Nitrogen-doped biochar supported copper sulfide composite material, preparation method and application thereof

Abstract

The present application relates to nitrogen-doped biochar supported copper sulfide composite material and its preparation method and application, and belongs to the technical field of water pollution control. The nitrogen-doped biochar supported copper sulfide composite material can be used to activate persulfate to degrade organic pollutants in water, can significantly improve the catalytic degradation performance of biochar material, optimize the non-radical pathway of generating singlet oxygen and the radical pathway of generating sulfate radicals, hydroxyl radicals and superoxide radicals by activating peroxymonosulfate, and ultimately achieve the purpose of efficient synergistic degradation of organic pollutants. The composite material can realize the resource utilization of wheat straw and the efficient removal of dyes in water, achieving the purpose of waste treatment. The catalytic material is simple to prepare, the raw materials are cheap, and industrialization is easy to realize. The organic matter removal efficiency is high, storage and addition are convenient, the pH range of wastewater is wide, and the catalytic material has great potential and wide application prospect in the field of dye wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of water pollution control technology, and in particular to nitrogen-doped biochar-supported copper sulfide composite materials, their preparation methods, and applications. Background Technology

[0002] Dyes are widely used in industries such as textiles, leather, papermaking, and inks. Nearly 10% of these dyes are wasted during manufacturing and processing and subsequently released into the environment. Azo dyes are the most common type, accounting for approximately 70% of global dye consumption. Each year, about 300,000 tons of wastewater rich in azo dyes are discharged directly into natural water bodies without treatment, making them a common water pollutant. Once in water, azo dyes impart a deep color, damage the aquatic ecosystem, and reduce the water's biodegradability. Furthermore, azo dyes can cause persistent and severe illnesses in humans, including hypertension, sporadic diseases, convulsions, and cancer. Therefore, it is essential to treat azo dyes before they enter water bodies to minimize their potential harm to the aquatic environment and humans.

[0003] Currently, the main methods for removing dyes from wastewater include physical methods, biological methods, and advanced oxidation methods. Physical methods separate or enrich dyes through physical processes for removal from the aqueous phase, primarily including adsorption and membrane separation. While effective at removing azo dyes from water, these methods do not degrade them; their molecular structure remains unchanged, posing a risk of secondary pollution. Biological methods utilize the metabolism of microorganisms to degrade pollutants, mainly including anaerobic, aerobic, and anaerobic-aerobic methods. These methods have low operating costs, treat large volumes of water, and produce no secondary pollution, but they require large land areas, have long treatment cycles, and inconsistent effectiveness. Furthermore, dye wastewater is highly toxic and has poor biodegradability, making it unsuitable for microbial growth and reproduction. Therefore, new methods are needed to achieve green and efficient dye degradation and removal.

[0004] Advanced oxidation processes (AOPs) utilize various activation methods (energy inputs such as light, electricity, sound, and waves, and catalyst activation) to interact with oxidants and generate highly oxidizing hydroxyl radicals (·OH), which degrade dyes into small molecule pollutants or even completely mineralize them. Besides AOPs based on ·OH as the main active substance, there are also AOPs that can generate SO4. - • AOPs with SR-AOPs as the main active substances, whose main oxidizing agent is persulfate (PS), mainly including permonosulfate (PMS, HSO5). - ) and persulfate (PDS, S2O8) 2- PDS is relatively cheaper and more stable than PMS, and has similar oxidizing power, making it a promising oxidant. SO4 -Compared to ·OH, SR-AOPs have higher redox potentials and longer half-lives, and their applicable pH range is relatively wider. PMS and PDS are themselves oxidants, but they are relatively stable at room temperature and pressure, and their oxidizing ability for organic pollutants is relatively low. Therefore, they need to be activated to break their OO bonds, producing highly oxidizing active substances (such as SO42-). - To enhance its ability to degrade dyes, various activation methods are used in SR-AOPs, including ultraviolet light, ultrasound, heat, and transition metals and their oxides / sulfides. Transition metals (Co, Fe, Cu, etc.) and their oxides / sulfides (Fe3O4, CuO, Co3O4, FeS, CuS, etc.) can efficiently activate PS to generate reactive oxygen species. CuS is a typical p-type semiconductor material, valued for its unique conductivity, low toxicity, and reusability. In recent years, it has received increasing attention in the field of persulfate activation. CuS has been proven to effectively activate persulfates to generate reactive oxygen species. To improve the utilization rate of CuS, a suitable carrier is usually required to maintain good dispersion of CuS particles and prevent agglomeration.

