Nanometer zero-valent iron core-shell composite material regulated and controlled by solid-state phase change of oxygen-containing group and preparation method and application of nanometer zero-valent iron core-shell composite material

Abstract

The invention discloses a nano zero-valent iron core-shell composite material regulated and controlled by solid-state phase change of oxygen-containing groups as well as a preparation method and application of the nano zero-valent iron core-shell composite material, and belongs to the field of treatment of new pollutants in organic wastewater. The method comprises the following steps: co-dissolving biomass carbon, a metal iron source and an oxygen-containing functional group additive in deionized water, carrying out stirring reaction at room temperature, and then centrifugally collecting precipitate; carrying out vacuum drying on the obtained precipitate to obtain an iron-based precursor; under an inert atmosphere, roasting the iron-based precursor to 600-900 DEG C at a heating rate of 2-10 DEG C / min, and keeping the temperature for 2-4 hours to obtain black magnetic powder; and stirring and etching the black magnetic powder in an acid solution with the pH value of 1-3 for 1-2 hours, and drying to obtain the nano zero-valent iron-based material with the core-shell structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of new pollutants treatment of organic wastewater, and particularly relates to a nano zero-valent iron core-shell composite material using oxygen-containing group solid phase change regulation and a preparation method and application thereof. BACKGROUND

[0002] As a key drug in medical and agricultural production, the large-scale use of antibiotics has led to increasingly serious environmental residue problems. In particular, the illegal discharge of pharmaceutical wastewater and the overuse of antibiotics in the agricultural field have caused the continuous increase of antibiotic concentrations in surface water, groundwater, and even soil. Such new pollutants have the risk of biological accumulation and drug resistance gene induction, posing a major threat to the ecosystem and human health. For the treatment of antibiotic pollution, advanced oxidation technology is considered an effective means due to its high mineralization capacity. The activation and degradation technology of persulfate salt has attracted much attention due to its high oxidation potential and wide pH applicability, and transition metal catalysts play a key role in this process. Nano zero-valent iron (nZVI) has shown significant potential in activating persulfate salt to degrade organic pollutants due to its high specific surface area, strong reducing property, and abundant surface active sites. However, the large-scale application of traditional nZVI faces multiple technical bottlenecks. First, the mainstream carbon thermal reduction method requires high-temperature reduction at ≥900℃, which not only increases production costs but also causes iron particles to melt and aggregate, resulting in a sharp decrease in specific surface area and loss of active sites. In addition, high-temperature reduction easily produces intermediate products such as FeO and Fe3O4 due to kinetic limitations, leading to incomplete reduction of zero-valent iron. Second, traditional nZVI has a single iron core structure, which directly exposes the iron core to an oxidizing environment during the catalytic process, leading to rapid oxidation passivation and a large amount of iron ion dissolution (which can exceed 50 mg / L), which not only reduces the stability of the material and causes the cycle performance to deteriorate, but also causes secondary pollution of water bodies. In addition, the lack of an electron transfer channel in the single structure restricts the activation efficiency of persulfate salt. To improve the above defects, existing technologies have tried two paths: one is to introduce a chemical reducing agent such as sodium borohydride for liquid-phase reduction to prepare nZVI, but sodium borohydride is expensive and the reaction is violent and difficult to control. The resulting particles have a wide particle size distribution and low uniformity, and more seriously, the introduction of residual boron elements introduces new environmental risks. The second is to use a carrier loading strategy (such as activated carbon and biochar), which can alleviate the problem of aggregation, but the specific surface area of the carrier is insufficient (usually <1000 m 2 / g) and pore structure disorder, resulting in low iron dispersion, poor accessibility of active sites, and weak interface binding between the carrier and iron, which cannot inhibit the oxidation leaching, and the material still has 20%-30% iron loss in continuous use. Therefore, the current nZVI material and its preparation technology generally exist four contradictions: the contradiction between high-temperature synthesis and energy consumption control, the contradiction between high activity and low stability, the contradiction between structural simplicity and functional diversity, and the contradiction between pollution control process and secondary pollution risk. It is urgent to develop a low-temperature and high-efficiency, structure-controllable and strong-stability nZVI preparation method to break through the technical bottleneck in the field of environmental remediation. SUMMARY

