A FeOCl / Ti3C2T x Chlorine-removing electrode material, preparation method and application thereof
By electrostatically self-assembling FeOCl/Ti3C2Tx materials, a flexible self-supporting film with microporous and mesoporous structures is formed, which solves the problems of low capacity, slow rate and poor stability of CDI electrode materials in the dechlorination process, and achieves efficient and low-cost dechlorination effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TONGJI UNIV
- Filing Date
- 2023-05-15
- Publication Date
- 2026-05-12
AI Technical Summary
Existing CDI electrode materials suffer from low capacity, slow rate, and poor cycle stability during dechlorination, especially traditional carbon materials and Faraday electrode materials, which perform poorly in applications.
Using FeOCl/Ti3C2Tx materials, a flexible self-supporting thin film with microporous and mesoporous structures is formed through electrostatic self-assembly. Combining the high theoretical Cl- storage capacity of FeOCl and the conductivity of Ti3C2Tx, it is used as a dechlorination electrode for seawater desalination and industrial wastewater treatment.
It achieves high dechlorination capacity, rapid dechlorination rate and low energy consumption, simplifies the preparation process, reduces costs, and has excellent mechanical properties and cycle stability.
Smart Images
Figure CN116553688B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of environmental materials technology, specifically relating to a FeOCl / Ti3C2T x Chlorine removal electrode materials, their preparation methods, and applications. Background Technology
[0002] Capacitive deionization (CDI) technology, as a promising electrochemical water treatment technology, boasts advantages such as energy saving, ease of operation, continuous operation, and long cycle life. The basic principle of CDI technology is to apply an external electric field, causing ions to move towards an electrode with the opposite charge, while simultaneously controlling the charging and discharging of the electrode to change the ion concentration at the electrode, thus achieving ion removal. Currently, most research on CDI electrode materials focuses on the design of cathode materials, while research on anode materials for chlorination removal is relatively limited.
[0003] Traditional dechlorination electrode materials for CDI (Chemical Dioxide) include activated carbon, carbon aerogels, and carbon nanotubes. However, carbon materials rely on an electric double-layer mechanism to store ions, resulting in low capacity and significant common-ion repulsion and side reactions, leading to low charge efficiency. With the rapid development of energy storage batteries in recent years, Faraday electrode materials have come into focus due to their higher adsorption capacity. Currently, Faraday dechlorination electrode materials mainly include Ag / AgCl and Bi / BiOCl. Ag / AgCl electrodes are expensive, and the conversion product AgCl has poor conductivity, resulting in a slow dechlorination rate. Bi / BiOCl electrodes undergo significant volume changes during charging and discharging, leading to poor cycle stability.
[0004] In summary, there is an urgent need to develop a new type of CDI dechlorination electrode with high dechlorination capacity, fast dechlorination rate, and excellent cycle performance. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the primary objective of this invention is to provide a FeOCl / Ti3C2T x For the first time, FeOCl's high Cl- content was utilized in the dechlorination electrode material. - Theoretical storage capacity, combined with two-dimensional layered Ti3C2T x Excellent electrical conductivity and film-forming properties allow for the formation of FeOCl / Ti3C2T composites with superior self-supporting capabilities through electrostatic self-assembly. x Chlorine removal electrode materials.
[0006] The second objective of this invention is to provide the above-mentioned FeOCl / Ti3C2T xThe preparation method of the dechlorination electrode material involves pyrolyzing FeCl3·6H2O to prepare FeOCl powder, washing it with acetone, and then suspending it in acetonitrile solution for ultrasonication. The precursor MAX phase (Ti3AlC2) is etched using HCl and LiF. After ultrasonic exfoliation of the etched product, monolayer or few-layer Ti3C2T is obtained. x Aqueous suspension, FeOCl acetonitrile suspension and Ti3C2T x The aqueous suspension is mixed, vacuum filtered, and then naturally dried to obtain the final product.
[0007] A third objective of this invention is to provide the above-mentioned FeOCl / Ti3C2T x The application of dechlorination electrode materials can be directly used as dechlorination electrodes in seawater desalination and industrial wastewater treatment, demonstrating advantages such as high dechlorination capacity, fast dechlorination rate and low energy consumption.
