Iron intercalation biochar loaded copper sulfide composite material as well as preparation method and application thereof

Abstract

The invention provides an iron intercalation biochar loaded copper sulfide composite material and a preparation method and application thereof, and the iron intercalation biochar loaded copper sulfide composite material comprises iron intercalation biochar as a substrate and copper sulfide loaded on the surface of the substrate; the iron intercalation biochar comprises biomass charcoal and iron doped on the surface and / or inside the biomass charcoal, and the iron serves as an intermediate intercalation of the biomass charcoal and copper sulfide and serves as an electron transport bridge.

Description

Technical Field

[0001] The present disclosure relates to the technical field of wastewater deep treatment, and in particular to an iron-intercalated biochar-loaded copper sulfide composite material, a preparation method and application thereof, and more specifically to an iron-intercalated biochar-loaded copper sulfide composite material, a preparation method thereof, a continuous flow reaction column and a method for degrading pollutants. Background Art

[0002] With the acceleration of industrialization and the widespread use of chemicals and pharmaceuticals, the residual presence of new pollutants such as antibiotics, endocrine disruptors, persistent organic pollutants, and microplastics in aquatic environments has become increasingly serious. These pollutants, characterized by high biotoxicity, high environmental persistence, and significant bioaccumulation, continuously enter water bodies through medical wastewater, pharmaceutical wastewater, and agricultural runoff, posing a potential threat to ecosystem balance and human health. Traditional water treatment technologies, such as biodegradation and adsorption, are unable to meet current water purification needs due to their low treatment efficiency and inability to completely degrade pollutants.

[0003] Persulfate-based advanced oxidation technologies have become a research hotspot due to their low cost, high storage and transportation stability, diverse reactive oxygen species, and targeted generation. This technology activates persulfate using heat, light, ultrasound, alkali, or homogeneous or heterogeneous activators to achieve deep mineralization of pollutants. Heterogeneous catalytic activation processes hold particular promise due to their ease of operation, mild reaction conditions, and low energy consumption. The development of efficient and stable persulfate activators is crucial for this technology.

[0004] Biochar-based composites, commonly used persulfate activators, offer advantages such as simple synthesis, abundant active functional groups, and a wide range of raw material sources. However, these materials suffer from inherent drawbacks such as low electron transfer efficiency, insufficient active site stability, and limited sustained catalytic activity, which restrict their further application in the treatment of new pollutants in water. Therefore, there is an urgent need to develop persulfate-activating materials and related technologies that can overcome these drawbacks to improve the efficiency and stability of new pollutant removal in water. Summary of the Invention

[0005] In view of this, the main purpose of the present disclosure is to provide an iron-intercalated biochar-loaded copper sulfide composite material and its preparation method and application, in order to at least partially solve at least one of the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solutions disclosed herein are as follows:

[0007] In one aspect of the present disclosure, an iron-intercalated biochar-loaded copper sulfide composite material is provided, comprising: an iron-intercalated biochar as a substrate, and copper sulfide loaded on the surface of the substrate; the iron-intercalated biochar comprises biochar and iron doped on the surface and / or inside the biochar, and the iron serves as an intermediate intercalation layer between the biochar and the copper sulfide, acting as an electron transfer bridge.

[0008] In a second aspect of the present disclosure, a method for preparing the above-mentioned iron-intercalated biochar-loaded copper sulfide composite material is provided, comprising:

[0009] mixing the biomass material and the iron source in water and drying to obtain a mixture;

[0010] calcining the mixture under an inert gas atmosphere to obtain an iron-doped biochar precursor;

[0011] A copper source and a sulfur source with a molar ratio of 1:1 were mixed and ground with an iron-doped biochar precursor, and copper sulfide was in situ grown on the surface of the iron-doped biochar to obtain an iron-intercalated biochar-loaded copper sulfide composite material.

[0012] In the third aspect of the present disclosure, a continuous flow reaction column is provided, comprising: a shell and a filter assembly filled in the shell, wherein a feed port and a discharge port are relatively provided at the upper and lower ends of the shell; the filter assembly comprises absorbent cotton and the above-mentioned iron-intercalated biochar-loaded copper sulfide composite material, wherein the iron-intercalated biochar-loaded copper sulfide composite material is filled between the absorbent cotton.

[0013] In yet another aspect of the present disclosure, there is provided a method for degrading pollutants, comprising:

[0014] Wastewater containing pollutants and a persulfate solution are introduced into the continuous flow reaction column to degrade the pollutants.

[0015] According to an embodiment of the present disclosure, a copper sulfide-loaded iron-intercalated biochar composite material is provided. This composite material comprises an iron-intercalated biochar substrate with copper sulfide loaded on the substrate surface. This composite material utilizes the electron bridging effect of the iron intercalation and the synergistic effect of the iron and copper bimetallic active centers to accelerate the decomposition of persulfate and the generation of reactive oxygen species, achieving efficient degradation of new pollutants in water. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of the preparation method of the iron-intercalated biochar-loaded copper sulfide composite material disclosed herein;

[0017] Figure 2 This is a scanning electron microscope image of the materials prepared in Example 1 and Comparative Examples 1 to 3 of the present disclosure;

[0018] Figure 3 X-ray diffraction patterns of the materials prepared in Example 1 and Comparative Examples 1 to 3 of the present disclosure;

[0019] Figure 4 This is a diagram showing the degradation effect of sulfamethazine on the materials prepared in Example 1 and Comparative Examples 1 to 4 of the present disclosure by activating persulfate;

[0020] Figure 5 This is a diagram showing the degradation effect of sulfamethazine on the materials prepared in Examples 1 to 5 activated by persulfate;

[0021] Figure 6 This is a diagram showing the degradation effect of sulfamethazine on the materials prepared in Examples 1 and 6 to 9 activated by persulfate;

[0022] Figure 7 This is a graph showing the degradation effects of the iron-intercalated biochar-loaded copper sulfide composite material prepared in Example 1 of the present disclosure on different pollutants;

[0023] Figure 8 Schematic diagram of an apparatus for treating pollutants using a continuous flow reaction column to activate a persulfate system in Example 10 of the present disclosure;

[0024] Figure 9 This is a test diagram of the degradation effect of treating pollutants using a continuous flow reaction column device in Example 10 of the present disclosure. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments.