[0003] The technical problem solved by the present application is that the traditional carbon thermal synthesis of nZVI generally requires high-temperature carbonization (≥900℃), which is high in energy consumption and easy to cause nanoparticle agglomeration, incomplete reduction and structural simplicity, especially in the problems of serious iron leaching and poor stability in the catalytic degradation of new pollution complex environment, a carbon-supported Fe 0 Composite core-shell material, preparation method and application thereof. The problem of high activity accompanied by low stability in the preparation of zero-valent nano-iron composite material is solved, and a new paradigm is provided for the catalytic application of transition metal nanomaterials.

[0004] Technical scheme: A preparation method of a nano zero-valent iron core-shell composite material using oxygen-containing functional group solid phase transformation regulation, comprising the following steps: (1) dissolving biomass carbon, metal iron source and oxygen-containing functional group additive in deionized water, stirring at room temperature, and then collecting the precipitate by centrifugation; (2) vacuum drying the precipitate obtained in step (1) to obtain an iron-based precursor; (3) under an inert atmosphere, the iron-based precursor is calcined to 600-900℃ at a heating rate of 2-10℃ / min, and is kept for 2-4 hours to obtain a black magnetic powder; (4) the black magnetic powder is stirred and etched in an acidic solution with pH=1-3 for 1-2 hours, and is dried to obtain a nano zero-valent iron-based material (Fe 0 @Fe2O3@Fe3C).

[0005] The metal iron source is ferric chloride hexahydrate or ferric nitrate nonahydrate; the oxygen-containing functional group additive is at least one selected from sodium nitrite, sodium nitrate, sodium carbonate or urea; and the biomass carbon is sugarcane residue.

[0006] In step (1), the mass ratio of the biomass carbon to the metal iron source is 2:1-1:2.9.

[0007] In step (1), the molar ratio of the metal iron source to the oxygen-containing functional group additive is 1:0.001-1:0.013.

[0008] The stirring reaction condition of step (1) is: rotation speed 300-600 rpm, time 12-24 hours; the centrifugal condition is: rotation speed 3000-6000 rpm, time 10-30 minutes.

[0009] The vacuum drying condition of step (2) is: temperature 50-65 DEG C, time 12-48 hours.

[0010] The inert atmosphere in step (3) is nitrogen or argon atmosphere.

[0011] The drying condition in step (4) is: temperature 50-60 DEG C, time 2-5 hours.

[0012] The above method prepares the core-shell structure nanometer zero-valent iron-based material Fe 0 @Fe2O3@Fe3C.

[0013] The above core-shell structure nanometer zero-valent iron-based material is applied to catalytic peroxymonosulfate degradation of organic pollutants, and the organic pollutants include antibiotic new pollutants.

[0014] Beneficial effect: the core-shell structure zero-valent iron nanomaterial (Fe 0 @Fe2O3@Fe3C) prepared by the micro-oxygen environment regulation strategy of the application has made breakthrough progress in the synergistic optimization of low-temperature carbon thermal reduction preparation and high-efficiency degradation performance, and the core beneficial effects can be summarized as the following four aspects: (1) the introduction of oxygen-containing additives realizes the synthesis of Fe 0 at a lower temperature based on the synergistic effect of solid phase change dynamics (diffusion control phase separation) and surface interface engineering (interface oxygen passivation); (2) through the micro-oxygen atmosphere regulation, the one-step formation of Fe 0 core, Fe2O3 interface layer and Fe3C shell is realized, which enriches the active sites of the catalytic system, accelerates the electron transfer rate, and realizes the efficient degradation of new pollutants; (3) the core-shell structure of Fe 0 @Fe2O3@Fe3C, the intermediate iron oxide layer acts as a diffusion barrier to inhibit the aggregation and oxidation of the zero-valent iron core, while providing oxygen vacancies to promote the generation of oxygen-based radicals; (4) the metallic Fe3C shell provides a high migration rate path, and the surface electron-deficient state (Fe3C δ+ ) can stably adsorb PMS molecules and accelerate the generation of singlet oxygen ( 1 O2). BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is the transmission electron microscope graph of the prepared double-shell nanometer zero-valent iron composite material.

