CN113634250B - Composite photocatalytic material and preparation method and application thereof - Google Patents

Abstract

The invention provides a composite photocatalytic material, a preparation method and application thereof, and relates to the field of water treatment. The composite photocatalytic material includes: carbon foam, metal oxide nano arrays and noble metal nanoparticles. In the present invention, metal oxide nano-arrays are grown in situ on the foamed carbon substrate by impregnation method-hydrothermal method, and then noble metal nanoparticles are loaded on the metal oxide nano-arrays by chemical reduction method to form high specific surface area, moderate pore structure, Three-dimensional porous hierarchical structure composite photocatalytic materials with abundant active sites. Using this material to carry out photocatalytic oxidation treatment of heavily polluted wastewater containing high-priced heavy metals and organic pollutants can remove high-priced heavy metals and organics at the same time. The operation process is simple, the material is cheap, and no other sacrificial agents are added. High, good stability, can be used in drinking water, industrial wastewater, advanced treatment projects of high-priced heavy metals and organic compounds in natural water complex pollution.

Description

A kind of composite photocatalytic material and its preparation method and application

technical field

The invention relates to the technical field of water treatment, in particular to a composite photocatalytic material and its preparation method and application.

Background technique

With the development of industry, more and more pollutants enter the environment, making the types of pollutants in water intricate. The most typical one is the coexistence of organic pollutants and heavy metals. Although different water pollution control technologies have been developed for different pollutants, such as the efficient removal of refractory organic pollutants in water by Fenton or biotechnology, and the removal of heavy metals in water by adsorption or coagulation technologies. However, it is still a difficult problem to realize the removal of organic pollutants and heavy metals simultaneously by a single technical means. In order to meet the new challenges of compound pollution, it is urgent and important to find an efficient water pollution control technology.

Photocatalytic technology has the advantages of low cost, simple operation, mild conditions, high efficiency and environmental friendliness, especially photogenerated electrons and holes can respectively oxidize organic matter and reduce heavy metal ions, providing a new method for the simultaneous removal of complex pollutants, and It also provides new opportunities to improve the overall catalytic efficiency. Compared with the research on improving the activity of heterogeneous photocatalysts through morphology control, doping, surface modification and other methods, the research on improving the utilization efficiency of photogenerated charges by means of homogeneous synergistic reactions has become a recent hot field. Although synergizing the photocatalytic oxidation of organic pollutants and the photocatalytic reduction of high-valent heavy metals can greatly improve the reaction efficiency, for a synergistic photocatalytic system with both heterogeneous and homogeneous reaction processes, the interaction between various pollutant molecules The effects, especially the charge transfer process at the interface of photoexcited catalysts and these pollutants, on the synergistic photocatalytic performance are still poorly understood. On the other hand, although a large number of photocatalytic materials have been developed, the insufficient catalytic efficiency of powder catalysts, difficulty in separation, and limited reactive sites still restrict the application of this technology in practical water treatment.

Contents of the invention

Therefore, the technical problem to be solved by the present invention is to overcome the defects of insufficient catalytic efficiency, difficulty in separation, and limited reactive sites of photocatalytic materials for simultaneous removal of organic pollutants and heavy metals in the prior art, thereby providing a new type of composite photocatalytic Materials and their preparation methods and applications.

In the first aspect, the present invention provides a composite photocatalytic material, comprising: foamed carbon, metal oxide nano-arrays and noble metal nanoparticles, the metal oxide nano-arrays are loaded on the foamed carbon, and the noble metal nanoparticles are loaded on the metal oxide nanoarray.

Further, the metal oxide nano-array includes a metal oxide nano-array formed of at least one of zinc oxide, titanium oxide or tungsten oxide.

Further, the noble metal nanoparticles include at least one of platinum nanoparticles, silver nanoparticles or palladium nanoparticles.

