Method for synthesizing lead-free piezoelectric catalytic material based on hydrothermal technology and product

Abstract

The invention discloses a method for synthesizing a lead-free piezoelectric catalytic material based on a hydrothermal technology and a product, and belongs to the field of catalytic materials and pollution abatement, the synthesis method of the lead-free piezoelectric catalytic material comprises the following steps: mixing and stirring an ammonium carbonate solution and a soluble zinc salt solution, carrying out hydrothermal reaction to obtain a reaction product solid, and drying the reaction product solid to obtain the lead-free piezoelectric catalytic material. Calcining the reaction product solid in an air atmosphere at 400-500 DEG C to obtain a calcined product; further putting the calcined product into water for ultrasonic treatment, then adding soluble bismuth salt, stirring and mixing, putting into a hydrothermal reaction kettle for hydrothermal reaction at 160-180 DEG C, and obtaining the lead-free piezoelectric catalytic material after the reaction is finished. The component of the lead-free piezoelectric catalytic material is ZnO (at) Bi2O2 (OH) NO3, and the lead-free piezoelectric catalytic material is a two-dimensional sheet-shaped stacked nano material and shows a rapid and efficient piezoelectric catalytic characteristic.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic materials and pollution control technology, in particular to a method for synthesizing lead-free piezoelectric catalytic materials based on hydrothermal technology and products. BACKGROUND

[0002] Piezoelectric catalytic technology has shown great potential in environmental remediation (such as degradation of organic pollutants), clean energy (such as water splitting for hydrogen production), and biomedical fields. However, current high-performance piezoelectric material systems are heavily dependent on lead-containing (such as lead zirconate titanate PZT) materials, which are heavy metals with strong neurotoxicity. There is a risk of lead leakage and diffusion in the whole life cycle of material preparation, use and disposal, which poses a long-term threat to the ecosystem and public health. Therefore, it is urgent to develop high-performance lead-free piezoelectric catalytic materials to meet the requirements of green chemistry and broaden the application fields of piezoelectric catalytic technology.

[0003] Organic pollutants, especially toxic and refractory organic matter, have persistence, bioaccumulation and toxicity in water environment. If they are not effectively degraded or mineralized by physical, chemical or biological methods, they will pose a long-term threat to the aquatic ecosystem and may be enriched through the food chain, ultimately endangering human health. Odorants in water bodies are mainly organic pollutants, and typical odorants include geosmin and 2-methylisoborneol (2-MIB), etc. Such substances show strong resistance to conventional water treatment processes, therefore, developing efficient degradation technology is the key to addressing the dual challenges of water environmental safety and sensory quality of drinking water.

[0004] The Chinese patent document with publication number CN120286009A discloses a high-performance lead-free piezoelectric catalytic material and its preparation method and application. The preparation method of the lead-free piezoelectric catalytic material includes the following steps: weighing K2CO3, Na2CO3, Nb2O5, Fe2O3, Co2O3, mixing and then performing ultrasonic dispersion treatment, followed by powder grinding and pre-sintering treatment to obtain a precursor powder; the precursor powder is ground again, followed by tabletting to obtain a green body; the green body is subjected to sintering treatment and crushing treatment in sequence to obtain a ceramic powder; the ceramic powder is subjected to ultrasonic treatment in pure water, followed by drying treatment to obtain a lead-free piezoelectric catalytic material. The lead-free piezoelectric catalytic material has a very obvious effect on piezoelectric catalytic degradation of rhodamine B, but the preparation condition temperature requirement is relatively harsh and the energy consumption is high.

[0005] The Chinese patent document with the publication number CN120815525A discloses a preparation method and application of a composite piezoelectric catalytic material NaNbO3@BiFeO3 for rapidly degrading antibiotics. NaNbO3 is a flaky grain with

[001] crystallographic orientation prepared by a two-step molten salt method, and BiFeO3 is a micro-nano particle prepared by a coprecipitation method. After the composite micro-nano BiFeO3 powder and the

[001] -oriented NaNbO3 flaky grain form a heterojunction, the composite piezoelectric catalytic material exhibits rapid and efficient piezoelectric photocatalytic properties. However, the application also has problems of high temperature requirement and high energy consumption.

