Fenton iron sludge treatment method, sewage treatment method, and fenton treatment method

Abstract

The embodiment of the application relates to the environmental protection technical field, and discloses a Fenton iron mud treatment method, a sewage treatment method and a Fenton treatment method. First, iron mud slurry is separated from Fenton process effluent; then, polymer fibers are added to the iron mud slurry, so that the iron mud slurry is attached and aged on the polymer fibers to obtain iron mud fiber aged products, wherein the ratio of the volume of the iron mud slurry to the mass of the polymer fibers is 10-100 ml:1 g. Finally, the iron mud fiber aged products are subjected to high-temperature self-reduction carbonization at 1100 DEG C-1200 DEG C for 10 min-30 min, and the carbonized products are cooled and sieved to obtain iron-based carrier catalyst fillers. In this embodiment, the iron-based carrier catalyst fillers are loose and porous through the above-mentioned mode, have high microbial loading capacity and good organic matter adsorption effect. Therefore, the iron-based carrier catalyst fillers can be applied to sewage biological treatment processes and used as heterogeneous Fenton catalysts to be added to Fenton processes, so that the whole-process recycling of Fenton iron mud is realized.

Description

Technical Field

[0001] This application relates to the field of environmental protection technology, and in particular to a method for treating Fenton iron sludge, a wastewater treatment method, and a Fenton treatment method. Background Technology

[0002] With the rapid development of my country's national economy, the industrial sector generates a large amount of toxic and recalcitrant wastewater. Due to the presence of a large quantity of recalcitrant organic and toxic pollutants, traditional separation and conversion methods are ineffective in removing these pollutants. As national environmental protection requirements continue to tighten, traditional biological treatment processes are no longer sufficient to meet increasingly stringent discharge standards for recalcitrant organic wastewater. Therefore, various advanced oxidation processes have become the mainstream treatment method for toxic and recalcitrant wastewater, with the Fenton process being the most widely used and applied.

[0003] However, the Fenton process generates a large amount of iron salt sludge while degrading organic pollutants. At present, how to properly dispose of iron salt sludge remains a problem and has become the biggest limiting factor for the large-scale operation and promotion of the Fenton process. Summary of the Invention

[0004] In view of this, some embodiments of this application provide a method for treating Fenton iron sludge, which can convert Fenton iron sludge into iron-based carrier catalyst filler, thereby realizing the resource utilization of iron sludge.

[0005] Firstly, some embodiments of this application provide a method for treating Fenton iron sludge, including:

[0006] Iron mud slurry was separated from the effluent of the Fenton process;

[0007] Polymer fibers are added to iron mud slurry, allowing the iron mud slurry to adhere to and age on the polymer fibers, resulting in aged iron mud fiber products. The ratio of the volume of iron mud slurry to the mass of polymer fibers is 10-100 ml: 1 g.

[0008] The aged iron sludge fiber was subjected to high-temperature self-reduction carbonization at 1100℃-1200℃ for 10min-30min, and then cooled and sieved to obtain iron-based carrier catalyst filler.

[0009] In some embodiments, the aforementioned separation of iron sludge from the Fenton process effluent includes:

[0010] Add a weak alkaline material to the effluent from the Fenton process until the pH value of the effluent is adjusted to 3.5-4, so that the iron ions in the effluent are converted into iron sludge precipitate.

[0011] Add a coagulant aid to the Fenton process effluent for sedimentation and separation to remove iron sludge precipitate. The amount of coagulant aid added is 100-500 mg / 10L of Fenton process effluent.

[0012] Add a strong oxidant to the iron mud precipitate and stir evenly to obtain iron mud slurry. The amount of strong oxidant added is 100-500 mg / L of iron mud precipitate.

[0013] In some embodiments, the aforementioned weakly alkaline material includes at least one of magnesium oxide, magnesium hydroxide, or magnesium carbonate, and the iron mud precipitate includes Schiele ore.

[0014] In some embodiments, the aforementioned coagulant aid includes organic flocculants and inorganic flocculants, wherein the organic flocculant includes at least one of carrageenan, xanthan gum, or sodium carboxymethyl cellulose, and the inorganic flocculant includes diatomaceous earth.

[0015] In some embodiments, the aforementioned strong oxidizing agent includes at least one of potassium ferrate, potassium permanganate, or potassium perchlorate.

[0016] In some embodiments, during the attachment aging phase, the method further includes:

[0017] Polyester polyol and cationic starch are added to the iron mud slurry, wherein the volume ratio of polyester polyol to iron mud slurry is 1:20-50, and the mass ratio of cationic starch to iron mud slurry is 1:50-100.

[0018] In some embodiments, the aforementioned polymer fibers include at least one of polyaramid fibers, polyimide fibers, polyurethane fibers, or viscose fibers.

[0019] In some embodiments, prior to the step of high-temperature self-reducing carbonization of the aged iron sludge fiber at 1100°C-1200°C for 10-30 minutes, the method further includes:

[0020] The aged iron sludge fiber was subjected to vacuum freeze-drying for 12-24 hours.

