Preparation method of hyperelastic pyrrole-doped graphene sponge and application of hyperelastic pyrrole-doped graphene sponge in efficiently blocking and controlling atrazine in soil and recycling

Abstract

The invention discloses a preparation method of hyperelastic pyrrole-doped graphene sponge and application of the hyperelastic pyrrole-doped graphene sponge in efficiently blocking and controlling atrazine in soil and recycling, and relates to the technical field of soil pollution remediation. The method comprises the following steps: dropwise adding pyrrole into a graphene oxide aqueous solution, uniformly mixing, and carrying out ultrasonic treatment; after ultrasonic treatment is finished, putting into a reaction kettle, heating to 100-220 DEG C, and carrying out hydrothermal reaction for 2-24 hours; after the reaction is finished, taking out and cleaning to obtain pyrrole-doped graphene hydrogel; and soaking the pyrrole-doped graphene hydrogel in an ethanol solution, standing, taking out, and freeze-drying to obtain the hyperelastic pyrrole-doped graphene sponge. The invention can obtain the preparation method of the hyperelastic pyrrole-doped graphene sponge and the application of the hyperelastic pyrrole-doped graphene sponge in efficiently blocking and controlling atrazine in soil and realizing recovery.

Description

Technical Field

[0001] This invention relates to the field of soil pollution remediation technology, specifically to a method for preparing a superelastic pyrrole-doped graphene sponge and its application in efficiently controlling atrazine in soil and achieving its recovery. Background Technology

[0002] The three northeastern provinces of my country are representative of black soil farming globally and serve as a "ballast stone" for ensuring national food security. Corn is a major grain crop in Northeast China and plays a vital role in China's agricultural production. Today, pesticides have become a key production resource for ensuring the grain supply of this "black soil granary." Among them, the chlorpyrifos-based herbicide atrazine (AT), chemically known as 2-chloro-4-ethylamine-6-isopropylamine-1,3,5-triazine, is used particularly extensively in corn cultivation.

[0004] Furthermore, the abundant organic matter (OM) in black soil allows for rapid adsorption of AT upon entering the soil, forming residues. However, the widespread freeze-thaw cycles in mid- to high-latitude regions cause soil aggregates to break down and reorganize, leading to the leaching of low-molecular-weight hydrophilic components (such as short-chain aliphatic carboxylic acids, hydrocarbons, and amino acids), affecting soil properties and altering the residual state of pollutants. In addition, the turnover of soil aggregates changes the distribution of soil particles and the partition coefficients between soil colloids, water, and pollutants, potentially affecting the exposure of soil active sites and exacerbating pollutant migration. Fortunately, multiple studies have shown that carbon-based materials with aromatic carbon, phenolic structures, and conjugated double bonds can interact strongly with the soil matrix, exhibiting high affinity for soil and enhancing the stability of soil aggregates. This provides a potential avenue for the adsorption and fixation of migrating pollutants during freeze-thaw cycles. AT residues in permafrost seriously threaten water security in agricultural areas, making the development of efficient AT removal methods essential.

[0005] Currently, various technologies are used to remove AT residues, such as advanced oxidation, biodegradation, and photocatalytic degradation. In contrast, adsorption methods have gained increasing attention due to their low cost, environmental friendliness, and wide applicability. Carbonaceous materials such as biochar (BC) and activated carbon (AC) are the most common adsorbents. However, conventional biochar exhibits poor structural stability during freeze-thaw cycles, making it difficult to recover and posing a risk of pollutant release. In recent years, graphene materials have received widespread attention in the environmental field due to their high specific surface area, excellent electrical conductivity, and good mechanical strength, enabling them to effectively adsorb and immobilize pollutants in soil. Addressing the issues of graphene's easy dispersion and difficulty in recovery in environmental applications, the more popular graphene aerogel has emerged. However, aerogels are prone to aggregation and exhibit poor stability during freeze-thaw cycles.

[0006] Therefore, there is an urgent need to find a simple preparation method that can solve the problems of easy dispersion and difficult recovery of graphene as well as the poor stability of graphene aerogel, and then apply it to the controlled adsorption of migrating atrazine during the freeze-thaw cycle of black soil. Summary of the Invention

[0007] The purpose of this invention is to solve the above-mentioned technical problems by providing a method for preparing a superelastic pyrrole-doped graphene sponge and its application in efficiently controlling atrazine in soil and realizing its recycling.