[0005] Biochar (BC) is a type of porous carbon material obtained by pyrolyzing biomass raw materials such as wheat straw and sawdust under anaerobic or anoxic conditions. Due to its wide availability of raw materials, simple preparation process, low cost, large specific surface area, and good catalytic effect, biochar is currently a hot research topic. Biochar can act as an electron donor in SR-AOPs, providing electrons to PS to generate reactive oxygen species. Furthermore, biochar can act as an electron shuttle in SR-AOPs, transferring electrons from pollutants adsorbed on its surface to PS to achieve the oxidative degradation of pollutants. However, biochar obtained from direct pyrolysis of biomass exhibits unstable catalytic activity due to its limited functional groups and weak resistance to interference. Therefore, further research is needed on the preparation process of biochar to improve its catalytic performance. In recent years, many researchers have loaded transition metals (Fe, Cu) and their oxides / sulfides (Fe3O4, CuO, FeS) onto biochar to further enhance its catalytic performance. Loading transition metals and their oxides / sulfides onto biochar can effectively improve the catalytic performance of biochar and reduce the leaching and aggregation of metal ions. Compared with the widely reported transition metal and oxide@biochar composites, there are relatively few reports on the activation of PS by transition metal sulfide@biochar composites. Studies have confirmed that S species can effectively promote the cycling rate between transition metals and increase the activation rate of PS by transition metals. In addition, low-valence S species have excellent electron-donating ability and may act as potential electron donors in PS activation. Besides metal loading, heteroatom (N, S, B) doping is also an important method to improve the catalytic performance of biochar. Among them, N has been extensively studied due to its extremely high electronegativity. N doping can increase the basicity of the carbon surface, enhance its affinity for PS, and change the electronic structure of carbon materials, thereby increasing the electron transfer rate and improving the catalytic activity of carbon materials. Currently, there are no reports on using biochar materials to load CuS as catalysts for the degradation of organic pollutants. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a nitrogen-doped biochar-supported copper sulfide composite material, its preparation method, and its application. Using wheat straw and urea as raw materials, this invention prepares a nitrogen-doped biochar (NBC)-supported copper sulfide (CuS) composite material (CuSNBC) via a pyrolysis-coprecipitation method. This composite material is then applied to activated persulfate (PDS) to degrade the azo dye Orange G (OG) in water. The preparation method of this invention achieves both the resource utilization of wheat straw and the efficient removal of dye from water, thus achieving the goal of treating pollution from waste. Furthermore, the catalytic material in this invention is simple to prepare, uses inexpensive raw materials, and is easily industrialized. This method offers high organic matter removal efficiency, is easy to store, transport, and add, and is applicable to a wide pH range of wastewater, demonstrating significant potential and broad application prospects in the field of dye wastewater treatment.

[0007] This invention is achieved through the following technical solution:

[0008] The first objective of this invention is to provide a nitrogen-doped biochar-supported copper sulfide composite material, the composite material comprising nitrogen-doped biochar and copper sulfide supported on the surface and pores of the nitrogen-doped biochar.

[0009] In one embodiment of the present invention, the mass ratio of the nitrogen-doped biochar to the copper sulfide is 10:1-5:1; specifically, it is 10:1-9:1, 9:1-8:1, 8:1-7:1, 7:1-6:1 and 6:1-5:1; for example, it varies from 10:1, 9:1, 8:1, 7:1, 6:1 and 5:1.

[0010] The second objective of this invention is to provide a method for preparing a nitrogen-doped biochar-supported copper sulfide composite material, comprising the following steps:

[0011] Straw powder was mixed with a nitrogen source and heated to 800℃-900℃ for 2 hours for pyrolysis. The product obtained from pyrolysis was washed with deionized water 3-4 times, dried at 80℃ for 12 hours, thoroughly ground, and passed through a 200-mesh sieve to obtain nitrogen-doped biochar.

[0012] The obtained nitrogen-doped biochar was mixed and stirred with a copper source, a sulfur source was added and stirring continued, then washed, dried, ground, and passed through a 200-mesh sieve to obtain the nitrogen-doped biochar-supported copper sulfide composite material.

[0013] In one embodiment of the present invention, the straw powder is obtained by pretreatment using the following method:

[0014] The straw is washed with water, dried, cut into sections, crushed, and sieved through a 100-mesh sieve to obtain straw powder.

[0015] In one embodiment of the present invention, the heating rate is 10°C / min to 15°C / min.

