Carbon-based adsorbent material for groundwater remediation and method for preparing the same

Abstract

The application belongs to the technical field of groundwater remediation, and particularly relates to a carbon-based adsorption material for groundwater remediation and a preparation method thereof; wherein the carbon-based adsorption material for groundwater remediation comprises the following raw materials in parts by weight: 80-100 parts of a modified carbon material matrix, and 5-20 parts of a magnetic functional filler; in the modified carbon material matrix, the natural porous skeleton of diatomite and the active sites formed after carbonization of agricultural and forestry waste are complementary to each other, which not only provides stable structural support for the material, but also builds rich adsorption channels, laying a foundation for the transmission and enrichment of pollutants; the magnetic functional filler is prepared into a core-shell structure, the CuFe2O4 core endows the material with high-efficiency magnetic responsiveness, and the ZIF-90 shell layer realizes the targeted adsorption and enrichment of heavy metals and antibiotics by virtue of the regular channels and active sites, and at the same time, provides protection for CuFe2O4 to avoid the activity attenuation of CuFe2O4 in a complex environment.

Description

Technical Field

[0001] This invention belongs to the field of groundwater remediation technology, specifically relating to a carbon-based adsorbent material for groundwater remediation and its preparation method. Background Technology

[0002] With the rapid development of industry and agriculture, heavy metal ions and antibiotic pollutants continuously infiltrate groundwater through livestock wastewater discharge, agricultural non-point source pollution, and industrial wastewater leakage, forming a complex pollution situation that seriously threatens water resource security and ecosystem stability. These pollutants are characterized by stable structure, strong bioaccumulation, and difficulty in natural degradation. They not only disrupt the original ecological balance of groundwater but may also harm human health through the drinking water chain.

[0003] Adsorption methods have become one of the mainstream technologies for groundwater pollution remediation due to their advantages such as simple operation, controllable cost, and wide applicability. Among them, carbon-based adsorption materials (such as biochar and activated carbon) are widely used due to their wide availability, large specific surface area, and stable adsorption performance. However, traditional carbon-based adsorption materials have significant technical bottlenecks: on the one hand, the pore structure of virgin carbon materials is underdeveloped, resulting in poor selectivity for heavy metals and antibiotics, making it difficult to achieve efficient targeted removal of complex pollutants; on the other hand, most carbon-based materials lack magnetic response properties, making it difficult to quickly separate and recover them from water bodies after use, easily causing secondary pollution. Therefore, developing efficient and environmentally friendly groundwater remediation technologies and functional materials has become a core demand in the current environmental governance field, and is of great significance for breaking through the technical bottlenecks of groundwater complex pollution remediation and improving remediation efficiency and economy. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a carbon-based adsorbent material for groundwater remediation and its preparation method. This invention uses agricultural and forestry waste and diatomaceous earth as matrix raw materials, synergistically composited with magnetic functional fillers to endow the material with multiple properties, including highly efficient targeted adsorption of heavy metals and antibiotics, catalytic degradation of pollutants, and magnetically responsive separation. The rigid framework of diatomaceous earth provides structural support for the entire material, effectively inhibiting the aggregation of magnetic functional fillers and enhancing the material's resistance to erosion in groundwater seepage. The magnetic properties of CuFe2O4 endow the material with rapid separation capabilities under an external magnetic field, allowing for recycling without complex filtration equipment. This invention solves the technical problems of poor adsorption selectivity, limited functionality, and difficulty in separation and recycling after use in traditional carbon-based adsorbent materials.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention provides a carbon-based adsorbent material for groundwater remediation, comprising the following raw materials in parts by weight: 80-100 parts modified carbon material matrix and 5-20 parts magnetic functional filler.

[0007] The modified carbon material matrix comprises the following raw materials in the following mass ratio: diatomaceous earth: agricultural and forestry waste = 1:3-8;

[0008] The method for preparing the modified carbon material matrix includes the following steps:

[0009] (1) Soak the diatomaceous earth in a 5% hydrochloric acid solution for 2 hours to remove impurities and increase its porosity. Then wash it with deionized water until neutral and finally dry it completely in a 105°C forced-air drying oven. Dry the agricultural and forestry waste at 105°C to constant weight to obtain pretreated diatomaceous earth and agricultural and forestry waste.

[0010] (2) Place the pretreated diatomaceous earth and corn cob powder in a ball mill jar and ball mill for 30 min to make them initially mixed evenly to obtain mixed powder. Add the mixed powder to deionized water and ultrasonically disperse for 40 min to form a modified carbon material matrix.

