Preparation and use of supported photo-fenton catalyst

Abstract

Disclosed in the present invention are the preparation and use of a supported photo-Fenton catalyst. The preparation method comprises: I, formulating a sodium tungstate solution and a potassium oxalate solution, adjusting the pH until acidic, and performing a hydrothermal reaction and calcination to obtain a tungsten trioxide composite material; II, formulating a sodium tungstate solution and an ammonium ferrous sulfate solution; III, ultrasonically dispersing the tungsten trioxide composite material in the ammonium ferrous sulfate solution to obtain a suspension; and IV, under continuous stirring, adding the sodium tungstate solution into the suspension in a dropwise manner, stirring same, performing a hydrothermal reaction, and washing and drying same to obtain a tungsten trioxide / iron tungstate nano material. In the present invention, an FeWO4 / WO3 heterojunction is formed by using a hydrothermal synthesis method, which improves the separation efficiency of carriers and the photo-Fenton catalyst activity of the tungsten trioxide / iron tungstate nano material, thereby increasing the catalytic efficiency thereof. The catalyst is suitable for the degradation treatment of photocatalyst wastewater or dye methylene blue and methyl violet, and the preparation process is simple and easy to implement, and has low pollution.

Description

Preparation and application of a supported photo-Fenton catalyst TECHNICAL FIELD

[0001] The present application belongs to the technical field of catalyst materials, and particularly relates to a preparation and application of a supported photo-Fenton catalyst. BACKGROUND

[0002] The traditional Fenton method for treating organic pollutants has the characteristics of fast degradation and non-toxicity and has been widely concerned and applied. However, in the reaction process, iron sludge is inevitably produced, causing secondary pollution. The photo-Fenton method can effectively solve this problem. The photo-Fenton technology combines photocatalysis and Fenton reaction, effectively utilizes solar energy and H2O2, and is one of the most effective technologies for removing organic pollutants. Through the excitation of light, the photocatalyst generates electrons to reduce Fe 3+ to Fe 2+ , which can effectively reduce the production of iron sludge and continuously circulate, achieving efficient catalysis.

[0003] Tungsten trioxide (WO3) has attracted extensive attention of researchers due to its wide light absorption range, low band gap (2.5 eV), better chemical stability, low cost and non-toxicity. However, the low conduction band edge, fast carrier recombination, low electron transport capacity and limited light response range of WO3 hinder its potential catalytic capacity. Coupling two semiconductors to construct a heterojunction to improve the separation efficiency of photo-generated electrons and holes is an effective strategy. The Chinese invention patent with the application number 202010303282.8 discloses a preparation method of a p-type titanium dioxide / n-type tungsten trioxide heterojunction catalyst. The preparation process of the method is complex, and a large amount of organic waste liquid is produced, which is not conducive to environmental protection. Furthermore, the application of the obtained catalyst in photo-Fenton catalysis has not been disclosed. The Chinese invention patent with the application number 201910577165.8 discloses a tungsten trioxide / ferrous oxide composite photocatalyst, a preparation method and application thereof. The preparation process of the method is complex and the conditions are harsh. Furthermore, the application of the obtained catalyst in photo-Fenton catalysis has not been disclosed.

[0004] Therefore, there is a need for a photo-Fenton catalyst with high catalytic efficiency and simple preparation process. SUMMARY

[0005] The technical problem solved by the present application is to provide a preparation method of a supported photo-Fenton catalyst to overcome the shortcomings of the prior art.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a preparation method of a supported photo-Fenton catalyst, characterized in that the method comprises the following steps:

[0007] Step one: sodium tungstate and potassium oxalate are added to deionized water respectively and stirred until completely dissolved to obtain a sodium tungstate solution and a potassium oxalate solution, the sodium tungstate solution and the potassium oxalate solution are mixed, acid is added dropwise to adjust the pH to be acidic, and then the mixture is transferred into a hydrothermal kettle for hydrothermal reaction, the product of the hydrothermal reaction is washed to neutral and dried, and then calcination is performed to obtain a tungsten trioxide composite material with a specific crystal form and morphology;

[0008] Step two: sodium tungstate and ferrous ammonium sulfate are dissolved in deionized water respectively to prepare a sodium tungstate solution and a ferrous ammonium sulfate solution;

