Preparation of monolithic catalyst from waste lithium-manganese battery and its preparation method and application

Abstract

The application discloses a method for preparing a monolithic catalyst by using waste lithium manganate batteries and application thereof. The method is characterized in that after the waste lithium manganate batteries are disassembled, the positive pole piece is obtained by a pretreatment-subsection stripping process to obtain defective manganese nanoparticles, then the defective manganese nanoparticles are obtained by selectively recovering lithium and mixed weak acid etching, and finally, the oxygen vacancy-defective manganese-based-powder / monolithic catalyst is prepared, which can be used for catalytic oxidation of VOCs or simultaneous catalytic removal of NO x and VOCs in low and medium temperature (200-300 DEG C) flue gas. The application can prepare a low-cost composite catalyst while selectively recovering lithium, and the prepared catalyst has high catalytic activity, high resistance (resistance to nitrogen oxides, resistance to sulfur, resistance to ammonia, resistance to water), a wide active temperature range and high catalytic selectivity, and can be widely applied in the fields of NO x and VOCs and other atmospheric pollutant control.

Description

TECHNICAL FIELD

[0001] The present application belongs to the cross field of solid waste treatment and resource utilization and environmental catalysis technology, and particularly relates to a preparation method of a composite monolithic catalyst and application thereof in solid waste treatment and air environmental pollution treatment. BACKGROUND

[0002] Lithium ion battery is one of the key supporting technologies of clean energy, and the global lithium battery shipment shows an explosive rapid growth trend. At present, the recycling technologies mainly based on pyrometallurgical and hydrometallurgical processes are complex, high in environmental pollution, low in efficiency and high in cost. Due to the unique structural characteristics and charge transport mechanism, battery materials are beneficial to the efficient transport of gas, ion and electron at the single / multi-phase interface. The previous experiments also observed that the Lewis basic center at the interface of the battery material can catalyze the generation of gaseous products such as CO2 and methanol, which shows that the unique structure and interface enhancement effect of the battery material may have unique advantages in catalytic oxidation reaction.

[0003] Since the industrial revolution, fossil fuels have been the main energy source for human beings, but oil, petrochemical products, coal and the like will emit a large amount of gaseous pollutants such as nitrogen oxides (NO x ) and volatile organic compounds (VOCs) during use or combustion, which is an important challenge to achieve "carbon reduction and pollution reduction". Through catalytic removal of VOCs, including simultaneous catalytic removal of NO x and VOCs in a denitration facility, it is a reasonable choice in terms of technology and economy in the field of air environmental pollution treatment. The key to catalytic removal is to prepare a composite monolithic catalyst which is cheap, easy to obtain, high in activity and stability.

[0004] In view of this, the present application proposes a classification recycling and "waste-to-resource" strategy in view of the problems existing in the field of solid waste treatment and air environmental pollution treatment, and high-value lithium and transition metals in waste lithium manganate lithium battery cathode materials are classified and recycled. After the waste lithium manganate lithium battery is disassembled, the positive electrode sheet is obtained by a pretreatment-subsection stripping process to obtain defect type manganese nanoparticles, and then the lithium is selectively recovered and etched by mixed acid to obtain oxygen vacancy-defect type manganese nanoparticles, so as to prepare an oxygen vacancy-defect type manganese-based-powder / monolithic catalyst. The catalyst can be used for catalytic oxidation of VOCs or simultaneous catalytic removal of NO x and VOC in low-temperature (200-300 DEG C) flue gas. At the same time, the catalyst widens the catalytic activity temperature window, and shows high catalytic activity, high resistance, wide activity temperature range and high catalytic selectivity.

[0005] The present application provides a new idea and direction for the preparation of a composite monolithic catalyst in the field of solid waste treatment and air environmental pollution treatment. SUMMARY

[0006] The application aims to classify and recycle high-value lithium in waste lithium manganate cathode materials to prepare oxygen vacancy-defect type manganese-based-powder / monolithic catalysts, which can catalyze the removal of VOCs and also can catalyze the removal of NO x and VOCs, and provides a simple preparation method of a catalyst for solid waste treatment and atmospheric environmental pollution treatment and application thereof. The application can prepare a low-cost composite catalyst while selectively recovering lithium, and the prepared catalyst has high catalytic activity, high resistance (resistance to nitrogen oxides, resistance to sulfur, resistance to ammonia, resistance to water), a wide active temperature range and high catalytic selectivity, and can be widely applied to the fields of NO x and VOCs and other atmospheric pollutants control.

[0007] The application achieves the above-mentioned purpose through the following technical solutions.