[0026] The endpoints of the ranges and any values ​​disclosed in this disclosure are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in this disclosure.

[0027] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0028] During the implementation of the concepts outlined in this disclosure, it was discovered that conventional biochar-based composites still face numerous challenges in efficiently degrading new pollutants in water when activating persulfate: These include low reaction efficiency due to blocked electron transfer and difficulty maintaining sustained catalytic activity due to insufficient active site stability. Furthermore, conventional biochar-based composites exhibit low degradation efficiency for emerging pollutants such as sulfonamide antibiotics and persistent organic pollutants, failing to meet increasingly stringent industrial treatment requirements.

[0029] Based on this, the present disclosure provides an iron-intercalated biochar-loaded copper sulfide composite material, its preparation method, and application. An iron-intercalated biochar precursor is prepared by mixing an iron source with a biomass material and then calcining it. This achieves uniform iron doping in the biochar matrix while retaining the highly active iron (Fe² + / Fe³ + ), the iron intercalation layer plays the role of an electron bridge between the biochar and the copper sulfide, significantly accelerating the transfer efficiency of electrons, thereby solving the problem of blocked electron transfer. Further, the iron intercalation biochar precursor is ground with a copper source and a sulfur source to achieve in-situ growth of copper sulfide on the surface of the biochar, effectively combining the copper sulfide with the biochar substrate, and enhancing the overall structural stability of the composite material. At the same time, the iron and copper ions together constitute a dual active center in the composite material, which can efficiently provide electrons, significantly improve the activity of the composite material in participating in chemical reactions, and further optimize its catalytic performance. In response to the problem that the active sites of traditional biochar-based composite materials are easily deactivated during long-term operation, resulting in a decrease in catalytic performance, the present disclosure introduces sulfur species as an electron acceptor, and realizes the reversible circulation of copper ions and iron ions between different valence states through sulfur species, ensuring the continuous and effective regeneration of low-valence copper ions and iron ions, thereby giving the composite material the ability to continuously decompose persulfate, significantly improving the degradation efficiency of persulfate activation.

[0030] The degradation system constructed using the disclosed iron-intercalated biochar-loaded copper sulfide composite material exhibits excellent and stable catalytic performance, adapting to the degradation needs of a wide range of pollutants. It is highly universal and applicable to a wide range of wastewater treatment scenarios. Its mild reaction conditions and simple process flow facilitate large-scale industrial application. Furthermore, the system exhibits long-term operational stability, enabling the continuous and efficient degradation of new pollutants in wastewater, providing an efficient, stable, and economical solution for advanced wastewater treatment.

[0031] According to an embodiment of one aspect of the present disclosure, an iron-intercalated biochar-loaded copper sulfide composite material is proposed, comprising: an iron-intercalated biochar as a substrate, and copper sulfide loaded on the surface of the substrate; the iron-intercalated biochar comprises biochar and iron doped on the surface and / or inside the biochar, with the iron serving as an intermediate intercalation layer between the biochar and the copper sulfide, acting as an electron transfer bridge.

[0032] According to the embodiments of the present disclosure, there is an efficient synergistic coupling effect between iron and copper sulfide. First, the iron ions and copper ions together constitute a dual active center in the composite material, which can efficiently provide electrons, thereby significantly improving the activity of the composite material in participating in chemical reactions. Secondly, the iron intercalation can build an electron transfer bridge between biochar and copper sulfide. It can effectively reduce the resistance of electrons when transferring between biochar and copper sulfide, significantly enhance the efficiency of electron transfer, and enable persulfate to decompose more efficiently under the catalytic action of the composite material, thereby releasing free radicals with strong oxidizing ability for the degradation of various organic pollutants. In addition, sulfur species act as electron acceptors in the composite material, enabling the composite material to achieve the reaction of monovalent copper ions and divalent copper ions (Cu + / Cu² + ) and ferrous and ferric ions (Fe² + / Fe³ + ) between the reversible cycle. This reversible cycle mechanism not only ensures that Cu + and Fe² + The two key low-valent ions can be regenerated continuously and effectively, and endow the composite material with the ability to continuously decompose persulfate. + and Fe² + It is continuously oxidized to a high-valence state, and can be reduced to a low-valence state through the redistribution and transfer of electrons, thus ensuring that the composite material always has efficient catalytic activity throughout the reaction process.

[0033] According to an embodiment of the present disclosure, the mass ratio of the iron-intercalated biochar to copper sulfide is (1-7):(3-1). For example, the mass ratio can be 1:1, 3:1, 5:1, 7:1, 1:3, etc. The molar amount of the copper source and the molar amount of the sulfur source required to load 1 g of copper sulfide are 0.01 mol each.

[0034] When the amount of copper sulfide added is too low, the number of active sites on the surface of the composite material will be reduced, the activity of the composite material in catalytic degradation reactions will be weakened, and the reaction rate and efficiency will be reduced; when the amount of copper sulfide added is excessive, an excessively thick coating layer will be formed on the surface of the iron-intercalated biochar particles, hindering the effective contact between the iron active center and the reaction substrate, and also causing the catalytic activity of the composite material to decrease.

