Gamma-alumina nanosheet supported ferrous sulfide composite material, and preparation method and application thereof

Abstract

The application discloses a kind of gamma-alumina nanosheet load ferrous disulfide composite material and its preparation method and application, belong to environmental remediation material technical field.The preparation steps of the gamma-alumina nanosheet load ferrous disulfide composite material include: in organic solvent, iron source, sulfur source and gamma-alumina nanosheet are added, after being mixed evenly, solvent hot reaction is carried out, and the obtained precipitate is the gamma-alumina nanosheet load ferrous disulfide composite material.The gamma-Al2O3 nanosheet used in the application has higher specific surface area, can provide sufficient loading site for FeS2, prevent single FeS2 from causing catalytic activity to decline due to agglomeration.The gamma-Al2O3 nanosheet used in the application contains a large number of hydroxyl functional groups on surface, can create buffer microenvironment, greatly improve the pH applicable range of FeS2, so that composite material under the condition that pH is 3~11, all show excellent oxidant activation performance, realize the efficient degradation to pollutant.

Description

Technical Field

[0001] This invention belongs to the field of environmental remediation materials technology, specifically relating to a γ-alumina nanosheet-supported ferrous disulfide composite material, its preparation method, and its application. Background Technology

[0002] Persulfate monophosphate (PMS)-based advanced oxidation technology generates sulfate radicals (SO4) with high oxidation potential. ·- PMS (Polymerase Spectrophotometer) has shown broad application prospects in the degradation and treatment of organic pollutants in water bodies. When using PMS to degrade organic pollutants in water, it is usually necessary to add a catalyst to activate PMS. Developing new catalysts that can efficiently activate PMS is a direction worthy of exploration in this field. Summary of the Invention

[0003] The purpose of this invention is to provide a γ-alumina nanosheet-supported ferrous disulfide composite material, its preparation method, and its application.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] One of the technical solutions of this invention is to provide a method for preparing a composite material of γ-alumina nanosheets supported on ferrous disulfide, comprising the following steps:

[0006] Iron source, sulfur source and γ-alumina nanosheets are added to an organic solvent, mixed evenly and then subjected to a solvothermal reaction. The resulting precipitate is the γ-alumina nanosheet-supported ferrous disulfide composite material.

[0007] This invention utilizes the favorable electronic structure and Fe(II) / Fe(III) cycling ability of FeS2 as a material for activating PMS. However, bare FeS2 is prone to particle aggregation, exhibits poor reaction stability, and is sensitive to pH conditions, severely limiting its activation efficiency and environmental adaptability. To address this, by loading FeS2 onto a γ-alumina (γ-Al2O3) support with high stability, high specific surface area, good thermal stability, and abundant surface hydroxyl groups, its dispersibility and interfacial reactivity are effectively improved. Furthermore, the nanosheet structure of γ-Al2O3 not only facilitates the formation of abundant loading sites but also modulates the interfacial microenvironment, thereby enhancing the activation performance and stability of FeS2 and expanding its application potential in PMS activation systems.

[0008] Optionally, the organic solvent includes N,N-dimethylformamide.

[0009] Preferably, the molar ratio of Fe in the iron source to S in the sulfur source is 1:2.

[0010] Preferably, the concentration of the iron source in the organic solvent is 1 mmol / L; and the concentration of the sulfur source in the organic solvent is 2 mmol / L.

[0011] Optionally, the iron source is ferric nitrate, and the sulfur source is thiourea.

[0012] Preferably, the temperature of the solvothermal reaction is 160–180°C and the time is 8–10 h.

[0013] Preferably, the process after the solvothermal reaction further includes separation, drying, and grinding steps.

[0014] Preferably, the preparation steps of the γ-alumina nanosheets include: mixing aluminum salt, potassium sulfate and urea in water, obtaining γ-AlOOH through a hydrothermal reaction, and calcining the γ-AlOOH to obtain the γ-alumina nanosheets.

[0015] More preferably, the aluminum salt is aluminum nitrate nonahydrate, wherein the mass ratio of aluminum nitrate nonahydrate, potassium sulfate and urea is 12:5:4, the concentration of aluminum nitrate nonahydrate in water is 1.2 g / L, the concentration of potassium sulfate in water is 0.5 g / L, and the concentration of urea in water is 0.4 g / L.

[0016] More preferably, the hydrothermal reaction is carried out at a temperature of 160–180°C for a duration of 6–8 hours.

[0017] More preferably, the calcination temperature is 450–500°C and the time is 2 hours.

[0018] The second technical solution of the present invention provides a γ-alumina nanosheet-supported ferrous disulfide composite material prepared according to the above-mentioned preparation method of γ-alumina nanosheet-supported ferrous disulfide composite material.

