Preparation method and application of MXene composite membrane with voltage-gated response

Abstract

The present invention relates to a method for preparing a MXene composite membrane with a voltage-gated response and an application thereof, belonging to the technical field of composite materials. CP6 anchors MXene nanosheets, and after successful cross-linking and hybridization to obtain MXene-CP6 nanosheets, they are assembled into a regular two-dimensional channel membrane-MXene composite membrane by a vacuum-assisted filtration method. It can be seen that the rigid CP6 structure of the present invention creates a stable channel, which suppresses material aggregation. In addition, the MXene composite membrane of the present invention also has the performance of changing the interlayer spacing of the membrane by applying voltages of different sizes. The change in the interlayer spacing of the membrane is responsible for adjusting water purification to voltage stimulation. The MXene composite membrane of the present invention has stable electrical response performance, and a gating effect can be achieved by applying a voltage to effectively stably, repeatedly, and reversibly circulate organic dye molecules to achieve the purpose of purifying water.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and in particular relates to a method for preparing a MXene composite film with a voltage-gated response and its application. Background Art

[0002] The treatment of industrial wastewater has always been very important, especially in the textile industry. Textile production produces a large amount of rinsing wastewater containing dyes. How to purify this wastewater through separation technology to obtain reusable water is very meaningful for saving water resources.

[0003] Currently, the main methods for treating rinsing wastewater include chemical treatment and biological treatment. Chemical treatment primarily removes suspended solids and some organic matter by adding coagulants, achieving coagulation and sedimentation. However, the use of chemicals in this method produces large amounts of sludge, which requires further treatment, polluting the environment and increasing costs. Biological treatment methods include activated sludge and biofilm processes (which use microorganisms to degrade organic matter). However, the high salinity, pH, and residual dyes in textile wastewater inhibit microbial activity, requiring additional water quality adjustments. Furthermore, biological treatment methods have long treatment cycles and are limited in their effectiveness at removing complex pollutants (such as heavy metals). Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a MXene composite film with a voltage-gated response and its application.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a MXene composite film with voltage-gated response, comprising the following steps:

[0006] S1. Under an inert atmosphere, CP6, N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide are mixed;

[0007] S2, stirring the mixture obtained in step S1 at room temperature to activate the carboxyl groups in CP6, continuing to stir at room temperature after activation, and then adding the MXene nanosheet suspension to the stirred mixture to react;

[0008] S3. After the reaction is completed, the precipitate is separated by centrifugation and washed with water;

[0009] S4. After repeating step S3 several times, the precipitate is redispersed in water to obtain an aqueous solution of cross-linked hybrid MXene-CP6 nanosheets;

[0010] S5. Vacuum-assisted filtration was used to assemble MXene-CP6 nanosheets into regular two-dimensional channel MXene composite membranes.

[0011] Furthermore, in step S2, the MXene nanosheet suspension is prepared by etching the Al layer in the Ti3AlC2 powder by HF generated in situ by the reaction of HCl and LiF, and then ultrasonically exfoliating and dispersing it in water to obtain the MXene nanosheet suspension.

[0012] Furthermore, in step S5, the vacuum-assisted filtration method is as follows: diluting the aqueous solution of MXene-CP6 nanosheets, then pouring it into a filtration device containing an MCA membrane, and performing vacuum filtration after standing.

[0013] Another object of the present invention is to provide a MXene composite film with voltage-gated response.

[0014] Another object of the present invention is to provide an application of a MXene composite membrane with a voltage-gated response in treating rinsing wastewater.

[0015] The method for treating rinsing wastewater with the MXene composite membrane is as follows: applying voltages of different magnitudes to the MXene composite membrane, achieving a gating effect by applying voltage, thereby stably, multiple times, and reversibly cyclically intercepting organic dye molecules to achieve the purpose of purifying water.