[0008] A method for preparing a superelastic pyrrole-doped graphene sponge, comprising the following steps:

[0009] Step S1: Synthesis of pyrrole-doped graphene hydrogel:

[0010] Pyrrole was added dropwise to an aqueous solution of graphene oxide, mixed thoroughly, and then sonicated. After sonication, the mixture was placed in a reaction vessel, heated to 100-220°C, and subjected to hydrothermal reaction at 100-220°C for 2-24 hours. After the reaction was completed, the mixture was removed and washed to obtain pyrrole-doped graphene hydrogel.

[0011] The amount of pyrrole added is 1-10% of the volume fraction of the pyrrole-doped graphene hydrogel;

[0012] Step S2: Preparation of superelastic pyrrole-doped graphene sponge:

[0013] The pyrrole-doped graphene hydrogel obtained in step S1 was immersed in an ethanol solution, allowed to stand, and then freeze-dried for 12-48 h to obtain a superelastic pyrrole-doped graphene sponge.

[0014] An application of a superelastic pyrrole-doped graphene sponge, wherein the superelastic pyrrole-doped graphene sponge is used to efficiently control the migration of atrazine during the freeze-thaw cycle of black soil and to achieve its recovery.

[0015] The beneficial effects of this invention are:

[0016] (1) This invention prepares a superelastic graphene sponge rGO by effectively controlling the concentration of graphene oxide precursor, the proportion of doped pyrrole N and the proportion of ethanol solution. N2.0First, hydrothermal in-situ self-assembly can prepare graphene oxide sponges (rGO) with relatively complete conjugated structures on their surfaces. Furthermore, by controlling the reaction temperature and time, the number of oxygen-containing functional groups on the material surface can be modulated, thereby affecting surface interactions and interfering with the material's self-assembly behavior. In addition, the partial restoration of the conjugated structures between graphene sheets triggers π-π stacking effects and van der Waals forces, promoting the self-assembly of rGO sheets and ensuring the stability of its layered structure. The presence of these forces results in relatively small interlayer spaces in rGO, a characteristic that significantly impacts its physicochemical properties. The re-stacked graphene oxide sheets cover the reaction sites on the graphene sheets, restricting the diffusion and transport of external water molecules between layers, leading to low adsorption efficiency, which also hinders environmental applications based on adsorption behavior. Notably, graphene oxide exhibits a skin effect during self-assembly, which causes numerous wrinkles to form on the surface of the graphene hydrogel. The presence of these wrinkles is detrimental to maintaining good mechanical properties after the material dries. It easily causes the graphene oxide film to bend under the influence of the confined surface tension of the water inside, forming film misalignments and creating structural defects, directly reducing the mechanical properties of the sponge. Controlling the internal space and surface capillary tension of the graphene hydrogel using ethanol is crucial for achieving high-performance material preparation and overcoming obstacles in environmental applications.

[0017] (2) This invention provides an organic pollutant remediation agent, rGO, that can be applied to both water bodies and soil freeze-thaw cycles. N2.0 The highest adsorption capacity of AT in the aqueous phase reached 1210.16 mg / g. Adsorption kinetic studies showed that rGO N2.0 The adsorption process of rGO conforms to a first-order kinetic model, indicating that its adsorption is mainly physical adsorption, relying primarily on π-π interactions and hydrophobic effects. N2.0 It exhibits good stability over a wide pH range (2-11) and under various ion competition conditions, maintaining 90% adsorption capacity and 86.62% recovery rate after 5 cycles, demonstrating highly stable surface properties. In soil freeze-thaw cycle experiments, rGO... N2.0 It can effectively control the migration of AT in soil, significantly reducing the AT concentration in the leachate, and no residual amount was detected after four freeze-thaw cycles. Furthermore, due to the extremely strong mechanical and elastic properties of graphene sponges, rGO… N2.0 The fact that it can maintain high resistance performance and recovery rate even after multiple freeze-thaw cycles indicates that it has good economic and sustainability performance in actual environmental remediation.

[0018] (3) This invention regulates the interlayer distance of in-situ self-assembled graphene hydrogel by pyrrole N, and prepares superelastic graphene sponge by regulating the proportion of confined water inside the hydrogel by different proportions of ethanol-water solution. In addition, the regulation mechanism and the resistance and control performance of atrazine during the freeze-thaw cycle of black soil are explored, and the relevant mechanism of action is analyzed.

