CN111036252A - Bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst and preparation method and application thereof - Google Patents

Bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst and preparation method and application thereof Download PDF

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CN111036252A
CN111036252A CN201911230893.8A CN201911230893A CN111036252A CN 111036252 A CN111036252 A CN 111036252A CN 201911230893 A CN201911230893 A CN 201911230893A CN 111036252 A CN111036252 A CN 111036252A
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quantum dot
magnetic nano
onion carbon
bismuth tungstate
nano onion
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张卫珂
吴玉程
朱卫中
郭春丽
王佳玮
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Shanxi Zhongxing Environmental And Energy Technology Co ltd
Taiyuan University of Technology
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    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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Abstract

The invention relates to the technical field of photocatalytic materials, in particular to a bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite material photocatalyst and a preparation method and application thereof. According to the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite material photocatalyst provided by the invention, the bismuth tungstate quantum dot is fixed on the surface of the magnetic nano onion carbon through a C-O bond, and the size of the bismuth tungstate quantum dot is 3-10 nm. According to the invention, the bismuth tungstate quantum dots with small sizes are fixed on the surface of the magnetic nano onion carbon through C-O bonds, so that the interaction between the bismuth tungstate quantum dots and the magnetic nano onion carbon is enhanced, the migration of photo-generated electrons can be promoted, and the photocatalyst provided by the invention has high photo-oxidation and photo-reduction capabilities. The embodiment results show that the photocatalyst provided by the invention can effectively improve the degradation effects of cationic pollutant rhodamine B, anionic pollutant methylene blue and nonionic pollutant phenol when irradiated under simulated sunlight.

Description

Bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst and preparation method and application thereof
Technical Field
The invention relates to the technical field of photocatalytic materials, in particular to a bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite material photocatalyst and a preparation method and application thereof.
Background
The remediation of environmental pollutants by heterogeneous photocatalytic materials is currently considered one of the most effective and economical techniques. Among various photocatalysts, Bi2WO6Because of its high stability, nontoxicity, wide sunlight response and excellent photocatalytic performance, it is widely concerned about how to effectively improve Bi2WO6The photocatalytic performance of (A) is a key to promoting industrial application of photocatalysis. Previous studies have shown that increasing the separation efficiency of photogenerated carriers can significantly improve photocatalytic performance.
The average diffusion time of the photogenerated support from the bulk to the surface of the catalyst is determined as follows:
Figure BDA0002303507850000011
where r is the photocatalyst radius and D is the diffusion coefficient of the support. Therefore, the reduction of the particle size can reduce the recombination of photo-generated electrons and holes to a great extent, thereby achieving the purpose of improving the photocatalytic activity. Based on the above analysis, Quantum Dots (QDs) exhibit better photocatalytic performance due to small particles, and can also generate a plurality of charge carriers by using thermal electrons or single photons to improve light energy conversion efficiency. However, since quantum dots have high surface energy, the synthesis of quantum dots requires coating with a surfactant to prevent oxidation and aggregation, which also prevents the quantum dots from contacting with contaminants, making the photocatalyst unable to serve the purpose of effectively degrading the contaminants. Therefore, quantum dots alone are difficult to use as high performance photocatalysts.
In addition, synthesis of semiconductor heterojunction materials has attracted considerable attention in order to increase the separation rate of photogenerated electron-hole pairs. Generally, when two band gap matched semiconductors are coupled to one semiconductor heterojunction, photoinduced electrons are transferred to the Conduction Band (CB) of the semiconductor and photogenerated holes are transferred to the Valence Band (VB) of the other semiconductor due to the potential difference between CB and VB, respectively. However, the redox ability of the transfer light-induced carrier is lower than that of the original light-induced carrier due to the difference of the band positions. Therefore, the development of semiconductor heterojunctions having both high photooxidation and photoreduction capabilities has been a hot spot of research.
Disclosure of Invention
The invention aims to provide a bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst as well as a preparation method and application thereof. The photocatalyst provided by the invention has high photooxidation and photoreduction capabilities, can promote the migration of photo-generated electrons, and has excellent photocatalytic performance.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite material photocatalyst, wherein the bismuth tungstate quantum dot is fixed on the surface of magnetic nano onion carbon through a C-O bond, and the size of the bismuth tungstate quantum dot is 3-10 nm.
The invention also provides a preparation method of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst in the technical scheme, which comprises the following steps:
mixing bismuth nitrate, sodium oleate and water to obtain a first dispersion liquid;
mixing sodium tungstate, magnetic nano onion carbon and water to obtain a second dispersion liquid;
and dropwise adding the second dispersion liquid into the first dispersion liquid, and carrying out hydrothermal reaction to obtain the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst.
