Controllable preparation method of defect-rich titanium carbide and application thereof

Abstract

The application relates to a controllable preparation method of defect-rich titanium carbide and application thereof and belongs to the technical fields of material preparation and water treatment. x The existing method has the problems of poor catalytic activity and few surface active sites. The multilayer titanium carbide is prepared by etching a Ti3AlC2 MAX phase through hydrofluoric acid, and the few-layer titanium carbide is successfully prepared through centrifugal ultrasonic operation, a low-energy-consumption high-efficiency activated PAA advanced oxidation system is constructed, and the catalytic degradation activity of the emerging pollutant CBZ is explored; compared with unmodified Ti3AlC2 and multilayer Ti3C2T x , the few-layer Ti3C2T x Can expose more defect sites and active surfaces to improve the catalytic activity. The application has good catalytic degradation performance on CBZ, and provides a new idea for the removal of emerging pollutants in water environment. The application can obtain defect-rich titanium carbide.

Description

Technical Field

[0001] This invention belongs to the field of materials preparation and water treatment technology, specifically relating to a controllable preparation method for defect-rich titanium carbide and its application. Background Technology

[0002] With the acceleration of industrialization, environmental pollution has become increasingly severe, and water pollution problems have become more and more serious. This has led to the frequent detection of emerging pollutants (ECs) in drinking water sources, including pharmaceuticals and personal care products (PPCPs), persistent organic pollutants (POPs), and endocrine disruptors (EDCs). However, most PPCPs cannot be removed by conventional wastewater treatment processes and enter surface water systems, posing a potential impact on human health and ecological safety. Therefore, there is an urgent need to develop a highly efficient PPCP treatment technology.

[0003] Currently, there is no dedicated equipment for treating PPCPs in wastewater treatment systems. This leads to problems such as low PPCP removal rates and high effluent PPCP content in wastewater treatment plants, indirectly causing an increase in pollutant concentrations in the natural environment. Therefore, researching and developing treatment processes that can efficiently remove PPCPs from wastewater is of great practical significance.

[0004] Peracetic acid (PAA)-based advanced oxidation processes (AOPs) are among the most promising technologies for removing emerging pollutants from water due to their strong oxidizing power and low generation of toxic byproducts. The development of efficient catalysts to activate PAA and accelerate the degradation of organic pollutants has attracted widespread attention from researchers.

[0005] As emerging two-dimensional materials, transition metal carbides, nitrides, and carbonitrides (MXenes) possess broad transition metal planes, hydrophilic terminal functional groups (-O, -OH, or -F), and easily tunable surface / interface structures, making them widely applicable in environmental remediation, energy storage, and biomedicine. Ti3C2T x With its high specific surface area, abundant terminal groups, and ease of functionalization, Ti3C2T is widely used as a co-catalyst, providing an ideal platform for PAA activation. However, Ti3C2T x Mxenes-activated PAA is still in the early stages of research, with only a small number of studies focusing on improving Ti3C2T through modification. x The catalytic properties of the material enable it to degrade pollutants more rapidly.

[0006] Currently, bulk and multilayer Ti3C2T x There has been considerable research on Ti3C2T as a catalyst; however, bulk and multilayer Ti3C2T... x It has drawbacks such as poor catalytic activity and few surface active sites. Compared with bulk and multilayer Ti3C2T... xFew-layer Ti3C2T x This can expose more defect sites and active surfaces, thereby improving catalytic activity. Summary of the Invention

[0007] The purpose of this invention is to solve the problems of bulk and multilayer Ti3C2T prepared by existing methods. x This paper addresses the problems of poor catalytic activity and few surface active sites in titanium carbide, and provides a controllable preparation method for defect-rich titanium carbide and its application.

[0008] This invention first prepared multilayer titanium carbide by etching the Ti3AlC2 MAX phase with hydrofluoric acid, and then successfully prepared few-layer titanium carbide through centrifugation and sonication. A low-energy, high-efficiency PAA (peracetic acid) advanced oxidation system was constructed to investigate its catalytic degradation activity against the emerging pollutant CBZ (carbamazepine). Compared with unmodified Ti3AlC2 and multilayer Ti3C2T... x Few-layer Ti3C2T x This allows for the exposure of more defect sites and active surfaces, thereby enhancing catalytic activity. In summary, this invention successfully prepared a defect-rich titanium carbide catalyst with excellent catalytic degradation performance for CBZ, providing a new approach for the removal of emerging pollutants in the aquatic environment.