[0011] Preferably, the agricultural and forestry waste is one or more of corn cobs, rice husks, wheat straw, and peanut shells.

[0012] The magnetic functional filler comprises raw materials in the following mass ratio: Fe(NO3)3·9H2O:Cu(NO3)2·3H2O:2-imidazolium formaldehyde:Zn(NO3)2·6H2O=8-10:2.5:7:15;

[0013] The method for preparing the magnetic functional filler includes the following preparation steps:

[0014] (a) Fe(NO3)3·9H2O, Cu(NO3)2·3H2O and sodium citrate were added to ethylene glycol in sequence and magnetically stirred for 1 h until completely dissolved. Then urea was added and stirred for another 30 min until dissolved. The mixture was transferred to a polytetrafluoroethylene reactor and placed in an oven. The reactor was kept at 180 °C for 8 h for a solvothermal reaction. After cooling to room temperature, the reactor was opened and a black precipitate was obtained. The black precipitate was collected and washed alternately with deionized water and anhydrous ethanol. The mixture was then vacuum dried at 60 °C for 6 h. The dried powder was calcined in a muffle furnace at 450 °C for 2 h in an air atmosphere and then ground through a 200-mesh sieve to form CuFe2O4 powder.

[0015] (b) Take 3 portions of anhydrous methanol, disperse CuFe2O4 powder in the first portion of anhydrous methanol, sonicate for 30 min to ensure full dispersion, and slowly add polyethyleneimine solution dropwise while continuously stirring. The ratio of CuFe2O4 powder, the first portion of anhydrous methanol and polyethyleneimine solution is 1 g: 25 mL: 2 mL to form a mixed system. Stir the mixed system at 50 °C for 2 h. After the reaction is complete, centrifuge for 5 min, collect the solid, wash it, and dry it in a vacuum drying oven to obtain modified CuFe2O4.

[0016] (c) All the modified CuFe2O4 was redispersed in the second part of anhydrous methanol. The ratio of modified CuFe2O4 to the second part of anhydrous methanol was 1g:50-75mL. 2-Imidazole formaldehyde was added and stirred for 1 h until it was completely dissolved to form a mixture. Zn(NO3)2·6H2O was weighed and dissolved in the third part of anhydrous methanol. The ratio of Zn(NO3)2·6H2O to the third part of anhydrous methanol was 3g:10mL to obtain a zinc nitrate methanol solution. Under vigorous stirring, the zinc nitrate methanol solution was slowly added dropwise to the mixture. After the addition was completed, the mixture was stirred continuously at room temperature for 24 h to form an emulsion.

[0017] (d) Centrifuge the emulsion, collect the precipitate, wash it, and dry it in a vacuum drying oven for 6 h to obtain the magnetic functional filler.

[0018] This invention also provides a method for preparing a carbon-based adsorbent material for groundwater remediation, specifically including the following steps:

[0019] S1. Magnetic functional filler is added to the modified carbon material matrix, sonicated for 20 min, and mechanically stirred for 1 h to ensure that the nanocomposite is uniformly dispersed in the matrix to form a uniform paste mixture with a solid-liquid ratio of about 1:3.

[0020] S2, the paste mixture is loaded into a specific mold and pressed into a disc with a diameter of about 1 cm under a pressure of 5 MPa. The disc is then placed in a 105℃ forced-air drying oven for 4 h to fully dry its surface in order to avoid cracking during the subsequent carbonization process, thus forming a dried disc.

[0021] S3. After drying, the discs were placed stably in the quartz boat of the tube furnace. The tube furnace was sealed, and high-purity nitrogen was introduced at a flow rate of 50 mL / min for 30 min to completely remove the air from the furnace. Under continuous nitrogen atmosphere protection, the temperature was increased to 600 ℃ at a programmed temperature control rate of 5 ℃ / min and carbonized at this temperature for 2 h. After carbonization, the power was cut off, and the tube furnace was allowed to cool naturally to room temperature under nitrogen atmosphere. The carbonized product was taken out, slightly crushed, and passed through a 100-mesh standard sieve. The sieved powder was washed with deionized water until neutral. Finally, the washed material was dried at 105 ℃ to obtain a carbon-based adsorbent material for groundwater remediation.

