MXene-based self-driven micro motor, preparation method and application thereof

Abstract

The invention discloses a self-driven micromotor based on MXene, a preparation method and application thereof, and belongs to the technical field of environmental restoration. According to the self-driven micromotor TMMF-betaCD, MXene-derived TiO2 serves as a substrate framework, MnO2 grows on the framework in situ and then is mechanically stripped to obtain an MXene-derived TiO2 / MnO2 composite material, then MnFe2O4 is modified on the composite material by using an electrostatic adsorption method to endow the material with a magnetic recovery characteristic, and finally beta-CD is functionally modified on the composite material by using a microwave heating method, so that the self-driven micromotor TMMF-betaCD is prepared. When TMMF-betaCD and hydrogen peroxide jointly act on treatment of hydrophobic pollutants (such as polycyclic aromatic hydrocarbon) in soil, MnO2 catalyzes decomposition of hydrogen peroxide to generate bubbles to push the TMMF-betaCD to move autonomously, mass transfer in the soil is greatly enhanced, dynamic capture of the pollutants in the soil is achieved based on host-guest interaction between beta-CD and pollutant molecules, and the soil quality is improved. Finally, the effect of purifying the soil is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental remediation, and in particular to a MXene-based self-driven micromotor, a preparation method and applications thereof. Background Art

[0002] The acceleration of industrialization and urbanization has inevitably brought about corresponding environmental problems, among which soil pollution has become the focus of social attention. Polycyclic aromatic hydrocarbons (PAHs) are one of the most common pollutants in soil. They have strong hydrophobicity and low water solubility, which makes them difficult to detect and remove in the environment. Their main sources are anthropogenic 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 precipitation. They are persistent, bioaccumulative, and toxic, and can induce cancer, respiratory damage, skin and eye irritation, digestive damage, cardiovascular system diseases, immune system diseases, and affect reproduction and development, posing a huge 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. Among them, advanced oxidation processes (AOPs) have attracted much attention 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 the problems of long time consumption, reduced soil nutrients and the production of harmful degradation products. Therefore, it is urgent to develop a simple, convenient, fast-acting removal method that will not cause secondary pollution.

[0004] In recent years, self-propelled micromotors have been effectively used in environmental cleaning and medical applications due to their unique characteristics of autonomous motion and high power output. Unlike traditional micro / nanoparticles whose motion process relies on Brownian motion and passive diffusion, micro / nanomotors can move autonomously using energy generated by external stimuli (light, ultrasound, electricity, magnetic field, etc.) or chemical reactions (reaction fuels include H2O2, glucose, urea, water, etc.). The self-propelled motion of micro / nanomotors can make the surrounding fluids mix more strongly between contaminated samples, thereby accelerating the degradation of pollutants. In particular, for micro / nanomotors that rely on bubble driving force to achieve self-propelled motion, the continuously generated microbubbles 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 micromotors can improve the transport efficiency in underground environments and achieve effective in-situ soil purification. Therefore, the design of suitable self-propelled micromotors is expected to solve the related problems faced when using traditional methods to remediate soil.

[0005] MXene is a promising two-dimensional material that can be used to make micromotors. Its general formula is M n+1 X n T x (n=1, 2, 3), where M is a transition metal (Ti, Mo, V), X is carbon or nitrogen, T x It 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 cyclic molecular structure of "hydrophobic inside and hydrophilic outside". β-CD is widely used due to its low production cost. The internal cavity of CD is highly hydrophobic and shows a strong affinity for hydrophobic guest molecules. Therefore, 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 molecule in the CD cavity to form a host-guest inclusion complex, thereby changing the solubility properties of the compound. Therefore, CD is often used in solid phase extraction experiments of PAHs. CD, as part of the fiber coating, selectively adsorbs and enriches PAHs to enhance the sensitivity and accuracy of its detection and measurement.

[0007] However, there is no precedent in the existing technology for combining CD with micro / nanomotors for dynamic capture and removal of PAHs in soil. It is still unclear how to effectively functionalize CD on the corresponding micro / nanomotors, and the corresponding preparation process and removal mechanism still need further in-depth exploration. Summary of the invention

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

[0009] In order to achieve the above technical objectives, the present invention is implemented by the following technical solutions: the MXene-based self-driven micromotor TMMF-βCD uses a MXene-derived TiO2 / MnO2 composite material obtained by mechanically exfoliating MXene-derived TiO2 with in-situ growth of MnO2 as the base skeleton, and the base skeleton is modified with magnetic MnFe2O4 and β-CD, and the MXene-derived TiO2 is a Ti3C2T xMXene is obtained after annealing treatment.

