Preparation method of long afterglow-bismuth based nano composite photocatalyst and application of photocatalyst in degrading agricultural and veterinary medicines
阅读说明：本技术 一种基于长余辉-铋基纳米复合光催化剂的制备方法及其光催化降解农兽药的应用 (Preparation method of long afterglow-bismuth based nano composite photocatalyst and application of photocatalyst in degrading agricultural and veterinary medicines ) 是由 赵媛 景小慧 于 2021-10-25 设计创作，主要内容包括：本发明提供了一种基于长余辉-铋基纳米复合光催化剂的制备方法及其光催化降解农兽药的应用,属于催化降解领域。所述新型催化剂制备方法包括如下步骤：通过溶剂热法合成了锶掺杂的长余辉纳米棒ZnGeO:SrNRs和BiOI。将两者按比例混合,再通过高温煅烧将BiOI煅烧成带有碘空穴Bi-(5)O-(7)I的新型催化剂。同时,ZnGeO:SrNRs和Bi-(5)O-(7)I两者之间形成了紧密的接触,可以使载流子快速迁移至表面的反应活性位点,以达到较高的载流子分离效率,从而提高光催化反应活性。据此,开发出一种可以用于降解水体农兽药的方法。(The invention provides a preparation method based on a long afterglow-bismuth based nano composite photocatalyst and application of the photocatalyst in photocatalytic degradation of veterinary drugs, belonging to the field of catalytic degradation. The preparation method of the novel catalyst comprises the following steps: the strontium-doped long afterglow nanorods ZnGeO, SrNRs and BiOI are synthesized by a solvothermal method. Mixing the two materials in proportion, calcining the BiOI into Bi with iodine holes by high-temperature calcination 5 O 7 Novel catalysts of formula I. In the meantime, ZnGeO is SrNRs and Bi 5 O 7 I form a compact between the twoThe contact of (2) can enable the carriers to be rapidly transferred to the reactive sites on the surface, so as to achieve higher carrier separation efficiency and improve the photocatalytic reaction activity. Therefore, a method for degrading aquatic pesticide and veterinary drug is developed.)
1. The long afterglow-bismuth based nano composite photocatalyst is characterized in that the nano composite photocatalyst is ZnGeO SrNRs/Bi5O7I; wherein the weight of ZnGeO to SrNRs is ZnGeO to Sr NRs/Bi5O710-60% of the weight of I.
2. The preparation method of the long afterglow-bismuth based nano composite photocatalyst as claimed in claim 1, which is characterized by comprising the following steps:
(1) zn (NO) is added3)2、Sr(NO3)2Mixing with concentrated nitric acid to form colorless transparent solution, adding water and Na2GeO3Adjusting the pH value of the solution to 7-11, uniformly mixing the obtained solution, and carrying out hydrothermal reaction to obtain precipitates, namely the long-afterglow nanorods ZnGeO and SrNRs;
(2) and (2) uniformly mixing the long afterglow nanorod ZnGeO: SrNRs and the BiOI in the step (1), grinding and homogenizing, and calcining the obtained mixture to obtain the nano composite photocatalyst.
3. The method according to claim 2, wherein in the step (1), Zn (NO) is added3)2、Sr(NO3)2The molar ratio is 2:0.01-2: 0.05.
4. The preparation method according to claim 2, wherein in the step (1), the hydrothermal reaction temperature is 120-220 ℃.
5. The method according to claim 2, wherein the hydrothermal reaction is carried out for 2 to 12 hours in the step (1).
6. The preparation method according to claim 2, wherein in the step (2), the mass ratio of the long afterglow nanorods ZnGeO: SrNRs to BiOI is 1:9-6: 4.
7. The production method according to claim 2, wherein in the step (2), the temperature increase rate of the calcination is 2 to 5 ℃/min.
8. The preparation method according to claim 2, wherein in the step (2), the calcination is performed under the calcination condition of 450-600 ℃ for 0.5-8 h.
9. The application of the long afterglow-bismuth based nano composite photocatalyst as claimed in claim 1 in photocatalytic degradation of agricultural and veterinary medicines.
10. The use according to claim 9, wherein said veterinary drug is selected from tetracycline, chloramphenicol, malachite green or acid orange.