[0009] A controllable preparation method for defect-rich titanium carbide is specifically carried out according to the following steps:

[0010] 1. Mix Ti3AlC2 and hydrofluoric acid solution evenly, then put it into a polytetrafluoroethylene bottle and stir it in a constant temperature water bath for a certain period of time to obtain a mixed solution.

[0011] 2. Pour the mixed solution into a centrifuge tube, centrifuge it in a centrifuge, and wash the mixed solution repeatedly with deionized water until the supernatant after centrifugation is neutral;

[0012] 3. After centrifugation, the precipitate was collected and dried in a vacuum drying oven, then collected in a sealed bag to obtain multilayer Ti3C2T. x ;

[0013] IV. Multilayer Ti3C2T x LiF and hydrochloric acid are mixed evenly and then placed in a polytetrafluoroethylene bottle to react for a period of time to obtain the reaction product.

[0014] 5. Place the reaction product in a centrifuge tube, centrifuge it, and wash the reaction product repeatedly with deionized water until the supernatant after centrifugation is neutral. Collect the precipitate after centrifugation.

[0015] 6. The precipitate after centrifugation is added to oxygen-free deionized water and ultrasonically exfoliated in an ice bath under argon protection for a certain period of time to obtain the ultrasonically treated solution.

[0016] 7. Centrifuge the ultrasonically treated solution for a certain period of time to obtain the exfoliated few-layer Ti3C2T x Supernatant;

[0017] 8. The use of fewer layers of Ti3C2T x Centrifuge the supernatant for a certain period of time and collect the precipitate after centrifugation.

[0018] 9. After centrifugation, the precipitate is freeze-dried for a certain period of time and collected in a sealed bag to obtain defect-rich titanium carbide.

[0019] Advantages of this invention:

[0020] I. This invention provides a controllable preparation method for defect-rich titanium carbide and its application. Because centrifugation, sonication and other operations can break the inherent interface of multilayer titanium carbide, compared with multilayer titanium carbide, fewer-layer titanium carbide can expose more defect sites and active surfaces, thereby improving catalytic activity and better activating PAA, and has a good removal effect on emerging pollutants in water.

[0021] Second, in the defect-rich titanium carbide / PAA system of this invention, the degradation rate of CBZ is relatively fast in the first 5 minutes, and about 70% of CBZ can be degraded. At the end of the reaction, about 75% of CBZ can be degraded. Attached Figure Description

[0022] Figure 1 The multilayer Ti3C2T prepared in step three of Example 1 x SEM image of (BT);

[0023] Figure 2 The few-layer Ti3C2T prepared in step nine of Example 1 x (FT) TEM image;

[0024] Figure 3 The Ti3AlC2 in Comparative Example 1 and the few-layer Ti3C2T prepared in step nine of Example 1 x (FT) Zeta potential plot;

[0025] Figure 4 For the Ti3AlC2 in Comparative Example 1 and the multilayer Ti3C2T prepared in step three of Example 1 x (BT) and the few-layer Ti3C2T prepared in step nine of Example 1 x (FT) XRD pattern;

[0026] Figure 5 For application experiments, the multilayer Ti3C2T prepared in step three of Comparative Example 1 and Comparative Example 1 were used. x(BT) and the few-layer Ti3C2T prepared in step nine of Example 1 x (FT) Performance diagram of PAA-activated degradation of CBZ. Detailed Implementation

[0027] Specific Implementation Method 1: This implementation method provides a controllable preparation method for defect-rich titanium carbide, which is specifically completed according to the following steps:

[0028] 1. Mix Ti3AlC2 and hydrofluoric acid solution evenly, then put it into a polytetrafluoroethylene bottle and stir it in a constant temperature water bath for a certain period of time to obtain a mixed solution.