[0008] A catalyst for catalytic oxidation of VOCs and simultaneous catalytic removal of NO x and VOCs in flue gas and a preparation method thereof, after disassembling waste lithium manganate batteries, the positive electrode sheet is subjected to pretreatment and a segmented stripping process to obtain acid-etched defect type manganese nanoparticles, then the lithium is selectively recovered and mixed acid etching to obtain oxygen vacancy-defect type manganese nanoparticles, finally, the composite binder is added to load on the cordierite carrier to prepare the oxygen vacancy-defect type manganese-based-powder / monolithic catalyst for catalytic oxidation of VOCs and simultaneous catalytic removal of NO x and VOCs in flue gas.

[0009] The above-mentioned method specifically includes the following steps.

[0010] (1) Preparation of weak acid etching-defect type manganese nanoparticle precursor:

[0011] The waste lithium manganate batteries are subjected to deactivation, disassembly, crushing and component separation steps for pretreatment, and the positive electrode material, copper foil, aluminum foil, carbon powder and plastic film are separated, the positive electrode sheet is placed in mixed acid, subjected to constant temperature ultrasonic immersion, dried, placed in a tube furnace for segmented calcination, ground and sieved to obtain defect type manganese nanoparticles, which are ready for use; the mixed acid includes one or more of acetic acid, oxalic acid and citric acid; the atmosphere of the tube furnace is nitrogen, argon, high-purity nitrogen or nitrogen with an oxygen content of 5-90 vol%;

[0012] (2) Selective recovery of lithium and preparation of oxygen vacancy-defect type manganese nanoparticles:

[0013] The organic acid is mixed with deionized water, placed in a rotary evaporator, and stirred at a constant temperature to dissolve it. The oxygen vacancy-defect type manganese nanoparticles prepared in step (1) are added, and after ultrasonic treatment, the mixture is continuously stirred at a constant temperature. After standing, the upper liquid is poured out. After adding deionized water and immersing, the upper liquid is poured out. The Li is recovered by multiple cycles. After recovering the Li, the lower slurry is dried, ground, and calcined in stages to obtain the oxygen vacancy-defect type manganese nanoparticle / powder catalyst. The organic acid includes one or more of acetic acid, oxalic acid, and citric acid.

[0014] (3) Preparation of the oxygen vacancy-defect type manganese-based monolithic catalyst:

[0015] The coptite is soaked in mixed acid for 2-6 h, washed with distilled water until the pH of the washing liquid is neutral, then dried at a temperature of 110-180°C for 4-8 h, and transferred to a muffle furnace for calcination at a temperature of 350-750°C for 3-8 h to remove adsorbed impurities. The composite powder catalyst prepared in step (2) is ball milled in a ball mill, mixed with acid, and placed in a rotary evaporator for constant temperature stirring to dissolve it. One or two of silica sol, pseudoboehmite, and hydroxy cellulose are added, the pH is adjusted, and a stable slurry is formed after stirring. The coptite block is ultrasonically immersed in the slurry to load it, then the residual suspension is blown off to form a uniform film on the surface of the substrate. The film is dried and the immersion process is repeated until the appropriate loading amount is reached. Finally, the oxygen vacancy-defect type manganese-based monolithic catalyst is obtained by calcination in a high-purity nitrogen atmosphere with appropriate oxygen content.

[0016] Further, in step (1), the concentration of the mixed acid is 1-10 mol / L, the solid-liquid ratio of the mixed acid is 10-100 g / L, the constant temperature soaking temperature is 30-80°C, the soaking time is 3-8 h, the drying temperature is 100-150°C, and the drying time is 6-12 h.

[0017] Further, in step (1), the calcination method is as follows: first, increase the temperature from room temperature to 200-350°C at a rate of 1-10°C / min in a high-purity nitrogen atmosphere, and then increase the temperature to 400-900°C at a rate of 10-20°C / min in a high-purity nitrogen atmosphere with an oxygen content of 10-50 vol% and a constant temperature of 200-350°C for 90-180 min. Finally, decrease the temperature to room temperature at a rate of 5-15°C / min.

[0018] Further, in step (2), the concentration of the organic acid is 30-500 g / L, the stirring rate of the rotary evaporator is 100-400 rpm, the temperature is 30-95℃, the ultrasonic time is 1-6 h, and the number of recycling Li is 3-6 times; the drying temperature is 115-150℃, and the drying time is 12-24 h; the calcination method of the powder catalyst is as follows: first, increase the temperature from room temperature to 250-400℃ at a rate of 5-25℃ / min in a high-purity nitrogen atmosphere, and then keep the temperature at 250-400℃ for 60-240 min; then, increase the temperature to 450-800℃ at a rate of 5-20℃ / min in a high-purity nitrogen atmosphere with an oxygen content of 5-60 vol%, and keep the temperature at 450-800℃ for 3-9 h; finally, decrease the temperature to room temperature at a rate of 5-20℃ / min.

