Preparation method and application of high-performance water treatment material for continuous induction of limited fenton reaction

Abstract

This invention belongs to the field of water treatment catalytic membrane technology, and discloses a method for preparing and applying a high-performance water treatment material that utilizes confined space to continuously induce a Fenton-like reaction. By controlling the amount of FeCl3 and the reaction temperature, the single-atom Fe is controllably anchored at MXene Ti vacancies, and rapid self-assembly of the membrane material is achieved through vacuum filtration. The confined Fenton-like catalytic membrane utilizes the sub-nanometer confinement space to alter the hydrogen bond network of water molecules, making it difficult for them to dissociate, fundamentally inhibiting the hydrolysis and deactivation of Fe sites. This allows the Fenton-like reaction to maintain highly efficient and stable catalytic activity under both acidic and neutral conditions, breaking the strict dependence of the traditional Fenton reaction on acidic conditions. The efficient enrichment and directional mass transfer of ·OH in the confined layers improves the utilization rate of free radicals, enabling the catalytic membrane to exhibit excellent removal capabilities for organic pollutants. Furthermore, the size exclusion effect between the MXene layers effectively shields the interference of large molecular organic matter in the water.

Description

Technical Field

[0001] This invention belongs to the field of water treatment catalytic membrane technology, and relates to a method for preparing and applying a high-performance water treatment material that utilizes confined continuous induction of a Fenton-like reaction. Background Technology

[0002] Membrane separation technology has been widely used in water treatment due to its advantages such as simple operation, low energy consumption, and ease of large-scale integration. Combining catalytic oxidation with membrane separation technology to develop catalytic membrane materials that possess both pollutant retention and in-situ degradation capabilities has become an important development direction for advanced water treatment technologies. Among them, Fenton-like catalytic membranes have attracted widespread attention from researchers because they can utilize green oxidants such as H2O2 to generate highly reactive oxygen species in situ, achieving both high separation efficiency and thorough mineralization while simultaneously retaining and oxidizing organic pollutants. However, current Fenton-like catalytic membrane technology still faces several key bottlenecks: On the one hand, traditional iron-based Fenton-like catalytic membranes are severely limited by the pH dependence of the Fenton reaction. Their efficient catalytic oxidation process usually requires acidic conditions (pH 3.0–4.0), while actual water bodies are mostly near-neutral. Acidic conditions not only increase the cost of reagent addition but also easily cause membrane material corrosion and make equipment maintenance difficult. On the other hand, the catalytic active components in existing catalytic membranes are mostly loaded in the form of nanoparticles or clusters, resulting in poor dispersion of active sites, easy aggregation and loss, and a high risk of metal ion dissolution, which seriously restricts the long-term operational stability of the catalytic membrane. In view of this, developing a Fenton-like catalytic membrane that can operate efficiently and stably under near-neutral conditions and has atomically dispersed active components is of great significance for promoting the practical engineering application of this technology in the field of advanced water treatment.

[0003] To address the limitations of the aforementioned Fenton-like catalytic membranes, researchers have attempted to solve these problems by introducing external energy assistance. For example, Zhao et al., in "Photo-Fenton Degradation of Levofloxacin Wastewater by Composite Biochar under Near-Neutral Conditions," prepared a composite biochar catalyst by carbonizing a mixture of zero-valent iron-activated persulfate dewatered sludge and peat moss. Under xenon lamp irradiation (300W), they constructed a photo-Fenton system, achieving efficient degradation of levofloxacin under near-neutral conditions. Li et al., in "Local Acidic Microenvironment Construction via Alternating Current Electro-Fenton Process for Green Efficient Water Purification under Neutral Conditions," constructed an alternating current Fenton system, utilizing an electric field to drive the cycling of Fe species and create a locally acidic microenvironment in situ at the cathode, achieving efficient pollutant removal under neutral conditions. However, these photo-assisted or electro-assisted Fenton processes all require continuous energy input from external light sources or electric fields, increasing equipment investment and operating energy consumption. They also impose stringent requirements on reactor structural design and water quality conditions, hindering their large-scale application. Based on this, the present invention anchors Fe single atoms in the interlayer confinement environment of MXene nanosheets, and forms a confined Fenton-like catalytic membrane with an interlayer spacing of about 0.63 nm through filtration self-assembly. By utilizing the sub-nanometer confinement space to change the hydrogen bond network structure of water molecules, the hydrolysis of Fe sites can be inhibited. This enables efficient activation of H2O2 and deep removal of organic pollutants under neutral conditions without any external energy. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a high-performance water treatment material that utilizes confined space to continuously induce a Fenton-like reaction, wherein the prepared MXene-Fe SAC Nanosheets self-assemble through filtration to form a catalytic membrane with an interlayer spacing of approximately 0.63 nm, which can be loaded into a Fenton-like membrane reactor. By utilizing the confined space of MXenes to alter the hydrogen bond network of water molecules, Fe sites are protected from hydrolysis, thereby efficiently activating H2O2 to generate ·OH under neutral conditions. This technology can be applied to the deep removal and mineralization of organic pollutants in water.

