Self-driven micromotor based on mxene, preparation method and application thereof

Abstract

The application discloses a self-driven micromotor based on MXene, a preparation method and application thereof, and belongs to the technical field of environmental remediation. The self-driven micromotor TMMF-betaCD takes MXene-derived TiO2 as a base skeleton, mechanically peels off the MXene-derived TiO2 / MnO2 composite material after in-situ growth of MnO2 on the skeleton, then modifies MnFe2O4 on the composite material by using an electrostatic adsorption method to endow the material with a magnetic recovery characteristic, and finally functionalizes and modifies beta-CD on the composite material by using a microwave heating method, so that the preparation is completed. When the TMMF-betaCD and hydrogen peroxide are jointly used on a soil hydrophobic pollutant (such as a polycyclic aromatic hydrocarbon), MnO2 catalyzes the decomposition of hydrogen peroxide to generate bubbles to push the TMMF-betaCD to move autonomously, greatly enhances mass transfer in the soil, realizes dynamic capture of the pollutants in the soil based on host-guest interaction between the beta-CD and the pollutant molecules, and finally achieves the effect of purifying the soil.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of environmental remediation, and particularly relates to a self-driven micro motor based on MXene, a preparation method and application thereof. BACKGROUND

[0002] The acceleration of industrialization and urbanization inevitably brings about corresponding environmental problems, among which soil pollution problems have become the focus of social concern. Polycyclic aromatic hydrocarbons (PAHs) are one of the most common pollutants in soil, which have strong hydrophobicity and low water solubility, making them difficult to be detected and removed in the environment. The main sources of PAHs are human emissions, including industrial wastewater, accidental oil spills, coal gasification and incomplete combustion or pyrolysis of organic fuels. PAHs can contaminate soil and surface water through deposition and rainfall scouring, and they are persistent, bioaccumulative and toxic, which can induce cancer, respiratory damage, skin and eye irritation, digestive damage, cardiovascular system diseases, immune system diseases, and affect reproduction and development, posing a great threat to the survival of humans and animals. Therefore, it is of great significance to remove PAHs from the environment.

[0003] At present, the commonly used methods for removing PAHs from contaminated soil mainly include chemical oxidation, soil washing, thermal desorption and bioremediation, etc. Among them, advanced oxidation processes (AOPs) are of great concern due to their high removal efficiency, but AOPs have several obvious shortcomings, such as high cost, harsh reaction conditions, and difficulty in catalyst recovery. Other methods, such as phytoremediation and microbial degradation, may face problems such as long time consumption, soil nutrient reduction and generation of harmful degradation products. Therefore, it is urgent to develop a simple and convenient method that can quickly produce results without causing secondary pollution.

[0004] In recent years, self-driven micro motors have been effectively applied in the fields of environmental cleaning and medical applications due to their unique characteristics of autonomous movement and high power output. Unlike the movement process of traditional micro / nanoparticles which relies on Brownian motion and passive diffusion, micro / nanomotors can move autonomously by utilizing the energy generated by external stimuli (light, ultrasound, electricity, magnetic field, etc.) or chemical reactions (reaction fuels are H2O2, glucose, urea, water, etc.). The self-driven movement of micro / nanomotors can make the surrounding fluid mix more strongly between the contaminated samples, thereby accelerating the degradation of pollutants. In particular, for micro / nanomotors that rely on bubble propulsion to achieve self-driving, the continuous generation of micro-bubbles can further enhance the mass transfer effect, and have the advantages of large driving force, good energy conversion efficiency and good controllability. Related studies have shown that bubble-driven micro motors can improve the transport efficiency in the underground environment and achieve effective in-situ soil purification. Therefore, designing suitable self-driven micro motors is expected to solve the related problems faced in the remediation of soil using traditional methods.

[0005] MXene is a kind of two-dimensional material with great potential for manufacturing micromotors, and its general formula is M n+1 X n T x (n=1,2,3), wherein M is a transition metal (Ti, Mo, V), X is carbon or nitrogen, T x is a surface termination functional group (-O, -F, -OH). MXenes have high electrical conductivity, excellent chemical stability, thermal conductivity, hydrophilicity, surface functionality and environmental compatibility. Therefore, MXenes show considerable application potential in many fields including water remediation.