[0008] To achieve the above objectives, the present invention adopts the following technical solution:
[0009] This invention provides a FeOCl / Ti3C2T x The dechlorination electrode material is a flexible, self-supporting thin film material with microporous and mesoporous structures, produced by using Ti3C2T. x The two-dimensional sheet material is obtained by electrostatic self-assembly of FeOCl powder, wherein Ti3C2T x The surface of the two-dimensional sheet material is corrugated, and the cross-sections are stacked layer by layer.
[0010] Preferably, the FeOCl / Ti3C2T x The specific surface area of the dechlorination electrode material is 52.618 m². 2 / g.
[0011] This invention also provides the FeOCl / Ti3C2T x The preparation method of the dechlorination electrode material includes the following steps:
[0012] (1) Take FeCl3·6H2O and place it in a flat-bottomed, covered corundum crucible. Heat it in a muffle furnace to obtain FeOCl.
[0013] (2) Wash FeOCl with acetone by centrifugation and dry under vacuum;
[0014] (3) Mix LiF and HCl in a polytetrafluoroethylene reactor to obtain solution A;
[0015] (4) Add MAX-Ti3AlC2 to solution A, heat and stir in a water bath to obtain mixed solution B;
[0016] (5) Wash mixed solution B by centrifugation with HCl and collect precipitate A;
[0017] (6) After washing precipitate A with deionized water by centrifugation, water intercalation expansion treatment was repeatedly performed to collect precipitate B.
[0018] (7) Add ethanol to precipitate B, sonicate, centrifuge, and collect precipitate C;
[0019] (8) Add deionized water to precipitate C, shake well, sonicate, centrifuge, and collect the supernatant;
[0020] (9) Repeat step (8) to collect the liquid;
[0021] (10) Measure the concentration of the collected supernatant, dilute it, and obtain suspension A;
[0022] (11) Take FeOCl after vacuum drying in step (2), add acetonitrile, and sonicate to obtain suspension B;
[0023] (12) After mixing and stirring suspension A and suspension B, vacuum filter and dry to obtain FeOCl / Ti3C2T x Chlorine removal electrode materials.
[0024] Preferably, in step (1), the mass of FeCl3·6H2O is 1g, which is evenly spread on the bottom of a flat-bottomed corundum crucible with a lid that is 120mm long, 60mm wide and 18mm high. The muffle furnace is heated at a rate of 5℃ / min to 220℃ and held for 3h.
[0025] Preferably, in step (2), the washing is performed until the washing liquid is colorless.
[0026] Preferably, in step (3), the mass of LiF is 2g, the concentration of HCl is 9mol / L, the volume is 40mL, the volume of the polytetrafluoroethylene reactor is 100mL, the stirring time is 30min, and the stirring speed is 400rpm.
[0027] Preferably, in step (4), the amount of MAX-Ti3AlC2 added is 2g, the water bath heating temperature is 35℃, and the stirring time is 24h.
[0028] Preferably, in step (5), the HCl concentration is 1 mol / L and the washing is performed 4 times.
[0029] Preferably, in step (6), the centrifugation speed is 3500 rpm, the duration of each centrifugation is 10 min, the number of washing cycles is not less than 10, and the pH value of the washing solution is not less than 6.
[0030] Preferably, in step (6), the water intercalation expansion treatment is performed as follows: add deionized water to the precipitate, mix with a vortex shaker, centrifuge, do not pour out the supernatant, mix again, centrifuge, repeat the process at least 20 times until the precipitate shows obvious expansion.
[0031] Preferably, in step (7), the amount of ethanol added is 40 mL, the ultrasonic time is 1 h, the ultrasonic conditions are argon atmosphere, ice bath, centrifugation speed is 10000 rpm, and the duration is 10 min.
[0032] Preferably, in step (8), the amount of deionized water added is 20 mL, the ultrasonic time is 20 min, the ultrasonic conditions are argon atmosphere, ice bath, centrifugation speed is 3500 rpm, and the duration is 5 min.