[0010] Furthermore, the self-driven micromotor can utilize the bubbles generated by the decomposition of hydrogen peroxide catalyzed by the composite MnO2 to obtain driving force to enhance mass transfer.

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

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

[0013] 1) Ti3C2T in a tube furnace x MXene is annealed to obtain MXene-derived TiO2;

[0014] 2) In situ growth of MnO2 on MXene-derived TiO2 by a hydrothermal method followed by mechanical exfoliation to obtain a MXene-derived TiO2 / MnO2 composite material;

[0015] 3) Modification of MnFe2O4 on MXene-derived TiO2 / MnO2 composites by electrostatic adsorption;

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

[0017] Furthermore, in step 1), the heating rate is 5-12°C min -1 , the heating reaction temperature is 500-600℃.

[0018] Furthermore, the specific process of step 2) is: first disperse the 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, the heating reaction temperature is 140-180°C, and the heating time is 10-24h; the obtained product is added to a tetrabutylammonium hydroxide solution, dispersed in water after stirring, centrifuged, and the supernatant is collected to obtain an exfoliated MXene-derived TiO2 / MnO2 composite material.

[0019] Furthermore, the specific process of step 4) is: weigh the MXene-derived TiO2 / MnO2 composite material modified with MnFe2O4 and β-CD-SH in a mass ratio of 1.5 to 3:1, mix the two materials in water added with dimethyl sulfoxide, microwave heat at 100 to 130°C for 50 to 70 minutes, centrifuge, and wash to obtain TMMF-βCD.

[0020] The above-mentioned MXene-based self-propelled micromotor can be used in the process of removing hydrophobic pollutants in the soil. When in use, 0.5wt%~2.0wt% 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 and enhance the mass transfer effect in the soil. The pollutants are hydrophobic pollutant molecules. The pollutant molecules can form inclusion complexes with the β-CD modified on the self-propelled micromotor TMMF-βCD based on host-guest interaction, thereby realizing dynamic capture of pollutants. Finally, the separation rate of pollutants is achieved based on the magnetic recovery characteristics of the micromotor, thereby completing the purification of the soil.

[0021] Using the MXene-based self-propelled micromotor as an adsorption material, a device for adsorbing hydrophobic pollutants in soil can be constructed. It is then expected that a complete industrial soil remediation system can be built based on this device for environmental soil remediation.

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

[0023] 1. In the present application, MnO2 is grown in situ on MXene-derived TiO2 by a hydrothermal method, and then mechanically exfoliated to obtain a MXene-derived TiO2 / MnO2 composite material and used as a base skeleton. Then, MnFe2O4 is modified on the composite material by an electrostatic adsorption method to make it recyclable. Finally, under microwave heating conditions, β-CD-SH is used to further functionalize the composite material to obtain the self-driving micromotor TMMF-βCD that the present application wants to protect;

[0024] 2. The self-driving micromotor TMMF-βCD disclosed in the present application is applied together with hydrogen peroxide in practical application. The hydrogen peroxide is decomposed by MnO2, and the ejected micro-nano bubbles can drive the micromotor to move autonomously. The driving force obtained thereby gives the material the ability to self-drive in the soil, greatly enhancing the mass transfer effect in the soil, and facilitating the increase of the chance of collision and contact between the micromotor functional component β-CD and polycyclic aromatic hydrocarbons, thereby enhancing the host-guest interaction between the two. β-CD includes polycyclic aromatic hydrocarbons to achieve dynamic capture of polycyclic aromatic hydrocarbons in the soil, thereby enabling the polycyclic aromatic hydrocarbon pollutants to be effectively adsorbed and removed from the soil, thereby improving the pollutant adsorption efficiency and achieving the effect of purifying the soil without external energy input;