[0005] The technical solution of this invention: A method for preparing a high-performance water treatment material that utilizes confined space to continuously induce a Fenton-like reaction includes the following steps: (1) After mixing Ti3AlC2 and ZnCl2 evenly, place them in a tube furnace and perform molten salt etching under an argon atmosphere to remove the Al layer and simultaneously introduce chlorine terminals and Ti vacancies; after natural cooling, wash with hydrochloric acid to remove residual ZnCl2 and Zn particles, wash repeatedly with distilled water until neutral, collect by centrifugation, freeze dry to obtain multilayer MXene powder rich in Ti vacancies; (2) FeCl3 powder and the multilayer MXene powder obtained in step (1) are placed in alumina crucibles upstream and downstream of a dual-temperature zone tube furnace, respectively. Under an argon atmosphere, the vapor generated by the sublimation of FeCl3 upstream is carried by the argon gas flow to the multilayer MXene powder downstream, where it is spontaneously captured by Ti vacancies and forms Fe-C and Fe-Cl coordination bonds. After being kept at the temperature for a certain period of time, it is naturally cooled to room temperature to obtain Fe single-atom anchored multilayer MXene (multilayer MXene-Fe). SAC ); (3) In an argon glove box, the multilayer MXene-Fe obtained in step (2) is placed... SAC LiCl was dispersed in anhydrous dimethyl sulfoxide and stirred for 24 hours to carry out Li + Intercalation; then washing with tetrahydrofuran and centrifuging to remove the supernatant; redispersing the precipitate in anhydrous N-methylformamide, repeating centrifugation and washing 2-3 times, and collecting the supernatant monolayer MXene-Fe SAC Nanosheet dispersion; the resulting monolayer MXene-Fe SAC The nanosheet dispersion was filtered under vacuum, utilizing the directional driving force of the filtration to allow the monolayer MXene-Fe to... SAC Nanosheets are tightly stacked and self-assembled into a membrane. The membrane layers are bonded by strong hydrogen bonds and van der Waals forces to form a stable self-supporting membrane structure, which is a confined Fenton-like catalytic membrane. It can be used as a high-performance water treatment material that utilizes confined space to continuously induce Fenton-like reactions.

[0006] Step (1): Ti3AlC2 and ZnCl2 are mixed at a mass ratio of 1:8. The temperature of molten salt etching is 550-850℃, the time is 3-5 hours, the heating rate is 5℃ / min, and the concentration of hydrochloric acid is 9-12M.

[0007] Step (2): Multilayer MXene powder and FeCl3 powder are mixed at a mass ratio of 1:(3-7). The upstream temperature of the dual-temperature zone tube furnace is 350-450℃, the downstream holding temperature is 400-500℃, and the holding time is 2 hours.

[0008] Step (3), multilayer MXene-Fe SAC The mass ratio of Li to LiCl is 3:1, Li + Intercalation time was 24 hours, centrifugation speed was 1500 rpm, monolayer MXene-Fe SACThe concentration of the nanosheet dispersion was 1.2 mg / mL, and vacuum filtration was used to form a film with a thickness of 100-500 nm and a film interlayer spacing of 0.63 nm.

[0009] The application of the above-mentioned confined Fenton-like catalytic membrane in the oxidative degradation of organic pollutants in water is carried out through the following steps: A confined Fenton-like catalytic membrane was loaded into a Fenton-like reactor. Under a pressure of 1.0–2.0 bar, water containing H2O2 and organic pollutants was filtered through the confined Fenton-like catalytic membrane via dead-end filtration. The controlled conditions were: atmospheric pressure, reaction temperature of 20–30 °C, and initial pH of the water of 3–7. The concentration of H2O2 in the reaction system was 1–3 mmol / L, and the hydraulic residence time was 7.4–18.6 ms. The enhanced effect of the hydrogen bond network of water molecules in the 0.63 nm sub-nanometer confined space between the membrane layers protected the Fe sites from hydrolysis. H2O2 was activated to generate ·OH without the need for external light, electricity, or heat, thus achieving efficient removal and mineralization of organic pollutants in the water.

[0010] The organic pollutant is benzoic acid (BA).