[0033] Preferably, in step (10), the concentration of the supernatant is determined by taking 5 mL of supernatant, filtering it, drying it naturally, weighing the membrane, and calculating the concentration.
[0034] Preferably, in step (10), the concentration of suspension A is diluted to 0.5 mg / mL according to the measured concentration.
[0035] Preferably, in step (11), the mass of FeOCl is 10 mg, the volume of acetonitrile is 20 mL, and the ultrasonic time is 30 min.
[0036] Preferably, in step (12), the volume of suspension A is 40 mL, the mixing and stirring time of suspension A and suspension B is 5 min, a polyvinylidene fluoride filtration membrane with a pore size of 0.22 μm is used, and the drying condition is natural drying.
[0037] This invention also provides the FeOCl / Ti3C2T x Application of dechlorination electrode materials as anode materials in capacitive deionization dechlorination processes.
[0038] Due to the adoption of the above solution, the beneficial effects of the present invention are:
[0039] I. FeOCl has strong dechlorination potential, but existing research has only combined it with organic solvent systems for application in chloride ion batteries. This invention is the first to apply FeOCl as a dechlorination electrode material in the field of water treatment.
[0040] II. During the mixed film extraction process, FeOCl acts as an interlayer pillar, effectively mitigating the stress on the two-dimensional nanosheets Ti3C2T. x Due to the self-stacking phenomenon that easily occurs due to van der Waals forces, Cl is further improved. - Interlayer storage capacity.
[0041] III. MXene-Ti3C2Tx It possesses good electrical conductivity, being FeOCl / Ti3C2T. x Constructing a good conductive network is beneficial for the rapid transport of chloride ions during the dechlorination process, thus increasing the dechlorination rate.
[0042] IV. The FeOCl / Ti3C2T of the present invention x The dechlorination electrode material can form a film by a simple filtration process, and has excellent mechanical properties. It can be used directly as a dechlorination electrode for CDI without the need for conventional binders and conductive agents. This avoids cumbersome operations such as slurry preparation and coating. The preparation method is simple to operate, low in cost, and has great practical industrial production value. Attached Figure Description
[0043] Figure 1 The image shows the X-ray diffraction pattern of pure FeOCl powder in Comparative Example 1.
[0044] Figure 2 FeOCl / Ti3C2T in Example 1 x Dechlorination electrode material and pure Ti3C2T in Comparative Example 2 x Scanning electron microscope images of the thin film surface and cross-section.
[0045] Figure 3 FeOCl / Ti3C2T in Example 1 x The dechlorination electrode material, pure FeOCl powder in Comparative Example 1, and pure Ti3C2T in Comparative Example 2 x Specific surface area of a thin film.
[0046] Figure 4 FeOCl / Ti3C2T in Example 1 x The dechlorination electrode material, pure FeOCl powder in Comparative Example 1, and pure Ti3C2T in Comparative Example 2 x Nitrogen adsorption / desorption curves of the thin film.
[0047] Figure 5 FeOCl / Ti3C2T in Example 1 x The dechlorination electrode material, pure FeOCl powder in Comparative Example 1, and pure Ti3C2T in Comparative Example 2 x Pore size distribution of the thin film.
[0048] Figure 6 FeOCl / Ti3C2T in Example 1 x Optical images showcasing the toughness of the thin film used in the dechlorination electrode material.
[0049] Figure 7 FeOCl / Ti3C2T in Example 1 xThe dechlorination capacity and dechlorination rate of the dechlorination electrode material thin film under different current densities. Detailed Implementation
[0050] The present invention will be further described below with reference to embodiments and comparative examples.
[0051] FeOCl / Ti3C2T was prepared in the following examples. x The preparation method of the dechlorination electrode material includes the following steps:
[0052] (1) Take FeCl3·6H2O and place it in a flat-bottomed, covered corundum crucible. Heat it in a muffle furnace to obtain FeOCl.