[0019] This invention provides a method for preparing a superelastic pyrrole-doped graphene sponge and its application in efficiently controlling atrazine in soil and achieving its recycling. Attached Figure Description

[0020] Figure 1 This shows a scanning electron microscope image of the superelastic pyrrole-doped graphene sponge prepared in Example 2;

[0021] Figure 2 This shows a scanning electron microscope image of the superelastic pyrrole-doped graphene sponge prepared in Example 4;

[0022] Figure 3 The image shows a comparison between the superelastic pyrrole-doped graphene sponge with 2% pyrrole solution and the blank control.

[0023] Figure 4 This shows a scanning electron microscope image of the superelastic pyrrole-doped graphene sponge prepared in Example 3;

[0024] Figure 5 This shows a transmission electron microscope (TEM) image of the superelastic pyrrole-doped graphene sponge prepared in Example 2.

[0025] Figure 6 This shows a transmission electron microscope (TEM) image of the superelastic pyrrole-doped graphene sponge prepared in Example 4.

[0026] Figure 7 This shows a transmission electron microscope (TEM) image of the superelastic pyrrole-doped graphene sponge prepared in Example 3.

[0027] Figure 8 The images show electron diffraction patterns of the superelastic pyrrole-doped graphene sponges prepared in Examples 2-4.

[0028] Figure 9 The compression strain curve of the superelastic pyrrole-doped graphene sponge prepared in Example 4 is shown.

[0029] Figure 10 This shows the force-displacement curve of the superelastic pyrrole-doped graphene sponge prepared in Example 4;

[0030] Figure 11 This illustrates the adsorption kinetics of the superelastic pyrrole-doped graphene sponges prepared in Examples 1 and 4, with ● representing rGO. N2.0▲ represents rGO, 1 represents the first-order dynamic model fitting AT, and 2 represents the second-order dynamic model fitting AT.

[0031] Figure 12 The adsorption isotherms of the superelastic pyrrole-doped graphene sponge prepared in Example 4 are shown. ● represents 15℃, ▲ represents 25℃, ■ represents 35℃, 1 represents Langmuir model fitting, and 2 represents Freundlich simulation fitting.

[0032] Figure 13 This indicates the adsorption capacity of the superelastic pyrrole-doped graphene sponges prepared in Examples 1 and 4 for AT in different pH ranges. ;

[0033] Figure 14 The adsorption capacity of the superelastic pyrrole-doped graphene sponge prepared in Examples 1 and 4 for AT under different ionic backgrounds is indicated.

[0034] Figure 15 This demonstrates the regeneration capability of the superelastic pyrrole-doped graphene sponge prepared in Examples 1 and 4 in the aqueous phase.

[0035] Figure 16 This demonstrates the effect of different dosages of the superelastic pyrrole-doped graphene sponge prepared in Example 4 on the AT resistance control of the soil freeze-thaw cycle process;

[0036] Figure 17 This indicates the AT resistance and recovery rate of the superelastic pyrrole-doped graphene sponge prepared in Example 4 during the freeze-thaw cycle, under the same number of cycles. Detailed Implementation

[0037] Specific Implementation Method 1: This implementation method describes a method for preparing a superelastic pyrrole-doped graphene sponge, which is carried out according to the following steps:

[0038] Step S1: Synthesis of pyrrole-doped graphene hydrogel:

[0039] Pyrrole was added dropwise to an aqueous solution of graphene oxide, mixed thoroughly, and then sonicated. After sonication, the mixture was placed in a reaction vessel, heated to 100-220°C, and subjected to hydrothermal reaction at 100-220°C for 2-24 hours. After the reaction was completed, the mixture was removed and washed to obtain pyrrole-doped graphene hydrogel.

[0040] The amount of pyrrole added is 1-10% of the volume fraction of the pyrrole-doped graphene hydrogel;

[0041] Step S2: Preparation of superelastic pyrrole-doped graphene sponge:

[0042] The pyrrole-doped graphene hydrogel obtained in step S1 was immersed in an ethanol solution, allowed to stand, and then freeze-dried for 12-48 h to obtain a superelastic pyrrole-doped graphene sponge.

[0043] Specific Implementation Method Two: The difference between this implementation method and Specific Implementation Method One is that the ratio of the volume of pyrrole to the mass of graphene oxide in the graphene oxide aqueous solution in step S1 is (0.01~0.5) mL: (5~50) mg.

[0044] The other steps are the same as in Specific Implementation Method 1.

