Preparation method and application of magnetic hydrothermal carbon adsorbent
Magnetic hydrothermal carbon adsorbents were prepared by hydrothermal method, which solved the problem of resource waste and environmental pollution in red mud and peanut shell treatment, achieved efficient resource utilization and low-energy waste conversion, and had excellent adsorption performance and Magnetic response performance.
Patent Information
- Application Number
- CN202411571525.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-01-14
AI Technical Summary
The treatment of solid waste such as red mud and peanut shells has problems of resource waste and environmental pollution, and it is difficult for the existing technology to achieve its efficient reduction treatment and resource utilization.
Using red mud and peanut shells as raw materials, magnetic hydrothermal carbon adsorbents are prepared by hydrothermal method, including mixing red mud and peanut shell powder and adding NaOH solution for hydrothermal reaction, and undergoing solid-liquid separation, washing and drying treatment. , a magnetic hydrothermal carbon adsorbent with excellent adsorption properties and magnetic properties was produced.
The coordinated transformation of red mud and peanut shells has been achieved, the resource utilization efficiency of waste has been improved, and it has low energy consumption and environmental protection characteristics. It can effectively adsorb a variety of organic pollutants and achieve rapid separation and recycling through magnetic fields.
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Figure CN119303547A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of adsorbent preparation, and in particular to a preparation method and application of a magnetic hydrothermal carbon adsorbent. Background Art
[0002] Red mud is a type of solid waste with huge production volume. It is produced in the process of using caustic soda to extract alumina from bauxite. It is mainly divided into sintering red mud and Bayer red mud. Red mud itself contains a large amount of mineral elements (mainly Fe and Al) and strong alkalinity (pH is about 11). Therefore, it is easy to cause pollution of soil, groundwater and surface water in disposal and storage sites. If it is not properly handled, it will cause serious harm to human health and the ecological environment.
[0003] China is a large agricultural country, and the residues from agricultural production in China are an important part of biomass resources. At present, incineration, burial and stacking are the main ways to deal with these agricultural residues. Peanuts are a major oil crop and export agricultural product, and are also an important raw material for edible vegetable oil. However, except for a small part of peanut shells used as raw materials for papermaking or chemical products, roughage and fertilizers, most of China's peanut shells are discarded as solid waste or directly incinerated, causing waste of resources and environmental pollution. Therefore, it is urgent to develop a new red mud and peanut shell treatment technology to achieve the reduction and resource utilization of red mud and peanut shells. Summary of the invention
[0004] The purpose of the present invention is to provide a preparation method and application of a magnetic hydrothermal carbon adsorbent, which uses red mud and peanut shells as raw materials to prepare the magnetic hydrothermal carbon adsorbent, and can achieve the reduction treatment and resource utilization of red mud and peanut shells.
[0005] The technical solution adopted by the present invention is:
[0006] A method for preparing a magnetic hydrothermal carbon adsorbent comprises the following steps:
[0007] (1) using red mud and peanut shells as raw materials to prepare red mud powder and peanut shell powder respectively;
[0008] (2) mixing red mud powder and peanut shell powder to obtain a mixed powder;
[0009] (3) adding NaOH solution to the mixed powder, stirring evenly, and then transferring to a hydrothermal reactor for hydrothermal reaction;
[0010] (4) After the hydrothermal reaction, solid-liquid separation is performed, and the solid phase product is washed and dried to obtain a magnetic hydrothermal carbon adsorbent.
[0011] Preferably, in step (1): the red mud is high iron red mud with a TFe grade of 30% to 50%; and the red mud powder and peanut shell powder with a particle size of less than 0.038 mm account for ≥70% of the total mass.
[0012] Preferably, in step (1): before grinding the two solid waste raw materials of red mud and peanut shells, the red mud and peanut shells need to be dried separately, the drying temperature is 80-105° C., and the drying time is 12-24 hours.
[0013] Preferably, in step (2), the mass ratio of red mud powder to peanut shell powder in the mixed powder is 1:1-1:5.
[0014] Preferably, in step (3): the concentration of the NaOH solution is 3-5 mol / L, and the liquid-solid mass ratio of the NaOH solution to the mixed powder is 6:1-14:1.
[0015] Preferably, in step (3), the hydrothermal reaction temperature is 180-240° C., and the hydrothermal reaction time is 6-12 h.