[0016] In one embodiment of the present invention, the persulfate is selected from permonosulfate and / or perdisulfate.

[0017] In one embodiment of the present invention, the mass ratio of the straw powder to the nitrogen source is 1:1 to 1:3.

[0018] In one embodiment of the present invention, the nitrogen source includes one or more of urea, melamine and ammonia.

[0019] In one embodiment of the present invention, the copper source is selected from copper sulfate and / or copper chloride; the sulfur source is selected from sodium sulfide nonahydrate and / or thiourea.

[0020] A third objective of this invention is to provide the application of the nitrogen-doped biochar-supported copper sulfide composite material in the treatment of organic pollutants.

[0021] In one embodiment of the present invention, the organic pollutant is one or more of the following: azo dye Orange G, Congo Red, and tetracycline hydrochloride.

[0022] In one embodiment of the present invention, the method of application is as follows:

[0023] Nitrogen-doped biochar-supported copper sulfide composite material was mixed with persulfate and added to organic pollutants to achieve the degradation of organic pollutants.

[0024] In one embodiment of the present invention, the pH value of the organic pollutant is 5-9; specifically, the pH value of the organic pollutant is 5-6.02, 6.02-7, and 7-9; for example, 5, 6.02, 7, and 9.

[0025] The composite material described in this invention is nitrogen-doped biochar loaded with copper sulfide, which retains the nitrogen element in the nitrogen-containing compound, enriching the types and number of active sites on the surface of the biochar. The loaded copper sulfide is a micron-sized flower-like composite.

[0026] The preparation method of the nitrogen-doped biochar-supported copper sulfide catalyst of the present invention is a simple pyrolysis-coprecipitation method.

[0027] The composite material described in this invention activates persulfate via two pathways: a non-radical pathway that generates singlet oxygen and a radical pathway that generates sulfate radicals, hydroxyl radicals, and superoxide radicals. The application shows good removal effects on both salt-free and salt-containing Orange G wastewater.

[0028] The technical solution of the present invention has the following advantages compared with the prior art:

[0029] (1) This invention provides a nitrogen-doped biochar-supported copper sulfide composite material, its preparation method and application. The nitrogen doping and copper sulfide loading solve the problems of low biochar catalytic efficiency and CuS easy agglomeration and deactivation.

[0030] (2) The nitrogen-doped biochar-supported copper sulfide composite material of the present invention is widely available and inexpensive. The synthesis method is simple and non-toxic, and it can be mass-produced. The process is ready to use and meets the actual production needs.

[0031] (3) The nitrogen-doped biochar-supported copper sulfide composite material of the present invention can efficiently activate persulfate in a wider pH range (5-9).

[0032] (4) The method of the present invention uses singlet oxygen as a medium and the combined action of multiple free radicals to achieve the degradation of organic pollutants, which is not easily affected by water quality characteristics. Attached Figure Description

[0033] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0034] Figure 1 The above are characterization diagrams from Embodiment 1 of the present invention; wherein, (a) is the X-ray diffraction pattern of BC, NBC, and CuSNBC; and (b) is the Fourier transform infrared spectrum of BC, NBC, and CuSNBC.

[0035] Figure 2 The images shown are scanning electron microscope (SEM) images of BC, NBC, and CuSNBC in Embodiment 1 of the present invention; wherein (a) and (b) are SEM images of BC; (c) and (d) are SEM images of NBC; and (e) and (f) are SEM images of CuSNBC.

[0036] Figure 3 The following is a graph (a) showing the removal effect of biochar, nitrogen-doped biochar, copper sulfide, biochar-copper sulfide, and nitrogen-doped biochar supported on copper sulfide activated persulfate on OG in Example 2 of the present invention, and its first-order kinetic parameters (b).

[0037] Figure 4 This illustrates the effect of different pH values ​​on the removal of OG in the nitrogen-doped biochar-copper sulfide / persulfate system in Example 3 of the present invention.