[0053] (2) Wash FeOCl with acetone by centrifugation and dry under vacuum;
[0054] (3) Mix LiF and HCl in a polytetrafluoroethylene reactor to obtain solution A;
[0055] (4) Add MAX-Ti3AlC2 to solution A, heat and stir in a water bath to obtain mixed solution B;
[0056] (5) Wash the mixed solution B by centrifugation with HCl and collect the precipitate A;
[0057] (6) After washing precipitate A by centrifugation with deionized water a certain number of times, repeatedly perform water intercalation expansion treatment and collect precipitate B.
[0058] (7) Add ethanol to precipitate B, sonicate, and centrifuge to collect precipitate C;
[0059] (8) Add deionized water to precipitate C, shake well, sonicate, and centrifuge to collect the supernatant;
[0060] (9) Repeat step (8) to collect as much of the supernatant as possible;
[0061] (10) Measure the concentration of the collected supernatant, dilute it, and obtain suspension A;
[0062] (11) Take FeOCl, add acetonitrile, and sonicate to obtain suspension B;
[0063] (12) After mixing and stirring suspension A and suspension B, vacuum filter and dry to obtain FeOCl / Ti3C2T x Chlorine removal electrode materials.
[0064] In step (1), FeCl3·6H2O undergoes the following pyrolysis reaction: FeCl3+H2O→FeOCl+2HCl to generate FeOCl. The mass of FeCl3·6H2O is 1g, which is evenly spread on the bottom of a flat-bottomed corundum crucible with a lid that is 120mm long, 60mm wide, and 18mm high. The muffle furnace is heated at a rate of 5℃ / min until it reaches 220℃, and then held for 3h.
[0065] In step (2), since the Zeta potential of the FeOCl suspension is positive, while that of Ti3C2T is negative... x The suspension has a negative Zeta potential. During mixing, stirring, and vacuum filtration, the two components undergo spontaneous electrostatic self-assembly, forming FeOCl / Ti3C2T. x It has a good pore structure and ion transport channels, which creates favorable conditions for the subsequent dechlorination process; the washing number is until the washing liquid is colorless.
[0066] In step (3), the mass of LiF is 2g, the concentration of HCl is 9mol / L, the volume is 40mL, the volume of the polytetrafluoroethylene reactor is 100mL, the stirring time is 30min, and the stirring speed is 400rpm.
[0067] In step (4), the amount of MAX-Ti3AlC2 added is 2g, the water bath heating temperature is 35℃, and the stirring time is 24h.
[0068] In step (5), the HCl concentration is 1 mol / L, and the washing is performed 4 times.
[0069] In step (6), the centrifugation speed is 3500 rpm, the duration of each centrifugation is 10 min, the number of washing cycles is not less than 10, and the pH value of the washing solution is not less than 6.
[0070] In step (6), the water intercalation expansion treatment is performed as follows: add deionized water to the precipitate, mix with a vortex shaker, centrifuge, do not pour out the supernatant, mix again, centrifuge, repeat the process at least 20 times until the precipitate shows obvious expansion.
[0071] In step (7), the amount of ethanol added is 40 mL, the ultrasonic time is 1 h, the ultrasonic conditions are argon atmosphere, ice bath, centrifugation speed is 10000 rpm, and the duration is 10 min.
[0072] In step (8), the amount of deionized water added is 20 mL, the ultrasonic time is 20 min, the ultrasonic conditions are argon atmosphere, ice bath, centrifugation speed is 3500 rpm, and the duration is 5 min.
[0073] In step (10), the method for determining the concentration of the supernatant is as follows: take 5 mL of supernatant, filter it, dry it naturally, weigh the mass of the membrane, and calculate the concentration of the supernatant.
[0074] In step (10), the concentration of suspension A is diluted to 0.5 mg / mL according to the measured concentration.
[0075] In step (11), the mass of FeOCl is 10 mg, the volume of acetonitrile is 20 mL, and the ultrasonic time is 30 min.
[0076] In step (12), the volume of suspension A is 40 mL, the mixing time of suspension A and suspension B is 5 min, a polyvinylidene fluoride filtration membrane with a pore size of 0.22 μm is used, and the drying condition is natural drying.
[0077] The FeOCl / Ti3C2T prepared by the above method x The dechlorination electrode material is used as the anode material in capacitive deionization technology in electrochemical dechlorination.