[0021] Secondly, some embodiments of this application provide a wastewater treatment method, including:

[0022] Iron-based supported catalyst packing is added to the wastewater to be treated in order to carry out a biological wastewater treatment process, wherein the iron-based supported catalyst packing is obtained by the method described in the first aspect above.

[0023] Thirdly, some embodiments of this application provide a Fenton treatment method, which uses an iron-based supported catalyst packing as a catalyst in the Fenton process to achieve recycling, wherein the iron-based supported catalyst packing is obtained by the method described in the first aspect above.

[0024] The beneficial effects of this application's embodiments: Unlike existing technologies, the Fenton iron sludge treatment method provided in this application first separates the iron sludge slurry from the Fenton process effluent; then, polymer fibers are added to the iron sludge slurry, allowing the sludge to adhere and age on the polymer fibers, resulting in aged iron sludge fibers. The volume ratio of the iron sludge slurry to the polymer fiber mass is 10-100 ml:1 g. Finally, the aged iron sludge fibers are subjected to high-temperature self-reduction carbonization at 1100℃-1200℃ for 10-30 minutes. After carbonization, the material is cooled and sieved to obtain an iron-based carrier catalyst filler. In this embodiment, the polymer fibers provide adhesion sites for the iron sludge slurry. Under oxygen-free conditions, the polymer fibers can release carbon monoxide (CO) gas, which can decompose the Fe in the iron sludge slurry. 3+ The self-reduction to zero-valent iron and the carbonization of polymer fibers, followed by the formation of a carbon skeleton by the residue, result in a porous and loose iron-based supported catalyst packing material. This material exhibits high microbial loading and good organic matter adsorption. Furthermore, the iron-catalyzed enzymes in the iron-based supported catalyst packing material enhance microbial activity and promote pollutant degradation. Therefore, this iron-based supported catalyst packing material can be applied to wastewater biological treatment processes and recycled as a heterogeneous Fenton catalyst in the Fenton process, achieving full-process recycling of Fenton iron sludge. Attached Figure Description

[0025] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0026] Figure 1 This is a flowchart illustrating the treatment method of Fenton iron sludge in some embodiments of this application;

[0027] Figure 2 This is a flowchart illustrating the treatment method of Fenton iron sludge in some other embodiments of this application. Detailed Implementation

[0028] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0030] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. In addition, the terms "first," "second," and "third" used herein do not limit the data or execution order, but only distinguish identical or similar items with essentially the same function and effect.

[0031] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0032] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0033] To better understand this application, before introducing the treatment method of Fenton iron sludge in this application, we will first introduce the Fenton process. The Fenton process utilizes Fe under acidic conditions... 2+ The Fenton process catalyzes the generation of highly oxidizing hydroxyl radicals (·OH) from H₂O₂, oxidizing recalcitrant components in wastewater into CO₂ and H₂O₂, thus effectively removing these components. Compared to other oxidation processes, the Fenton process is the most widely used due to its advantages such as good treatment effect, operation at normal temperature and pressure, and simple process flow. The effluent after Fenton treatment is generally adjusted to neutral or weakly alkaline by adding alkali, and a certain amount of flocculant is added to cause iron to precipitate as ferric hydroxide, followed by filtration to obtain Fenton iron sludge.

[0034] Fenton iron sludge contains a large number of microorganisms, various metal ions, and organic pollutants. Treating Fenton iron sludge as waste is not only a waste of resources but also causes serious secondary pollution to the environment. Therefore, the resource utilization of Fenton iron sludge is an urgent problem to be solved.

[0035] In some known methods for the resource utilization of Fenton iron sludge, sulfuric acid is added to the sludge to convert Fe(OH)3 into Fe2(SO4)3. The Fe2(SO4)3 treatment solution is then diluted with water and placed in the anode chamber of a diaphragm electrolytic cell. The organic matter in the Fenton iron sludge is first oxidized, then pumped into the cathode chamber of the diaphragm electrolytic cell for electroreduction. Concentration and crystallization are then performed under inert gas protection to obtain industrial-grade ferrous sulfate. However, this method results in incomplete degradation of the organic matter in the Fenton iron sludge, complex process parameter control, and difficulty in guaranteeing the quality of the ferrous sulfate product.