[0019] Further, in step (3), the mixed acid includes one or more of hydrochloric acid, acetic acid, sulfuric acid, oxalic acid, and citric acid, and the pH of the slurry is maintained at 3-9.

[0020] Further, in step (3), the mass ratio of the silica sol, pseudo-boehmite, and hydroxyl cellulose to cordierite is 0.5-5%, the ultrasonic-assisted impregnation time is 10-60 min, the final loading of the active substance is 10-50%, the drying temperature is 120-200℃, and the number of repeated impregnation is 2-5.

[0021] Further, in step (3), the calcination method is as follows: first, increase the temperature from room temperature to 250-400℃ at a rate of 5-15℃ / min in a high-purity nitrogen atmosphere, and then keep the temperature at 250-400℃ for 60-360 min; then, increase the temperature to 450-850℃ at a rate of 10-30℃ / min in a high-purity nitrogen atmosphere with an oxygen content of 5-50 vol%, and keep the temperature at 450-850℃ for 6-12 h; finally, decrease the temperature to room temperature; in step (3), the ball milling uses zirconia, the mass ratio of isopropyl alcohol to powder is 0.6-1.5, and the mass ratio of zirconia to powder is 3-9.

[0022] An oxygen vacancy-defect type manganese-based monolithic catalyst for catalytic oxidation of VOCs and simultaneous catalytic removal of NOx and VOCs in flue gas, the mixed weak acid and unique mixed formula and pretreatment process used by the catalyst can effectively obtain purer precursor powder in the pole separation stage, reduce the aluminum content of the positive electrode powder, greatly improve the quality of the waste positive electrode powder, and make the lithium leach gently, increase the material surface defects and oxygen vacancies, and keep the basic crystal framework in the material during the lithium extraction and catalyst preparation stage; meanwhile, the low-concentration mixed weak acid has the unique advantages of low cost, low environmental pollution, and easy treatment of waste liquid; after recovering lithium from the waste lithium cobalt oxide material, the catalyst maintains the original crystal structure framework, oxygen vacancies are formed after lithium is removed, the primary particles become nanoparticles, the specific surface area increases, the adsorption capacity is enhanced, high catalytic activity is achieved, and high resistance (resistance to nitrogen oxides, resistance to sulfur, resistance to ammonia and resistance to water) and low-temperature activity are achieved.

[0023] A preparation method of a monolithic catalyst prepared from waste lithium manganese oxide batteries is applied to the fields of solid waste treatment and atmospheric environmental pollution control.

[0024] After the waste lithium manganese oxide battery is disassembled, the positive electrode pole piece is obtained in powder precursor through a novel stripping process, and then the powder precursor is treated by mixed acid and loaded on cordierite by adding a composite binder to prepare a monolithic composite catalyst. The mixed weak acid and additive used in the unique mixed formula can reduce the aluminum content of the positive electrode powder, greatly improve the quality of the waste positive electrode powder, and make the lithium leach gently, increase the material surface defects and oxygen vacancies, and keep the basic crystal framework in the material during the lithium extraction and catalyst preparation stage. Meanwhile, the low-concentration mixed weak acid has the unique advantages of low cost, low environmental pollution, and easy treatment of waste liquid. The prepared catalyst basically maintains the original crystal structure framework, oxygen vacancies are formed after lithium is removed, the primary particles become nanoparticles, the specific surface area increases, the adsorption capacity is enhanced, and high catalytic activity is achieved. The catalyst can not only catalyze the oxidation of volatile organic pollutants, but also simultaneously catalyze the removal of NOx and VOCs in flue gas, and has high catalytic activity, high water resistance, and a wide active temperature range. x Compared with the prior art, the catalyst has the following advantages: x The catalyst can be used for catalytic oxidation of VOCs or simultaneous catalytic removal of NOx and VOC in flue gas at medium and low temperatures of 200-300 DEG C. x Compared with the prior art, the catalyst has the following advantages:

[0025] Compared with the prior art, the catalyst has the following advantages:

[0026] (1) The preparation method adopted in the present application is simple and easy to operate, the active component can be controlled in a large range, and the industrialized scale preparation conditions and practical application value are achieved.

[0027] (2) The oxygen vacancy-defect type manganese-based-powder / monolithic catalyst prepared by the present application basically maintains the original crystal structure and skeleton of the catalyst compared with the prior art, oxygen vacancies are formed after lithium is removed, primary particles become nanoparticles, the specific surface area is increased, the adsorption capacity is enhanced, and the catalyst has high catalytic activity.

