Magnetite composite material as well as preparation method and application thereof

Abstract

The invention relates to a magnetite composite material and a preparation method and application thereof, and relates to the technical field of magnetite materials, the preparation method comprises the following steps: stirring and mixing magnetite, zeolite powder and a binder, and then carrying out alternate microwave plasma treatment at first microwave power and second microwave power to obtain a first mixture; performing freezing and thawing cycle treatment on the first mixture to obtain a second mixture; and granulating the second mixture, and calcining in an inert atmosphere to obtain the magnetite composite material, wherein the first microwave power ranges from 700 W to 860 W, and the second microwave power ranges from 260 W to 380 W. The magnetite composite material is prepared by taking the magnetite and the zeolite powder as raw materials through a microwave plasma-freeze thawing-calcination combined treatment process, so that the sewage treatment performance of the magnetite material is effectively improved, the treatment requirement of high-concentration aniline wastewater can be met, and the defects in the prior art are overcome.

Description

Technical Field

[0001] The invention relates to the technical field of magnetite materials, and in particular to a magnetite composite material and a preparation method and application thereof. Background Art

[0002] With the rapid development of industrialization, the treatment of high-concentration organic wastewater has become a major challenge in the field of environmental protection, especially wastewater containing aniline and other difficult-to-degrade organic matter. As an important chemical raw material, aniline is widely used in dyes, pesticides, medicines, rubber and other industries. However, the large amount of wastewater generated during its production and use poses a severe test to traditional water treatment technology due to its high aniline content, high toxicity and poor biodegradability.

[0003] At present, the treatment technologies for high-concentration aniline wastewater mainly include physical methods (such as adsorption, extraction), chemical methods (such as Fenton oxidation method, etc.) and biological methods (such as aerobic / anaerobic biological treatment). However, these methods have limitations in practical applications. Physical methods often have high treatment costs, and the regeneration and disposal of adsorbents or extractants are prominent; although chemical methods can effectively degrade aniline, they may cause secondary pollution and have high requirements for equipment materials; biological methods inhibit microbial activity due to the toxicity of aniline, and the treatment efficiency is low, making it difficult to meet emission standards. In particular, existing materials for treating high-concentration aniline wastewater, such as activated carbon, resin, bentonite, etc., have certain adsorption or catalytic degradation capabilities, but are easily saturated and ineffective under long-term operation, and are difficult to regenerate, and the treatment effect is unstable. In addition, these materials have limited adaptability to high-concentration aniline wastewater, and it is difficult to meet increasingly stringent environmental protection requirements and efficient treatment needs.

[0004] Therefore, it is urgent to develop a new, efficient, stable and economically feasible material for aniline wastewater treatment. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a magnetite composite material and a preparation method and application thereof.

[0006] In a first aspect, the present invention provides a method for preparing a magnetite composite material, the preparation method comprising the following steps:

[0007] The magnetite, zeolite powder and the binder are stirred and mixed, and then subjected to alternating microwave plasma treatment with a first microwave power and a second microwave power to obtain a first mixed material;

[0008] Subjecting the first mixed material to a freeze-thaw cycle to obtain a second mixed material;

[0009] Granulating the second mixed material, and then calcining it under an inert atmosphere to obtain the magnetite composite material;

[0010] Wherein, the first microwave power is 700-860W and the second microwave power is 260-380W.

[0011] Furthermore, the weight ratio of the magnetite, the zeolite powder and the binder is (1-1.5):(3-5):(1.5-2).

[0012] Furthermore, the binder comprises a polyvinyl alcohol aqueous solution with a concentration of 0.02 to 0.04 g / mL, the particle size of the zeolite powder is 50 to 150 meshes, and the magnetite comprises vanadium-titanium magnetite.

[0013] Furthermore, the working condition parameters of the alternating microwave plasma treatment include: the first microwave power is 750W, the second microwave power is 315W, the number of alternating microwave plasma treatments is 5 to 8 times, the time of each microwave plasma treatment is 15 to 45 seconds, and the working medium is argon.

[0014] Furthermore, the working condition parameters of the freeze-thaw cycle treatment include: freezing temperature of -30 to -20°C, freezing time of 1 to 2 hours, thawing temperature of 40 to 50°C, thawing time of 2 to 3 hours, and the number of freeze-thaw cycle treatments is 3 to 5 times.

[0015] Furthermore, the working condition parameters of the granulation include: using a disc granulator, and the granulation size is 2 to 5 mm.