[0078] Example 1
[0079] This embodiment prepares FeOCl / Ti3C2T x The steps for removing chlorine from electrode materials are as follows:
[0080] (1) Take 1g of FeCl3·6H2O and spread it evenly on the bottom of a flat-bottomed corundum crucible with a lid that is 120mm long, 60mm wide and 18mm high. Place it in a muffle furnace and heat it. Set the heating rate of the muffle furnace to 5℃ / min, raise it to 220℃, and keep it for 3h to obtain FeOCl powder.
[0081] (2) Wash the FeOCl powder with acetone by centrifugation until the washing liquid is colorless, and then dry it under vacuum.
[0082] (3) Take 2g of LiF and 40mL of 9mol / L HCl and mix them in a 100mL polytetrafluoroethylene reactor for 30min at a speed of 400rpm to obtain solution A.
[0083] (4) Add 2g of MAX-Ti3AlC2 to solution A, heat and stir in a water bath at 35℃ for 24h to obtain mixed solution B.
[0084] (5) Wash the mixed solution B four times by centrifugation with HCl at a concentration of 1 mol / L, and collect the precipitate A.
[0085] (6) Wash precipitate A by centrifugation with deionized water at 3500 rpm for 10 min each time, and repeat at least 10 times. The pH of the washing solution should not be lower than 6. Then add deionized water to the precipitate, mix with a vortex mixer, centrifuge, do not discard the supernatant, mix again, centrifuge, repeat at least 20 times until the precipitate shows obvious swelling, and finally collect precipitate B.
[0086] (7) Add 40 mL of ethanol to precipitate B, sonicate for 1 h under argon atmosphere and ice bath conditions, and then centrifuge continuously at 10000 rpm for 10 min to collect precipitate C.
[0087] (8) Add 20 mL of deionized water to precipitate C, shake well, sonicate for 20 min under argon atmosphere and ice bath conditions, and then collect the supernatant by continuous centrifugation at 3500 rpm for 5 min.
[0088] (9) Repeat step (8) to collect as much of the supernatant as possible.
[0089] (10) Take 5 mL of the supernatant, filter it, dry it naturally, weigh the membrane, and calculate the concentration of the supernatant. Dilute the supernatant to a concentration of 0.5 mg / mL according to the measured concentration to obtain suspension A.
[0090] (11) Take 10 mg FeOCl, add 20 mL acetonitrile, and sonicate for 30 min to obtain suspension B.
[0091] (12) Take 40 mL of suspension A and mix it with 20 mL of suspension B above. Stir for 5 min, then perform vacuum filtration using a polyvinylidene fluoride membrane with a pore size of 0.22 μm. After natural drying, obtain FeOCl / Ti3C2T x Chlorine removal electrode materials.
[0092] Comparative Example 1
[0093] The steps for preparing pure FeOCl powder in this comparative example are as follows:
[0094] (1) Take 1g of FeCl3·6H2O and spread it evenly on the bottom of a flat-bottomed corundum crucible with a lid that is 120mm long, 60mm wide and 18mm high. Place it in a muffle furnace and heat it. Set the heating rate of the muffle furnace to 5℃ / min, raise it to 220℃, and keep it for 3h to obtain FeOCl.
[0095] (2) FeOCl was washed with acetone by centrifugation until the washing solution was colorless, and then vacuum dried to obtain pure FeOCl powder sample.
[0096] Comparative Example 2
[0097] This comparative example prepared pure Ti3C2Tx Thin film, the steps are as follows:
[0098] (1) Take 2g of LiF and 40mL of 9mol / L HCl and mix them in a 100mL polytetrafluoroethylene reactor for 30min at a speed of 400rpm to obtain solution A.
[0099] (2) Add 2g of MAX-Ti3AlC2 to solution A, heat and stir in a water bath at 35℃ for 24h to obtain mixed solution B.
[0100] (3) Wash the mixed solution B four times by centrifugation with HCl at a concentration of 1 mol / L, and collect the precipitate A.