[0036] To address the aforementioned problems, this application provides a method for treating Fenton iron sludge in several embodiments. First, iron sludge slurry is separated from the Fenton process effluent. Then, polymer fibers are added to the iron sludge slurry, allowing the sludge to adhere and age on the polymer fibers, resulting in aged iron sludge fiber material. The volume ratio of the iron sludge slurry to the polymer fiber mass is 10-100 ml:1 g. Finally, the aged iron sludge fiber material is subjected to high-temperature self-reduction carbonization at 1100℃-1200℃ for 10-30 minutes. After carbonization, it is cooled and sieved to obtain an iron-based carrier catalyst filler. In this embodiment, the polymer fibers provide adhesion sites for the iron sludge slurry. Under oxygen-free conditions, the polymer fibers can release carbon monoxide (CO) gas, which can decompose the Fe in the iron sludge slurry. 3+ The self-reduction to zero-valent iron and the carbonization of polymer fibers, followed by the formation of a carbon skeleton from the residue, result in a porous and loose iron-based supported catalyst packing material. This material exhibits high microbial loading and good organic matter adsorption. Furthermore, the iron-catalyzed enzymes in the iron-based supported catalyst packing material enhance microbial activity and promote pollutant degradation. Therefore, this iron-based supported catalyst packing material can be applied to wastewater biological treatment processes and used as a heterogeneous Fenton catalyst in the Fenton process for recycling, achieving full-process recycling of Fenton iron sludge.

[0037] The following describes some embodiments of the Fenton iron sludge treatment methods provided in this application. Please refer to [link / reference]. Figure 1 The method S100 includes, but is not limited to, the following steps:

[0038] S10: Iron mud slurry is separated from the effluent of the Fenton process.

[0039] Fenton process effluent refers to the wastewater discharged after treatment using the Fenton process. It contains a large amount of iron ions, microorganisms, various metal ions, and organic pollutants. Here, the iron sludge is specifically Fenton iron sludge. The iron ions in the Fenton process effluent are converted into precipitates containing iron ions. These precipitates, along with the solid matter in the Fenton process effluent, are filtered and separated to obtain the iron sludge. Therefore, the iron sludge contains precipitates containing iron ions, microorganisms, various metal ions, and organic pollutants.

[0040] For example, strong alkaline substances such as sodium hydroxide or calcium hydroxide are added to the effluent of the Fenton process, causing iron ions to precipitate in the form of ferric hydroxide, and then the effluent is filtered to obtain iron sludge.

[0041] In some embodiments, the aforementioned step S10 specifically includes:

[0042] S11: Add a weak alkaline material to the Fenton process effluent until the pH value of the Fenton process effluent is adjusted to 3.5-4, so that the iron ions in the Fenton wastewater are converted into iron sludge precipitate.

[0043] In this embodiment, a weakly alkaline material is used to adjust the pH value of the Fenton process effluent. For example, a certain amount of weakly alkaline material is added to a certain amount of Fenton process effluent at a certain frequency, while the pH value is measured until the pH value of the Fenton process effluent is between 3.5 and 4.

[0044] In some embodiments, the weakly basic material includes at least one of magnesium oxide, magnesium hydroxide, or magnesium carbonate. It is understood that the pH adjustment process using weakly basic materials is milder and the pH is easier to control compared to strongly basic substances such as sodium hydroxide and calcium hydroxide. Furthermore, the inclusion of magnesium ions in the weakly basic material is beneficial for improving the stability of subsequent products.

[0045] Instead of adjusting the pH to 7.0-9.0, in this embodiment, setting the pH of the Fenton process effluent to 3.5-4 is sufficient to allow Fe... 3+ Complete precipitation reduces the amount of alkali needed, effectively lowering reagent dosage costs. Furthermore, when the pH is within the range of 3.5-4, iron ions are released as Fe8O8(OH)2 from Schieleite. 4.10 (SO4) 1.95 Its existence in this form is conducive to the subsequent resource utilization of iron sludge.

[0046] S12: Add coagulant aid to the Fenton process effluent for sedimentation and separation to separate iron sludge precipitate. The amount of coagulant aid added is 100-500 mg / 10 L of Fenton process effluent.

[0047] To accelerate iron ion precipitation, a coagulant aid is added to the Fenton process effluent, causing the iron sludge precipitate generated in step S11 to quickly coagulate and settle. The precipitate is then separated by settling to obtain the iron sludge precipitate.

[0048] In this embodiment, 10L of iron ion precipitate is obtained by sedimentation and concentration of 10L of Fenton process effluent. 100-500mg of coagulant is added accordingly, which can accelerate the flocculation and precipitation of iron ion precipitate and improve the efficiency of separating Fenton iron sludge.

[0049] In some embodiments, the coagulant aid includes organic flocculants and inorganic flocculants, wherein the organic flocculant includes at least one of carrageenan, xanthan gum or sodium carboxymethyl cellulose, and the inorganic flocculant includes diatomaceous earth.

[0050] Understandably, these organic flocculants have good biocompatibility and safety, have little impact on the properties of iron sludge precipitates, and will not adversely affect the subsequent use of the iron-based carrier catalyst filler as a microbial carrier filler.

[0051] Inorganic flocculants can act as coagulation nuclei to accelerate sedimentation. Furthermore, diatomaceous earth has a porous structure, which increases the specific surface area of ​​the resulting iron-based supported catalyst packing, facilitating the adsorption of microorganisms during wastewater treatment and enhancing its purification capacity.

[0052] S13: Add a strong oxidant to the iron mud precipitate and stir evenly to obtain iron mud slurry. The amount of strong oxidant added is 100-500 mg / L of iron mud precipitate.