[0022] Compared with the prior art, the present invention achieves the following beneficial effects:

[0023] In the modified carbon material matrix of this invention, the natural porous framework of diatomaceous earth and the active sites formed after the carbonization of agricultural and forestry waste complement each other, providing stable structural support for the material and constructing abundant adsorption channels, laying the foundation for pollutant transport and enrichment. The uniform slurry formed by ball milling and ultrasonic dispersion provides a good carrier for the uniform dispersion of magnetic functional fillers, avoiding the agglomeration of functional components. The magnetic functional filler is prepared as a core-shell structure. The CuFe2O4 core endows the material with high-efficiency magnetic responsiveness, ensuring rapid separation and recovery after use. The ZIF-90 shell, with its regular channels and active sites, achieves targeted adsorption and enrichment of heavy metals and antibiotics, while protecting CuFe2O4 and preventing its activity decay in complex environments. Modification with polyethyleneimine solution strengthens the interfacial bonding between CuFe2O4 and ZIF-90, improving the stability of the core-shell structure. The targeted coordination sites of ZIF-90 specifically bind to heavy metal ions, and CuFe2O4 activates trace peroxides in the groundwater environment to generate free radicals, which completely degrade the adsorbed recalcitrant organic matter. The rigid framework of diatomaceous earth provides structural support for the entire material, effectively inhibiting the agglomeration of magnetic functional fillers and enhancing the material's resistance to erosion during groundwater seepage. The magnetism of CuFe2O4 endows the material with rapid separation capabilities under an external magnetic field, allowing for recycling and reuse without complex filtration equipment. The anchoring effect of the carbon-based matrix on the functional components ensures that the material maintains stable performance even after multiple cycles, significantly reducing remediation costs. From the perspective of green development and resource utilization, the material uses agricultural waste and natural diatomaceous earth as its main raw materials, achieving solid waste resource utilization. The preparation process leaves no toxic residues, aligning with the concept of ecological restoration. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the cyclic stability of the carbon-based adsorbent material for groundwater remediation prepared according to the present invention.

[0025] Figure 2 This is a SEM image of the magnetic functional filler prepared according to the present invention. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions of the present invention and to make the above-mentioned features, objectives, and advantages of the present invention clearer and easier to understand, the present invention will be further described below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0028] Unless otherwise specified, the following embodiments are all conventional methods; unless otherwise specified, the materials used in the following embodiments are all new materials purchased from the market.

[0029] Example 1: This example provides a carbon-based adsorbent material for groundwater remediation, which comprises the following raw materials in parts by weight: 80 parts modified carbon material matrix and 5 parts magnetic functional filler.

[0030] The modified carbon material matrix comprises the following raw materials in the following mass ratio: diatomaceous earth: rice husk = 1:3;

[0031] The method for preparing the modified carbon material matrix includes the following steps:

[0032] (1) Soak the diatomaceous earth in a 5% hydrochloric acid solution for 2 hours to remove impurities and increase its porosity. Then wash it with deionized water until neutral and finally dry it completely in a 105°C forced-air drying oven. Dry the rice husks at 105°C to constant weight to obtain pretreated diatomaceous earth and rice husks.

[0033] (2) Weigh the pretreated diatomaceous earth and rice husks according to the mass ratio of 1:3, place them in a ball mill jar, and ball mill them at 300 rpm for 30 min to make them initially mixed evenly, and obtain mixed powder. Add the mixed powder to 100 mL of deionized water, with a ratio of 1 g to 25 mL of mixed powder to deionized water, and ultrasonically disperse for 40 min to form a modified carbon material matrix.

[0034] The magnetic functional filler comprises raw materials in the following mass ratio: Fe(NO3)3·9H2O:Cu(NO3)2·3H2O:2-imidazolium formaldehyde:Zn(NO3)2·6H2O=8:2.5:7:15;

[0035] The method for preparing the magnetic functional filler includes the following preparation steps:

[0036] (a) Fe(NO3)3·9H2O, Cu(NO3)2·3H2O and sodium citrate were added to ethylene glycol in sequence and magnetically stirred for 1 h until completely dissolved. Then urea was added and stirred for another 30 min until dissolved. The mixture was transferred to a polytetrafluoroethylene reactor and placed in an oven. The reactor was kept at 180 °C for 8 h for a solvothermal reaction. After cooling to room temperature, the reactor was opened and a black precipitate was obtained. The black precipitate was collected using an external magnetic field and washed three times each with deionized water and anhydrous ethanol. The precipitate was then vacuum dried at 60 °C for 6 h and placed in a muffle furnace. The temperature was increased from room temperature to 450 °C at a rate of 5 °C / min under an air atmosphere and held at this temperature for 2 h for calcination. The precipitate was then ground through a 200-mesh sieve to form CuFe2O4 powder.

