Magnetic carbon-based attapulgite composite material as well as preparation method and application thereof
Magnetic carbon-based concave-convex rod composite material is prepared through acid etching treatment and biochar modification technology, which solves the problem of difficulty in agglomeration and recycling of concave-convex rod stone nanorod crystals, and achieves efficient adsorption and good recovery.
Patent Information
- Application Number
- CN202510304036.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-06-03
AI Technical Summary
In the prior art, nanorod crystals are prone to agglomeration after dissociation treatment of concave and convex rock stones, resulting in a decrease in specific surface area, affecting its adsorption ability to pollutants. At the same time, it is difficult to recover powders of traditional concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and concave and con
By mixing the concave and concave rock powder with acid solution and acid solution for acid etching, a nanorod crystal suspension of concave and concave rock soil containing iron ions was obtained, and mixed with biochar to dry it to form a precursor powder, and then pyrolytic treatment was performed in an inert atmosphere to prepare a magnetic carbon-based concave and concave rod composite material.
The method is simple to operate and easy to control the conditions. The prepared magnetic carbon-based concave and convex rod composite material has good adsorption and recovery properties, which can effectively prevent nanorod crystal agglomeration and maintain a good adsorption effect.
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Figure CN120079349A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of composite materials, and particularly to a magnetic carbon-based attapulgite composite material, a preparation method thereof, and an application thereof. Background Art
[0002] Attapulgite is a non-metallic mineral with a unique layered structure and a high specific surface area, having good adsorption properties and being widely used in fields such as water treatment and environmental remediation. When attapulgite is used for water treatment, dissociation treatment needs to be carried out first. After the dissociation treatment of attapulgite, its crystal structure is destroyed, resulting in an increase in specific surface area, an increase in adsorption sites and active centers, and thus an improvement in the adsorption capacity for pollutants; the dissociated attapulgite has better dispersibility and can be more evenly distributed in the solution, improving the adsorption efficiency; the dissociation process can also remove impurities in the attapulgite, further purifying the material and enhancing its adsorption effect. Although the dissociation treatment of attapulgite can improve its application effect, after the dissociation treatment of attapulgite, the attapulgite nanorod crystals are prone to agglomeration, causing the dissociated attapulgite nanorods to re-aggregate, resulting in a decrease in specific surface area, thereby affecting its adsorption capacity for pollutants.
[0003] In addition, traditional attapulgite materials exist in the form of powders. After the attapulgite powder treats pollutants in water, the problems of recovery and reuse have not been effectively solved. At present, relevant research has introduced magnetic particles into attapulgite and utilized the magnetism of the magnetic particles to realize the recovery of attapulgite powder. For example, an attapulgite / CoFe 2 O 4 magnetic composite material is prepared by a low-temperature reflux method, and the magnetic particles are loaded on the surface of attapulgite by physical deposition. This physical deposition method may cause the magnetic particles to fall off during the use of the composite material, resulting in that some attapulgite powders still cannot be recovered by magnetic adsorption. In order to improve the binding ability of magnetic particles in attapulgite powder, relevant research has enhanced the binding force between magnetic particles and attapulgite through methods such as chemical modification, but the conditions for constructing stable chemical bonding are relatively harsh and the operation is complex.
[0004] Therefore, there is an urgent need to provide a preparation method for a magnetic attapulgite composite material with simple operation, easy control of conditions, good recyclability, and good adsorption performance for pollutants. Summary of the Invention
[0005] The purpose of the present invention is to provide a magnetic carbon-based attapulgite composite material, a preparation method thereof, and an application thereof. The preparation method provided by the present invention is simple to operate, easy to control conditions, the obtained magnetic carbon-based attapulgite composite material has good adsorption for pollutants in water, and at the same time has good recyclability.