[0009] Step three: the tungsten trioxide composite material obtained in step one is ultrasonically dispersed in the ferrous ammonium sulfate solution prepared in step two to obtain a suspension;

[0010] Step four: under continuous stirring, the sodium tungstate solution prepared in step two is added dropwise into the suspension obtained in step three, and then the mixture is transferred into an autoclave for hydrothermal reaction, and after natural cooling to room temperature, centrifugal washing and drying are performed to obtain a tungsten trioxide / iron tungstate nanomaterial;

[0011] Step five: the obtained tungsten trioxide / iron tungstate nanomaterial is annealed under a nitrogen atmosphere to further improve its crystallinity and photocatalytic activity.

[0012] The preparation method of the supported photo-Fenton catalyst is characterized in that the tungsten trioxide / iron tungstate nanomaterial has a core-shell structure, in which tungsten trioxide serves as the core and iron tungstate is uniformly coated on the surface to form a nanoshell with a thickness of 5-20 nm.

[0013] The preparation method of the supported photo-Fenton catalyst has the characteristics that the concentration of the sodium tungstate solution and the potassium oxalate solution in step one is 0.2 mol / L and 0.01 mol / L respectively, and the volume ratio of the mixture is 1:1; the acid is a 2 mol / L hydrochloric acid solution, and the pH is adjusted to 1-2.

[0014] The preparation method of the supported photo-Fenton catalyst has the characteristics that the temperature of the hydrothermal reaction in step one is 180-220 DEG C, and the time is 16-24 hours; the temperature of the calcination is 300-500 DEG C, and the time is 2-4 hours.

[0015] The preparation method of the supported photo-Fenton catalyst has the characteristics that the molar ratio of the sodium tungstate to the ferrous ammonium sulfate in step two is 1:1.

[0016] The preparation method of the supported photo-Fenton catalyst has the characteristics that the molar ratio of the tungsten trioxide composite material to the ferrous ammonium sulfate in the ferrous ammonium sulfate solution in step three is 1:1.5.

[0017] The preparation method of the supported photo-Fenton catalyst has the characteristics that the temperature of the hydrothermal reaction in step four is 180 DEG C, and the time is 12 hours.

[0018] In addition, the application also discloses an application of the supported photo-Fenton catalyst prepared by the method, and the application has the characteristics that the supported photo-Fenton catalyst is applied to photocatalyst wastewater or is applied to degradation treatment of dye methylene blue and methyl violet.

[0019] Compared with the prior art, the application has the following advantages:

[0020] 1. The hydrothermal synthesis method is adopted in the application, the tungsten trioxide composite material is prepared through a hydrothermal reaction first, then the tungsten trioxide composite material is dispersed in a ferrous ammonium sulfate solution to perform a hydrothermal reaction with sodium tungstate, the semiconductor material iron tungstate with a narrow band gap and a wide light utilization range is loaded on the surface of tungsten trioxide particles to form a FeWO4 / WO3 heterojunction, the separation of carriers is promoted, the separation efficiency of the carriers is improved, the iron ions in the iron tungstate form an iron ion cycle through a reaction between the iron ions, hydrogen peroxide and electron holes in a photo-Fenton catalysis process, more free radicals are generated, and therefore, high-efficiency catalysis effect is achieved, the activity of the photo-Fenton catalyst is improved, and therefore, the catalytic efficiency of the tungsten trioxide / iron tungstate nanomaterial as the supported photo-Fenton catalyst is improved.

[0021] 2. The preparation process of the application is simple, the conditions are easy to realize, the calcination temperature is low, and the energy consumption is low.

[0022] 3、 The preparation process of the application produces less waste liquid and pollutes the environment less.

[0023] 4、 The supported photo-Fenton catalyst has excellent catalytic efficiency and is suitable for catalytic degradation of wastewater or application in degradation treatment of dye methylene blue and methyl violet.

[0024] The technical solutions of the application will be further described in detail below with the aid of drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1 is an XRD diagram of existing iron tungstate, tungsten trioxide and tungsten trioxide / iron tungstate nanomaterials prepared in Example 1, Example 5 and Example 6 of the application.

[0026] Fig. 2 is an XPS element spectrum diagram of the tungsten trioxide / iron tungstate nanomaterial prepared in Example 1 of the application.