[0037] (b) Take anhydrous methanol and divide it into 3 portions. Disperse CuFe2O4 powder in the first portion of anhydrous methanol and sonicate it for 30 min to ensure it is fully dispersed. Under continuous stirring, slowly add polyethyleneimine solution. The ratio of CuFe2O4 powder, the first portion of anhydrous methanol and polyethyleneimine solution is 1 g: 25 mL: 2 mL to form a mixed system. Stir the mixed system at 50 °C for 2 h. After the reaction is complete, centrifuge at 8000 rpm for 5 min, collect the solid, wash it 3 times with anhydrous methanol, and dry the obtained solid in a vacuum drying oven at 60 °C to obtain modified CuFe2O4.

[0038] (c) All the modified CuFe2O4 was redispersed in the second part of anhydrous methanol. The ratio of modified CuFe2O4 to the second part of anhydrous methanol was 1 g: 50 mL. 2-Imidazole formaldehyde was added and stirred for 1 h until it was completely dissolved to form a mixture. Zn(NO3)2·6H2O was weighed and dissolved in the third part of anhydrous methanol. The ratio of Zn(NO3)2·6H2O to the third part of anhydrous methanol was 3 g: 10 mL. Under vigorous stirring, zinc nitrate methanol solution was slowly added dropwise to the mixture. After the addition was completed, the mixture was stirred continuously at room temperature for 24 h to form an emulsion.

[0039] (d) Centrifuge the emulsion at 10,000 rpm for 10 min, collect the precipitate, wash the precipitate repeatedly with anhydrous methanol 4 times, and then dry it in a vacuum drying oven at 80 ℃ for 6 h to obtain the magnetic functional filler.

[0040] This embodiment also provides a method for preparing a carbon-based adsorbent material for groundwater remediation, specifically including the following steps:

[0041] S1. Add magnetic functional filler to the modified carbon material matrix, sonicate for 20 min, and mechanically stir for 1 h to form a uniform paste mixture.

[0042] S2, the paste mixture is loaded into a specific mold and pressed into a round sheet with a diameter of about 1 cm and a thickness of 5 mm under a pressure of 5 MPa. The formed round sheet is placed in a 105℃ forced-air drying oven for 4 h to fully dry its surface and form a dried round sheet.

[0043] S3. After drying, the discs were placed stably in the quartz boat of a tube furnace. The tube furnace was sealed, and high-purity nitrogen was introduced at a flow rate of 50 mL / min. The furnace was continuously purged for 30 min to completely remove the air inside. Under the protection of a continuous nitrogen atmosphere, the temperature was increased from room temperature to 600 ℃ at a programmed temperature control rate of 5 ℃ / min, and carbonized at this temperature for 2 h. After carbonization, the power was cut off, and the material was allowed to cool naturally to room temperature. The carbonized product was removed, pulverized, and passed through a 100-mesh standard sieve. The sieved powder was washed with deionized water until neutral. Finally, it was dried at 105 ℃ to obtain a carbon-based adsorbent material for groundwater remediation.

[0044] Example 2: This example provides a carbon-based adsorbent material for groundwater remediation, which comprises the following raw materials in parts by weight: 90 parts modified carbon material matrix and 15 parts magnetic functional filler.

[0045] The modified carbon material matrix comprises raw materials in the following mass ratio: diatomaceous earth: corn cob = 1:5;

[0046] The method for preparing the modified carbon material matrix includes the following steps:

[0047] (1) Soak the diatomaceous earth in a 5% hydrochloric acid solution for 2 hours to remove impurities and increase its porosity. Then wash it with deionized water until neutral and finally dry it completely in a 105°C forced-air drying oven. Dry the corn cob at 105°C to constant weight to obtain pretreated diatomaceous earth and corn cob.

[0048] (2) Weigh the pretreated diatomaceous earth and corn cob according to the mass ratio of 1:3, place them in a ball mill jar, and ball mill them at 300 rpm for 30 min to make them initially mixed evenly to obtain mixed powder. Add the mixed powder to deionized water at a ratio of 1 g: 25 mL and ultrasonically disperse for 40 min to form a modified carbon material matrix.

[0049] The magnetic functional filler comprises raw materials in the following mass ratio: Fe(NO3)3·9H2O:Cu(NO3)2·3H2O:2-imidazolium formaldehyde:Zn(NO3)2·6H2O=9:2.5:7:15;

[0050] The method for preparing the magnetic functional filler includes the following preparation steps:

[0051] (a) Fe(NO3)3·9H2O, Cu(NO3)2·3H2O and sodium citrate were added to ethylene glycol in sequence and magnetically stirred for 1 h until completely dissolved. Then urea was added and stirred for another 30 min until dissolved. The mixture was transferred to a polytetrafluoroethylene reactor and placed in an oven. The reactor was kept at 180 °C for 8 h for a solvothermal reaction. After cooling to room temperature, the reactor was opened and a black precipitate was obtained. The black precipitate was collected using an external magnetic field and washed three times each with deionized water and anhydrous ethanol. The precipitate was dried under vacuum at 60 °C for 6 h and then placed in a muffle furnace. The temperature was increased from room temperature to 450 °C at a rate of 5 °C / min under an air atmosphere and held at this temperature for 2 h for calcination. The precipitate was then ground through a 200-mesh sieve to form CuFe2O4 powder.