[0029] 2. Pour the mixed solution into a centrifuge tube, centrifuge it in a centrifuge, and wash the mixed solution repeatedly with deionized water until the supernatant after centrifugation is neutral;

[0030] 3. After centrifugation, the precipitate was collected and dried in a vacuum drying oven, then collected in a sealed bag to obtain multilayer Ti3C2T. x ;

[0031] IV. Multilayer Ti3C2T x LiF and hydrochloric acid are mixed evenly and then placed in a polytetrafluoroethylene bottle to react for a period of time to obtain the reaction product.

[0032] 5. Place the reaction product in a centrifuge tube, centrifuge it, and wash the reaction product repeatedly with deionized water until the supernatant after centrifugation is neutral. Collect the precipitate after centrifugation.

[0033] 6. The precipitate after centrifugation is added to oxygen-free deionized water and ultrasonically exfoliated in an ice bath under argon protection for a certain period of time to obtain the ultrasonically treated solution.

[0034] 7. Centrifuge the ultrasonically treated solution for a certain period of time to obtain the exfoliated few-layer Ti3C2T x Supernatant;

[0035] 8. The use of fewer layers of Ti3C2T x Centrifuge the supernatant for a certain period of time and collect the precipitate after centrifugation.

[0036] 9. After centrifugation, the precipitate is freeze-dried for a certain period of time and collected in a sealed bag to obtain defect-rich titanium carbide.

[0037] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the mass fraction of the hydrofluoric acid solution in step one is 30%–70%; the mass ratio of Ti3AlC2 to the volume of the hydrofluoric acid solution in step one is (2g–4g):(100mL–150mL); the water bath stirring temperature in step one is 40℃–60℃, and the water bath stirring time is 12h–24h. Other steps are the same as in Specific Implementation Method One.

[0038] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the centrifugation speed in step two is 6000 rpm to 8000 rpm, and the centrifugation time is 3 min / cycle to 10 min / cycle. Other steps are the same as in Specific Implementation Method One or Two.

[0039] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the vacuum drying temperature in step three is 60℃~80℃, and the vacuum drying time is 24h~48h. The other steps are the same as in Specific Implementation Methods One to Three.

[0040] Specific Implementation Method Five: The difference between this implementation method and Specific Implementation Methods One to Four is that the multilayer Ti3C2T described in step four... x The mass-to-volume ratio of LiF and hydrochloric acid is (2g-4g):(2g-4g):(100mL-150mL); the concentration of the hydrochloric acid is 9mol / L-15mol / L; the reaction temperature in step four is 40℃-60℃, and the reaction time is 12h-24h. Other steps are the same as in specific embodiments one through four.

[0041] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the centrifugation speed in step five is 6000 rpm to 8000 rpm, and the centrifugation time is 3 min / cycle to 10 min / cycle. The other steps are the same as in Specific Implementation Methods One to Five.

[0042] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One through Six in that: the mass ratio of the precipitate after centrifugation to the volume of deionized water in step six is ​​(2g-4g):(100mL-150mL); the ultrasonication time in step six is ​​1h-3h, and the ultrasonication power is 250W-750W. Other steps are the same as in Specific Implementation Methods One through Six.

[0043] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in the following ways: In step Seven, the centrifugation speed is 3500 rpm to 5000 rpm, and the centrifugation time is 10 min to 20 min; in step Eight, the centrifugation speed is 12000 rpm to 15000 rpm, and the centrifugation time is 60 min to 100 min; in step Nine, the freeze-drying temperature is -10℃ to -50℃, and the freeze-drying time is 36 h to 72 h. Other steps are the same as in Specific Implementation Methods One to Seven.

[0044] Specific Implementation Method Nine: This implementation method uses defect-rich titanium carbide to activate peracetic acid to degrade carbamazepine; the mass fraction of the peracetic acid is 35%.

[0045] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One through Nine in that: defect-rich titanium carbide is used to activate peracetic acid to degrade carbamazepine, specifically by following these steps:

[0046] Defect-rich titanium carbide was added to a neutral aqueous solution containing carbamazepine and stirred for 3 to 5 minutes. Then peracetic acid was added and stirred for 5 to 40 minutes to obtain water after carbamazepine degradation.

[0047] The mass ratio of the defect-rich titanium carbide to the volume ratio of the aqueous solution containing carbamazepine is 30 mg: 100 mL.