[0016] Furthermore, the calcination working condition parameters include: temperature of 400-500° C. and time of 1-2 hours.

[0017] In a second aspect, the present invention provides a magnetite composite material, wherein the magnetite composite material is prepared by the preparation method of the magnetite composite material described in any one of the first aspects.

[0018] In a third aspect, the present invention provides use of the magnetite composite material described in any one of the second aspects in treating wastewater.

[0019] Furthermore, the wastewater is organic wastewater containing aniline, and the concentration of the aniline is ≥100 g / L.

[0020] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0021] An embodiment of the present invention provides a method for preparing a magnetite composite material. The present invention uses magnetite and zeolite powder as raw materials and prepares a magnetite composite material through a microwave plasma-freeze-thaw-calcination combined treatment process, which effectively improves the sewage treatment performance of the magnetite material, can meet the treatment requirements of high-concentration aniline wastewater, and makes up for the shortcomings of the prior art.

[0022] Specifically:

[0023] 1. Raw material selection and basic mixing:

[0024] Magnetite: As the main material, magnetite has good magnetic properties, which facilitates subsequent separation and recovery. At the same time, its surface properties can be regulated through treatment to enhance its adsorption capacity for pollutants.

[0025] Zeolite powder: Zeolite is a porous material with rich microporous structure, which can provide a large number of adsorption sites and has good adsorption performance for organic matter and heavy metal ions. Combining it with magnetite can be expected to obtain stronger adsorption capacity and a wider adsorption range.

[0026] Binder: used to enhance the bonding force between magnetite and zeolite powder and ensure the structural stability of the composite material.

[0027] 2. Microwave plasma treatment:

[0028] Alternating microwave power: Using alternating microwave powers of 700-860W and 260-380W can generate microwave fields of different intensities. This alternating effect helps to form a more uniform heat distribution inside the material, promote interaction between raw materials, and avoid structural damage caused by local overheating.

[0029] Plasma effect: Plasma under microwave excitation can produce a high-temperature, high-energy environment, which helps to change the surface structure and chemical properties of materials, increase active sites, and improve the adsorption and catalytic properties of materials.

[0030] 3. Freeze-thaw cycle treatment:

[0031] The freeze-thaw process generates physical stress inside the material through the formation and melting of ice crystals, which helps to further open the pore structure of the material, increase the specific surface area, and thus enhance the adsorption capacity. At the same time, the freeze-thaw cycle may also promote the formation of tiny cracks inside the material, providing more channels for the diffusion and adsorption of pollutants.

[0032] 4. Calcination under inert atmosphere:

[0033] High-temperature calcination under the protection of inert gas (such as nitrogen, argon) can stabilize the structure of the material and avoid performance degradation caused by oxidation reaction. At the same time, high-temperature treatment can further activate the surface of the material and improve its catalytic activity and stability.

[0034] 5. Mutual synergy mechanism

[0035] 5.1. Synergy of structure and performance: The magnetic properties of magnetite combined with the porosity of zeolite powder form a composite material with both magnetic separation properties and high adsorption capacity. Microwave plasma treatment enhances this synergy by changing the surface structure and chemical properties of the material.

[0036] 5.2. Synergy of physical and chemical treatment: The physical effect of freeze-thaw cycle and the chemical effect of microwave plasma and calcination complement each other and jointly promote the improvement of material performance. Physical treatment opens the pore structure, while chemical treatment activates the surface sites. The synergistic effect of the two improves the material's ability to adsorb and degrade organic pollutants such as aniline.

[0037] 5.3. Cumulative effect of multi-step treatment: From raw material mixing to final calcination, each step of treatment has a positive impact on the performance of the material. The cumulative effect of these steps makes the final magnetite composite material show excellent performance in treating high-concentration aniline wastewater.

[0038] In summary, the present invention successfully prepared a magnetite composite material with high sewage treatment performance through carefully designed preparation steps and synergistic mechanism, which is particularly suitable for treating high-concentration aniline wastewater, and provides strong technical support for environmental protection and water resource reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0041] Figure 1 A schematic flow chart of a method for preparing a magnetite composite material provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0044] In a first aspect, the present invention provides a method for preparing a magnetite composite material, such as Figure 1 As shown, the preparation method comprises the following steps:

[0045] The magnetite, zeolite powder and the binder are stirred and mixed, and then subjected to alternating microwave plasma treatment with a first microwave power and a second microwave power to obtain a first mixed material;

[0046] Subjecting the first mixed material to a freeze-thaw cycle to obtain a second mixed material;

[0047] Granulating the second mixed material, and then calcining it under an inert atmosphere to obtain the magnetite composite material;

[0048] Wherein, the first microwave power is 700-860W and the second microwave power is 260-380W.

