A Ti3C2T x / / HEP catalysts, ozone composite catalytic packing materials, their preparation methods and applications

Abstract

This invention belongs to the field of wastewater treatment technology, specifically relating to a Ti3C2T x / / HEP catalyst, ozone composite catalytic packing material, its preparation method and application. The catalyst is composed of MXene sheet support and high-entropy perovskite oxide, and its preparation method is as follows: Ti3C2T x The metal salt is added to the solvent and stirred to obtain a mixture; then the ligand solution is added and stirred to form Ti3C2T. x / MOFs wet gel was dried under multi-gradient vacuum drying to obtain dry gel, which was then ground into powdered precursor; the precursor was calcined under an inert atmosphere and cooled to obtain Ti3C2T x / / HEP catalyst. The ozone composite catalytic packing material of this invention has advantages such as fast electron transfer rate, abundant active sites, high catalytic stability, and low metal leaching, and can be widely used in various industrial wastewaters for the degradation of organic matter.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a Ti3C2T x / / HEP catalyst, ozone composite catalytic packing material, its preparation method and application. Background Technology

[0002] Ozone catalytic oxidation technology has become the mainstream technology for the deep treatment of recalcitrant organic wastewater such as industrial park tailwater, landfill leachate, and membrane-concentrated wastewater due to its advantages such as strong oxidation capacity, fast reaction rate, and no secondary pollution. The core issue of this technology is the efficiency of electron transfer on the catalyst surface. By accelerating interfacial electron transfer, ozone activation can be enhanced to generate reactive oxygen species, thereby achieving efficient mineralization of organic matter.

[0003] Currently, conventional ozone catalysts generally suffer from key technological bottlenecks: the electron conduction capacity of traditional metal oxides, modified carbon materials, and other supports and active components is insufficient, resulting in low ozone activation efficiency and low free radical yield. Existing patented technologies have attempted to improve this, for example, patent CN109721148A discloses a heterojunction interface electron transfer ozone catalyst, which constructs a heterojunction using CeO2 and α-Fe2O3 composites, utilizing a bimetallic redox cycle to promote electron transfer and reduce bromate. However, this catalyst is still limited by insufficient active site density, resulting in high interfacial electron transfer impedance and limited ability to treat recalcitrant new organic pollutants.

[0004] Perovskite oxides, due to their tunable crystal structure and abundant surface oxygen vacancies, can enhance electron transfer efficiency to some extent. However, conventional single-component perovskites suffer from problems such as simple composition, poor lattice stability, and structural collapse, making it difficult to meet engineering requirements in terms of catalytic efficiency. For example, patent CN109607743A combines perovskite oxides with graphitic carbon nitride, utilizing the active sites and structural defects of perovskite to accelerate electron transfer. However, this structure has weak resistance to water quality interference, electrons are easily captured by impurities, interfacial conduction efficiency decays significantly, and long-term operational stability is insufficient.

[0005] In recent years, layered Ti3C2T x With its high conductivity, two-dimensional layered structure, abundant surface active sites, and structural stability, it has become an ideal electronic conduction framework material. Meanwhile, perovskite oxides (HEP) possess advantages such as multi-metal synergistic effects, significant lattice distortion, high oxygen vacancy concentration, and strong structural stability, making them a high-quality active component for efficient ozone activation. A search revealed that Ti3C2T... x There are no publicly reported ozone catalytic materials and technologies that construct continuous electron conduction interfaces by using an electron conduction framework and in-situ loading of active components. Summary of the Invention

[0006] To address the problems of slow electron migration, poor mass transfer efficiency, and low mineralization rate in existing ozone catalytic oxidation methods, a Ti3C2T core with an electron transport interface is proposed. x / / HEP composite ozone catalyst enables deep catalytic treatment of organic matter using ozone.

[0007] The specific technical solution of the present invention is as follows: The first objective of this invention is to provide a Ti3C2T x / / HEP catalyst, which is composed of MXene sheet support and high-entropy perovskite oxide, is prepared by the following steps: S1. Etching Ti3AlC2 with an etchant to obtain Ti3C2T with active ends. x ; S2, Ti3C2T x The metal salt is added to a solvent and stirred to obtain a mixture; the metal salt is a mixture of lanthanum, manganese, iron, cobalt, nickel and copper salts; S3. Add the ligand solution to the mixture and stir to form Ti3C2T x / MOFs wet gel was dried by multi-gradient vacuum drying to obtain dry gel, and then ground into powder precursor; S4. The precursor was calcined under an inert atmosphere and then naturally cooled to room temperature to obtain Ti3C2T. x / / HEP catalyst.

[0008] A further embodiment is the Ti3C2T with active terminals. x The preparation method is as follows: Ti3AlC2 was immersed in a mixed acid and sonicated, then reacted in an oil bath at 60–70 °C for 24–48 h. After cooling, the product was collected, washed, and dried to obtain Ti3C2T with active terminals. x .