[0027] Fig. 3 is an XRD diagram of the tungsten trioxide / iron tungstate nanomaterial prepared in Example 1 of the application before and after degradation performance test.

[0028] Fig. 4 is an ultraviolet-visible absorption spectrum diagram of existing iron tungstate, tungsten trioxide and the tungsten trioxide / iron tungstate nanomaterial prepared in Example 1 of the application.

[0029] Fig. 5 is a photocurrent response diagram of existing iron tungstate, tungsten trioxide and the tungsten trioxide / iron tungstate nanomaterial prepared in Example 1 of the application. DETAILED DESCRIPTION

[0030] Example 1

[0031] This example includes the following steps:

[0032] Step one, sodium tungstate and potassium oxalate are respectively added to deionized water and stirred until completely dissolved to obtain a 0.2 mol / L sodium tungstate solution and a 0.01 mol / L potassium oxalate solution, 40 mL of the sodium tungstate solution and 40 mL of the potassium oxalate solution are mixed and stirred for dissolution for 30 min, 2 mol / L hydrochloric acid solution is added dropwise while stirring to adjust the pH to 1.5, and then transferred into a 100 mL hydrothermal kettle, hydrothermal reaction is carried out at 180℃ for 16 h, the product of the hydrothermal reaction is cooled and centrifuged, the obtained precipitate is washed to neutral for three times, constant temperature drying is carried out, and then the tungsten trioxide composite material with specific crystal form and morphology is placed in a crucible and transferred into a muffle furnace for calcination at 300℃ for 3 h, the material has enhanced photocatalytic activity;

[0033] Step two, 1.5 mmol of sodium tungstate and 1.5 mmol of ferrous ammonium sulfate are respectively dissolved in 40 mL of deionized water and stirred for 30 min to prepare a sodium tungstate solution and a ferrous ammonium sulfate solution;

[0034] Step three, 0.5g of tungsten trioxide composite material obtained in step one is added to the ammonium ferrous sulfate solution prepared in step two and ultrasonic dispersed for 10 min to obtain a suspension;

[0035] Step four, under the condition of continuous stirring, the sodium tungstate solution prepared in step two is added dropwise into the suspension obtained in step three and stirred for 30 min, then transferred into a 100mL stainless steel autoclave, hydrothermal reaction at 180℃ for 12h, after natural cooling to room temperature, centrifugal washing and drying, tungsten trioxide / iron tungstate nanomaterial is obtained, recorded as 0.75F / W-1;

[0036] Step five, the obtained tungsten trioxide / iron tungstate nanomaterial is annealed under nitrogen atmosphere to further improve its crystallinity and photocatalytic activity.

[0037] The tungsten trioxide / iron tungstate nanomaterial has a core-shell structure, in which tungsten trioxide is as the core and iron tungstate is uniformly coated on the surface to form a nanoshell layer with a thickness of 5nm.

[0038] Example 2

[0039] This example includes the following steps:

[0040] Step one, sodium tungstate and potassium oxalate are taken and added into deionized water to stir until completely dissolved to obtain 0.2mol / L sodium tungstate solution and 0.01mol / L potassium oxalate solution, 40mL of sodium tungstate solution and 40mL of potassium oxalate solution are mixed and stirred for 30min, 2mol / L hydrochloric acid solution is added dropwise while stirring to adjust PH to 2, then transferred into a 100mL hydrothermal kettle, hydrothermal reaction at 180℃ for 16h, after cooling the hydrothermal reaction product, centrifugal separation is carried out, the obtained precipitate is washed three times to neutral, constant temperature drying is carried out, then placed in a crucible and transferred into a muffle furnace, calcined at 300℃ for 3h to obtain tungsten trioxide composite material with specific crystal form and morphology, which has enhanced photocatalytic activity;

[0041] Step two, 1.5mmol of sodium tungstate and 1.5mmol of ammonium ferrous sulfate are respectively dissolved in 40mL of deionized water and stirred for 30min to prepare sodium tungstate solution and ammonium ferrous sulfate solution;

[0042] Step three, 0.5g of tungsten trioxide composite material obtained in step one is added to the ammonium ferrous sulfate solution prepared in step two and ultrasonic dispersed for 10 min to obtain a suspension;

[0043] Step four, under the condition of continuous stirring, the sodium tungstate solution prepared in step two is added dropwise into the suspension obtained in step three and stirred for 30 min, and then transferred into a 100 mL stainless steel autoclave, hydrothermal reaction at 180°C for 12 h, natural cooling to room temperature, centrifugal washing and drying to obtain tungsten trioxide / iron tungstate nanomaterial, recorded as 0.75F / W-2;

[0044] Step five, the obtained tungsten trioxide / iron tungstate nanomaterial is annealed under nitrogen atmosphere to further improve its crystallinity and photocatalytic activity.