[0053] Understandably, strong oxidants have oxidizing properties, which can break down and disperse the separated iron sludge precipitate, removing organic matter and eliminating its odor. Adding 100-500mg of strong oxidant per 1L of iron sludge precipitate is sufficient to ensure uniform dispersion and eliminate organic matter and odor.

[0054] In some embodiments, the strong oxidant includes at least one of potassium ferrate, potassium permanganate, or potassium perchlorate.

[0055] These strong oxidants not only achieve the aforementioned effects of uniformly dispersing iron sludge precipitates and eliminating organic matter and odor, but also include iron, manganese, and potassium metal ions. The addition of these metal ions can further enhance the activity of the iron-based catalyst support material obtained from subsequent treatment.

[0056] It is evident that the iron mud slurry obtained by oxidizing iron mud precipitate with a strong oxidant eliminates organic matter and odor, and is more dispersed in morphology, which is conducive to complete oxidation under high temperature conditions and improves the quality of the iron-based carrier catalyst packing obtained by oxidation.

[0057] S20: Add polymer fibers to the iron mud slurry, so that the iron mud slurry adheres to the polymer fibers and ages, to obtain aged iron mud fiber, wherein the ratio of the volume of the iron mud slurry to the mass of the polymer fibers is 10-100 ml: 1 g.

[0058] The polymer fibers have a certain length and an aspect ratio that matches the fiber morphology, thus providing adhesion sites for the iron mud slurry. The iron mud slurry adheres to and ages on the polymer fibers, resulting in aged iron mud fiber products.

[0059] The ratio of iron mud slurry volume to polymer fiber mass is 10-100 ml: 1 g. That is, 1 g of polymer fiber corresponds to 10-100 ml of iron mud slurry, which allows the iron mud slurry to fully adhere and age on the polymer fiber, resulting in aged iron mud fiber.

[0060] In some embodiments, the polymer fiber includes at least one of polyaramid fiber, polyimide fiber, polyurethane fiber, or viscose fiber. Exemplarily, the polymer fiber includes polyaramid fiber and viscose fiber, or the polymer fiber includes polyimide fiber and polyurethane fiber, etc.

[0061] In some embodiments, during the attachment aging stage, the method S100 further includes:

[0062] S21: Add polyester polyol and cationic starch to the iron mud slurry, wherein the volume ratio of polyester polyol to iron mud slurry is 1:20-50, and the mass ratio of cationic starch to iron mud slurry is 1:50-100.

[0063] In this embodiment, a certain amount of polyester polyol and cationic starch can be added to the iron slurry simultaneously with the addition of polymer fibers. The volume ratio of polyester polyol to iron slurry is 1:20-50, for example, 1:20, 1:50, or 1:25. The mass ratio of cationic starch to iron slurry is 1:50-100, for example, 1:50, 1:100, or 1:75.

[0064] In this embodiment, polyester polyol, acting as a dispersant, improves the uniformity of the iron mud slurry, while cationic starch increases the viscosity of the iron mud slurry, thereby enhancing the adhesion between the iron mud slurry and the fiber polymer. This allows the iron mud slurry to adhere uniformly and firmly to the surface of the polymer fibers, resulting in an aged iron mud fiber product that is uniform and exhibits strong iron mud adhesion.

[0065] S30: The aged iron sludge fiber is subjected to high-temperature self-reduction carbonization at 1100℃-1200℃ for 10min-30min, and then cooled and screened to obtain iron-based support catalyst filler.

[0066] For example, aged iron sludge fibers are placed in a muffle furnace, and the heating temperature is set to 1100℃-1200℃ for 10-30 minutes. The aged iron sludge fibers are carbonized at high temperature (1100℃-1200℃) for 10-30 minutes. During this process, the polymer fibers release carbon monoxide (CO) gas under oxygen-free conditions. This CO gas can oxidize the Fe in the iron sludge. 3+The iron-based catalyst packing material is porous and has a high microbial loading capacity and good organic matter adsorption effect. It is reduced to zero-valent iron and the residue after the polymer fiber is carbonized forms a carbon skeleton.

[0067] Furthermore, the iron-based supported catalyst packing can enhance microbial activity and promote pollutant degradation by promoting the enzymatic activity of microorganisms. Therefore, this iron-based supported catalyst packing can be applied to wastewater biological treatment processes and used as a heterogeneous Fenton catalyst in the Fenton process for recycling, achieving full-process recycling of Fenton iron sludge.

[0068] In some embodiments, prior to the aforementioned step S30, the method S100 further includes:

[0069] S40: Vacuum freeze-dry the aged iron mud fiber for 12-24 hours.

[0070] Before high-temperature carbonization and reduction, the aged iron mud fiber is vacuum freeze-dried for 12-24 hours. This gives the dried iron mud fiber aged material a porous structure, which is beneficial for the subsequent carbonization and reduction reaction to proceed fully, thus increasing the Fe content in the iron mud slurry. 3+ Being fully reduced to zero-valent iron is beneficial to improving the quality of iron-based catalyst packings.

