An organic contaminant adsorbing material and a method for preparing the same

Abstract

The application relates to the technical field of water treatment, and discloses an organic pollutant adsorption material and a preparation method thereof, which comprises the following raw materials in parts by mass: 40-60 parts of magnetic biochar, 10-30 parts of lignin, 10-30 parts of polystyrene, 5-15 parts of aluminum sulfate and 10-30 parts of modified metal organic framework material. The application can solve the problems of small specific surface area, large recycling difficulty and poor adsorption effect of the adsorption material used in the existing adsorption method, the organic pollutant adsorption material has the characteristics of high specific surface area, porous structure, multiple functional groups, high adsorption capacity, high selectivity and easy recycling, can effectively remove the organic pollutants in water, and does not cause secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to an organic pollutant adsorption material and its preparation method. Background Technology

[0002] Organic pollutants encompass both naturally occurring organic matter and various artificially processed or synthesized organic substances. They are diverse, including volatile organic compounds (VOCs), pesticides and insecticides, various chemical solvents, pharmaceuticals, organic dyes, and chemical products. Organic pollutants can enter the water cycle through multiple channels and in various forms, and are transported and even accumulated along the food chain. Because most organic pollutants possess high chemical stability and are difficult to decompose naturally, their large-scale accumulation in ecosystems leads to persistent pollution that directly endangers human health, becoming a global ecological security issue.

[0003] Organic pollutants in water are a complex class of compounds that can originate from various sources, including agriculture, industry, and urban life. These organics pose a serious threat to aquatic ecosystems and human health. Therefore, finding effective treatment methods to remove these pollutants is a crucial task in the field of water treatment.

[0004] Among various water treatment technologies, adsorption is widely considered an effective method for treating organic pollutants. Its core principle relies on specific adsorbent materials that have the ability to adsorb organic pollutants from water onto their surfaces. This physical treatment technology is not only simple to operate but also offers advantages in terms of high efficiency and low cost, thus finding widespread application in industrial and municipal wastewater treatment.

[0005] However, the key to realizing this technology lies in finding and preparing suitable adsorbent materials. Currently, there are many different adsorbent materials to choose from, such as activated carbon, zeolite, and clay. Although these adsorbent materials have certain effects, they also have some problems. For example, although activated carbon has a strong adsorption capacity and can be recycled through thermal treatment or chemical methods, these processes are often costly and complex; zeolite, although inexpensive, has a relatively low adsorption capacity; and clay has poor selectivity and its adsorption effect on certain specific organic compounds is not ideal.

[0006] Therefore, the goal for industrial and urban wastewater treatment is to develop an efficient and recyclable adsorbent material for organic pollutants and its preparation method. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide an organic pollutant adsorption material and its preparation method, which solves the problems of small specific surface area, difficulty in recycling, and poor adsorption effect of the adsorption materials used in existing adsorption methods.

[0008] The present invention solves the above-mentioned technical problems through the following technical means:

[0009] In a first aspect, the present invention provides an organic pollutant adsorption material comprising the following raw materials in parts by weight: 40-60 parts magnetic biochar, 10-30 parts lignin, 10-30 parts polystyrene, 5-15 parts aluminum sulfate, and 10-30 parts modified metal-organic framework material.

[0010] Furthermore, the magnetic biochar comprises 50 parts, lignin 20 parts, polystyrene 20 parts, aluminum sulfate 10 parts, and modified metal-organic framework material 20 parts.

[0011] Among them, magnetic biochar is a carbon material with a well-developed pore structure and high specific surface area, which can provide a large number of adsorption sites and adsorption forces, providing an adsorption substrate and magnetic recovery capability for organic pollutant adsorption materials; lignin is a natural aromatic polymer with various functional groups such as hydroxyl, methoxy, and phenolic groups, which can form hydrogen bonds or π-π interactions with organic pollutants; polystyrene is a hydrophobic synthetic polymer with a rigid benzene ring structure, which can form hydrophobic interactions or π-π interactions with organic pollutants; aluminum sulfate is an inorganic salt that can undergo condensation reaction with lignin and polystyrene to form a cross-linked network structure, enhancing the stability and mechanical strength of the adsorption material; modified metal-organic framework materials have high specific surface area and adjustable pore structure, which can efficiently adsorb specific organic pollutants.