[0009] In a further embodiment, the mixed acid is composed of hydrofluoric acid, nitric acid, and sulfuric acid, with a volume percentage of 90-95% hydrofluoric acid, 5-10% sulfuric acid, and the remainder being nitric acid.

[0010] In a further embodiment, in step S2, the concentration of metal ions in the mixture is 10–20 mmol / L, and Ti3C2T x The mass of the mixture accounts for 0.1% to 0.5% of the total mass of the mixture; and / or, The solvent is methanol, ethanol, or ethylene glycol.

[0011] In a further embodiment, the metal salt is La(NO3)3. 6H2O, Mn(NO3)2 4H2O, Fe(NO3)3 9H2O, Co(NO3)2 6H2O, Ni(NO3)2 6H2O and Cu(NO3)2 The molar ratio of each metal ion in 3H2O is 1:0.2:0.2:0.2:0.2:0.2.

[0012] In a further embodiment, the ligand solution is prepared by dissolving trimesic acid in an organic solvent, wherein the organic solvent is acetone, methanol, or ethanol; and the concentration of trimesic acid in the ligand solution is 0.3–0.4 mol / L.

[0013] A further embodiment of the proposed method is that the multi-gradient vacuum drying refers to drying under vacuum conditions at 40℃, 50℃, and 60℃ sequentially, with a total drying time of not less than 24 hours; and / or, The inert atmosphere is nitrogen or argon, and the calcination temperature is 500-800℃ for 2-4 hours.

[0014] The second objective of this invention is to provide an ozone composite catalytic packing material, which is composed of the aforementioned Ti3C2T x / / HEP catalyst, metal oxide and filler are used to prepare it, including Ti3C2T x / / The HEP catalyst accounts for 5-10% of the total mass.

[0015] In a further embodiment, the metal oxide is aluminum oxide, silicon oxide, or aluminum-silicon oxide, and its addition amount accounts for 7-9% of the total mass; and / or, The filler is sodium-based bentonite, calcium-based bentonite, or kaolin.

[0016] The third objective of this invention is to provide a method for preparing the above-mentioned ozone composite catalytic packing, which includes the following steps: Ti3C2T x / / HEP catalyst, metal oxide and filler are mixed in parts by mass and then calcined at high temperature to obtain ozone composite catalytic filler.

[0017] In a further embodiment, the high-temperature calcination temperature is 700–800℃ and the time is 2–4 hours.

[0018] The fourth objective of this invention is to provide an application of the aforementioned ozone composite catalytic packing material for ozone catalytic oxidation to remove organic matter from wastewater.

[0019] A further proposed approach is to add ozone composite catalytic packing material to the wastewater in the cyclone shear ozone reactor. After mixing ozone and wastewater into a mixture, it is added from the bottom jet of the cyclone shear ozone reactor; The stirrer is turned on to create a vortex, which shears ozone molecules into ozone micro-nano bubbles that spiral upward under the vortex, removing organic matter from the wastewater.

[0020] In a further embodiment, the mixture is formed by mixing ozone and wastewater from a cyclone shear ozone reactor, and then injected from the bottom of the cyclone shear ozone reactor via a jet pump to form a cycle; In the cyclone shear ozone reactor, the ozone flow rate is 100–300 mL / min, and the size of the ozone microbubbles is 10–100 nm; and / or, Based on the volume of wastewater treated, the dosage of ozone composite catalytic packing is 3–5 g / L, and the reaction time is 30–60 min; and / or, The cyclone shear ozone reactor includes a stirrer, the impeller of which has a titanium alloy spiral flow channel structure and the impeller speed is 100-200 r / min.

[0021] This invention constructs a high-density controllable oxygen vacancy by lattice distortion of high-entropy perovskite oxides; in which multiple metals synergistically regulate the catalytic active center, significantly reducing the ozone dissociation energy barrier, improving the efficiency of interfacial electron conduction and oxygen vacancy cycling, and greatly enhancing its catalytic activity.

[0022] This invention employs sol-gel in situ growth technology to grow HEP and Ti3C2T x A stable chemical bonding interface is formed between Ti and OM; and based on Ti3C2T x The two-dimensional layered conductive framework and the electron transport properties of MOFs construct a continuous, directional, and high-speed electron conduction pathway, significantly reducing the resistance to interfacial electron transfer and significantly enhancing ozone activation and free radical generation.

[0023] The Ti3C2T prepared by this invention x / / HEP catalyst is based on Ti3C2T x As a conductive framework, a continuous electron conduction channel is constructed at the heterogeneous interface, and high-entropy perovskite oxide (HEP) is loaded in situ on its surface as an ozone activation active component, which effectively reduces the interfacial electron transfer resistance and achieves high-efficiency ozone activation performance.