[0101] (4) Wash precipitate A by centrifugation with deionized water at 3500 rpm for 10 min each time, and repeat at least 10 times. The pH of the washing solution should not be lower than 6. Then add deionized water to the precipitate, mix with a vortex mixer, centrifuge, do not discard the supernatant, mix again, centrifuge, repeat at least 20 times until the precipitate shows obvious swelling, and finally collect precipitate B.
[0102] (5) Add 40 mL of ethanol to precipitate B, sonicate for 1 h under argon atmosphere and ice bath conditions, and then centrifuge continuously at 10000 rpm for 10 min to collect precipitate C.
[0103] (6) Add 20 mL of deionized water to precipitate C, shake well, sonicate for 20 min under argon atmosphere and ice bath conditions, and then collect the supernatant by continuous centrifugation at 3500 rpm for 5 min.
[0104] (7) Repeat step (8) to collect as much of the supernatant as possible.
[0105] (8) Take 5 mL of the supernatant, filter it, dry it naturally, weigh the membrane, and calculate the concentration of the supernatant. Dilute the supernatant to a concentration of 0.5 mg / mL according to the measured concentration to obtain suspension A.
[0106] (9) Take 40 mL of suspension A, perform vacuum filtration using a polyvinylidene fluoride membrane with a pore size of 0.22 μm, and allow it to dry naturally to obtain pure Ti3C2T. x film.
[0107] The products of the above embodiments and comparative examples were subjected to the following experiments.
[0108] Experiment 1
[0109] The purpose of this experiment was to characterize the crystal structure of the prepared pure FeOCl powder (Comparative Example 1). The X-ray diffraction (XRD) test results of the pure FeOCl powder are as follows: Figure 1 As shown, obvious diffraction peaks appeared at 2θ = 11.05°, 26.03°, 35.45°, 38.10°, 48.10°, 50.37°, 56.03°, 60.89° and 76.81°, respectively, corresponding to the (010), (110), (021), (111), (200), (131), (002), (022) and (202) crystal planes of FeOCl, which are consistent with the standard card PDF#24-1005, indicating that the sample prepared by the above method has the crystal structure of FeOCl.
[0110] Experiment 2
[0111] The purpose of this experiment was to characterize the dechlorination electrode material FeOCl / Ti3C2T prepared in Example 1. x Pure Ti3C2T was prepared in Comparative Example 2. x The microstructure of the thin film was examined using scanning electron microscopy (SEM) on the FeOCl / Ti3C2T dechlorination electrode material prepared in Example 1. x Pure Ti3C2T was prepared in Comparative Example 2. x The surface of the thin film ( Figure 2 (above) and cross section ( Figure 2 The results of the shooting are as follows (below) Figure 2 As shown, the pure Ti3C2T prepared... x The film surface exhibits a corrugated pattern, and the cross-section shows a stacked layer structure, proving that the two-dimensional sheet material Ti3C2T... x Successful etching. The FeOCl / Ti3C2T structure formed after electrostatic self-assembly with FeOCl. x The surface developed more and finer wrinkles, resulting in a denser cross-section. These fine wrinkles increase the accessibility of chloride ions, thus promoting ion diffusion. The denser cross-section is likely due to the interaction of FeOCl and Ti3C2T. x More micropores are formed during electrostatic self-assembly, creating more ion storage sites.
[0112] Experiment 3
[0113] The purpose of this experiment was to characterize the FeOCl / Ti3C2T prepared in Example 1, Comparative Example 1, and Comparative Example 2. x Pure FeOCl powder and pure Ti3C2T x Specific surface area and pore size distribution of the thin film.
[0114] Figure 3 The BET specific surface area obtained from the above three samples is FeOCl / Ti3C2T. x The maximum specific surface area is 52.618 m². 2 / g, pure FeOCl powder and pure Ti3C2T x The thin films are 10.576 μm thick. 2 / g and 3.6806m 2 / g.
[0115] Figure 4 The above are the nitrogen adsorption / desorption curves obtained from the tests on the three samples, including FeOCl / Ti3C2T. x It exhibits rapid adsorption in the low-pressure region and shows obvious hysteresis loops, which are characteristic of micropores and mesopores, respectively.