[0052] (b) Take anhydrous methanol and divide it into 3 portions. Disperse CuFe2O4 powder in the first portion of anhydrous methanol and sonicate it for 30 min to ensure it is fully dispersed. Under continuous stirring, slowly add polyethyleneimine solution. The ratio of CuFe2O4 powder, the first portion of anhydrous methanol and polyethyleneimine solution is 1 g: 25 mL: 2 mL to form a mixed system. Stir the mixed system at 50 °C for 2 h. After the reaction is complete, centrifuge at 8000 rpm for 5 min, collect the solid, wash it 3 times with anhydrous methanol, and dry the obtained solid in a vacuum drying oven at 60 °C to obtain modified CuFe2O4.

[0053] (c) All the modified CuFe2O4 was redispersed in the second part of anhydrous methanol. The ratio of modified CuFe2O4 to the second part of anhydrous methanol was 1 g: 60 mL. 2-Imidazole formaldehyde was added and stirred for 1 h until it was completely dissolved to form a mixture. Zn(NO3)2·6H2O was weighed and dissolved in the third part of anhydrous methanol. The ratio of Zn(NO3)2·6H2O to the third part of anhydrous methanol was 3 g: 10 mL. Under vigorous stirring, zinc nitrate methanol solution was slowly added dropwise to the mixture. After the addition was completed, the mixture was stirred continuously at room temperature for 24 h to form an emulsion.

[0054] (d) Centrifuge the emulsion at 10,000 rpm for 10 min, collect the precipitate, wash the precipitate repeatedly with anhydrous methanol 4 times, and then dry it in a vacuum drying oven at 80 ℃ for 6 h to obtain the magnetic functional filler.

[0055] This embodiment also provides a method for preparing a carbon-based adsorbent material for groundwater remediation, specifically including the following steps:

[0056] S1. Add magnetic functional filler to the modified carbon material matrix, sonicate for 20 min, and mechanically stir for 1 h to form a uniform paste mixture.

[0057] S2, the paste mixture is loaded into a specific mold and pressed into a round sheet with a diameter of 1 cm and a thickness of 5 mm under a pressure of 5 MPa. The formed round sheet is placed in a 105℃ forced-air drying oven for 4 h to fully dry its surface and form a dried round sheet.

[0058] S3. After drying, the discs were placed stably in the quartz boat of a tube furnace. The tube furnace was sealed, and high-purity nitrogen was introduced at a flow rate of 50 mL / min. The furnace was continuously purged for 30 min to completely remove the air inside. Under the protection of a continuous nitrogen atmosphere, the temperature was increased from room temperature to 600 ℃ at a programmed temperature control rate of 5 ℃ / min, and carbonized at this temperature for 2 h. After carbonization, the power was cut off, and the material was allowed to cool naturally to room temperature. The carbonized product was removed, pulverized, and passed through a 100-mesh standard sieve. The sieved powder was washed with deionized water until neutral. Finally, it was dried at 105 ℃ to obtain a carbon-based adsorbent material for groundwater remediation.

[0059] Multiple Examples 3: An example provides a carbon-based adsorbent material for groundwater remediation, which comprises the following raw materials in parts by weight: 100 parts modified carbon material matrix and 20 parts magnetic functional filler.

[0060] The modified carbon material matrix comprises raw materials in the following mass ratio: diatomaceous earth: agricultural and forestry waste = 1:8;

[0061] The method for preparing the modified carbon material matrix includes the following steps:

[0062] (1) Soak the diatomaceous earth in a 5% hydrochloric acid solution for 2 hours to remove impurities and increase its porosity. Then wash it with deionized water until neutral and finally dry it completely in a 105°C forced-air drying oven. Dry the agricultural and forestry waste at 105°C to constant weight to obtain pretreated diatomaceous earth and agricultural and forestry waste.