In a second aspect, the present invention provides a method for preparing the composite photocatalytic material, comprising the steps of:

(1) Get foam carbon, cut, clean and dry;

(2) Soak the carbon foam treated in step (1) in the seed crystal solution, take it out, dry it, and calcinate;

(3) placing the material calcined in step (2) in a precursor solution for hydrothermal reaction, cooling to room temperature, cleaning and drying, to obtain a foamed carbon material loaded with metal oxide nano-arrays;

(4) Loading noble metal nanoparticles on the metal oxide nano-array of the material obtained in step (3) by using a chemical reduction method to obtain the composite photocatalytic material.

Further, the seed crystal solution includes at least one of the following solutions: an alcohol solution of a zinc salt, a mixed solution of an alcohol solution of a titanium salt and a hydrochloric acid solution, a mixed solution of an alcohol solution of a tungsten salt and a hydrogen peroxide solution;

The precursor solution includes at least one of the following solutions: a mixed solution of an aqueous solution of zinc salt and a solution of hexamethylenetetramine, an aqueous solution of tungstate, and an aqueous solution of titanium salt.

Further, the molar concentration of the zinc salt in the alcohol solution of the zinc salt is 0.01-0.03 mol/L;

The molar concentration of the titanium salt in the alcohol solution of the titanium salt is 0.01-0.07mol/L, the concentration of the hydrochloric acid solution is 1-6mol/L, and the volume ratio of the alcohol solution of the titanium salt to the hydrochloric acid solution is 10- 15:1;

The molar concentration of the tungsten salt in the alcohol solution of the tungsten salt is 0.01～0.06mol/L, the concentration of the hydrogen peroxide solution is 0.3～1mol/L, the volume of the alcohol solution of the tungsten salt and the hydrogen peroxide solution The ratio is 5-20:1;

In the mixed solution of the aqueous solution of the zinc salt and the hexamethylenetetramine solution, the molar ratio of the zinc salt to the hexamethylenetetramine is 1:1-4;

The molar concentration of tungstate in the aqueous solution of tungstate is 0.01～0.04mol/L;

The molar concentration of the titanium salt in the aqueous solution of the titanium salt is 0.02-0.09mol/L;

More preferably, the zinc salt includes at least one of zinc chloride, zinc sulfate, zinc nitrate, zinc formate, zinc acetate, and zinc benzoate;

The titanium salt includes at least one of titanium tetrachloride, titanium trichloride, titanyl sulfate, and titanium tetrafluoride;

The tungsten salt includes at least one of tungsten hexachloride, tungsten pentachloride, tungsten tetrachloride and tungsten dichloride;

Described tungstate comprises at least one in sodium tungstate, potassium tungstate, ammonium tungstate;

The alcohol includes at least one of methanol, ethanol, ethylene glycol, and isopropanol.

Further, in step (1), the specification of the carbon foam is 45-120 holes per inch;

The cleaning is to ultrasonically clean the carbon foam in nitric acid, acetone, absolute ethanol and deionized water successively, each solvent is cleaned for 15 minutes, the molar concentration of the nitric acid is 1-2mol/L, and the molar concentration of acetone is 0.5- 1.5mol/L, the power of the ultrasonic cleaning is 50-100W.

Further, in step (2), the soaking time is 5 to 10 minutes; the drying temperature is 50 to 150°C; the steps of soaking and drying are repeated 5 to 15 times; the calcination is carried out at 5 to 10°C The temperature is raised to 250-450°C at a rate of 1/min, and the temperature is kept for 30-120 minutes.

Further, in step (3), the condition of the hydrothermal reaction is to react at 100-200°C for 8-15 hours; the hydrothermal reaction is carried out in a reactor, and the volume of the precursor solution in the reactor accounts for 2/3 of the volume of the reactor; the cleaning is to use deionized water to rinse.