[0016] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0017] The present invention prepares a MXene composite membrane with a voltage-gated effect to achieve efficient purification of rinsing wastewater. By applying a voltage to change the interlayer spacing of the MXene composite membrane, the dye interception in cross-flow filtration is changed. This change can determine whether the interception is effective. When the MXene composite membrane serves as the cathode, the interception effect is good, while when the MXene composite membrane serves as the anode, the interception effect is poor. This switching of the effect can be repeated multiple times.

[0018] Specifically, the present invention anchors MXene nanosheets with carboxylated pillar[6]arene (CP6), successfully crosslinks and hybridizes to obtain MXene-CP6 nanosheets, and then assembles them into regular two-dimensional channel membranes by vacuum-assisted filtration. The rigid CP6 structure creates a stable channel, inhibits material aggregation, and increases the water flux to 119±6.7 L m -2 h -1 bar -1 Furthermore, the MXene composite membrane of the present invention has the ability to change the interlayer spacing within the membrane by applying different voltages. This change in interlayer spacing is responsible for regulating water purification to voltage stimulation. The MXene composite membrane of the present invention has stable electrical response performance. By applying voltage, a gating effect can be achieved, thereby effectively and stably, repeatedly, and reversibly cyclically intercepting organic dye molecules to achieve the purpose of water purification.

[0019] Experiments conducted in this paper demonstrate that the MXene composite membrane achieved a 98% methyl green rejection rate over eight cycles when used as a cathode, but this dropped to 0% when used as an anode. This invention provides a novel approach for creating voltage-gated smart membranes and offers a new perspective on water treatment solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be described in detail below with reference to the accompanying drawings and in combination with examples, and the advantages and implementation modes of the present invention will become more apparent. The contents shown in the accompanying drawings are only used to illustrate the present invention and do not constitute any limitation to the present invention. In the accompanying drawings:

[0021] Figure 1 Surface SEM images of Ti3C2Tx nanosheets, Ti3C2Tx films, MP15 nanosheets, MP15 films, MP30 nanosheets and MP30 films of the present invention.

[0022] Figure 2 This is a deconvolution diagram of the C1s spectra of the Ti3C2Tx nanosheets, MP15 nanosheets and MP30 nanosheets of the present invention.

[0023] Figure 3 This is a deconvolution diagram of the 01S spectra of the Ti3C2Tx nanosheets, MP15 nanosheets and MP30 nanosheets of the present invention.

[0024] Figure 4 This is a comparison chart of the gating performance of the Ti3C2Tx membrane and the MP30 membrane for indigo carmine retention of the present invention.

[0025] Figure 5 This is a comparison chart of the gating performance of the Ti3C2Tx film and the MP30 film of the present invention for methyl green retention under 5V and 10V electric fields.

[0026] Figure 6 This is a comparison chart of the gating performance of the MP30 membrane of the present invention for Orange G, Carmine 14 and Malachite Green. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the best embodiment.

[0028] A method for preparing a MXene composite film with voltage-gated response comprises the following steps:

[0029] S1. Under Ar atmosphere, mix 30 mg of CP6 (carboxylated column [6] aromatic hydrocarbon), 50 mg of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and 30 mg of N-hydroxysuccinimide;

[0030] S2. The mixture obtained in step S1 was stirred at room temperature for 1 h to activate the carboxyl groups in CP6. After activation, stirring was continued at room temperature for 36 h. Then, 8 mL of the MXene nanosheet suspension was added to the stirred mixture to react;

[0031] S3. After the reaction is completed, the precipitate is separated by centrifugation and washed with water;

[0032] S4. After repeating step S3 twice, the precipitate is redispersed in water to obtain an aqueous solution of cross-linked hybrid MXene-CP6-30 nanosheets (MP30 nanosheets).

[0033] S5. Vacuum-assisted filtration was used to assemble MXene-CP6-30 nanosheets into regular two-dimensional channel MXene composite membranes, namely MP30 membranes.