[0045] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the graphene oxide aqueous solution mentioned in step S1 is prepared according to the following steps:

[0046] Graphene oxide was added to deionized water and sonicated for 10-60 min to obtain an aqueous solution of graphene oxide. The ratio of the mass of graphene oxide to the volume of deionized water in the aqueous solution of graphene oxide was (5-50) mg: 10 mL.

[0047] The other steps are the same as in Specific Implementation Method 1 or 2.

[0048] Specific Implementation Method Four: The difference between this implementation method and Specific Implementation Methods One to Three is that the ultrasound time in step S1 is 5 to 60 minutes.

[0049] The other steps are the same as those in Specific Implementation Methods One to Three.

[0050] Specific Implementation Method 5: The difference between this implementation method and Specific Implementation Methods 1 to 4 is that after the reaction is completed in step S1, the sample is taken out and cleaned with deionized water.

[0051] The other steps are the same as those in Specific Implementation Methods One through Four.

[0052] Specific Implementation Method Six: The difference between this implementation method and Specific Implementation Methods One to Five is that the concentration of the ethanol solution mentioned in step S2 is 1~100%.

[0053] The other steps are the same as those in Specific Implementation Methods 1 to 5.

[0054] Specific Implementation Method Seven: The difference between this implementation method and Specific Implementation Methods One to Six is ​​that the settling time in step S2 is 20 min to 24 h.

[0055] The other steps are the same as those in Specific Implementation Methods 1 to 6.

[0056] Specific Implementation Method Eight: The difference between this implementation method and Specific Implementation Methods One to Seven is that in step S2, the ethanol solution is replaced every 20 to 40 minutes during the standing process.

[0057] The other steps are the same as those in Specific Implementation Methods 1 to 7.

[0058] Specific Implementation Method Nine: The difference between this implementation method and Specific Implementation Methods One to Eight is that: in step S2, a freeze dryer is used for freeze drying, and the freeze drying conditions are: temperature of -30.5~-24.4℃ and pressure of 100~4000 Pa.

[0059] The other steps are the same as those in Specific Implementation Methods 1 to 8.

[0060] Specific Implementation Method 10: This implementation method describes the application of a superelastic pyrrole-doped graphene sponge, which is used to efficiently control the migration of atrazine during the freeze-thaw cycle of black soil and achieve its recovery.

[0061] The beneficial effects of the present invention are verified using the following embodiments:

[0062] Example 1: A method for preparing a superelastic pyrrole-doped graphene sponge, comprising the following steps:

[0063] Step S1: Synthesis of pyrrole-doped graphene hydrogel:

[0064] The graphene oxide prepared using the modified Hammer method was freeze-dried to obtain graphene oxide (GO) powder. The graphene oxide powder was added to deionized water to prepare a 20 mg / mL GO solution. After sonication for 30 min, the solution was uniformly dispersed to obtain an aqueous solution of graphene oxide, which was stored at low temperature for later use.

[0065] A certain amount of graphene oxide aqueous solution was measured with a pipette and prepared into a 2 mg / mL precursor solution. The solution was placed in a 20 mL reaction liner and sonicated for 30 min to disperse it evenly. The solution was then placed in a reaction vessel, heated to 180 °C, and subjected to hydrothermal reaction at 180 °C for 12 h. After the reaction was completed, the solution was removed and washed with deionized water to obtain pyrrole-doped graphene hydrogel.

[0066] Step S2: Preparation of superelastic pyrrole-doped graphene sponge:

[0067] The pyrrole-doped graphene hydrogel obtained in step S1 was immersed in a 20% ethanol solution and allowed to stand for 24 h to displace the confined water inside the hydrogel. It is important to note that the ethanol solution needs to be replaced every 20 to 40 minutes until the background color is clear and transparent. After removal, it was freeze-dried for 48 h using a freeze dryer. The freeze-drying conditions were: temperature -30.5 to -24.4℃ and pressure 4000 Pa, to obtain a superelastic pyrrole-doped graphene sponge.

[0068] Example 2: In this example, 1% of the total reaction volume of pyrrole solution was added to each treatment group. All other experimental conditions were the same as in Example 1.

[0069] Example 3: In this example, 5% of the total reaction volume of pyrrole solution was added to each treatment group. All other experimental conditions were the same as in Example 1.

[0070] Example 4: In this example, 2% of the total reaction volume of pyrrole solution was added to each treatment group. All other experimental conditions were the same as in Example 1.

