阅读说明：本技术 铁酸锌/钨酸铋复合催化剂及其制备方法与在废气处理方面的应用 (Zinc ferrite/bismuth tungstate composite catalyst, preparation method thereof and application thereof in waste gas treatment ) 是由 路建美 陈冬赟 于 2019-11-08 设计创作，主要内容包括：本发明公开了铁酸锌/钨酸铋复合催化剂及其制备方法与在废气处理方面的应用；以六水合硝酸锌(Zn(NO<Sub>3</Sub>)<Sub>2</Sub>·6H<Sub>2</Sub>O),九水合硝酸铁(Fe(NO<Sub>3</Sub>)<Sub>3</Sub>·9H<Sub>2</Sub>O)聚乙烯吡咯烷酮(PVP,K90)为原料,并以N,N-二甲基甲酰胺(DMF)为溶剂,通过静电纺丝和高温煅烧法制备铁酸锌(ZnFe<Sub>2</Sub>O<Sub>4</Sub>)纳米纤维；以五水硝酸铋(Bi(NO<Sub>3</Sub>)<Sub>3</Sub>·5H<Sub>2</Sub>O)和二水钨酸钠(Na<Sub>2</Sub>WO<Sub>6</Sub>·2H<Sub>2</Sub>O)为铋源和钨源,将其溶解在无水乙醇(Ethanol)和乙二醇(Ethylene glycol)的混合溶剂中,再将ZnFe<Sub>2</Sub>O<Sub>4</Sub>纳米纤维加入上述混合溶液中,通过加热反应制备Bi<Sub>2</Sub>WO<Sub>6</Sub>纳米片生长在ZnFe<Sub>2</Sub>O<Sub>4</Sub>纳米纤维,得到ZnFe<Sub>2</Sub>O<Sub>4</Sub>/Bi<Sub>2</Sub>WO<Sub>6</Sub>纳米复合材料,为铁酸锌/钨酸铋复合催化剂。本发明ZnFe<Sub>2</Sub>O<Sub>4</Sub>/Bi<Sub>2</Sub>WO<Sub>6</Sub>纳米复合光催化剂促进了Bi<Sub>2</Sub>WO<Sub>6</Sub>和ZnFe<Sub>2</Sub>O<Sub>4</Sub>两者中光生载流子的分离效率,有效地增加光生电荷的存活寿命,促进其光催化活性。(The invention discloses a zinc ferrite/bismuth tungstate composite catalyst, a preparation method thereof and application thereof in waste gas treatment; with zinc nitrate hexahydrate (Zn (NO) 3 ) 2 ·6H 2 O), iron nitrate nonahydrate (Fe (NO) 3 ) 3 ·9H 2 O) polyvinylpyrrolidone (PVP, K90) as raw material, N-Dimethylformamide (DMF) as solvent, electrostatic spinning and high-temperature calcining to prepare zinc ferrite (ZnF)e 2 O 4 ) A nanofiber; with bismuth nitrate pentahydrate (Bi (NO) 3 ) 3 ·5H 2 O) and sodium tungstate dihydrate (Na) 2 WO 6 ·2H 2 O) is a bismuth source and a tungsten source, and is dissolved in a mixed solvent of absolute ethyl alcohol (Ethanol) and Ethylene glycol (Ethylene glycol), and ZnFe is added 2 O 4 Adding the nano-fiber into the mixed solution, and preparing Bi through heating reaction 2 WO 6 The nanosheet grows on ZnFe 2 O 4 Nanofibers to obtain ZnFe 2 O 4 /Bi 2 WO 6 The nano composite material is a zinc ferrite/bismuth tungstate composite catalyst. ZnFe of the invention 2 O 4 /Bi 2 WO 6 The nano composite photocatalyst promotes Bi 2 WO 6 And ZnFe 2 O 4 The separation efficiency of the photo-generated carriers in the two materials effectively prolongs the survival life of the photo-generated charges and promotes the photocatalytic activity of the photo-generated charges.)

1. The zinc ferrite/bismuth tungstate composite catalyst is characterized in that the preparation method of the zinc ferrite/bismuth tungstate composite catalyst comprises the following steps of mixing ZnFe₂O₄Adding the nano-fiber into a solution containing bismuth salt and tungsten salt, and heating for reaction to obtain the zinc ferrite/bismuth tungstate composite catalyst.