[0011] The working principle of this invention is as follows: A high-performance water treatment material utilizing confined space to continuously induce a Fenton-like reaction comprises a catalytic membrane formed by the self-assembly of multilayer MXene powder anchored by Fe single atoms through filtration, with an interlayer spacing of approximately 0.63 nm. When water molecules flow through this confined interlayer space, the hydrogen bond network of water molecules rearranges and is significantly strengthened due to the extreme spatial constraint. The proportion of water bound by strong hydrogen bonds increases from 35.3% to 67.3%, and the average hydrogen bond length of water molecules shortens from 1.84 Å to 1.26 Å, effectively suppressing the dissociation behavior of water molecules. This protects the Fe active sites from hydrolytic deactivation within the confined microenvironment between the membrane layers. Thanks to this protective mechanism, the preferential accessibility of Fe sites to H2O2 molecules is maintained, enabling continuous catalysis of the homolytic cleavage of H2O2 to produce ·OH within a neutral pH range without the need for external light, electricity, or heat. Meanwhile, the 0.63 nm confined channel significantly enhances the collision frequency and mass transfer efficiency between ·OH and the target pollutant, reducing the reaction time to as low as 7.4 ms, thereby achieving ultra-fast removal and deep mineralization of organic pollutants.

[0012] The beneficial effects of this invention are as follows: This invention provides a high-performance water treatment material that utilizes confined space to continuously induce a Fenton-like reaction. The preparation process of this Fe single-atom confined catalytic membrane is simple. Controllable anchoring of single-atom Fe on MXene Ti vacancies can be achieved by adjusting the amount of FeCl3 precursor and the reaction temperature, and rapid self-assembly of the membrane material is realized through vacuum filtration. Simultaneously, this confined catalytic membrane utilizes a 0.63 nm sub-nanometer confinement space to alter the hydrogen bond network of water molecules, making it difficult for them to dissociate. This fundamentally inhibits the hydrolysis and deactivation of Fe sites, enabling the Fenton-like reaction to maintain highly efficient and stable catalytic activity under both acidic and neutral conditions, breaking the strict dependence of the traditional Fenton reaction on acidic conditions. Furthermore, the efficient enrichment and directional mass transfer of ·OH within the confined layers greatly enhances the utilization rate of free radicals, resulting in excellent removal capabilities for organic pollutants. The size exclusion effect between the MXene layers effectively shields the interference of large molecular organic matter in the water, maintaining long-term stable operation even under complex water quality conditions. The above process requires no external energy input; it relies solely on the directional conversion of H2O2 chemical energy within a confined space to achieve efficient mineralization of organic pollutants. This is of great significance for promoting the practical engineering application of Fenton-like catalytic membrane technology in the field of advanced water treatment. Attached Figure Description

[0013] Figure 1 The MXene-Fe prepared in Example 1 and Comparative Example 1 of this invention SAC -1 Catalytic membrane and MXene-Fe SA Morphological characterization of nanosheets; where a is MXene-Fe SA Scanning electron microscope image of nanosheets; b represents MXene-Fe SAC -1 Scanning electron microscope image of the catalytic film; c is MXene-Fe SAC -1 Cross-sectional aberration electron microscope image of the catalytic membrane; d represents MXene-Fe SAC -1 Aberration-corrected electron micrograph of the surface of the catalytic film; Figure 2 yes Figure 6 MXene-Fe prepared in Example 1 SAC -1 XANES and EXAFS images of the catalytic film; where a represents MXene-Fe SAC -1 is the XANES diagram of the catalytic membrane, b is MXene-Fe SAC EXAFS image of the catalytic membrane -1; Figure 3 The MXene-Fe prepared in Examples 1, 2, 3 and Comparative Example 1 of this invention SAC -1, MXene-Fe SAC -2, MXene-Fe SAC -3 catalyst film and MXene-FeSAC The removal rate of BA by nanosheets activated by H2O2 degradation under neutral conditions; where a is MXene-Fe SAC -1, MXene-Fe SAC -2, MXene-Fe SAC -3 is the removal curve of BA by the catalytic membrane, b is MXene-Fe SAC Removal curves of BA by nanosheets; Figure 4 The MXene-Fe prepared in Example 1 and Comparative Example 1 of this invention SAC -1 Catalytic membrane and MXene-Fe SAC Electron paramagnetic resonance spectrum of H2O2 activated by nanosheets under neutral conditions; Figure 5 The MXene-Fe prepared in Example 1 and Comparative Example 1 of this invention SAC -1 Catalytic membrane and MXene-Fe SAC In-situ infrared analysis spectrum of iron species after nanosheet reaction; Figure 6 The MXene-Fe prepared by water molecules in Example 1 and Comparative Example 1 of this invention SAC -1 Catalytic membrane and MXene-Fe SAC Fitted in-situ infrared and in-situ Raman spectral analysis data of nanosheets; where a is the fitted in-situ infrared spectrum and b is the in-situ Raman spectrum; Figure 7 It is the MXene-Fe prepared in Example 1 of this invention. SAC -1. The performance of H2O2 treatment using a catalytic membrane to simulate actual wastewater. Here, a represents the removal curves of four representative organic pollutants in the wastewater, and b represents the performance of the membrane reactor during long-term operation. Detailed Implementation