[0071] The pyrrole-doped graphene hydrogels in Examples 1-4 were characterized using scanning electron microscopy and transmission electron microscopy. The aqueous phase stability and adsorption performance of the superelastic pyrrole-doped graphene sponge in Example 4 were evaluated. Furthermore, its atrazine resistance during the freeze-thaw cycle of black soil was investigated. Specific results are as follows:

[0072] 1. Characterization results of Examples 1-4:

[0073] Figure 1 This shows a scanning electron microscope image of the superelastic pyrrole-doped graphene sponge prepared in Example 2. Figure 2 This shows a scanning electron microscope image of the superelastic pyrrole-doped graphene sponge prepared in Example 4. Figure 3 This image shows a comparison between the superelastic pyrrole-doped graphene sponge with 2% pyrrole solution and the blank control. Figure 4 This shows a scanning electron microscope image of the superelastic pyrrole-doped graphene sponge prepared in Example 3. Figure 3 The left side shows a superelastic pyrrole-doped graphene sponge with 2% pyrrole solution added, while the right side shows a sponge material with 0% pyrrole doping. Figure 5 This shows a transmission electron microscope (TEM) image of the superelastic pyrrole-doped graphene sponge prepared in Example 2. Figure 6 This shows a transmission electron microscope (TEM) image of the superelastic pyrrole-doped graphene sponge prepared in Example 4. Figure 7 This shows a transmission electron microscope (TEM) image of the superelastic pyrrole-doped graphene sponge prepared in Example 3. Figure 8 The image shows electron diffraction patterns of the superelastic pyrrole-doped graphene sponges prepared in Examples 2-4.

[0074] like Figure 1-4 As shown, adding an appropriate amount of pyrrole makes the rGO aerogel structure more porous and less dense than the original material, while excessive doping with pyrrole makes the internal structure of the aerogel denser. Figure 5-8 Transmission electron microscopy (TEM) images of graphene lattice revealed that the rGO aerogel with 2% pyrrole exhibited a relaxation phenomenon, with increased lattice spacing. Excessive pyrrole caused the aerogel lattice to become distorted and fragmented, with the lattice spacing decreasing from 0.459 nm to 0.437 nm. This indicates that N dopants can relax the graphene lattice, which to some extent affects the crystallinity of the material and is also beneficial for controlling lattice gaps, making it easier for surface electrons to transition.

[0075] Figure 9 This shows the compressive strain curve of the superelastic pyrrole-doped graphene sponge prepared in Example 4. Figure 10 The force-displacement curves of the superelastic pyrrole-doped graphene sponge prepared in Example 4 are shown. Figure 9-10 As shown, by controlling the hydrogen bonding forces between confined water inside the hydrogel and oxygen-containing functional groups on the graphene surface using ethanol solutions of different concentrations, the capillary contraction force on the graphene sheet surface was ultimately controlled, ensuring the integrity of the 3D structure of rGO. The dynamic process was captured using force-displacement curves and in-situ electron microscopy. Under full compression of up to 1000 times, rGO... N2.0 The fact that the morphological structure can be kept intact without being damaged proves that controlling the size of the hydrogen bonds inside rGO can guarantee excellent elastic properties.

[0076] 2. Adsorption kinetics:

[0077] The adsorption process is as follows: rGO and rGO N2.0 (0.05 g / L) was placed in 20 mg / L AT contaminant solution, with three replicates per treatment. The mixture was shaken at 200 rpm at a constant temperature. Samples were extracted at intervals, passed through a 0.22 µm membrane, sealed, and stored in the dark. Measurements were performed as described above. Furthermore, the obtained experimental data were fitted using pseudo-first-order kinetics, second-order kinetics, and intraparticle diffusion models to investigate the adsorption behavior and mechanism.