[0019] The third technical solution of the present invention provides an application of the above-mentioned γ-alumina nanosheet-supported ferrous disulfide composite material in the degradation of neonicotinoid pesticides by activated PMS.

[0020] The beneficial technical effects of the present invention are as follows:

[0021] (1) The γ-Al2O3 nanosheets used in this invention have a high specific surface area, which can provide sufficient loading sites for FeS2 and prevent the catalytic activity of single FeS2 from decreasing due to aggregation.

[0022] (2) The γ-Al2O3 nanosheets used in this invention contain a large number of hydroxyl functional groups on their surface, which can create a buffer microenvironment and greatly improve the pH range of FeS2. This allows the composite material to exhibit excellent oxidant activation performance under pH conditions of 3 to 11, thus achieving efficient degradation of pollutants.

[0023] (3) The preparation method provided by the present invention has mild reaction conditions, does not involve toxic and harmful raw materials, and the prepared catalyst is stable, efficient and environmentally friendly. It can effectively reduce the activation energy of oxidants such as persulfate and achieve efficient removal of thiamethoxam (THX). Attached Figure Description

[0024] Figure 1 The image shows the XRD pattern of the FeS2 composite material supported on γ-Al2O3 nanosheets in Example 1.

[0025] Figure 2 This is a SEM image of the FeS2 composite material supported on γ-Al2O3 nanosheets in Example 1.

[0026] Figure 3 This is a TEM image of the FeS2 composite material supported on γ-Al2O3 nanosheets in Example 1.

[0027] Figure 4 The image shows the XRD pattern of the γ-Al2O3 nanosheets in Comparative Example 1.

[0028] Figure 5 A graph showing the relationship between time and degradation rate when THX is degraded under different conditions.

[0029] Figure 6 The graph shows the effect of γ-Al2O3 nanosheet-supported FeS2 composite material on the activation of PMS and degradation of THX under different pH conditions in Example 1. Detailed Implementation

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0031] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0032] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0033] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0034] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0035] To achieve the goal of degrading THX, the present invention provides the following technical solution:

[0036] Preparation of FeS2 composite material supported on γ-Al2O3 nanosheets:

[0037] (1) Aluminum salt, potassium sulfate and urea were mixed in ultrapure water and transferred to a reaction vessel for heating after complete dissolution. After cooling, the precipitate was collected. The precipitate was then calcined in a muffle furnace to obtain γ-Al2O3 nanosheets.

[0038] (2) Add iron salt and sulfur source to N,N-dimethylformamide respectively. After they are completely dissolved, add γ-Al2O3 nanosheets obtained in step (1). After stirring the mixed solution continuously, transfer it to the reaction vessel for solvothermal reaction to obtain the precipitate after the reaction.

[0039] (3) The precipitate in step (2) is filtered, washed, dried, ground and sieved to obtain the γ-Al2O3 nanosheet-supported FeS2 composite material.

[0040] In some optional embodiments of the present invention, in step (1), the aluminum salt is preferably aluminum nitrate nonahydrate, the mass concentration ratio of aluminum nitrate nonahydrate to potassium sulfate is 2.4:1, and the mass ratio of aluminum nitrate nonahydrate to urea is 3:1; exemplaryly, in the following preferred embodiments of the present invention, the amount ratio of aluminum nitrate nonahydrate, potassium sulfate and urea is 1.2g:0.5g:0.4g, and the total volume of the reaction solution is 100mL.

[0041] In some optional embodiments of the present invention, the iron salt in step (2) is preferably ferric nitrate nonahydrate, and the sulfur source is preferably thiourea; the molar concentration ratio of the ferric nitrate nonahydrate and thiourea is 1:2; for example, in the following preferred embodiments of the present invention, the concentration of the ferric nitrate nonahydrate is 1.0 mmol / L, and the concentration of the thiourea is 2.0 mmol / L.

[0042] In some optional embodiments of the present invention, the specific operation steps of the heating reaction in step (2) can be selected as follows: the stirring time of the mixed solution is 2-3 hours, the temperature of the solvothermal reaction of the mixed solution is 160-180°C, and the time is 8-10 hours. For example, in the following preferred embodiments of the present invention, the solvothermal reaction is carried out at 180°C for 8 hours.

[0043] In some optional embodiments of the present invention, the specific operation steps of washing in step (3) can be selected as follows: washing 2 to 5 times with deionized water and anhydrous ethanol respectively; for example, in the following preferred embodiments of the present invention, washing 3 times with deionized water and anhydrous ethanol respectively.