[0016] Preferably, in step (4): solid-liquid separation is performed using a vacuum filter; the solid phase product is washed using deionized water and anhydrous ethanol until the outflowing liquid is colorless and transparent; and drying is performed in a vacuum drying oven at a drying temperature of 80-105° C. for a drying time of 10-12 h.
[0017] Application of the magnetic hydrothermal carbon adsorbent prepared as above in the adsorption of methylene blue.
[0018] The beneficial technical effects of the present invention are:
[0019] The present invention innovatively realizes the synergistic transformation and high value-added utilization of two industrial and agricultural solid wastes, red mud and peanut shells, and prepares a magnetic hydrothermal carbon adsorbent with excellent adsorption performance and magnetic properties through a hydrothermal method. This method significantly improves the resource utilization efficiency of waste and realizes the organic combination of solid waste reduction and resource utilization.
[0020] The present invention innovatively adopts a one-step hydrothermal synthesis method to achieve efficient composite of carbon materials and magnetic iron under mild conditions (compared to the traditional pyrolysis method). This method has the following advantages: mild reaction conditions and low energy consumption, avoiding the high temperature and high energy consumption problems of the traditional pyrolysis method; short reaction time and high conversion efficiency; the process is green and environmentally friendly, significantly reducing carbon emissions. The surface of the prepared magnetic hydrothermal carbon adsorbent is rich in various oxygen-containing functional groups such as carboxyl and hydroxyl, providing abundant active sites for the removal of pollutants; the magnetic hydrothermal carbon adsorbent has excellent magnetic response performance, and can be quickly separated and recovered by an external magnetic field; the magnetic hydrothermal carbon adsorbent exhibits excellent adsorption performance and recycling performance for various organic pollutants such as methylene blue.
[0021] The hydrothermal method used in the present invention can significantly enhance the mass transfer efficiency between biomass components and fluids, improve the material diffusion coefficient and solubility, reduce the system viscosity, and promote the homogeneous mixing of organic matter and gas. This process can effectively avoid the problems of coke generation in traditional processes.
[0022] The preparation method of the present invention has the advantages of short process, high efficiency, low energy consumption, etc., and has significant prospects for large-scale industrial application. Its characteristics include: (1) wide source of raw materials and low cost; (2) simple and efficient process; (3) excellent product performance and easy recycling; (4) environmentally friendly and in line with the requirements of green and sustainable development. The method has broad application prospects in the fields of environmental governance and resource recycling. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a schematic diagram of the process of preparing the magnetic hydrothermal carbon adsorbent of the present invention;
[0024] Figure 2 This is a scanning electron microscope image of the magnetic hydrothermal carbon adsorbent prepared in Example 1 of the present invention;
[0025] Figure 3 This is a graph showing the change in magnetization intensity of the magnetic hydrothermal carbon adsorbent obtained in Example 1 of the present invention with the strength of the external magnetic field;
[0026] Figure 4 Comparison of the removal rates of methylene blue by magnetic hydrothermal carbon adsorbent prepared by changing the mass ratio of red mud and peanut shell. DETAILED DESCRIPTION
[0027] The present invention will be further described below in conjunction with specific embodiments.
[0028] Example 1
[0029] A method for preparing a magnetic hydrothermal carbon adsorbent comprises the following steps:
[0030] (1) Industrial solid waste high-iron red mud with an iron grade TFe of 48.18% and agricultural solid waste peanut shells are used as raw materials, and are first dried at 100°C for 12 hours. Then, the red mud powder and the peanut shell powder are ground until the particle size of -0.038 mm accounts for ≥70% of the total mass, thereby obtaining red mud powder and peanut shell powder.
[0031] (2) Mixing red mud powder and peanut shell powder to obtain mixed powder. The mass ratio of red mud powder to peanut shell powder in the mixed powder is 1:3.
[0032] (3) Adding NaOH solution to the mixed powder, the concentration of the NaOH solution is 4 mol / L, the liquid-to-solid mass ratio of the NaOH solution to the mixed powder is 8:1, stirring evenly at room temperature, and then transferring to a hydrothermal reactor for hydrothermal reaction, the hydrothermal reaction temperature is 200° C., and the hydrothermal reaction time is 10 h.