[0063] (2) Weigh the pretreated diatomaceous earth and agricultural and forestry waste according to the mass ratio of 1:3, place them in a ball mill jar, and ball mill them at 300 rpm for 30 min to make them initially mixed evenly to obtain mixed powder. Add the mixed powder to deionized water at a ratio of 1 g: 25 mL and ultrasonically disperse for 40 min to form a modified carbon material matrix.

[0064] The agricultural and forestry waste is a mixture of corn cobs, rice husks, and wheat straw, with a mass ratio of 1:1.

[0065] The magnetic functional filler comprises raw materials in the following mass ratio: Fe(NO3)3·9H2O:Cu(NO3)2·3H2O:2-imidazolium formaldehyde:Zn(NO3)2·6H2O=10:2.5:7:15;

[0066] The method for preparing the magnetic functional filler includes the following preparation steps:

[0067] (a) Fe(NO3)3·9H2O, Cu(NO3)2·3H2O and sodium citrate were added to ethylene glycol in sequence and magnetically stirred for 1 h until completely dissolved. Then urea was added and stirred for another 30 min until dissolved. The mixture was transferred to a polytetrafluoroethylene reactor and placed in an oven. The reactor was kept at 180 °C for 8 h for a solvothermal reaction. After cooling to room temperature, the reactor was opened and a black precipitate was obtained. The black precipitate was collected using an external magnetic field and washed three times each with deionized water and anhydrous ethanol. The precipitate was then vacuum dried at 60 °C for 6 h and placed in a muffle furnace. The temperature was increased from room temperature to 450 °C at a rate of 5 °C / min under an air atmosphere and held at this temperature for 2 h for calcination. The precipitate was then ground through a 200-mesh sieve to form CuFe2O4 powder.

[0068] (b) Take anhydrous methanol and divide it into 3 portions. Disperse CuFe2O4 powder in the first portion of anhydrous methanol and sonicate it for 30 min to ensure it is fully dispersed. Under continuous stirring, slowly add polyethyleneimine solution. The ratio of CuFe2O4 powder, the first portion of anhydrous methanol and polyethyleneimine solution is 1 g: 25 mL: 2 mL to form a mixed system. Stir the mixed system at 50 °C for 2 h. After the reaction is complete, centrifuge at 9000 rpm for 5 min, collect the solid, wash it 3 times with anhydrous methanol, and dry the obtained solid in a vacuum drying oven at 60 °C to obtain modified CuFe2O4.

[0069] (c) All the modified CuFe2O4 was redispersed in the second part of anhydrous methanol. The ratio of modified CuFe2O4 to the second part of anhydrous methanol was 1 g: 75 mL. 2-Imidazole formaldehyde was added and stirred for 1 h until it was completely dissolved to form a mixture. Zn(NO3)2·6H2O was weighed and dissolved in the third part of anhydrous methanol. The ratio of Zn(NO3)2·6H2O to the third part of anhydrous methanol was 3 g: 10 mL. Under vigorous stirring, zinc nitrate methanol solution was slowly added dropwise to the mixture. After the addition was completed, the mixture was stirred continuously at room temperature for 24 h to form an emulsion.

[0070] (d) Centrifuge the emulsion at 10,000 rpm for 10 min, collect the precipitate, wash the precipitate repeatedly with anhydrous methanol 4 times, and then dry it in a vacuum drying oven at 80 ℃ for 6 h to obtain the magnetic functional filler.

[0071] This embodiment also provides a method for preparing a carbon-based adsorbent material for groundwater remediation, specifically including the following steps:

[0072] S1. Add magnetic functional filler to the modified carbon material matrix, sonicate for 20 min, and mechanically stir for 1 h to form a uniform paste mixture.

[0073] S2, the paste mixture is loaded into a specific mold and pressed into granules under a pressure of 5 MPa. The granules are then placed in a 105℃ forced-air drying oven for 4 hours to fully dry their surface and form dry granules.

[0074] S3. The dried granules were placed stably in a quartz boat in a tube furnace. The tube furnace was sealed, and high-purity nitrogen was introduced at a flow rate of 50 mL / min. The furnace was continuously purged for 30 min to completely remove the air inside. Under the protection of a continuous nitrogen atmosphere, the temperature was increased from room temperature to 600 °C at a programmed temperature control rate of 5 °C / min, and carbonized at this temperature for 2 h. After carbonization, the power was cut off, and the material was allowed to cool naturally to room temperature. The carbonized product was removed, pulverized, and passed through a 100-mesh standard sieve. The sieved powder was washed with deionized water until neutral. Finally, it was dried at 105 °C to obtain a carbon-based adsorbent material for groundwater remediation.

[0075] Comparative Example 1 differs from Example 2 in that the addition of diatomaceous earth was omitted, while the rest of the components are identical to Example 2.