Further, in step (4),

Suspend the material obtained in step (3) in the noble metal salt solution, and slowly and evenly add the citrate solution to the noble metal salt solution under the condition of sufficient stirring, gradually raise the temperature to 60-100°C, and stir slowly 30 to 80 minutes, let stand for 1 hour, wait for natural cooling to room temperature, wash and dry with deionized water, and obtain the foamed carbon material loaded with metal oxide nanoarrays;

Alternatively, suspend the material obtained in step (3) in the noble metal salt solution, and slowly and evenly add the borohydride salt solution to the noble metal salt solution under sufficient stirring, stir slowly for 10 minutes, and let it stand for 1 hour , washed with deionized water and dried to obtain the foamed carbon material loaded with metal oxide nanoarrays.

Further, the molar ratio of the noble metal salt to the citrate in the noble metal salt solution and the citrate solution is 1 to 2:1; the molar ratio of the noble metal salt to the borohydride salt in the noble metal salt solution and the borohydride salt solution 2～4:1;

The noble metal salt includes at least one of silver nitrate, palladium nitrate, platinum nitrate, palladium chloride, palladium acetate, platinum dichloride, and chloroplatinic acid; the citrate includes sodium citrate, potassium citrate At least one; the borohydride salt includes at least one of sodium borohydride and potassium borohydride.

Further, the conditions for sufficient stirring are: using a magnetic stirrer to stir, the magnet speed is above 400rpm, or using a mechanical stirrer to stir, the stirring blade speed is above 100rpm;

The conditions for the slow stirring are as follows: stirring with a magnetic stirrer with a magnet speed of 50-100 rpm, or with a mechanical stirrer with a stirrer with a speed of 10-80 rpm.

In a third aspect, the present invention provides the application of the composite photocatalytic material or the composite photocatalytic material obtained by the preparation method in sewage treatment.

Further, the composite photocatalytic material is used to simultaneously remove heavy metals and organic pollutants in sewage, and the method includes:

The pH of the sewage to be treated is adjusted, and the composite photocatalytic material is added to perform light treatment.

Further, the pH value of the sewage to be treated is adjusted to 5-9; a 150-500W xenon lamp is used for light treatment, and the light time is 2-4 hours; the heavy metals include hexavalent chromium, heptavalent manganese or hexavalent uranium at least one of organic pollutants including at least one of phenol, bisphenol A or sulfosalicylic acid.

The technical solution of the present invention has the following advantages:

1. The composite photocatalytic material provided by the present invention includes: carbon foam (Carbon Foam, CF), metal oxide nano-array and noble metal nano-particles, the holes and electrons generated after the material is excited by light are used for photocatalytic oxidation of organic matter respectively and photocatalytic reduction of high-priced heavy metals to achieve simultaneous and efficient removal of the two. Carbon foam as a substrate material not only has moderate pore structure and fast mass transfer, but also has excellent electron transport properties; after in situ growth of metal oxide nanoarrays on it, the formed hierarchical structure can provide a large number of adsorption and catalytic reaction sites, Effectively promote the transfer of photogenerated electrons; and continue to deposit noble metal nanoparticles on the metal oxide nanoarray, which extends the photoresponse range of the photocatalyst from ultraviolet light to visible light, and at the same time significantly improves the photogenerated hole-electron ratio of the photocatalyst. Separation efficiency, improve light energy utilization and photocatalytic efficiency. In addition, the homogeneous photocatalytic process of high-valent heavy metals and organics in water will further enhance the overall catalytic efficiency. In summary, the present invention utilizes the synergistic effect of intramolecular electron transfer and interfacial electron transfer to accelerate the reduction of high-priced heavy metals and the oxidation of organic matter, and provides a novel three-dimensional porous hierarchical structure composite material, which is suitable for both homogeneous and heterogeneous synergistic photoelectric The new catalytic technology has great practical significance and broad application prospects.

