photo-Fenton catalyst and preparation method and application thereof

文档序号：1725613 发布日期：2019-12-20 浏览：31次中文

阅读说明：本技术 一种光芬顿催化剂及其制备方法与应用 (photo-Fenton catalyst and preparation method and application thereof ) 是由黄在银邱江源刘锦萍黄慧婷于 2019-09-30 设计创作，主要内容包括：本发明提供了一种光芬顿催化剂及其制备方法与应用,属于催化剂制备技术领域。本发明提供的光芬顿催化剂包括：均相碳掺杂Bi3Cl4O半导体光催化剂、还原石墨烯和杂多酸铁；所述杂多酸铁原位负载在所述还原石墨烯表面形成复合体；所述均相碳掺杂Bi3Cl4O半导体光催化剂负载在所述复合体上。本发明光芬顿催化剂利用均相碳掺杂Bi3Cl4O受光激发后产生的电子可及时地传递至还原石墨烯表面,进一步与还原石墨烯表面的杂多酸铁反应,将杂多酸铁表面的Fe3+还原为Fe2+促进多相芬顿催化体系中H2O2的分解产生羟基自由基降解污染物。实施例的数据表明：光芬顿催化剂光催化2h内,污染物的降解率均在90％以上。(The invention provides a photo-Fenton catalyst and a preparation method and application thereof, belonging to the technical field of catalyst preparation. The photo-Fenton catalyst provided by the invention comprises: homogeneous carbon-doped Bi 3 Cl 4 O semiconductor photocatalyst and reduced grapheneAnd iron heteropoly acid; the heteropoly acid iron is loaded on the surface of the reduced graphene in situ to form a complex; the homogeneous carbon-doped Bi 3 Cl 4 An O semiconductor photocatalyst is supported on the composite. The photo-Fenton catalyst utilizes homogeneous carbon doped Bi 3 Cl 4 Electrons generated after the O is excited by light can be timely transferred to the surface of the reduced graphene and further react with the heteropoly acid iron on the surface of the reduced graphene to remove Fe on the surface of the heteropoly acid iron 3+ Reduction to Fe 2+ Promotion of H in heterogeneous Fenton catalytic system 2 O 2 The decomposition of (a) produces hydroxyl radicals to degrade the contaminants. The data of the examples show that: the degradation rate of pollutants is over 90% within 2h of photocatalysis of the photo-Fenton catalyst.)

1. A photo-fenton catalyst, comprising: homogeneous carbonDoping with Bi₃Cl₄O semiconductor photocatalyst, reduced graphene and iron heteropoly acid; the heteropoly acid iron is loaded on the surface of the reduced graphene in situ to form a complex; the homogeneous carbon-doped Bi₃Cl₄An O semiconductor photocatalyst is supported on the composite.

2. The photo-Fenton catalyst according to claim 1, wherein the reduced graphene is of homogeneous carbon doped Bi by mass₃Cl₄10.0-50.0% of the O semiconductor photocatalyst.

3. A photo-fenton catalyst according to claim 1 or 2, wherein the mass of the iron heteropoly acid is 10 to 30% of the mass of the reduced graphene.

4. A photo-fenton catalyst according to claim 1 or 2, wherein the mass of the iron element in the iron heteropoly acid is 1 to 20% of the mass of the reduced graphene.

5. A method for preparing the photo-Fenton catalyst according to any one of claims 1 to 4, comprising the steps of:

providing homogeneous carbon-doped Bi₃Cl₄O semiconductor photocatalyst and reduced graphene;

under the condition that the pH value is 1-3, mixing the reduced graphene, an iron source, sodium dodecaphosphotungstate and water, and carrying out a composite reaction to obtain a reduced graphene loaded heteropoly acid iron complex;

loading the reduced graphene with a heteropoly acid iron complex and homogeneous phase carbon-doped Bi₃Cl₄And dispersing the O semiconductor photocatalyst in an N, N-dimethylformamide aqueous solution, and carrying out chemical self-assembly to obtain the photo-Fenton catalyst.

6. The preparation method according to claim 5, wherein the temperature of the composite reaction is room temperature, and the time is 16-18 h.

7. The preparation method according to claim 5, wherein the concentration of the reduced graphene-supported iron heteropoly acid complex in the aqueous N, N-dimethylformamide solution is 0.1-2 mg/mL.

8. The method according to claim 5 or 7, wherein the homogeneous carbon-doped Bi₃Cl₄The concentration of the O semiconductor photocatalyst in the N, N-dimethylformamide aqueous solution is 0.1-5 mg/mL.