[0035] According to an embodiment of the second aspect of the present disclosure, a method for preparing the above-mentioned iron-intercalated biochar-loaded copper sulfide composite material is proposed. Figure 1 This is a flow chart of the preparation method of the iron-intercalated biochar-loaded copper sulfide composite material disclosed in the present invention, as shown in FIG. Figure 1 As shown, the preparation method includes steps S1 to S3.

[0036] Step S1: mixing the biomass material and the iron source in water and drying to obtain a mixture;

[0037] Step S2: calcining the mixture under an inert gas atmosphere to obtain an iron-doped biochar precursor;

[0038] Step S3: mixing and grinding a copper source and a sulfur source with a molar ratio of 1:1 with an iron-doped biochar precursor, and in situ growing copper sulfide on the surface of the iron-doped biochar to obtain an iron-intercalated biochar-loaded copper sulfide composite material.

[0039] According to the embodiment of the present disclosure, the biomass material and the iron source are mixed in water, and the porous structure and functional groups of the biomass are used to adsorb iron ions to ensure uniform distribution of the iron source; then, the biomass is calcined under an inert gas atmosphere to pyrolyze the biomass into biochar, while the iron source forms Fe² + / Fe³ + The mixed valence active centers are embedded in the biochar structure to retain high reactivity; finally, equimolar copper source is ground with sulfur source and iron-doped biochar precursor, and copper sulfide nanoparticles are generated with the help of hydrated crystal microreaction environment. Mechanical force is used to promote interfacial chemical bonding to achieve in-situ uniform loading and strong bonding of copper sulfide.

[0040] The disclosed preparation method, which uses water as a medium and agricultural waste as a raw material, requires no organic solvents. The process is simple and cost-effective, making it suitable for large-scale production and for treating a variety of difficult-to-degrade organic pollutants. The equimolar ratio of the copper and sulfur sources ensures that the copper and sulfur ions fully combine to form copper sulfide, while also avoiding the waste of raw materials, the formation of byproducts, and the degradation of material properties caused by an excess of either component.

[0041] According to the embodiments of the present disclosure, the biomass material includes: any one of corn cobs, rice husks, and straw. The above-mentioned biomass materials are inexpensive, readily available in large quantities, and can effectively reduce costs. The biochar formed after treatment has a natural porous structure, which can increase the specific surface area of ​​the material and improve the loading efficiency. At the same time, it provides a stable physical support framework for the composite material to optimize the mass transfer performance.

[0042] According to embodiments of the present disclosure, the amount of biomass material used is 20-30 g / L, for example, 20 g / L, 23 g / L, 25 g / L, 27 g / L, 30 g / L, etc.; the molar concentration of the iron source is 6-8 mM, for example, 6 mM, 6.5 mM, 7 mM, 7.5 mM, 8 mM, etc. When the amounts of biomass material and iron source are within these ranges, the biomass material is fully impregnated with the iron source solvent, providing an ideal chemical environment and material basis for the synthesis of the iron-intercalated biochar precursor.

[0043] According to the embodiments of the present disclosure, in actual operation, the biomass material can be ground and sieved first. For example, the biomass material can be sieved using a 10-mesh sieve to remove larger particles of impurities in the biomass material. The biomass material is then rinsed three times with pure water and three times with anhydrous ethanol, and dried at 60°C for later use.

[0044] The iron source includes one or more of ferrous chloride tetrahydrate, ferrous nitrate hexahydrate, and ferrous sulfate heptahydrate. The use of the above-mentioned soluble ferrous salts as the iron source not only has the significant advantages of low price and easy availability of raw materials, but also the ferrous salts can undergo thermal decomposition and redox reactions during the calcination reaction, so that the iron element is uniformly doped in the activated carbon structure in the form of divalent iron and trivalent iron, forming a metallic iron active center with a specific valence distribution, thereby effectively improving the functional performance of the iron-intercalated biochar-based material in the target application.

[0045] The copper source includes one or more of copper sulfate pentahydrate, copper chloride dihydrate, and copper nitrate trihydrate, and the sulfur source includes one or more of sodium sulfide nonahydrate and thiourea. The hydrated copper source, due to the presence of crystalline water, forms a moist microenvironment during the grinding process. The reducing sulfur-containing sulfur source releases active sulfur components such as sulfide ions or thiosulfate, which react with copper ions in the copper source to form copper sulfide. This allows for in-situ synthesis of copper sulfide without the need for additional solvents, simplifying the preparation process.

[0046] In step S1, the biomass material and the iron source are mixed in water for more than 12 hours to ensure that the iron source and the biomass material are fully mixed and the iron intercalation layer is uniformly constructed.

[0047] The calcination temperature in step S2 is 500-900°C, for example, 500°C, 600°C, 700°C, 800°C, 900°C, etc.; the calcination time is 2-4 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, etc. Calcination temperatures and times within the above ranges facilitate the thorough calcination of the biomass material. Through processes such as dehydration, decarbonization, and chemical bond breakage, a biochar structure rich in functional groups such as hydroxyl, carboxyl, and carbonyl groups is generated. These active groups provide abundant binding sites for the chemical adsorption and intercalation of iron ions. Furthermore, controlled calcination conditions ensure a thorough solid-phase reaction between the iron source and the biomass material at high temperatures, allowing the iron element to be uniformly incorporated into the biochar lattice in the form of ferrous and ferric ferric states, forming iron active centers with high catalytic activity. This facilitates the thorough calcination of the biomass material, ensuring the formation of biochar functional groups, while also effectively binding to the iron source to form an iron-doped biochar precursor with excellent catalytic performance.