[0028] (3) The present application proposes a classification recycling and "waste-to-resource" strategy, which classifies and recovers high-value lithium and transition metals from waste lithium batteries, and prepares catalysts from transition metals. Compared with ordinary catalysts, the catalyst can not only catalyze the oxidation of volatile organic pollutants, but also simultaneously catalyze the removal of NO x and VOCs in flue gas, and exhibits extremely high CO x selectivity in the medium and low temperature range compared with commercial vanadium-based catalysts, and can be widely used in the fields of solid waste resource recovery and degradation of volatile organic pollutants in the atmosphere. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is the XRD pattern of the catalyst of the present application;

[0030] Figure 2 is the SEM pattern of the catalyst of the present application;

[0031] Figure 3 is the oxygen vacancy EPR pattern of the catalyst of the present application;

[0032] Figure 4 is the removal rate of the catalyst of the present application for catalytic oxidation of methylbenzene.

[0033] Figure 5 is the removal rate of the catalyst of the present application for catalytic oxidation of propylene.

[0034] Figure 6 is the long-term stability of the catalyst of the present application for catalytic oxidation.

[0035] Figure 7 is the removal rate of the catalyst of the present application for propylene in the presence of water.

[0036] Figure 8 is the CO2 selectivity of the catalyst of the present application for oxidation of propylene in the presence of water.

[0037] Figure 9 is the simultaneous removal performance of the catalyst of the present application for propylene.

[0038] Figure 10 is the simultaneous removal performance of the catalyst of the present application for NO.

[0039] Figure 11 is the simultaneous removal performance of the catalyst of the present application for propylene in the presence of water and sulfur.

[0040] Figure 12 The catalyst of this invention exhibits water and sulfur resistance while simultaneously removing NO. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.

[0042] Example 1

[0043] Preparation of oxygen vacancy-defect type manganese nanoparticle catalysts.

[0044] First, the waste lithium manganese oxide batteries undergo pretreatment steps including deactivation, disassembly, crushing, and component separation to separate the positive electrode material, copper foil, aluminum foil, carbon powder, and plastic film. The positive electrode sheet is placed in a mixed acid solution of acetic acid and citric acid with a concentration of 5 mol / L and a solid-liquid ratio of 50 g / L. It is then subjected to constant-temperature ultrasonic immersion at 60°C for 6 hours. After drying at 120°C for 10 hours, it is placed in a tube furnace for segmented calcination. The specific calcination method is as follows: first, using high-purity nitrogen as the atmosphere, the temperature is increased from room temperature to 280°C at a rate of 8°C / min, and held at 280°C for 150 minutes. Then, using high-purity nitrogen with an oxygen content of 30 vol%, the temperature is increased to 550°C at a rate of 12°C / min and held at 550°C for 8 hours. Finally, the temperature is reduced to room temperature at a rate of 6°C / min.

[0045] Next, oxalic acid and deionized water were thoroughly mixed, with an oxalic acid concentration of 240 g / L. After sonication, the mixture was placed in a rotary evaporator and stirred at a constant temperature until dissolved. The stirring rate of the rotary evaporator was 280 rpm, the temperature was 65℃, and the sonication time was 1.5 h. The exfoliated lithium manganese oxide precursor prepared in step (1) was added, and after sonication, it was stirred vigorously at a constant temperature. After standing, the upper liquid was poured off, and then deionized water was added for impregnation, and the upper liquid was poured off again. This cycle was repeated 4 times to recover Li, and the Li recovery rate was calculated to be 51%. After Li recovery, the lower slurry was dried, ground, and calcined in stages to obtain a composite powder catalyst. The drying temperature was 125℃, and the drying time was 14 h. The specific calcination method is as follows: First, using high-purity nitrogen as the atmosphere, the temperature is raised from room temperature to 320℃ at a rate of 12℃ / min, and held at 320℃ for 200min. Then, using high-purity nitrogen with an oxygen content of 25 vol%, the temperature is raised to 500℃ at a rate of 15℃ / min and held at 500℃ for 8h. Finally, the temperature is lowered to room temperature at a rate of 6℃ / min. The oxygen vacancy-defect type manganese nanoparticle catalyst is obtained.