Technical Field
The invention belongs to the technical field of catalysis, and particularly relates to a preparation method of a long afterglow-bismuth based nano composite photocatalyst and application of the long afterglow-bismuth based nano composite photocatalyst in photocatalytic degradation of agricultural and veterinary medicines.
Background
The rapid development of modern industry has promoted the development of global economy, and has brought huge energy consumption and environmental pollution. The problems of environment and energy are solved, the sustainable development of economy is realized, and the focus of the attention of scientific research personnel is achieved. The contaminated water contains not only inorganic heavy metal ions but also organic contaminants. The pesticide and veterinary drug residue has a large proportion, and poses a great threat to the health of people. Most of the agricultural and veterinary medicines have stable structures and are difficult to degrade under natural conditions. The long afterglow has the potential in energy conversion and fluorescence, so that the long afterglow becomes a research hotspot. However, due to their wide band gap, many are only active under UV irradiation, and the limited light absorption and rapid recombination of the light-generating carrier prevent the application of long persistence in the field of photocatalysis. Most Bi-based materials have excellent light absorption capacity, wherein the BiOI (bismuth oxyhalide) based material has excellent light absorption performance, but the practical application of the pure-phase photocatalyst caused by rapid recombination of photogenerated carriers is still limited to a certain extent. The modified composite photocatalyst usually shows higher activity after being modified by methods such as cocatalyst loading, semiconductor compounding, ion doping and the like.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a preparation method based on a long afterglow-bismuth based nano composite photocatalyst and application of the photocatalyst in degrading of agricultural and veterinary medicines. The novel catalyst ZnGeO: Sr NRs/Bi with high specific surface and carrier separation efficiency is prepared by compounding the long afterglow nanorod ZnGeO: Sr NRs with blue emission and the BiOI5O7I. The long afterglow nanorod ZnGeO Sr NRs has proper positions of conduction band and valence band, and Bi5O7The I has excellent light response performance and iodine vacancy, and the two are closely contacted and compounded to form a heterojunction, so that the composition of a photon-generated carrier can be inhibited, and pollutants can be efficiently degraded.
Based on long afterglow-bismuth based nano composite photocatalyst, the nano composite photocatalyst is ZnGeO SrNRs/Bi5O7I; wherein the weight of ZnGeO SrNRs is ZnGeO SrNRs/Bi5O710-60% of the weight of I.
The invention also provides a preparation method of the long afterglow-bismuth based nano composite photocatalyst, which is characterized by comprising the following steps:
(1) zn (NO) is added3)2、Sr(NO3)2Mixing with concentrated nitric acid to form colorless transparent solution, adding water and Na2GeO3Adjusting the pH value of the solution to 7-11, uniformly mixing the obtained solution, and carrying out hydrothermal reaction to obtain precipitates, namely the long-afterglow nanorods ZnGeO and SrNRs;
(2) and (2) uniformly mixing the long afterglow nanorod ZnGeO: SrNRs and the BiOI in the step (1), grinding and homogenizing, and calcining the obtained mixture to obtain the nano composite photocatalyst.
In one embodiment of the present invention, in step (1), the Zn (NO)3)2、Sr(NO3)2The molar ratio is 2:0.01-2: 0.05.
In one embodiment of the present invention, in the step (1), the Na2GeO3The concentration of the solution was 0.66 mM/mL.
In one embodiment of the present invention, in step (1), the hydrothermal reaction conditions are: reaction at 120-220 deg.c for 2-12 hr.
In one embodiment of the invention, the mass ratio of the long afterglow nanorod ZnGeO to Sr NRs to the BiOI is 1:9-6: 4.
In one embodiment of the present invention, in the step (2), the temperature increase rate of the calcination is 2 to 5 ℃/min.
In one embodiment of the present invention, in the step (2), the calcination is performed under the calcination condition of 450 ℃ to 600 ℃ for 0.5 to 8 hours. The molar ratio of Zn to Ge in the long afterglow nanorod ZnGeO: SrNRs is 2: when the calcination temperature is lower than 450 ℃ in the 1 st stage, Bi is obtained4O5I instead of Bi5O7I, Bi is sublimated at the temperature higher than 600 ℃, and the synthesis of the material is seriously influenced.