[0048] The grinding time in step S3 is 5 to 10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc. The grinding process allows the copper source and the sulfur source to be fully mixed and reacted under the action of mechanical force, thereby promoting the uniform loading of copper sulfide on the iron-intercalated biochar. The grinding reaction process is short, the process is simple, and the operation is convenient, providing a low-cost, easily scalable method for the efficient preparation of iron-intercalated biochar-based copper sulfide composite materials.

[0049] In step S3, after grinding and mixing, washing and drying are also performed. The washing step involves washing the ground material three times with deionized water and three times with anhydrous ethanol. After each wash, the sample is centrifuged to precipitate, and the upper washing solution is discarded to remove impurities. The drying step can be performed at a temperature of 60-80°C for 6-8 hours. Appropriate drying temperature and duration facilitate the removal of solvent and moisture from the composite material, resulting in a black solid iron-intercalated biochar-loaded copper sulfide composite material (CuS@Fe-CCBC).

[0050] According to an embodiment of the third aspect of the present disclosure, a continuous flow reaction column is proposed, comprising: a shell and a filter assembly filled in the shell, wherein a feed port and a discharge port are relatively arranged at the upper and lower ends of the shell; the filter assembly comprises absorbent cotton and the above-mentioned iron-intercalated biochar-loaded copper sulfide composite material, wherein the iron-intercalated biochar-loaded copper sulfide composite material is filled between the absorbent cotton.

[0051] According to the embodiments of the present disclosure, the feed port and the discharge port at the upper and lower ends of the continuous flow reaction column shell form a directional flow channel to ensure the continuous passage of wastewater and persulfate solution; the filter assembly is filled with absorbent cotton and iron-intercalated biochar-loaded copper sulfide composite material. During actual operation, for example, a solution of iron-intercalated biochar-loaded copper sulfide composite material can be added and dispersed in the middle of the absorbent cotton layer. The physical support and screening effect of the absorbent cotton are used to fix the composite material and evenly disperse the fluid, while increasing the contact area between the material and the composite material. The porous structure and high activity sites of the composite material can adsorb and enrich pollutants, and the iron and copper bimetallic centers synergistically activate persulfate to produce active free radicals, accelerating the degradation process. In the continuous flow mode, the material residence time and flow rate can be precisely controlled, combined with the stable catalytic performance of the composite material, to achieve continuous and efficient removal of pollutants, and the process operation is simple and energy consumption is low, which is suitable for industrial continuous treatment of wastewater, for example, it can achieve long-term removal of pollutants in the secondary effluent background of sewage treatment plants.

[0052] According to the embodiments of the present disclosure, the addition amount of the iron-intercalated biochar-loaded copper sulfide composite material to the filling volume of the absorbent cotton is 15~30 g / L, for example, it can be 15 g / L, 20 g / L, 25 g / L, 30 g / L, etc., to ensure that its active sites are in full contact with persulfate and pollutants, thereby improving the free radical yield and degradation efficiency.

[0053] According to an embodiment of yet another aspect of the present disclosure, a method for degrading pollutants is proposed, comprising: introducing wastewater containing pollutants and a persulfate solution into an upward continuous flow reaction column to degrade the pollutants.

[0054] According to the embodiments of the present disclosure, continuous dynamic contact between wastewater, persulfate solution and composite material is achieved through a continuous flow reaction column, and the synergistic catalytic effect of the iron-intercalated biochar-loaded copper sulfide composite material is utilized to enhance the mass transfer efficiency under the promotion of directional fluid, continuously activate persulfate to produce active free radicals, and degrade pollutants into small-molecule inorganic substances through reactions such as bond breaking and ring opening.

[0055] According to an embodiment of the present disclosure, the concentration of the persulfate solution is 0.2-0.6 mM, and the persulfate includes at least one of sodium persulfate and potassium persulfate. In actual operation, a persulfate with a mass fraction greater than 42% can be selected. Pollutants include at least one of sulfamethazine, atrazine, primidone, sulfamethazine, diclofenac sodium, and carbamazepine. At room temperature, the iron-intercalated biochar-loaded copper sulfide composite material activates persulfate to produce more abundant hydroxyl radicals, sulfate radicals, superoxide radicals, and singlet oxygen, which react with the pollutants sulfamethazine, atrazine, primidone, sulfamethazine, diclofenac sodium, and carbamazepine in water to undergo hydroxylation, ketonization, decarboxylation, demethylation, side chain decarboxylation, and aromatic ring oxidation, thereby effectively degrading a variety of difficult-to-degrade organic pollutants.

[0056] According to an embodiment of the present disclosure, a method for degrading sulfamethazine is proposed, using the degradation of the pollutant as an example. The method includes: filling a cylindrical organic glass tube with a diameter of 2 cm, a height of 6.8 cm, and a volume of approximately 21 mL with cotton wool. An aqueous solution of 400 mg of an iron-intercalated biochar-loaded copper sulfide composite material is dropwise dispersed between the cotton wool layers to form a continuous flow reaction column.

[0057] The secondary effluent containing sulfamethazine and the persulfate solution were simultaneously introduced into a continuous flow reaction column through two separate pipelines. The concentration of the secondary effluent containing sulfamethazine was 10 mg / L, and the concentration of the persulfate solution was 0.6 mM. The flow rate in both pipelines was controlled at 0.25 mL / min, and the hydraulic retention time in the reaction column was approximately 42 minutes, allowing for the degradation of the sulfamethazine in the final effluent.