[0048] The volume ratio of the peracetic acid to the aqueous solution containing carbamazepine is 0.05 mL: 100 mL.

[0049] The concentration of carbamazepine in the aqueous solution is 5 mg / L to 10 mg / L. Other steps are the same as in embodiments one through nine.

[0050] The beneficial effects of the present invention are verified using the following embodiments:

[0051] The instruments used in the following embodiments and experimental examples are: scanning electron microscope (manufacturer: Zeiss, Germany; model: Zeiss Gemini 300); fully automated X-ray diffractometer (manufacturer: Bruker D8 Advance, Germany); high performance liquid chromatograph (manufacturer: Shimadzu LC-16, Japan); centrifuge (manufacturer: Hexi Instrument Co., Ltd., China; model: H / T16MM); vacuum drying oven (manufacturer: Yiheng Instrument Co., Ltd., China; model: DZF-6051); online electrochemical workstation (manufacturer: Chenhua Instrument Co., Ltd., China; model: CHI 760E).

[0052] Example 1: A controllable preparation method for defect-rich titanium carbide, specifically carried out according to the following steps:

[0053] 1. Mix Ti3AlC2 and hydrofluoric acid solution evenly, then put it into a polytetrafluoroethylene bottle and stir in a constant temperature water bath at 40°C for 24 hours to obtain a mixed solution.

[0054] The hydrofluoric acid solution mentioned in step one has a mass fraction of 30%.

[0055] The mass ratio of Ti3AlC2 to hydrofluoric acid solution in step one is 4g:100mL;

[0056] 2. Pour the mixed solution into a centrifuge tube, centrifuge it in a centrifuge, and wash the mixed solution repeatedly with deionized water until the supernatant after centrifugation is neutral;

[0057] The centrifugation speed in step two is 6000 rpm, and the centrifugation time is 5 min / cycle;

[0058] 3. After centrifugation, the precipitate was collected and dried in a vacuum drying oven at 60°C for 24 hours, and then collected in a sealed bag to obtain multilayer Ti3C2T. x (BT);

[0059] IV. 2g of multilayer Ti3C2T x Mix 2g LiF and 40mL hydrochloric acid (concentration of 9mol / L) evenly, then place in a polytetrafluoroethylene bottle and react for a period of time to obtain the reaction product;

[0060] 5. Place the reaction product in a centrifuge tube, centrifuge it, and wash the reaction product repeatedly with deionized water until the supernatant after centrifugation is neutral. Collect the precipitate after centrifugation.

[0061] The centrifugation speed described in step five is 6000 rpm, and the centrifugation time is 5 min / cycle;

[0062] VI. The precipitate after centrifugation was added to oxygen-free deionized water and ultrasonically exfoliated in an ice bath under argon protection for a certain period of time to obtain the ultrasonically treated solution; the ice bath and argon protection conditions were to prevent the preparation of Ti3C2T x The nanosheets were oxidized;

[0063] The mass ratio of the precipitate after centrifugation to the volume ratio of deionized water in step six is ​​2g:100mL.

[0064] The ultrasound duration in step six is ​​1 hour, and the ultrasound power is 500W.

[0065] 7. Centrifuge the ultrasonically treated solution for a certain period of time to obtain the exfoliated few-layer Ti3C2T x Supernatant;

[0066] The centrifugation speed described in step seven is 3500 rpm, and the centrifugation time is 10 min;

[0067] 8. The use of fewer layers of Ti3C2T x Centrifuge the supernatant for a certain period of time and collect the precipitate after centrifugation.

[0068] The centrifugation speed in step eight is 12000 rpm, and the centrifugation time is 60 min;

[0069] 9. After centrifugation, the precipitate is freeze-dried for a certain period of time and collected in a sealed bag to obtain defect-rich titanium carbide, namely few-layer Ti3C2T. x (FT);

[0070] The freeze-drying temperature in step nine is -20°C, and the freeze-drying time is 36 hours.

[0071] Comparative Example 1: The raw material Ti3AlC2 from Example 1 was used as Comparative Example 1.