[0046] X-ray diffraction pattern of the catalyst ( Figure 1 ) and SEM ( Figure 2It can be seen that the composite catalyst is successfully prepared in this embodiment, and has high crystallinity. The catalyst has similar crystal phase with lithium manganate, indicating that the catalyst basically maintains the original crystal structure and framework. It can be seen from the low-temperature EPR (electron paramagnetic resonance) spectrum of the catalyst that the prepared catalyst has a very high oxygen vacancy concentration. Figure 3

[0047] Example 2

[0048] Preparation of oxygen vacancy-defect type manganese-based monolithic catalyst

[0049] Firstly, the waste lithium manganate battery is pretreated by deactivation, disassembly, crushing and component separation steps to separate the positive electrode material, copper foil, aluminum foil, carbon powder and plastic film. The positive electrode sheet is placed in a mixed acid of acetic acid and citric acid with a concentration of 5 mol / L, the solid-liquid ratio is 50 g / L, the constant temperature ultrasonic immersion temperature is 60℃, the immersion time is 6h, after drying at 120℃ for 10h, it is placed in a tube furnace for step-by-step calcination. The specific calcination method is as follows: first, use high-purity nitrogen as the atmosphere, and increase the temperature from room temperature to 280℃ at a rate of 8℃ / min, and keep the temperature at 280℃ for 150min, then use high-purity nitrogen with an oxygen content of 30vol% as the atmosphere, and increase the temperature to 550℃ at a rate of 12℃ / min, and keep the temperature at 550℃ for 8h, finally, decrease the temperature to room temperature at a rate of 6℃ / min;

[0050] Secondly, oxalic acid and deionized water are mixed thoroughly, and the concentration of oxalic acid is 240g / L. After ultrasonic, it is placed in a rotary evaporator for constant temperature and thorough stirring to dissolve it. The stirring rate of the rotary evaporator is 280rpm, the temperature is 65℃, and the ultrasonic time is 1.5h. The exfoliated lithium manganate precursor prepared in step (1) is added, and after ultrasonic, it is continuously stirred at constant temperature. After standing, the upper liquid is poured out, and then the lower liquid is immersed in deionized water and poured out, and the cycle is repeated 5 times to recover Li. The recovery rate of Li is calculated to be 51%. After recovering Li, the lower slurry liquid is dried, ground, and step-by-step calcined to obtain a composite powder catalyst. The drying temperature is 125℃, and the drying time is 14h. The specific calcination method is as follows: first, use high-purity nitrogen as the atmosphere, and increase the temperature from room temperature to 320℃ at a rate of 12℃ / min, and keep the temperature at 320℃ for 200min, then use high-purity nitrogen with an oxygen content of 25vol% as the atmosphere, and increase the temperature to 500℃ at a rate of 15℃ / min, and keep the temperature at 500℃ for 8h, finally, decrease the temperature to room temperature at a rate of 6℃ / min;

[0051] ​Finally, the coptite is soaked in mixed acid for 3.5 h, washed with distilled water until the washing liquid is neutral, then dried at 130°C for 5 h, transferred to a muffle furnace and calcined at 460°C for 6 h to remove the adsorbed impurities; the obtained composite powder catalyst is ball milled, then mixed with hydrochloric acid and oxalic acid, and placed in a rotary evaporator for constant temperature and sufficient stirring to dissolve the mixture, then hydroxyl cellulose is added, the pH is adjusted, the slurry pH is kept at 5.5, and after stirring, a stable slurry is formed, the coptite block is immersed in the slurry for ultrasonic loading, then the residual suspension is blown to form a uniform film on the surface of the substrate, dried, and the immersion process is repeated, and finally a monolithic catalyst is obtained by stepwise calcination. The mass ratio of hydroxyl cellulose to coptite is 0.6%, the ultrasonic assisted immersion time is 15 min, the final loading amount of active substances is 28%, the drying temperature is 125°C, and the number of repeated immersions is 4. The specific calcination method is as follows: first, the temperature is raised from room temperature to 320°C at a rate of 8°C / min in a high-purity nitrogen atmosphere, kept at 320°C for 240 min, then raised to 500°C at a rate of 12°C / min in a high-purity nitrogen atmosphere with an oxygen content of 25 vol%, kept at 500°C for 10 h, and finally reduced to room temperature.

[0052] Example 3

[0053] Evaluation of catalytic oxidation activity of toluene:

[0054] The degradation reaction of catalytic oxidation of toluene is carried out on a self-made reactor, and the test conditions are as follows: the concentration of toluene is 50 ppm, the catalyst dosage is 200 mg, the reaction temperature is 125°C-390°C, the reaction flow rate is 100 mL / min, the space velocity is 30000 h -1 , 20 vol% O2, N2 as the balance gas; the concentration values of toluene and CO x are detected by a gas chromatograph with a hydrogen ion flame (FID) detector and a connected nickel converter. Figure 4 The evaluation diagram of the removal rate of toluene catalytic oxidation by the catalyst prepared in the application shows that the reaction temperature (T 90 ) of the catalyst prepared in the application for toluene catalytic oxidation removal rate reaching 90% is 225°C, which indicates that the catalyst prepared in the application exhibits excellent catalytic oxidation VOCs low-temperature activity.