[0006] Cyclodextrin (CD) is a starch hydrolysis product with a "inner hydrophobic and outer hydrophilic" cyclic molecular structure, and beta-CD is widely used because of its low production cost. The internal cavity of CD is highly hydrophobic and has strong affinity for hydrophobic guest molecules, so there is a host-guest interaction between the internal cavity of CD and the hydrophobic guest molecules, which can promote the encapsulation of the hydrophobic part of the guest molecules in the CD cavity to form a host-guest inclusion compound, thereby improving the solubility of the compound. Therefore, CD is often used in solid phase extraction experiments of PAHs, and CD is used as part of the fiber coating to selectively adsorb and enrich PAHs, so as to enhance the sensitivity and accuracy of detection and measurement.

[0007] However, there is no prior art of combining CD with micromotors / nanomotors for dynamic capture and removal of PAHs present in soil, and it is still unclear how to effectively functionalize and modify CD on the corresponding micromotors / nanomotors, and the corresponding preparation process and removal mechanism still need further exploration. SUMMARY

[0008] The purpose of the present application is to solve the problems existing in the prior art, and to provide a self-driven micromotor based on MXene and its preparation method. The micromotor material is obtained by functionalizing and modifying MnFe2O4 and beta-CD on MXene-derived TiO2 / MnO2 composite material. Benefiting from its autonomous movement and bubble generation, the TMMF-beta CD self-driven micromotor shows strong self-driving ability, greatly enhances the mass transfer in soil, and realizes the dynamic capture of PAHs in soil.

[0009] In order to achieve the above technical purpose, the present application is realized by the following technical scheme: the self-driven micromotor TMMF-beta CD based on MXene is a MXene-derived TiO2 / MnO2 composite material obtained by mechanically exfoliating MXene-derived TiO2 with MnO2 in situ, and the substrate skeleton is modified with magnetic MnFe2O4 and beta-CD. MXene-derived TiO2 is Ti3C2T xThe MXene is subjected to annealing treatment.

[0010] Further, the self-driven micromotor can utilize the bubbles generated by the catalytic decomposition of hydrogen peroxide to obtain driving force to enhance mass transfer.

[0011] Further, the self-driven micromotor has the characteristics of magnetically controlled directional motion and can be magnetically recycled.

[0012] The preparation method of the self-driven micromotor based on MXene is as follows:

[0013] 1) Ti3C2T is subjected to annealing treatment in a tube furnace. x The MXene is subjected to annealing treatment to obtain MXene-derived TiO2;

[0014] 2) After in-situ growth of MnO2 on the MXene-derived TiO2 by a hydrothermal method, the MXene-derived TiO2 / MnO2 composite material is obtained by mechanical exfoliation;

[0015] 3) MnFe2O4 is modified on the MXene-derived TiO2 / MnO2 composite material by electrostatic adsorption;

[0016] 4) β-CD is functionally modified on the composite material modified with MnFe2O4 by a microwave heating method to obtain a MXene-derived TiO2 / MnO2 / MnFe2O4-βCD self-driven micromotor, denoted as TMMF-βCD.

[0017] Further, in step 1), the heating rate is 5-12℃ / min -1 , and the heating reaction temperature is 500-600℃.

[0018] Further, the specific process of step 2) is as follows: the MXene-derived TiO2 is first dispersed in water, KMnO4 and MnSO4·H2O are added for heating reaction, the mass ratio of MXene-derived TiO2, KMnO4 and MnSO4·H2O is 1:5-10:0.8-1.4, the heating reaction temperature is 140-180℃, and the heating time is 10-24h; the obtained product is added into a tetrabutylammonium hydroxide solution, stirred and then dispersed in water, centrifuged, and the supernatant is collected to obtain the exfoliated MXene-derived TiO2 / MnO2 composite material.

[0019] Further, the specific process of step 4) is as follows: the MXene-derived TiO2 / MnO2 composite material modified with MnFe2O4 and β-CD-SH are weighed according to a mass ratio of 1.5-3:1, mixed in water added with dimethyl sulfoxide, subjected to microwave heating at 100-130℃ for 50-70min, centrifuged, and washed to obtain TMMF-βCD.