[0024] This invention utilizes a cyclone shear ozone reactor and micro / nano ozone oxidation technology, with Ti3C2T x / / HEP catalyst is used as the active ingredient to remove organic matter from wastewater, and it enhances Ti3C2T through cyclone shearing. x HEP interface electronic conduction has high application value for the treatment of recalcitrant organic matter in industrial wastewater.

[0025] This invention, starting from the essence of electron transport, constructs Ti3C2T x / / The HEP catalytic system reduces interfacial charge transfer resistance through continuous high-speed electron conduction channels. Combined with high-density oxygen vacancies and multi-metal active sites, it achieves a dual improvement in electron conduction efficiency and catalytic activity, providing a novel ozone catalytic technology route with high efficiency, stability, and low metal leaching for the deep treatment of recalcitrant organic wastewater.

[0026] The ozone composite catalytic packing prepared by this invention has advantages such as fast electron transfer rate, abundant active sites, high catalytic stability and low metal leaching. It can be widely used in the pretreatment of various industrial wastewaters and the deep treatment of recalcitrant organic wastewater such as reverse osmosis membrane concentrate, and has important engineering application value and scientific research significance. Attached Figure Description

[0027] Figure 1 It is the Ti3C2T prepared in Example 1 x / / Scanning electron microscope image of HEP catalyst; Figure 2 It is the Ti3C2T prepared in Example 1 x / / EDS diagram of HEP catalyst; Figure 3 It is the Ti3C2T prepared in Example 1 x / / Schematic diagram of the interfacial electron channels of the HEP catalyst; Figure 4 This is a structural diagram of a cyclone shear ozone reactor; Figure 5 Ti3C2T prepared in Example 1 x / / XRD comparison of HEP catalyst and HEP. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] The specific technical solution of the present invention is as follows: 1. Highly active Ti3C2T x Preparation Highly active Ti3C2T was prepared using a mixed acid etching method. x A mixed acid system consisting of 90-95% hydrofluoric acid, 5-10% sulfuric acid, and 1-2% nitric acid by volume; Ti3AlC2 was then immersed in a mixed acid and sonicated, followed by reaction in an oil bath at 60–70 °C for 24–48 h. After cooling, the product was collected, washed, and dried to obtain Ti3C2T with active terminals. x .

[0030] This etching method is highly efficient and operates under mild process conditions, yielding Ti3C2T. x The structure is more complete, the surface is less prone to defects, the active terminals are evenly distributed, and the interfacial bonding activity is high, which is conducive to efficient bonding with MOFs in the future, thus forming a stable electron conduction channel.

[0031] 2. Ti3C2T x MOFs Electron Conduction Interface Construction Lanthanum nitrate, manganese nitrate, ferric nitrate, cobalt nitrate, nickel nitrate, and copper nitrate were added to a solvent to prepare a multi-metal salt solution with a metal ion concentration of 10–20 mmol / L.

[0032] Tristyric acid was dissolved in an organic solvent to prepare a ligand solution containing 0.3–0.4 mol / L of tristyric acid.

[0033] Ti3C2T x Add 0.1–0.5% of the total mass of the mixture to the multi-metal salt solution, then add the ligand solution and mix and stir to generate Ti3C2T in situ. x / MOFs wet gel; vacuum drying was performed at multiple temperature gradients of 40℃, 50℃, and 60℃ to obtain dry gel, which was then ground into powdered precursor.

[0034] Through heterojunctions, electrostatic attraction, and multi-metal coordination coupling, in Ti3C2T x By constructing continuous, stable, and high-density high-speed electron conduction channels at the interface with multi-component MOFs, directional and rapid electron migration can be achieved (e.g., Figure 3 (As shown).

[0035] 3. Ti3C2T x / / HEP catalytic preparation The precursor was calcined at 500–800℃ for 2–4 hours under an inert atmosphere and then naturally cooled to obtain Ti3C2T. x / / HEP catalyst.

[0036] Among them, MOFs pyrolyze in Ti3C2T x In-situ surface formation creates a strong MO-Ti chemical bonding interface, inhibiting Ti3C2T x Clustering and Segregation. Ti3C2T x As a conductive framework, it significantly improves the conductivity and electron transport efficiency of HEP, enabling efficient ozone activation.

[0037] 4. Preparation of ozone composite catalytic packing material With Ti3C2T x / / HEP catalyst is the active component. After being mixed with metal oxides and fillers, it is then calcined at high temperature to obtain an ozone composite catalytic filler with high mechanical strength, good stability and low metal leaching.

[0038] The mass ratio of active components in ozone composite catalytic packing is 5-10%, the mass ratio of metal oxides is 7-9%, and the packing is the balance.