[0012] Furthermore, the method for preparing the magnetic biochar includes the following steps:

[0013] A1. Crush the biomass, sieve it with a mesh size of 50-100, and then dry it to ensure that the moisture content of the biomass is less than 10%.

[0014] A2. Microwave pyrolysis of dried biomass to produce biochar;

[0015] A3. Iron salts are mixed with alkaline solutions to generate ferrate precursors, which are then heat-treated at 500-600℃ for 1-3 hours in an inert gas environment to obtain magnetic particles.

[0016] A4. Mix biochar with magnetic particles, then add deionized water to form a slurry; process the slurry through a high-pressure homogenizer, controlling the pressure at 50-100MPa, and cycle the process 3-5 times.

[0017] A5. Add silane coupling agent and react, then dry at 95-105℃ for 11-13 hours to obtain the magnetic biochar.

[0018] Furthermore, the microwave pyrolysis in step A2 is performed for 2-4 hours within a microwave power range of 600-900W and a temperature range of 500-700℃.

[0019] Furthermore, the weight ratio of biochar to magnetic particles in step A4 is (2-4):1.

[0020] Biomass is not limited to bamboo or coconut shells; agricultural waste such as rice straw and corn stalks can also be considered to achieve resource reuse.

[0021] Biochar is prepared by pyrolyzing biomass materials. During this process, the organic components within the biomass are decomposed, forming a porous carbonaceous material that facilitates subsequent pollutant adsorption. Magnetic particles are generated through chemical methods; these particles possess excellent magnetic properties, facilitating recovery during water treatment. The biochar and magnetic particles are physically mixed, ensuring the magnetic particles are uniformly distributed within the porous structure of the biochar. This results in magnetic biochar with both high adsorption capacity and easy magnetic recovery. Furthermore, a silane coupling agent, such as γ-aminopropyltriethoxysilane, is added to react with the hydroxyl and carboxyl functional groups on the biochar surface, forming silicon-oxygen bonds. This improves the mechanical strength and heat resistance of the biochar, while also increasing its hydrophilicity, which further enhances the adsorption of pollutants in water.

[0022] This method for preparing magnetic biochar allows for individual optimization of the properties of both the biochar and the magnetic particles (such as particle size, porosity, and magnetism), resulting in more precise material control. Individually optimized magnetic particles can possess higher magnetism, facilitating the magnetic recovery of the final magnetic biochar in water treatment. This method provides superior control over material properties while ensuring efficient adsorption and easy-to-operate magnetic recovery capabilities, making it suitable for a wide range of water treatment applications.

[0023] Furthermore, the preparation method of the modified metal-organic framework material includes the following steps: drying the metal-organic framework material in a vacuum environment at a temperature of 75-85℃ for 11-13 hours; mixing the dried metal-organic framework material and the functionalizing agent in a certain proportion; reacting at 95-105℃ for 12-14 hours; filtering and washing; and then drying at 55-65℃ for 11-13 hours to obtain the modified metal-organic framework material.

[0024] Furthermore, the weight ratio of the metal-organic framework material to the functionalizing agent is 1:(2-4).

[0025] Furthermore, the functionalizing agent is an aminosilane compound.

[0026] Modified metal-organic frameworks (MOFs) are endowed with new chemical functionalities by the introduction of aminosilane compounds, thereby enhancing their adsorption capacity for organic pollutants.

[0027] Secondly, the present invention provides a method for preparing an organic pollutant adsorbent material, comprising the following steps:

[0028] S1. Mix lignin with dilute sulfuric acid, wash and dry to remove excess acidic substances, and obtain activated lignin;

[0029] S2. Mix the activated lignin, polystyrene, magnetic biochar and modified metal-organic framework material evenly to obtain a mixture;

[0030] S3. Add the mixture to the aqueous solution of aluminum sulfate and stir thoroughly to obtain a slurry;

[0031] S4. Pour the slurry into a mold, and after pressing, drying and heat treatment, obtain the organic pollutant adsorbent material.

[0032] The combination of the high adsorption capacity of modified metal-organic framework materials and the ease of recovery of magnetic biochar improves treatment efficiency and operational convenience. The structural role of lignin and polystyrene, combined with the flocculation function of aluminum sulfate, helps to enhance the overall performance of the materials and their ability to treat various organic pollutants.