[0006] To achieve the above-mentioned invention objectives, the present invention provides the following technical solutions: The present invention provides a preparation method of a magnetic carbon-based attapulgite composite material, comprising the following steps: (1) Mix attapulgite powder with an acid solution and perform acid etching treatment to obtain an attapulgite nanorod crystal suspension containing iron ions; (2) Mix and dry the attapulgite nanorod crystal suspension containing iron ions obtained in step (1) with biochar in sequence to obtain a precursor powder; (3) Perform pyrolysis treatment on the precursor powder obtained in step (2) in an inert atmosphere to obtain a magnetic carbon-based attapulgite composite material.
[0007] Preferably, the mass content of iron in the attapulgite powder in step (1) is 5-10%.
[0008] Preferably, the acid solution in step (1) includes one or more of hydrochloric acid, sulfuric acid, oxalic acid, and citric acid.
[0009] Preferably, the mass concentration of the acid solution in step (1) is 1-5%.
[0010] Preferably, the temperature of the acid etching treatment in step (1) is 25-150°C; the time of the acid etching treatment is 2-24 h.
[0011] Preferably, the particle size of the biochar in step (2) is ≤50 mm, and the specific surface area of the biochar is ≥20 m 2 / g.
[0012] Preferably, the mass ratio of the attapulgite powder in step (1) to the biochar in step (2) is 1:(0.2-3).
[0013] Preferably, the temperature of the pyrolysis treatment in step (3) is 400-700°C; the time of the pyrolysis treatment is 1-5 h.
[0014] The present invention also provides a magnetic carbon-based attapulgite composite material prepared by the above-mentioned preparation method.
[0015] The present invention also provides the application of the above-mentioned magnetic carbon-based attapulgite composite material in treating organic wastewater.
[0016] The present invention provides a method for preparing a magnetic carbon-based attapulgite composite material, comprising the following steps: mixing attapulgite powder with an acid solution, performing acid etching treatment to obtain an attapulgite nanorod crystal suspension containing iron ions; mixing the attapulgite nanorod crystal suspension containing iron ions with biochar in sequence and drying to obtain a precursor powder; pyrolyzing the precursor powder in an inert atmosphere to obtain the magnetic carbon-based attapulgite composite material. In the present invention, acid etching treatment is first performed on the attapulgite powder, which can dissociate the attapulgite powder into attapulgite nanorod crystals and dissolve the iron compounds in the attapulgite powder in the acid solution as the iron source for magnetic particles. In the present invention, the attapulgite nanorod crystal suspension containing iron ions is mixed with biochar. The attapulgite nanorod crystal suspension containing iron ions can perform acid etching modification on biochar. On the one hand, it improves the pore structure of biochar, increases its specific surface area and pore volume; on the other hand, rich active sites such as carboxyl groups are formed on the surface of biochar after acid etching modification, which can combine with iron ions in the attapulgite nanorod crystal suspension containing iron ions through chelation, so that the iron ions are firmly bound on the surface and pores of biochar; during the drying process, due to the high specific surface area of biochar, it can provide rich attachment sites for attapulgite nanorod crystals and prevent the re-aggregation of attapulgite nanorod crystals during drying. In the present invention, by pyrolyzing the precursor powder in an inert atmosphere, the iron ions adsorbed in the pores and on the surface of biochar can be transformed into magnetic iron particles, making the carbon-based attapulgite composite material have excellent magnetic properties. The results of the examples show that the magnetic carbon-based attapulgite composite material prepared by the present invention has excellent adsorption capacity and recovery effect for organic pollutant wastewater. Description of the Drawings
[0017] Figure 1 It is a picture of the recovery effect of the magnetic carbon-based attapulgite composite material prepared in Example 1 of the present invention in water; Figure 2 It is an SEM image of the magnetic carbon-based attapulgite composite material prepared in Example 2 of the present invention; Figure 3 It is a comparative effect picture of the adsorption of organic pollutants by the modified attapulgite powder prepared in Comparative Example 1 and the magnetic carbon-based attapulgite composite material prepared in Example 2 of the present invention; Figure 4 It is the adsorption agent cycle stability curve of the magnetic carbon-based attapulgite composite material prepared in Example 2 of the present invention. Detailed Embodiments
[0018] The present invention provides a method for preparing a magnetic carbon-based attapulgite composite material, comprising the following steps: (1) Mixing attapulgite powder with an acid solution, performing acid etching treatment to obtain an attapulgite nanorod crystal suspension containing iron ions; (2) Mix and dry the attapulgite nanorod crystal suspension containing iron ions obtained in step (1) and biochar in sequence to obtain a precursor powder. (3) Pyrolyze the precursor powder obtained in step (2) in an inert atmosphere to obtain a magnetic carbon-based attapulgite composite material.