[0078] Figure 11 This illustrates the adsorption kinetics of the superelastic pyrrole-doped graphene sponges prepared in Examples 1 and 4, with ● representing rGO. N2.0 ▲ represents rGO, 1 represents the first-order dynamic model fitting AT, and 2 represents the second-order dynamic model fitting AT; for example Figure 11 As shown, rGO N2.0The adsorption of AT increased rapidly in the first 20 minutes, then the adsorption curve flattened out until adsorption equilibrium was reached after 1 hour. This indicates that a large number of adsorption sites are exposed on the material surface. N2.0 The large pore size of the pores allows pollutant molecules to be easily transported into the mass transfer channels, enabling rapid capture of pollutants in the aqueous phase. While rGO can also adsorb rapidly in the first 10 minutes and reach equilibrium at 40 minutes, the adsorption capacity at equilibrium is far lower than that of rGO. N2.0 This is mainly because the layered, three-dimensional structure of rGO leads to dense pores, reducing its mass transfer capacity and making it difficult for rGO to disperse in water quickly. Due to steric effects, the small pore size of rGO also prevents pollutant molecules from entering the mass transfer channels, resulting in a lower accumulation capacity and rapid reaching adsorption equilibrium at the outer surface. Furthermore, first-order kinetic models can better describe the properties of rGO. N2.0 The adsorption behavior of AT, its R 2 =0.9924, the first-order kinetics are mainly dominated by physical adsorption. The adsorption motive force mainly comes from the recovery of large π bonds and the introduction of pyrrole N during in-situ self-assembly, which modulates the magnitude of interlayer van der Waals forces, exposes more conjugated structures, and provides a favorable environment for the hydrophobic guest AT. The second-order kinetic model (R... 2 =0.9659) is more consistent with the adsorption behavior of rGO adsorbing AT, which is mainly chemical adsorption. This is mainly driven by the residual hydrogen bonds and carboxyl functional groups around the graphene sheets during the reduction process.

[0079] 3. Adsorption isotherm:

[0080] The adsorption process was carried out at different temperatures (15℃, 25℃, 35℃) for rGO and rGO. N2.0 Based on adsorption kinetic data, initial concentrations of 5 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, 50 mg / L, and 100 mg / L were set, with an adsorption equilibration time of 1 hour. Each treatment was performed in triplicate, with shaking at 200 rpm. Data were collected at regular intervals, and the membrane was passed through a 0.22 µm membrane for measurement, following the same method as above. Furthermore, to gain a deeper understanding of the adsorption and fixation process and mechanism of AT by the adsorbent, we fitted the adsorption isotherm data using the Langmuir model and the Freundlich model, respectively.

[0081] Figure 12 The adsorption isotherms of the superelastic pyrrole-doped graphene sponge prepared in Example 4 are shown below. ● represents 15℃, ▲ represents 25℃, ■ represents 35℃, 1 represents Langmuir model fitting, and 2 represents Freundlich simulation fitting. Figure 12As shown, with the increase of the initial AT concentration, rGO N2.0 The adsorption capacity of AT gradually increased, indicating that the N-modified material has sufficient reaction sites to capture and immobilize higher concentrations of pollutants. Furthermore, as the reaction system temperature increased, rGO... N2.0 The adsorption capacity of AT was significantly increased, indicating that the reaction is endothermic, and rGO N2.0 The favorable thermal effect of the material is one of the reasons for the increased adsorption capacity. In this study, the rGO calculated using the Langmuir isotherm model... N2.0 The maximum saturated adsorption capacity is 1210.16 mg / g. Furthermore, K... L The affinity index represents the relationship between pollutants and adsorbents. It gradually increases with increasing temperature. This is mainly because high temperatures make molecular motion more intense, strengthening π-π interactions. At the same time, increasing temperature can further strengthen the effect of hydrogen bonds, ultimately leading to an increase in the affinity index.

[0082] 4. Coexistence of pH and ions:

[0083] The experimental conditions were as follows: the initial concentration of AT was set at 20 mg / L, and the initial pH of the solution was adjusted to a range of 2-11 using 1 M HCl or NaOH. rGO and rGO... N2.0 The dosage was 0.05 g / L. In addition, four common anions found in soil were selected. The study investigated the addition of four anions and HA to an initial AT contaminated solution at a concentration of 20 mg / L, resulting in anion concentrations of 10 mM and HA concentrations of 5 mg / L. The dosage of each adsorbent was the same as described in the experimental protocol. After shaking at 200 rpm for 12 hours at room temperature, samples were collected, filtered through a membrane (0.22 pm), and stored.