[0006] Therefore, it is urgent to develop a new piezoelectric catalytic material with high efficient adsorption-catalysis dual functions, low cost and low energy consumption, so as to realize deep catalytic degradation of odor pollutants. SUMMARY

[0007] The application provides a method for synthesizing a lead-free piezoelectric catalytic material based on a hydrothermal technology, which has simple and efficient process, mild conditions and low energy consumption, and the prepared lead-free piezoelectric catalytic material can realize deep catalytic degradation of organic pollutants.

[0008] The specific technical solutions are as follows: A method for synthesizing a lead-free piezoelectric catalytic material based on a hydrothermal technology, comprising the following steps: (1) mixing and stirring ammonium carbonate solution and soluble zinc salt solution, and then placing the mixture in a hydrothermal reactor for hydrothermal reaction at 170-190 DEG C. After the reaction, the reaction product solid is obtained by cleaning and drying. The reaction product solid is calcined at 400-500 DEG C in an air atmosphere to obtain a calcined product; (2) placing the calcined product obtained in step (1) in water for ultrasonic treatment, and then adding soluble bismuth salt to the ultrasonic treatment system. After stirring and mixing, the mixture is placed in a hydrothermal reactor for hydrothermal reaction at 140-180 DEG C. After the reaction, the lead-free piezoelectric catalytic material is obtained by cleaning and drying.

[0009] The application synthesizes ZnO-Bi2O2 (OH) NO3 heterojunction as a lead-free piezoelectric catalytic material through two-step hydrothermal reaction. The electrons are gathered on the ZnO side, and the holes are gathered on the Bi2O2 (OH) NO3 side, realizing complete separation in space and greatly reducing the probability of electron-hole recombination, so as to provide more available carriers for the catalytic reaction.

[0010] Preferably, the soluble zinc salt is zinc nitrate hexahydrate, and the soluble bismuth salt is bismuth nitrate pentahydrate.

[0011] Preferably, in step (1), the concentration of the ammonium carbonate solution is 1.2-1.8 mol / L, the concentration of the soluble zinc salt solution is 1.2-1.8 mol / L, and the ammonium carbonate solution is slightly excessive to the zinc nitrate after mixing.

[0012] Preferably, in step (1), the hydrothermal reaction condition is 175-180℃, 22-25 h.

[0013] Preferably, in step (1), the reaction product solid is calcined at 400-450℃ in an air atmosphere for 1-2 h.

[0014] Further, the parameter of the ultrasonic treatment is 20-40 kHz, 0.5-2 h. The ultrasonic process is used to disperse the calcined product, so that it is uniformly distributed in water and uniformly mixed with the soluble bismuth salt.

[0015] Preferably, in step (2), the amount of the soluble bismuth salt added is equal to the mass of the calcined product in the ultrasonic treatment system, so that the concentration of bismuth ions is about 20% of the molar concentration of zinc oxide.

[0016] Preferably, in step (2), the hydrothermal reaction is carried out after the solution appears milky white after stirring and mixing.

[0017] The application also provides a lead-free piezoelectric catalytic material synthesized by the method for synthesizing a lead-free piezoelectric catalytic material based on a hydrothermal technology.

[0018] The lead-free piezoelectric catalytic material is a two-dimensional layered stacked nanosheet structure with a ZnO-Bi2O2(OH)NO3 heterojunction, can be reused after regeneration treatment, and can be regenerated after being filtered and dried. It has excellent technical effects in the adsorption-catalysis of organic pollutants such as odor pollutants.

[0019] Compared with the prior art, the application has the following advantages: (1) The lead-free piezoelectric catalytic material prepared by the method can be reused through simple regeneration treatment, significantly reducing the cost, and the long-term usability of the material is good. The preparation process of the lead-free piezoelectric catalytic material is simple and efficient, the conditions are mild, and the energy consumption is low.