[0049] An embodiment of the present invention provides a method for preparing a magnetite composite material. The present invention uses magnetite and zeolite powder as raw materials and prepares a magnetite composite material through a microwave plasma-freeze-thaw-calcination combined treatment process, which effectively improves the sewage treatment performance of the magnetite material, can meet the treatment requirements of high-concentration aniline wastewater, and makes up for the shortcomings of the prior art.

[0050] In some specific embodiments, the weight ratio of the magnetite, the zeolite powder and the binder is (1-1.5):(3-5):(1.5-2).

[0051] In some specific embodiments, the binder includes a polyvinyl alcohol aqueous solution with a concentration of 0.02 to 0.04 g / mL, the particle size of the zeolite powder is 50 to 150 meshes, and the magnetite includes vanadium-titanium magnetite.

[0052] In some specific embodiments, the working condition parameters of the alternating microwave plasma treatment include: the first microwave power is 750W, the second microwave power is 315W, the number of alternating microwave plasma treatments is 5 to 8 times, the time of each microwave plasma treatment is 15 to 45 seconds, and the working medium is argon.

[0053] In some specific embodiments, the working condition parameters of the freeze-thaw cycle treatment include: freezing temperature of -30 to -20°C, freezing time of 1 to 2 hours, thawing temperature of 40 to 50°C, thawing time of 2 to 3 hours, and the number of freeze-thaw cycle treatments is 3 to 5 times.

[0054] In some specific embodiments, the working condition parameters of the granulation include: using a disc granulator, and the granulation size is 2 to 5 mm.

[0055] In some specific embodiments, the calcination working condition parameters include: temperature of 400-500° C. and time of 1-2 hours.

[0056] In a second aspect, the present invention provides a magnetite composite material, wherein the magnetite composite material is prepared by the preparation method of the magnetite composite material described in any one of the first aspects.

[0057] In a third aspect, the present invention provides use of the magnetite composite material described in any one of the second aspects in treating wastewater.

[0058] In some specific embodiments, the wastewater is organic wastewater containing aniline, and the concentration of the aniline is ≥100 g / L.

[0059] It should be noted that the raw material components involved in the magnetite composite material and its preparation method and application provided in the embodiments of the present invention, unless otherwise specified or described, can be directly purchased from the market or made in-house according to existing preparation methods; at the same time, the operating steps involved in the preparation method, unless otherwise specified or described, can be carried out according to existing magnetite composite material preparation methods or using existing equipment, and the present invention document will not repeat them any more.

[0060] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0061] Example 1

[0062] This example provides a magnetite composite material, and the preparation method of the magnetite composite material comprises the following steps:

[0063] Step (1): stirring and mixing vanadium-titanium magnetite, zeolite powder with a particle size of 100 mesh and polyvinyl alcohol aqueous solution with a concentration of 0.03 g / mL in a weight ratio of 1.2:4:1.7, and then performing alternating microwave plasma treatment with a first microwave power and a second microwave power to obtain a first mixed material; wherein the working condition parameters of the alternating microwave plasma treatment include: the first microwave power is 750 W, the second microwave power is 315 W, the total number of alternating microwave plasma treatments is 6 times, the number of microwave plasma treatments with the first microwave power and the number of microwave plasma treatments with the second microwave power are 3 times respectively, the time of each microwave plasma treatment is 25 seconds, and the working medium is argon;

[0064] Step (2): subjecting the first mixed material obtained in step (1) to a freeze-thaw cycle treatment, wherein the freezing temperature is -25°C, the freezing time is 1.5 hours, the thawing temperature is 45°C, the thawing time is 2.5 hours, and the number of freeze-thaw cycle treatments is 4 times, thereby obtaining a second mixed material;

[0065] Step (3): The second mixed material obtained in step (2) is granulated by a disc granulator to obtain particles with a particle size of 2 to 5 mm; the particles are then calcined in an inert atmosphere at a temperature of 460° C. for 1.5 hours, and cooled in the furnace to obtain the magnetite composite material.