[0033] (4) After the hydrothermal reaction, a vacuum filter is used to separate the solid and liquid. The solid phase product is washed with deionized water and anhydrous ethanol until the outflowing liquid is colorless and transparent, and then placed in a vacuum drying oven for drying at a temperature of 90° C. for 10 h to obtain a magnetic hydrothermal carbon adsorbent.
[0034] Example 2
[0035] A method for preparing a magnetic hydrothermal carbon adsorbent comprises the following steps:
[0036] (1) Industrial solid waste high-iron red mud with an iron grade TFe of 35% and agricultural solid waste peanut shells are used as raw materials, which are first dried at 80°C for 24 hours. Then, the red mud powder and the peanut shell powder are ground until the particle size of -0.038 mm accounts for ≥70% of the total mass, thereby obtaining red mud powder and peanut shell powder.
[0037] (2) Mixing red mud powder and peanut shell powder to obtain mixed powder. The mass ratio of red mud powder to peanut shell powder in the mixed powder is 1:5.
[0038] (3) Adding NaOH solution to the mixed powder, the concentration of the NaOH solution is 5 mol / L, the liquid-to-solid mass ratio of the NaOH solution to the mixed powder is 14:1, stirring evenly at room temperature, and then transferring to a hydrothermal reactor for hydrothermal reaction, the hydrothermal reaction temperature is 240°C, and the hydrothermal reaction time is 12 h.
[0039] (4) After the hydrothermal reaction, a vacuum filter is used to separate the solid and liquid. The solid phase product is washed with deionized water and anhydrous ethanol until the outflowing liquid is colorless and transparent, and then placed in a vacuum drying oven for drying at a temperature of 105° C. for 10 h to obtain a magnetic hydrothermal carbon adsorbent.
[0040] Example 3
[0041] A method for preparing a magnetic hydrothermal carbon adsorbent comprises the following steps:
[0042] (1) Industrial solid waste high-iron red mud with an iron grade TFe of 40% and agricultural solid waste peanut shells are used as raw materials, which are first dried at 105°C for 12 hours. Then, the red mud powder and the peanut shell powder are ground until the particle size of -0.038 mm accounts for ≥70% of the total mass, thereby obtaining red mud powder and peanut shell powder.
[0043] (2) Mixing red mud powder and peanut shell powder to obtain mixed powder. The mass ratio of red mud powder to peanut shell powder in the mixed powder is 1:1.
[0044] (3) Adding NaOH solution to the mixed powder, the concentration of the NaOH solution is 3 mol / L, the liquid-to-solid mass ratio of the NaOH solution to the mixed powder is 6:1, stirring evenly at room temperature, and then transferring to a hydrothermal reactor for hydrothermal reaction, the hydrothermal reaction temperature is 180° C., and the hydrothermal reaction time is 6 h.
[0045] (4) After the hydrothermal reaction, a vacuum filter is used to separate the solid and liquid. The solid phase product is washed with deionized water and anhydrous ethanol until the outflowing liquid is colorless and transparent, and then placed in a vacuum drying oven for drying at a temperature of 80° C. for 12 h to obtain a magnetic hydrothermal carbon adsorbent.
[0046] Example 4
[0047] A method for preparing a magnetic hydrothermal carbon adsorbent comprises the following steps:
[0048] (1) Industrial solid waste high-iron red mud with an iron grade TFe of 45% and agricultural solid waste peanut shells are used as raw materials, which are first dried at 90°C for 15 hours. Then, the red mud powder and the peanut shell powder are ground until the particle size of -0.038 mm accounts for ≥70% of the total mass, thereby obtaining red mud powder and peanut shell powder.
[0049] (2) Mixing red mud powder and peanut shell powder to obtain mixed powder. The mass ratio of red mud powder to peanut shell powder in the mixed powder is 1:3.
[0050] (3) Adding NaOH solution to the mixed powder, the concentration of the NaOH solution is 4 mol / L, the liquid-to-solid mass ratio of the NaOH solution to the mixed powder is 10:1, stirring evenly at room temperature, and then transferring to a hydrothermal reactor for hydrothermal reaction, the hydrothermal reaction temperature is 220°C, and the hydrothermal reaction time is 8 h.
[0051] (4) After the hydrothermal reaction, a vacuum filter is used to separate the solid and liquid. The solid phase product is washed with deionized water and anhydrous ethanol until the outflowing liquid is colorless and transparent, and then placed in a vacuum drying oven for drying at a temperature of 90° C. for 10 h to obtain a magnetic hydrothermal carbon adsorbent.