[0020] (2) The lead-free piezoelectric catalytic material prepared by the method can be processed into various forms such as sheet, fiber or powder to adapt to different application scenarios. The diversity and variability of the material provide high adaptability and operational flexibility for extensive industrial applications.

[0021] (3) The lead-free piezoelectric catalytic material ZnO@Bi2O2(OH)NO3 prepared by the method has fast and efficient piezoelectric catalytic characteristics, in the ZnO@Bi2O2(OH)NO3, the electrons are gathered on the side of ZnO, the holes are gathered on the side of Bi2O2(OH)NO3, the complete separation in space is realized, the probability of electron-hole recombination is greatly reduced, more available carriers are provided for the catalytic reaction, and the lead-free piezoelectric catalytic material has good application prospect in trace removal of organic pollutants, especially odor pollutants. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The SEM diagram of the lead-free piezoelectric catalytic material prepared for example 1.

[0023] Figure 2 The XRD diagram of the calcined product and the lead-free piezoelectric catalytic material in example 1.

[0024] Figure 3 The degradation effect diagram of the lead-free piezoelectric catalytic material prepared for example 1 on dimethyl isochroman and geosmin after adsorption three times and ultrasonic degradation ten times.

[0025] Figure 4 The degradation effect diagram of the lead-free piezoelectric catalytic material prepared for example 1 on rhodamine B. DETAILED DESCRIPTION

[0026] In order to make the objects, features and advantages of the present application more apparent and easy to understand, the following will be described in detail through specific embodiments. In the following description, a lot of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, so the present application is not limited by the specific embodiments disclosed below. The technical features in each embodiment of the present application can be combined accordingly without mutual conflict.

[0027] The operation methods not specified in the following examples are usually carried out according to the conventional conditions, or according to the conditions recommended by the manufacturers. The contents not described in detail in the specification belong to the prior art known to those skilled in the art. The experimental materials used in the following examples can be purchased from conventional biochemical reagent companies, unless otherwise specified.

[0028] Example 1 Take 150 mL ultrapure water to add 66.9 g zinc nitrate hexahydrate, magnetic stirring 420 rpm, 10 min, to obtain a soluble zinc salt solution; take 750 mL ultrapure water to add 108 g ammonium carbonate, magnetic stirring 600 rpm, 10 min, to obtain an ammonium carbonate solution; about 150 mL of ammonium carbonate solution is added to the zinc nitrate solution, so that the ammonium carbonate is slightly excessive to the zinc nitrate, magnetic stirring 420 rpm, 30 min, and then the resulting mixed solution is added to a 500 mL hydrothermal reactor, hydrothermal reaction at 180℃ for 24 h, cooled to 25℃, and then taken out and washed with water, washed twice with 200 mL of ultrapure water, and washed twice with 100 mL of anhydrous ethanol. After washing, vacuum drying at 60℃ for 12 h, and then calcined at 400℃ in a muffle furnace under air atmosphere for 1 h to obtain a calcined product of two-dimensional sheet-shaped zinc oxide powder.

[0029] Take 45 g of the calcined product and add it to 300 mL of ultrapure water, and ultrasonically treat it at 25 kHz for 1 h. Add bismuth nitrate pentahydrate with the same mass as the calcined product to the ultrasonically treated bottle, and mix uniformly under magnetic stirring at 420 rpm for 30 min until the solution appears as a milky white liquid. Add the mixed solution to a 500 mL hydrothermal reactor, and hydrothermal at 180℃ for 12 h. Cool to 25℃, take out and wash with water, wash twice with 200 mL of ultrapure water, and wash twice with 100 mL of anhydrous ethanol. After washing, vacuum drying at 60℃ for 12 h, and then the lead-free piezoelectric catalytic material is obtained. The SEM image of the lead-free piezoelectric catalytic material is shown in Figure 1 As shown in

[0030] As shown in Figure 2 The XRD pattern of the calcined product ZnO is highly matched with the standard reference card PDF #97-015-4487, and the diffraction peaks at 2θ values of 31.75°, 34.42°, 36.21°, 47.60°, 56.64° and 62.83° can be attributed to the (100), (002), (101), (102), (110) and (103) crystal planes of ZnO. With the introduction of Bi2O2(OH)NO3, additional diffraction peaks at 10.31° and 31.37° correspond to the (002), (114) characteristic peaks of Bi2O2(OH)NO3, indicating the successful synthesis of ZnO-Bi2O2(OH)NO3 binary nanocomposite.