[0038] Figure 5 In Embodiment 4 of the present invention, Cl - SO4 2- HCO3 - and the effect of HA on OG removal rate; where (a) is Cl - The impact on OG removal rate; (b) SO4 2- The effect on OG removal rate; (c) is HCO3 - The effect of HA on OG removal rate; (d) shows the effect of HA on OG removal rate;

[0039] Figure 6 The images show the radical quenching diagram and electron paramagnetic resonance (EPR) spectrum of the nitrogen-doped biochar-supported copper sulfide / persulfate system in Example 5 of this invention; wherein, (a) is the radical quenching diagram of the nitrogen-doped biochar-supported copper sulfide / persulfate system; (b) is the signal intensity of sulfate radicals and hydroxyl radicals in the nitrogen-doped biochar-supported copper sulfide / persulfate system; (c) is the signal intensity of superoxide radicals in the nitrogen-doped biochar-supported copper sulfide / persulfate system; and (d) is the signal intensity of singlet oxygen in the nitrogen-doped biochar-supported copper sulfide / persulfate system.

[0040] Figure 7 The graph shows the effect of activated persulfate on OG removal by nitrogen-doped biochar-supported copper sulfide composite materials prepared at different pyrolysis temperatures in Example 6 of this invention. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0042] Example 1

[0043] This embodiment provides a method for preparing nitrogen-doped biochar-supported copper sulfide composite material, the specific steps of which are as follows:

[0044] The wheat straw was washed several times with deionized water, dried, cut into small pieces, and then crushed in a pulverizer and passed through a 100-mesh sieve to obtain pre-treated straw powder, which was then stored for later use.

[0045] Pretreated straw powder and urea were thoroughly mixed at a mass ratio of 1:2. The mixture was then placed in a crucible wrapped with 3 to 4 layers of tin foil and placed in a box-type resistance furnace. The temperature was increased to 800°C at a heating rate of 10°C / min and held at that temperature for 2 hours. The mixture was then cooled to room temperature and removed. The pyrolysis product was washed 3 to 4 times with deionized water, dried in a forced-air drying oven at 80°C for 12 hours, and then thoroughly ground and passed through a 200-mesh sieve to obtain nitrogen-doped biochar (NBC).

[0046] Add 100 mL of deionized water to a 200 mL Erlenmeyer flask, then add 7.8 mL of copper sulfate solution (100 g / L). Stir the mixture at 600 r / min for 30 min using a magnetic stirrer. Add 2 g of NBC and continue stirring for 2 h. Then add 7.5 mL of sodium sulfide nonahydrate solution (100 g / L) and continue stirring for 6 h. Finally, wash, dry, and grind the resulting black solid through a 200-mesh sieve to obtain nitrogen-doped biochar-supported copper sulfide composite material (CuSNBC).

[0047] Figure 1 The following are characterization diagrams from Example 1 of the present invention; wherein, (a) is the X-ray diffraction pattern of BC, NBC, and CuSNBC, which proves that copper sulfide was successfully loaded into nitrogen-doped biochar; (b) is the Fourier transform infrared spectrum of BC, NBC, and CuSNBC, which proves that CuSNBC has abundant oxygen-containing functional groups and confirms the successful doping of N and the successful loading of CuS.

[0048] Figure 2The images show scanning electron microscope (SEM) spectra of BC, NBC, and CuSNBC in this invention. They demonstrate that nitrogen doping alters the morphology of the biochar material. Furthermore, copper sulfide, a flower-like substance, was successfully loaded onto the surface and pores of the nitrogen-doped biochar.

[0049] Example 2

[0050] This embodiment provides the application of the nitrogen-doped biochar-supported copper sulfide composite material prepared in Example 1 in organic pollutants. The specific steps are as follows:

[0051] The reaction in this embodiment was carried out at a temperature of 25°C and a shaking speed of 150 r / min. 100 mL of OG solution (concentration of 50 mg / L) was added to each of five 200 mL Erlenmeyer flasks. First, 0.2 g / L of biochar, nitrogen-doped biochar, copper sulfide, biochar-copper sulfide composite material, and nitrogen-doped biochar-supported copper sulfide composite material were added for pre-adsorption for 30 min to reach adsorption equilibrium. Then, 4 mM PDS was added for catalytic degradation experiments. At 0 min, 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min, 3 mL of solution was taken using a syringe, filtered through a 0.45 μm filter membrane, and the absorbance was measured at the maximum absorption wavelength of Orange G (475 nm) using a UV spectrophotometer. The concentration was calculated based on the standard curve of Orange G.