[0016] Figure 2is a degradation curve of norfloxacin simulated wastewater by different iron source catalysts for activating potassium peroxymonosulfate.

[0017] Figure 3 is a degradation curve of norfloxacin simulated wastewater by different oxygen-containing group additive ratio composites.

[0018] Figure 4 is a degradation curve of norfloxacin simulated wastewater by different oxygen-containing group additive synthesis composites.

[0019] Figure 5 is a degradation curve of norfloxacin simulated wastewater by different carbon thermal temperatures.

[0020] Figure 6 is a degradation curve of norfloxacin simulated wastewater by different degradation systems. DETAILED DESCRIPTION

[0021] Example 1 In this embodiment, the core-shell iron-based composite Fe 0 The specific preparation method of the Fe2O3@Fe3C catalytic material is as follows: (1) 3.24 g of FeCl3·6H2O, 1.12 g of sugarcane residue, and 0.0011 g of sodium nitrite were added to 20 mL of deionized water, and the obtained mixture solution was stirred at room temperature at 500 rpm for 24 hours, and then the precipitate was collected by centrifugation at 5000 rpm for 10 minutes.

[0022] (2) The iron-based precursor obtained in step 1) was vacuum dried at 65°C for 24 hours.

[0023] (3) The temperature was raised to 700°C at a rate of 5°C / min in a nitrogen or inert gas atmosphere, and calcined for 3 hours to obtain a black magnetic powder.

[0024] (4) Stirring at room temperature for 1.5 h in a solution with pH = 3, and drying in an oven at 60°C for 3 h to obtain a nano zero-valent iron core-shell composite (Fe 0 @ Fe2O3@Fe3C).

[0025] (5) 0.2 g of PMS was measured and added to 20 mL of deionized water, and was recorded as solution A.

[0026] The prepared nano zero-valent iron core-shell composite (Fe 0 @ Fe2O3@Fe3C) catalyst was used for the removal of antibiotics in water pollution, and the NOR in the simulated wastewater was 5 mg / L.

[0027] The catalyst was added as follows: 100 mL of 5 mg / L norfloxacin simulated pollutants was added to a 250 mL beaker, and then 0.02 g of Fe 0 @ Fe2O3@Fe3C catalyst was added, 2 mL of solution A, stirred at 300 rpm at room temperature (20±2℃), and water samples were taken every certain time to measure the effect of norfloxacin at 273 nm by ultraviolet spectrophotometry. The degradation curve reached 88.6%, as shown in Figure 1 .

[0028] Example 2 In this example, the core-shell iron-based composite material Fe 0 @ Fe2O3@Fe3C was prepared as follows: (1) 3.24 g of Fe(NO3)3·9H2O, 1.12 g of sugarcane residue, and 0.0076 g of sodium nitrite were added to 20 mL of deionized water, and the resulting mixture solution was stirred at 500 rpm for 24 hours at room temperature, and then the precipitate was collected by centrifugation at 5000 rpm for 10 minutes.

[0029] (2) The iron-based precursor obtained in step 1) was vacuum dried at 65℃ for 24 hours.

[0030] (3) The temperature was raised to 700℃ at a rate of 5℃ / min in a nitrogen or inert gas atmosphere, and calcined for 3 hours to obtain a black magnetic powder.