[0039] 5. Application of cyclone shear micro / nano ozone catalytic oxidation This invention employs a cyclone shear ozone reactor (such as...) Figure 4 To verify the ozone catalytic effect, an ozone-wastewater mixture was injected into the reactor from the outside using an ejector. The mixture was then stirred by an internal agitator. The impeller of the agitator broke the ozone molecules into micro-nano bubbles with a diameter of approximately 10–100 nm. These bubbles spiraled upwards under swirling currents, extending their residence time in the reactor by 3–5 times. This enhanced the contact and mass transfer between pollutants and active oxygen, thereby increasing the mineralization capacity of pollutants. This allows for the oxidative degradation of organic pollutants in various types of wastewater.

[0040] Based on the volume of wastewater, the dosage of ozone composite catalytic packing is 3-5 g / L.

[0041] Example 1: I. Preparation of Ti3C2T x / / HEP catalyst: S11. First, prepare 100 mL of mixed acid, in which the volumes of hydrofluoric acid, sulfuric acid, and nitric acid are 90 mL, 8 mL, and 2 mL, respectively.

[0042] 1 g of Ti3AlC2 was weighed and added to a mixed acid, and sonicated for 30 min. Then, it was transferred to a PTFE-lined reactor and heated in an oil bath at 60°C for 48 h. After cooling to room temperature, it was repeatedly washed with ethanol and pure water until the washing solution was neutral. The product was collected and dried to obtain MXene with active terminals. The highly active MXene surface contains a large number of hydroxyl groups, which can stably bind with perovskite components through covalent and hydrogen bonds.

[0043] S12, Weigh 0.1g of Ti3C2T x0.433g La(NO3)3·6H2O, 0.05g Mn(NO3)2·4H2O, 0.081g Fe(NO3)3·9H2O, 0.058g Co(NO3)2·6H2O, 0.058g Ni(NO3)2·6H2O, and 0.048g Cu(NO3)2·3H2O were added to 100mL of ethanol solution and stirred to obtain a mixed solution. S13. Weigh 6.3g of trimesic acid and dissolve it in 100mL of acetone to obtain a ligand solution; slowly introduce the ligand solution into the above mixture and stir rapidly to initially form Ti3C2T. x / MOFs wet gel. It was then placed in a vacuum drying oven and dried sequentially at multiple temperature gradients of 40, 50, and 60°C for 8 hours each to obtain dry gel. The dry gel was then ground into a powdered precursor. S14. The precursor is calcined under nitrogen protection at a temperature of 500℃ for 2 hours, and then naturally cooled to room temperature to obtain Ti3C2T. x / / High-entropy perovskite oxide, namely Ti3C2T x / / HEP catalyst.

[0044] The Ti3C2T prepared in this embodiment x / / Scanning electron microscope image of HEP catalyst as shown Figure 1 As shown in the figure, Ti3C2T x The HEP catalyst has a structure combining spherical and lamellar components, exhibiting an irregular shape. Specifically, it is a composite of a lamellar MXene sheet support and a spherical high-entropy perovskite oxide. This is further developed in Ti3C2T... x A heterojunction is formed at the HEP interface, providing interfacial electron channels, such as... Figure 3 As shown, the presence of interfacial electron channels can significantly improve the conductivity and electron transport efficiency of the catalyst, thereby achieving efficient ozone activation.

[0045] The Ti3C2T prepared in this embodiment x / / EDS diagram of HEP catalyst as shown Figure 2 As shown in the figure, the Ti3C2T x / / HEP catalyst contains the metal elements La and Mn 、 Fe 、 Co 、 Ni, Cu.

[0046] The Ti3C2T prepared in this embodiment x / / XRD comparison diagrams of HEP catalyst and HEP are shown below Figure 5 As shown in the figure. From the figure, we can see Ti3C2T x / / The peak of the HEP catalyst is narrower and shifted than the HEP peak alone, indicating that Ti3C2T x After being combined with HEP, the crystal structure of the material changed, and Ti3C2T appeared. x The peak.

[0047] The preparation method of HEP is the same as in Example 1, specifically as follows: Weigh out 0.1g of Ti3C2T x 0.433g La(NO3)3·6H2O, 0.05g Mn(NO3)2·4H2O, 0.081g Fe(NO3)3·9H2O, 0.058g Co(NO3)2·6H2O, 0.058g Ni(NO3)2·6H2O, and 0.048g Cu(NO3)2·3H2O were added to 100mL of ethanol solution and stirred to obtain a mixed solution. The above mixture was transferred to a hydrothermal high-pressure reactor made of polytetrafluoroethylene and reacted at 200°C for 10 hours. After cooling to room temperature, the precipitate was collected and repeatedly washed with deionized water and anhydrous ethanol. After drying, it was ground to 100 mesh to ensure sufficient heating during calcination, allowing the residual carbon precursor and nitrate ions to decompose thermally.

[0048] The ground product was placed in a muffle furnace and calcined under nitrogen protection at a temperature of 500°C for 2 hours. After natural cooling to room temperature, HEP (high entropy perovskite oxide) was obtained.