[0014] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0015] Example 1 A method for preparing a high-performance water treatment material that utilizes confined space to continuously induce a Fenton-like reaction includes the following steps: (1) Ti3AlC2 (0.5 g) and ZnCl2 (4 g) were mixed evenly and placed in a tube furnace. Molten salt etching was performed under an ultra-high purity argon atmosphere at a temperature of 5 °C / min to 650 °C and held for 5 hours to remove the Al layer and simultaneously introduce chlorine terminals and Ti vacancies. After natural cooling, the residual ZnCl2 and Zn particles were removed by washing with 12M hydrochloric acid. The mixture was repeatedly washed with distilled water until neutral, collected by centrifugation, and freeze-dried to obtain multilayer MXene powder rich in Ti vacancies.

[0016] (2) FeCl3 powder (3.5 g) and the multilayer MXene powder (0.5 g) obtained in step (1) were placed in alumina crucibles upstream and downstream of a dual-temperature zone tube furnace, respectively. Under an argon atmosphere, the temperature was increased to 400℃ at 5℃ / min. The vapor generated by the sublimation of FeCl3 upstream was carried by the argon flow to the MXene nanosheets downstream, where it was spontaneously captured by Ti vacancies and formed Fe-C and Fe-Cl coordination bonds. After holding at this temperature for 2 hours, the mixture was naturally cooled to room temperature to obtain Fe single-atom anchored multilayer MXene (MXene-Fe). SAC ).

[0017] (3) In an argon glove box, the multilayer MXene-Fe obtained in step (2) is placed... SAC The powder and LiCl were dispersed in anhydrous dimethyl sulfoxide at a mass ratio of 3:1, and stirred for 24 hours to carry out LiCl precipitation. + Intercalation was performed; the precipitate was then washed with tetrahydrofuran and centrifuged at 1500 rpm for 5 minutes to remove the supernatant; the precipitate was redispersed in anhydrous N-methylformamide, and the centrifugation and washing were repeated 2-3 times to collect the supernatant monolayer MXene-Fe. SAC Nanosheet dispersion (concentration 1.2 mg / mL). The resulting dispersion was filtered under vacuum, utilizing the directional driving force of the filtration to... SAC Nanosheets are tightly stacked and self-assembled into a film. Strong hydrogen bonds and van der Waals forces bind the layers together to form a stable, self-supporting film structure, which is a confined Fenton-like catalytic membrane. The single-atom Fe in MXene accounts for 3.1%, denoted as MXene-Fe. SAC -1.

[0018] Furthermore, the aforementioned confined Fenton-like catalytic membrane was loaded into a Fenton-like reactor, with an effective area of ​​15.6 cm². 2 Driven by a pressure of 1.0~2.0 bar, the water containing H2O2 and organic pollutants is filtered through the membrane layer in a dead-end filtration manner. The controlled conditions are: atmospheric pressure, reaction temperature of 20~30℃, initial pH of wastewater of 3~7; concentration of H2O2 in the reaction system of 1~3 mmol / L, hydraulic residence time of 0~18.6 ms. The enhanced effect of the hydrogen bond network of water molecules in the 0.63 nm sub-nanometer confined space between the membrane layers is used to protect Fe sites from hydrolysis. H2O2 is activated to generate ·OH without the need for external light, electricity or heat energy, thereby achieving efficient removal and mineralization of organic pollutants in the water.

[0019] Example 2 The difference between this embodiment and specific embodiment 1 is that in step (2), the mass of the multilayer MXene powder and FeCl3 powder is controlled to be 0.5 g and 2.5 g, respectively, to obtain a catalyst material with a single-atom Fe content of 1.9% in MXene, denoted as MXene-Fe. SAC -2. Everything else is the same as in Specific Implementation Method 1.

[0020] Example 3 The difference between this embodiment and specific embodiment 1 is that in step (2), the multilayer MXene powder and FeCl3 powder are controlled at a mass of 0.5 g and 1.5 g, respectively, to obtain a catalytic material with a single-atom Fe content of 0.9% in MXene, denoted as MXene-Fe. SAC -3. Everything else is the same as in Specific Implementation Method 1.

[0021] Comparative Example 1 A method for preparing a high-performance water treatment material that utilizes confined space to continuously induce a Fenton-like reaction includes the following steps: The difference from specific embodiment 1 is that the MXene-Fe obtained in step (3) is... SAC The nanosheet dispersion was directly ultrasonically dispersed in 100 mL of a solution containing hydrogen peroxide (2 mM) and organic pollutants (0.05 mM) to control MXene-Fe SAC The amount of nanosheets used was the same as the mass of the membrane in Example 1. The control conditions were: normal pressure, reaction temperature of 20~30℃, initial pH of wastewater of 3~7; H2O2 concentration in the reaction system of 1~3 mmol / L; magnetic stirring reaction was carried out, and samples were taken at regular intervals to detect changes in pollutant concentration.