[0020] The above-mentioned self-driven micromotor based on MXene can be applied in the removal process of hydrophobic pollutants in soil. When used, 0.5wt%-2.0wt% of H2O2 solution and TMMF-βCD are added to the system, MnO2 catalyzes the decomposition of H2O2 to generate bubbles to push TMMF-βCD to move autonomously, and the mass transfer in the soil is enhanced. The pollutants are hydrophobic pollutant molecules, and the pollutant molecules can form inclusion compounds with the modified β-CD on the self-driven micromotor TMMF-βCD based on host-guest interaction to realize dynamic capture of pollutants. Finally, the separation rate of pollutants is realized based on the magnetic recovery characteristics of the micromotor, and the soil is purified.

[0021] The above-mentioned self-driven micromotor based on MXene can be used as an adsorption material to build a device for adsorbing hydrophobic pollutants in soil. Further, it is expected to build a complete industrial soil remediation system based on the device for environmental soil remediation.

[0022] The beneficial effects of the present application are:

[0023] 1. The present application obtains MXene-derived TiO2 / MnO2 composite material by hydrothermal method in-situ growth of MnO2 on MXene-derived TiO2 and then mechanical exfoliation, and uses it as a base skeleton. Then, MnFe2O4 is modified on the composite material by electrostatic adsorption method to make it have recyclable characteristics. Finally, the composite material is further functionalized and modified by β-CD-SH under microwave heating conditions to obtain the self-driven micromotor TMMF-βCD that the present application wants to protect.

[0024] 2. The self-driven micromotor TMMF-βCD disclosed in the present application is applied with hydrogen peroxide in actual application. The sprayed micro-nano bubbles can push the micromotor to move autonomously by catalyzing the decomposition of hydrogen peroxide by MnO2. The driving force obtained gives the material the ability to self-drive in the soil, greatly enhances the mass transfer in the soil, and is beneficial to increase the opportunity of collision and contact between the functional component β-CD of the micromotor and polycyclic aromatic hydrocarbons, thereby enhancing the host-guest interaction between them. β-CD inclusion polycyclic aromatic hydrocarbons to realize dynamic capture of polycyclic aromatic hydrocarbons in soil, and then the polycyclic aromatic hydrocarbon pollutants can be effectively adsorbed and removed from the soil, improving the adsorption efficiency of pollutants, and achieving the effect of purifying soil without external energy input.

[0025] 3. Since the self-driven micromotor TMMF-βCD disclosed in the present application has magnetism, it can realize separation, recovery, treatment and reuse after capturing pollutants in the soil through simple magnetic control operation, without causing secondary pollution, meeting the requirements of green environmental protection.

[0026] 4. The self-driven micro motor TMMF-βCD disclosed in the application is not only suitable for removing polycyclic aromatic hydrocarbons in soil, but also suitable for effectively removing other hydrophobic pollutants that can form inclusion compounds with the modified β-CD molecules on the micro motor through host-guest interaction, and has good universality;

[0027] 5. The self-driven micro motor TMMF-βCD disclosed in the application has the characteristics of green environmental protection and rich yield, and the preparation process is simple, without the use of expensive instrument materials, and has significant environmental and economic benefits, is suitable for batch preparation of environmental functional materials, and has good application prospect; in addition, the successful preparation and application of the material also provide a new solution for the removal of pollutants in the environment, and provide a new reference mechanism for the repair and purification of soil;

[0028] 6. The application first uses in-situ electrochemical impedance spectroscopy and relaxation time to monitor the dynamic process of removing polycyclic aromatic hydrocarbon pollutants from soil, and reveals the effective migration of the micro motor in the heterogeneous environment and the dynamic capture mechanism of the self-propelled micro motor for polycyclic aromatic hydrocarbons. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a preparation flow chart of the self-driven micro motor TMMF-βCD based on MXene disclosed in Example 1;

[0030] Figure 2 is a preparation process chart of the self-driven micro motor TMMF-βCD based on MXene disclosed in Example 1;