[0049] The above scanning electron microscope images are used to characterize the morphology of the material using scanning electron microscopy; The EDS image was obtained using an energy dispersive spectrometer. The XRD pattern was obtained using an X-ray diffractometer.

[0050] II. Preparation of ozone composite catalytic packing material: S21, Weigh 0.5g Ti3C2T x / / HEP catalyst, 8g alumina powder, and 1.5g sodium bentonite were mixed together; S22. The mixture is calcined at a high temperature of 700℃ for 2 hours to obtain ozone composite catalytic packing.

[0051] III. Ozone catalytic oxidation for the removal of organic matter from wastewater The structure of the cyclone shear ozone reactor in this application is as follows: Figure 4As shown, it includes a reactor 1, inside which a stirrer 2 is installed, and a jet pump 5. The outlet end of the jet pump 5 is connected to the bottom of the reactor 1, injecting a mixture of ozone and wastewater into the reactor 1. The inlet end of the jet pump 5 is connected to an ozone pipe 4 and a circulation pipe 3, respectively. The inlet of the circulation pipe 3 is connected to the upper part of the reactor 1, so that the wastewater in the reactor 1 is mixed with the ozone introduced by the ozone pipe 4 through the circulation pipe 3, and then injected into the reactor 1 from the bottom through the jet pump 5.

[0052] The processing procedure is as follows: S31. Add the wastewater to be treated into the cyclone shear ozone reactor, and then add ozone composite catalytic packing 6; the dosage of ozone composite catalytic packing is 3-5 g / L based on the volume of wastewater to be treated, and the reaction time is 30-60 min. S32. The wastewater from the upper layer of reactor 1 is discharged through the circulation pipe 3 and mixed with the ozone introduced by the ozone pipe 4 to form a mixture. Then, it is injected from the bottom of the reactor through the jet pump 5. S33. Turn on the agitator 2 to stir the wastewater to form a vortex. The impeller in the agitator 2 shears the ozone molecules into ozone micro-nano bubbles 7, which rise spirally under the vortex to remove organic matter from the wastewater.

[0053] The impeller of stirrer 2 is made of titanium alloy and has a spiral flow channel structure. The impeller in this application uses an existing structure, which performs knob shearing during rotation at a speed of 100–200 r / min. Stirring by stirrer 2 ensures that the injected mixture is uniformly mixed with the wastewater, with an ozone flow rate of 100–300 mL / min per liter of mixture. Simultaneously, the impeller breaks down ozone molecules into micro-nano-sized bubbles with a diameter of approximately 10–100 nm. These bubbles spiral upwards under swirling flow, extending their residence time in the reactor by 3–5 times. This enhances the contact and mass transfer between organic pollutants and active oxygen in the wastewater, strengthens the mineralization capacity of pollutants, and achieves the oxidative degradation of organic pollutants in the wastewater.

[0054] The wastewater treated in this embodiment is reverse osmosis concentrate from a zero-discharge wastewater system in a coal chemical plant. The concentrate has the following characteristics: COD 265 mg / L, TOC 195 mg / L, color 680 times, BOD 35 mg / L, TDS 25000 mg / L, and chloride ion concentration 12000–16000 mg / L. The recalcitrant organic matter in the reverse osmosis concentrate is a key factor affecting the salt separation efficiency of the downstream nanofiltration process, directly influencing the degree and properties of salts after evaporation and crystallization.

[0055] The above-mentioned ozone catalytic oxidation was used for treatment, wherein the dosage of ozone composite catalytic packing was 3 g / L based on the volume of wastewater to be treated, the reaction time was 30 min, the ozone flow rate in each liter of mixture was 100 mL / min, and the speed of stirrer 2 was 100 r / min.

[0056] After treatment, the COD in the effluent decreased to 55 mg / L, with a removal rate of 79.2%; TOC decreased to 18 mg / L, with a removal rate of 90.8%; and color decreased by 20 times, with a removal rate of 97.1%. These results demonstrate that under high salinity conditions, the ozone composite catalytic packing significantly improves the removal of organic matter from wastewater, indicating that the catalyst performance of this ozone composite catalytic packing is less affected by salinity.

[0057] The TDS concentration was tested using the 150℃ drying method, and the COD concentration was tested using the rapid digestion method.

[0058] Example 2: I. Preparation of Ti3C2T x / / HEP catalyst: S11. First, prepare 100 mL of mixed acid, in which the volumes of hydrofluoric acid, sulfuric acid, and nitric acid are 92 mL, 7 mL, and 1 mL, respectively.

[0059] 1 g of Ti3AlC2 was weighed and added to a mixed acid, and sonicated for 30 min. Then, it was transferred to a PTFE reactor liner and heated in an oil bath at 65°C for 24 h. After cooling to room temperature, it was repeatedly washed with ethanol and pure water until the washing solution was neutral. The product was collected and dried to obtain highly active MXene with a large number of hydroxyl groups on its surface.