The invention also provides application of the long afterglow-bismuth based nano composite photocatalyst in photocatalytic degradation of agricultural and veterinary drugs.
In one embodiment of the invention, the veterinary drug is selected from tetracycline, chloramphenicol, malachite green, or acid orange.
Compared with the prior art, the technical scheme of the invention has the following advantages:
the method of the invention degrades pollutants such as pesticide and animal medicine in water, Bi5O7The defect-rich ultrathin layer structure of the I contains a large number of non-coordinated surface atoms, more active sites can be exposed than bulk materials, the diffusion length of photogenerated carriers is shorter, and meanwhile, the activity under ultraviolet and visible light is improved due to the existence of iodine vacancies, and the degradation efficiency is further improved. And the separation rate of photon-generated carriers is further improved after the compound with ZnGeO and SrNRs with proper conduction band valence band positions.
Drawings
In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which
FIG. 1 is an SEM photograph of ZnGeO SrNRs in example 1 of the present invention.
FIG. 2 is the ZnGeO long persistence nanorod ZnGeO SrNRs// Bi of example 1 of the present invention5O7SEM image of I composite.
FIG. 3 shows the long persistence nanorod ZnGeO of example 1 of the present invention: SrNRs// Bi5O7XRD pattern of the I composite.
FIG. 4 shows a long afterglow nanorod ZnGeO of the invention5O7The tetracycline degradation condition of the composite material is shown.
Detailed Description
The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.
Example 1
1，Bi5O7Preparation of I: first, 1mM Bi (NO) is taken3)3·5H2O and dispersed homogeneously in 25mL of deionized water without stirring, followed by the addition of 25mL of glycerol (glycerin). Stirring for 30min until the solution is clear and transparent. Followed by5mL of 1mM potassium iodide (KI) was added and stirring was continued for 30 min. The mixed solution was transferred to an 80mL reaction vessel and reacted at 160 ℃ for 6 hours. After the reaction kettle is completely cooled to room temperature, the solid catalyst is centrifugally washed by deionized water and ethanol for many times to remove residual impurities. Finally, the mixture is placed into a 50 ℃ oven for drying for 12 hours to obtain a white solid. The white powder obtained from drying was ground in an agate mortar to achieve homogeneity. Finally, moving the mixture to a tubular furnace, controlling the heating rate at 5 ℃/min, the heat preservation temperature at 500 ℃ and the heat preservation time at 8h, changing the white solid into light yellow, and drying to obtain light yellow solid powder Bi5O7I was ground in an agate mortar to achieve homogeneity.
2, preparing the long afterglow nanorod ZnGeO Sr NRs: 2mmol Zn (NO)3)2,0.01mmol Sr(NO3)2And 300. mu.L of concentrated nitric acid were mixed with vigorous stirring to give a colorless transparent solution. Subsequently, 11mL of ultrapure water was added to the above mixed solution. Finally, 1.5mL of prepared Na was added dropwise thereto2GeO3The solution was adjusted to pH 9 by ammonia. At the same time, the solution changed from clear to transparent to white turbid. The solution is magnetically stirred for 1 hour at room temperature and then transferred into a 25mL hydrothermal reaction kettle, the temperature is kept for 4 hours at 220 ℃, after the solution is naturally cooled to the room temperature, white precipitate at the lower layer is centrifugally collected and repeatedly washed by deionized water and centrifuged (10000rmp/min) for many times. The dried long afterglow nano rod ZnGeO Sr NRs powder is ground in an agate mortar to achieve homogeneity. The resulting material was subjected to structural characterization, and the results are shown in fig. 1.
3，ZnGeO:SrNRs/Bi5O7I preparation of the composite material: the mass ratio of the long afterglow nano rod ZnGeO to Sr NRs to BiOI is controlled to be 10%, 20% and 60%. Weighing a proper amount of long afterglow nano rods ZnGeO, SrNRs and a proper amount of BiOI, grinding in an agate mortar to achieve homogeneity, then transferring into a crucible, directly calcining in air at 500 ℃ for 1h in a tubular furnace at the heating rate of 5 ℃/min, and changing white powder into light yellow solid. The structure of the obtained material is characterized, and the result is shown in figure 2-3, which shows that the long afterglow nano rod is Bi5O7The I nanometer mountains are uniformly distributed and tightly combined.