[0045] The tungsten trioxide / iron tungstate nanomaterial has a core-shell structure, in which tungsten trioxide is the core and iron tungstate is uniformly coated on the surface to form a nanoshell with a thickness of 10 nm.

[0046] Example 3

[0047] This example includes the following steps:

[0048] Step one, sodium tungstate and potassium oxalate are taken and added to deionized water to be stirred until completely dissolved to obtain a 0.2 mol / L sodium tungstate solution and a 0.01 mol / L potassium oxalate solution, 40 mL of the sodium tungstate solution and 40 mL of the potassium oxalate solution are mixed and stirred for 30 min, 2 mol / L hydrochloric acid solution is added dropwise while stirring to adjust the pH to 1.0, and then transferred into a 100 mL hydrothermal kettle, hydrothermal reaction at 180°C for 16 h, the product of the hydrothermal reaction is cooled and centrifuged, the obtained precipitate is washed three times to neutral, constant temperature drying is carried out, and then placed in a crucible and transferred into a muffle furnace, calcined at 300°C for 3 h to obtain a tungsten trioxide composite material with a specific crystal form and morphology, which has enhanced photocatalytic activity;

[0049] Step two, 1.5 mmol of sodium tungstate and 1.5 mmol of ferrous ammonium sulfate are respectively dissolved in 40 mL of deionized water and stirred for 30 min to prepare a sodium tungstate solution and a ferrous ammonium sulfate solution;

[0050] Step three, 0.5 g of the tungsten trioxide composite material obtained in step one is added to the ferrous ammonium sulfate solution prepared in step two and ultrasonically dispersed for 10 min to obtain a suspension;

[0051] Step four, under the condition of continuous stirring, the sodium tungstate solution prepared in step two is added dropwise into the suspension obtained in step three and stirred for 30 min, and then transferred into a 100 mL stainless steel autoclave, hydrothermal reaction at 180°C for 12 h, natural cooling to room temperature, centrifugal washing and drying to obtain tungsten trioxide / iron tungstate nanomaterial, recorded as 0.75F / W-2;

[0052] Step five, the obtained tungsten trioxide / iron tungstate nanomaterial is annealed under a nitrogen atmosphere to further improve its crystallinity and photocatalytic activity.

[0053] The tungsten trioxide / iron tungstate nanomaterial has a core-shell structure, wherein tungsten trioxide serves as a core, and iron tungstate is uniformly coated on the surface to form a nanoshell layer with a thickness of 12 nm.

[0054] Example 4

[0055] This example includes the following steps:

[0056] Step one, sodium tungstate and potassium oxalate are respectively added to deionized water and stirred until completely dissolved to obtain a 0.2 mol / L sodium tungstate solution and a 0.01 mol / L potassium oxalate solution. 40 mL of the sodium tungstate solution and 40 mL of the potassium oxalate solution are mixed and stirred for dissolution for 30 min. 2 mol / L hydrochloric acid solution is added dropwise while stirring to adjust the pH to 1.5. Then, it is transferred into a 100 mL hydrothermal kettle and hydrothermally reacted at 220°C for 24 h. After cooling, the hydrothermal reaction product is centrifuged and separated. The obtained precipitate is washed three times to neutral, constant-temperature dried, placed in a crucible, and transferred into a muffle furnace. The tungsten trioxide composite material with a specific crystal form and morphology is calcined at 300°C for 3 h, and the material has enhanced photocatalytic activity.

[0057] Step two, 1.5 mmol of sodium tungstate and 1.5 mmol of ferrous ammonium sulfate are respectively dissolved in 40 mL of deionized water and stirred for 30 min to prepare a sodium tungstate solution and a ferrous ammonium sulfate solution.