[0031] (4) Stirring at room temperature for 1.5 h in a solution with pH=3, and drying in an oven at 60℃ for 3 h to obtain the nano zero-valent iron core-shell composite material (Fe 0 @ Fe2O3@Fe3C).

[0032] (5) 0.2 g of PMS was measured and added to 20 mL of deionized water, and was recorded as solution A.

[0033] The prepared nano zero-valent iron core-shell composite material (Fe 0 @ Fe2O3@Fe3C) was used to remove antibiotics in water pollution, and the NOR in the simulated wastewater was 5 mg / L.

[0034] The catalyst was added as follows: 100 mL of 5 mg / L norfloxacin simulated pollutants was added to a 250 mL beaker, and then 0.02 g of Fe 0 @ Fe2O3@Fe3C catalyst was added, 2 mL of solution A, stirred at 300 rpm at room temperature (20±2℃), and water samples were taken every certain time to measure the effect of norfloxacin at 273 nm by ultraviolet spectrophotometry. The degradation curve reached 88.6%, as shown in Figure 2 .

[0035] Example 3 (optimization of the proportion of oxygen-containing group assistants) In this example, the core-shell iron-based composite material Fe 0 The specific preparation method of the Fe2O3@Fe3C catalytic material is as follows: (1) 3.24 g of Fe(NO3)3·9H2O and 1.12 g of sugarcane residue were added to 0.00069, 0.0034, 0.0076, and 0.0089 g of sodium nitrite, respectively, in 20 mL of deionized water. The resulting mixture solution was stirred at 500 rpm for 24 hours at room temperature, and then the precipitate was collected by centrifugation at 5000 rpm for 10 minutes.

[0036] (2) The iron-based precursor obtained in step 1) was vacuum dried at 65°C for 24 hours.

[0037] (3) The temperature was raised to 700°C at a rate of 5°C / min in a nitrogen or inert gas atmosphere, and calcination was performed for 3 hours to obtain a black magnetic powder.

[0038] (4) The mixture was stirred at room temperature for 1.5 hours in a solution with a pH of 3, and then dried in an oven at 60°C for 3 hours to obtain a nano zero-valent iron core-shell composite material (Fe 0 @ Fe2O3@Fe3C).

[0039] (5) 0.2 g of PMS was measured and added to 20 mL of deionized water, and the resulting solution was labeled as solution A.

[0040] The prepared nano zero-valent iron core-shell composite material (Fe 0 @ Fe2O3@Fe3C) was used as a catalyst for the removal of antibiotics in water pollution, and the NOR in the simulated wastewater was 5 mg / L.

[0041] The catalyst was added as follows: 100 mL of 5 mg / L norfloxacin simulated pollutants were added to four 250 mL beakers, and then 0.02 g of catalyst and 2 mL of solution A were added to each beaker. The mixture was stirred at 300 rpm at room temperature (20±2°C), and water samples were taken every certain time to measure the effect of norfloxacin at 273 nm by ultraviolet spectrophotometry. The degradation curves are shown in Figure 3

[0042] Example 4 (optimization of the type of oxygen-containing functional group assistants) In this example, the core-shell iron-based composite material Fe 0 @Fe2O3@Fe3C catalytic material was prepared as follows: ​(1) 3.24 g Fe(N03)3-9H20 and 1.12 g of bagasse were added into 20 mL of deionized water, respectively, with the addition of equal molar ratio of sodium nitrate, sodium carbonate and urea, and equal molar oxygen of sodium nitrate and sodium nitrite mixed additives. The obtained mixture solution was stirred at 500 rpm for 24 hours at room temperature, and then the precipitate was collected by centrifugation at 5000 rpm for 10 minutes.

[0043] (2) The iron-based precursor obtained in step 1) was vacuum dried at 65°C for 24 hours.

[0044] (3) The temperature was raised to 700°C at 5°C / min under nitrogen or inert gas atmosphere, and calcined for 3 hours to obtain black magnetic powder.

