Preparation method and application of MXene composite film with voltage gating response

Abstract

The invention relates to a preparation method and application of an MXene composite membrane with voltage gating response, and belongs to the technical field of composite materials, after MXene nanosheets are anchored by CP6 and successfully cross-linked and hybridized to obtain MXene-CP6 nanosheets, the MXene-CP6 nanosheets 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 creates a stable channel, and material aggregation is inhibited. Besides, the Mxene composite membrane further has the performance of changing the distance between the inner layers of the membrane by applying different voltages, and the change of the distance between the inner layers of the membrane is responsible for adjusting water purification to voltage stimulation. The Mxene composite membrane disclosed by the invention has stable electric response performance, and a gating effect can be realized by applying voltage, so that organic dye molecules are effectively, stably, reversibly and circularly intercepted for multiple times, and the purpose of purifying water is achieved.

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 voltage-gated response and an application thereof. Background Art

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

[0003] At present, the main methods for treating rinsing wastewater are chemical treatment and biological treatment. The chemical treatment method mainly removes suspended solids and some organic matter by adding coagulants to achieve coagulation and sedimentation, but the use of chemical agents in this method will produce a large amount of sludge, which requires further treatment, not only polluting the environment, but also increasing costs. Biological treatment methods include activated sludge method and biofilm method (degrading organic matter through microorganisms), but the high salinity, pH and residual dyes of textile wastewater will inhibit the activity of microorganisms, and additional water quality conditions need to be adjusted when used; in addition, the treatment cycle of biological treatment methods is long, and the removal effect of complex pollutants (such as heavy metals) is limited. 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 an application thereof.

[0005] In order 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: 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 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; 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. Use vacuum-assisted filtration to assemble MXene-CP6 nanosheets into regular two-dimensional channel MXene composite membranes.

[0006] Further, in step S2, the preparation method of the MXene nanosheet suspension is: etching Ti by HF generated in situ by the reaction of HCl and LiF3 AlC 2 The Al layer in the powder was then ultrasonically exfoliated and dispersed in water to obtain a MXene nanosheet suspension.

[0007] Furthermore, in step S5, the vacuum-assisted filtration method is: 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.

[0008] Another object of the present invention is to provide a MXene composite film having a voltage-gated response.

[0009] 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.

[0010] The method for treating rinsing wastewater with the MXene composite membrane is as follows: applying voltages of different magnitudes to the MXene composite membrane, realizing a gating effect by applying voltage, thereby stably, repeatedly, and reversibly cyclically intercepting organic dye molecules to achieve the purpose of purifying water.

[0011] Due to the adoption of the above technical solution, the beneficial effects of the present invention are: The present invention prepares a Mxene composite membrane with voltage gating effect to achieve efficient purification of rinsing wastewater. The interlayer spacing of the Mxene composite membrane is changed by adding voltage to achieve the change of dye interception in cross-flow filtration. This change can realize whether the interception is effective. When the Mxene composite membrane is used as a cathode, the interception effect is good, and when the Mxene composite membrane is used as an anode, the interception effect is poor. This change of good and bad effects can be repeated for multiple times.

[0012] 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 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 magnitudes, and the change in the interlayer spacing of the membrane is responsible for adjusting the water purification to the voltage stimulus. The Mxene composite membrane of the present invention has stable electrical response performance, and can achieve a gating effect by applying voltage, thereby effectively and stably, repeatedly, and reversibly cyclically intercepting organic dye molecules to achieve the purpose of purifying water.

[0013] The experiment of the present invention proves that the MXene composite membrane has a 98% methyl green rejection rate when used as a cathode in eight cycles, and drops to 0% when used as an anode. It can be seen that the present invention provides a new method for creating voltage-gated smart membranes and provides a new perspective for water treatment solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 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 methods of the present invention will become more obvious. The contents shown in the accompanying drawings are only used to explain the present invention and do not constitute any limitation to the present invention in any sense. In the accompanying drawings: Figure 1 For the present invention Ti 3 C 2 Tx nanosheets, Ti 3 C 2 Surface SEM images of Tx film, MP15 nanosheets, MP15 film, MP30 nanosheets, and MP30 film.

[0015] Figure 2 For the present invention Ti 3 C 2 Deconvoluted images of the C1s spectra of Tx nanosheets, MP15 nanosheets, and MP30 nanosheets.

[0016] Figure 3 For the present invention Ti 3 C 2 Deconvoluted images of the 01S spectra of Tx nanosheets, MP15 nanosheets, and MP30 nanosheets.

[0017] Figure 4 For the present invention Ti 3 C 2 Comparison of gating performance of Tx membrane and MP30 membrane for indigo carmine retention.

[0018] Figure 5 For the present invention Ti 3 C 2 Comparison of the gating performance of Tx membrane and MP30 membrane for methyl green retention under 5V and 10V electric fields.

[0019] 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

[0020] 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.

[0021] A method for preparing a MXene composite film with voltage-gated response comprises the following steps: S1. Under Ar atmosphere, 30 mg of CP6 (carboxylated column [6] aromatic hydrocarbon), 50 mg of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and 30 mg of N-hydroxysuccinimide were mixed; S2, stirring the mixture obtained in step S1 at room temperature for 1 h to activate the carboxyl groups in CP6, and continuing to stir at room temperature for 36 h after activation, and then adding 8 mL of 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 twice, the precipitate is redispersed in water to obtain an aqueous solution of cross-linked hybrid MXene-CP6-30 nanosheets (MP30 nanosheets).