[0058] Step three, 0.5 g of the tungsten trioxide composite material obtained in step one is added to the ferrous ammonium sulfate solution prepared in step two and ultrasonically dispersed for 10 min to obtain a suspension.

[0059] Step four, under continuous stirring, the sodium tungstate solution prepared in step two is added dropwise into the suspension obtained in step three and stirred for 30 min. Then, it is transferred into a 100 mL stainless steel autoclave and hydrothermally reacted at 180°C for 12 h. After natural cooling to room temperature, it is centrifuged, washed, and dried to obtain a tungsten trioxide / iron tungstate nanomaterial, which is recorded as 0.75F / W-4.

[0060] Step five, the obtained tungsten trioxide / iron tungstate nanomaterial is annealed under a nitrogen atmosphere to further improve its crystallinity and photocatalytic activity.

[0061] The tungsten trioxide / iron tungstate nanomaterial has a core-shell structure, wherein tungsten trioxide serves as a core, and iron tungstate is uniformly coated on the surface to form a nanoshell layer with a thickness of 15 nm.

[0062] Example 5

[0063] The embodiment comprises the following steps:

[0064] Step one, sodium tungstate and potassium oxalate were added into deionized water respectively and stirred until completely dissolved, obtaining 0.2 mol / L sodium tungstate solution and 0.01 mol / L potassium oxalate solution, 40 mL sodium tungstate solution and 40 mL potassium oxalate solution were mixed and stirred for 30 min, 2 mol / L hydrochloric acid solution was added dropwise while stirring to adjust the pH to 1.5, then transferred into a 100 mL hydrothermal kettle, hydrothermal reaction at 180℃ for 16 h, the hydrothermal reaction product was cooled and centrifuged, the obtained precipitate was washed three times to neutral, constant temperature drying, then placed in a crucible and transferred into a muffle furnace, calcined at 300℃ for 4 h, the tungsten trioxide composite material with specific crystal form and morphology was obtained, and the material has enhanced photocatalytic activity;

[0065] Step two, 1 mmol of sodium tungstate and 1 mmol of ferrous ammonium sulfate were respectively dissolved in 40 mL of deionized water and stirred for 30 min, obtaining sodium tungstate solution and ferrous ammonium sulfate solution;

[0066] Step three, 0.5 g of tungsten trioxide composite material obtained in step one was added to the ferrous ammonium sulfate solution prepared in step two and ultrasonically dispersed for 10 min, obtaining a suspension;

[0067] Step four, under the condition of continuous stirring, the sodium tungstate solution prepared in step two was added dropwise into the suspension obtained in step three and stirred for 30 min, then transferred into a 100 mL stainless steel autoclave, hydrothermal reaction at 180℃ for 12 h, after natural cooling to room temperature, centrifuged, washed and dried, obtaining tungsten trioxide / iron tungstate nanomaterial, recorded as 0.5F / W;

[0068] Step five, the obtained tungsten trioxide / iron tungstate nanomaterial was annealed under nitrogen atmosphere to further improve its crystallinity and photocatalytic activity.

[0069] The tungsten trioxide / iron tungstate nanomaterial has a core-shell structure, in which tungsten trioxide serves as the core and iron tungstate is uniformly coated on the surface, forming a nanoshell layer with a thickness of 18 nm.

[0070] Example 6

[0071] The embodiment comprises the following steps:

[0072] Step one, take sodium tungstate and potassium oxalate respectively into deionized water and stir until completely dissolved, to obtain 0.2mol / L sodium tungstate solution and 0.01mol / L potassium oxalate solution, mix 40mL sodium tungstate solution and 40mL potassium oxalate solution and stir for 30min, drop 2mol / L hydrochloric acid solution while stirring to adjust PH to 1.5, then transfer into 100mL hydrothermal kettle, hydrothermal reaction at 180℃ for 16h, centrifugal separation after cooling the hydrothermal reaction product, the obtained precipitate is washed three times to neutral, constant temperature drying, then placed in a crucible and transferred into a muffle furnace, calcined at 500℃ for 2h, the tungsten trioxide composite material with specific crystal form and morphology, the material has enhanced photocatalytic activity;