[0066] Example 2

[0067] This example provides a magnetite composite material, and the preparation method of the magnetite composite material comprises the following steps:

[0068] Step (1): stirring and mixing vanadium-titanium magnetite, zeolite powder with a particle size of 100 mesh and a polyvinyl alcohol aqueous solution with a concentration of 0.03 g / mL in a weight ratio of 1:3:1.5, and then performing alternating microwave plasma treatment with a first microwave power and a second microwave power to obtain a first mixed material; wherein the working condition parameters of the alternating microwave plasma treatment include: the first microwave power is 700 W, the second microwave power is 380 W, the total number of alternating microwave plasma treatments is 6 times, the number of microwave plasma treatments with the first microwave power and the number of microwave plasma treatments with the second microwave power are 3 times respectively, the time of each microwave plasma treatment is 25 seconds, and the working medium is argon;

[0069] Step (2): subjecting the first mixed material obtained in step (1) to a freeze-thaw cycle treatment, wherein the freezing temperature is -30°C, the freezing time is 1 hour, the thawing temperature is 50°C, the thawing time is 2 hours, and the number of freeze-thaw cycle treatments is 3 times, to obtain a second mixed material;

[0070] Step (3): The second mixed material obtained in step (2) is granulated by a disc granulator to obtain particles with a particle size of 2 to 5 mm; the particles are then calcined in an inert atmosphere at a temperature of 400° C. for 2 hours, and cooled in the furnace to obtain the magnetite composite material.

[0071] Example 3

[0072] This example provides a magnetite composite material, and the preparation method of the magnetite composite material comprises the following steps:

[0073] Step (1): stirring and mixing vanadium-titanium magnetite, zeolite powder with a particle size of 100 mesh and a polyvinyl alcohol aqueous solution with a concentration of 0.03 g / mL in a weight ratio of 1.5:5:2, and then performing alternating microwave plasma treatment with a first microwave power and a second microwave power to obtain a first mixed material; wherein the working condition parameters of the alternating microwave plasma treatment include: the first microwave power is 860 W, the second microwave power is 260 W, the total number of alternating microwave plasma treatments is 6 times, the number of microwave plasma treatments with the first microwave power and the number of microwave plasma treatments with the second microwave power are 3 times respectively, the time of each microwave plasma treatment is 25 seconds, and the working medium is argon;

[0074] Step (2): subjecting the first mixed material obtained in step (1) to a freeze-thaw cycle treatment, wherein the freezing temperature is -20°C, the freezing time is 2 hours, the thawing temperature is 40°C, the thawing time is 3 hours, and the number of freeze-thaw cycle treatments is 3 times, to obtain a second mixed material;

[0075] Step (3): The second mixed material obtained in step (2) is granulated by a disc granulator to obtain particles with a particle size of 2 to 5 mm; the particles are then calcined in an inert atmosphere at a temperature of 500° C. for 1 hour, and cooled in the furnace to obtain the magnetite composite material.

[0076] Comparative Example 1

[0077] This example provides a magnetite composite material and a preparation method thereof, which differs from Example 1 only in that the alternating microwave plasma treatment with the first microwave power and the second microwave power is adjusted to the microwave plasma treatment with the first microwave power; the remaining steps and parameters are the same.

[0078] This example provides a magnetite composite material, and the preparation method of the magnetite composite material comprises the following steps:

[0079] Step (1): stirring and mixing vanadium-titanium magnetite, zeolite powder with a particle size of 100 mesh and a polyvinyl alcohol aqueous solution with a concentration of 0.03 g / mL in a weight ratio of 1.2:4:1.7, and then subjecting the mixture to microwave plasma treatment with a first microwave power to obtain a first mixed material; wherein the working condition parameters of the microwave plasma treatment include: the first microwave power is 750 W, the total number of microwave plasma treatments is 6 times, the time of each microwave plasma treatment is 25 seconds, and the working medium is argon;

[0080] Step (2): subjecting the first mixed material obtained in step (1) to a freeze-thaw cycle treatment, wherein the freezing temperature is -25°C, the freezing time is 1.5 hours, the thawing temperature is 45°C, the thawing time is 2.5 hours, and the number of freeze-thaw cycle treatments is 4 times, thereby obtaining a second mixed material;

[0081] Step (3): The second mixed material obtained in step (2) is granulated by a disc granulator to obtain particles with a particle size of 2 to 5 mm; the particles are then calcined in an inert atmosphere at a temperature of 460° C. for 1.5 hours, and cooled in the furnace to obtain the magnetite composite material.

[0082] Comparative Example 2

[0083] This example provides a magnetite composite material and a preparation method thereof, which is different from Example 1 only in that no freeze-thaw cycle treatment is performed; the remaining steps and parameters are the same.