[0116] Figure 5 The figure shows the pore size distribution based on the BJH model. It can be seen from the figure that FeOCl / Ti3C2T x Having more than pure FeOCl powder and pure Ti3C2T x The thin film has more micropores (<2 nm) and mesopores (2–50 nm), resulting in the largest specific surface area, which corresponds to the nitrogen adsorption / desorption curve results. This is due to the presence of FeOCl and Ti3C2T... x The electrostatic self-assembly process forms a rich porous structure, thus FeOCl / Ti3C2T x When used as a dechlorination electrode material in CDI, the microporous structure can provide multiple adsorption sites for ion accommodation, thereby improving the dechlorination capacity, while the mesoporous structure can establish pathways to accelerate ion diffusion and promote ion transport, thereby improving the dechlorination rate.
[0117] Experiment 4
[0118] The purpose of this experiment was to characterize the dechlorination electrode material FeOCl / Ti3C2T prepared in Example 1. x Mechanical properties.
[0119] FeOCl / Ti3C2T x Optical images of dechlorination electrode materials, such as Figure 6 As shown, the prepared FeOCl / Ti3C2T x The dechlorination electrode material is a flexible, self-supporting thin film with good mechanical strength, and can be bent. Figure 6 (Left), and it has good toughness, so it can be cut into any shape. Figure 6 (Right). The above shows that the FeOCl / Ti3C2T prepared by this invention... x The membrane can be used directly as a dechlorination electrode; two-dimensional Ti3C2T xNanosheets possess excellent self-contained film properties, functioning as both a chlorine removal material and a conductive agent and binder for FeOCl, eliminating the need for conventional electrode preparation processes that require powdered binders and conductive agents such as polyvinylidene fluoride and carbon black. These additives are expensive, and subsequent slurry preparation and coating operations are extremely cumbersome. Nanosheets significantly reduce production costs, shorten production time, and simplify the process.
[0120] Experiment 5
[0121] The purpose of this experiment was to test the FeOCl / Ti3C2T electrode material used for dechlorination in Example 1. x The dechlorination capacity and dechlorination rate of CDI. At a NaCl concentration of 1000 mg / L. -1 FeOCl / Ti3C2T prepared in Example 1 under a cutoff voltage of 1.2V x The dechlorination capacity and dechlorination rate of dechlorination electrode materials at different current densities are as follows: Figure 7 As shown, FeOCl / Ti3C2T x The dechlorination capacity decreases with increasing current density, while the dechlorination rate shows the opposite trend. This is because at higher current densities, chloride ions migrate faster, and the CDI system reaches the cutoff voltage more quickly, thus leading to the reduction of chloride ion concentration in the FeOCl / Ti3C2T system. x The dechlorination capacity decreases while the dechlorination rate increases. FeOCl / Ti3C2T x The chlorine removal capacity reaches its maximum of 76.75 ± 2.89 mg at a current density of 50 mA / g. Cl - / g Anode At 100 mA / g, the chlorine removal rate can reach 1.90 ± 0.15 mg. Cl - / g Anode / min.
[0122] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. A FeOCl / Ti3C2T x The dechlorination electrode material is characterized by, It is a flexible self-supporting thin film material with microporous and mesoporous structure, which is prepared by Ti3C2T x The two-dimensional sheet material is electrostatically self-assembled with FeOCl powder, wherein the Ti3C2T x The surface of the two-dimensional sheet material is corrugated, and the cross section is stacked layer by layer; The FeOCl / Ti3C2T x The preparation method of the dechlorination electrode material includes the following steps: (1) Take FeCl3·6H2O and place it in a flat-bottomed corundum crucible with a lid. Heat it in a muffle furnace to obtain FeOCl powder. (2) Wash the FeOCl powder with acetone by centrifugation and then dry it under vacuum; (3) Mix LiF and HCl in a polytetrafluoroethylene reactor and stir to obtain solution A; (4) Add MAX-Ti3AlC2 to solution A, heat and stir in a water bath to obtain mixed solution B; (5) The mixed solution B was washed by centrifugation with HCl, and the precipitate A was collected; (6) After washing precipitate A with deionized water by centrifugation, it was repeatedly subjected to water intercalation expansion treatment, and precipitate B was collected. (7) Add ethanol to precipitate B, sonicate, centrifuge, and collect precipitate C; (8) Add deionized water to precipitate C, shake well, sonicate, centrifuge, and collect the supernatant; (9) Repeat step (8) to collect the supernatant; (10) Measure the concentration of the collected supernatant, dilute it, and obtain suspension A; (11) Take FeOCl after vacuum drying in step (2), add acetonitrile, and sonicate to obtain suspension B; (12) After mixing and stirring suspension A and suspension B, vacuum filtration and drying were performed to obtain FeOCl / Ti3C2T x Chlorine removal electrode materials.