[0019] In the present invention, attapulgite powder is mixed with an acid solution and subjected to acid etching treatment to obtain an attapulgite nanorod crystal suspension containing iron ions.
[0020] In the present invention, the mass content of iron in the attapulgite powder is preferably 5-10%, more preferably 6-8%. In the present invention, the attapulgite powder contains an iron compound. By using the attapulgite powder with the above iron content, the iron content is relatively high, and the prepared magnetic carbon-based attapulgite composite material can have good magnetism without adding external iron elements.
[0021] In the present invention, the particle size of the attapulgite powder is preferably <5 mm, more preferably <1 mm. By using the attapulgite powder with the above particle size, it is more conducive to the full contact between the acid solution and the attapulgite powder, thereby improving the dissociation effect.
[0022] The present invention has no special limitation on the source of the attapulgite powder, and any attapulgite powder that can be obtained by those skilled in the art can be used.
[0023] In the present invention, the source of the attapulgite powder is preferably obtained by ball milling natural attapulgite ore.
[0024] The present invention preferably first crushes natural attapulgite ore into granular attapulgite and then performs ball milling. By crushing in the present invention, the particle size of natural attapulgite ore can be initially reduced, and the subsequent ball milling efficiency can be improved. In the present invention, the particle size of the granular attapulgite is preferably 5-10 mm, more preferably 5-8 mm.
[0025] In the present invention, the rotation speed of the ball milling is preferably 1000-2000 rpm, more preferably 1500-2000 rpm; the ball milling time is preferably 2-6 h, more preferably 3-5 h. By controlling the ball milling parameters within the above range in the present invention, it is more conducive to fully reducing the particle size of natural attapulgite ore and forming attapulgite powder with a particle size meeting the requirements.
[0026] In the present invention, the acid solution preferably comprises one or more of hydrochloric acid, sulfuric acid, oxalic acid, and citric acid, and more preferably hydrochloric acid, sulfuric acid, or oxalic acid. In the present invention, the mass concentration of the acid solution is preferably 1-5%. In the examples of the present invention, the mass concentration of the acid solution can be 1%, 2%, 3%, 4%, or 5%. By using the acid solution with the above mass concentration in the present invention, it is more conducive to improving the acid etching effect on attapulgite powder, fully dissociating the attapulgite powder into an attapulgite nanorod crystal suspension containing iron ions, and fully dissolving the iron compounds in the attapulgite powder.
[0027] In the present invention, when the mass concentration of the acid solution is 1-5%, the mass ratio of the attapulgite powder to the volume of the acid solution is preferably (100-150) g:(500-600) mL. In the examples of the present invention, the mass ratio of the attapulgite powder to the volume of the acid solution can be 100 g:500 mL, 120 g:600 mL, or 150 g:600 mL. By controlling the mass ratio of the attapulgite powder to the volume of the acid solution within the above range in the present invention, it is more conducive to the full dissociation of the attapulgite powder.
[0028] The present invention has no special limitation on the method of mixing the attapulgite powder and the acid solution. A conventional mixing method can be used to make the two mix evenly. In the examples of the present invention, the method of mixing the attapulgite powder and the acid solution is preferably stirring.
[0029] In the present invention, the temperature of the acid etching treatment is preferably 25-150 °C; more preferably 40-100 °C; the time of the acid etching treatment is preferably 2-24 h, more preferably 3-10 h. By performing the acid etching treatment at the above temperature and time in the present invention, it can promote the full dissociation of the acid solution on the attapulgite powder.