[0058] According to the embodiments of the present disclosure, the wastewater containing pollutants during the degradation process can be an acidic, neutral or alkaline system. The iron-intercalated biochar-loaded copper sulfide composite material disclosed in the present disclosure exhibits good catalytic effect in the pH range of 3 to 11, and has the advantage of a wide pH applicability range.

[0059] In practical applications, persulfate and iron-intercalated biochar-based composite materials can be directly added to wastewater containing pollutants to degrade the pollutants. The amount of persulfate added to the wastewater can be 0.1-0.2 g / L, and the amount of iron-intercalated biochar-based composite material added to the wastewater can be 0.2-0.5 mM.

[0060] In order to make the purpose, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific examples and drawings. Where specific techniques or conditions are not specified in the examples, they are all conventional methods and can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. It should be noted that the methods provided in the present disclosure are all conventional methods unless otherwise specified, and the reactants and reagents can be obtained from public commercial channels unless otherwise specified.

[0061] Example 1:

[0062] This embodiment provides an iron-intercalated biochar-loaded copper sulfide composite material, the specific preparation method of which is as follows:

[0063] Corncob waste was sieved through a 10-mesh sieve, rinsed three times with deionized water and three times with ethanol, and dried at 60°C to obtain corncob powder. 1.5 g of corncob powder was dispersed in 50 mL of 8 mM ferrous chloride tetrahydrate (FeCl2·4H2O) solution, rapidly stirred at room temperature for 12 h, and dried at 80°C to obtain a mixture.

[0064] The obtained mixture was placed in a crucible and placed in a tube furnace. Under a nitrogen (N2) atmosphere, the temperature was increased at a rate of 5°C / min to 800°C, and the mixture was kept at this temperature for 2 h. After cooling, an iron-doped biochar precursor was obtained.

[0065] 0.1 g of iron-doped biochar precursor, 0.755 g of copper nitrate trihydrate (Cu(NO₃)₃·3H₂O), and 0.750 g of sodium sulfide nonahydrate (Na₂S·9H₂O) were ground in a mortar for 5 minutes to obtain the reacted material. The reacted material was washed three times with deionized water and three times with anhydrous ethanol. The resulting precipitate was centrifuged and dried at 60°C for 8 hours. After grinding, the iron-intercalated biochar-supported copper sulfide composite material 1 (CuS@Fe-CCBC-1) was obtained. The mass ratio of the iron-intercalated biochar to copper sulfide was 3:1.

[0066] Example 2:

[0067] This embodiment provides an iron-intercalated biochar-loaded copper sulfide composite material. The specific preparation method is different from the preparation method in Example 1 in that the calcination temperature is 500°C. The other steps are the same as in Example 1, and an iron-intercalated biochar-loaded copper sulfide composite material 2 (CuS@Fe-CCBC-2) is prepared.

[0068] Example 3:

[0069] This embodiment provides an iron-intercalated biochar-loaded copper sulfide composite material. The specific preparation method is different from the preparation method in Example 1 in that the calcination temperature is 600°C. The other steps are the same as in Example 1, and an iron-intercalated biochar-loaded copper sulfide composite material 3 (CuS@Fe-CCBC-3) is prepared.

[0070] Example 4:

[0071] This embodiment provides an iron-intercalated biochar-loaded copper sulfide composite material. The specific preparation method is different from the preparation method in Example 1 in that the calcination temperature is 700°C. The other steps are the same as in Example 1, and an iron-intercalated biochar-loaded copper sulfide composite material 4 (CuS@Fe-CCBC-4) is prepared.

[0072] Example 5:

[0073] This embodiment provides an iron-intercalated biochar-loaded copper sulfide composite material. The specific preparation method is different from the preparation method in Example 1 in that the calcination temperature is 900°C. The other steps are the same as in Example 1, and an iron-intercalated biochar-loaded copper sulfide composite material 5 (CuS@Fe-CCBC-5) is prepared.

[0074] Example 6:

[0075] This embodiment provides an iron-intercalated biochar-loaded copper sulfide composite material. The preparation method differs from that of Example 1 in that the amounts of copper nitrate trihydrate and sodium sulfide nonahydrate added are different. The other steps are the same as those of Example 1. An iron-intercalated biochar-loaded copper sulfide composite material 6 (CuS@Fe-CCBC-6) is prepared, wherein the mass ratio of iron-intercalated biochar to copper sulfide is 1:1.

[0076] Example 7:

[0077] This embodiment provides an iron-intercalated biochar-loaded copper sulfide composite material. The preparation method differs from that of Example 1 in that the amounts of copper nitrate trihydrate and sodium sulfide nonahydrate added are different. The other steps are the same as those of Example 1. An iron-intercalated biochar-loaded copper sulfide composite material 7 (CuS@Fe-CCBC-7) is prepared, wherein the mass ratio of iron-intercalated biochar to copper sulfide is 5:1.

[0078] Example 8:

[0079] This embodiment provides an iron-intercalated biochar-loaded copper sulfide composite material. The preparation method differs from that of Example 1 in that the amounts of copper nitrate trihydrate and sodium sulfide nonahydrate added are different. The other steps are the same as those of Example 1. An iron-intercalated biochar-loaded copper sulfide composite material 8 (CuS@Fe-CCBC-8) is prepared, wherein the mass ratio of iron-intercalated biochar to copper sulfide is 7:1.

