Gamma-aluminum oxide nanosheet loaded ferrous disulfide composite material as well as preparation method and application thereof

Abstract

The invention discloses a gamma-aluminum oxide nanosheet loaded ferrous disulfide composite material as well as a preparation method and application thereof, and belongs to the technical field of environmental remediation materials. The preparation method of the gamma-aluminum oxide nanosheet loaded ferrous disulfide composite material comprises the following steps: adding an iron source, a sulfur source and gamma-aluminum oxide nanosheets into an organic solvent, uniformly mixing, and carrying out solvothermal reaction to obtain a precipitate, namely the gamma-aluminum oxide nanosheet loaded ferrous disulfide composite material. The gamma-Al2O3 nanosheet used in the invention has a relatively high specific surface area, can provide sufficient loading sites for FeS2, and prevents reduction of catalytic activity caused by agglomeration of single FeS2. The surface of the gamma-Al2O3 nanosheet contains a large number of hydroxyl functional groups, a buffer microenvironment can be created, the pH application range of FeS2 is greatly widened, the composite material shows excellent oxidant activation performance under the condition that the pH is 3-11, and efficient degradation of pollutants is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of environmental remediation materials, and particularly relates to a gamma-alumina nanosheet loaded ferrous disulfide composite material and a preparation method and application thereof. BACKGROUND

[0002] The single persulfate (PMS) based advanced oxidation technology can produce sulfate radicals (SO4 ·- ) with high oxidation potential, and thus has a wide application prospect in the degradation and treatment of organic pollutants in water bodies. When PMS is used to degrade organic pollutants in water bodies, a catalyst is usually added to activate PMS. Therefore, developing a new catalyst that can efficiently activate PMS is a direction worth exploring in the field. SUMMARY

[0003] The application aims to provide a gamma-alumina nanosheet loaded ferrous disulfide composite material and a preparation method and application thereof.

[0004] To achieve the above-mentioned purpose, the application provides the following technical solutions.

[0005] One of the technical solutions of the application is to provide a preparation method of a gamma-alumina nanosheet loaded ferrous disulfide composite material, which comprises the following steps.

[0006] Iron source, sulfur source and gamma-alumina nanosheet are added into an organic solvent, and then mixed uniformly to perform a solvothermal reaction. The obtained precipitate is the gamma-alumina nanosheet loaded ferrous disulfide composite material.

[0007] The application uses FeS2 as a material for activating PMS due to its good electronic structure and Fe(II) / Fe(III) cyclic ability. However, bare FeS2 is prone to particle agglomeration, has poor reaction stability, and is sensitive to pH conditions, which seriously restricts its activation efficiency and environmental adaptability. Therefore, FeS2 is loaded on a gamma-alumina (gamma-Al2O3) carrier with high stability, high specific surface area, good thermal stability and rich surface hydroxyl groups, so as to effectively improve the dispersibility and interfacial reactivity of FeS2. The nanosheet structure of gamma-Al2O3 not only helps to form rich loading sites, but also can regulate the interfacial microenvironment, so as to improve the activation performance and stability of FeS2 and expand its application potential in the PMS activation system.

[0008] Optionally, the organic solvent comprises 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; 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℃, and the time is 8-10h.

[0013] Preferably, after the solvothermal reaction, the steps of separation, drying and grinding are further included.

[0014] Preferably, the preparation step of the γ-alumina nanosheet comprises: mixing an 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 nanosheet.

[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 1.2g / L, the concentration of potassium sulfate in water is 0.5g / L, and the concentration of urea in water is 0.4g / L.

[0016] More preferably, the temperature of the hydrothermal reaction is 160-180℃, and the time is 6-8h.

[0017] More preferably, the temperature of the calcination is 450-500℃, and the time is 2h.

[0018] The second technical scheme of the present application provides a γ-alumina nanosheet loaded ferrous disulfide composite material prepared by the preparation method of the γ-alumina nanosheet loaded ferrous disulfide composite material.

[0019] The third technical scheme of the present application provides an application of the γ-alumina nanosheet loaded ferrous disulfide composite material in activating PMS to degrade neonicotinoid pesticides.