[0084] This example provides a magnetite composite material, and the preparation method of the magnetite composite material comprises the following steps:

[0085] Step (1): stirring and mixing vanadium-titanium magnetite, zeolite powder with a particle size of 100 mesh and polyvinyl alcohol aqueous solution with a concentration of 0.03 g / mL in a weight ratio of 1.2:4:1.7, and then performing alternating microwave plasma treatment with a first microwave power and a second microwave power to obtain a first mixed material; wherein the working condition parameters of the alternating microwave plasma treatment include: the first microwave power is 750 W, the second microwave power is 315 W, the total number of alternating microwave plasma treatments is 6 times, the number of microwave plasma treatments with the first microwave power and the number of microwave plasma treatments with the second microwave power are 3 times respectively, the time of each microwave plasma treatment is 25 seconds, and the working medium is argon;

[0086] Step (2): The first mixed material obtained in step (1) is granulated by a disc granulator to obtain particles with a particle size of 2 to 5 mm; the particles are then calcined in an inert atmosphere at a temperature of 460° C. for 1.5 hours, and cooled in the furnace to obtain the magnetite composite material.

[0087] Test Case

[0088] In this example, according to the test method disclosed in the prior art (Fenton oxidation method), the magnetite composite material obtained in the above embodiment and comparative example was applied to aniline wastewater treatment. 50g of magnetite composite material sample was loaded into a fixed bed to remove aniline-containing organic wastewater with a concentration of 100g / L. With the assistance of 10mM persulfate, the residence time was 10min. The aniline removal rate (%) was detected and calculated. The test results are shown in Table 1.

[0089] Table 1

[0090] Test samples Aniline removal rate (%) Example 1 98.7 Example 2 93.4 Example 3 95.9 Comparative Example 1 71.3 Comparative Example 2 59.8

[0091] It can be seen from Table 1 that, compared with Comparative Examples 1 to 2, the magnetite composite material provided in the embodiment of the present invention has a higher removal rate for high concentration 100 g / L aniline-containing organic wastewater. The aniline removal rate of the magnetite composite material provided in Example 1 can reach 98.7%, and the removal efficiency is high.

[0092] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0093] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a magnetite composite material, characterized in that: The preparation method comprises the following steps: The magnetite, zeolite powder and the binder are stirred and mixed, and then subjected to alternating microwave plasma treatment with a first microwave power and a second microwave power to obtain a first mixed material; Subjecting the first mixed material to a freeze-thaw cycle to obtain a second mixed material; Granulating the second mixed material, and then calcining it under an inert atmosphere to obtain the magnetite composite material; Wherein, the first microwave power is 700-860W and the second microwave power is 260-380W.

2. The method for preparing the magnetite composite material according to claim 1, characterized in that: The weight ratio of the magnetite, the zeolite powder and the binder is (1-1.5):(3-5):(1.5-2).

3. The method for preparing the magnetite composite material according to claim 1, characterized in that: The binder comprises a polyvinyl alcohol aqueous solution with a concentration of 0.02 to 0.04 g / mL, the particle size of the zeolite powder is 50 to 150 meshes, and the magnetite comprises vanadium-titanium magnetite.

4. The method for preparing the magnetite composite material according to claim 1, characterized in that: The working condition parameters of the alternating microwave plasma treatment include: the first microwave power is 750W, the second microwave power is 315W, the number of alternating microwave plasma treatments is 5 to 8 times, the time of each microwave plasma treatment is 15 to 45 seconds, and the working medium is argon.

5. The method for preparing the magnetite composite material according to claim 1, characterized in that: The working condition parameters of the freeze-thaw cycle treatment include: a freezing temperature of -30 to -20°C, a freezing time of 1 to 2 hours, a thawing temperature of 40 to 50°C, a thawing time of 2 to 3 hours, and the number of freeze-thaw cycle treatments is 3 to 5 times.

6. The method for preparing the magnetite composite material according to claim 1, characterized in that: The working condition parameters of the granulation include: using a disc granulator, and the granulation size is 2 to 5 mm.

7. The method for preparing a magnetite composite material according to claim 1, characterized in that: The working condition parameters of the calcination include: a temperature of 400 to 500° C. and a time of 1 to 2 hours.

8. A magnetite composite material, characterized in that: The magnetite composite material is prepared by the preparation method of the magnetite composite material according to any one of claims 1 to 7.

9. Use of the magnetite composite material according to claim 8 in treating wastewater.

10. The use according to claim 9, characterized in that: The wastewater is organic wastewater containing aniline, and the concentration of the aniline is ≥100g / L.

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