[0025] 3. Since the self-driving micromotor TMMF-βCD disclosed in the present application has magnetism, it can separate, recycle, process and reuse pollutants in the soil through simple magnetic control operation after capturing them, without causing secondary pollution, and meets the requirements of green environmental protection;

[0026] 4. The self-propelled micromotor TMMF-βCD disclosed in this application is not only suitable for removing polycyclic aromatic hydrocarbons in soil, but other hydrophobic pollutants that can form inclusion complexes with the β-CD molecules modified on the micromotor through host-guest interactions can also be effectively removed by the method disclosed in this application, with good universality;

[0027] 5. The self-driving micromotor TMMF-βCD disclosed in the present application is green and environmentally friendly, has high yield, and has a simple preparation process without the need for expensive instruments and materials. It has significant environmental and economic benefits and is suitable for the mass preparation of environmental functional materials, with good application prospects. In addition, the successful preparation and application of this material also provides a new solution for the removal of pollutants in the environment and a new reference mechanism for the restoration and purification of soil.

[0028] 6. This application is the first to use in situ electrochemical impedance spectroscopy and relaxation time to monitor the kinetic process of removing PAHs from soil, revealing the effective migration of micromotors in heterogeneous environments and the dynamic capture mechanism of PAHs by autonomously propelled micromotors. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart for preparing the MXene-based self-propelled micromotor TMMF-βCD disclosed in Example 1;

[0030] Figure 2 is a diagram of the preparation process of the MXene-based self-driving micromotor TMMF-βCD disclosed in Example 1;

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

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

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

[0034] Figure 6 is the relationship between the concentration of hydrogen peroxide and the movement speed of the self-driven micromotor TMMF-βCD;

[0035] Figure 7 This is the mechanism diagram of the self-propelled micromotor TMMF-βCD capturing PAHs in soil samples;

[0036] Figure 8Panels a and b in the middle are Nyquist plots of using the self-driven micromotor TMMF-βCD to remove PHE from the soil; Panel c is an image obtained by DRT analysis of the process of removing PHE from the soil by the self-driven micromotor TMMF-βCD;

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

[0038] Fig.10 These are quantitative test images of the unmodified β-CD self-driven micromotor adsorbing polycyclic aromatic hydrocarbons in soil. Panel a is the corresponding UV contour map, and panel b is the UV spectrum map. DETAILED DESCRIPTION

[0039] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the essence of the present invention, modifications and substitutions made to the methods, steps or conditions of the present invention all fall within the scope of the present invention.

[0040] Example 1

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

[0042] S101: 1.3 g LiF was added to 20 mL 9 M HCl solution and stirred until completely dissolved, 0.5 g Ti3AlC2 MAX phase powder was slowly added, stirred at 35 °C for 24 h, and washed with deionized water until pH ~ 6. The washed product was freeze-dried for 3 days to obtain Ti3C2T x Mxene. In air atmosphere, Ti3C2T x The MXene was transferred to a tube furnace and heated at 10 °C min -1 The temperature was raised to 550°C at a heating rate of 100 °C, maintained for 10 min, then cooled to room temperature and collected to obtain MXene-derived TiO2 (multilayer TiO2).

[0043] S102: 150mg MXene-derived TiO2 was dispersed in 30mL deionized water, 950mg KMnO4 and 169mg MnSO4·H2O were added, and stirred for 30min. The mixture was transferred to a high-pressure reactor and reacted at 160°C for 12h. The product was collected by centrifugation, washed with water and ethanol several times, and 200mg was added to 8mL tetrabutylammonium hydroxide (TBAOH, 54%) solution after the successful in-situ growth of MnO2 on MXene-derived TiO2. After stirring for 2h, it was dispersed in 45mL deionized water, shaken for 5min, centrifuged at 2000rpm for 30min (3-4 times), and the supernatant was collected to obtain the 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, transferred to an autoclave, and heated at 200°C for 10 h. The product was collected by centrifugation and washed several times with water and ethanol to obtain MnFe2O4.

[0045] A: 15 mg MnFe2O4 was added to a mixed solution of 2 mL 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), A and B were mixed and stirred at room temperature for 1 h to modify the nanoparticles. Finally, magnetic collection was performed, washed twice in ultrapure water and ethanol, and dried overnight. The magnetic MXene-derived TiO2 / MnO2 / MnFe2O4 self-driven micromotors (TM / MnFe2O4) were obtained.