[0031] Figure 3 and Figure 4The results show that the lead-free piezoelectric catalytic material can achieve 100% deep removal of trace odor pollutants (geosmin and 2-methylisoborneol) in drinking water sources within 15 minutes, and has excellent piezoelectric catalytic performance. For dye organic pollutants represented by rhodamine B, more than 80% removal efficiency can be achieved within 30 minutes, and more than 95% removal efficiency can be achieved within 40 minutes. The effect is better after polarization by a polarization instrument (6-8 kV polarization for 1 h at room temperature).

[0032] Example 2 The calcined product prepared in Example 1 was added to 300 mL of ultrapure water, and ultrasonic treatment was performed at 25 kHz for 1 h. Bismuth nitrate pentahydrate with the same mass as the calcined product was added to the bottle after ultrasonic treatment, and magnetic stirring was performed at 420 rpm for 30 min until the solution appeared as a milky white liquid. The mixed solution was added to a 500 mL hydrothermal reaction kettle, and hydrothermal treatment was performed at 160℃ for 12 h. After cooling to 25℃, the product was taken out and washed with water. The product was washed twice with 200 mL of ultrapure water and twice with 100 mL of anhydrous ethanol. After washing, the product was dried in a vacuum drying oven at 60℃ for 12 h. The lead-free piezoelectric catalytic material was obtained after drying.

[0033] Example 3 150 mL of ultrapure water was added to 66.9 g of zinc nitrate hexahydrate, and magnetic stirring was performed at 420 rpm for 30 min to obtain a soluble zinc salt solution. 150 mL of ultrapure water was added to 21.6 g of ammonium carbonate, and magnetic stirring was performed at 420 rpm for 20 min to obtain an ammonium carbonate solution. About 150 mL of the ammonium carbonate solution was added to the zinc nitrate solution, and the ammonium carbonate was slightly excessive to the zinc nitrate. Magnetic stirring was performed at 420 rpm for 30 min, and then the mixed solution was added to a 500 mL hydrothermal reaction kettle. Hydrothermal reaction was performed at 180℃ for 25 h. After cooling to 25℃, the product was taken out and washed with water. The product was washed twice with 200 mL of ultrapure water and twice with 100 mL of anhydrous ethanol. After washing, the product was dried in a vacuum drying oven at 60℃ for 12 h. The calcined product, two-dimensional sheet-shaped zinc oxide powder, was obtained after calcination in a muffle furnace at 400℃ in an air atmosphere for 1 h.

[0034] The calcined product was added to 300 mL of ultrapure water, and ultrasonic treatment was performed at 25 kHz for 1 h. Bismuth nitrate pentahydrate with the same mass as the calcined product was added to the bottle after ultrasonic treatment, and magnetic stirring was performed at 420 rpm for 30 min until the solution appeared as a milky white liquid. The mixed solution was added to a 500 mL hydrothermal reaction kettle, and hydrothermal treatment was performed at 180℃ for 10 h. After cooling to 25℃, the product was taken out and washed with water. The product was washed twice with 200 mL of ultrapure water and twice with 100 mL of anhydrous ethanol. After washing, the product was dried in a vacuum drying oven at 60℃ for 12 h. The lead-free piezoelectric catalytic material was obtained without calcination.