[0071] Please see Figure 2 Another embodiment of this application also provides a method for treating Fenton iron sludge, wherein method S200 includes, but is not limited to, the following steps:

[0072] S210: Add a weak alkaline material to the Fenton process effluent until the pH value of the Fenton process effluent is adjusted to 3.5-4, so that the iron ions in the Fenton wastewater are converted into iron sludge precipitate.

[0073] It is understood that step S210 can be referred to in the description of step S11 above, and will not be repeated here.

[0074] S220: Add coagulant aid to Fenton process effluent for sedimentation and separation to separate iron sludge precipitate. Add strong oxidant to iron sludge precipitate and stir evenly to obtain iron sludge slurry. The amount of coagulant aid added is 100-500 mg / 10L Fenton process effluent, and the amount of strong oxidant added is 100-500 mg / 1L iron sludge precipitate.

[0075] It is understood that step S220 can be referred to in the description of steps S12 and S13 above, and will not be repeated here.

[0076] S230: Polymer fibers, polyester polyols, and cationic starch are added to the iron mud slurry, so that the iron mud slurry adheres to the polymer fibers and ages, resulting in aged iron mud fibers. The volume ratio of iron mud slurry to polymer fiber mass is 10-100 ml: 1 g, the volume ratio of polyester polyol to iron mud slurry is 1:20-50, and the mass ratio of cationic starch to iron mud slurry is 1:50-100.

[0077] It is understood that step S230 can refer to the description of steps S20 and S21 above, and will not be repeated here.

[0078] S240: The aged iron sludge fiber is first subjected to vacuum freeze-drying for 12-24 hours, and then subjected to high-temperature self-reduction carbonization at 1100℃-1200℃ for 10-30 minutes. After carbonization, it is cooled and sieved to obtain the iron-based support catalyst filler.

[0079] It is understandable that step S240 can refer to the description of steps S30 and S40 above, and will not be repeated here.

[0080] In summary, the Fenton iron sludge treatment method provided in this application first separates the iron sludge slurry from the Fenton process effluent; then, polymer fibers are added to the iron sludge slurry, allowing the sludge to adhere and age on the polymer fibers, resulting in aged iron sludge fibers. The volume ratio of the iron sludge slurry to the mass of the polymer fibers is 10-100 ml: 1 g. Finally, the aged iron sludge fibers are subjected to high-temperature self-reduction carbonization at 1100℃-1200℃ for 10-30 minutes. After carbonization, the materials are cooled and sieved to obtain an iron-based carrier catalyst filler. In this embodiment, the polymer fibers provide adhesion sites for the iron sludge slurry. Under oxygen-free conditions, the polymer fibers can release carbon monoxide (CO) gas, which can decompose the Fe in the iron sludge slurry. 3+ The self-reduction to zero-valent iron and the carbonization of polymer fibers, followed by the formation of a carbon skeleton from the residue, result in a porous and loose iron-based supported catalyst packing material. This material exhibits high microbial loading and good organic matter adsorption. Furthermore, the iron-catalyzed enzymes in the iron-based supported catalyst packing material enhance microbial activity and promote pollutant degradation. Therefore, this iron-based supported catalyst packing material can be applied to wastewater biological treatment processes and used as a heterogeneous Fenton catalyst in the Fenton process for recycling, achieving full-process recycling of Fenton iron sludge.

[0081] Some embodiments of this application also provide a wastewater treatment method, which applies the iron-based supported catalyst packing material from any of the above embodiments to a wastewater biological treatment process. Exemplarily, an iron-based supported catalyst packing material is added to the wastewater to be treated, and then a wastewater biological treatment process is carried out to remove microorganisms or organic matter from the wastewater. The wastewater biological treatment process can be a conventional technique in the art, including but not limited to aeration reaction, circulating filtration, etc., which will not be described in detail here.

[0082] The aforementioned iron-based carrier catalyst packing has a porous structure, which can improve the microbial loading effect and increase the microbial load. The iron-based carrier catalyst packing can enhance microbial activity and promote pollutant degradation. The iron-based carrier catalyst packing can also simultaneously adsorb organic matter, thereby improving the treatment effect of wastewater biological treatment process.

[0083] Some embodiments of this application also provide a Fenton treatment method, in which the iron-based supported catalyst packing from any of the above embodiments is applied to the Fenton treatment process. Specifically, the iron-based supported catalyst packing is used as the catalyst in the Fenton process, thereby enabling recycling.

[0084] For example, the pH of the industrial wastewater to be treated is adjusted, for example, to a pH of about 3.0, iron-based carrier catalyst packing is added, and aeration and oxidation reactions are carried out. Then, sedimentation and filtration are performed to remove organic matter from the industrial wastewater.

[0085] In this embodiment, the iron-based supported catalyst packing is recycled as a heterogeneous Fenton catalyst and added to the Fenton process to achieve full-process recycling of Fenton iron sludge.