[0046] S104: 50 mg of MXene-derived TiO2 / MnO2 / MnFe2O4 was mixed with 30 mg of mercapto-β-cyclodextrin (β-CD-SH) in 25 mL of deionized water and heated in a microwave at 110 °C for 60 min. When β-CD-SH was used, 250 μL of dimethyl sulfoxide (DMF) was added to 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 micromotor (denoted as TMMF-βCD).

[0047] Related performance tests

[0048] 1. The MXene-derived TiO2 / MnO2 and TMMF-βCD prepared in this example were tested by scanning electron microscopy (SEM). Figure 3 As shown, from Figure 3As can be seen in the middle panel a, MnO2 nanosheets are in situ grown on MXene-derived TiO2. Figure 3 In panels b, e, and f, it can be observed that MnFe2O4 nanoparticles are 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. The results are shown in Figure 4 The graphic results show that Ti, Mn, O, S, Fe, and C are uniformly distributed on TMMF-βCD, which proves that the MXene-based self-driven micromotor 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 high HLB value (Hydrophilic Lipophilic Balance) of SDS, which means that it has good hydrophilicity, 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, 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 when it is actually used for 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 , relative to soil mass), a mixed solution of 2.0wt% hydrogen peroxide and 0.5wt% SDS was dropped on a glass slide. Images were taken using an optical microscope equipped with an OLYMPUS cellSensDimension system. Motion time-lapse images can be found at 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 on glass slides. The movement speed of the micromotor was photographed and analyzed using an optical microscope equipped with an OLYMPUS cellSensDimension system. The results are shown in 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. In order to study the capture mechanism of polycyclic aromatic hydrocarbons (PAHs) pollutants adsorbed by TMMF-βCD in soil, simulation experiments were conducted using phenanthrene (PHE), a representative PAH widely present in soil, as a model pollutant to reveal the mechanism of pollutant capture in soil.

[0053] like Figure 7 As shown, the self-propelled micromotor generates local convection and mixing, which enhances 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 will increase. Subsequently, when the micromotor collides with 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, which is the driving force for extracting the PHE molecules from the soil and forming the inclusion complex to be tested. Finally, since 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 enough pollutants for direct monitoring without complex pretreatment.

[0054] 6. In order to study the process of PHE capture in soil by MXene-based self-propelled micromotors, we used in situ EIS technique 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 in-situ EIS measurement reveals 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. ctThe increase in the reaction depth significantly reflects the delay in kinetics due to the continuous adsorption and encapsulation of PHE molecules on the surface of TMMF-βCD. The above kinetic analysis verifies that TMMF-βCD can effectively migrate in the soil due to its efficient self-propulsion, and on the other hand, it verifies the dynamic capture of PHE in the soil by the propulsion micromotor.

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

[0057] The collected soil was first screened using 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 resulting suspension was thoroughly mixed on a rotary vibrating screen, and then the acetonitrile was evaporated under a fume hood for 2 days. The contaminated soil samples were aged in a fume hood for two months before use. For the decontamination test, the contaminated soil was first pretreated by mixing the contaminated soil with deionized water to form a slurry (water-soil mass ratio of 2:1), and then TMMF-βCD (10 g kg -1 , relative to soil mass) and H2O2 were studied for their adsorption properties and quantitatively determined by UV-visible spectrometry.

[0058] The results are as follows Fig. 9 As shown, Fig. 9 The self-propelled micromotor TMMF-βCD was demonstrated to operate in both static and propulsion modes (TMMF-βCD (10 g kg -1 , relative to soil mass) and 2.0wt% hydrogen peroxide, the static group only added TMMF-βCD (10g kg -1 , relative to soil mass) without the addition of hydrogen peroxide). Fig. 9 Compared with the push mode ( Fig. 9 After treatment under the conditions of (c and d) in the middle, the maximum absorption wavelength (λ max =251) underwent a very significant intensity change. In the propulsion mode, the absorbance of PHE dropped sharply, indicating that PHE was successfully removed from the soil. The obvious difference between the static group and the propulsion group shows that the self-driving of the micromotor can improve the PHE capture efficiency when processing soil samples, because the movement of the self-driven micromotor enhances its contact with PHE.