[0073] Step two, dissolve 2mmol sodium tungstate and 2mmol ferrous ammonium sulfate in 40mL deionized water respectively and stir for 30min, to prepare sodium tungstate solution and ferrous ammonium sulfate solution;

[0074] Step three, add 0.5g tungsten trioxide composite material obtained in step one into the ferrous ammonium sulfate solution prepared in step two and ultrasonic dispersion for 10min, to obtain a suspension;

[0075] Step four, under the condition of continuous stirring, drop the sodium tungstate solution prepared in step two into the suspension obtained in step three and stir for 30min, then transfer into 100mL stainless steel autoclave, hydrothermal reaction at 180℃ for 12h, natural cooling to room temperature, centrifugal washing and drying, to obtain tungsten trioxide / iron tungstate nanomaterial, recorded as 1.0F / W;

[0076] Step five, annealing treatment of the obtained tungsten trioxide / iron tungstate nanomaterial under nitrogen atmosphere, to further improve its crystallinity and photocatalytic activity.

[0077] The tungsten trioxide / iron tungstate nanomaterial is in core-shell structure, in which tungsten trioxide is as core, and iron tungstate is uniformly coated on the surface, forming a nanoshell layer with thickness of 20nm.

[0078] The degradation performance test of tungsten trioxide / iron tungstate nanomaterial prepared in examples 1-6 under visible light: 100mL methylene blue or methyl violet solution with concentration of 20mg / L is placed in a jacketed reactor, then 50mg photo-Fenton catalyst tungsten trioxide / iron tungstate nanomaterial is added, stirring in a dark box for 30min to make the photocatalyst and dye reach adsorption equilibrium; condensate water is introduced, 300W xenon lamp light source is turned on, continuous stirring, 3mL solution is taken every 15min and the concentration of methylene blue and methyl violet at different time is recorded, finally the degradation efficiency is recorded after 90min, the results are shown in the following table 1.

[0079] Table 1

[0080] From Table 1, it can be seen that the tungsten trioxide / iron tungstate composite photocatalytic materials prepared in Examples 1-6 of the present application have good degradation efficiency on methylene blue and methyl violet, and 0.75F / W-1 has better degradation efficiency, and the degradation efficiency on methylene blue and methyl violet reaches 98% and 99%, respectively.

[0081] Figure 1 is an XRD diagram of existing iron tungstate, tungsten trioxide and the tungsten trioxide / iron tungstate nanomaterials prepared in Example 1, Example 5 and Example 6 of the present application. As can be seen from Figure 1, the tungsten trioxide / iron tungstate nanomaterials prepared in Example 1, Example 5 and Example 6 of the present application all present similar diffraction peaks to tungsten trioxide (WO3). When a high content of iron tungstate is loaded in Example 6, the tungsten trioxide / iron tungstate nanomaterial prepared presents obvious characteristic peaks of iron tungstate (FeWO4), indicating that the iron tungstate is successfully loaded on the tungsten trioxide to prepare a supported photo-Fenton catalyst.

[0082] Figure 2 is an XPS element spectrum diagram of the tungsten trioxide / iron tungstate nanomaterial prepared in Example 1 of the present application. As can be seen from Figure 2, element peaks of Fe2p, O1s, C1s and W4f are observed, indicating that the tungsten trioxide / iron tungstate nanomaterial prepared is composed of iron, tungsten and oxygen elements.

[0083] Figure 3 is an XRD diagram of the tungsten trioxide / iron tungstate nanomaterial prepared in Example 1 of the present application before and after degradation performance test. As can be seen from Figure 3, the XRD characteristic peaks of the tungsten trioxide / iron tungstate nanomaterial before and after degradation performance test do not change obviously, indicating that the tungsten trioxide / iron tungstate nanomaterial prepared has good stability.

[0084] Figure 4 is an ultraviolet-visible absorption spectrum diagram of existing iron tungstate, tungsten trioxide and the tungsten trioxide / iron tungstate nanomaterial prepared in Example 1 of the present application. As can be seen from Figure 4, compared with iron tungstate and tungsten trioxide single components, the tungsten trioxide / iron tungstate nanomaterial prepared in the present application improves the light absorption intensity of tungsten trioxide by introducing iron tungstate, thereby enhancing the activity of the tungsten trioxide / iron tungstate nanomaterial, i.e., photocatalytic performance.