[0022] S5. The MXene-CP6-30 nanosheets were assembled into regular two-dimensional channel MXene composite membranes, namely, MP30 membranes, using vacuum-assisted filtration.

[0023] In step S2, the preparation method of the MXene nanosheet suspension is as follows: etching Ti by HF generated in situ by the reaction of HCl and LiF 3 AlC 2 The Al layer in the powder was then ultrasonically exfoliated and dispersed in water to obtain a MXene nanosheet suspension, namely Ti 3 C 2 Tx nanosheet suspension.

[0024] Using the same method, an aqueous solution of MXene-CP6-15 nanosheets (MP15 nanosheets) was obtained by using 15 mg of CP6.

[0025] In step S5, the vacuum-assisted filtration method is as follows: 10 mL of the aqueous solution of MP30 nanosheets is diluted to a total volume of 40 mL, and then poured into a filtration device containing an MCA membrane (as a bottom membrane, ø50 mm, pore size 0.22 μm), and after standing for 10 min, vacuum filtration is performed at a pressure of 1 bar. The filtration process lasts for more than 1 h to ensure proper compaction of the MP30 membrane.

[0026] The thickness of the MP30 film can be tuned by modifying the volume of the aqueous solution of MP30 nanosheets.

[0027] Ti 3 C 2 Tx membrane and MP15 membrane were prepared in the same way.

[0028] like Figure 1 As shown, the Ti obtained in the embodiment 3 C2 Tx nanosheets, Ti 3 C 2 Tx film, MP15 nanosheet, MP15 membrane, MP30 nanosheet and MP30 membrane were characterized. Figure 1 (a) is Ti 3 C 2 Surface SEM images of Tx nanosheets; Figure 1 (b) Ti 3 C 2 Surface SEM image of Tx 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 MP30 membrane.

[0029] like Figure 2 As shown, Ti 3 C 2 The C1s core level spectrum of Tx 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.

[0030] like Figure 3 As shown, for Ti 3 C 2 Tx nanosheets, compared with MP15 nanosheets and MP30 nanosheets, the CO and C=O / -COO peak intensities increased significantly, indicating that CP6 successfully combined with Ti 3 C 2 Combined with Tx, MP15 nanosheets and MP30 nanosheets were successfully prepared.

[0031] Another object of the present invention is to provide a MXene composite film having a voltage-gated response.

[0032] 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.

[0033] The method for treating rinsing wastewater with MXene composite membrane is: applying voltages of different magnitudes 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.

[0034] Example: like Figure 4 As shown, Ti 3 C 2 Comparison of smart gating performance of Tx membrane and MP30 membrane for indigo carmine (50 ppm, 2 bar) retention.

[0035] Ti 3 C 2 The Tx membrane showed some reversible cyclic gating performance for indigo carmine, but its stability decreased after two cycles, with a retention rate of about 23% and a water flux of 17 ± 2 L m -2 h -1 bar -1 In contrast, the MP30 membrane maintained a stable electrical responsiveness even after eight cycles. When the MP30 membrane was used as a cathode at −10 V, it showed a rejection of the positively charged dye indigo carmine of nearly 80%, while reversing the electrode to +10 V reduced it to around 0% and increased the water flux to 119 ± 6.7 L m -2 h -1 bar -1 .

[0036] like Figure 5 As shown, Ti 3 C 2 Comparison of the smart gating performance of Tx membrane and MP30 membrane for methyl green (50 ppm, 2 bar) retention under 5V and 10V electric fields.

[0037] Initial Ti 3 C 2 The Tx membrane showed some reversible cyclic gating performance for methyl green (MG), but its stability decreased after two cycles, resulting in a retention rate that stabilized at 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 showed a retention rate of nearly 85% for the positively charged dye MG. Reversing the electrode to +5 V reduced the retention rate to about 30%. At -10 V, the rejection rate of MG was close to 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 by voltage modulation.

[0038] like Figure 6 As shown, the smart gating performance of MP30 membrane for Orange G, Carmine 14 and Malachite Green (50 ppm, 2 bar) is compared.

[0039] The MP30 membrane maintained stable electrical responsiveness even after eight cycles. When the MP30 membrane was used as a cathode at -10 V, it retained nearly 50% of the dye Orange G. Reversing the electrode to +10 V reduced the retention to about 0%. The MP30 membrane maintained a stable electrical response for eight cycles in the retention of Carmine 14, with a retention of about 80% when the MP30 membrane was used as a cathode at -10 V, and a retention of about 0% when the electrode was reversed to +10 V. The MP30 membrane maintained a stable electrical response for eight cycles in the retention of Malachite Green, with a retention of about 95% when the MP30 membrane was used as a cathode at -10 V, and a retention of about 0% when the electrode was reversed to +10 V, confirming that MP30 enables stable, reversible, and cyclic control of the retention of different dyes by the membrane through voltage modulation.

[0040] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation 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. Use vacuum-assisted filtration 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, characterized in that: 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, characterized in that: In step S5, the vacuum-assisted filtration method is: 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.

4. A MXene composite film with voltage-gated response, characterized in that: The MXene composite film having voltage-gated response is prepared by the method for preparing the MXene composite film having 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, realizing a gating effect by applying voltage, thereby stably, repeatedly, and reversibly cyclically intercepting organic dye molecules to achieve the purpose of purifying water.

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