[0030] In the present invention, the acid etching treatment is preferably carried out under stirring. By stirring in the present invention, the contact between the attapulgite powder and the acid solution can be made more sufficient, improving the dissociation efficiency. The present invention has no special limitation on the rotation speed of the stirring, and it can be adjusted according to needs as long as the attapulgite powder can be evenly dispersed in the acid solution during the acid etching treatment. After obtaining the attapulgite nanorod crystal suspension containing iron ions, the present invention mixes and dries the attapulgite nanorod crystal suspension containing iron ions and biochar in sequence to obtain a precursor powder.
[0031] In the present invention, the particle size of the biochar is preferably ≤50 mm, more preferably 10-40 mm; the specific surface area of the biochar is preferably ≥20 m 2 / g, more preferably 40-120 m 2 / g, and further preferably 65-120 m 2 / g. The biochar with the above parameters is adopted in the present invention, which has a relatively high specific surface area and a relatively small particle size, and can provide abundant attachment sites for attapulgite nanorods and iron ions; moreover, its relatively high specific surface area can also improve the adsorption capacity for pollutants when the magnetic carbon-based attapulgite composite material is used for wastewater treatment.
[0032] In the present invention, the mass ratio of the attapulgite powder to the biochar is preferably 1:(0.2 - 3), more preferably 1:(0.2 - 2). In the embodiments of the present invention, the mass ratio of the attapulgite powder to the biochar can be 1:0.4, 1:0.5 or 1:0.67. By controlling the mass ratio of the attapulgite powder to the biochar within the above range in the present invention, after the attapulgite powder dissociates, it can be fully and evenly adsorbed on the surface and pores of the biochar.
[0033] In the present invention, the method for mixing the suspension of attapulgite nanorods containing iron ions with the biochar is preferably ultrasonic. Through ultrasonic treatment in the present invention, it can promote the uniform mixing of the suspension of attapulgite nanorods containing iron ions and the biochar, so that the attapulgite nanorods and iron ions are fully adsorbed in the biochar. There are no special limitations on the power and time of the ultrasonic treatment in the present invention. By using a conventional ultrasonic device for adjustment, it can make the suspension of attapulgite nanorods containing iron ions and the biochar be mixed evenly. In the embodiments of the present invention, the ultrasonic time can be 10 min, 15 min or 20 min.
[0034] In the present invention, the drying temperature is preferably 60 - 80 °C, more preferably 65 - 80 °C, and further preferably 70 - 80 °C; the drying time is preferably 8 - 24 h, more preferably 12 h. After mixing the suspension of attapulgite nanorods containing iron ions with the biochar in the present invention, the obtained mixed suspension does not need to be filtered, but is directly dried at the above temperature and time. During the drying process, not only can the solvent after mixing the suspension of attapulgite nanorods containing iron ions and the biochar be fully removed, but also the acidic solvent in the suspension of attapulgite nanorods containing iron ions can be used to modify the biochar, improving the binding ability of the attapulgite nanorods and iron ions in the biochar, and obtaining a dried precursor powder.
[0035] After obtaining the precursor powder, the present invention performs pyrolysis treatment on the precursor powder in an inert atmosphere to obtain a magnetic carbon-based attapulgite composite material.
[0036] In the present invention, the inert atmosphere is preferably nitrogen or an inert gas, and the inert gas is preferably argon. In the present invention, as a protective gas, the inert atmosphere can prevent the precursor powder from being overpyrolyzed.
[0037] In the present invention, the temperature of the pyrolysis treatment is preferably 400 - 700 °C. In the embodiments of the present invention, the temperature of the pyrolysis treatment can be 500 °C, 550 °C or 600 °C; the time of the pyrolysis treatment is preferably 1 - 5 h, more preferably 3 - 4 h. By performing the pyrolysis treatment at the above temperatures and times, the iron ions can be fully converted into magnetic iron particles.