[0045] (4) The nanometer zero-valent iron core-shell composite material was obtained by stirring in a solution with pH = 3 at room temperature for 1.5 hours and drying in an oven at 60°C for 3 hours.

[0046] (5) 0.2 g of PMS was measured and added into 20 mL of deionized water, which was recorded as solution A.

[0047] The prepared nanometer zero-valent iron core-shell composite material (Fe 0 @ Fe203@ Fe3C) catalyst was used for the removal of antibiotics in water pollution, and the NOR in the simulated wastewater was 5 mg / L.

[0048] The catalyst was added as follows: 100 mL of 5 mg / L norfloxacin simulated pollutants were added into four 250 mL beakers, and then 0.02 g of catalyst and 2 mL of solution A were added, respectively. The mixture was stirred at 300 rpm at room temperature (20±2°C), and water samples were taken every certain time to measure the effect of norfloxacin at 273 nm by ultraviolet spectrophotometer. The degradation curves are shown in Figure 4

[0049] Example 5 (carbon heat temperature optimization) In this example, the core-shell iron-based composite material Fe 0 @ Fe203@ Fe3C catalyst material was prepared as follows: (1) 3.24 g Fe(N03)3-9H20, 1.12 g of bagasse and 0.0076 g of sodium nitrite were added into 20 mL of deionized water, and the obtained mixture solution was stirred at 500 rpm for 24 hours at room temperature, and then the precipitate was collected by centrifugation at 5000 rpm for 10 minutes.

[0050] (2) The iron-based precursor obtained in step 1) was vacuum dried at 65°C for 24 hours.

[0051] ​(3) Temperature was raised to 600, 700, 800 and 900℃ at 5℃ / min in nitrogen or inert gas atmosphere, and calcined for 3 hours to obtain black magnetic powder.

[0052] (4) In the solution with pH=3, stirring was carried out at room temperature for 1.5 hours, and drying was carried out in an oven at 60℃ for 3 hours to obtain the nano zero-valent iron core-shell composite material (Fe 0 @ Fe2O3@Fe3C).

[0053] (5) 0.2g of PMS was measured and added into 20mL of deionized water, and recorded as solution A.

[0054] The prepared nano zero-valent iron core-shell composite material (Fe 0 @ Fe2O3@Fe3C) catalyst was used for removal of antibiotics in water pollution, and NOR in simulated wastewater was 5 mg / L.

[0055] The catalyst was added as follows: 100mL of 5 mg / L norfloxacin simulated pollutants were added into four 250mL beakers, respectively, and then 0.02g of catalyst and 2mL of solution A were added into each beaker, and stirring was carried out at room temperature (20±2℃) at 300rpm, and water samples were taken every certain time to measure norfloxacin effect at 273nm by ultraviolet spectrophotometer, and the degradation curves were as shown in Figure 5

[0056] Comparative Example 1: (without oxygen-containing group additive) The specific preparation method of the iron-based composite material catalyst is as follows: (1) 3.24g of Fe(NO3)3·9H2O and 1.12g of sugarcane residue were added into 20mL of deionized water, and the obtained mixture solution was stirred at 500rpm at room temperature for 24 hours, and then the precipitate was collected by centrifugation at 5000rpm for 10 minutes.

[0057] (2) The iron-based precursor obtained in step 1) was vacuum dried at 60℃ for 24 hours.

[0058] (3) Temperature was raised to 700℃ at 10℃ / min in nitrogen or inert gas atmosphere, and calcined for 3 hours to obtain black powder.

[0059] (4) In the solution with pH=3, stirring was carried out at room temperature for 1.5 hours, and drying was carried out in an oven at 60℃ for 3 hours to obtain the iron-based composite material (Fe / BC-700).

[0060] (5) 0.2g of PMS was measured and added into 20mL of deionized water, and recorded as solution A.

[0061] ​The prepared iron-based composite material catalyst is used for removal of antibiotics in water pollution, and the NOR in the simulated wastewater is 5 mg / L.