[0080] Example 9:

[0081] This embodiment provides an iron-intercalated biochar-loaded copper sulfide composite material. The preparation method differs from that of Example 1 in that the amounts of copper nitrate trihydrate and sodium sulfide nonahydrate added are different. The other steps are the same as those of Example 1. An iron-intercalated biochar-loaded copper sulfide composite material 9 (CuS@Fe-CCBC-9) is prepared, wherein the mass ratio of iron-intercalated biochar to copper sulfide is 1:3.

[0082] Comparative Example 1

[0083] This comparative example provides a method for preparing a corncob-derived biochar material, comprising:

[0084] The corncob waste residue was screened through a 10-mesh sieve, rinsed with deionized water and ethanol three times each, and dried at 60° C. to obtain corncob powder.

[0085] 1.5 g corn cob powder was placed in a crucible and placed in a tube furnace. Under a nitrogen (N2) atmosphere, the temperature was increased at a rate of 5 °C / min to 800 °C, and the temperature was kept for 2 h. After cooling, corn cob-derived biochar material (CCBC) was obtained.

[0086] Comparative Example 2

[0087] This comparative example provides a method for preparing an iron-doped biochar material, comprising:

[0088] Corncob waste was sieved through a 10-mesh sieve, rinsed three times with deionized water and three times with ethanol, and dried at 60°C to obtain corncob powder. 1.5 g of corncob powder was dispersed in 50 mL of 8 mM ferrous chloride tetrahydrate (FeCl2·4H2O) solution, rapidly stirred at room temperature for 12 h, and dried at 80°C to obtain a mixture.

[0089] The obtained mixture was placed in a crucible and placed in a tube furnace. Under a nitrogen (N2) atmosphere, the temperature was increased at a rate of 5°C / min to 800°C, and the reaction was kept at this temperature for 2 h. After cooling, iron-doped biochar material (Fe-CCBC) was obtained.

[0090] Comparative Example 3

[0091] This comparative example provides a method for preparing a copper sulfide material, comprising:

[0092] First, Cu(NO3)3·3H2O and Na2S·9H2O in equal molar ratios were placed in a mortar and fully ground for 5 min to obtain the reacted sample.

[0093] (2) The sample obtained after the reaction in (1) was washed with deionized water and anhydrous ethanol three times each, and the precipitate was centrifuged each time and then dried at 60°C for 8 h. After grinding, a black solid was obtained, which was copper sulfide (CuS).

[0094] Comparative Example 4

[0095] This comparative example provides a method for preparing a corncob-derived biochar-loaded copper sulfide material, comprising:

[0096] Corncob waste was sieved through a 10-mesh sieve, rinsed three times with deionized water and three times with ethanol, and then dried at 60°C to obtain corncob powder. 1.5 g of corncob powder was placed in a crucible and placed in a tube furnace. Under a nitrogen (N2) atmosphere, the temperature was increased at a rate of 5°C / min to 800°C. The temperature was maintained for 2 hours, and the corncob-derived biochar was obtained after cooling.

[0097] 0.1 g of corncob-derived biochar, 0.251 g of copper nitrate trihydrate (Cu(NO₃)₃·3H₂O), and 0.249 g of sodium sulfide nonahydrate (Na₂S·9H₂O) were ground in a mortar for 5 minutes to obtain the reacted material. The reacted material was washed three times with deionized water and three times with anhydrous ethanol. The resulting precipitate was centrifuged and dried at 60°C for 8 hours. After grinding, corncob-derived biochar-supported copper sulfide (CuS@CCBC) was obtained.

[0098] The material structures prepared in Example 1 and Comparative Examples 1 to 3 were characterized.

[0099] Figure 2 This is a scanning electron microscope image of the materials prepared in Example 1 and Comparative Examples 1 to 3 of the present disclosure. Figure 2 a in the figure is a scanning electron microscope image of the material prepared in Comparative Example 1; Figure 2 b is a scanning electron microscope image of the material prepared in Comparative Example 2; Figure 2c is a scanning electron microscope image of the material prepared in Comparative Example 3; Figure 2 d in the figure is a scanning electron microscope image of the material prepared in Example 1.

[0100] like Figure 2 As shown in a to d in the figure, the iron-intercalated biochar-loaded copper sulfide composite material prepared in Example 1, compared with the materials in Comparative Examples 1 to 3, contains copper sulfide, metallic iron nanoparticles and honeycomb corncob-derived biochar (CCBC), presenting a composite structure.

[0101] Figure 3 1 is the X-ray diffraction pattern of the materials prepared in Example 1 and Comparative Examples 1 to 3 of the present disclosure.

[0102] like Figure 3 As shown, the characteristic diffraction peaks of the iron-intercalated biochar-loaded copper sulfide composite prepared in Example 1 correspond to standard metallic iron (PDF 06-0696) and copper sulfide (CuS) (PDF 06-0464), respectively. The diffraction peaks are clear and intense, with no impurity peaks observed, indicating high crystallinity and purity. The metallic characteristic peaks of Fe-CCBC and CuS are consistent with those of standard charts for metallic iron, iron carbide (Fe3C), and CuS, demonstrating the successful bonding of Fe to the biochar and the successful synthesis of CuS. The characteristic peaks of Fe-CCBC are consistent with those of CCBC, indicating that Fe-CCBC can retain the amorphous structure of the original biochar.

[0103] The materials prepared in Examples 1 to 9 and Comparative Examples 1 to 4 were used as activation materials to degrade sulfamethazine. The specific degradation method is as follows:

[0104] 0.1 g / L of the materials prepared in Examples 1-9 and Comparative Examples 1-4 were added to water containing 5 mg / L sulfamethazine, and the mixture was mixed. After 30 minutes, adsorption equilibrium was reached. A persulfate solution was then added to the water, with a concentration ranging from 0.2 to 0.6 mM, specifically comprising at least one of sodium persulfate and potassium persulfate, with a mass fraction greater than 42%. The reaction was carried out at room temperature with mechanical stirring for 40 minutes. After completion, the water quality was tested.