[0044] In some optional embodiments of the present invention, the specific operation steps of drying in step (3) may be selected as: vacuum drying at 60-80°C; for example, in the following preferred embodiments of the present invention, the drying is vacuum drying at 60°C.

[0045] In the following preferred embodiments of the present invention, in step (3), the grinding and sieving is done through a 200-mesh sieve.

[0046] A method for degrading THX in water includes the following steps: adding the γ-Al2O3 nanosheet-supported FeS2 composite material and persulfate to an aqueous solution containing THX to initiate a reaction and achieve THX degradation.

[0047] In the following preferred embodiments of the present invention, the concentration of THX in the aqueous solution is 10 mg / L.

[0048] In the following preferred embodiments of the present invention, the ratio of the aqueous solution, the γ-Al2O3 nanosheet-supported FeS2 composite material, and persulfate is 100 mL: 0.02 g: 0.02 g.

[0049] Unless otherwise specified, "room temperature" in this invention refers to 23-25°C.

[0050] All raw materials used in this invention were purchased from the market.

[0051] Example 1

[0052] Preparation steps of a γ-Al2O3 nanosheet-supported FeS2 composite material:

[0053] 1) Weigh 1.2g aluminum nitrate nonahydrate, 0.56g potassium sulfate and 0.4g urea, add them to 64mL of ultrapure water, stir well to obtain transparent solution A;

[0054] 2) Transfer solution A to a high-pressure reactor and hydrothermally react at 180°C for 6 hours. After the reaction is complete, cool to room temperature and wash three times alternately with ultrapure water and anhydrous methanol to obtain precipitate γ-AlOOH.

[0055] 3) The obtained γ-AlOOH was placed in a muffle furnace and heated to 500℃ at a heating rate of 5℃ / min, and held for 2h to obtain γ-Al2O3 nanosheets;

[0056] 4) Add 5 mmol of ferric nitrate nonahydrate and 10 mmol of thiourea to 30 mL of N,N-dimethylformamide and stir to form solution B;

[0057] 5) Add 0.1g of the γ-Al2O3 nanosheets prepared in step 3) to solution B, continue stirring for 10min, and then stir at a constant speed for 2h to obtain a homogeneous mixture C;

[0058] 6) Transfer the mixture C to a high-pressure reactor and react at 180°C for 8 hours. After the reaction is complete, allow it to cool naturally to room temperature.

[0059] 7) The solid product obtained from the reaction was collected by centrifugation, washed three times alternately with ultrapure water and anhydrous ethanol, dried under vacuum at 70°C, ground and passed through a 200-mesh sieve to obtain the γ-Al2O3-supported FeS2 composite material.

[0060] The γ-Al₂O₃-supported FeS₂ composite material prepared in Example 1 was subjected to X-ray diffraction, scanning electron microscopy, and transmission electron microscopy tests. The test results are as follows: Figure 1-3 As shown.

[0061] Depend on Figure 1 It can be seen that the synthesized material exhibits characteristic diffraction peaks of both γ-Al2O3 (JCPDS card number 04-0880) and FeS2 (JCPDS card number 37-0475). Among them, the diffraction peaks located at 2θ = 37.5°, 45.8° and 66.8° correspond to the (311), (400) and (440) crystal planes of γ-Al2O3, respectively; the diffraction peaks located at 2θ = 32.0°, 37.1°, 40.7°, 50.4° and 55.1° correspond to the (111), (200), (210), (311) and (312) crystal planes of FeS2, respectively.

[0062] Figure 2-3 The test results show that the synthesized material has a relatively uniform morphology, good dispersion, and no obvious agglomeration. These results further confirm that FeS2 is effectively loaded on the γ-Al2O3 support surface while maintaining its nanoscale characteristics.

[0063] Comparative Example 1

[0064] 1) Add 5 mmol of ferric nitrate nonahydrate and 10 mmol of thiourea to 30 mL of N,N-dimethylformamide and stir to form solution D;

[0065] 2) Transfer the mixture D to a high-pressure reactor and react at 180°C for 8 hours. After the reaction is complete, allow it to cool naturally to room temperature.

[0066] 3) The solid product obtained from the reaction was collected by centrifugation, washed three times alternately with ultrapure water and anhydrous ethanol, dried under vacuum at 70°C, ground and passed through a 200-mesh sieve to obtain FeS2.

[0067] X-ray diffraction tests were performed on the FeS2 prepared in Comparative Example 1, and the results are as follows: Figure 4 As shown, this demonstrates the successful synthesis of FeS2 material.