[0060] S12, Weigh 0.2g of Ti3C2T x 0.325g La(NO3)3·6H2O, 0.038g Mn(NO3)2·4H2O, 0.062g Fe(NO3)3·9H2O, 0.044g Co(NO3)2·6H2O, 0.044g Ni(NO3)2·6H2O, and 0.036g Cu(NO3)2·3H2O were added to 100mL of ethylene glycol solution and stirred to obtain a mixed solution. S13. Weigh 7.35g of trimesic acid and dissolve it in 100mL of ethanol to obtain a ligand solution. Slowly introduce the ligand solution into the above mixture and stir rapidly to initially form Ti3C2T. x / MOFs wet gel. It was then placed in a vacuum drying oven and dried sequentially at multiple temperature gradients of 40, 50, and 60°C for 4 h, 8 h, and 12 h, respectively, to obtain dry gel. The dry gel was then ground into a powdered precursor. S14. The precursor was calcined under nitrogen protection at a temperature of 600℃ for 3 hours, and then naturally cooled to room temperature to obtain Ti3C2T. x / / HEP catalyst.

[0061] II. Preparation of ozone composite catalytic packing material: S21, Weigh 0.8g Ti3C2T x / / HEP, a mixture of 7.7g of alumina powder and 1.5g of calcium-based bentonite; S22. The mixture is calcined at a high temperature of 800℃ for 3 hours to obtain ozone composite catalytic packing.

[0062] III. Ozone catalytic oxidation for the removal of organic matter from wastewater The treatment method is the same as in Example 1, except that the dosage of the ozone composite catalytic packing material prepared in Example 2 is 4 g / L (based on the volume of wastewater being treated), and the reaction time is 40 min. The ozone flow rate in each liter of mixture is 200 mL / min, and the stirrer speed is 150 r / min.

[0063] The wastewater being treated is reverse osmosis concentrate from a pharmaceutical wastewater zero-discharge system. The raw water has the following characteristics: COD 450 mg / L, TOC 210 mg / L, BOD 50 mg / L, TDS 15000 mg / L, color 500 times, chloride ion concentration 5000 mg / L, and sulfate ion concentration 6000 mg / L. The recalcitrant organic matter in the concentrate is a key factor affecting the salt separation efficiency of the downstream nanofiltration process, directly influencing the degree and properties of salts after evaporation and crystallization.

[0064] After ozone catalytic oxidation treatment as described above, the COD in the effluent decreased to 50 mg / L, with a removal rate of 88.9%; TOC decreased to 15 mg / L, with a removal rate of 92.8%; and color decreased by 30 times, with a removal rate of 94.1%. Experiments show that the ozone composite catalytic packing material prepared in this embodiment has a significant effect on the removal of organic matter from high-salt wastewater.

[0065] Example 3: I. Preparation of Ti3C2T x / / HEP catalyst: S11. First, prepare 100 mL of mixed acid, in which the volumes of hydrofluoric acid, sulfuric acid, and nitric acid are 94 mL, 5 mL, and 1 mL, respectively.

[0066] 1 g of Ti3AlC2 was weighed and added to a mixed acid, and sonicated for 30 min. Then, it was transferred to a PTFE-lined reactor and heated in an oil bath at 70°C for 36 h. After cooling to room temperature, it was repeatedly washed with ethanol and pure water until the washing solution was neutral. The product was collected and dried to obtain MXene with active terminals. Its surface contains a large number of hydroxyl groups, which can stably bind with perovskite components through covalent and hydrogen bonds.

[0067] S12, Weigh 0.5g of Ti3C2T x 0.217g La(NO3)3·6H2O, 0.025g Mn(NO3)2·4H2O, 0.041g Fe(NO3)3·9H2O, 0.029g Co(NO3)2·6H2O, 0.029g Ni(NO3)2·6H2O, and 0.024g Cu(NO3)2·3H2O were added to 100mL of methanol solution and stirred to obtain a mixed solution. S13. Weigh 8.4 g of trimesic acid and dissolve it in 100 mL of acetone to obtain a ligand solution. Slowly introduce the ligand solution into the above mixture and stir rapidly to initially form Ti3C2T. x / MOFs wet gel. It was then placed in a vacuum drying oven and dried sequentially at multiple temperature gradients of 40, 50, and 60°C for 12 h, 8 h, and 4 h, respectively, to obtain dry gel. The dry gel was then ground into a powdered precursor. S14. The precursor was calcined under argon protection at a temperature of 800℃ for 4 hours to obtain Ti3C2T. x / / HEP catalyst.

[0068] II. Preparation of ozone composite catalytic packing material: S21, Weigh 1.0g Ti3C2T x / / HEP, 9g of alumina powder, and 1.0g of kaolin are mixed together; S22. The mixture is calcined at a high temperature of 800℃ for 2 hours to obtain ozone composite catalytic packing.