[0031] Figure 3 is a scanning electron microscope (SEM) image of MXene-derived TiO2 / MnO2(a) and TMMF-βCD(b) prepared in Example 1, and c, d are partial enlarged views of A, B parts in the b small graph;

[0032] Figure 4 is an X-ray energy dispersive (EDX) image of the self-driven micro motor TMMF-βCD prepared in Example 1;

[0033] Figure 5 is a motion time-lapse image of the self-driven micro motor TMMF-βCD prepared in Example 1;

[0034] Figure 6 is a graph of the relationship between the concentration of hydrogen peroxide and the motion speed of the self-driven micro motor TMMF-βCD;

[0035] Figure 7 is a mechanism diagram of the self-driven micro motor TMMF-βCD capturing polycyclic aromatic hydrocarbons in soil samples;

[0036] Figure 8Fig. a, b is the Nyquist plot of the self-propelled micromotor TMMF-βCD in removing PHE from soil; Fig. c is the image obtained by DRT analysis of the process of self-propelled micromotor TMMF-βCD in removing PHE from soil;

[0037] Figure 9 Fig. a, b is the absorbance change of PHE in soil when the self-propelled micromotor TMMF-βCD is used to purify soil in static and propulsion modes, wherein Fig. a, b is the UV contour map (a) and UV spectrum (b) of PHE in soil measured when TMMF-βCD micromotor is used to purify soil in static mode, Fig. c, d is the UV contour map (c) and UV spectrum (d) of PHE in soil measured when TMMF-βCD micromotor is used to purify soil in propulsion mode;

[0038] Figure 10 Fig. a is the UV contour map, and Fig. b is the UV spectrum for the quantitative test image of the self-propelled micromotor of unmodified β-CD adsorbing polycyclic aromatic hydrocarbons in soil. DETAILED DESCRIPTION

[0039] The following examples further illustrate the content of the present application, but should not be construed as limiting the present application. Modifications and replacements of the method, steps or conditions of the present application, without departing from the essence of the present application, all belong to the scope of the present application.

[0040] Example 1

[0041] In this example, a self-propelled micromotor TMMF-βCD based on MXene is obtained by layer-by-layer modification and functionalization on the MXene base material, and the preparation process is as shown in Figure 1-2 The specific preparation steps are as follows:

[0042] S101: 1.3 g of LiF is added to 20 mL of 9M HCl solution and stirred until completely dissolved, 0.5 g of Ti3AlC2 MAX phase powder is slowly added, stirred at 35℃ for 24 h, and washed with deionized water until pH ~ 6. The washed product is freeze-dried for 3 days to obtain Ti3C2T x MXene. The Ti3C2T x MXene is transferred to a tube furnace, heated to 550℃ at a heating rate of 10℃ min -1 , and cooled to room temperature and collected after 0 min to obtain MXene-derived TiO2 (multi-layer TiO2).

[0043] S102: 150 mg MXene-derived TiO2 was dispersed in 30 mL deionized water, 950 mg KMnO4 and 169 mg MnSO4·H2O were added, and stirred for 30 min. It was transferred into a high-pressure reaction kettle and reacted at 160°C for 12 h. The product was collected by centrifugation and washed with water and ethanol several times. After successfully growing MnO2 in situ on MXene-derived TiO2, 200 mg of the product was added to 8 mL of tetrabutylammonium hydroxide (TBAOH, 54%) solution, stirred for 2 h, and then dispersed in 45 mL of deionized water, shaken for 5 min, and centrifuged at 2000 rpm for 30 min (3-4 times). The supernatant was collected to obtain exfoliated MXene-derived TiO2 / MnO2.

[0044] S103: 0.752 g MnCl2·4H2O and 2 g FeCl3·6H2O were ultrasonically dissolved in 70 mL ethylene glycol, 5 g NaAc and 3 g polyethylene glycol were added, stirred for 1 h, and then transferred into a high-pressure reaction kettle and heated at 200°C for 10 h. The product was collected by centrifugation and washed with water and ethanol several times to obtain MnFe2O4.