[0033] The beneficial effects of this invention are:

[0034] (1) The organic pollutant adsorbent material of the present invention has the characteristics of high specific surface area, porous structure, multiple functional groups, high adsorption capacity, high selectivity and easy recycling, and can effectively remove organic pollutants in water, such as dyes, pesticides and drugs.

[0035] (2) The preparation method of the organic pollutant adsorbent material of the present invention is simple and has no secondary pollution. Various inexpensive biomass can be used as raw materials, and large-scale production and application of adsorbent materials can be realized.

[0036] (3) The organic pollutant adsorbent material of the present invention is magnetic and can be quickly separated and recovered by an external magnetic field, thereby improving adsorption efficiency and reducing operating costs.

[0037] (4) The organic pollutant adsorption material of the present invention has good stability and reusability, which extends the service life of the adsorption material and reduces the amount of waste to be treated. Detailed Implementation

[0038] The present invention will be described in detail below with reference to specific embodiments:

[0039] Biomass selection: corn stalks.

[0040] Example 1

[0041] Preparation of magnetic biochar:

[0042] A1. Crush the biomass, sieve it with a mesh size of 150, and then dry it to ensure that the moisture content of the raw material is less than 10%.

[0043] A2. The dried biomass is then subjected to microwave pyrolysis to produce biochar. The microwave pyrolysis conditions are: microwave power of 600W and temperature of 500℃ for 2 hours.

[0044] A3. Iron salts are mixed with alkaline solutions to generate ferrate precursors, which are then heat-treated at 500°C for 1 hour in an inert gas environment to obtain magnetic particles.

[0045] A4. Mix biochar and magnetic particles in a 2:1 ratio, then add an appropriate amount of deionized water to form a slurry. Process the slurry using a high-pressure homogenizer, controlling the pressure at 50 MPa, and repeat the process three times.

[0046] A5. The magnetic biochar was obtained by adding silane coupling agent and reacting, and then drying at 95°C for 11 hours.

[0047] Preparation of modified metal-organic framework materials:

[0048] The metal-organic framework material was dried in a vacuum environment at 75°C for 11 hours. The dried metal-organic framework material and the functionalizing agent were mixed in a 1:2 ratio and reacted at 95-105°C for 12-14 hours. After filtration and washing, the material was dried at 55-65°C for 11-13 hours to obtain the modified metal-organic framework material.

[0049] Preparation of the organic pollutant adsorption material in this embodiment:

[0050] S1. Mix 10g of lignin with dilute sulfuric acid, wash and dry to remove excess acidic substances, and obtain activated lignin.

[0051] S2. Mix the activated lignin, 10g polystyrene, 40g magnetic biochar and 10g modified metal-organic framework material evenly to obtain a mixture;

[0052] S3. Add the mixture to 5g of aluminum sulfate aqueous solution and stir thoroughly to obtain a slurry;

[0053] S4. Pour the slurry into a mold, and after pressing, drying and heat treatment, obtain the organic pollutant adsorbent material.

[0054] Example 2

[0055] Preparation of magnetic biochar:

[0056] A1. Crush the biomass, sieve it with a mesh size of 175, and then dry it to ensure that the moisture content of the raw material is less than 10%.

[0057] A2. The dried biomass is pyrolyzed in a microwave to produce biochar. The conditions for microwave pyrolysis are: microwave power of 750W and temperature of 600℃ for 3 hours.

[0058] A3. Iron salts are mixed with alkaline solutions to generate ferrate precursors, which are then heat-treated at 550°C for 2 hours in an inert gas environment to obtain magnetic particles.

[0059] A4. Mix biochar and magnetic particles in a 3:1 ratio, then add an appropriate amount of deionized water to form a slurry. Process the slurry using a high-pressure homogenizer, controlling the pressure at 75 MPa, and repeat the process 4 times.

[0060] A5. The magnetic biochar was obtained by adding silane coupling agent and reacting, and then drying at 100°C for 12 hours.

[0061] Preparation of modified metal-organic framework materials:

[0062] The metal-organic framework material was dried in a vacuum environment at 80°C for 12 hours. The dried metal-organic framework material and the functionalizing agent were mixed in a ratio of 1:3 and reacted at 100°C for 13 hours. After filtration and washing, the material was dried at 60°C for 12 hours to obtain the modified metal-organic framework material.