[0055] Example 4

[0056] Evaluation of catalytic oxidation activity of propylene:

[0057] The degradation reaction of catalytic oxidation of propylene is carried out on a self-made reactor, and the test conditions are as follows: the concentration of propylene is 100 ppm, the catalyst dosage is 200 mg, the reaction temperature is 125°C-390°C, the reaction flow rate is 100 mL / min, the space velocity is 30000 h -1, 20 vol% O2, N2 as the balance gas; the concentration values of toluene and CO2 were detected by a gas chromatograph with a flame ionization detector (FID) and a nickel converter. Figure 5 The catalyst prepared in the application Figure 5 a) and a commercial MnCu catalyst Figure 5 b) were evaluated for catalytic oxidative degradation of propylene. The results showed that the reaction temperature (T 90 ) at which the removal rate of propylene reached 90% was 213°C for the catalyst prepared in the application, and the reaction temperature (T 90 ) at which the removal rate of propylene reached 90% was 263°C for the best commercial MnCu catalyst, which was increased by more than 40°C, indicating that the catalyst prepared in the application exhibited excellent catalytic oxidation low-temperature activity.

[0058] Example 5

[0059] Stability test of the catalyst

[0060] The catalytic oxidation stability of the catalyst prepared in the application was explored using propylene (C3H6) as a probe molecule. The catalytic oxidation reaction was carried out on a self-made reactor, and the test conditions were as follows: the propylene concentration was 100 ppm, the catalyst dosage was 200 mg, the reaction temperature was 300°C, the reaction flow rate was 100 mL / min, and the space velocity was 30000 h -1 -1. 20 vol% O2, N2 as the balance gas; the concentration values of propylene and CO2 were detected by a gas chromatograph with a flame ionization detector (FID) and a nickel converter. Figure 6 The stability of the catalyst prepared in the application for catalytic oxidative degradation of propylene was evaluated, and the results showed that the removal rate of propylene remained above 99% after 160 hours of long-time reaction, indicating that the catalyst prepared in the application exhibited excellent catalytic oxidation VOCs stability.

[0061] Example 6

[0062] Water resistance test of the catalyst

[0063] The water resistance of the catalyst prepared in the application was explored using propylene (C3H6) as a probe molecule. The test conditions were as follows: the propylene concentration was 100 ppm, the catalyst dosage was 200 mg, the reaction temperature was 300°C, the reaction flow rate was 100 mL / min, and the space velocity was 30000 h -1 -1. The reaction atmosphere was simulated air, 20 vol% O2, and the concentration of H2O was 1 vol%, and N2 was the balance gas; the real-time concentration values of propylene, CO, CO2 and H2O were tested online by a MultiGas2030 infrared Fourier transform spectrometer of the United States MKS company, and the values of each gas component were taken every 5 seconds.Figure 7 The removal rate of the catalyst on the catalytic oxidative degradation of propylene, Figure 8 The CO2 selectivity of the catalyst on the catalytic oxidation of propylene. The results show that after adding 1 vol% of H2O, the removal rate of the catalyst prepared in the application on propylene reaches 99%, and the CO2 selectivity reaches 98%, which shows excellent water resistance.

[0064] Example 7

[0065] Synchronous removal performance test of the catalyst

[0066] Propylene (C3H6) is used as a probe molecule to explore the activity of the catalyst prepared in the application in the synchronous removal of NO and C3H6. The test conditions are: propylene concentration is 100 ppm, catalyst dosage is 200 mg, reaction temperature is 250°C, reaction flow rate is 100 mL / min, space velocity is 30000 h-1, NH3 concentration is 500 ppm, NO concentration is 500 ppm, 10 vol% O2, and N2 is the balance gas; the real-time concentration values of propylene, CO, CO2, NO, N2O, NO2, NH3 and H2O are tested online and synchronously by using the MultiGas2030 infrared Fourier transform spectrum analyzer of the American MKS company. -1 Figure 9 The removal rate of the catalyst prepared in the application on propylene, Figure 10 The removal rate of the catalyst prepared in the application on NO. The experimental results show that the catalyst prepared in the application can synchronously remove VOCs and NO, the removal rate of the catalyst on propylene reaches 99%, and the removal rate of the catalyst on NO respectively reaches 93%.