2. The zinc ferrite/bismuth tungstate composite catalyst as claimed in claim 1, wherein the ZnFe is prepared by spinning and calcining a solution containing zinc salt and iron salt as a spinning solution₂O₄And (3) nano fibers.

3. The zinc ferrite/bismuth tungstate composite catalyst as claimed in claim 2, wherein the spinning solution is composed of zinc salt, iron salt, binder and solvent; the spinning is electrostatic spinning; the calcining temperature is 500-800 ℃, and the time is 1-3 h.

4. The zinc ferrite/bismuth tungstate composite catalyst as claimed in claim 2, wherein the ratio of the zinc salt to the iron salt to the binder is (0.5-5) mmol to (1-10) g; the voltage of electrostatic spinning is 10-20 kV, and the injection speed is 0.15-0.25 mm/min; the zinc salt is zinc nitrate hexahydrate, the ferric salt is ferric nitrate nonahydrate, and the adhesive is polyvinylpyrrolidone.

5. The zinc ferrite/bismuth tungstate composite catalyst as claimed in claim 1, wherein the mass ratio of the bismuth salt to the tungsten salt is (100-500) to (10-100); the heating reaction temperature is 30-200 ℃, and the time is 12-48 h.

6. The zinc ferrite/bismuth tungstate composite catalyst as claimed in claim 1, wherein the bismuth salt, the tungsten salt, and the ZnFe salt are used as the catalyst₂O₄The mass ratio of the nano fibers is 6: 2: 0.6-1.5.

7. The zinc ferrite/bismuth tungstate composite catalyst as claimed in claim 1, wherein the bismuth salt is bismuth nitrate pentahydrate, and the tungsten salt is sodium tungstate dihydrate; in the solution containing bismuth salt and tungsten salt, the solvent is a mixed solvent of absolute ethyl alcohol and glycol.

8. The use of the zinc ferrite/bismuth tungstate composite catalyst as set forth in claim 1 for the treatment of exhaust gas.

9. Use according to claim 8, wherein the exhaust gas is a nitride.

10. The preparation method of the zinc ferrite/bismuth tungstate composite catalyst is characterized by comprising the following steps of mixing ZnFe₂O₄The nano-fiber is added with a solution containing bismuth salt and tungsten saltIn the solution, heating and reacting to obtain the zinc ferrite/bismuth tungstate composite catalyst.

Technical Field

The invention belongs to the technical field of inorganic functional materials, and particularly relates to zinc ferrite/bismuth tungstate (ZnFe)₂O₄/Bi₂WO₆) A preparation method of the composite catalyst and application of the composite catalyst to the aspect of waste gas treatment.

Background

With the rapid development of social economy and industrialization, the pollution of industrial exhaust gas is increasingly serious, and great harm is brought to human beings, animals and plants. In addition, the exhaust gas causes environmental pollution such as acid rain, acid mist and photochemical smog. Therefore, the search for a cheap, efficient and energy-saving method for degrading and treating the waste gas has become a hot problem of environmental research. At present, the semiconductor photocatalysis technology has the advantages of no toxicity, high degradation efficiency, strong oxidation-reduction capability and the like, and is considered to be one of the most economic and effective methods for treating waste gas pollution. Among the many photocatalysts currently available, Bi₂WO₆Is an oxide semiconductor photocatalyst which has been widely studied, however, Bi₂WO₆Also have their own deficiencies such as the easy and rapid recombination of photogenerated electrons and holes upon illumination. Therefore, it is necessary to develop a new method for Bi₂WO₆Different modification modes are carried out, so that the photocatalytic activity is further improved.

Disclosure of Invention

The invention aims to provide a nano composite material ZnFe capable of responding to visible light₂O₄/Bi₂WO₆And a method for preparing the same andvisible light photocatalytic degradation of exhaust gas. Adding Bi₂WO₆The nanosheet photocatalyst is modified to ZnFe through solvothermal mode₂O₄On the nano-fiber to obtain ZnFe₂O₄/Bi₂WO₆The nano composite material is used for carrying out photocatalytic degradation on the waste gas so as to effectively treat the waste gas.