Example 2
1，Bi5O7Preparation of I: first, 2mM Bi (NO) was taken3)3·5H2O and dispersed homogeneously in 50mL of deionized water without stirring, followed by the addition of 50mL of glycerol (glycerin). Stirring for 30min until the solution is clear and transparent. 10mL of 1mM potassium iodide (KI) was then added and stirring was continued for 30 min. The mixed solution was transferred to a 150mL reaction vessel and reacted at 160 ℃ for 6 hours. After the reaction kettle is completely cooled to room temperature, the solid catalyst is centrifugally washed by deionized water and ethanol for many times to remove residual impurities. Finally, the mixture is placed into a 50 ℃ oven for drying for 12 hours to obtain a white solid. The white powder obtained from drying was ground in an agate mortar to achieve homogeneity. Finally, moving the mixture to a tubular furnace, controlling the heating rate at 5 ℃/min, the heat preservation temperature at 500 ℃ and the heat preservation time at 2h, changing the white solid into light yellow, and drying to obtain light yellow solid powder Bi5O7I was ground in an agate mortar to achieve homogeneity.
2, preparing the long afterglow nanorod ZnGeO Sr NRs: 4mmol Zn (NO)3)2,0.03mmol Sr(NO3)2And 600. mu.L of concentrated nitric acid were mixed with vigorous stirring to give a colorless transparent solution. Then, 22mL of ultrapure water was added to the above mixed solution. Finally, 3mL of prepared Na was added dropwise thereto2GeO3The solution was adjusted to pH 7 with ammonia. At the same time, the solution changed from clear to transparent to white turbid. The solution is magnetically stirred for 1 hour at room temperature and then transferred into a 50mL hydrothermal reaction kettle, the temperature is kept for 2 hours at 220 ℃, after the solution is naturally cooled to the room temperature, white precipitate at the lower layer is centrifugally collected and repeatedly washed by deionized water and centrifuged (10000rmp/min) for many times. The dried long afterglow nano rod ZnGeO Sr NRs powder is ground in an agate mortar to achieve homogeneity.
3，ZnGeO:SrNRs/Bi5O7I preparation of the composite material: the mass ratio of the long afterglow nano rod ZnGeO to Sr NRs to BiOI is controlled to be 10%, 20% and 60%. Weighing appropriate amount of long afterglow nano rod ZnGeO, SrNRs and appropriate amount of BiOI, grinding in agate mortar to homogenize, transferring into crucible, directly placing in air, heating at a rate of 5 deg.C/min in a tube furnaceCalcining at 500 deg.C for 2h to obtain light yellow solid.
Example 3
1，Bi5O7Preparation of I: first, 4mM Bi (NO) is taken3)3·5H2O and dispersed homogeneously in 100mL of deionized water without stirring, followed by the addition of 100mL of glycerol (glycerin). Stirring for 30min until the solution is clear and transparent. 25mL of 1mM potassium iodide (KI) was then added and stirring was continued for 30 min. The mixed solution was transferred to a 275mL reaction vessel and reacted at 160 ℃ for 6 hours. After the reaction kettle is completely cooled to room temperature, the solid catalyst is centrifugally washed by deionized water and ethanol for many times to remove residual impurities. Finally, the mixture is placed into a 50 ℃ oven for drying for 12 hours to obtain a white solid. The white powder obtained from drying was ground in an agate mortar to achieve homogeneity. Finally, moving the mixture to a tubular furnace, controlling the heating rate at 5 ℃/min, the heat preservation temperature at 500 ℃ and the heat preservation time at 4h, changing the white solid into light yellow, and drying to obtain light yellow solid powder Bi5O7I was ground in an agate mortar to achieve homogeneity.
2, preparing the long afterglow nano rod ZnGeO SrNRs: 8mmol Zn (NO)3)2，0.06mmolSr(NO3)2And 1.2mL of concentrated nitric acid were mixed with vigorous stirring to give a colorless transparent solution. Subsequently, 44mL of ultrapure water was added to the above mixed solution. Finally, 6mL of prepared Na was added dropwise thereto2GeO3The solution was adjusted to pH 8 with ammonia. At the same time, the solution changed from clear to transparent to white turbid. The solution is magnetically stirred for 1 hour at room temperature and then transferred into a 80mL hydrothermal reaction kettle, the temperature is kept for 8 hours at 220 ℃, after the solution is naturally cooled to the room temperature, white precipitate at the lower layer is centrifugally collected and repeatedly washed by deionized water and centrifuged (10000rmp/min) for many times. The long afterglow nano rod ZnGeO SrNRs powder obtained by drying is ground in an agate mortar to achieve homogeneity.