[0038] The method provided by the present invention is simple to operate and easy to control. It can utilize the iron ions in the attapulgite powder as the iron source of the magnetic carbon-based attapulgite composite material, and use biochar as the carrier of magnetic particles and attapulgite nanorods, thereby improving the stability of the magnetic carbon-based attapulgite composite material.
[0039] The present invention also provides a magnetic carbon-based attapulgite composite material prepared by the preparation method described in the above technical solution.
[0040] In the present invention, the magnetic carbon-based attapulgite composite material includes attapulgite nanorods, magnetic particles and biochar, and the attapulgite nanorods and magnetic particles are distributed on the surface and in the pores of the biochar.
[0041] For the magnetic carbon-based attapulgite composite material provided by the present invention, the attapulgite nanorods and magnetic particles are distributed on the surface and in the pores of the biochar. The binding ability between the magnetic particles and the biochar is relatively strong, and the attapulgite nanorods are not easily re-aggregated during use in water or after drying and recovery. Therefore, it can maintain good use stability and adsorption effect.
[0042] The present invention also provides the application of the magnetic carbon-based attapulgite composite material described in the above technical solution in treating organic wastewater.
[0043] The present invention has no special limitation on the method for applying the magnetic carbon-based attapulgite composite material in treating organic wastewater, and any method for treating wastewater using a conventional adsorbent can be adopted.
[0044] Since the magnetic carbon-based attapulgite composite material provided by the present invention has good magnetic stability and adsorption capacity, it has good adsorption property and recyclability when used for treating organic wastewater.
[0045] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts belong to the scope of protection of the present invention.
[0046] Example 1 A preparation method of a magnetic carbon-based attapulgite composite material, the steps are as follows: (1) Take 100 g of natural attapulgite ore, crush it to a particle size less than 5 mm using a jaw crusher to obtain granular attapulgite; place the granular attapulgite in a ball mill, use steel balls for ball milling at a rotational speed of 1500 rpm for 4 h to obtain attapulgite powder; mix the attapulgite powder with 500 mL of 3% hydrochloric acid solution, stir at 80 °C for 2 h for acid etching treatment to obtain an attapulgite nanorod crystal suspension containing iron ions; (2) Ultrasonically treat the attapulgite nanorod crystal suspension containing iron ions obtained in step (1) and 40 g of biochar with a particle size ≤ 40 mm and a specific surface area of 120 m 2 / g for 10 min using an ultrasonic cleaner, and dry it at 70 °C for 12 h to obtain a precursor powder; (3) Pyrolyze the precursor powder obtained in step (2) at 600 °C for 3 h in a nitrogen atmosphere to obtain a magnetic carbon-based attapulgite composite material; after testing, its specific surface area is 160 m 2 / g.
[0047] Disperse the magnetic carbon-based attapulgite composite material prepared in this example in water, place a magnet on one side, and observe its recovery effect in water as shown Figure 1 shown. It can be seen from Figure 1 that the magnetic carbon-based attapulgite composite material prepared by the present invention can be enriched in water using a magnet, which enables it to be recycled using a magnet during use.
[0048] Example 2 A method for preparing a magnetic carbon-based attapulgite composite material, the steps are as follows: (1) Take 120 g of natural attapulgite ore, crush it to a particle size less than 5 mm using a jaw crusher to obtain granular attapulgite; place the granular attapulgite in a ball mill, use steel balls for ball milling at a rotational speed of 1800 rpm for 5 h to obtain attapulgite powder; mix the attapulgite powder with 600 mL of 4% oxalic acid solution, stir at 100 °C for 3 h for acid etching treatment to obtain an attapulgite nanorod crystal suspension containing iron ions; (2) Ultrasonically treat the attapulgite nanorod crystal suspension containing iron ions obtained in step (1) and 60 g of biochar with a particle size ≤ 10 mm and a specific surface area of 40 m 2 / g for 20 min using an ultrasonic cleaner, and dry it at 80 °C for 12 h to obtain a precursor powder; (3) Pyrolyze the precursor powder obtained in step (2) at 500 °C for 4 h in an argon atmosphere to obtain a magnetic carbon-based attapulgite composite material.