[0076] Comparative Example 2 differs from Example 2 in that the addition of magnetic functional filler was omitted, while the rest of the components are identical to Example 2.

[0077] Comparative Example 3 differs from Example 2 in that the addition of 2-imidazolium formaldehyde was omitted, while the rest of the components are identical to those in Example 2.

[0078] Experimental example:

[0079] 1. Adsorption experiment

[0080] The carbon-based adsorbent materials for groundwater remediation prepared in Examples 1-3 and Comparative Examples 1-3 of this invention were used as samples for batch adsorption experiments in a constant-temperature shaker. Specifically, 50 mg of the sample was added to 50 mL of dye solution and shaken at a constant speed of 150 rpm for 2 h until adsorption equilibrium was reached. The concentrations of Pb(II), Cd(II), Cr(VI), and tetracycline were prepared to be 20 mg / mL. The dye concentration and its changes were determined by measuring the absorbance at their respective maximum wavelengths using a UV spectrophotometer. The dye removal efficiency (R, %) and dye adsorption capacity were calculated. The calculation formula is: R = (C0 - C...) t ) / C0×100%; where: C0 (mg / L) is the initial dye concentration, C t (mg / L) represents the equilibrium dye concentration at time t. The results are recorded in Table 1.

[0081] 2. Cyclic stability test

[0082] Using the carbon-based adsorbent materials for groundwater remediation prepared in Examples 1-3 and Comparative Examples 1-3 of this invention as samples, Pb(II) and tetracycline solutions were prepared at a concentration of 20 mg / mL. 50 mg of the sample was added, and adsorption was carried out for 120 min. Adsorption-desorption cycle experiments were conducted to analyze the cyclic regeneration performance of the carbon-based adsorbent materials for groundwater remediation. The adsorbed material was filtered and separated, then desorbed by adding 1 mol / L HCl solution for 30 min. After filtration, washing, and drying, the material was used for the next Pb(II) adsorption enrichment experiment. For the tetracycline cycle experiment, the adsorbed material was filtered and separated, then filtered, washed, and dried before the next adsorption enrichment experiment. The experiment was cycled 6 times, and the results are as follows: Figure 1 As shown.

[0083] Table 1: Adsorption rate data for different pollutants

[0084] ;

[0085] As shown in Table 1, Examples 1-3 of the present invention exhibited excellent removal rates for all four pollutants, demonstrating the universality and reliability of the carbon-based adsorbent material and preparation process for groundwater remediation prepared in this invention. Compared with Examples 1-3, Comparative Example 1 showed a decrease in the adsorption rate of all pollutants, highlighting the role of diatomaceous earth in constructing a stable porous framework. Comparative Example 2 showed a sharp decrease in the removal rates of Cr(VI) and TC, indicating the role of magnetic functional fillers in the reduction of Cr(VI) and catalytic degradation of TC. Comparative Example 3 showed a significant decrease in the removal efficiency of TC, thus clarifying the role of ZIF-90 in selectively adsorbing and enriching target pollutants.

[0086] Figure 1 The results showed that after 6 cycles, the carbon-based adsorbent material prepared in this invention for groundwater remediation achieved removal rates of 82.1% for Pb(II) and 88.9% for tetracycline, indicating that the Pb(II) prepared in this invention maintains relatively stable adsorption and catalytic performance, which is of great significance in the practical application of treating complex pollution in wastewater. Figure 2 As shown, the magnetic functional filler exhibits a uniform particle morphology with a relatively concentrated particle size distribution, no obvious agglomeration, and good dispersibility. The figure shows a regular polyhedral morphology, indicating that the ZIF-90 shell has been successfully grown and formed a regular crystal structure. The particle surface is dense and has a slight porous texture, while the core region is dense, indicating that the magnetic functional filler has successfully prepared a core-shell structure.

[0087] In summary, this invention uses diatomaceous earth and agricultural and forestry waste as matrix raw materials, and constructs a synergistic system through a one-step confined carbonization method and precise coupling with magnetic functional fillers. The natural porous framework of diatomaceous earth provides structural stability for the material, the active sites formed after the carbonization of agricultural and forestry waste strengthen the adsorption basis, and the magnetic functional fillers endow the material with magnetic responsiveness, catalytic degradation ability, and selective adsorption characteristics. Through interfacial chemical bonding and functional complementarity, the components achieve highly efficient synergistic removal of heavy metals and antibiotics from groundwater. This not only solves the defects of traditional adsorption materials such as single function and easy aggregation, but also breaks through the technical bottleneck of complex pollution remediation, and has the advantages of environmental adaptability, recyclability, and green economy.