[0067] Example 8

[0068] Water and sulfur resistance and synchronous removal activity of the catalyst at low temperature

[0069] Propylene (C3H6) is used as a probe molecule to explore the activity and water and sulfur resistance of the catalyst prepared in the application in the synchronous removal of NO and C3H6 at low temperature. The test conditions are: propylene concentration is 100 ppm, catalyst dosage is 200 mg, reaction temperature is 250°C, reaction flow rate is 100 mL / min, space velocity is 30000 h-1, NH3 concentration is 500 ppm, NO concentration is 500 ppm, 10 vol% O2, H2O concentration is 1 vol%, SO2 concentration is 100 ppm, and N2 is the balance gas; the real-time concentration values of propylene, CO, CO2, NO, NH3 and H2O are tested online and synchronously by using the MultiGas2030 infrared Fourier transform spectrum analyzer of the American MKS company. -1 Figure 11 The removal rate of the catalyst prepared in the application on propylene, Figure 12 ​​The removal rate of the catalyst prepared in the application to NO. The experimental results show that the catalyst prepared in the application can simultaneously remove propylene and NO in the complex flue gas in which sulfur, water, NO and C3H6 exist simultaneously, the removal rate of the catalyst to propylene reaches 90%, and the removal rate of the catalyst to NO reaches 84% respectively. At the same time, it shows that the catalyst prepared in the application has excellent resistance to nitrogen oxides, sulfur, ammonia and water, has a wide active temperature range and high catalytic selectivity.

[0070] The above examples are only used to illustrate the technical solutions of the present application and not strictly limited conditions, and those skilled in the art should understand that various changes can be made to the details or forms without departing from the spirit and scope of the present application defined in the claims.

Claims

1. A method for preparing an integral catalyst using spent lithium manganese oxide batteries, characterized in that, After dismantling spent lithium manganese oxide batteries, the positive electrode sheet is pretreated and subjected to a segmented stripping process to obtain acid-etched defect-type manganese nanoparticles. Then, oxygen-vacancy-defect-type manganese nanoparticles are obtained through selective lithium recovery and mixed acid etching. Finally, a composite binder is added and the nanoparticles are loaded onto a cordierite carrier to prepare a product suitable for medium- and low-temperature catalytic oxidation of VOCs and simultaneous catalytic removal of NO from flue gas. x The mixed acid is a weak acid and is a manganese-based powder / monolithic catalyst with oxygen vacancy-deficient VOCs.

2. The method for preparing an integral catalyst using spent lithium manganese oxide batteries according to claim 1, characterized in that, The method includes all or part of the following steps: (1) Preparation of weak acid etching-defect type manganese nanoparticle precursor: The waste lithium manganese oxide batteries undergo pretreatment steps including deactivation, disassembly, crushing, and component separation to separate the positive electrode material, copper foil, aluminum foil, carbon powder, and plastic film. The positive electrode sheet is placed in a mixed acid, ultrasonically immersed at a constant temperature, dried, and then calcined in a tube furnace in stages. After grinding and sieving, defective manganese nanoparticles are obtained for later use. The mixed acid includes one or more of acetic acid, oxalic acid, and citric acid. The atmosphere of the tube furnace is nitrogen, argon, high-purity nitrogen, or nitrogen with an oxygen content of 5-90 vol%. (2) Selective recovery of lithium and preparation of oxygen vacancy-defect type manganese nanoparticles: The organic acid was thoroughly mixed with deionized water and placed in a rotary evaporator for constant temperature and stirring until dissolved. The oxygen vacancy-defect type manganese nanoparticles prepared in step (1) were added. After sonication, the mixture was stirred vigorously at a constant temperature. After standing, the upper liquid was poured off. Then, deionized water was added for impregnation, and the upper liquid was poured off again. Li was recovered through multiple cycles. After Li recovery, the lower slurry was dried, ground, and calcined in stages to obtain the oxygen vacancy-defect type manganese nanoparticle / powder catalyst. The organic acid included one or more of acetic acid, oxalic acid, and citric acid. (3) Preparation of oxygen vacancy-defect type manganese-based monolithic catalyst: Cordierite was soaked in a mixed acid for 2–6 h, then washed with distilled water until the pH of the washing solution was neutral. It was then dried at 110–180 °C for 4–8 h and transferred to a muffle furnace for calcination at 350–750 °C for 3–8 h to remove various adsorbed impurities. The composite powder catalyst prepared in step (2) was ball-milled, mixed acid was added, and it was placed in a rotary evaporator and stirred at a constant temperature to dissolve it. One or two of silica sol, pseudoboehmite, and hydroxycellulose were added, the pH was adjusted, and a stable slurry was formed after stirring. Cordierite blocks were ultrasonically impregnated and loaded in the above slurry, and then the residual suspension was blown off to form a uniform film on the substrate surface. The film was dried, and the impregnation process was repeated until the appropriate loading was obtained. Finally, it was calcined in high-purity nitrogen with appropriate oxygen content in stages to obtain an oxygen vacancy-defect type manganese-based monolithic catalyst.