[0072] Figure 1 The multilayer Ti3C2T prepared in step three of Example 1 x SEM image of (BT);

[0073] from Figure 1 It can be seen that the prepared few-layer Ti3C2T x It exhibits a typical accordion-like morphology with a thin and loose layered structure; the blocky layered structure is destroyed, and irregular interlayer fracture marks appear on its surface.

[0074] Figure 2 The few-layer Ti3C2T prepared in step nine of Example 1 x (FT) TEM image;

[0075] from Figure 2 Few layers of Ti3C2T can be clearly observed. x The apparent thickness is approximately 1 nm, exhibiting a distinct monolayer of Ti3C2T. x Characteristics of nanosheets.

[0076] Figure 3 The Ti3AlC2 in Comparative Example 1 and the few-layer Ti3C2T prepared in step nine of Example 1 x (FT) Zeta potential plot;

[0077] Figure 4For the Ti3AlC2 in Comparative Example 1 and the multilayer Ti3C2T prepared in step three of Example 1 x (BT) and the few-layer Ti3C2T prepared in step nine of Example 1 x (FT) XRD pattern;

[0078] from Figure 4 It can be seen that: blocky Ti3C2T x It exhibits essentially the same diffraction peaks and intensities as unmodified Ti3AlC2. Few-layer Ti3C2T x The characteristic diffraction peak signals have basically disappeared, mainly because of the few-layer Ti3C2T x The interlayer spacing increases, resulting in a thin and loose layered structure, a phenomenon consistent with SEM observations.

[0079] Application Experiment:

[0080] Unmodified Ti3AlC2, multilayer Ti3C2T prepared in step three of Example 1 x (BT) and the few-layer Ti3C2T prepared in step nine of Example 1 x (FT) activation of PAA (peracetic acid) to degrade CBZ (carbamazepine) is carried out in the following steps:

[0081] Carbamazepine (CBZ) was selected as the target pollutant to evaluate the activation performance of the catalyst. The catalytic reaction system was carried out in 100 mL beakers at a constant temperature of 25°C in a magnetically stirred water bath. Under neutral initial pH conditions, 100 mL of CBZ aqueous solution (concentration 5 mg / L) was added to each beaker. After stirring at a constant temperature for 3 min to ensure uniformity of the pollutant and the system, 30 mg of unmodified Ti3AlC2 and multilayer Ti3C2T were added to each beaker, respectively. x (BT) and few-layer Ti3C2T x (FT) Two parallel experiments were conducted in each group. Stirring was continued for 3 minutes until the oxidant and the system were homogeneous. Then, 0.05 mL of 35% PAA was added to each beaker. Samples were taken using a 1 mL syringe at 3 min, 5 min, 10 min, 15 min, 25 min and 40 min after the addition of PAA. The samples were filtered through a 0.22 μm nylon 66 filter and mixed with excess sodium thiosulfate to terminate the reaction. Finally, high performance liquid chromatography analysis was performed.

[0082] The test results are as follows Figure 5 As shown, the unmodified Ti3AlC2 / PAA system exhibits approximately 3% removal rate of CBZ, indicating almost no degradation performance. The modified multilayer Ti3C2T... xThe (BT) activated PAA system could degrade approximately 38% of CBZ in the first 5 minutes, but the removal rate of CBZ remained almost unchanged thereafter, reaching only 40% degradation after 40 minutes. In the few-layer Ti3C2T... x In the (FT) / PAA system, the degradation rate of CBZ is relatively fast in the first 5 minutes, with approximately 70% of CBZ being degraded. At the end of the reaction, about 75% of the CBZ is degraded. This indicates that the few-layer Ti3C2T... x (FT) showed the best degradation effect on CBZ compared to unmodified Ti3AlC2 and multilayer Ti3C2T. x (BT), few-layer Ti3C2T x (FT) can expose more defect sites and active surfaces, thereby improving catalytic activity and better activating PAA.