9. The preparation method according to claim 5, wherein the temperature of the chemical self-assembly is room temperature and the time is 6-12 h.

10. Use of the photo-Fenton catalyst according to any one of claims 1 to 4 or the photo-Fenton catalyst obtained by the preparation method according to any one of claims 5 to 9 for promoting decomposition of hydrogen peroxide to generate hydroxyl radicals to degrade pollutants.

Technical Field

The invention relates to the technical field of preparation of photocatalytic materials, in particular to a photo-Fenton catalyst and a preparation method and application thereof.

Background

With the rapid development of society, the environmental problems become more serious, and become a main factor for restricting the sustainable development of human society. Therefore, the development of environment-friendly, efficient, low-cost and green pollution control technology, and the design and development of high-performance catalysts for efficiently degrading environmental pollutants have become research hotspots.

The traditional Fenton system has narrow pH range, is easy to form ion precipitation to cause secondary pollution and H₂O₂The concentration is high, so that the problems of serious corrosion of equipment and the like exist; the multiphase Fenton catalytic system has the defects of few catalytic active sites, low catalytic efficiency, usually needs additional energy or combination of technical methods such as chemical reagent assistance and the like, has high requirements on equipment and is difficult to directly apply in a large scale in practice.

Disclosure of Invention

In view of the above, the present invention provides a photo-fenton catalyst, a preparation method thereof and an application thereof. The homogeneous carbon-doped Bi in the photo-Fenton catalyst provided by the invention₃Cl₄Electrons generated by the photo-excitation of the O semiconductor photocatalyst migrate to the surface of the heteropoly acid iron to remove Fe on the surface³⁺Conversion to Fe²⁺For decomposing H₂O₂The generated hydroxyl free radicals degrade pollutants, and the pollutant degradation efficiency is improved.

In order to achieve the above object, the present invention provides the following technical solutions:

the present invention provides a photo-Fenton catalyst, including: homogeneous carbon-doped Bi₃Cl₄O semiconductor photocatalyst, reduced graphene and iron heteropoly acid; the heteropoly acid iron is loaded on the surface of the reduced graphene in situ to form a complex; the homogeneous carbon-doped Bi₃Cl₄An O semiconductor photocatalyst is supported on the composite.

Preferably, the mass of the reduced graphene is homogeneous carbon-doped Bi₃Cl₄10.0-50.0% of the O semiconductor photocatalyst.

Preferably, the mass of the heteropoly acid iron is 10-30% of the mass of the reduced graphene.

Preferably, the mass of the iron element in the heteropoly acid iron is 1-20% of the mass of the reduced graphene.

The invention also provides a preparation method of the photo-Fenton catalyst, which comprises the following steps:

providing homogeneous carbon-doped Bi₃Cl₄O semiconductor photocatalyst and reduced graphene;

Preferably, the temperature of the composite reaction is room temperature, and the time is 16-18 h.

Preferably, the concentration of the reduced graphene-loaded iron heteropoly acid complex in the N, N-dimethylformamide aqueous solution is 0.1-2 mg/L.

Preferably, the homogeneous carbon-doped Bi₃Cl₄The concentration of the O semiconductor photocatalyst in the N, N-dimethylformamide aqueous solution is 0.1-5 mg/L.

Preferably, the temperature of the chemical self-assembly is room temperature, and the time is 6-12 h.

The invention also provides an application of the photo-Fenton catalyst in the technical scheme or the photo-Fenton catalyst obtained by the preparation method in the technical scheme in promoting the decomposition of hydrogen peroxide to generate hydroxyl radicals to degrade pollutants.

The present invention provides a photo-Fenton catalyst, including: homogeneous carbon-doped Bi₃Cl₄O semiconductor photocatalyst, reduced graphene and iron heteropoly acid; the heteropoly acid iron is loaded on the surface of the reduced graphene in situ to form a complex; the homogeneous carbon-doped Bi₃Cl₄An O semiconductor photocatalyst is supported on the composite. The photo-Fenton catalyst utilizes homogeneous carbon doped Bi₃Cl₄Electrons generated after the O is excited by light can be timely transferred to the surface of the reduced graphene and further react with the heteropoly acid iron on the surface of the reduced graphene to remove Fe on the surface of the heteropoly acid iron³⁺Reduction to Fe²⁺Promotion of H in heterogeneous Fenton catalytic system₂O₂The decomposition of (a) produces hydroxyl radicals to degrade the contaminants. The data of the examples show that: the degradation rate of pollutants is over 90% within 2h of photocatalysis of the photo-Fenton catalyst provided by the invention; after the material is recycled for 5 times, the degradation rate of the material on pollutants is still over 90 percent.