[0086] To further illustrate the technical solution of this application, the following examples and comparative examples of the treatment method for Fenton iron sludge are provided for verification.

[0087] Example 1

[0088] The Fenton iron sludge was processed according to the following steps to obtain an iron-based supported catalyst packing.

[0089] (1) Take 10L of Fenton process effluent and add 1g of magnesium oxide (a weakly alkaline material) to adjust the pH of the Fenton process effluent to about 3.7, thereby reducing the Fe content in the Fenton process effluent. 3+ It transforms into iron sludge precipitate;

[0090] (2) Add 2g of coagulant (1g of carrageenan and 1g of diatomaceous earth) to precipitate and concentrate the iron mud precipitate, and separate it to obtain 1L of iron mud precipitate. After separation, add 1g of potassium ferrate (strong oxidant) and stir quickly to obtain a uniform iron mud slurry.

[0091] (3) Add 10g of polyaramid fiber (polymer fiber) to 1L of iron mud slurry, and add 20ml of polyester polyol and 2g of cationic starch to allow the iron mud slurry to adhere and age on the polymer fiber to obtain iron mud fiber aged product.

[0092] (4) The aged iron mud fiber was first vacuum freeze-dried for 24 hours. After drying, it was self-reduced carbonized at 1150℃ in a muffle furnace for 20 minutes. After carbonization, it was cooled and screened to obtain the iron-based carrier catalyst filler.

[0093] Example 2

[0094] The Fenton iron sludge was processed according to the following steps to obtain an iron-based supported catalyst packing.

[0095] (1) Take 10L of Fenton process effluent and add 1g of magnesium hydroxide (a weakly alkaline material) to adjust the pH of the Fenton process effluent to about 3.7, thereby reducing the Fe in the Fenton process effluent. 3+ It transforms into iron sludge precipitate;

[0096] (2) Add 2g of coagulant (1g xanthan gum and 1g diatomaceous earth) to precipitate and concentrate the iron mud precipitate, and separate it to obtain 1L of iron mud precipitate. After separation, add 1g of potassium permanganate (strong oxidant) and stir quickly to obtain a uniform iron mud slurry.

[0097] (3) Add 10g of polyimide fiber (polymer fiber) to 1L of iron mud slurry, and add 20ml of polyester polyol and 2g of cationic starch to allow the iron mud slurry to adhere and age on the fiber polymer to obtain iron mud fiber aged product.

[0098] (4) The aged iron mud fiber was first vacuum freeze-dried for 24 hours. After drying, it was self-reduced carbonized at 1150℃ in a muffle furnace for 20 minutes. After carbonization, it was cooled and screened to obtain the iron-based carrier catalyst filler.

[0099] Example 3

[0100] The Fenton iron sludge was processed according to the following steps to obtain an iron-based supported catalyst packing.

[0101] (1) Take 10L of Fenton process effluent and add 1g of magnesium carbonate (a weakly alkaline material) to adjust the pH of the Fenton process effluent to about 3.7, thereby reducing the Fe in the Fenton process effluent. 3+ It transforms into iron sludge precipitate;

[0102] (2) Add 2g of coagulant (1g of sodium carboxymethyl cellulose and 1g of diatomaceous earth) to precipitate and concentrate the iron mud precipitate, and separate it to obtain 1L of iron mud precipitate. After separation, add 1g of potassium perchlorate (strong oxidant) and stir quickly to obtain a homogeneous iron mud slurry.

[0103] (3) Add 10g of polyurethane fiber (polymer fiber) to 1L of iron mud slurry, and add 20ml of polyester polyol and 2g of cationic starch to allow the iron mud slurry to adhere and age on the fiber polymer to obtain iron mud fiber aged product.

[0104] (4) The aged iron mud fiber was first vacuum freeze-dried for 24 hours. After drying, it was self-reduced carbonized at 1150℃ in a muffle furnace for 20 minutes. After carbonization, it was cooled and screened to obtain the iron-based carrier catalyst filler.

[0105] Example 4

[0106] The Fenton iron sludge was processed according to the following steps to obtain an iron-based supported catalyst packing.

[0107] (1) Take 10L of Fenton process effluent, add 1g of magnesium oxide (weakly alkaline material) to adjust the pH of the Fenton process effluent to about 3.7, and reduce the Fe in the Fenton process effluent. 3+ It transforms into iron sludge precipitate;

[0108] (2) Add 2g of coagulant (1g of carrageenan and 1g of diatomaceous earth) to precipitate and concentrate the iron mud precipitate, and separate it to obtain 1L of iron mud precipitate. After separation, add 1g of potassium ferrate (strong oxidant) and stir quickly to obtain a uniform iron mud slurry.

[0109] (3) Add 10g of viscose fiber (polymer fiber) to 1L of iron mud slurry, and add 20ml of polyester polyol and 2g of cationic starch to allow the iron mud slurry to adhere and age on the fiber polymer to obtain iron mud fiber aged product.