[0045] A: 15 mg MnFe2O4 was added to a mixed solution of ultrapure water and ethanol (V / V, 1:1), and ultrasonicated for 30 s. B: 50 mg MXene-derived TiO2 / MnO2 was added to a mixed solution of ultrapure water and ethanol (V / V, 1:10), and A and B were mixed and stirred at room temperature for 1 h to modify the nanoparticles. Finally, magnetic collection was performed, and the nanoparticles were washed twice in ultrapure water and ethanol and dried overnight. MXene-derived TiO2 / MnO2 / MnFe2O4 self-driven micromotors (TM / MnFe2O4) with magnetism were obtained.

[0046] S104: 50 mg MXene-derived TiO2 / MnO2 / MnFe2O4 was mixed with 30 mg of thiol-β-cyclodextrin (β-CD-SH) in 25 mL deionized water and microwave-heated at 110°C for 60 min. When β-CD-SH was used, 250 μL of dimethyl sulfoxide (DMF) was added to the deionized water to improve its solubility. The product was collected by centrifugation and washed with water and ethanol several times to obtain the final product MXene-derived TiO2 / MnO2 / MnFe2O4-βCD self-driven micromotors (denoted as TMMF-βCD).

[0047] Related performance tests

[0048] 1. MXene-derived TiO2 / MnO2 and TMMF-βCD prepared in this example were subjected to scanning electron microscope (SEM) test, and the results are shown in Figure 3 Figure 3 ​As can be seen in the middle panel a, MnO2 nanosheets are in situ grown on MXene-derived TiO2. Figure 3 In panels bd, MnFe2O4 nanoparticles can be observed bound to the surface of the MXene-derived TiO2 / MnO2 composite material.

[0049] 2. The TMMF-βCD prepared in this example was subjected to X-ray energy dispersive spectroscopy (EDX) analysis. Figure 4 The results shown in the figure show that Ti, Mn, O, S, Fe, and C are uniformly distributed on TMMF-βCD, which proves that the self-propelled micromotor based on MXene was successfully prepared.

[0050] 3. In order to study the movement of the self-propelled micromotor TMMF-βCD in a solution containing 2.0wt% hydrogen peroxide and 0.5wt% sodium dodecyl sulfate (SDS) (the addition of SDS for testing here is based on the fact that the high HLB value (Hydrophilic Lipophilic Balance) of SDS means that it has good hydrophilicity, which can reduce the interfacial free energy of the micromotor and is conducive to the generation and injection of bubbles; the addition of SDS makes the bubbles generated by the micromotor denser and less likely to break, thereby making the movement process more coherent. Therefore, when shooting the motor movement video, adding SDS can better observe the motor movement and improve the video quality. However, it is not necessary to add SDS for actual soil purification. When performing soil purification, only TMMF-βCD and a certain concentration of hydrogen peroxide need to be added to the contaminated sample). -1 A mixed solution of 2.0 wt% hydrogen peroxide and 0.5 wt% SDS was dropped onto a glass slide. Images were taken using an optical microscope equipped with an OLYMPUS cellSensDimension system. See [Image file name] for time-lapse images of motion. Figure 5 As can be seen from the figure, due to the presence of MnO2, H2O2 is continuously catalyzed to decompose and produce O2 bubbles, and the abundant bubbles are ejected from the micromotor, which will continuously push the micromotor to move rapidly.

[0051] 4. Based on the previous test, the effect of different concentrations of hydrogen peroxide on the movement speed of TMMF-βCD was further studied. -1 , relative to soil mass), mixed solutions of different concentrations of hydrogen peroxide (0.5wt%, 1.0wt%, 1.5wt%, and 2.0wt%), and 0.5wt% SDS were dropped onto glass slides. The movement speed of the micromotor was captured and analyzed using an optical microscope equipped with an OLYMPUS cellSensDimension system. The results are shown in the table below. Figure 6As can be seen from the figure, the movement speed of the micromotor is positively correlated with the fuel (hydrogen peroxide) concentration. Therefore, the movement speed of TMMF-βCD can be controlled by adjusting the hydrogen peroxide concentration. In addition, the MXene-based self-propelled micromotor disclosed in this application can achieve high-speed movement at low fuel concentrations. The results in the figure show that when the hydrogen peroxide concentration increases from 0.5wt% to 2.0wt%, the average speed of the micromotor increases from 39.42μm s -1 significantly increased to 116.91 μm s -1 .