[0069] III. Ozone catalytic oxidation for the removal of organic matter from wastewater The treatment method is the same as in Example 1, except that the dosage of the ozone composite catalytic packing material prepared in Example 3 is 5 g / L (based on the volume of wastewater to be treated), and the reaction time is 60 min. The ozone flow rate in each liter of mixture is 300 mL / min, and the stirring speed is 200 r / min.

[0070] The wastewater being treated is the reverse osmosis concentrate from a zero-discharge system for dyeing and printing wastewater. The raw water has a COD of 185 mg / L, TOC of 115 mg / L, BOD of 28 mg / L, TDS of 8000 mg / L, and a color of 500 times. The recalcitrant organic matter in the concentrate is a key factor affecting the salt separation efficiency of the downstream nanofiltration process, directly influencing the degree and properties of salts after evaporation and crystallization.

[0071] After ozone catalytic oxidation treatment as described above, COD decreased to 32 mg / L, with a removal rate of 82.7%; TOC decreased to 21 mg / L, with a removal rate of 81.7%; and color decreased by 20 times, with a removal rate of 96%. The results show that the ozone composite catalytic packing prepared in this embodiment has a significant effect on removing organic matter from the reverse osmosis concentrate generated in the printing and dyeing industry.

[0072] Comparative Example 1: Traditional ozone catalyst 1: SAO3-II ozone catalyst from Guangzhou Sunny Environmental Protection Technology Co., Ltd., which is 3-5mm in diameter, gray-black spherical, and whose main active components are manganese, cerium and iron composite metal oxides, and whose support is modified active alumina / ceramsite.

[0073] Traditional ozone catalyst 2: Shandong Huatong Environmental Protection Technology Co., Ltd., with a length of 3-6mm, spherical structure, and light gray color.

[0074] The two conventional ozone catalysts mentioned above were used to treat the coal chemical wastewater in Example 1, and the same cyclone shear ozone reactor and operating conditions as in Example 1 were used.

[0075] Tests showed that the raw water had a COD of 265 mg / L and a TOC of 195 mg / L. After treatment with traditional ozone catalyst 1, the COD in the produced water was 105 mg / L and the TOC was 115 mg / L, resulting in a COD removal rate of 60.4% and a TOC removal rate of 40%. After treatment with traditional ozone catalyst 2, the COD in the produced water was 125 mg / L and the TOC was 155 mg / L, resulting in a COD removal rate of 52.8% and a TOC removal rate of 41.0%.

[0076] As can be seen from the above, the removal efficiency of existing traditional ozone catalysts for organic matter in wastewater is significantly lower than that in Example 1, indicating that the ozone composite catalytic packing prepared in this application contains Ti3C2T. x / / HEP significantly improves the conductivity and electron transport efficiency of HEP, enabling efficient ozone activation.

[0077] Comparative Example 2: The treatment method is the same as in Example 1, except that the reactor used in Comparative Example 2 is a common ozone reactor, which does not have a stirrer, so there is no stirring step in the treatment process.

[0078] The tests showed that the COD in the raw water was 265 mg / L and the TOC was 195 mg / L; the COD in the produced water was 155 mg / L and the TOC was 148 mg / L. Therefore, the COD removal rate was 41.5%, and the TOC removal rate was 24.1%. The removal efficiency for organic matter in the wastewater was significantly lower than that of Example 1, indicating that the cyclone shear reactor used in this application, with its agitator breaking down ozone molecules, is beneficial for improving the efficiency of ozone catalytic oxidation.

[0079] Comparative Example 3: The treatment method is the same as in Example 1, except that the active component of the ozone composite catalytic packing in Comparative Example 3 is the HEP active component, that is, step S11 is not included in the catalyst preparation steps, and Ti3C2T is not added in step S12. x .

[0080] Tests showed that the COD in the raw water was 265 mg / L and the TOC was 195 mg / L; the COD in the product water was 85 mg / L and the TOC was 65 mg / L. The average COD removal rate was 67.9%, and the average TOC removal rate was 66.6%. This indicates that the removal efficiency of Ti3C2T for organic matter in wastewater was significantly lower than in Example 1. This directly demonstrates the effectiveness of Ti3C2T in removing organic matter from wastewater. x / / The activity of the HEP catalyst is superior to that of HEP alone. The reason is that Ti3C2T x The combination with HEP forms an interfacial electronic channel, which is key to maintaining the high activity of the catalyst.