In order to achieve the purpose, the specific technical scheme of the invention is as follows:

the preparation method of the zinc ferrite/bismuth tungstate composite catalyst comprises the following steps of mixing ZnFe₂O₄Adding the nano-fiber into a solution containing bismuth salt and tungsten salt, and heating for reaction to obtain the zinc ferrite/bismuth tungstate composite catalyst.

The invention also discloses a method for treating the waste gas by photocatalysis, which comprises the following steps: ZnFe is mixed with water₂O₄Adding the nano-fiber into a solution containing bismuth salt and tungsten salt, and heating for reaction to obtain a zinc ferrite/bismuth tungstate composite catalyst; then the gas containing the waste gas passes through a zinc ferrite/bismuth tungstate composite catalyst to be irradiated by light, so as to realize the photocatalytic treatment of the waste gas.

In the invention, a solution containing zinc salt and iron salt is used as a spinning solution, and ZnFe is prepared by spinning and calcining₂O₄And (3) nano fibers. Preferably, the spinning solution consists of zinc salt, iron salt, an adhesive and a solvent; preferably, the spinning is electrospinning.

In the technical scheme, the using amount ratio of the zinc salt, the ferric salt and the adhesive is (0.5-5) mmol, (1-5) mmol and (1-10) g; the voltage of electrostatic spinning is 10-20 kV, and the injection speed is 0.15-0.25 mm/min; the calcining temperature is 500-800 ℃, and the time is 1-3 h.

In the technical scheme, the mass ratio of the bismuth salt to the tungsten salt is (100-500) to (10-100); the heating reaction temperature is 30-200 ℃, and the time is 12-48 h.

In the technical scheme, bismuth salt, tungsten salt and ZnFe₂O₄The mass ratio of the nano fibers is 6: 2: 0.6-1.5.

In the invention, zinc salt is zinc nitrate hexahydrate, ferric salt is ferric nitrate nonahydrate, adhesive is polyvinylpyrrolidone, and solvent is N, N-dimethylformamide; the bismuth salt is bismuth nitrate pentahydrate, and the tungsten salt is sodium tungstate dihydrate; in the solution containing bismuth salt and tungsten salt, the solvent is a mixed solvent of absolute ethyl alcohol (Ethanol) and Ethylene glycol (Ethylene glycol).

The preparation method of the zinc ferrite/bismuth tungstate composite catalyst comprises the following steps:

(1) with zinc nitrate hexahydrate (Zn (NO)₃)₂·6H₂O), iron nitrate nonahydrate (Fe (NO)₃)₃·9H₂O) polyvinylpyrrolidone (PVP, K90) as raw material, N-Dimethylformamide (DMF) as solvent, electrostatic spinning and high-temperature calcining to prepare zinc ferrite (ZnFe)₂O₄) A nanofiber;

(2) with bismuth nitrate pentahydrate (Bi (NO)₃)₃·5H₂O) and sodium tungstate dihydrate (Na)₂WO₆·2H₂O) is a bismuth source and a tungsten source, and is dissolved in a mixed solvent of absolute ethyl alcohol (Ethanol) and Ethylene glycol (Ethylene glycol), and ZnFe is added₂O₄Adding the nano-fiber into the mixed solution, and preparing Bi through heating reaction₂WO₆The nanosheet grows on ZnFe₂O₄Nanofibers to obtain ZnFe₂O₄/Bi₂WO₆The nano composite material is a zinc ferrite/bismuth tungstate composite catalyst.

The invention discloses a method for treating waste gas by photocatalysis, which comprises the following steps:

(1) with zinc nitrate hexahydrate (Zn (NO)₃)₂·6H₂O), iron nitrate nonahydrate (Fe (NO)₃)₃·9H₂O) polyvinylpyrrolidone (PVP, K90) as raw material, N-Dimethylformamide (DMF) as solvent, electrostatic spinning and high-temperature calcining to prepare zinc ferrite (ZnFe)₂O₄) A nanofiber;

(2) with bismuth nitrate pentahydrate (Bi (NO)₃)₃·5H₂O) and sodium tungstate dihydrate (Na)₂WO₆·2H₂O) is a bismuth source and a tungsten source, and is dissolved in a mixed solvent of absolute ethyl alcohol (Ethanol) and Ethylene glycol (Ethylene glycol), and ZnFe is added₂O₄Adding the nano-fiber into the mixed solution, and preparing Bi through heating reaction₂WO₆The nanosheet grows on ZnFe₂O₄Nanofibers to obtain ZnFe₂O₄/Bi₂WO₆The nano composite material is a zinc ferrite/bismuth tungstate composite catalyst;

(3) and (3) allowing the gas containing the waste gas to flow through the zinc ferrite/bismuth tungstate composite catalyst, and illuminating to realize the photocatalytic treatment of the waste gas.