[0049] The scanning electron microscope image of the magnetic carbon-based attapulgite composite prepared in this example is as Figure 2 shown. In Figure 2 , the rod-shaped material is the attapulgite nanorod crystal obtained by acid etching of attapulgite powder, and the blocky material is biochar. From Figure 2 , it can be seen that the attapulgite nanorod crystals are evenly distributed on the surface and in the pores of the biochar.
[0050] Example 3 A preparation method of a magnetic carbon-based attapulgite composite, the steps are as follows: (1) Take 150 g of natural attapulgite ore, crush it to a particle size of less than 5 mm using a jaw crusher to obtain granular attapulgite; place the granular attapulgite in a ball mill, use steel balls for ball milling, the rotation speed is 1000 rpm, and the ball milling time is 3 h to obtain attapulgite powder; mix the attapulgite powder with 500 mL of 2% sulfuric acid solution, stir at 40 °C for 2 h for acid etching treatment to obtain a suspension of attapulgite nanorod crystals containing iron ions; (2) Ultrasonically treat the suspension of attapulgite nanorod crystals containing iron ions obtained in step (1) with 100 g of biochar with an average particle size of 20 mm and a specific surface area of 65 m 2 / g for 15 min using an ultrasonic cleaner, and dry at 65 °C for 12 h to obtain a precursor powder; (3) Pyrolyze the precursor powder obtained in step (2) at 550 °C for 4 h in a nitrogen atmosphere to obtain a magnetic carbon-based attapulgite composite.
[0051] Comparative Example 1 A preparation method of modified attapulgite, the steps are as follows: (1) Take 120 g of natural attapulgite ore, crush it to a particle size of less than 5 mm using a jaw crusher to obtain granular attapulgite; place the granular attapulgite in a ball mill, use steel balls for ball milling, the rotation speed is 1800 rpm, and the ball milling time is 5 h to obtain attapulgite powder; mix the attapulgite powder with 600 mL of 4% oxalic acid solution, stir at 100 °C for 3 h for acid etching treatment to obtain a suspension of attapulgite nanorod crystals containing iron ions; (2) Dry the suspension of attapulgite nanorod crystals containing iron ions obtained in step (1) at 80 °C for 12 h to obtain a precursor powder; (3) Pyrolyze the precursor powder obtained in step (2) at 500 °C for 4 h in an argon atmosphere to obtain modified attapulgite.
[0052] Application Example 1 Prepare a metronidazole solution with a concentration of 20 mg / L, and set the solution volume to 100 mL. Weigh 0.1 g of the magnetic carbon-based attapulgite composite material prepared in Example 2 as the adsorbent, add it to the above metronidazole solution, stir well to mix, simulate the adsorption environment, and the adsorption process lasts for 24 h. Samples are taken and detected at 0 h, 0.5 h, 1 h, 2 h, 4 h, 8 h, 12 h, and 24 h respectively. The experimental results are as Figure 3 shown.
[0053] Comparative Application Example 1 The difference from Application Example 1 is that attapulgite powder prepared in step (1) of Example 1 of the present invention is used as the adsorbent, and the remaining operations are the same as those in Application Example 1. The obtained results are as Figure 3 shown.
[0054] Comparative Application Example 2 The difference from Application Example 1 is that the modified attapulgite prepared in Comparative Example 1 of the present invention is used as the adsorbent, and the remaining operations are the same as those in Application Example 1. The obtained results are as Figure 3 shown.
[0055] From Figure 3 it can be seen that after 24 h of adsorption equilibrium, when attapulgite powder is used as the adsorbent, the removal rate of metronidazole is only 23%. When the attapulgite in Comparative Example 1 ( Figure 3 is the original attapulgite) is used as the adsorbent, the removal rate of metronidazole is only 36%; when the magnetic carbon-based attapulgite composite material prepared in the present invention is used as the adsorbent, its removal rate of metronidazole is as high as 84%. This shows that the magnetic carbon-based attapulgite composite material prepared in the present invention has excellent performance advantages in adsorbing and removing the antibiotic metronidazole compared with attapulgite powder, and can purify water bodies containing such pollutants more efficiently.