[0059] In addition, to verify the effectiveness of β-CD-SH functionalization, the capture effect of PHE by the micromotor (MXene-derived TiO2 / MnO2) without β-CD modification in propulsion mode was explored. Fig.10As shown, compared with the self-propelled micromotors functionalized with β-CD-SH (propulsion mode), the absorbance intensity at the maximum absorption wavelength of PHE was almost unchanged after treatment with MXene-derived TiO2 / MnO2 micromotors, indicating that even in the propulsion mode, effective capture of PHE present in the soil cannot be achieved without β-CD modification on the micromotors.

[0060] The above shows and describes the basic principles, main features and advantages of the present invention. However, the above is only a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other implementation methods derived by any technician in the field without departing from the technical solution of the present invention should be included in the scope of the present invention.

Claims

1. A self-propelled micromotor based on MXene, characterized in that: The self-propelled micromotor TMMF-βCD uses a MXene-derived TiO2 / MnO2 composite material obtained by mechanically exfoliating MXene-derived TiO2 grown in situ with 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 MXene-based self-driving micromotor according to claim 1, characterized in that: The self-propelled micromotor can utilize the bubbles generated by the decomposition of hydrogen peroxide catalyzed by MnO2 to obtain driving force to enhance mass transfer.

3. The MXene-based self-driven micromotor according to claim 1, characterized in that: This self-propelled micromotor has the characteristics of magnetically controlled directional motion and can be magnetically recycled.

4. The method for preparing a MXene-based self-driven micromotor according to any one of claims 1 to 3, characterized in that: The steps include: 1) Ti3C2T in a tube furnace x MXene is annealed to obtain MXene-derived TiO2; 2) In situ growth of MnO2 on MXene-derived TiO2 by a hydrothermal method followed by mechanical exfoliation to obtain a MXene-derived TiO2 / MnO2 composite material; 3) Modification of MnFe2O4 on MXene-derived TiO2 / MnO2 composites by electrostatic adsorption; 4) β-CD was functionalized on the composite material modified with MnFe2O4 by microwave heating to obtain MXene-derived TiO2 / MnO2 / MnFe2O4-βCD self-driven micromotor, denoted as TMMF-βCD.

5. The method for preparing a MXene-based self-driven micromotor according to claim 4, characterized in that: In step 1), the heating rate is 5-12°C min -1 , the heating reaction temperature is 500-600℃.

6. The method for preparing a MXene-based self-driven micromotor according to claim 4, characterized in that: The specific process of step 2) is as follows: firstly, MXene-derived TiO2 is 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 to tetrabutylammonium hydroxide solution, dispersed in water after stirring, centrifuged, and the supernatant is collected to obtain the exfoliated MXene-derived TiO2 / MnO2 composite material.

7. The method for preparing a MXene-based self-driven micromotor according to claim 4, characterized in that: The specific process of step 4) is: weigh the MXene-derived TiO2 / MnO2 composite material modified with MnFe2O4 and β-CD-SH in a mass ratio of 1.5 to 3:1, mix the two materials in water added with dimethyl sulfoxide, microwave heat at 100 to 130°C for 50 to 70 minutes, centrifuge, wash, and obtain TMMF-βCD.

8. The use of a MXene-based self-driven micromotor in the process of removing pollutants from soil as claimed in any one of claims 1 to 3, characterized in that: When in use, 0.5wt% to 2.0wt% H2O2 solution and TMMF-βCD are added to the system, and MnO2 catalyzes the decomposition of H2O2 to generate bubbles to promote the autonomous movement of TMMF-βCD, thereby enhancing the mass transfer effect in the soil; the pollutants are hydrophobic pollutant molecules, and the pollutant molecules can form inclusion complexes with the β-CD modified on the self-driving micromotor TMMF-βCD based on host-guest interaction, thereby realizing dynamic capture of the pollutants, and finally realizing the separation of the pollutants based on the magnetic recovery characteristics of the micromotor, thereby completing the purification of the soil.

9. A device for adsorbing hydrophobic pollutants in soil, characterized in that: A MXene-based self-driving micromotor comprising any one of claims 1-3.

10. An industrial soil remediation system, characterized in that: A device for adsorbing hydrophobic pollutants in soil as claimed in claim 9.

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