[0068] Comparative Example 2

[0069] 1) Add 5 mmol of ferric nitrate nonahydrate and 10 mmol of thiourea to 30 mL of N,N-dimethylformamide and stir to form solution B;

[0070] 2) Add 0.1g of commercial Al2O3 (average particle size 1.0μm) to solution B, continue stirring for 10min, and then stir at a constant speed for 2h to obtain a homogeneous mixture C;

[0071] 3) Transfer the mixture C to a high-pressure reactor and react at 180°C for 8 hours. After the reaction is complete, allow it to cool naturally to room temperature.

[0072] 4) The solid product obtained from the reaction was collected by centrifugation, washed three times alternately with ultrapure water and anhydrous ethanol, dried under vacuum at 70°C, ground and passed through a 200-mesh sieve to obtain the Al2O3-supported FeS2 composite material.

[0073] Application examples

[0074] A method for activating persulfate to degrade the neonicotinoid pesticide thiamethoxam (THX) in water:

[0075] Experimental group 1:

[0076] 100 mL of 10 mg / L THX solution was added to an Erlenmeyer flask. The mass concentrations of both the γ-Al₂O₃-supported FeS₂ composite material and PMS were set to 0.2 g / L. (In addition, experimental groups were set up with only 0.2 g / L γ-Al₂O₃ nanosheets from Example 1, 0.2 g / L FeS₂ from Comparative Example 1 and 0.2 g / L PMS, 0.2 g / L Al₂O₃-supported FeS₂ composite material from Comparative Example 2 and 0.2 g / L PMS, and 0.2 g / L PMS). At specified time points, 0.5 mL of the filtered reaction solution was sampled and quickly added to a brown vial containing 0.5 mL of methanol to terminate the reaction. The remaining THX concentration was immediately analyzed.

[0077] Test results are as follows Figure 5 As shown, by Figure 5 It can be observed that, compared with FeS2 and commercial Al2O3-supported FeS2 composites, the composite material of FeS2 supported by γ-Al2O3 nanosheets exhibits higher activation performance for PMS. After 60 min of reaction, the THX removal rate exceeds 90%, while the removal rate of THX using only γ-Al2O3 nanosheets or PMS is relatively low.

[0078] Experimental group 2:

[0079] Add 100 mL of 10 mg / L THX solution to an Erlenmeyer flask, and adjust the pH of the solution to 3.07, 5.33, 7.01, 8.97, and 10.57 respectively using 0.1 M H2SO4 or NaOH. Then add 0.2 g / L of γ-Al2O3-supported FeS2 composite material and stir until homogeneous. Add 0.2 g / L PMS to initiate the reaction. At specified time points, take a 0.5 mL sample of the filtered reaction solution, quickly add it to a brown vial containing 0.5 mL of methanol to terminate the reaction, and immediately analyze the remaining THX concentration.

[0080] Test results are as follows Figure 6 As shown, by Figure 6 It can be observed that within the pH range of 3.07-10.57, the γ-Al2O3-supported FeS2 composite material can effectively remove THX from PMS. This is mainly attributed to the surface hydroxyl groups of γ-Al2O3, which create a buffer microenvironment at the catalyst interface, thereby achieving stable activation of PMS.

[0081] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. The application of a γ-alumina nanosheet-supported ferrous disulfide composite material in the degradation of neonicotinoid pesticides by activated PMS, characterized in that, The preparation steps of the γ-alumina nanosheet-supported ferrous disulfide composite material include: adding an iron source, a sulfur source and γ-alumina nanosheets to an organic solvent, mixing them evenly and then carrying out a solvothermal reaction, and the resulting precipitate is the γ-alumina nanosheet-supported ferrous disulfide composite material. The preparation steps of the γ-alumina nanosheets include: mixing aluminum salt, potassium sulfate and urea in water, obtaining γ-AlOOH through hydrothermal reaction, and calcining the γ-AlOOH to obtain the γ-alumina nanosheets.

2. The application according to claim 1, characterized in that, The molar ratio of Fe in the iron source to S in the sulfur source is 1:

2.

3. The application according to claim 1, characterized in that, The concentration of the iron source in the organic solvent is 1 mmol / L; the concentration of the sulfur source in the organic solvent is 2 mmol / L.

4. The application according to claim 1, characterized in that, The solvothermal reaction is carried out at a temperature of 160-180°C for 8-10 hours.

5. The application according to claim 1, characterized in that, The process after the solvothermal reaction also includes separation, drying and grinding steps.

6. The application according to claim 1, characterized in that, The hydrothermal reaction is carried out at a temperature of 160-180℃ for 6-8 hours.

7. The application according to claim 1, characterized in that, The calcination temperature is 450~500℃ and the time is 2h.

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