[0088] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A carbon-based adsorbent material for groundwater remediation, characterized in that, The raw materials include the following parts by weight: 80-100 parts modified carbon material matrix, 5-20 parts magnetic functional filler; The modified carbon material matrix comprises the following raw materials in the following mass ratio: diatomaceous earth: agricultural and forestry waste = 1:3-8; The method for preparing the modified carbon material matrix includes the following steps: (1) Diatomite and agricultural and forestry waste are pretreated to form pretreated diatomite and agricultural and forestry waste; (2) Take the pretreated diatomaceous earth and agricultural and forestry waste, ball mill and mix them to obtain mixed powder, add the mixed powder to deionized water, and ultrasonically disperse it to form a modified carbon material matrix; The magnetic functional filler comprises raw materials in the following mass ratio: Fe(NO3)3·9H2O:Cu(NO3)2·3H2O:2-imidazolium formaldehyde:Zn(NO3)2·6H2O=8-10:2.5:7:15; The method for preparing the magnetic functional filler includes the following preparation steps: (a) Fe(NO3)3·9H2O, Cu(NO3)2·3H2O and sodium citrate were added to ethylene glycol in sequence and stirred magnetically. Then urea was added and stirred until dissolved. A solvothermal reaction was carried out. After cooling, a black precipitate was obtained. The black precipitate was washed, dried, calcined, ground and sieved to form CuFe2O4 powder. (b) Take anhydrous methanol and divide it into three portions. Disperse CuFe2O4 powder in the first portion of anhydrous methanol, sonicate it, add polyethyleneimine solution dropwise to form a mixed system, stir the mixed system at a constant temperature, centrifuge, collect the solid, wash and dry it to obtain modified CuFe2O4. (c) The modified CuFe2O4 was redispersed in the second part of anhydrous methanol, 2-imidazolium formaldehyde was added, and the mixture was stirred to form a mixture. Zn(NO3)2·6H2O was weighed and dissolved in the third part of anhydrous methanol to form a zinc nitrate methanol solution. The zinc nitrate methanol solution was added dropwise to the mixture and stirred continuously to form an emulsion. (d) Centrifuge the emulsion, collect the precipitate, wash it, and vacuum dry it to obtain the magnetic functional filler; The preparation method of the carbon-based adsorbent material for groundwater remediation specifically includes the following steps: S1, magnetic functional fillers are added to the modified carbon material matrix, ultrasonically treated, and mechanically stirred to form a paste-like mixture; S2, press the paste mixture into shape, dry it, and form a molded embryo; S3. The molded preform is carbonized and then cooled to room temperature to obtain the carbonized product. After being removed, it is crushed, sieved, washed, and dried to obtain a carbon-based adsorbent material for groundwater remediation.

2. The carbon-based adsorbent material for groundwater remediation according to claim 1, characterized in that, The agricultural and forestry waste is one or more of the following: corn cobs, rice husks, wheat straw, and peanut shells; In step (2), the ratio of diatomaceous earth to deionized water is 1 g: 10-30 mL.

3. The carbon-based adsorbent material for groundwater remediation according to claim 1, characterized in that, In step (a), the ratio of sodium citrate, urea, Fe(NO3)3·9H2O and ethylene glycol is 1g:6g:8-10g:80mL; In step (b), the ratio of CuFe2O4 powder, the first portion of anhydrous methanol, and the polyethyleneimine solution is 1g:25mL:2mL. In step (c), the ratio of the modified CuFe2O4 to the second part of anhydrous methanol is 1g:50-75mL, and the ratio of the Zn(NO3)2·6H2O to the third part of anhydrous methanol is 3g:10mL.

4. A method for preparing a carbon-based adsorbent material for groundwater remediation according to any one of claims 1-3, characterized in that, Specifically, the following steps are included: S1, magnetic functional fillers are added to the modified carbon material matrix, ultrasonically treated, and mechanically stirred to form a paste-like mixture; S2, press the paste mixture into shape, dry it, and form a molded embryo; S3. The molded preform is carbonized and then cooled to room temperature to obtain the carbonized product. After being removed, it is crushed, sieved, washed, and dried to obtain a carbon-based adsorbent material for groundwater remediation.

5. The method for preparing a carbon-based adsorbent material for groundwater remediation according to claim 4, characterized in that, In step S3, the carbonization is carried out under a nitrogen atmosphere by heating from room temperature to 600 ℃ at a heating rate of 5 ℃ / min, and holding at that temperature for 2 h.

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