method: the prepared reverse-supported Co3O4-Al2O3 composite catalyst material is mixed with water to obtain a mixed solution, and the ceramic honeycomb is immersed in the mixed solution. After the solution is saturated with water, it is taken out and the channels of the ceramic honeycomb are kept open. It is dried under inert gas protection. The above process of immersing the ceramic honeycomb in the mixed solution and drying it under inert gas protection is repeated 3 to 5 times to obtain the solid catalyst module (13).

3. The continuous flow Fenton device based on a quasi-fixed bed design according to claim 1, characterized in that, The catalytic reaction module (3) also includes a feed port (6) and a sludge discharge port (10); the feed port (6) is located at the top of the module cavity (12), and the sludge discharge port (10) is located in the middle of the module cavity (12).

4. The continuous flow Fenton device based on a quasi-fixed bed design according to claim 1, characterized in that, The catalytic reaction module (3) is also connected to a pH meter (8) for measuring the acidity or alkalinity of the liquid in the module cavity (12), a level meter (9) for measuring the liquid level in the module cavity (12), and a suspended matter concentration meter (11) for measuring the suspended matter content in the liquid in the module cavity (12).

5. The continuous flow Fenton device based on a quasi-fixed bed design according to claim 1, characterized in that, The catalytic reaction module (3) has a unit wastewater treatment loss of 0.5 to 1.0 kg of reverse-loaded Co3O4-Al2O3 composite catalytic material per ton of wastewater; the wastewater has a COD of 147 to 265 mg / L, total phosphorus of 4.62 to 8.31 mg / L, and suspended solids of 47 to 59 mg / L.

6. The continuous flow Fenton device based on a quasi-fixed bed design according to claim 1, characterized in that, When the solid catalyst module (13) in the module cavity (12) of the catalytic reaction module (3) is running, the pH of the water sample is 3.0 to 9.

0.

7. The continuous flow Fenton device based on a quasi-fixed bed design according to claim 6, characterized in that, When the solid catalyst module (13) in the module cavity (12) of the catalytic reaction module (3) is running, the pH of the water sample is 4.

0.

8. The continuous flow Fenton device based on a quasi-fixed bed design according to claim 3, characterized in that, When the solid catalyst module (13) in the module cavity (12) of the catalytic reaction module (3) is running, an oxidant needs to be added to the feed port (6). The oxidant is PMS or H2O2.

9. The continuous flow Fenton device based on a quasi-fixed bed design according to claim 4, characterized in that, The level gauge (9) indirectly measures the liquid level by the hydrostatic pressure of the "liquid column" inside the container; the pH meter (8) and the suspended solids concentration meter (11) are monitored by real-time sampling.

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