[0052] 5. To investigate the capture mechanism of polycyclic aromatic hydrocarbons (PAHs) in soil by TMMF-βCD, simulation experiments were conducted using phenanthrene (PHE), a representative PAH widely found in soil, as a model pollutant to reveal the capture mechanism of the pollutants in soil.

[0053] like Figure 7 As shown, the self-propelled micromotor generates local convection and mixing, enhancing the diffusion and mass transfer processes. Due to the self-propulsion characteristics of the micromotor, the contact probability between the functional structure β-CD in the micromotor and the pollutant PHE in the soil increases. Subsequently, when the micromotor collides with the PHE, the PHE molecules tend to separate from the soil due to the repulsion of the polar environment and the attraction of the non-polar β-CD cavity. This is the driving force for extracting the PHE molecules from the soil and forming the inclusion complex to be tested. Finally, because the surface of the micromotor is modified with magnetic MnFe2O4, the self-propelled micromotor that has completed the PHE collection work in the soil can be collected by magnetic attraction for subsequent testing. In this way, the MXene-based self-propelled micromotor can capture sufficient pollutants for direct monitoring without the need for complex pretreatment.

[0054] 6. To investigate the process of PHE capture in soil by MXene-based self-propelled micromotors, we used in situ EIS to characterize the kinetic behavior of PHE removal from soil using TMMF-βCD.

[0055] like Figure 8 As shown, the Nyquist plot of TMMF-βCD ( Figure 8 The R (insets a and b) show an upward trend, demonstrating the continuous removal of PHE molecules. In situ EIS measurements reveal the kinetic behavior of the system, while the DRT method provides more information about the complex electrochemical process. In the region of 0.01s < τ < 1s, a large change in dynamic resistance is observed, which is attributed to the cumulative effect of PHE molecules. ctsignificantly increased with the increase of reaction depth, which reflected the kinetic delay due to the continuous adsorption and encapsulation of PHE molecules on the surface of TMMF-βCD. The above kinetic analysis verified that TMMF-βCD could effectively migrate in soil due to its high self-propulsion, and also verified that the self-propelled micro-motor could dynamically capture PHE in soil.

[0056] 7. In order to quantitatively study the removal rate of TMMF-βCD to PHE in soil, the concentration of PHE in soil at different treatment times was quantitatively analyzed by ultraviolet-visible spectrophotometer.

[0057] The collected soil was first screened with a sieve with a pore size of 125 μm. Then, PHE was dispersed in acetonitrile to prepare a stock solution, and the soil was contaminated. The formed suspension was completely mixed on a rotary vibrating screen, and then the acetonitrile was evaporated under a fume hood for 2 days. The contaminated soil sample was aged in a fume hood for two months before use. When the purification test was carried out, the contaminated soil was pretreated, i.e. the contaminated soil was mixed with deionized water to form a slurry (water-soil mass ratio of 2:1), and then TMMF-βCD (10 g kg -1 , relative to the mass of soil) and H2O2 were used to study the adsorption performance, which was quantitatively determined by ultraviolet-visible spectrometer.

[0058] The results are shown in Figure 9 , Figure 9 show the concentration of PHE in soil when the self-driven micro-motor TMMF-βCD was used for decontamination in static and propulsion modes (TMMF-βCD (10 g kg -1 , relative to the mass of soil) and 2.0 wt% hydrogen peroxide were added to the contaminated soil in the propulsion group (treatment group), and only TMMF-βCD (10 g kg -1 , relative to the mass of soil) was added in the static group without hydrogen peroxide). In the same time interval, compared with the static mode (a, b subgraphs in Figure 9 ), the maximum absorption wavelength (λ max = 251) of PHE showed a very significant intensity change after treatment in the propulsion mode (c, d subgraphs in Figure 9 ). In the propulsion mode, the absorbance of PHE decreased sharply, indicating that PHE was successfully removed from the soil. The obvious difference between the static group and the propulsion group indicates that the self-driving of the micro-motor can improve the PHE capture efficiency when treating the soil sample, because the movement of the self-driven micro-motor enhances its contact with PHE.