[0110] (4) The aged iron mud fiber was first vacuum freeze-dried for 24 hours. After drying, it was self-reduced carbonized at 1150℃ in a muffle furnace for 20 minutes. After carbonization, it was cooled and screened to obtain the iron-based carrier catalyst filler.

[0111] Example 5

[0112] The Fenton iron sludge was processed according to the following steps to obtain an iron-based supported catalyst packing.

[0113] (1) Take 10L of Fenton process effluent, add 2g of magnesium oxide (weakly alkaline material) to adjust the pH of the Fenton process effluent to about 8.0, and reduce the Fe in the Fenton process effluent. 3+ It transforms into iron sludge precipitate;

[0114] (2) Add 0.5g of coagulant (0.25g of carrageenan and 0.25g of diatomaceous earth) to precipitate and concentrate the iron mud precipitate, and separate it to obtain 1L of iron mud precipitate. After separation, add 0.5g of potassium ferrate (strong oxidant) and stir quickly to obtain a uniform iron mud slurry.

[0115] (3) Add 5g of polyaramid fiber (polymer fiber) to 1L of iron mud slurry, and add 10ml of polyester polyol and 1g of cationic starch to allow the iron mud slurry to adhere and age on the polymer fiber to obtain iron mud fiber aged product.

[0116] (4) The aged iron mud fiber was first subjected to vacuum freeze drying for 8 hours. After drying, it was subjected to high-temperature self-reduction carbonization at 900℃ in a muffle furnace for 5 minutes. After carbonization, it was cooled and screened to obtain iron-based carrier catalyst filler.

[0117] Comparative Example 1

[0118] The Fenton iron sludge was processed according to the following steps to obtain an iron-based supported catalyst packing.

[0119] (1) Take 10L of Fenton process effluent, add sodium hydroxide to adjust the pH value of the Fenton process effluent to about 8.0, and remove the Fe produced by the Fenton process. 3+ It transforms into iron sludge precipitate;

[0120] (2) Add conventional coagulant polyacrylamide (PAM) to precipitate and concentrate the iron mud precipitate, and separate the iron mud precipitate.

[0121] (3) The iron mud precipitate was dried by blowing air. After drying, it was carbonized at 1150℃ for 20 minutes in a muffle furnace. After carbonization, it was cooled and screened to obtain the iron-based carrier catalyst filler.

[0122] The iron-based supported catalyst packings obtained in Examples 1-5 and Comparative Example 1 were applied to the biochemical treatment process of wastewater, and the chemical oxygen demand (COD) of the wastewater before and after biochemical treatment was tested.

[0123] Specifically, six 1L samples of wastewater containing activated sludge were taken from the aerobic tank of an industrial wastewater treatment plant. The COD of this wastewater was approximately 300 mg / L. First, the influent COD (i.e., COD before biological treatment) was tested. Then, 10g of the iron-based carrier catalyst packing obtained in Examples 1-5 and Comparative Example 1 were added to each sample. The dissolved oxygen was controlled at approximately 2.0 mg / L during aeration. The influent was circulated for 7 days. After the iron-based carrier catalyst packing had completed biofilm formation, the effluent COD (i.e., COD after biological treatment) of the different examples and comparative examples was tested. The influent COD and effluent COD reflect the removal effect of the iron-based carrier catalyst packing on microorganisms. The test results are shown in Table 1.

[0124] Table 1

[0125]

[0126] The iron-based supported catalyst packings obtained in Examples 1-5 and Comparative Example 1 were applied to the Fenton process, and the chemical oxygen demand (COD) of the wastewater before and after Fenton treatment was tested.

[0127] Specifically, six 1L samples of recalcitrant wastewater (with a COD of approximately 200 mg / L) were collected from the sedimentation tank of an industrial wastewater treatment plant. First, the influent COD (i.e., COD before Fenton treatment) was tested. Then, the pH of the wastewater was adjusted to approximately 3.0, and 5g of the carrier catalyst packing prepared in Examples 1-5 and Comparative Example 1 were added to each sample. After aeration for 30 minutes, the mixture was allowed to settle for 30 minutes. The pH of the supernatant was then adjusted to approximately 8.0, and the supernatant was filtered out. The effluent COD (i.e., COD of the supernatant after Fenton treatment) from different examples and comparative examples was tested, and the results are shown in Table 2.

[0128] Table 2

[0129]

[0130] As shown in Table 1 above, compared to Comparative Example 1, the iron-based carrier catalyst packing materials in Examples 1-5 exhibited higher microbial removal rates when applied to wastewater biochemical treatment. It can be understood that the microbial removal rate is calculated as (influent COD - effluent COD) / influent COD.

[0131] As can be seen from Table 2 above, compared with Comparative Example 1, when the iron-based supported catalyst packings in Examples 1-5 are applied to the Fenton process, the microbial removal rate corresponding to Examples 1-5 is higher.