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

[0021] (1) The γ-Al2O3 nanosheet used in the present application has 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 agglomeration.

[0022] (2) The γ-Al2O3 nanosheet used in the present application contains a large number of hydroxyl functional groups on the surface, which can create a buffer microenvironment and greatly improve the pH application range of FeS2, so that the composite material exhibits excellent oxidant activation performance under the condition of pH 3-11, and realizes efficient degradation of pollutants.

[0023] (3) The preparation method provided by the application has mild reaction conditions, does not involve toxic and harmful raw materials, and the prepared catalyst is stable, efficient, environmentally friendly, can effectively reduce the activation energy of persulfate and other oxidants, and realizes efficient removal of thiamethoxam (THX). BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 XRD pattern of the γ-Al2O3 nanosheet loaded FeS2 composite material in Example 1.

[0025] Figure 2 SEM image of the γ-Al2O3 nanosheet loaded FeS2 composite material in Example 1.

[0026] Figure 3 TEM image of the γ-Al2O3 nanosheet loaded FeS2 composite material in Example 1.

[0027] Figure 4 XRD pattern of the γ-Al2O3 nanosheet in Comparative Example 1.

[0028] Figure 5 Time-degradation rate relationship diagram when THX is degraded under different conditions.

[0029] Figure 6 Effect diagram of the γ-Al2O3 nanosheet loaded FeS2 composite material in Example 1 activating PMS to degrade THX under different pH conditions. DETAILED DESCRIPTION

[0030] The various illustrative embodiments of the present application will now be described in detail in connection with the following figures. This description is made for the purpose of illustrating the general principles of the application and is not meant to limit the present application. Rather, the present application should be given its broadest possible interpretation within the scope of the appended claims.

[0031] It should be noted that the present application does not describe in detail the conventional operation means in the art, and is not the focus of the present application.

[0032] In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value within the stated range, and any other stated value or intermediate value within the stated range, is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0033] Unless otherwise indicated, all technical and scientific terms have the same meaning as those one of ordinary skill in the art of the invention would understand. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described.

[0034] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and mean "including but not limited to".

[0035] To achieve the purpose of degrading THX, the present application provides the following technical solutions:

[0036] Preparation of γ-Al2O3 nanosheet loaded FeS2 composite material:

[0037] (1) The aluminum salt, potassium sulfate and urea were mixed in ultrapure water, and after complete dissolution, they were transferred to a reaction kettle for heating. After cooling, the precipitate was collected. The precipitate was again placed in a muffle furnace for calcination treatment to obtain γ-Al2O3 nanosheets.

[0038] (2) Iron salt and sulfur source were added to N,N-dimethylformamide, respectively, and after complete dissolution, the γ-Al2O3 nanosheets obtained in step (1) were added. After continuous stirring of the mixed solution, it was transferred to a reaction kettle for solvothermal reaction to obtain the precipitate after reaction.

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

[0040] In some optional embodiments of the present application, 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; for example, in the following preferred embodiments of the present application, the use 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 application, in step (2), the iron salt is preferably iron nitrate nonahydrate, and the sulfur source is preferably thiourea; the molar concentration ratio of iron nitrate nonahydrate to thiourea is 1:2; for example, in the following preferred embodiments of the present application, the concentration of iron nitrate nonahydrate is 1.0mmol / L, and the concentration of thiourea is 2.0mmol / L.

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

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

[0044] In some optional embodiments of the present application, in step (3), the specific operation steps of the drying can be selected as follows: vacuum drying at 60-80℃; for example, in the following preferred embodiments of the present application, the drying is carried out at 60℃ under vacuum.

[0045] In the following preferred embodiments of the present application, in step (3), the grinding and sieving are carried out through a 200-mesh sieve.

[0046] The method for degrading THX in water comprises the following steps: adding the γ-Al2O3 nanosheet loaded FeS2 composite material and persulfate into a THX-containing aqueous solution to start the reaction, so as to achieve the degradation of THX.

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

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

[0049] In the present application, “room temperature” refers to 23-25℃, unless otherwise specified.

[0050] In the present application, all raw materials are commercially available.