[0034] In step S2, the preparation method of the MXene nanosheet suspension is as follows: the Al layer in the Ti3AlC2 powder is etched by HF generated in situ by the reaction of HCl and LiF, and then ultrasonically exfoliated and dispersed in water to obtain a MXene nanosheet suspension, namely a Ti3C2Tx nanosheet suspension.

[0035] Using the same method, an aqueous solution of MXene-CP6-15 nanosheets (MP15 nanosheets) was obtained by using 15 mg of CP6.

[0036] In step S5, vacuum-assisted filtration was performed by diluting 10 mL of the MP30 nanosheet aqueous solution to a total volume of 40 mL. The solution was then poured into a filtration apparatus containing an MCA membrane (50 mm diameter, 0.22 μm pore size) as a base membrane. After 10 minutes of filtration, vacuum filtration was performed at a pressure of 1 bar. The filtration process lasted for at least 1 hour to ensure proper compaction of the MP30 membrane.

[0037] The thickness of the MP30 film can be tuned by modifying the volume of the aqueous solution of MP30 nanosheets.

[0038] Ti3C2Tx films and MP15 films were prepared in the same way.

[0039] like Figure 1 As shown, the Ti3C2Tx nanosheets, Ti3C2Tx films, MP15 nanosheets, MP15 films, MP30 nanosheets and MP30 films obtained in the examples were characterized. Figure 1 (a) Surface SEM image of Ti3C2Tx nanosheets; Figure 1 (b) Surface SEM image of Ti3C2Tx film; Figure 1(c) is the surface SEM image of MP15 nanosheets; Figure 1 (d) is the surface SEM image of MP15 membrane; Figure 1 (e) is the surface SEM image of MP30 nanosheets; Figure 1 (f) is the surface SEM image of the MP30 membrane.

[0040] like Figure 2 As shown, the C1s core level spectrum of Ti3C2Tx nanosheets is deconvoluted into three components at 282.1 eV, 284.8 eV, and 287 eV, corresponding to C-Ti-Tx (where T represents O, OH, and F), CC, and CO, respectively. In contrast, the CC peak intensity at 284.8 eV in MP15 and MP30 nanosheets increases significantly, demonstrating the successful preparation of MP15 and MP30 nanosheets.

[0041] like Figure 3 As shown in the figure, for Ti3C2Tx nanosheets, the CO and C=O / -COO peak intensities in MP15 nanosheets and MP30 nanosheets are significantly increased compared with those in MP15 nanosheets and MP30 nanosheets, indicating that CP6 is successfully combined with Ti3C2Tx and MP15 nanosheets and MP30 nanosheets are successfully prepared.

[0042] Another object of the present invention is to provide a MXene composite film with voltage-gated response.

[0043] Another object of the present invention is to provide an application of a MXene composite membrane with a voltage-gated response in treating rinsing wastewater.

[0044] The method for treating rinsing wastewater with MXene composite membrane is as follows: applying voltages of different sizes to the MXene composite membrane, realizing a gating effect by applying voltage, thereby stably, multiple times, and reversibly cyclically intercepting organic dye molecules to achieve the purpose of purifying water.

[0045] Example:

[0046] like Figure 4 As shown, the smart gating performance comparison of Ti3C2Tx membrane and MP30 membrane for indigo carmine (50 ppm, 2 bar) rejection.

[0047] The Ti3C2Tx membrane showed some reversible cyclic gating performance for indigo carmine, but its stability decreased after two cycles, with a rejection of around 23% and a water flux of 17 ± 2 L m -2 h -1 bar -1In contrast, the MP30 membrane maintained stable electrical responsiveness even after eight cycles. When the MP30 membrane was used as a cathode at -10 V, its rejection of the positively charged dye indigo carmine was close to 80%, while reversing the electrode to +10 V reduced this to around 0% and increased the water flux to 119 ± 6.7 L m -2 h -1 bar -1 .

[0048] like Figure 5 As shown in the figure, the smart gating performance comparison of Ti3C2Tx membrane and MP30 membrane for methyl green (50 ppm, 2 bar) retention under 5V and 10V electric fields.