Claims

1. Use of a titanium carbide rich in defects, characterized in that Defect-rich titanium carbide is used for activating peracetic acid to degrade carbamazepine; the mass fraction of the peracetic acid is 35%; The controllable preparation method of the defect-rich titanium carbide is specifically completed by the following steps: I. uniformly mix Ti3AlC2 and a hydrofluoric acid solution, then put into a polytetrafluoroethylene bottle, water-bath stir in a constant-temperature water bath for a certain time to obtain a mixed solution; II. pour the mixed solution into a centrifuge tube, centrifuge in a centrifuge, and repeatedly wash the mixed solution with deionized water until the supernatant after centrifugation is neutral; III. The precipitated material after centrifugation was placed in a vacuum drying oven and vacuum dried, and collected in a sealed bag to obtain multi-layer Ti3C2T x ; IV. The multilayer Ti3C2T x , LiF and hydrochloric acid were mixed uniformly, and then placed in a polytetrafluoroethylene bottle for reaction for a period of time to obtain a reaction product; V. put the reaction product into a centrifuge tube, centrifuge in a centrifuge, and repeatedly wash the reaction product with deionized water until the supernatant after centrifugation is neutral, and collect the precipitate after centrifugation; VI. add the precipitate after centrifugation to anaerobic deionized water and ultrasonically exfoliate in an argon-protected ice bath for a certain time to obtain an ultrasonically treated solution; Seven, the solution after ultrasonic treatment is centrifuged for a certain time to obtain the exfoliated few-layer Ti3C2T x supernatant; VIII. Exfoliating few-layer Ti3C2T x The supernatant was centrifuged for a certain time, and the precipitate after centrifugation was collected; IX. freeze-dry the precipitate after centrifugation for a certain time, and collect in a sealed bag to obtain the defect-rich titanium carbide.

2. Use of a defect-rich titanium carbide according to claim 1, characterized in that The mass fraction of the hydrofluoric acid solution in step I is 30%-70%; the mass of Ti3AlC2 to the volume of the hydrofluoric acid solution in step I is (2g-4g):(100mL-150mL); the temperature of water-bath stirring in step I is 40°C-60°C, and the time of water-bath stirring is 12h-24h.

3. Use of a defect-rich titanium carbide according to claim 1, characterized in that The speed of centrifugation in step II is 6000rpm-8000rpm, and the time of centrifugation is 3min / time-10min / time.

4. Use of a defect-rich titanium carbide according to claim 1, characterized in that The temperature of vacuum drying in step III is 60°C-80°C, and the time of vacuum drying is 24h-48h.

5. Use of a defect-rich titanium carbide according to claim 1, characterized in that The multilayer Ti3C2T x The mass-volume ratio of LiF and hydrochloric acid is (2g-4g):(2g-4g):(100mL-150mL); the concentration of the hydrochloric acid is 9mol / L-15mol / L; the temperature of the reaction in step four is 40℃-60℃, and the reaction time is 12h-24h.

6. Use of a defect-rich titanium carbide according to claim 1, characterized in that The speed of centrifugation in step V is 6000rpm-8000rpm, and the time of centrifugation is 3min / time-10min / time.

7. Use of a defect-rich titanium carbide according to claim 1, characterized in that The mass of the precipitate after centrifugation to the volume of the anaerobic deionized water in step VI is (2g-4g):(100mL-150mL); the time of ultrasonication in step VI is 1h-3h, and the power of ultrasonication is 250W-750W.

8. Use of a defect-rich titanium carbide according to claim 1, characterized in that The speed of centrifugation in step VII is 3500rpm-5000rpm, and the time of centrifugation is 10min-20min; the speed of centrifugation in step VIII is 12000rpm-15000rpm, and the time of centrifugation is 60min-100min; the temperature of freeze-drying in step IX is -10°C--50°C, and the time of freeze-drying is 36h-72h.

9. Use of a defect-rich titanium carbide according to claim 1, characterized in that Defect-rich titanium carbide is used for activating peracetic acid to degrade carbamazepine, which is specifically completed by the following steps: Add the defect-rich titanium carbide to a neutral aqueous solution containing carbamazepine, stir for 3min-5min, then add peracetic acid, stir for 5min-40min to obtain the aqueous solution after degradation of carbamazepine; The mass of the defect-rich titanium carbide to the volume of the aqueous solution containing carbamazepine is 30mg:100mL; The volume of the peracetic acid to the volume of the aqueous solution containing carbamazepine is 0.05mL:100mL; The concentration of carbamazepine in the aqueous solution containing carbamazepine is 5 mg / L to 10 mg / L.

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