[0022] The invention was verified using the following experiments: Experiment 1: This experiment aims to test the application of catalytic membrane reaction systems in activating H2O2 to remove organic pollutants from water, comparing confined Fenton-like catalytic membranes (MXene-Fe) with different single-atom contents. SAC -1, MXene-Fe SAC -2 and MXene-Fe SAC-3) Removal effect on organic pollutants. A mixed solution containing BA (0.05 mM) and H2O2 (2 mM) was prepared using 100 mL of deionized water and filtered through a confined Fenton-like catalytic membrane at 25°C using a dead-end filtration method. The filtration reaction was carried out under a pressure of 1.0 bar, with a hydraulic residence time of 7.4 ms. Permeate was collected at different sampling times, filtered through a 0.22 μm PES polyethersulfone membrane, and 1 mL of the filtered sample was placed in a centrifuge tube. The reaction was terminated by adding 0.5 mL of 10 mmol / L sodium thiosulfate solution. The sample was stored at low temperature (4°C), and the concentration of benzoic acid at different sampling times was determined by high-performance liquid chromatography. The corresponding results are as follows: Figure 3 As shown in a. Simultaneously, a 5,5-dimethyl-1-pyrrolline-N-oxide (DMPO, >99%) solution was added to the extracted reaction solution as a spin trapping agent, bringing the final concentration of DMPO in the sample to 50 mM. After thorough mixing, the mixture was transferred to a quartz capillary tube, and the characteristic signal of the DMPO-·OH spin adduct was detected using electron paramagnetic resonance spectroscopy (EPR). The signal of ·OH in the EPR is shown in Figure a. Figure 4 As shown.

[0023] Experiment 2: This experiment is for detecting MXene-Fe SAC The degradation effect of nanosheet dispersion on benzoic acid in a batch reaction system. Unlike Experiment 1, MXene-Fe... SAC -1 The confined Fenton-like catalytic membrane was replaced with a monolayer MXene-Fe with the same mass as the membrane. SAC Nanosheet powder was processed in a batch reaction mode. Specifically, MXene-Fe... SAC Nanosheet powder was ultrasonically dispersed in a mixed solution containing benzoic acid (BA, 0.05 mM) and H₂O₂ (2 mM) prepared in 100 mL of deionized water. The reaction was carried out at 25 °C and 400 rpm with magnetic stirring. At different sampling times, 1 mL of the reaction solution was taken, filtered through a 0.22 μm PES polyethersulfone membrane, and the reaction was terminated by adding 0.5 mL of 10 mmol / L sodium thiosulfate solution. The samples were stored at low temperature (4 °C), and the concentration of benzoic acid at different sampling times was determined by high-performance liquid chromatography (HPLC). The corresponding results are as follows: Figure 3 As shown in b. Simultaneously, another portion of the reaction solution was added to DMPO solution to a final concentration of 50 mM for spin capture. After thorough mixing, the mixture was transferred to a quartz capillary tube, and the characteristic signal of the DMPO-·OH spin adduct was detected using EPR. The signal of ·OH in the EPR is shown in... Figure 4 As shown Figure 1 The MXene-Fe prepared in Example 1 and Comparative Example 1 of this invention SAC-1 Confined Fenton-like catalytic membrane and MXene-Fe SA Morphological characterization of nanosheets. Figure 1 The transmission electron microscopy image of MXene-Fe SA Monolayer morphology of nanosheets. Figure 1 The scanning electron microscope cross-sectional image of b in the image shows MXene-Fe self-assembled via vacuum filtration. SAC -1 confined Fenton-like catalytic membranes have a regular layered stacked structure and a membrane thickness of approximately 500 nm. Figure 1 The high-angle annular dark-field scanning transmission electron microscope image of c shows MXene-Fe SAC The interlayer spacing of the confined Fenton-like catalytic membrane is approximately 0.63 nm (6.3 Å), indicating that the filtration self-assembly forms a Fe-MXene catalytic membrane with regular sub-nanometer interlayer channels. Figure 1 The high-angle annular dark-field scanning transmission electron microscope image in the image clearly shows that Fe atoms are uniformly dispersed in the MXene lattice in the form of single atoms. Individual Fe atoms appear as uniformly distributed bright spots in the image, indicating that Fe atoms are successfully anchored at Ti vacancies in MXene.