[0035] Comparative Example 1 The calcined product prepared in Example 1 was added to 300 mL of ultrapure water, and ultrasonic treatment was performed at 25 kHz for 1 h. Bismuth nitrate pentahydrate with the same mass as the calcined product was added to the bottle after ultrasonic treatment, and magnetic stirring was performed at 420 rpm for 30 min to mix the solution uniformly until the solution appeared as a milky white liquid. The mixed solution was added to a 500 mL hydrothermal reactor, and hydrothermal treatment was performed at 140°C for 5 h. After cooling to 25°C, the product was taken out and washed with water. The product was washed twice with 200 mL of ultrapure water and twice with 100 mL of anhydrous ethanol. After washing, the product was dried in a vacuum drying oven at 60°C for 12 h. After drying, the catalytic material was obtained.

[0036] The experimental results show that, after reducing the hydrothermal time and the hydrothermal temperature, especially reducing the hydrothermal time, the obtained catalytic material does not have the lattice peak of Bi2O2(OH)NO3, and the removal effect of rhodamine B is poor.

[0037] The above examples have described the technical solutions of the present application in detail. It should be understood that the above examples are only specific embodiments of the present application and are not intended to limit the present application. Any modification, supplement or similar replacement within the principle range of the present application should be included in the protection scope of the present application.

Claims

1. A method for synthesizing a lead-free piezoelectric catalytic material based on hydrothermal technology, characterized in that, The method comprises the following steps: (1) mixing and stirring an ammonium carbonate solution and a soluble zinc salt solution, and then placing the mixture in a hydrothermal reaction kettle to perform a hydrothermal reaction at 170-190 DEG C, cleaning and drying the reaction product after the reaction, and obtaining a solid reaction product; calcining the solid reaction product in an air atmosphere at 400-500 DEG C to obtain a calcined product; (2) placing the calcined product obtained in step (1) in water to perform ultrasonic treatment, adding a soluble bismuth salt to the ultrasonic treatment system, mixing and stirring, and then placing the mixture in a hydrothermal reaction kettle to perform a hydrothermal reaction at 140-180 DEG C, cleaning and drying the reaction product after the reaction, and obtaining the lead-free piezoelectric catalytic material.

2. The method for synthesizing lead-free piezoelectric catalytic material based on hydrothermal technology according to claim 1, characterized in that, The soluble zinc salt is zinc nitrate hexahydrate, and the soluble bismuth salt is bismuth nitrate pentahydrate.

3. The method for synthesizing lead-free piezoelectric catalytic material based on hydrothermal technology according to claim 2, characterized in that, In step (1), the concentration of the ammonium carbonate solution is 1.2-1.8 mol / L, and the concentration of the soluble zinc salt solution is 1.2-1.8 mol / L; after mixing the ammonium carbonate solution and the soluble zinc salt solution, the ammonium carbonate is in excess of the zinc nitrate.

4. The method for synthesizing lead-free piezoelectric catalytic material based on hydrothermal technology according to claim 1, characterized in that, In step (1), the hydrothermal reaction conditions are 175-180 DEG C and 22-25 h.

5. The method for synthesizing lead-free piezoelectric catalytic material based on hydrothermal technology according to claim 1, characterized in that, In step (1), the solid reaction product is calcined in an air atmosphere at 400-450 DEG C for 1-2 h.

6. The method for synthesizing lead-free piezoelectric catalytic material based on hydrothermal technology according to claim 1, characterized in that, The ultrasonic treatment parameters are 20-40 kHz and 0.5-2 h.

7. The method for synthesizing lead-free piezoelectric catalytic material based on hydrothermal technology according to claim 1, characterized in that, In step (2), the amount of the soluble bismuth salt added is equal to the mass of the calcined product in the ultrasonic treatment system.

8. The method for synthesizing lead-free piezoelectric catalytic material based on hydrothermal technology according to claim 1, characterized in that, In step (2), the hydrothermal reaction conditions are 170-180 DEG C and 10-12 h.

9. A lead-free piezoelectric catalytic material, characterized by, The lead-free piezoelectric catalytic material is synthesized by the method according to any one of claims 1-8.

Images