[0051] Example 1

[0052] A preparation step of a γ-Al2O3 nanosheet loaded FeS2 composite material:

[0053] 1) 1.2g of aluminum nitrate nonahydrate, 0.56g of potassium sulfate and 0.4g of urea are weighed and added into 64mL of ultrapure water, and stirred uniformly to obtain a transparent solution A;

[0054] 2) Solution A was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 180°C for 6 h. After the reaction, the solution was cooled to room temperature and washed alternately with ultrapure water and anhydrous methanol three times to obtain a precipitated γ-AlOOH.

[0055] 3) placing the obtained γ-AlOOH in a muffle furnace, heating it to 500°C at a heating rate of 5°C / min, and keeping it at that temperature for 2 hours 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 0.1 g of the γ-Al2O3 nanosheets prepared in step 3) to solution B, continue stirring for 10 minutes, and then react at a constant stirring speed for 2 hours to obtain a uniform mixed solution C;

[0058] 6) Transfer the mixed solution C to a high-pressure reactor and react at 180°C for 8 hours. After the reaction is completed, naturally cool to room temperature;

[0059] 7) The solid product obtained by the reaction was collected by centrifugation, washed alternately with ultrapure water and anhydrous ethanol three times, and vacuum dried at 70° C. After grinding, it was passed through a 200-mesh sieve to obtain a γ-Al 2 O 3 loaded FeS 2 composite material.

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

[0061] Depend on Figure 1 It can be seen that the synthesized material exhibits characteristic diffraction peaks of both γ-Al2O3 (JCPDS Card No. 04-0880) and FeS2 (JCPDS Card No. 37-0475). The diffraction peaks at 2θ = 37.5°, 45.8°, and 66.8° correspond to the (311), (400), and (440) crystal planes of γ-Al2O3, respectively; and the diffraction peaks 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] Figures 2-3 The test results show that the morphology of the synthesized material is relatively uniform and well dispersed, with no obvious agglomeration. This result further confirms that FeS2 is effectively loaded on the surface of the γ-Al2O3 carrier and maintains 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 mixed solution D to a high-pressure reactor and react at 180°C for 8 hours. After the reaction is completed, naturally cool to room temperature;

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

[0067] The FeS2 prepared in Comparative Example 1 was subjected to X-ray diffraction test, and the results were as follows: Figure 4 As shown, it indicates 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 0.1 g of commercial Al2O3 (average particle size 1.0 μm) to solution B, continue stirring for 10 minutes, and then react at a constant stirring speed for 2 hours to obtain a homogeneous mixed solution C;

[0071] 3) Transfer the mixed solution C to a high-pressure reactor and react at 180°C for 8 hours. After the reaction is completed, naturally cool to room temperature;

[0072] 4) The solid product obtained by the reaction was collected by centrifugation, washed alternately with ultrapure water and anhydrous ethanol three times, and vacuum dried at 70° C. After grinding, it was passed through a 200-mesh sieve to obtain an Al 2 O 3 loaded FeS 2 composite material.

[0073] Application Examples

[0074] Method for activating peroxymonosulfate to degrade the neonicotinoid pesticide thiamethoxam (THX) in water:

[0075] Experimental Group 1:

[0076] A 100 mL THX solution with a concentration of 10 mg / L was added to a conical flask, and the mass concentration of the γ-Al2O3 loaded FeS2 composite and PMS was set to 0.2 g / L (in addition, a test group in which only 0.2 g / L of the γ-Al2O3 nanosheet of Example 1 was added, a test group in which 0.2 g / L of FeS2 and 0.2 g / L of PMS of Comparative Example 1 were added, a test group in which 0.2 g / L of the Al2O3 loaded FeS2 composite of Comparative Example 2 and 0.2 g / L of PMS were added, and a test group in which 0.2 g / L of PMS was added) was set. 0.5 mL of filtered reaction solution was sampled at the specified time point, quickly added to a brown vial containing 0.5 mL of methanol to terminate the reaction, and immediately analyzed for the residual concentration of THX.