The invention also provides a preparation method of the photo-Fenton catalyst, which is simple to operate and can be used for successfully preparing the photo-Fenton catalyst.

The invention also provides application of the photo-Fenton catalyst in the technical scheme in promoting decomposition of hydrogen peroxide to generate hydroxyl radicals to degrade pollutants. The photo-Fenton catalyst can promote the decomposition of hydrogen peroxide under illumination, so that the degradation efficiency of organic matters is improved; and the condition for promoting the decomposition of the hydrogen peroxide is simple, and only illumination is needed.

Drawings

FIG. 1 shows Bi obtained in example 1₃Cl₄O and Bi₃Cl₄XRD patterns of O @ RGO @ POMs photo-Fenton catalysts;

FIG. 2 shows Bi obtained in example 1₃Cl₄O (a) and Bi₃Cl₄SEM spectrum of O @ RGO @ POMs photo-Fenton catalyst (b);

FIG. 3 shows Bi in example 1₃Cl₄O, RGO @ POMs and Bi₃Cl₄A graph of the degradation effect of the O @ RGO @ POMs photo-Fenton catalyst on rhodamine B (RhB);

FIG. 4 shows Bi obtained in example 1₃Cl₄A graph of the degradation effect of O @ RGO @ POMs photo-Fenton catalyst on rhodamine B (RhB), Methylene Blue (MB), Methyl Orange (MO) and p-nitrophenol (PNP);

FIG. 5 shows Bi obtained in example 1₃Cl₄Graph of the cyclic degradation effect of O @ RGO @ POMs photo-Fenton catalyst.

Detailed Description

The photo-Fenton catalyst provided by the invention comprises homogeneous carbon-doped Bi₃Cl₄An O semiconductor photocatalyst; the homogeneous carbon-doped Bi₃Cl₄The O semiconductor photocatalyst is preferably in the form of a nanosheet. The homogeneous phase carbon-doped Bi of the invention₃Cl₄The O semiconductor photocatalyst can generate electrons under the excitation of light, and the generated electrons can enable Fe in the heteropoly acid iron³⁺Conversion to Fe²⁺. The invention dopes the homogeneous carbon with Bi₃Cl₄The source of the O semiconductor photocatalyst is not particularly limited and may be prepared by a preparation method well known to those skilled in the art.

In a specific embodiment of the invention, the homogeneous carbon is doped with Bi₃Cl₄The O semiconductor photocatalyst is preferably prepared by the following steps:

placing 6mmol glucose and 2mmol bismuth nitrate pentahydratePutting into a mortar, and grinding for 30min in a dry atmosphere; slowly adding the mixture into 100mL of deionized water under the assistance of ultrasound to obtain a clear mixed solution; then adding 2mmol of potassium oxide into the mixed solution, regulating the pH value of the solution to 10.6 by ammonia water, and then putting the solution into a 100mL high-temperature stainless steel reaction kettle lined with tetrafluoroethylene for hydrothermal reaction at 160 ℃ for 18h to obtain carbon-modified Bi₃Cl₄O; carbon-modified Bi₃Cl₄The O is thermally calcined for 6 hours at the temperature of 450 ℃, and the homogeneous phase carbon-doped Bi can be prepared₃Cl₄And (3) O nanosheet.

The photo-Fenton catalyst provided by the invention comprises reduced graphene; in the invention, the reduced graphene is preferably homogeneous carbon-doped Bi in quality₃Cl₄10.0 to 50.0% by mass of the O semiconductor photocatalyst, more preferably 20.0 to 40.0% by mass, and still more preferably 30.0% by mass. In the present invention, the reduced graphene is doped as homogeneous phase Bi₃Cl₄The carrier of the O semiconductor photocatalyst and the heteropoly acid iron can load the semiconductor photocatalyst on the carrier, thereby facilitating the electron transmission of the photocatalyst; and the quality of the reduced graphene is controlled to be homogeneous carbon-doped Bi₃Cl₄The mass percentage of the O semiconductor photocatalyst is 10.0-50.0%, and the homogeneous carbon-doped Bi can be timely achieved₃Cl₄The high-efficiency migration of photo-generated charges on the surface of the O semiconductor photocatalyst does not influence the homogeneous carbon-doped Bi₃Cl₄The absorption efficiency of O semiconductor photocatalysts to light.