[0052] Example 5
[0053] The preparation method is the same as that of Example 1, except that the mass ratio of the red mud powder to the peanut shell powder in the mixed powder is adjusted to 1:1.
[0054] Example 6
[0055] The preparation method is the same as that of Example 1, except that the mass ratio of the red mud powder to the peanut shell powder in the mixed powder is adjusted to 1:2.
[0056] Example 7
[0057] The preparation method is the same as that of Example 1, except that the mass ratio of the red mud powder to the peanut shell powder in the mixed powder is adjusted to 1:4.
[0058] Example 8
[0059] The preparation method is the same as that in Example 1, except that the mass ratio of the red mud powder to the peanut shell powder in the mixed powder is adjusted to 1:5.
[0060] The magnetic hydrothermal carbon adsorbent obtained in Example 1 was photographed using a scanning electron microscope. Figure 2 As shown. Figure 2 It can be seen that the flat plate shape is a typical hydrothermal carbon morphology, and the irregular bright particles on its surface are magnetic iron, indicating that the hydrothermal carbon and magnetic iron are successfully composited.
[0061] The magnetic hydrothermal carbon adsorbent obtained in Example 1 was tested for its magnetization strength. Figure 3 The saturation magnetization of the magnetic hydrothermal carbon adsorbent is 24emu / g, and its excellent magnetic properties can achieve rapid magnetic separation and recovery.
[0062] The methylene blue adsorption rate of the magnetic hydrothermal carbon adsorbents prepared in Examples 1, 5 to 8 was measured. The results are as follows: Figure 4 As shown. Figure 4 It can be seen that when the ratio of red mud to peanut shell is 1:3, the adsorption rate of methylene blue by the prepared magnetic hydrothermal carbon adsorbent is the best, which can reach 88.50%.
[0063] The parts not mentioned in the above methods can be realized by adopting or drawing on existing technologies.
[0064] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for preparing a magnetic hydrothermal carbon adsorbent, characterized in that The following steps are involved: (1) using red mud and peanut shells as raw materials to prepare red mud powder and peanut shell powder respectively; (2) mixing red mud powder and peanut shell powder to obtain a mixed powder; (3) adding NaOH solution to the mixed powder, stirring evenly, and then transferring to a hydrothermal reactor for hydrothermal reaction; (4) After the hydrothermal reaction, solid-liquid separation is performed, and the solid phase product is washed and dried to obtain a magnetic hydrothermal carbon adsorbent.
2. The method for preparing a magnetic hydrothermal carbon adsorbent according to claim 1, characterized in that: In step (1), the red mud is high iron red mud with a TFe content of 30% to 50%; the red mud powder and peanut shell powder with a particle size of less than 0.038 mm account for ≥70% of the total mass.
3. The method for preparing a magnetic hydrothermal carbon adsorbent according to claim 1, characterized in that: In step (1): before grinding the two solid waste raw materials of red mud and peanut shells, the red mud and peanut shells need to be dried respectively, the drying temperature is 80-105° C., and the drying time is 12-24 hours.
4. The method for preparing a magnetic hydrothermal carbon adsorbent according to claim 1, characterized in that: In step (2): the mass ratio of red mud powder to peanut shell powder in the mixed powder is 1:1-1:
5.
5. The method for preparing a magnetic hydrothermal carbon adsorbent according to claim 1, characterized in that: In step (3): the concentration of the NaOH solution is 3-5 mol / L, and the liquid-solid mass ratio of the NaOH solution to the mixed powder is 6:1-14:
1.
6. The method for preparing a magnetic hydrothermal carbon adsorbent according to claim 1, characterized in that: In step (3): the hydrothermal reaction temperature is 180-240° C., and the hydrothermal reaction time is 6-12 h.
7. The method for preparing a magnetic hydrothermal carbon adsorbent according to claim 1, characterized in that: In step (4): using a vacuum filter to separate the solid and the liquid; washing the solid phase product with deionized water and anhydrous ethanol until the outflowing liquid is colorless and transparent; drying in a vacuum drying oven at a drying temperature of 80-105° C. and a drying time of 10-12 h.
8. Use of the magnetic hydrothermal carbon adsorbent prepared according to any one of claims 1 to 7 in the adsorption of methylene blue.