2. The FeOCl / Ti3C2T according to claim 1 x The dechlorination electrode material is characterized by, The FeOCl / Ti3C2T x The specific surface area of the dechlorination electrode material is 52.618 m². 2 / g.
3. The FeOCl / Ti3C2T according to claim 1 x The dechlorination electrode material is characterized by, In step (1), the mass of FeCl3·6H2O is 1 g, which is evenly spread on the bottom of a flat-bottomed corundum crucible with a lid that is 120 mm long, 60 mm wide and 18 mm high. The muffle furnace is heated at a rate of 5 ℃ / min to 220 ℃ and held for 3 h. And / or in step (2), wash until the washing solution is colorless; And / or in step (3), the mass of LiF is 2 g, the concentration of HCl is 9 mol / L, the volume is 40 mL, the volume of the polytetrafluoroethylene reactor is 100 mL, the stirring time is 30 min, and the rotation speed is 400 rpm; And / or in step (4), the amount of MAX-Ti3AlC2 added is 2 g, the water bath heating temperature is 35℃, and the stirring time is 24 h; And / or in step (5), the HCl concentration is 1 mol / L and the number of washes is 4; In step (6), the centrifugation speed is 3500 rpm, the duration of each centrifugation is 10 min, the number of washing cycles is not less than 10, and the pH value of the washing solution is not less than 6.
4. The FeOCl / Ti3C2T according to claim 1 x The dechlorination electrode material is characterized by, In step (6), the water intercalation expansion treatment includes: adding deionized water to the precipitate, mixing with a vortex mixer, centrifuging, without discarding the supernatant, mixing again, centrifuging, repeating the process at least 20 times until the precipitate shows expansion.
5. The FeOCl / Ti3C2T according to claim 1 x The dechlorination electrode material is characterized by, In step (7), the amount of ethanol added is 40 mL, the ultrasonic time is 1 h, the ultrasonic conditions are argon atmosphere, ice bath, centrifugation speed is 10000 rpm, and the duration is 10 min.
6. The FeOCl / Ti3C2T according to claim 1 x The dechlorination electrode material is characterized by, In step (8), the amount of deionized water added is 20 mL, the ultrasonic time is 20 min, the ultrasonic conditions are argon atmosphere, ice bath, centrifugation speed is 3500 rpm, and the duration is 5 min.
7. The FeOCl / Ti3C2T according to claim 1 x The dechlorination electrode material is characterized by, In step (10), the method for determining the concentration of the supernatant is as follows: take 5 mL of supernatant, filter, dry naturally, weigh the mass of the membrane, calculate the concentration of the supernatant, and dilute it to a concentration of 0.5 mg / mL in suspension A according to the measured supernatant concentration.
8. The FeOCl / Ti3C2T according to claim 1 x The dechlorination electrode material is characterized by, In step (11), the mass of FeOCl is 10 mg, the volume of acetonitrile is 20 mL, and the ultrasonic time is 30 min; In step (12), the volume of suspension A is measured to be 40 mL, the mixing time of suspension A and suspension B is 5 min, a polyvinylidene fluoride filtration membrane with a pore size of 0.22 μm is used, and the drying condition is natural drying.
9. The FeOCl / Ti3C2T according to any one of claims 1 to 8 x Application of dechlorination electrode materials as anode materials in capacitive deionization dechlorination processes.