[0132] In Examples 1-5, a weakly alkaline material was used to adjust the pH of the Fenton process effluent to 3.5-4. Compared to traditional sodium hydroxide-based pH adjustment, the reaction is milder with this weakly alkaline material, and the magnesium in the material improves the stability of subsequent products. Simultaneously, at pH 3.7, the iron sludge precipitate is composed of Schönbrunneus Fe8O8(OH)2. 4.10 (SO4) 1.95 The presence of this form makes the subsequent carbonization products more reactive.

[0133] In Examples 1-5, the coagulant aids included organic and inorganic flocculants. The selected organic flocculants exhibited good biocompatibility and safety, had minimal impact on the properties of the iron sludge precipitate, and would not adversely affect the use of the obtained iron sludge carrier catalyst packing as a microbial carrier packing. The inorganic flocculant, diatomaceous earth, could act as coagulation nuclei to accelerate sedimentation. Furthermore, diatomaceous earth has a porous structure, which can increase the specific surface area of ​​the obtained iron sludge carrier catalyst packing and improve its adsorption performance.

[0134] In Examples 1-5, polymer fibers act as a skeleton to provide adhesion sites for the iron sludge slurry. The high-temperature carbonization process, under oxygen-free conditions, releases CO to release Fe from the iron sludge. 3+ The self-reduction to zero-valent iron and the residue of polymer fibers form a carbon skeleton, making the resulting iron-based supported catalyst packing loose and porous, with high microbial loading and good organic matter adsorption effect.

[0135] In Example 5, the pH value was approximately 8.0, exceeding the aforementioned pH range of 3.5-4. Compared to Example 5, the pH values ​​of Examples 1-4 were approximately 3.7, falling within the preferred range of 3.5-4. Therefore, the iron-based supported catalyst packing materials of Examples 1-4 exhibited better microbial removal performance. It is evident that the iron-based supported catalyst packing materials obtained through any of the above treatment methods possess good microbial removal performance and can be applied to wastewater biological treatment processes and recycled as heterogeneous Fenton catalysts in Fenton processes, achieving full-process recycling of Fenton iron sludge.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for treating Fenton iron sludge, characterized in that, include: Iron mud slurry was separated from the effluent of the Fenton process; Polymer fibers are added to the iron mud slurry, so that the iron mud slurry adheres to and ages on the polymer fibers to obtain aged iron mud fibers. The ratio of the volume of the iron mud slurry to the mass of the polymer fibers is 10-100 ml: 1 g, and the aspect ratio of the polymer fibers conforms to the fiber morphology. The aged iron sludge fiber was subjected to high-temperature self-reduction carbonization at 1100℃-1200℃ for 10min-30min, and then cooled and sieved to obtain iron-based carrier catalyst filler. The iron sludge slurry separated from the Fenton process effluent includes: A weak alkaline material is added to the Fenton process effluent until the pH value of the Fenton process effluent is adjusted to 3.5-4, so that the iron ions in the Fenton process effluent are converted into iron sludge precipitate. A coagulant is added to the Fenton process effluent to allow for sedimentation and separation of the iron sludge precipitate. The amount of coagulant added is 100-500 mg / 10 L of Fenton process effluent. A strong oxidant is added to the iron mud precipitate and stirred evenly to obtain the iron mud slurry. The amount of the strong oxidant added is 100-500 mg / L of iron mud precipitate. The weakly alkaline material includes at least one of magnesium oxide, magnesium hydroxide, or magnesium carbonate, and the iron mud precipitate includes Schiele ore. The coagulant aid includes organic flocculants and inorganic flocculants. The organic flocculant includes at least one of carrageenan, xanthan gum, or sodium carboxymethyl cellulose, and the inorganic flocculant includes diatomaceous earth. The strong oxidizing agent includes at least one of potassium ferrate, potassium permanganate, or potassium perchlorate.

2. The method according to claim 1, characterized in that, During the attachment aging stage, the method further includes: Polyester polyol and cationic starch are added to the iron mud slurry, wherein the volume ratio of the polyester polyol to the iron mud slurry is 1:20-50, and the mass ratio of the cationic starch to the iron mud slurry is 1:50-100.

3. The method according to claim 2, characterized in that, The polymer fiber includes at least one of polyaramid fiber, polyimide fiber, polyurethane fiber, or viscose fiber.

4. The method according to claim 1, characterized in that, Before the step of subjecting the aged iron sludge fiber to high-temperature self-reducing carbonization at 1100℃-1200℃ for 10min-30min, the method further includes: The aged iron sludge fiber was subjected to vacuum freeze-drying for 12-24 hours.

5. A wastewater treatment method, characterized in that, include: An iron-based supported catalyst packing is added to the wastewater to be treated for a biological wastewater treatment process, wherein the iron-based supported catalyst packing is obtained by the method described in any one of claims 1-4.

6. A Fenton treatment method, characterized in that, Iron-based supported catalyst packing is used as a catalyst in the Fenton process to achieve recycling, wherein the iron-based supported catalyst packing is obtained by the method described in any one of claims 1-4.

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