The source of the reduced graphene is not particularly limited in the present invention, and commercially available products or self-made products known to those skilled in the art may be used. In a specific embodiment of the present invention, the reduced graphene is preferably prepared by the following steps:

2.5g of KaS₂O₈、2.5g P₂O₅Dissolving 3g of graphite powder in 15mL of concentrated sulfuric acid, heating to 80 ℃, magnetically stirring for 6 hours, and stopping heating; cooling the mixture to room temperature, diluting with 500mL distilled water, filtering with 0.2 μm nylon microporous membrane, and drying in the atmosphere to obtain pre-oxidized graphite；

1g of pre-oxidized graphite was dissolved in 23mL of concentrated sulfuric acid, cooled in an ice-water bath, and then 3g of KMnO was slowly added₄After reacting for 2 hours at 350 ℃, slowly adding 46mL of distilled water into the flask, and stopping the reaction; adding 2.5mL of hydrogen peroxide into the flask, and enabling the solution to become bright yellow; washing to be neutral, then washing for three times by using acetone and concentrated hydrochloric acid respectively, then washing to be neutral, and carrying out vacuum drying to obtain graphene oxide;

and reacting the graphene oxide with a sodium borohydride solution with the concentration of 0.01M to obtain reduced graphene which is marked as RGO.

The photo-Fenton catalyst provided by the invention comprises iron heteropoly acid, and the iron heteropoly acid is loaded on the surface of the reduced graphene in situ to form a complex. In the present invention, the mass of the heteropoly-acid iron is preferably 10.0 to 30.0%, more preferably 15.0% to 25.0%, and even more preferably 25.0% of the mass of the reduced graphene; the mass of the iron element in the heteropoly acid iron is preferably 1-20%, preferably 5-15%, and more preferably 10-15.0% of the mass of the reduced graphene. According to the invention, the quality of the iron heteropoly acid is controlled to be 10.0-30.0% of the quality of the reduced graphene, so that the effect of providing sufficient active sites can be achieved, and the reduced graphene and homogeneous carbon-doped Bi are not influenced₃Cl₄Contact effect of O semiconductor photocatalyst; meanwhile, the quality of the iron element in the heteropoly acid iron is controlled to be 1-20% of the quality of the reduced graphene, and enough active sites can be provided for supplying and homogeneous phase carbon doping Bi₃Cl₄The O semiconductor photocatalyst is excited by light to generate reaction, and when the iron element is excessive, electrons generated by the catalyst cannot enable all active sites to play a role.

Homogeneous carbon-doped Bi in photo-Fenton catalyst₃Cl₄The O semiconductor photocatalyst can generate electrons under the excitation of light, graphene is used as a carrier to load heteropoly acid iron, and homogeneous carbon is doped with Bi₃Cl₄The electrons generated by the photo-excitation of the O semiconductor photocatalyst migrate to the surface of the iron heteropoly acid to remove Fe on the surface of the iron heteropoly acid³⁺Conversion to Fe²⁺For decomposing H₂O₂Produce hydroxyl radical to degradePollutants, and improve pollutant degradation performance.

The invention also provides a preparation method of the photo-Fenton catalyst, which comprises the following steps:

providing homogeneous carbon-doped Bi₃Cl₄O semiconductor photocatalyst and reduced graphene;

The present invention provides homogeneous carbon-doped Bi₃Cl₄O semiconductor photocatalysts and reduced graphene. In the present invention, the homogeneous carbon is doped with Bi₃Cl₄The preparation methods of the O semiconductor photocatalyst and the reduced graphene are consistent with the technical scheme, and are not described again.

According to the invention, under the condition that the pH value is 1-3, the reduced graphene, an iron source, sodium dodecaphosphotungstate and water are mixed for carrying out a composite reaction, so as to obtain a reduced graphene-loaded heteropoly acid iron complex.

In the present invention, the pH is preferably 2; the reagent for adjusting the pH value is not particularly limited in the present invention as long as the pH value of the system can be adjusted to 1 to 3, and specifically, for example, the reagent for adjusting the pH value is preferably hydrochloric acid or nitric acid. According to the invention, the pH value of the system is adjusted to 1-3, so that the reaction of an iron source and sodium dodecyl phosphate tungstate can be promoted to generate the iron heteropoly acid.