3. The method for preparing an integral catalyst using spent lithium manganese oxide batteries according to claim 2, characterized in that, In step (1), the concentration of the mixed acid is 1-10 mol / L, the solid-liquid ratio of the mixed acid is 10-100 g / L, the constant temperature soaking temperature is 30-80℃, the soaking time is 3-8 h, the drying temperature is 100-150℃, and the drying time is 6-12 h.

4. The method for preparing an integral catalyst using waste lithium manganese oxide batteries according to claim 2, characterized in that, In step (1), the specific method of calcination is as follows: first, using high-purity nitrogen as the atmosphere, the temperature is raised from room temperature to 200-350℃ at a rate of 1-10℃ / min, and kept at 200-350℃ for 90-180min. Then, using high-purity nitrogen with an oxygen content of 10-50 vol%, the temperature is raised to 400-900℃ at a rate of 10-20℃ / min, and kept at 200-350℃ for 6-12h. Finally, the temperature is lowered to room temperature at a rate of 5-15℃ / min.

5. The method for preparing an integral catalyst using spent lithium manganese oxide batteries according to claim 2, characterized in that, In step (2), the concentration of the organic acid is 30-500 g / L, the stirring speed of the rotary evaporator is 100-400 rpm, the temperature is 30-95℃, the ultrasonic time is 1-6 h, and the number of times Li is recycled is 3-6 times; the drying temperature is 115-150℃, and the drying time is 12-24 h; the specific method of calcination of the powder catalyst is as follows: first, using high-purity nitrogen as an atmosphere, the temperature is raised from room temperature to 250-400℃ at a rate of 5-25℃ / min, and kept at 250-400℃ for 60-240 min; then, using high-purity nitrogen with an oxygen content of 5-60 vol%, the temperature is raised to 450-800℃ at a rate of 5-20℃ / min, and kept at 3-9 h; finally, the temperature is lowered to room temperature at a rate of 5-20℃ / min.

6. The method for preparing an integral catalyst using spent lithium manganese oxide batteries according to claim 2, characterized in that, In step (3), the mixed acid includes one or more of hydrochloric acid, acetic acid, sulfuric acid, oxalic acid and citric acid, and the pH of the slurry is maintained at 3 to 9.

7. The method for preparing an integral catalyst using spent lithium manganese oxide batteries according to claim 2, characterized in that, In step (3), the mass ratio of silica sol, pseudoboehmite, hydroxycellulose and cordierite is 0.5-5%, the ultrasonic-assisted impregnation time is 10-60 min, the final loading of active material is 10-50%, the drying temperature is 120-200℃, and the number of repeated impregnations is 2-5 times.

8. The method for preparing an integral catalyst using waste lithium manganese oxide batteries according to claim 2, characterized in that, In step (3), the specific method of calcination is as follows: first, using high-purity nitrogen as the atmosphere, the temperature is raised from room temperature to 250-400℃ at a rate of 5-15℃ / min, and held at 250-400℃ for 60-360 min. Then, using high-purity nitrogen with an oxygen content of 5-50 vol%, the temperature is raised to 450-850℃ at a rate of 10-30℃ / min, and held at 250-400℃ for 6-12 h. Finally, the temperature is lowered to room temperature. In step (3), the ball milling uses zirconium oxide, the mass ratio of isopropanol to powder is 0.6-1.5, and the mass ratio of zirconium oxide to powder is 3-9.

9. A reagent for catalytic oxidation of VOCs and simultaneous catalytic removal of NO from flue gas, prepared by the method according to any one of claims 1 to 8. x The catalyst is a manganese-based monolithic catalyst with oxygen vacancy-defects in VOCs. The catalyst recovers lithium from battery materials, maintains the original crystal structure framework, and forms oxygen vacancies after lithium is extracted. The primary particles are transformed into nanoparticles, increasing the specific surface area and enhancing the adsorption capacity. It has high catalytic activity, exhibits high resistance and low-temperature activity. The resistance includes resistance to nitrogen oxides, sulfur, ammonia and water.

10. The catalyst of claim 9 is used for the catalytic oxidation of VOCs and the simultaneous catalytic removal of NO from flue gas. x The oxygen vacancy-defect type manganese-based monolithic catalyst for VOCs and lithium recovery process are applied to the fields of solid waste treatment and resource utilization and air pollution control.

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