[0059] In addition, in order to verify the effectiveness of βCD-SH functionalization, the capture effect of micro-motor (MXene-derived TiO2 / MnO2) without β-CD modification on PHE in the propulsion mode was explored. The results are shown in Figure 10As shown, the absorbance intensity at the maximum absorption wavelength of PHE hardly changed after the treatment of MXene-derived TiO2 / MnO2 micromotors, compared with the self-driven micromotors functionalized with β-CD-SH (propulsion mode), which indicated that even in the propulsion mode, the effective capture of PHE existing in the soil could not be achieved if no β-CD was modified on the micromotors.

[0060] The above shows and describes the basic principles, main features and advantages of the present application. However, the above description is only a specific embodiment of the present application, and the technical features of the present application are not limited thereto. Any other implementation derived by those skilled in the art without departing from the technical solution of the present application should be covered in the scope of the present application.

Claims

1. A self-propelled micromotor based on MXene, characterized by: The self-propelled micromotor TMMF-βCD is based on a MXene-derived TiO2 / MnO2 composite material obtained by mechanically exfoliating MXene-derived TiO2 with in-situ growth of MnO2 as the base skeleton. The base skeleton is modified with magnetic MnFe2O4 and β-CD. The MXene-derived TiO2 is a Ti3C2T x MXene is obtained after annealing treatment.

2. The method for preparing a MXene-based self-propelled micromotor according to claim 1, wherein: The steps include: 1) Ti3C2T in a tube furnace x MXene is annealed to obtain MXene-derived TiO2; 2) After in situ growth of MnO2 on MXene-derived TiO2 by hydrothermal method, mechanical exfoliation was performed to obtain MXene-derived TiO2 / MnO2 composite materials; 3) MnFe2O4 was modified on MXene-derived TiO2 / MnO2 composites by electrostatic adsorption; 4) β-CD was functionalized on the MnFe2O4-modified composite material by microwave heating to obtain a MXene-derived TiO2 / MnO2 / MnFe2O4-βCD self-propelled micromotor, denoted as TMMF-βCD.

3. The method for preparing a MXene-based self-propelled micromotor according to claim 2, wherein: In step 1), the heating rate is 5~12 o C min -1 , heating reaction temperature is 500~600 o C.

4. The method for preparing a MXene-based self-propelled micromotor according to claim 2, wherein: The specific process of step 2) is as follows: first disperse MXene-derived TiO2 in water, add KMnO4 and MnSO4﹒H2O for heating reaction, the mass ratio of MXene-derived TiO2, KMnO4 and MnSO4﹒H2O is 1:5~10:0.8~1.4, and the heating reaction temperature is 140~180 o C. The heating time is 10~24 h; the obtained product is added to tetrabutylammonium hydroxide solution, stirred and dispersed into water, centrifuged, and the supernatant is collected to obtain the exfoliated MXene-derived TiO2 / MnO2 composite material.

5. The method for preparing a MXene-based self-propelled micromotor according to claim 2, wherein: The specific process of step 4) is as follows: weigh the MXene-derived TiO2 / MnO2 composite material modified with MnFe2O4 and β-CD-SH in a mass ratio of 1.5-3:1, mix the two materials in water with dimethyl sulfoxide, and heat at 100-130 o The mixture was heated in a microwave oven at 400 °C for 50-70 min, centrifuged, and washed to obtain TMMF-βCD.

6. The use of the MXene-based self-propelled micromotor in the process of removing pollutants from soil according to claim 1, characterized in that: During use, 0.5 wt%~2.0 wt% H2O2 solution and TMMF-βCD are added to the system. MnO2 catalyzes the decomposition of H2O2 to produce bubbles to promote the autonomous movement of TMMF-βCD, thereby enhancing mass transfer in the soil. The pollutants are hydrophobic pollutant molecules, which can form inclusion complexes with the β-CD modified on the self-propelled micromotor TMMF-βCD based on host-guest interactions, thereby realizing dynamic capture of the pollutants. Finally, the pollutants are separated based on the magnetic recovery characteristics of the micromotor, completing the purification of the soil.

7. A device for adsorbing hydrophobic pollutants in soil, characterized in that: Including the MXene-based self-propelled micromotor according to claim 1.

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