Preferably, the using amount ratio of the bismuth nitrate to the sodium oleate to the water is (1-4) mmol: (5-6) mmol: 50 mL.
Preferably, the molar ratio of the bismuth nitrate to the sodium tungstate is (5-6): (0.5-2).
Preferably, the dosage ratio of the sodium tungstate to the magnetic nano onion carbon to the water is (0.5-2) mmol: (5-10) g: 50 mL.
Preferably, the dropping speed is 1-2 mL/min.
Preferably, the temperature of the hydrothermal reaction is 140-180 ℃ and the time is 14-20 h.
Preferably, the hydrothermal reaction further comprises, after the completion of the hydrothermal reaction: carrying out solid-liquid separation on reaction liquid obtained by the hydrothermal reaction, and sequentially washing and drying obtained solid matters to obtain a bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst; the washing detergent is cyclohexane and ethanol.
Preferably, the drying mode is freeze drying, the drying temperature is-60 to-40 ℃, and the drying time is 16 to 20 hours.
The invention also provides the application of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst prepared by the technical scheme or the application of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst prepared by the preparation method in degrading rhodamine B, methylene blue or phenol.
The invention provides a bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite material photocatalyst, wherein the bismuth tungstate quantum dot is fixed on the surface of magnetic nano onion carbon through a C-O bond, and the size of the bismuth tungstate quantum dot is 3-10 nm. According to the photocatalyst provided by the invention, the bismuth tungstate quantum dots with small sizes are fixed on the surface of the magnetic nano onion carbon through C-O bonds, so that the interaction between the bismuth tungstate quantum dots and the magnetic nano onion carbon is enhanced, and the migration of photo-generated electrons can be promoted. The embodiment result shows that the photocatalyst provided by the invention can effectively improve the degradation effects of cationic pollutants rhodamine B (RhB), anionic pollutants Methylene Blue (MB) and nonionic pollutants phenol under the irradiation of simulated sunlight.
The invention also provides a preparation method of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst in the technical scheme, which comprises the following steps: mixing bismuth nitrate, sodium oleate and water to obtain a first dispersion liquid; mixing sodium tungstate, magnetic nano onion carbon and water to obtain a second dispersion liquid; and dropwise adding the second dispersion liquid into the first dispersion liquid, and carrying out hydrothermal reaction to obtain the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst. In the present invention, Bi3+Forming a dioleate complex with sodium oleate through electrostatic interaction, and the process can effectively prevent Bi3+In addition, excessive sodium oleate may interact with the dioleate complex, so that substances in the solution can be uniformly dispersed in a water system; after magnetic nano onion carbon (MCNOs) are added into a reaction system, the dioleate complex is preferentially adsorbed on oxygen-containing functional groups on the surfaces of the MCNOs, and then along with the progress of a hydrothermal reaction, the dioleate complex and WO4 2-Reacting to form bismuth tungstate quantum dots (BWO QDs) in situ on the surface of the MCNOs, wherein the BWO QDs are tightly fixed on the surface of the MCNOs by C-O bonds; MCNOs are a good substrate to effectively prevent BWO QDs from aggregating during the synthesis of BWOQDs. In the present invention, sodium oleate has a dual function, on the one hand, with Bi3+The strong ligand matched with the bismuth tungstate nanometer carbon nano-composite photocatalyst restricts the growth of BWO QDs, so that the magnetic composite photocatalyst with bismuth tungstate quantum dots uniformly and tightly fixed on the surface of the magnetic nano-onion carbon nano-composite photocatalyst is obtained, and the photocatalytic performance is improved.
Drawings
FIG. 1 is a diagram of the mechanism of formation of a bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst provided by the present invention;
FIG. 2 is a TEM image and an HRTEM image of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst prepared in example 1 of the present invention;
FIG. 3 is a diagram of the process of photocatalytic degradation of RhB by different photocatalysts in the dark and under visible light;
FIG. 4 is a UV-VIS spectrum of RhB in the degradation process of RhB using BWO QDs/MCNOs provided in example 1 as a catalyst;
FIG. 5 is a graph showing the effect of different photocatalysts on the photocatalytic degradation of MB and phenol;
FIG. 6 is a diagram showing the photocatalytic degradation rate of the bismuth tungstate quantum dots/magnetic nano onion carbon magnetic composite photocatalyst for degrading RhB after six cycles;
FIG. 7 is a graph showing the degradation process of RhB with different capture agents added during the reaction.