[0063] Preparation of the organic pollutant adsorption material in this embodiment:

[0064] S1. Mix 20g of lignin with dilute sulfuric acid, wash and dry to remove excess acidic substances, and obtain activated lignin.

[0065] S2. Mix the activated lignin, 20g polystyrene, 50g magnetic biochar and 20g modified metal-organic framework material evenly to obtain a mixture;

[0066] S3. Add the mixture to 10g of aluminum sulfate aqueous solution and stir thoroughly to obtain a slurry;

[0067] S4. Pour the slurry into a mold, and after pressing, drying and heat treatment, obtain the organic pollutant adsorbent material.

[0068] Example 3

[0069] Preparation of magnetic biochar:

[0070] A1. Crush the biomass, sieve it with a mesh size of 200, and then dry it to ensure that the moisture content of the raw material is less than 10%.

[0071] A2. The dried biomass is pyrolyzed in a microwave to produce biochar. The conditions for microwave pyrolysis are: microwave power of 900W and temperature of 700℃ for 4 hours.

[0072] A3. Iron salts are mixed with alkaline solutions to generate ferrate precursors, which are then heat-treated at 600°C for 3 hours in an inert gas environment to obtain magnetic particles.

[0073] A4. Mix biochar and magnetic particles in a 4:1 ratio, then add an appropriate amount of deionized water to form a slurry. Process the slurry using a high-pressure homogenizer, controlling the pressure at 100 MPa, and cycle the process 5 times.

[0074] A5. The magnetic biochar was obtained by adding silane coupling agent and reacting, and then drying at 105°C for 13 hours.

[0075] Preparation of modified metal-organic framework materials:

[0076] The metal-organic framework material was dried in a vacuum environment at 85°C for 13 hours. The dried metal-organic framework material and the functionalizing agent were mixed in a ratio of 1:4 and reacted at 105°C for 14 hours. After filtration and washing, the material was dried at 65°C for 13 hours to obtain the modified metal-organic framework material.

[0077] Preparation of the organic pollutant adsorption material in this embodiment:

[0078] S1. Mix 30g of lignin with dilute sulfuric acid, wash and dry to remove excess acidic substances, and obtain activated lignin.

[0079] S2. Mix the activated lignin, 30g polystyrene, 60g magnetic biochar and 30g modified metal-organic framework material evenly to obtain a mixture;

[0080] S3. Add the mixture to 15g of aluminum sulfate aqueous solution and stir thoroughly to obtain a slurry;

[0081] S4. Pour the slurry into a mold, and after pressing, drying and heat treatment, obtain the organic pollutant adsorbent material.

[0082] Comparative Example 1

[0083] The difference between this embodiment and Embodiment 2 is that magnetic biochar is replaced with ordinary biochar.

[0084] Comparative Example 2

[0085] The difference between this embodiment and Embodiment 2 is that the modified metal-organic framework material is replaced with an unmodified metal-organic framework material.

[0086] Comparative Example 3

[0087] The difference between this embodiment and Embodiment 2 is that the magnetic biochar is produced by mixing biomass with iron salts and then pyrolyzing the mixture.

[0088] Adsorption performance

[0089] The concentration of Congo red in the solution was determined using ultraviolet-visible spectrophotometry, with the absorbance of the supernatant measured at 340 nm. The concentration of the remaining Congo red solution in the solution was calculated based on the standard curve. The adsorption rate of the iron-modified vermiculite adsorbent for the Congo red solution was then calculated.

[0090] Q=(C0-Ce) / C0×100%(1)

[0091] Where Q: adsorption rate, %;

[0092] C0: Initial concentration of Congo red solution in the reaction system, mg / L;

[0093] Ce: Concentration of Congo red solution in the filtrate after adsorption equilibrium, mg / L.

[0094] 10g of the organic pollutant adsorbent material from Examples 1-3 and Comparative Examples 1-2 were weighed and placed in three 150mL Erlenmeyer flasks. 100mL of a 10mg / L Congo red solution was transferred to each flask. A rotor was placed in each Erlenmeyer flask and placed on a magnetic stirrer. The stirring speed was adjusted to 300r / min. After reacting for 60.0min, the mixture was centrifuged at 3000rpm for 10.0min. The supernatant was collected and filtered through a 0.45μm filter membrane. The absorbance of the remaining Congo red solution in the filtrate was measured using a UV-Vis spectrophotometer. The concentration of the remaining Congo red solution in the filtrate was calculated based on the standard curve. The adsorption rate of the organic pollutant adsorbent material for the Congo red solution was calculated using formula (1), and the results are shown in Table 1.