[0084] Figure 13 This indicates the adsorption capacity of the superelastic pyrrole-doped graphene sponges prepared in Examples 1 and 4 for AT in different pH ranges. ; Figure 14 The values ​​represent the adsorption capacity of the superelastic pyrrole-doped graphene sponges prepared in Examples 1 and 4 for AT under different ionic backgrounds. For example... Figure 13 As shown, rGO N2.0 Both rGO and AT exhibit stable adsorption capacity over a wide pH range. Figure 14 This shows that even with competition from multiple anions and HA, the adsorption capacity for AT remains relatively stable. This is mainly due to the highly stable chemical structure resulting from the conjugated structure on the surface of graphene materials. N2.0The surface is mainly composed of carbon atoms and does not contain active functional groups that are easily affected by pH and other anions. Therefore, the chemical properties and surface charge distribution of graphene change little over a wide pH range and in complex media, thus making its adsorption capacity relatively stable.

[0085] 5. Repeated regeneration:

[0086] The experimental conditions are: rGO and rGO N2.0 (0.05 g / L) was added to a 20 mg / L AT contaminated solution. After adsorption for 2 hours, the sample was removed, washed three times with deionized water and three times with ethanol, and then dried in an oven at 60°C. The above steps were repeated five times for the next round of adsorption experiments. Samples were taken and the desorption efficiency of AT was calculated.

[0087] Figure 15 This indicates the recyclability of the superelastic pyrrole-doped graphene sponges prepared in Examples 1 and 4 in the aqueous phase; such as Figure 15 As shown, rGO N2.0 In the first five cycles, the adsorption capacity decreased only from 249.12 mg / kg to 232.85 mg / kg, which is quite considerable. Conversely, the adsorption capacity of rGO for AT decreased from 89.60 mg / kg to 25.34 mg / kg. This is mainly because the two materials have different adsorption mechanisms for pollutants. Due to its dense structure, rGO's internal sites are not fully exposed, and AT is only adsorbed and fixed through its edge oxygen-containing functional groups. During the regeneration process, the oxygen-containing functional groups on the rGO surface are lost, reducing its adsorption capacity. N2.0 Because pyrrole doping endows it with stable properties, it exhibits very high stability in aqueous phase reactions, which can lay a solid foundation for subsequent practical applications.

[0088] 6. This example demonstrates the control of atrazine migration during the freeze-thaw cycle of black soil:

[0089] The experimental conditions were as follows: After air-drying the collected soil samples, coarse soil clods and plant debris were filtered through a 4 mm nylon sieve. rGO was then... N2.0 The rGO was uniformly mixed into contaminated soil at proportions of 0.5%, 1%, 1.5%, 2%, 2.5%, and 3%, followed by 15 freeze-thaw cycles, with three replicates per group. The effectiveness of rGO in controlling the target pollutant was evaluated by measuring the AT concentration in the leachate, and the optimal rGO concentration was determined. N2.0 Dosage. Under optimal dosage and ideal freeze-thaw conditions, a total of 15 freeze-thaw cycles were performed. After each freeze-thaw cycle, the leachate was collected, stored in the dark, and prepared for analysis. Subsequently, based on the above rGO... N2.0Experimental data on AT migration control in soil during freeze-thaw cycles were used to determine the optimal number of freeze-thaw cycles for achieving the best control rate. Leachate was collected, stored in the dark, and prepared for testing. The material under these conditions was then recovered, dried, and subjected to cyclic control experiments under the same conditions, repeated five times. (Elastic sponge rGO) N2.0 The flotation method is used for recycling. Deionized water is injected into soil that has just completed a freeze-thaw cycle. Once the soil moisture content reaches 100%, the container is shaken, and rGO is collected. N2.0 It will float to the surface. rGO was washed with deionized water and ethanol respectively. N2.0 Three times, the samples were dried in an oven at 60°C, weighed, and then the next round of resistance control experiments was conducted.

[0090] Figure 16 This demonstrates the effect of different dosages of the superelastic pyrrole-doped graphene sponge prepared in Example 4 on the AT resistance control during the soil freeze-thaw cycle. Figure 17 This indicates the AT resistance and recovery rate of the superelastic pyrrole-doped graphene sponge prepared in Example 4 during freeze-thaw cycles, under the same number of cycles. For example... Figure 16 As shown, in the treatment group without any applied materials, the AT concentration in the leachate reached its maximum value of 14.94 mg / L after 7 freeze-thaw cycles, indicating that freeze-thaw cycles rapidly desorbed residual AT from the soil. Meanwhile, when rGO... N2.0 When the dosage was increased to 1.5%, the peak concentration of the leachate appeared after the 8th freeze-thaw cycle, reaching a maximum of only 5.65 mg / L. With the dosage further increased to 2%, after 4 freeze-thaw cycles, no residual AT was detected in the leachate, and after the 3rd freeze-thaw cycle, the AT content in the filtrate was 2.14 mg / L. When the dosage continued to increase to 2.5%, after the 3rd freeze-thaw cycle, the AT content in the filtrate was 1.95 mg / L, showing a relatively small decrease. This may be because the adsorption sites between pollutant molecules in the soil and water medium and the material reached equilibrium, and the introduction of more adsorption sites did not lead to an increase in adsorption.