Detailed Description
The invention provides a bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite material photocatalyst, wherein the bismuth tungstate quantum dot is fixed on the surface of magnetic nano onion carbon through a C-O bond, and the size of the bismuth tungstate quantum dot is 3-10 nm, preferably 5-7 nm; the loading amount of the bismuth tungstate quantum dots is preferably 20-25%, and more preferably 25%.
The invention also provides a preparation method of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst in the technical scheme, which comprises the following steps:
mixing bismuth nitrate, sodium oleate and water to obtain a first dispersion liquid;
mixing sodium tungstate, magnetic nano onion carbon and water to obtain a second dispersion liquid;
and dropwise adding the second dispersion liquid into the first dispersion liquid, and carrying out hydrothermal reaction to obtain the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst.
The invention mixes bismuth nitrate, sodium oleate and water to obtain a first dispersion liquid. In the invention, the dosage ratio of the bismuth nitrate, the sodium oleate and the water is preferably (1-4) mmol: (5-6) mmol: 50mL, more preferably 1 mmol: 5.5 mmol: 50 mL. In the present invention, the water is preferably distilled water. In the invention, the mixing is preferably carried out under an ultrasonic condition, and the power of the ultrasonic is preferably 50-60%, and more preferably 55%; the time is preferably 1 to 2 hours, and more preferably 1.5 hours. In the present invention, the first dispersion is preferably an emulsion.
Sodium tungstate, magnetic nano onion carbon and water are mixed to obtain a second dispersion liquid. In the invention, the molar ratio of bismuth nitrate to sodium tungstate is preferably (5-6): (0.5 to 2), and more preferably 5: 1. In the invention, the dosage ratio of the sodium tungstate, the magnetic nano onion carbon and the water is preferably (0.5-2) mmol: (5-10) g: 50mL, more preferably 1 mmol: 5-8 g: 50 mL. In the invention, the mixing is preferably carried out under an ultrasonic condition, and the power of the ultrasonic is preferably 50-70%, more preferably 60%; the time is preferably 20-40 min, and more preferably 30 min. In the present invention, the first dispersion is preferably an emulsion. In the present invention, the second dispersion liquid is preferably a suspension.
After the first dispersion liquid and the second dispersion liquid are obtained, the second dispersion liquid is dropwise added into the first dispersion liquid for hydrothermal reaction, and the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst is obtained. In the invention, the dropping speed is preferably 1-2 mL/min, and more preferably 1.5 mL/min.
After the dropwise addition is finished, the obtained system is preferably subjected to ultrasonic dispersion and stirring in sequence, and then subjected to hydrothermal reaction. In the invention, the power of ultrasonic dispersion is preferably 45-55%, and more preferably 50%; the time is preferably 30-40 min, and more preferably 30 min. In the invention, the stirring time is preferably 1-2 h, and more preferably 2 h.
In the invention, the temperature of the hydrothermal reaction is preferably 140-180 ℃, and more preferably 160 ℃; the time is preferably 14 to 20 hours, and more preferably 18 hours. In the invention, the forming mechanism of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst is shown in figure 1, in the hydrothermal reaction process, a dioleate complex formed by bismuth nitrate and sodium oleate is adsorbed on oxygen-containing functional groups on the surface of MCNOs, and along with the hydrothermal reaction, the dioleate complex and WO are reacted4 2-Reacting to form BWO QDs in situ on the MCNOs surface, wherein the BWO QDs are tightly fixed on the MCNOs surface by C-O bonds; in addition, in the synthesis process of the BWO QDs, the MCNOs can also effectively prevent the BWO QDs from gathering, and finally the photocatalyst with the BWO QDs uniformly dispersed on the surface of the MCNOs is obtained, so that the catalytic performance is improved.
After the hydrothermal reaction is finished, preferably washing and drying the obtained solid substances in sequence to obtain the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst. In the invention, the washing detergent is preferably cyclohexane and ethanol, and the washing process is preferably washing alternately with cyclohexane and absolute ethanol. In the present invention, the drying mode is preferably freeze drying, and the drying temperature is preferably-60 to-40 ℃, and more preferably-55 ℃; the time is preferably 16-20 h, and more preferably 18 h. The invention adopts a freeze drying mode to avoid the agglomeration of BWO QDs.