[0062] The catalyst is added as follows: 100 mL of 5 mg / L norfloxacin simulated pollutants is added to a 250 mL beaker, and then 0.02 g of Fe / BC-700 and 2 mL of solution A are added respectively, and stirred at 300 rpm at room temperature (20±2℃), and water samples are taken every certain time to measure the effect of norfloxacin at 273 nm by ultraviolet spectrophotometer. The degradation curve is shown in Figure 6 .

[0063] Comparative Example 2: (without iron source) The specific preparation method of the carbon-based composite material catalyst is as follows: (1) 1.12 g of sugarcane residue and 0.0076 g of sodium nitrite are added to 20 mL of deionized water, and the obtained mixture solution is stirred at 500 rpm at room temperature for 24 hours, and then the precipitate is collected by centrifugation at 5000 rpm for 10 minutes.

[0064] (2) The iron-based precursor obtained in step 1) is vacuum dried at 60℃ for 24 hours.

[0065] (3) Under the atmosphere of nitrogen or inert gas, the temperature is increased to 700℃ at 10℃ / min respectively, and calcined for 3 hours to obtain black powder.

[0066] (4) Stirring at room temperature for 1.5 h in a solution with pH=3, and drying in an oven at 60℃ for 3 h to obtain the iron-based composite material (BC-700).

[0067] (5) 0.2 g of PMS is measured and added to 20 mL of deionized water, and is recorded as solution A.

[0068] The prepared iron-based composite material catalyst is used for removal of antibiotics in water pollution, and the NOR in the simulated wastewater is 5 mg / L.

[0069] The catalyst is added as follows: 100 mL of 5 mg / L norfloxacin simulated pollutants is added to a 250 mL beaker, and then 0.02 g of Fe / BC-700 and 2 mL of solution A are added respectively, and stirred at 300 rpm at room temperature (20±2℃), and water samples are taken every certain time to measure the effect of norfloxacin at 273 nm by ultraviolet spectrophotometer. The degradation curve is shown in Figure 5 .

[0070] Comparative Example 3: (sodium borohydride aid) The specific preparation method of the carbon-based composite material catalyst is as follows: (1) 3.24 g Fe(NO3)3·9H2O, 1.12 g sugarcane bagasse and 0.0042 g sodium borohydride were added to 20 mL of deionized water. The resulting mixture was stirred at 500 rpm for 24 hours at room temperature, and then the precipitate was collected by centrifugation at 5000 rpm for 10 minutes.

[0071] (2) The iron-based precursor obtained in step 1) was vacuum dried at 60°C for 24 hours.

[0072] (3) In a nitrogen or inert gas atmosphere, the temperature is increased to 700°C at 10°C / min and calcined for 3 hours to obtain a black powder.

[0073] (4) In a solution with pH=3, the mixture was stirred at room temperature for 1.5 h and dried in an oven at 60℃ for 3 h to obtain an iron-based composite material (Fe). 0 / BC-700).

[0074] (5) Measure 0.2g of PMS and add it to 20mL of deionized water, and record it as solution A.

[0075] The prepared iron-based composite catalyst was used to remove antibiotics from water pollution, with a simulated NOR of 5 mg / L in the wastewater.

[0076] The catalyst was added as follows: 100 mL of 5 mg / L norfloxacin simulated pollutant was added to a 250 mL beaker, followed by the addition of 0.02 g of Fe. 0 / BC-700, 2 mL of solution A, was stirred at 300 rpm at room temperature (20±2℃). Water samples were taken at regular intervals and measured at 273 nm using a UV spectrophotometer. The norfloxacin effect reached 75.2%, and its degradation curve is shown in the figure. Figure 6 As shown.

[0077] Compare with Example 4: (without PMS system) The specific preparation method of iron-based composite catalyst is as follows: (1) 3.24g Fe(NO3)3·9H2O, 1.12g sugarcane bagasse and 0.0076g sodium nitrite were added to 20mL of deionized water. The resulting mixture was stirred at 500 rpm for 24 hours at room temperature, and then the precipitate was collected by centrifugation at 5000 rpm for 10 minutes.