[0105] Figure 4 The degradation efficiency of sulfamethazine by persulfate activated with the materials prepared in Example 1 and Comparative Examples 1 to 4 is shown in Table 1.

[0106] Table 1

[0107]

[0108] like Figure 4 As shown in Table 1, the CuS@Fe-CCBC-1 composite material prepared in Example 1 can completely degrade sulfamethazine. Compared with the materials prepared in other comparative examples, it can more efficiently decompose persulfate and achieve a more significant pollutant degradation effect.

[0109] In addition, in order to characterize the synergistic effect of active materials and persulfate in the pollutant degradation system, comparative tests were carried out with only persulfate added (without adding activation materials) and only active materials added (without adding persulfate).

[0110] The degradation system involved adding only persulfate: A specific concentration of persulfate was added to an aqueous solution containing sulfamethazine. The reaction was allowed to proceed at room temperature with magnetic stirring for 40 minutes. The water quality was then tested after the treatment. The results showed that sulfamethazine had been degraded by 11.64%.

[0111] Only active materials were added to the degradation system: 0.1 g of each of the materials from Comparative Examples 1–4 and the CuS@Fe-CCBC-1 from Example 1 was added to an aqueous solution containing sulfamethazine. The reaction was carried out at room temperature with mechanical stirring for 40 minutes. The water quality was then tested after the reaction. The results showed that sulfamethazine was not effectively degraded, with the maximum pollutant degradation efficiency exceeding 11.07%.

[0112] like Figure 4 The results indicate that persulfate, without active material catalysis, can only produce a small amount of free radicals through self-decomposition, resulting in limited degradation capabilities. The materials in Comparative Examples 1-4 and the CuS@Fe-CCBC in Example 1 showed no significant adsorption or spontaneous catalytic activity towards sulfamethazine. Therefore, the degradation process requires the synergistic effect of the active material and persulfate.

[0113] Figure 5 This is a diagram showing the degradation effect of sulfamethazine on the materials prepared in Examples 1 to 5 activated by persulfate.

[0114] like Figure 5 As shown, the CuS@Fe-CCBC-1 composite material prepared by calcining at 800°C in this disclosure exhibits superior persulfate decomposition and achieves more significant degradation. Composite materials prepared at other calcination temperatures also achieved over 70% degradation of sulfamethazine within 40 minutes.

[0115] Figure 6 This is a diagram showing the degradation effect of sulfamethazine on the materials prepared in Examples 1 and 6 to 9 of the present disclosure by activating persulfate.

[0116] like Figure 6 As shown in the results, the composite material with a mass ratio of 3:1 between iron-intercalated biochar and copper sulfide exhibited better persulfate decomposition and achieved more significant degradation. Composite materials synthesized with other ratios also achieved over 70% degradation of sulfamethazine in 40 minutes.

[0117] The iron-intercalated biochar-loaded copper sulfide composite material prepared in Example 1 was used to activate persulfate to degrade atrazine, primidone, sulfamethazine, diclofenac sodium and carbamazepine. Figure 7 This is a diagram showing the degradation effect of the iron-intercalated biochar-loaded copper sulfide composite material prepared in Example 1 of the present disclosure on different pollutants.

[0118] like Figure 7 As shown, the iron-intercalated biochar-supported copper sulfide composite prepared in Example 1 exhibited good degradation effects on atrazine, primidone, sulfamethoxazole, diclofenac sodium, and carbamazepine using activated persulfate. This demonstrates the composite material's broad applicability and efficient catalytic performance, enabling it to effectively treat a wide range of organic pollutants and demonstrating its significant potential and application value in wastewater treatment.

[0119] Example 10

[0120] This embodiment provides a continuous flow reaction column, and uses the continuous flow reaction column to activate a persulfate system for wastewater treatment.

[0121] The construction and operation method and process of the continuous flow reaction column are as follows:

[0122] A cylindrical organic glass tube with a diameter of 2 cm, a height of 6.8 cm, and a volume of approximately 21 mL was filled with absorbent cotton, and 400 mg of the aqueous solution of CuS@Fe-CCBC-1 in Example 1 was dropwise dispersed between the absorbent cotton layers to prepare a continuous flow reaction column.

[0123] The following secondary effluent from the secondary sedimentation tank of a Beijing municipal wastewater treatment plant, containing sulfamethazine before advanced treatment, is considered secondary effluent. The secondary effluent contains 1.25 mg / L total nitrogen, 0.35 mg / L total phosphorus, 21 mg / L chemical oxygen demand (COD), 3.40 mg / L total organic carbon (TOC), and a pH of 7.27.

[0124] Figure 8 Schematic diagram of the device for treating pollutants using a continuous flow reaction column to activate a persulfate system in Example 10 of the present disclosure.

[0125] like Figure 8As shown, the secondary effluent containing sulfamethazine and the persulfate solution were simultaneously introduced into a continuous flow reactor column through two separate pipelines. The concentration of the secondary effluent containing sulfamethazine (SMR) was 10 mg / L, and the concentration of the potassium persulfate (PMS) solution was 0.6 mM. The potassium persulfate injection rate was 0.3 mM, and the sulfamethazine inlet concentration was 5 mg / L. The flow rate in both pipelines was controlled at 0.25 mL / min, and the hydraulic retention time in the reactor column was approximately 42 minutes. The sulfamethazine contaminant was continuously degraded, and the water quality was tested after treatment.