[0091] Therefore, from an economic perspective, a 2% addition rate was chosen as the optimal input ratio for further experiments. Subsequently, the rGO after four freeze-thaw cycles was... N2.0 Using the flotation method, and selecting MeOH-NaCl as the regeneration solvent, we extracted rGO. N2.0 Five cycles of regeneration studies were conducted. After freeze-drying, the recovery rate was calculated, and a second repeat experiment was performed. The results are as follows: Figure 17 As shown, rGO N2.0 Within 5 cycles, it still maintains a resistance control rate of nearly 90% and a recovery rate of 86.62% for AT, mainly due to rGO. N2.0The surface active sites are very stable and will not be destroyed by changes in the external environment. The above results indicate that the superelastic pyrrole-doped graphene sponge prepared in this invention has good economic practicality.

Claims

1. A method of preparing a super-elastic pyrrole-doped graphene sponge, characterized by, The preparation method is carried out according to the following steps: Step S1, synthesizing pyrrole-doped graphene hydrogel: Pyrrole is added dropwise into the aqueous solution of graphene oxide, and after uniform mixing, ultrasonic treatment is performed; after the ultrasonic treatment is completed, the reaction kettle is placed in a heating device and heated to 100-220 DEG C, and the hydrothermal reaction is carried out at a temperature of 100-220 DEG C for 2-24 h; after the reaction is completed, the product is taken out and washed to obtain pyrrole-doped graphene hydrogel; The dropwise amount of pyrrole accounts for 1-10% of the volume fraction of the pyrrole-doped graphene hydrogel; Step S2, preparing super-elastic pyrrole-doped graphene sponge: The pyrrole-doped graphene hydrogel obtained in step S1 is soaked in an ethanol solution, and after standing, it is taken out and freeze-dried for 12-48 h to obtain a super-elastic pyrrole-doped graphene sponge.

2. The method for preparing a superelastic pyrrole-doped graphene sponge according to claim 1, characterized in that, The volume of pyrrole to the mass of graphene oxide in the aqueous solution of graphene oxide in step S1 is (0.01-0.5) mL:(5-50) mg.

3. The method for preparing a superelastic pyrrole-doped graphene sponge according to claim 1, characterized in that, The aqueous solution of graphene oxide in step S1 is prepared according to the following steps: Graphene oxide is added to deionized water, and after ultrasonic treatment for 10-60 min, an aqueous solution of graphene oxide is obtained; the mass of graphene oxide to the volume of deionized water in the aqueous solution of graphene oxide is (5-50) mg:10 mL.

4. The method for preparing a superelastic pyrrole-doped graphene sponge according to claim 1, characterized in that, The ultrasonic treatment time in step S1 is 5-60 min.

5. The method for preparing a superelastic pyrrole-doped graphene sponge according to claim 1, characterized in that, After the reaction in step S1 is completed, the product is taken out and washed with deionized water.

6. The method for preparing a superelastic pyrrole-doped graphene sponge according to claim 1, characterized in that, The concentration of the ethanol solution in step S2 is 1-100%.

7. The method for preparing a superelastic pyrrole-doped graphene sponge according to claim 1, characterized in that, The standing time in step S2 is 20 min-24 h.

8. The method for preparing a superelastic pyrrole-doped graphene sponge according to claim 1, characterized in that, During the standing process in step S2, the ethanol solution is replaced every 20-40 min.

9. The method for preparing a superelastic pyrrole-doped graphene sponge according to claim 1, characterized in that, In step S2, freeze-drying is performed using a freeze-drying machine, and the freeze-drying conditions are: temperature of-30.5 to-24.4 DEG C, and pressure of 100-4000 Pa.

10. Use of a super-elastic pyrrole-doped graphene sponge prepared according to the method of any one of claims 1 to 9, characterized in that, The super-elastic pyrrole-doped graphene sponge is used for efficiently controlling the migration and recovery of atrazine in black soil during freeze-thaw cycles.

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