The invention also provides the application of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst prepared by the technical scheme or the preparation method of the technical scheme in degrading rhodamine B, methylene blue or phenol. The photocatalyst provided by the invention can effectively improve the degradation effects of cationic pollutants rhodamine B (RhB), anionic pollutants Methylene Blue (MB) and nonionic pollutants phenol under the irradiation of simulated sunlight.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Dissolving 1mmol of bismuth nitrate and 5.5mmol of sodium oleate in 50mL of distilled water, and performing ultrasonic dispersion (power is 60% and time is 2 hours) to form uniform emulsion A; dissolving 1mmol of sodium tungstate and 5g of MCNOs in 50mL of distilled water, and performing ultrasonic treatment for 30min under the ultrasonic power of 60% to form a uniform suspension B; dropwise adding the suspension B into the emulsion A at the dropping speed of 2mL/min, carrying out ultrasonic dispersion for 30min, stirring vigorously for 2h, transferring into a polytetrafluoroethylene reaction kettle, and heating at 160 ℃ for 18 h; after the reaction kettle is naturally cooled to room temperature, the reaction kettle is alternately cleaned by cyclohexane and absolute ethyl alcohol and then is subjected to freeze drying at the temperature of minus 55 ℃ for 16 hours to obtain the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst (BWOQDs/MCNOs); the dimension of BWO QDs in the resulting BWO QDs/MCNOs is 8 nm.
Comparative example 1
The procedure was essentially the same as in example 1 except that MCNOs were not added during the preparation.
Test example 1
The TEM and HRTEM images of BWO QDs/MCNOs obtained in example 1 are shown in FIG. 2, wherein (a) in FIG. 2 is the TEM image of BWO QDs/MCNOs, and it can be seen that BWO QDs are distributed more closely and uniformly, and the particle diameter is about 3 nm; FIG. 2 (b) is an HRTEM image of BWO QDs/MCNOs, from which it can be seen that BWO QDs are more clearly defined (dotted circles) and the lattice fringe spacing of BWO QDs is 0.317nm, which is comparable to Bi2WO6The (113) plane is consistent in the orthorhombic system of (a), which demonstrates the formation of BWO QDs; the white part is the lattice stripe of MCNOs, corresponding to the (002) crystal plane of graphite, which proves that BWOQDs can be uniformly dispersed on the surface of MCNOs, and the interaction between BWO QDs and MCNOs is strengthened, and the migration of photo-generated electrons can be promoted.
Test example 2
The effect of BWO QDs/MCNOs provided in example 1 on the photocatalytic degradation of RhB is tested, as shown in FIG. 3, wherein FIG. 3 is the whole degradation process of different photocatalysts on the photocatalytic degradation of RhB in darkness and under visible light; as can be seen from fig. 3, RhB undergoes substantially no degradation reaction under the condition of light irradiation, which demonstrates the stability of RhB; after MCNOs are added into the RhB solution, the absorbance of RhB is only partially reduced in the dark reaction process, because the MCNOs are adsorbed in the dark reaction stage, when the MCNOs reach adsorption balance, the degradation of RhB is basically unchanged under the condition of visible light, which shows that the MCNOs basically have no photocatalytic degradation effect; then, in order to analyze the photocatalytic performance of the BWO QDs/MCNOs and the BWO QDs, the BWO QDs prepared in example 1 and the BWO QDs prepared in comparative example 1 are respectively added into a RhB solution, a reaction system is placed in a photocatalytic reaction box after uniform ultrasonic dispersion, after 2h, the degradation of the RhB by the BWO QDs/MCNOs is basically finished, and the degradation rate of the RhB by the BWO QDs/MCNOs is only 50 percent and is far lower than that of the RhB by a BWO QDs/MCNOs composite material.
FIG. 4 is the UV-Vis spectrum of RhB in the degradation process of RhB using BWO QDs/MCNOs provided in example 1 as catalyst, and the inset shows the color change of RhB in the photocatalytic degradation process; as can be seen from fig. 4, the main absorption peak of RhB is shifted from 554nm to 496nm, and a significant decrease in RhB absorbance is observed due to the demethylation process of RhB during degradation, indicating that the degradation of RhB by BWO QDs/MCNOs is a chemical process rather than an adsorption process, and the rapid decrease in RhB absorbance is due to bond cleavage of RhB, and is degraded into small molecules.
Test example 3
The effect of BWO QDs/MCNOs provided in example 1 and BWO QDs provided in comparative example 1 on the photocatalytic degradation of MB and phenol was tested, as shown in FIG. 5, wherein (a) in FIG. 5 is a graph of the degradation effect of MB and (b) in FIG. 5 is a graph of the degradation effect of phenol.
As can be seen from FIG. 5, after the simulated sunlight irradiates for 1h, the degradation rates of BWO QDs/MCNOs and BWO QDs to MB reach 99% and 65% respectively, which proves that the photocatalytic performance of BWO QDs/MCNOs is improved; in addition, in order to eliminate the influence of photosensitization of the colored dye, phenol solution is used as a target pollutant to evaluate the photocatalytic performance of the material, and after 2h of sunlight irradiation, the degradation rates of BWO QDs/MCNOs and BWO QDs on phenol reach 91% and 62%, respectively, which also proves the improvement of the photocatalytic performance of the BWO QDs/MCNOs.