[0052] Figure 3 This diagram shows the removal efficiency and first-order kinetic parameters of OG by biochar, nitrogen-doped biochar, copper sulfide, biochar-copper sulfide, and nitrogen-doped biochar-supported copper sulfide-activated persulfate, respectively. It demonstrates that the nitrogen-doped biochar-supported copper sulfide / persulfate system has a highly efficient OG removal effect. Figure 3 It can be seen that the CuSNBC / PDS system exhibits the best removal efficiency for OG. The first-order reaction kinetic parameter k of the CuSNBC / PDS system... obs It is 0.0793 min. -1 It is the NBC / PDS system (k obs =0.0039 min -1 20 times that of the CuS / PDS system (kobs=0.0015 min) and the CuS / PDS system (kobs=0.0015 min) -1 It is 53 times that of OG, and can remove 99.41% of OG in a cumulative 90 minutes.

[0053] Example 3

[0054] This embodiment demonstrates the effect of different pH values ​​on the removal of OG in a nitrogen-doped biochar-supported copper sulfide / persulfate system. The specific steps are as follows:

[0055] The reaction in this embodiment was carried out at a temperature of 25°C and a shaking speed of 150 r / min. First, 100 mL of OG solution (concentration 50 mg / L) was added to each 200 mL Erlenmeyer flask. The pH values ​​were adjusted to 3, 5, 7, 9, and 11 using sulfuric acid and 1 mol / L potassium hydroxide solution, respectively. 0.2 g / L of nitrogen-doped biochar-supported copper sulfide composite material was added for pre-adsorption for 30 min to reach adsorption equilibrium. Then, 4 mM PDS was added for catalytic degradation experiments to investigate the effect of solution pH on the removal of OG in the nitrogen-doped biochar-supported copper sulfide composite material / PDS system. The OG removal rate reached a maximum of 99.41% within the pH range of 6.02-9, with the original OG solution having a pH of 6.02.

[0056] Figure 4 This invention investigates the effect of different pH values ​​on the removal of OG by a nitrogen-doped biochar-copper sulfide / persulfate system; it demonstrates that within a pH range of 5-9, the nitrogen-doped biochar-supported copper sulfide / persulfate system exhibits highly efficient OG removal.

[0057] Example 4

[0058] This embodiment investigates the removal of orange-yellow G by coexisting anions and humic acid in a nitrogen-doped biochar-supported copper sulfide composite / PDS system. The specific steps are as follows:

[0059] The reaction in this embodiment was carried out at a temperature of 25°C and a shaking speed of 150 r / min. 100 mL of OG solution (concentration of 50 mg / L) was added to a 200 mL Erlenmeyer flask. KCl, K2SO4, and KHCO3 at concentrations of 5 mM, 10 mM, 20 mM, and 40 mM, and humic acid (HA) at concentrations of 5 mg / L, 10 mg / L, 20 mg / L, and 40 mg / L, were added respectively. Then, 0.2 g / L of nitrogen-doped biochar-supported copper sulfide composite material was added for pre-adsorption for 30 min to reach adsorption equilibrium. Then, 4 mM of PDS was added for catalytic degradation experiments to investigate the effects of coexisting anions and humic acid in the nitrogen-doped biochar-supported copper sulfide composite material / PDS system on the removal of orange-yellow G.

[0060] from Figure 5 As can be seen from (a) and (b) in the figure, KCl and K2SO4 have almost no effect on the removal rate of OG. Figure 5 (c) It can be seen that the removal rate of OG decreases significantly when KHCO3 is added, and the removal rate of OG increases with the increase of KHCO3 concentration. Figure 5(d) It can be seen that humic acid (HA) has an inhibitory effect on the degradation and adsorption of OG, and the inhibitory effect increases significantly with increasing HA concentration. In summary, HCO3- - Both HA and Cl have an inhibitory effect on the removal of OG, while HA has an inhibitory effect on the removal of OG - and SO4 2- It has almost no impact on the removal of OG.

[0061] Example 5

[0062] This embodiment provides free radical quenching and electron paramagnetic resonance (EPR) tests for a nitrogen-doped biochar-supported copper sulfide / persulfate system. The specific steps are as follows:

[0063] In this embodiment, the free radical quenching experiment was conducted at a reaction temperature of 25°C and a shaking speed of 150 r / min. 100 mL of OG solution (concentration 50 mg / L) was added to a 200 mL Erlenmeyer flask, and 100 mM methanol (MeOH) was added to quench ·OH and SO4· - Quenching of ·OH with 100 mM tert-butanol (TBA) and quenching of O2 with 10 mM p-benzoquinone (p-BQ) - Quenching with 10 mM furfural (FFA) 1 O2 was added, followed by pre-adsorption of 0.2 g / L nitrogen-doped biochar-supported copper sulfide composite material for 30 min to reach adsorption equilibrium. Then, 4 mM PDS was added for catalytic degradation experiments to investigate the types and contributions of free radicals in the nitrogen-doped biochar-supported copper sulfide composite material / PDS system. Electron paramagnetic resonance (EPR) analysis used 0.1 mol / L 5,5-dimethyl-1-pytroline N-oxide (DMPO) and 4-amino-2,2,6,6-tetramethylpipenidine (TEMP) as spin traps to capture free radicals and non-free radical singlet oxygen in the reaction system. 0.2 g / L CuSNBC and PDS were added to the reaction solvent and reacted for 5 min and 15 min, respectively. 50 μL of the sample was then mixed thoroughly with 50 μL of DMPO / TEMP. ·OH and SO4· - The solvent in the reaction system is water, O2· - The reaction system uses methanol as the solvent, which is non-radical. 1 The solvent in the O2 reaction system is water. The EPR instrument is used to detect the signal of the spin-captured adduct, and the type of active substance in the reaction system is determined based on the corresponding signal.

[0064] Figure 6These are the radical quenching diagrams and electron paramagnetic resonance spectra of the nitrogen-doped biochar-supported copper sulfide / persulfate system in this invention. They demonstrate that the nitrogen-doped biochar-supported copper sulfide / persulfate system can generate non-radical pathways such as singlet oxygen and radical pathways such as sulfate radicals, hydroxyl radicals, and superoxide radicals, which jointly participate in the degradation of Orange G. Among them, superoxide radicals and singlet oxygen play the main roles in the degradation of Orange G.

[0065] Example 6

[0066] This embodiment demonstrates the effect of different pyrolysis temperatures on the removal of OG in a nitrogen-doped biochar-supported copper sulfide / persulfate system. The specific steps are as follows:

[0067] The reaction in this embodiment was carried out at a temperature of 25°C and a shaking speed of 150 r / min. 100 mL of OG solution (concentration of 50 mg / L) was added to three 200 mL Erlenmeyer flasks. First, 0.2 g / L of nitrogen-doped biochar-supported copper sulfide composite material prepared at pyrolysis temperatures of 400°C, 600°C, and 800°C was added for pre-adsorption for 30 min to reach adsorption equilibrium. Then, 4 mM PDS was added for catalytic degradation experiments. At 0 min, 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min, 3 mL of solution was taken using a syringe, filtered through a 0.45 μm filter membrane, and the absorbance was measured using a UV spectrophotometer at the maximum absorption wavelength of Orange G (475 nm). The concentration was calculated based on the standard curve of Orange G.

[0068] Figure 7 The figures show the removal effects of activated persulfate on OG by nitrogen-doped biochar-supported copper sulfide composite materials prepared at pyrolysis temperatures of 400℃, 600℃, and 800℃ in this invention. This demonstrates that the nitrogen-doped biochar-supported copper sulfide / persulfate system prepared at a pyrolysis temperature of 800℃ has a high efficiency in removing OG.

[0069] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. The application of a nitrogen-doped biochar-supported copper sulfide composite material in the treatment of organic pollutants, characterized in that, The composite material includes nitrogen-doped biochar and copper sulfide loaded on the surface and pores of the nitrogen-doped biochar. The preparation method of the nitrogen-doped biochar-supported copper sulfide composite material includes the following steps: Straw powder is mixed with a nitrogen source and heated to 800℃-900℃ for pyrolysis to obtain nitrogen-doped biochar; The obtained nitrogen-doped biochar was mixed and stirred with a copper source, and a sulfur source was added and stirring continued to obtain the nitrogen-doped biochar-supported copper sulfide composite material. The organic pollutant is one or more of the following: azo dye Orange G, Congo Red, and tetracycline hydrochloride. The method of application is as follows: Nitrogen-doped biochar-supported copper sulfide composite material was mixed with persulfate and added to organic pollutants to achieve the degradation of organic pollutants.

2. The application according to claim 1, characterized in that, The mass ratio of the nitrogen-doped biochar to the copper sulfide is 10:1 to 5:

1.

3. The application according to claim 1, characterized in that, The mass ratio of straw powder to nitrogen source is 1:1 to 1:

3.

4. The application according to claim 1, characterized in that, The nitrogen source includes one or more of urea, melamine, and ammonia.

5. The application according to claim 1, characterized in that, The copper source is selected from copper sulfate and / or copper chloride; the sulfur source is selected from sodium sulfide nonahydrate and / or thiourea.

6. The application according to claim 1, characterized in that, The pH value of the organic pollutant is 5-9.

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