In the invention, the preferable dosage ratio of the reduced graphene to the iron source is 0.5-2 mg: 0.005 mol; the mole ratio of the iron source to the sodium dodecaphosphotungstate is preferably 5: 1; the iron source is preferably ferric chloride or ferric nitrate. In the invention, the reduced graphene, the iron source, sodium dodecaphosphotungstate and water are preferably mixed in a manner that the reduced graphene is mixed with water to obtain a reduced graphene aqueous solution, and then the iron source and sodium dodecaphosphotungstate are added to the reduced graphene aqueous solution to obtain a mixed solution. In the invention, the concentration of the reduced graphene aqueous solution is preferably 0.5-2.0 mg/L; the concentration of the iron source in the mixed solution is preferably 0.005 mol/L; the concentration of the sodium dodecaphosphotungstate in the mixed solution is preferably 0.001 mol/L.

In the invention, the temperature of the composite reaction is preferably room temperature, and the time is preferably 16-18 h.

The composite reaction condition of the invention is mild, and the surface of the reduced graphene provides a position for the formation of the iron heteropoly acid crystal, so that the iron heteropoly acid is loaded on the surface of the reduced graphene in situ.

After the reduced graphene loaded iron heteropoly complex is obtained, the invention mixes the reduced graphene loaded iron heteropoly complex and homogeneous phase carbon-doped Bi₃Cl₄And dispersing the O semiconductor photocatalyst in an N, N-dimethylformamide aqueous solution, and carrying out chemical self-assembly to obtain the photo-Fenton catalyst.

In the invention, the reduced graphene-supported heteropoly acid iron complex and homogeneous-phase carbon-doped Bi₃Cl₄The mass ratio of the O semiconductor photocatalyst is preferably 0.1-2: 0.1-5.

In the invention, the concentration of the reduced graphene-loaded iron heteropoly acid complex in an N, N-dimethylformamide aqueous solution is preferably 0.1-2 mg/mL, and more preferably 0.5-1.5 mg/mL; the homogeneous carbon-doped Bi₃Cl₄The concentration of the O semiconductor photocatalyst in the N, N-dimethylformamide aqueous solution is preferably 0.1-5 mg/mL, more preferably 1-4 mg/mL, and even more preferably 2-3 mg/mL. In the present invention, the concentration of N, N-dimethylformamide in the aqueous N, N-dimethylformamide solution is preferably 2 mg/mL.

When reducing graphene-loaded heteropoly acid iron complex and homogeneous phase carbon-doped Bi₃Cl₄The concentration of the O semiconductor photocatalyst in the N, N-dimethylformamide aqueous solution is too low to lead the reduced graphene and heteropoly acid iron complex and homogeneous carbon doped Bi₃Cl₄The O semiconductor photocatalyst is adhered together, and when the concentration is too high, the O semiconductor photocatalyst is difficult to adhere togetherTo remove the influence of the homogeneous carbon doping of Bi₃Cl₄Electrons generated by the O semiconductor photocatalyst under light excitation migrate to the surface of the reduced graphene, so that the catalytic performance is reduced.

In the invention, the temperature of the chemical self-assembly is preferably room temperature, and the time is preferably 6-12 h; the chemical self-assembly is preferably carried out under stirring.

After the chemical self-assembly is completed, the chemical self-assembly reaction liquid is preferably filtered, the solid is washed by deionized water and ethanol, and then the solid is dried. The invention does not specifically limit the washing times of the deionized water and the ethanol; the temperature of the drying is preferably 65 ℃; the drying time is preferably 6-12 h; the drying is preferably carried out in a vacuum drying oven.

In the present invention, the application preferably comprises the steps of:

and mixing the photo-Fenton catalyst, hydrogen peroxide, pollutants to be degraded and water, and performing catalytic degradation under the condition of illumination.

In the present invention, the concentrations of the photo-fenton catalyst and hydrogen peroxide in the reaction solution are preferably 10 mmol/L. In the present invention, the contaminant to be degraded preferably includes rhodamine B, methylene blue, methyl orange or p-nitrophenol.

In the invention, the light source for illumination is preferably simulated sunlight or ultraviolet light; the temperature of the catalytic degradation is preferably room temperature.

In the invention, the homogeneous phase carbon in the photo-Fenton catalyst is doped with Bi₃Cl₄The O semiconductor photocatalyst can generate electrons under the condition of illumination, the electrons can migrate to the surface of the reduced graphene, and Fe in heteropoly acid iron on the surface of the reduced graphene³⁺Conversion to Fe²⁺For decomposing H₂O₂Produce hydroxyl free radical to degrade pollutant and raise pollutant degradationAnd (4) performance.

The photo-fenton catalyst and the preparation method and application thereof provided by the present invention will be described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.

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photo-Fenton catalyst and preparation method and application thereof

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