Test example 4
In order to research the stability and long-term performance of BWO QDs/MCNOs under simulated sunlight irradiation, in the same BWO QDs/MCNOs sample, the degradation of RhB is subjected to six times of photocatalysis; the BWO QDs/MCNOs sample after each degradation reaction is cleaned by ultrasonic waves in ethanol and dried for subsequent photoreaction cycles, as shown in FIG. 6, and as can be seen from FIG. 6, the photocatalytic degradation rate of RhB is reduced from the first cycle to the third cycle, and the degradation efficiency is increased from the fourth cycle; one reason for this increase in photocatalytic activity may be that, as the photocatalytic reaction proceeds, the oleic acid ions on the surface of BWO QDs/MCNOs are photocatalytically eliminated, thereby increasing the active sites for degrading and adsorbing contaminants; another reason for the improved photocatalytic activity may be that MCNOs in the photocatalyst are further reduced during the photocatalytic process, which may increase the electrical conductivity of MCNOs and improve the photocatalytic activity.
Test example 5
In order to research the photocatalytic degradation mechanism of BWO QDs/MCNOs degrading organic pollutants under visible light, different capture agents are adopted to research active substances in the experiment, and EDTA-2Na is used for capturing hvb+Isopropyl alcohol (IPA) trapping-OH free radical, Benzoquinone (BQ) trapping-O2 -FIG. 7 shows the different degradation effects of the photocatalyst on RhB after addition of the capture agent; as can be seen from FIG. 7, the photocatalytic degradation effect is less changed after IPA is added, which indicates that the degradation effect of OH active groups on organic matters is less; in contrast, the addition of EDTA-2Na greatly inhibited the photocatalytic degradation process, indicating that the reactive group hvb+Plays a leading role in the photocatalytic degradation process of organic matters; in addition, the degradation rate was slightly decreased after BQ was added to the organic solution, indicating that O2 -Is another active substance that acts on photocatalytic degradation. Thus, these results demonstrate hvb+And O2 -The combined action of the composite material is the key action of the composite material in performing photocatalytic degradation on organic matters.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. The bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite material photocatalyst is characterized in that the bismuth tungstate quantum dot is fixed on the surface of magnetic nano onion carbon through a C-O bond, and the size of the bismuth tungstate quantum dot is 3-10 nm.
2. The preparation method of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst as claimed in claim 1, which is characterized by comprising the following steps:
mixing bismuth nitrate, sodium oleate and water to obtain a first dispersion liquid;
mixing sodium tungstate, magnetic nano onion carbon and water to obtain a second dispersion liquid;
and dropwise adding the second dispersion liquid into the first dispersion liquid, and carrying out hydrothermal reaction to obtain the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst.
3. The preparation method according to claim 2, wherein the ratio of the amounts of bismuth nitrate, sodium oleate and water in the first dispersion is (1-4) mmol: (5-6) mmol: 50 mL.
4. The preparation method according to claim 2, wherein the molar ratio of the bismuth nitrate to the sodium tungstate is (5-6): (0.5-2).
5. The preparation method according to claim 2 or 4, wherein the amount ratio of the sodium tungstate to the magnetic nano onion carbon to the water in the second dispersion liquid is (0.5 to 2) mmol: (5-10) g: 50 mL.
6. The method according to claim 2, wherein the dropping is performed at a rate of 1 to 2 mL/min.
7. The preparation method according to claim 2, wherein the hydrothermal reaction is carried out at a temperature of 140 to 180 ℃ for 14 to 20 hours.
8. The preparation method according to claim 2, further comprising, after the hydrothermal reaction is completed: carrying out solid-liquid separation on reaction liquid obtained by the hydrothermal reaction, and sequentially washing and drying obtained solid matters to obtain a bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst; the washing detergent is cyclohexane and ethanol.
9. The preparation method according to claim 8, wherein the drying mode is freeze drying, the drying temperature is-60 to-40 ℃, and the drying time is 16 to 20 hours.
10. The application of the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst described in claim 1 or the bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst prepared by the preparation method described in claims 2-9 in degrading rhodamine B, methylene blue or phenol.
CN201911230893.8A 2019-12-05 2019-12-05 Bismuth tungstate quantum dot/magnetic nano onion carbon magnetic composite photocatalyst and preparation method and application thereof Pending CN111036252A (en)

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