The invention also discloses the application of the zinc ferrite/bismuth tungstate composite catalyst in waste gas treatment.

In the invention, the waste gas is nitric oxide, and the light irradiation is visible light irradiation.

The visible light responding nano composite material ZnFe of the invention₂O₄/Bi₂WO₆The preparation method of (a) can be carried out as follows:

1.ZnFe₂O₄preparation of nanofibers

First, Zn (NO) is added₃)₂·6H₂O and Fe (NO)₃)₃·9H₂O is dissolved in DMF solution. After stirring at room temperature for several hours, PVP was added to the solution and the mixture was continuously magnetically stirred for several hours to give a reddish-brown homogeneous precursor solution. The precursor solution was then transferred to a plastic syringe fitted with a steel needle for electrospinning. Finally, calcining the obtained nano-fiber in the air to obtain ZnFe₂O₄And (3) nano fibers.

2. ZnFe₂O₄/Bi₂WO₆Preparation of composite materials

First, bismuth nitrate pentahydrate and sodium tungstate dihydrate were ultrasonically dissolved in ethylene glycol. Then, ethanol was slowly added to the mixed solvent. Then preparing ZnFe₂O₄The nano-fiber is added and mixed evenly under the stirring condition. Finally transferring the obtained solution into a reaction kettle for heating reaction, and centrifugally washing a solid productObtaining ZnFe₂O₄/Bi₂WO₆A composite material.

3. Photocatalytic degradation of exhaust gas

The operation of photocatalytic degradation of heavy metal wastewater is specifically as follows, ZnFe is researched under the same concentration₂O₄、Bi₂WO₆And a series of ZnFe₂O₄/Bi₂WO₆(100 mg) degradation effect on exhaust gas.

The scheme has the advantages that:

1. the invention adopts easy-to-operate electrostatic spinning and solvothermal method to prepare ZnFe₂O₄/Bi₂WO₆The composite photocatalyst has simple preparation process and low cost of raw materials, is beneficial to reducing the preparation cost and is easy to realize large-scale production.

2. ZnFe of the invention₂O₄/Bi₂WO₆The nano composite photocatalyst promotes Bi₂WO₆And ZnFe₂O₄The separation efficiency of the photo-generated carriers in the two materials effectively prolongs the survival life of the photo-generated charges and promotes the photocatalytic activity of the photo-generated charges.

3. ZnFe obtained by the invention₂O₄/Bi₂WO₆The nano composite material can improve the absorption and utilization of visible light and can effectively carry out photocatalytic degradation on waste gas.

Drawings

FIG. 1 is ZnFe₂O₄Scanning Electron Micrographs (SEM) of nanofibers;

FIG. 2 is ZnFe₂O₄Transmission Electron Microscopy (TEM) of nanofibers;

FIG. 3 is ZnFe₂O₄/Bi₂WO₆Scanning Electron Micrographs (SEM) of the composite;

FIG. 4 shows flower-like Bi₂WO₆Scanning Electron Micrographs (SEM) of the material;

FIG. 5 is ZnFe₂O₄、Bi₂WO₆And ZnFe₂O₄/Bi₂WO₆A catalytic effect graph of the complex;

FIG. 6 is ZnFe₂O₄/Bi₂WO₆Cyclic degradation profile of composite material.

Detailed Description

The preparation method of the zinc ferrite/bismuth tungstate composite catalyst comprises the following steps of mixing ZnFe₂O₄Adding the nano-fiber into a solution containing bismuth salt and tungsten salt, and heating for reaction to obtain the zinc ferrite/bismuth tungstate composite catalyst.

The present invention will be further described with reference to the following examples.