[0085] Figure 5 is a photocurrent response diagram of existing iron tungstate, tungsten trioxide and the tungsten trioxide / iron tungstate nanomaterial prepared in Example 1 of the present application. As can be seen from Figure 5, compared with iron tungstate and tungsten trioxide single components, the tungsten trioxide / iron tungstate nanomaterial prepared in the present application improves the photocurrent response value of tungsten trioxide by introducing iron tungstate, indicating that the heterostructure formed by loading iron tungstate on tungsten trioxide is beneficial to the separation and utilization of carriers, thereby improving the activity of the tungsten trioxide / iron tungstate nanomaterial as a photo-Fenton catalyst.

[0086] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application. Any simple modification, change and equivalent variation of the above embodiments according to the technical essence of the present application are still within the protection scope of the technical scheme of the present application.

Claims

1. A method for preparing a supported photo-Fenton catalyst, characterized in that, The method comprises the following steps: Step one, take sodium tungstate and potassium oxalate respectively into deionized water and stir until completely dissolved to obtain sodium tungstate solution and potassium oxalate solution, mix the sodium tungstate solution and potassium oxalate solution, then add acid dropwise to adjust the pH to be acidic, then transfer into a hydrothermal kettle for hydrothermal reaction, wash the product of the hydrothermal reaction to neutral and dry, and calcine to obtain tungsten trioxide composite material with specific crystal form and morphology; Step two, dissolve sodium tungstate and ferrous ammonium sulfate in deionized water respectively to prepare sodium tungstate solution and ferrous ammonium sulfate solution; Step three, ultrasonically disperse the tungsten trioxide composite material obtained in step one in the ferrous ammonium sulfate solution prepared in step two to obtain a suspension; Step four, under the condition of continuous stirring, drop the sodium tungstate solution prepared in step two into the suspension obtained in step three, then transfer into an autoclave for hydrothermal reaction, naturally cool to room temperature, centrifugal wash and dry to obtain tungsten trioxide / iron tungstate nanomaterial; Step five, anneal the obtained tungsten trioxide / iron tungstate nanomaterial under nitrogen atmosphere to further improve its crystallinity and photocatalytic activity.

2. The preparation method of the supported photo-Fenton catalyst according to claim 1, characterized in that, The tungsten trioxide / iron tungstate nanomaterial is in a core-shell structure, in which tungsten trioxide is as the core and iron tungstate is uniformly coated on the surface to form a nanoshell layer with a thickness of 5-20 nm.

3. The method for preparing a supported photo-Fenton catalyst according to claim 1, characterized in that, The concentration of the sodium tungstate solution and the potassium oxalate solution in step one is 0.2 mol / L and 0.01 mol / L respectively, and the mixing volume ratio is 1:1; the acid is a 2 mol / L hydrochloric acid solution, and the pH is adjusted to 1-2.

4. The method for preparing a supported photo-Fenton catalyst according to claim 1, characterized in that, The temperature of the hydrothermal reaction in step one is 180-220℃, and the time is 16-24h, the calcination temperature is 300-500℃, and the time is 2-4h.

5. The method for preparing a supported photo-Fenton catalyst according to claim 4, characterized in that, The temperature of the hydrothermal reaction in step one is 190-210℃, and the time is 18-22h, the calcination temperature is 350-450℃, and the time is 2.5-3.5h.

6. The method for preparing a supported photo-Fenton catalyst according to claim 1, characterized in that, The molar ratio of sodium tungstate to ferrous ammonium sulfate in step two is 1:

1.

7. The method for preparing a supported photo-Fenton catalyst according to claim 1, characterized in that, The molar ratio of the tungsten trioxide composite material to ferrous ammonium sulfate in the ferrous ammonium sulfate solution in step three is 1:1.

5. 8.The method for preparing a supported photo-Fenton catalyst according to claim 1, characterized in that, The temperature of the hydrothermal reaction in step four is 180℃, and the time is 12h.

9. Use of a supported photo-Fenton catalyst prepared according to the method of any one of claims 1 to 8, characterized in that, The supported photo-Fenton catalyst is applied to the degradation treatment of photocatalyst wastewater or dyes methylene blue and methyl violet.

Images