[0095] Table 1. Adsorption rates of Congo red solution in different embodiments

[0096]

[0097] As shown in Table 1, Example 2 exhibits the best performance. Observing the absorption rate data from Comparative Example 1 and Example 2, the absorption rate of the sample in Example 2 is significantly higher than that in Comparative Example 1. This result indicates that magnetic biochar demonstrates superior adsorption efficiency in removing relevant pollutants. This difference in adsorption efficiency not only highlights the superior performance of magnetic biochar but also further confirms its high efficiency in treating specific pollutants.

[0098] The absorption rate data from Comparative Example 2 and Example 2 showed that the absorption rate of the sample in Example 2 was significantly higher than that in Comparative Example 2. This result indicates that the modified metal-organic framework material has a better effect in removing Congo red solution, verifying the superiority of the modified metal-organic framework material in treating organic pollutants.

[0099] The absorption rate data from Comparative Example 3 and Example 2 show that the absorption rate of the sample in Example 2 is significantly higher than that of Comparative Example 3, indicating that the magnetic biochar prepared in this invention has a better adsorption rate.

[0100] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

Claims

1. An organic pollutant adsorbent material, characterized in that: The raw materials include the following parts by weight: 40-60 parts magnetic biochar, 10-30 parts lignin, 10-30 parts polystyrene, 5-15 parts aluminum sulfate, and 10-30 parts modified metal-organic framework material. The method for preparing the magnetic biochar includes the following steps: A1. Crush the biomass, sieve it (50-100 mesh), and then dry it to ensure the moisture content of the raw material is below 10%. A2. Microwave pyrolysis of dried biomass to produce biochar; A3. Iron salts are mixed with alkaline solutions to generate ferrate precursors, which are then heat-treated at 500-600℃ for 1-3 hours in an inert gas environment to obtain magnetic particles. A4. Mix biochar and magnetic particles in a certain proportion, then add an appropriate amount of deionized water to form a slurry. Process the slurry through a high-pressure homogenizer, with the pressure controlled at 50-100MPa, and cycle the process 3-5 times. A5. After adding silane coupling agent and reacting, the magnetic biochar is obtained by drying at 95-105℃ for 11-13 hours. The preparation method of the modified metal-organic framework material includes the following steps: drying the metal-organic framework material in a vacuum environment at a temperature of 75-85℃ for 11-13 hours; mixing the dried metal-organic framework material and the functionalizing agent in a certain proportion; reacting at 95-105℃ for 12-14 hours; filtering and washing; and then drying at 55-65℃ for 11-13 hours to obtain the modified metal-organic framework material. The functionalizing agent is an aminosilane compound; The preparation method includes the following steps: S1. Mix lignin with dilute sulfuric acid, wash and dry to remove excess acidic substances, and obtain activated lignin; S2. Mix the activated lignin, polystyrene, magnetic biochar and modified metal-organic framework material evenly to obtain a mixture; S3. Add the mixture to the aqueous solution of aluminum sulfate and stir thoroughly to obtain a slurry; S4. Pour the slurry into a mold, and after pressing, drying and heat treatment, obtain the organic pollutant adsorbent material.

2. The organic pollutant adsorption material according to claim 1, characterized in that: The raw materials include the following parts by weight: 50 parts magnetic biochar, 20 parts lignin, 20 parts polystyrene, 10 parts aluminum sulfate, and 20 parts modified metal-organic framework material.

3. The organic pollutant adsorption material according to claim 1, characterized in that: The conditions for microwave pyrolysis in step A2 are: microwave power of 600-900W and temperature of 500-700℃ for 2-4 hours.

4. The organic pollutant adsorption material according to claim 1, characterized in that: The weight ratio of biochar to magnetic particles in step A4 is (2-4):

1.

5. The organic pollutant adsorption material according to claim 1, characterized in that: The weight ratio of the metal-organic framework material to the functionalizing agent is 1:(2-4).

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