[0024] Figure 2 MXene-Fe prepared in Example 1 SAC -1 XANES and EXAFS plots of a confined Fenton-like catalytic membrane. Figure 2 In Figure 'a', the XANES spectrum of Fe-MXene prepared in Example 1 is shown. XANES is used to study the electronic states of Fe atoms. The results show that the absorption edge of Fe-MXene is located between Fe foil and Fe3O4 / Fe2O3, indicating that the oxidation state of Fe species in Fe-MXene is intermediate between Fe... 0 and Fe 3+ between. Figure 2EXAFS measurements of b further confirmed the chemical structure of Fe atoms anchored on MXenes. No Fe-Fe bonds were detected near 2.2 Å in the Fe K-edge Fourier transform EXAFS of Fe-MXene (as present in the Fe foil EXAFS spectrum), ruling out the formation of Fe clusters or nanoparticles. A main peak at 1.97 Å, associated with the Fe-Cl bond configuration, was observed, along with a clear Fe-Cl signal at 2.43 Å. Quantitative EXAFS fitting showed that the first coordination shell of Fe is composed of Fe-C and Fe-Cl bonds, with coordination numbers of 3.11 and 1.12, and bond lengths of 1.97 Å and 2.43 Å, respectively, indicating that Fe atoms in Fe-MXene are anchored in the Ti vacancies of MXene with a Cl-Fe-C3 coordination configuration. These results clearly demonstrate that single-atom Fe is successfully anchored in MXene with Cl-Fe-C3 coordination. Figure 3 The MXene-Fe prepared in Examples 1, 2, 3 and Comparative Example 1 of this invention SAC -1, MXene-Fe SAC -2, MXene-Fe SAC -3 catalyst film and MXene-Fe SAC The removal rate of BA by H2O2 activated by nanosheets under neutral conditions. Figure 3 The results in section a show that as the Fe single-atom loading increased from 0.9% to 3.1%, the removal efficiency of BA increased sequentially. When the Fe loading was 3.1%, BA could be completely removed within a hydraulic residence time of 7.4 ms, and the reaction kinetic constant was as high as 605 s. -1 It exhibits a significant positive correlation between loading and activity. Figure 3 b represents the MXene-Fe prepared in Comparative Example 1. SAC The removal curves of BA degradation by Fe-MXene nanosheets under neutral conditions (pH=7) in batch reaction mode were presented. The results showed that the degradation efficiency of BA by Fe-MXene nanosheets in batch mode was extremely low; after 200 minutes of reaction, the BA removal rate was still less than 20%, indicating a near loss of catalytic activity. This suggests that the unconfined Fe sites rapidly hydrolyze and deactivate under neutral conditions. MXene-Fe SAC The pH activity of the catalytic membrane under neutral conditions originates from the regulatory effect of its 0.63 nm sub-nanometer confinement space on water molecules. When water molecules flow through this confined interlayer, the hydrogen bond network of water molecules rearranges and becomes significantly rigid due to extreme spatial constraint. This protects the Fe active sites from hydrolytic deactivation within the confined microenvironment, maintaining the preferential accessibility of Fe sites to H₂O₂ molecules. In batch mode, MXene-Fe… SACWhen nanosheets are exposed to water, the Fe sites cannot be protected by confined spaces, and under neutral conditions, Fe... 3+ It readily reacts with OH- - The combination forms ferric hydroxide or ferric oxide precipitates, leading to the deactivation of Fe sites and interruption of the Fenton cycle.

[0025] Figure 4 The MXene-Fe prepared in Example 1 and Comparative Example 1 of this invention SAC -1 Confined Fenton-like catalytic membrane and MXene-Fe SAC Electron paramagnetic resonance spectrum of H2O2 activated by nanosheets under neutral conditions, MXene-Fe SAC A strong ·OH radical signal peak was observed in the -1 catalytic membrane system. Meanwhile, MXene-Fe... SAC No signal was observed in the nanosheet catalytic system because the iron species were deactivated by hydroxylation under neutral conditions, and the Fenton cycle could not effectively catalyze the generation of free radicals from H2O2.

[0026] Figure 5 The MXene-Fe prepared in Example 1 and Comparative Example 1 of this invention SAC -1 Confined Fenton-like catalytic membrane and MXene-Fe SAC The evolution of iron species under in-situ infrared light after the nanosheets react under neutral conditions. (For MXene-Fe) SAC The catalytic film at -1 cm⁻¹ showed no significant change in surface functional groups throughout the reaction, except at 925 cm⁻¹. -1 A very weak Fe-OH bending vibration peak with a slight increase in intensity was observed, indicating that the conversion of Fe-Cl species to Fe-OH within the confined space was extremely low. However, for MXene-Fe... SAC Nanosheets, with Fe-Cl species on the surface continuously transforming to Fe-OH over time, 925 cm⁻¹ -1 The significantly enhanced intensity of the Fe-OH bending vibration peak indicates that the Fe sites, lacking confinement protection, undergo significant hydrolysis under neutral conditions. Simultaneously, the Fe-O / Fe-Cl lattice vibration peaks of FeOCl (400-550 cm⁻¹) are observed. -1 It is gradually destroyed during hydrolysis, 745 cm -1 (Out-of-plane bending) and 1020 cm -1 The enhanced Fe-OH bending vibration peak at the (in-plane bending) location over time corresponds to the formation of ferrimagnesian surface structures from FeOCl hydrolysis. The degree of Fe3O4 hydrolysis intensifies with increasing reaction time, and the surface hydroxyl groups (1055 cm⁻¹) increase. -1 Fe-OH bending vibration) and adsorbed water (1630 cm) -1 The vibrational peaks of the nearby H2O signal continuously increase. These results indicate that MXene-FeSAC The 0.63 nm sub-nanometer confinement space of the -1 catalytic film effectively suppressed the hydrolysis of Fe sites, while Fe-MXene nanosheets lacking confinement protection and traditional Fe-based catalysts both underwent significant hydrolysis and deactivation under neutral conditions.