[0077] The test results are shown in Table 1, and it can be found that, compared with FeS2 and the commercial Al2O3 loaded FeS2 composite, the γ-Al2O3 nanosheet loaded FeS2 composite has higher activation performance for PMS, and the removal rate of THX is more than 90% after 60 min of reaction, and the removal rate of THX using only the γ-Al2O3 nanosheet or PMS is low. Figure 5 Figure 5 It can be found that, within the pH range of 3.07-10.57, the γ-Al2O3 loaded FeS2 composite can effectively remove THX by activating PMS, which is mainly due to the surface hydroxyl group of γ-Al2O3, which builds a buffer microenvironment at the catalyst interface and realizes stable activation of PMS.

[0078] Test group 2:

[0079] A 100 mL THX solution with a concentration of 10 mg / L was added to a conical flask, and the mass concentration of the γ-Al2O3 loaded FeS2 composite and PMS was set to 0.2 g / L (in addition, a test group in which only 0.2 g / L of the γ-Al2O3 nanosheet of Example 1 was added, a test group in which 0.2 g / L of FeS2 and 0.2 g / L of PMS of Comparative Example 1 were added, a test group in which 0.2 g / L of the Al2O3 loaded FeS2 composite of Comparative Example 2 and 0.2 g / L of PMS were added, and a test group in which 0.2 g / L of PMS was added) was set. 0.5 mL of filtered reaction solution was sampled at the specified time point, quickly added to a brown vial containing 0.5 mL of methanol to terminate the reaction, and immediately analyzed for the residual concentration of THX.

[0080] The test results are shown in Table 1, and it can be found that, compared with FeS2 and the commercial Al2O3 loaded FeS2 composite, the γ-Al2O3 nanosheet loaded FeS2 composite has higher activation performance for PMS, and the removal rate of THX is more than 90% after 60 min of reaction, and the removal rate of THX using only the γ-Al2O3 nanosheet or PMS is low. Figure 6 Figure 6 It can be found that, within the pH range of 3.07-10.57, the γ-Al2O3 loaded FeS2 composite can effectively remove THX by activating PMS, which is mainly due to the surface hydroxyl group of γ-Al2O3, which builds a buffer microenvironment at the catalyst interface and realizes stable activation of PMS.

[0081] The above-described examples only describe the preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those of ordinary skill in the art should fall within the protection scope defined by the claims of the present application.​​

Claims

1. A method for preparing a γ-alumina nanosheet-loaded ferrous disulfide composite material, characterized in that: The following steps are involved: An iron source, a sulfur source and gamma-alumina nanosheets are added to an organic solvent, mixed evenly and then subjected to a solvent thermal reaction, and the obtained precipitate is the gamma-alumina nanosheet-loaded ferrous disulfide composite material.

2. The method for preparing the γ-alumina nanosheet-loaded ferrous disulfide composite material according to claim 1, wherein: The molar ratio of Fe in the iron source to S in the sulfur source is 1:

2.

3. The method for preparing the γ-alumina nanosheet-loaded ferrous disulfide composite material 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 method for preparing the γ-alumina nanosheet-loaded ferrous disulfide composite material according to claim 1, characterized in that: The temperature of the solvent thermal reaction is 160-180° C., and the time is 8-10 hours.

5. The method for preparing the γ-alumina nanosheet-loaded ferrous disulfide composite material according to claim 1, characterized in that: The solvothermal reaction also includes separation, drying and grinding steps.

6. The method for preparing the γ-alumina nanosheet-loaded ferrous disulfide composite material according to claim 1, characterized in that: 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.

7. The method for preparing the γ-alumina nanosheet-loaded ferrous disulfide composite material according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 160-180° C., and the time is 6-8 hours.

8. The method for preparing the γ-alumina nanosheet-loaded ferrous disulfide composite material according to claim 1, characterized in that: The calcination temperature is 450-500° C. and the calcination time is 2 hours.

9. A γ-alumina nanosheet-supported ferrous disulfide composite material prepared according to the method for preparing a γ-alumina nanosheet-supported ferrous disulfide composite material according to any one of claims 1 to 8.

10. Use of the γ-alumina nanosheet-loaded ferrous disulfide composite material according to claim 9 in activating PMS to degrade neonicotinoid pesticides.

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