3，ZnGeO:SrNRs/Bi5O7I preparation of the composite material: the mass ratio of the long afterglow nano rod ZnGeO to SrNRs to BiOI is controlled to be 10%, 20% and 60%. Weighing appropriate amount of long afterglow nano rod ZnGeO, SrNRs and appropriate amount of BiOI, grinding in agate mortar to homogenize, and rotatingMoving to a crucible, directly calcining in air at 500 ℃ for 4h in a tube furnace at the heating rate of 5 ℃/min, and changing white powder into light yellow solid.
Example 4
1，Bi5O7Preparation of I: first 5mM Bi (NO) was taken3)3·5H2O and dispersed homogeneously in 125mL of deionized water without stirring, followed by addition of 125mL of glycerol (glycerin). Stirring for 30min until the solution is clear and transparent. 40mL of 1mM potassium iodide (KI) was then added and stirring was continued for 30 min. The mixed solution was transferred to a 300mL reaction vessel and reacted at 220 ℃ for 4 hours. After the reaction kettle is completely cooled to room temperature, the solid catalyst is centrifugally washed by deionized water and ethanol for many times to remove residual impurities. Finally, the mixture is placed into a 50 ℃ oven for drying for 12 hours to obtain a white solid. The white powder obtained from drying was ground in an agate mortar to achieve homogeneity. Finally, moving the mixture to a tubular furnace, controlling the heating rate at 2 ℃/min, the heat preservation temperature at 600 ℃, the heat preservation time at 8h, changing the white solid into light yellow, and drying to obtain light yellow solid powder Bi5O7I was ground in an agate mortar to achieve homogeneity.
2, preparing the long afterglow nanorod ZnGeO Sr NRs: 10mmol Zn (NO)3)2,0.1mmolSr(NO3)2And 1.5mL of concentrated nitric acid were mixed with vigorous stirring to give a colorless transparent solution. Subsequently, 55mL of ultrapure water was added to the above mixed solution. Finally, 8mL of prepared Na was added dropwise thereto2GeO3The solution was adjusted to pH 10 with ammonia. At the same time, the solution changed from clear to transparent to white turbid. The solution is magnetically stirred for 1 hour at room temperature and then transferred into a 80mL hydrothermal reaction kettle, the temperature is kept for 12 hours at 220 ℃, after the solution is naturally cooled to the room temperature, white precipitate at the lower layer is centrifugally collected and repeatedly washed by deionized water and centrifuged (10000rmp/min) for many times. The dried long afterglow nano rod ZnGeO Sr NRs powder is ground in an agate mortar to achieve homogeneity.
3，ZnGeO:SrNRs/Bi5O7I preparation of the composite material: the mass ratio of the long afterglow nano rod ZnGeO to Sr NRs to BiOI is controlled to be 10%, 20% and 60%. Weighing a proper amount of long afterglow nano rodSrNRs and a proper amount of BiOI are ground in an agate mortar to achieve homogeneity, then the mixture is transferred into a crucible and directly calcined in the air at the temperature rising rate of 5 ℃/min for 8 hours at the temperature of 500 ℃ in a tubular furnace, and white powder becomes light yellow solid.
Application example
Study of catalytic performance of the composite: the 10mg long afterglow nanorod ZnGeO of ZnGeO SrNRs/Bi prepared in the example 1 is weighed5O7I composite material, dissolved in 30mL of 20mg/L tetracycline. It was first stirred in the dark for 30min to reach adsorption-desorption equilibrium. Samples were then taken every 2min under visible light. The concentration of tetracycline was measured by centrifugation. Samples were taken 9 times in succession and measured for 18 min. Long afterglow nano rod ZnGeO Sr NRs/Bi5O7The composite material I can degrade 60% -80% of tetracycline.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the spirit or scope of the invention.