[0078] (2) The iron-based precursor obtained in step 1) was vacuum dried at 60°C for 24 hours.

[0079] (3) In a nitrogen or inert gas atmosphere, the temperature is increased to 700°C at 10°C / min and calcined for 3 hours to obtain a black powder.

[0080] (4) in the solution of pH=3, stirring at room temperature for 1.5h, drying in the oven at 60℃ for 3h, Fe 0 @ Fe2O3@Fe3C.

[0081] The prepared iron-based composite material catalyst is used for removing antibiotics in water pollution, and NOR in the simulated wastewater is 5mg / L.

[0082] The catalyst is added as follows: 100mL of 5mg / L norfloxacin simulated pollutants is added in a 250mL beaker, and then 0.02g of Fe 0 @ Fe2O3@Fe3C is added respectively, stirring at room temperature (20±2℃) at 300rpm, and water samples are taken every certain time to measure the norfloxacin effect at 273nm by ultraviolet spectrophotometer, and the degradation curve is as shown in Figure 6

[0083] The embodiments of the present application are described in detail in combination with the drawings, but the present application is not limited to the above-mentioned embodiments, and for ordinary skilled in the art, after knowing the content recorded in the present application, a number of equivalent transformations and substitutions can be made without departing from the principles of the present application, and these equivalent transformations and substitutions should be regarded as belonging to the protection scope of the present application.​

Claims

1. A method for preparing a nano zero-valent iron core-shell composite material regulated by solid phase transformation with oxygen-containing functional groups, characterized in that, The method comprises the following steps: (1) biomass carbon, metal iron source and oxygen-containing functional group additives are co-dissolved in deionized water, and the precipitate is collected after stirring reaction at room temperature and centrifugation; (2) the precipitate obtained in step (1) is vacuum dried to obtain an iron-based precursor; (3) the iron-based precursor is calcined to 600-900℃ at a heating rate of 2-10℃ / min under an inert atmosphere, and the temperature is kept for 2-4 hours to obtain a black magnetic powder; (4) the black magnetic powder is etched in an acid solution with pH=1-3 for 1-2 hours, and dried to obtain a core-shell nano zero-valent iron-based material (Fe 0 @Fe2O3@Fe3C).

2. The method of claim 1, wherein, The metal iron source is ferric chloride hexahydrate or ferric nitrate nonahydrate; the oxygen-containing functional group additive is at least one selected from sodium nitrite, sodium nitrate, sodium carbonate or urea; and the biomass carbon is sugarcane residue.

3. The method of claim 1, wherein: The mass ratio of the biomass carbon to the metal iron source in step (1) is 2:1-1:2.

9.

4. The method of claim 1, wherein: The molar ratio of the metal iron source to the oxygen-containing functional group additive in step (1) is 1:0.001-1:0.

013.

5. The method of claim 1, wherein: The stirring reaction condition of step (1) is: rotation speed 300-600 rpm, time 12-24 hours; and the centrifugation condition is: rotation speed 3000-6000 rpm, time 10-30 minutes.

6. The method of claim 1, wherein: The vacuum drying condition of step (2) is: temperature 50-65 ℃, time 12-48 hours.

7. The method of claim 1, wherein: The inert atmosphere in step (3) is a nitrogen or argon atmosphere.

8. The method of claim 1, wherein: The drying condition in step (4) is: temperature 50-60 ℃, time 2-5 hours.

9. The method according to any one of claims 1-8 yields a core-shell structured nanomaterial of zero-valent iron, Fe. 0 @Fe2O3@Fe3C.

10. Application of the core-shell structure nano zero-valent iron-based material according to claim 9 to catalytic degradation of organic pollutants by persulfate, wherein the organic pollutants include antibiotic new pollutants.

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