[0126] Figure 9 Figures showing the pollutant degradation performance test using the continuous flow reaction column apparatus in Example 10 of the present disclosure. Figure a shows the pollutant removal rate after 7 days of continuous operation; figure b shows the pollutant mineralization rate after 7 days of continuous operation; figure c shows the potassium persulfate utilization rate after 7 days of continuous operation; and figure d shows the average ion leaching concentration after 7 days of continuous operation.

[0127] like Figure 9 As shown in Figures a–d, the continuous-flow reaction column device operated stably for at least seven days, achieving a sulfamethazine removal rate consistently exceeding 95% in the secondary effluent and an average mineralization rate of 46.10%. The PMS utilization rate remained above 90%, with average copper ion leaching concentrations consistently below 0.5 mg / L and average iron ion leaching concentrations below 0.15 mg / L. These results demonstrate the environmentally friendly nature of the persulfate-activated technology based on the iron-intercalated biochar-supported copper sulfide composite. The system's exceptional performance stems not only from its thorough degradation of pollutants but also from its efficient PMS utilization and minimal residual metal ions.

[0128] The present disclosure provides an iron-intercalated biochar-loaded copper sulfide composite material and its preparation method and application, which improves the electron transfer performance and active center of the composite material. Among them, the co-loading of iron and copper sulfide has a synergistic effect. The iron intercalation can promote the electron transfer process and increase the active sites. The sulfur species doping can act as an electron donor to promote the redox cycle. Specifically, on the one hand, metallic iron acts as an intermediate intercalation layer and acts as an iron-mediated electron bridge, which can promote the transfer of electrons from the biochar substrate to copper sulfide, and finally the electrons transferred from copper sulfide to persulfate realize its efficient activation; on the other hand, the sulfur species provides electrons for the dual active centers of iron and copper in the process of step-by-step oxidation, forming Cu + / Cu 2+ 、Fe 2+ / Fe 3+ Dual redox cycles effectively promote Cu + and Fe 2+Regeneration, giving the composite material the ability to continuously activate persulfate. The above synergistic effect accelerates the decomposition of persulfate and the production of various reactive oxygen species, achieving higher catalytic activity. Furthermore, the iron-intercalated biochar-loaded copper sulfide composite material is used as a persulfate activator to remove sulfamethazine, atrazine, primidone, sulfamethazine, diclofenac sodium or carbamazepine from water. It has the advantages of high removal rate, mild reaction conditions, simple process flow, green environmental protection, energy saving, simple and feasible preparation method of catalytic materials, easy recovery and regeneration.

[0129] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. An iron-intercalated biochar-loaded copper sulfide composite material, characterized in that: include: Iron-intercalated biochar is used as a substrate, and copper sulfide is loaded on the surface of the substrate; The iron-intercalated biochar comprises biochar and iron doped on the surface and / or inside of the biochar. The iron serves as an intermediate intercalation layer between the biochar and copper sulfide and acts as an electron transfer bridge.

2. The iron-intercalated biochar-loaded copper sulfide composite material according to claim 1, characterized in that: The mass ratio of the iron-intercalated biochar to copper sulfide is (1-7): (3:-1).

3. A method for preparing the iron-intercalated biochar-loaded copper sulfide composite material according to any one of claims 1 to 2, characterized in that: The preparation method comprises: mixing the biomass material and the iron source in water and drying to obtain a mixture; calcining the mixture under an inert gas atmosphere to obtain an iron-doped biochar precursor; A copper source and a sulfur source with a molar ratio of 1:1 are mixed and ground with the iron-doped biochar precursor, and copper sulfide is in situ grown on the surface of the iron-doped biochar to obtain an iron-intercalated biochar-loaded copper sulfide composite material.

4. The preparation method according to claim 3, characterized in that The biomass material includes any one of corn cobs, rice husks, and straw; The iron source includes one or more of ferrous chloride tetrahydrate, ferrous nitrate hexahydrate, and ferrous sulfate heptahydrate; The copper source includes one or more of copper sulfate pentahydrate, copper chloride dihydrate, and copper nitrate trihydrate; The sulfur source includes one or more of sodium sulfide nonahydrate and thiourea.

5. The preparation method according to claim 3, characterized in that The amount of the biomass material is 20-30 g / L, The molar concentration of the iron source is 6-8 mM.

6. The preparation method according to claim 3, characterized in that The calcination temperature is 500-900°C and the time is 2-4 hours. The grinding time is 5 to 10 min.

7. A continuous flow reaction column, characterized in that It includes: a shell and a filter assembly filled in the shell, The upper and lower ends of the shell are oppositely provided with a feed port and a discharge port; The filter assembly includes absorbent cotton and the iron-intercalated biochar-loaded copper sulfide composite material according to any one of claims 1 to 2, wherein the iron-intercalated biochar-loaded copper sulfide composite material is filled between the absorbent cottons.

8. The continuous flow reaction column according to claim 7, characterized in that The amount of the iron-intercalated biochar-loaded copper sulfide composite material added to the filling volume of the absorbent cotton is 15-30 g / L.

9. A method for degrading pollutants, characterized in that: The method comprises: Wastewater containing pollutants and a persulfate solution are introduced into the continuous flow reaction column as claimed in claim 7 to degrade the pollutants.

10. The method according to claim 9, characterized in that The concentration of the persulfate solution is 0.2-0.6 mM, and the persulfate includes at least one of sodium persulfate and potassium persulfate. The pollutants include at least one of sulfamethazine, atrazine, primidone, sulfamethazine, diclofenac sodium and carbamazepine.

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