[0027] Figure 6 The MXene-Fe prepared by water molecules in Example 1 and Comparative Example 1 of this invention SAC -1 Confined Fenton-like catalytic membrane and MXene-Fe SAC Fitted in-situ infrared and in-situ Raman spectral analysis data of nanosheets. Figure 6 The in-situ infrared spectrum of a is focused at 2800-3540 cm⁻¹. -1 The stretching vibrations of OH within the range were fitted to 3230, 3417, and 3552 cm. -1 The three characteristic peaks correspond to strong, moderate, and weak hydrogen bond interactions, respectively. Compared to bulk water, MXene-Fe SAC -1 The proportion of strongly hydrogen-bonded water molecules in the confined interlayer of the catalytic membrane increased significantly, indicating that the dissociation of water molecules within the confined space was suppressed. Figure 6 The in-situ Raman spectrum of b in the sample is between 3000 and 3750 cm⁻¹. -1 Three characteristic peaks were fitted within the OH stretching vibration range, corresponding to four-coordinate hydrogen-bonded water (4-HB·H₂O, strong hydrogen bond), two-coordinate hydrogen-bonded water (2-HB·H₂O, weak hydrogen bond), and free water, respectively. Compared with bulk water, the proportion of four-coordinate hydrogen-bonded water in the interlayer water molecules confined in the Fe-MXene catalytic film significantly increased from 35.3% to 67.3%, indicating that the interfacial water molecules in the confined space rearranged into a three-dimensional strong hydrogen bond network dominated by four-coordinate water, maximally restricting the dissociation of water molecules. In contrast, water in the unconfined MXene-Fe SAC The nanosheets lack confinement protection. The above results confirm that the 0.63 nm sub-nanometer confinement space effectively suppresses water dissociation through a rigid hydrogen bond network of water molecules, thereby protecting Fe sites from hydrolytic deactivation.

[0028] Figure 7 It is the MXene-Fe prepared in Example 1 of this invention. SAC -1 The confined Fenton-like catalytic membrane activation of H2O2 treatment simulates the performance of actual wastewater. Among them, Figure 7 'a' in MXene-Fe SAC-1 Removal curves of four representative organic pollutants in wastewater using a confined Fenton-like catalytic membrane. Typical phenolic organics from industrial and aquaculture wastewater—p-nitrophenol (NP); sulfanilamide antibiotics that promote drug resistance and threaten public health—sulfadimidine (SGD); carcinogenic chlorinated organics from chemical wastewater—pictalin (PIC); and fluorinated organics from electroplating and textile wastewater—2,4-difluorophenylacetic acid (DFPA) that can damage the human immune system—were selected as target pollutants. Under neutral conditions, phenolic and antibiotic pollutants were removed at a water flux not exceeding 10⁴ L / m³. -2 h -1 (Corresponding to a hydraulic retention time of 7.4 ms) 100% complete removal can be achieved. For chlorinated and fluorinated organic compounds, due to the extremely high bond energies of the C-Cl bond (bond energy ~397 kJ / mol) and CF bond (bond energy ~485 kJ / mol), they exhibit strong resistance to oxidation in the membrane Fenton system, with a water flux of 54~104 L m. -2 h -1 Complete removal is achieved within the range of hydraulic retention time (7.4~18.6 ms). Figure 7 In this context, 'b' represents the stability performance of the membrane reactor during long-term operation in treating simulated wastewater containing bisphenol A (BPA). Under simulated urban secondary effluent quality conditions, MXene-Fe SAC The -1 catalytic membrane, due to its size exclusion capability for background macromolecular organic matter, maintained stable removal of BPA for 15 days of continuous operation, achieving 100% complete removal in the first 5 days and maintaining a removal rate of over 90% after 15 days. After 15 days of reaction, the gradual accumulation of natural organic matter led to an increase in membrane resistance. When the operating pressure on the feed side exceeded 3.3 bar, the high pressure caused the membrane to rupture, disrupting the confined reaction space and consequently reducing reaction kinetics. These results demonstrate that the MXene-Fe developed in this invention... SAC -1 The catalytic membrane exhibits good long-term operational stability in actual wastewater treatment.