[0081] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A Ti3C2T x / / HEP catalyst, characterized in that: It is composed of MXene sheet support and high-entropy perovskite oxide, and its preparation method includes the following steps: S1. Etching Ti3AlC2 with an etchant to obtain Ti3C2T with active ends. x ; S2, Ti3C2T x The metal salt is added to a solvent and stirred to obtain a mixture; the metal salt is a mixture of lanthanum, manganese, iron, cobalt, nickel and copper salts; S3. Add the ligand solution to the mixture and stir to form Ti3C2T x / MOFs wet gel was dried by multi-gradient vacuum drying to obtain dry gel, and then ground into powder precursor; S4. The precursor was calcined under an inert atmosphere and then naturally cooled to room temperature to obtain Ti3C2T. x / / HEP catalyst.

2. A Ti3C2T according to claim 1 x / / HEP catalyst, characterized in that: The Ti3C2T with active ends x The preparation method is as follows: Ti3AlC2 was immersed in a mixed acid and sonicated, then reacted in an oil bath at 60–70 °C for 24–48 h. After cooling, the product was collected, washed, and dried to obtain Ti3C2T with active terminals. x .

3. A Ti3C2T according to claim 2 x / / HEP catalyst, characterized in that: The mixed acid is composed of hydrofluoric acid, nitric acid and sulfuric acid, with a volume percentage of 90-95% hydrofluoric acid, 5-10% sulfuric acid and the balance of nitric acid.

4. A Ti3C2T according to claim 1 x / / HEP catalyst, characterized in that: In step S2, the concentration of metal ions in the mixture is 10–20 mmol / L, and Ti3C2T x The mass of the mixture accounts for 0.1% to 0.5% of the total mass of the mixture; and / or, The solvent is methanol, ethanol, or ethylene glycol.

5. A Ti3C2T according to claim 1 x / / HEP catalyst, characterized in that: The metal salt is La(NO3)3 6H2O, Mn(NO3)2 4H2O, Fe(NO3)3 9H2O, Co(NO3)2 6H2O, Ni(NO3)2 6H2O and Cu(NO3)2 The molar ratio of each metal ion in 3H2O is 1:0.2:0.2:0.2:0.2:0.

2.

6. A Ti3C2T according to claim 1 x / / HEP catalyst, characterized in that: The ligand solution is prepared by dissolving pyromellitic acid in an organic solvent, wherein the organic solvent is acetone, methanol or ethanol; the concentration of pyromellitic acid in the ligand solution is 0.3 to 0.4 mol / L.

7. A Ti3C2T according to claim 1 x / / HEP catalyst, characterized in that: The multi-gradient vacuum drying refers to drying under vacuum conditions at 40℃, 50℃, and 60℃ sequentially, with a total drying time of not less than 24 hours; and / or, The inert atmosphere is nitrogen or argon, and the calcination temperature is 500-800℃ for 2-4 hours.

8. An ozone composite catalytic packing material, characterized in that: It is the Ti3C2T as described in any one of claims 1-7 x / / HEP catalyst, metal oxide and filler are used to prepare it, including Ti3C2T x / / The HEP catalyst accounts for 5-10% of the total mass.

9. The ozone composite catalytic packing material according to claim 8, characterized in that: The metal oxide is aluminum oxide, silicon oxide, or aluminum silicate oxide, and its addition amount accounts for 7-9% of the total mass; and / or, The filler is sodium-based bentonite, calcium-based bentonite, or kaolin.

10. The method for preparing an ozone composite catalytic packing material as described in claim 8, characterized in that: Includes the following steps: Ti3C2T x / / HEP catalyst, metal oxide and filler are mixed in parts by mass and then calcined at high temperature to obtain ozone composite catalytic filler.

11. The method for preparing an ozone composite catalytic packing material according to claim 10, characterized in that: The high-temperature calcination is carried out at a temperature of 700–800°C for 2–4 hours.

12. The application of the ozone composite catalytic packing material as described in claim 8, characterized in that: It is used for ozone catalytic oxidation to remove organic matter from wastewater.

13. The application of the ozone composite catalytic packing material according to claim 12, characterized in that: Ozone composite catalytic packing material is added to the wastewater in the cyclone shear ozone reactor; After mixing ozone and wastewater into a mixture, it is added from the bottom jet of the cyclone shear ozone reactor; The stirrer is turned on to create a vortex, which shears ozone molecules into ozone micro-nano bubbles that spiral upward under the vortex, removing organic matter from the wastewater.

14. The application of the ozone composite catalytic packing material according to claim 13, characterized in that: The mixture is made by mixing ozone and wastewater from a cyclone shear ozone reactor, and then injecting it from the bottom of the cyclone shear ozone reactor through a jet pump to form a cycle; In the cyclone shear ozone reactor, the ozone flow rate is 100–300 mL / min, and the size of the ozone microbubbles is 10–100 nm; and / or, Based on the volume of wastewater treated, the dosage of ozone composite catalytic packing is 3–5 g / L, and the reaction time is 30–60 min; and / or, The cyclone shear ozone reactor includes a stirrer, the impeller of which has a titanium alloy spiral flow channel structure and the impeller speed is 100-200 r / min.

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