[0056] Test Example Adsorbent cyclic stability experiment: Prepare a metronidazole solution with a concentration of 20 mg / L, and set the solution volume to 100 mL. Weigh 0.1 g of the magnetic carbon-based attapulgite composite material prepared in Example 2 as the adsorbent, add it to the above metronidazole solution, stir well to mix, simulate the adsorption environment, and the adsorption process lasts for 24 h. Samples are taken and detected at 0 h, 0.5 h, 1 h, 2 h, 4 h, 8 h, 12 h, and 24 h respectively. The experimental results are as Figure 4 shown. After the experiment, take out the adsorbent as the adsorbent, and conduct the adsorption experiment again according to the method of this test example to obtain the test results of the first cyclic use of the adsorbent; continue the experiment by this method to obtain the test results of the second cyclic use and the test results of the third cyclic use in turn. The experimental results are as Figure 4 shown. From Figure 4It can be seen that the magnetic carbon-based attapulgite composite material prepared by the present invention has excellent cycle stability as an adsorbent.
[0057] From the above results, it can be seen that the magnetic carbon-based attapulgite composite material prepared by the present invention has excellent adsorption capacity and recovery effect on organic pollutant wastewater. This is because the present invention uses acid solution to etch attapulgite powder, which can not only dissociate attapulgite powder into attapulgite nanorod crystals, but also dissolve iron compounds in attapulgite powder in the acid solution, and uses the iron in attapulgite powder as the iron source of magnetic particles; uses acid solution to modify biochar to improve the adsorption of biochar and iron ions, and then improve the binding ability of magnetic particles in biochar, and then make the magnetic carbon-based attapulgite composite material have better stability; during the drying process, due to the high specific surface area of biochar, it can provide rich attachment sites for attapulgite nanorod crystals and prevent the re-agglomeration of attapulgite nanorod crystals during drying. Therefore, the carbon-based attapulgite composite material prepared by the present invention has excellent adsorption capacity and recovery effect on organic pollutant wastewater.
[0058] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. A method for preparing a magnetic carbon-based attapulgite composite material, comprising the following steps: (1) mixing attapulgite powder with an acid solution and performing an acid etching treatment to obtain an attapulgite nanorod crystal suspension containing iron ions; (2) sequentially mixing and drying the attapulgite nanorod crystal suspension containing iron ions obtained in step (1) and biochar to obtain a precursor powder; (3) The precursor powder obtained in step (2) is subjected to pyrolysis treatment in an inert atmosphere to obtain a magnetic carbon-based attapulgite composite material.
2. The preparation method according to claim 1, characterized in that: The mass content of iron in the attapulgite powder in step (1) is 5-10%.
3. The preparation method according to claim 1, characterized in that: The acid solution in step (1) includes one or more of hydrochloric acid, sulfuric acid, oxalic acid and citric acid.
4. The preparation method according to claim 1 or 3, characterized in that: The mass concentration of the acid solution in step (1) is 1-5%.
5. The preparation method according to claim 1, characterized in that: The temperature of the acid etching treatment in step (1) is 25-150° C. and the time of the acid etching treatment is 2-24 hours.
6. The preparation method according to claim 1, characterized in that: The particle size of the biochar in step (2) is ≤50 mm, and the specific surface area of the biochar is ≥20 m 2 / g.
7. The preparation method according to claim 1 or 6, characterized in that: The mass ratio of the attapulgite powder in step (1) to the biochar in step (2) is 1:(0.2-3).
8. The preparation method according to claim 1, characterized in that: The temperature of the pyrolysis treatment in step (3) is 400-700° C. and the time of the pyrolysis treatment is 1-5 hours.
9. The magnetic carbon-based attapulgite composite material prepared by the preparation method according to any one of claims 1 to 8.
10. Use of the magnetic carbon-based attapulgite composite material according to claim 9 in treating organic wastewater.