Claims

1. A method for preparing a high-performance water treatment material by confined continuous induction of a Fenton-like reaction, characterized in that, Includes the following steps: (1) After mixing Ti3AlC2 and ZnCl2 evenly, place them in a tube furnace and perform molten salt etching under an argon atmosphere to remove the Al layer and simultaneously introduce chlorine terminals and Ti vacancies; After natural cooling, the residual ZnCl2 and Zn particles were removed by washing with hydrochloric acid, and the mixture was repeatedly washed with distilled water until neutral. After centrifugation and freeze-drying, multilayer MXene powder rich in Ti vacancies was obtained. (2) Place the FeCl3 powder and the multilayer MXene powder obtained in step (1) into the alumina crucibles upstream and downstream of the dual-temperature zone tube furnace, respectively. Under an argon atmosphere, the vapor generated by the sublimation of FeCl3 upstream is carried by the argon gas flow to the downstream multilayer MXene powder, where it is spontaneously captured by Ti vacancies and forms Fe-C and Fe-Cl coordination bonds. After holding at this temperature for a certain period of time, it is naturally cooled to room temperature to obtain multilayer MXene anchored by a single Fe atom, which is multilayer MXene-Fe. SAC ; (3) In an argon glove box, the multilayer MXene-Fe obtained in step (2) is placed... SAC LiCl was dispersed in anhydrous dimethyl sulfoxide and stirred for 24 hours to carry out Li + Intercalation; then washing with tetrahydrofuran and centrifuging to remove the supernatant; The precipitate was redispersed in anhydrous N-methylformamide, and the mixture was centrifuged and washed 2–3 times. The upper monolayer MXene-Fe was collected. SAC Nanosheet dispersion; the resulting monolayer MXene-Fe SAC The nanosheet dispersion was filtered under vacuum, utilizing the directional driving force of the filtration to allow the monolayer MXene-Fe to... SAC Nanosheets are tightly stacked and self-assembled into a membrane. The membrane layers are bonded by strong hydrogen bonds and van der Waals forces to form a stable self-supporting membrane structure, which is a confined Fenton-like catalytic membrane. It can be used as a high-performance water treatment material that utilizes confined space to continuously induce Fenton-like reactions.

2. The method for preparing high-performance water treatment materials by confined continuous induction of Fenton-like reactions according to claim 1, characterized in that, Step (1): Ti3AlC2 and ZnCl2 are mixed at a mass ratio of 1:

8. The temperature of molten salt etching is 550-850℃, the time is 3-5 hours, the heating rate is 5℃ / min, and the concentration of hydrochloric acid is 9-12M.

3. The method for preparing high-performance water treatment materials by confined continuous induction of Fenton-like reactions according to claim 1, characterized in that, Step (2): Multilayer MXene powder and FeCl3 powder are mixed at a mass ratio of 1:(3-7). The upstream temperature of the dual-temperature zone tube furnace is 350-450℃, the downstream holding temperature is 400-500℃, and the holding time is 2 hours.

4. The method for preparing high-performance water treatment materials by confined continuous induction of Fenton-like reactions according to claim 1, characterized in that, Step (3), multilayer MXene-Fe SAC The mass ratio of Li to LiCl is 3:1, Li + Intercalation time was 24 hours, centrifugation speed was 1500 rpm, monolayer MXene-Fe SAC The concentration of the nanosheet dispersion was 1.2 mg / mL, and vacuum filtration was used to form a film with a thickness of 100-500 nm and a film interlayer spacing of 0.63 nm.

5. The high-performance water treatment material obtained by the preparation method according to any one of claims 1-4, which utilizes a confined, continuously induced Fenton-like reaction, is used as a confined Fenton-like catalytic membrane for the oxidative degradation of organic pollutants in water, characterized in that... The steps are as follows: A confined Fenton-like catalytic membrane was loaded into a Fenton-like reactor. Under a pressure of 1.0–2.0 bar, water containing H2O2 and organic pollutants was filtered through the confined Fenton-like catalytic membrane via dead-end filtration. The controlled conditions were: atmospheric pressure, reaction temperature of 20–30 °C, and initial pH of the water of 3–7. The concentration of H2O2 in the reaction system was 1–3 mmol / L, and the hydraulic residence time was 7.4–18.6 ms. The enhanced effect of the hydrogen bond network of water molecules in the 0.63 nm sub-nanometer confined space between the membrane layers protected the Fe sites from hydrolysis. H2O2 was activated to generate ·OH without the need for external light, electricity, or heat, thus achieving efficient removal and mineralization of organic pollutants in the water.

6. The application according to claim 5, characterized in that, The organic pollutant is benzoic acid.

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