[0049] The initial Ti3C2Tx membrane showed some reversible cyclic gating performance for methyl green (MG), but its stability decreased after two cycles, resulting in a stable rejection of around 50%. In contrast, the MP30 membrane maintained stable electrical responsiveness even after eight cycles. When the membrane was used as a cathode at -5 V, it rejected the positively charged dye MG at nearly 85%. Reversing the electrode to +5 V reduced the rejection to approximately 30%. At -10 V, the rejection of MG approached 100%, while reversing the electrode to +10 V reduced it to around 0%. After eight cycles under both voltage conditions, the inhibition cycles ranged from 0% to 100%, confirming that the MP30 membrane enables stable, reversible, and cyclic control of the inhibition level through voltage modulation.

[0050] like Figure 6 Figure 2 shows the comparison of the smart gating performance of MP30 membrane for Orange G, Carmine 14, and Malachite Green (50 ppm, 2 bar).

[0051] The MP30 membrane maintained stable electrical responsiveness even after eight cycles. When the MP30 membrane was used as a cathode at -10 V, its rejection of the dye Orange G was close to 50%. Reversing the electrode to +10 V reduced the rejection to approximately 0%. The MP30 membrane also maintained a stable electrical response for eight cycles in the rejection of Carmine 14. When the MP30 membrane was used as a cathode at -10 V, its rejection of Carmine 14 was approximately 80%, which was reduced to approximately 0% by reversing the electrode to +10 V. The MP30 membrane also maintained a stable electrical response for the rejection of Malachite Green over eight cycles. When the MP30 membrane was used as a cathode at -10 V, its rejection of Malachite Green was approximately 95%, which was reduced to approximately 0% by reversing the electrode to +10 V. This demonstrates that MP30 enables stable, reversible, and cyclic control of the membrane's rejection of different dyes through voltage modulation.

[0052] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for preparing a MXene composite film with voltage-gated response, characterized in that: The following steps are involved: S1. Under an inert atmosphere, CP6, N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide are mixed; S2, stirring the mixture obtained in step S1 to activate the carboxyl groups in CP6, continuing stirring after activation, and then adding the MXene nanosheet suspension to the stirred mixture to react; S3. After the reaction is completed, the precipitate is separated by centrifugation and washed with water; S4. After repeating step S3 several times, the precipitate is redispersed in water to obtain an aqueous solution of cross-linked hybrid MXene-CP6 nanosheets; S5. Vacuum-assisted filtration was used to assemble MXene-CP6 nanosheets into regular two-dimensional channel MXene composite membranes.

2. The method for preparing a MXene composite film with voltage-gated response according to claim 1, wherein: In step S2, the MXene nanosheet suspension is prepared by etching the Al layer in the Ti3AlC2 powder by HF generated in situ by the reaction of HCl and LiF, followed by ultrasonic exfoliation and dispersion in water to obtain the MXene nanosheet suspension.

3. The method for preparing a MXene composite film with voltage-gated response according to claim 1, wherein: In step S5, the vacuum-assisted filtration method is as follows: diluting the aqueous solution of MXene-CP6 nanosheets, then pouring it into a filtration device containing an MCA membrane, and then vacuum filtering after standing.

4. A MXene composite film with voltage-gated response, characterized in that: It is prepared by the method for preparing a MXene composite film with voltage-gated response according to any one of claims 1 to 3.

5. Application of a MXene composite membrane with voltage-gated response in treating rinsing wastewater, characterized in that: This is achieved by the MXene composite film with voltage-gated response as described in claim 4.

6. The use of the MXene composite membrane with voltage-gated response in treating rinsing wastewater according to claim 5, characterized in that: The method for treating rinsing wastewater with the MXene composite membrane is as follows: applying voltages of different magnitudes to the MXene composite membrane, achieving a gating effect by applying voltage, thereby stably, multiple times, and reversibly cyclically intercepting organic dye molecules to achieve the purpose of purifying water.

Images