2. The present invention grows metal oxide nano-arrays in situ on the foamed carbon substrate by the impregnation method-hydrothermal method, and then deposits noble metal nanoparticles on the nano-arrays by chemical reduction method to form a three-dimensional noble metal-metal oxide-foamed carbon The composite photocatalytic material with porous hierarchical structure has a larger specific surface area and more microfluidic channels, which is helpful for the mass transport of reactants and the full exposure of active sites, so the material has a high specific surface area and a moderate pore structure. , rich active sites, fast mass transfer, high charge separation efficiency, high catalytic activity and other advantages, it has a good application prospect in water treatment.

3. The preparation method of the composite photocatalytic material provided by the present invention has a simple process, can be prepared on a large scale, and the prepared material is easy to recycle and has stable performance.

4. The present invention also provides the application of composite photocatalytic materials in water treatment, which can remove high-priced heavy metals and organic substances in water at the same time. The operation process is simple, the material price is low, no additional sacrificial agents are needed, the treatment cost is low, and the catalytic performance is high. , good stability, can be applied in the advanced treatment project of compound pollution of high-priced heavy metals and organic matter in drinking water, industrial wastewater, natural water, and solved the problem of combined pollution of organic matter and high-priced heavy metals.

Description of drawings

In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the specific implementation or description of the prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

Fig. 1 is the scanning electron micrograph of carbon foam (a), the carbon foam (b) of loading ZnO nanowire array and composite photocatalytic material (c) in the embodiment 2 of the present invention;

Fig. 2 is a graph showing the removal rates of phenol and hexavalent chromium during repeated use of the composite photocatalytic material prepared in Example 2 of the present invention.

Detailed ways

The following examples are provided in order to further understand the present invention better, are not limited to the best implementation mode, and do not limit the content and protection scope of the present invention, anyone under the inspiration of the present invention or use the present invention Any product identical or similar to the present invention obtained by combining features of other prior art falls within the protection scope of the present invention.

If no specific experimental steps or conditions are indicated in the examples, it can be carried out according to the operation or conditions of the conventional experimental steps described in the literature in this field. The raw materials or instruments used are commercially available conventional products, including but not limited to the raw materials or instruments used in the examples of this application.

Example 1

This embodiment provides a method for preparing a composite photocatalytic material, the steps are as follows:

(1) Cut the porous carbon foam (as shown in Figure 1a in the scanning electron microscope image) into a size of 3cm×3cm, and ultrasonically clean it in 2mol/L nitric acid, 1.5mol/L acetone, absolute ethanol and deionized water in sequence. Wash for 15 minutes (power 100W), and dry naturally;

(2) prepare respectively the ethanol solution of tungsten hexachloride, the aqueous solution of sodium tungstate, platinum nitrate solution and sodium citrate solution, wherein, the molar concentration of tungsten salt in the ethanol solution of tungsten hexachloride is 0.02mol/L, will The ethanol solution of tungsten hexachloride and the hydrogen peroxide solution are mixed according to the volume ratio of 10:1 to obtain the mixed solution of the ethanol solution of tungsten hexachloride and the hydrogen peroxide solution; the molar concentration of tungstate in the aqueous solution of sodium tungstate is 0.01mol/L; the molar concentration of platinum nitrate solution is 0.67mol/L, and the molar concentration of sodium borohydride solution is 0.23mol/L;

(3) Soak the cleaned porous carbon foam in the mixed solution of tungsten hexachloride ethanol solution and hydrogen peroxide solution for 5 minutes, take it out and dry it at 50°C, repeat the above process 5 times, and then put it in the muffle furnace Medium calcination, the heating rate is 5°C/min, after the temperature rises to 400°C, it is calcined at this temperature for 100 minutes, and then cooled to room temperature with the furnace;

(4) Place the calcined foamed carbon material in a reaction kettle containing an aqueous solution of sodium tungstate. The aqueous solution of sodium tungstate accounts for 2/3 of the volume of the reaction kettle. It is hydrothermally reacted at a temperature of 180°C for 9 hours. Naturally cooled to room temperature, rinsed with deionized water and dried to obtain foam carbon (WO ₃ /CF) loaded with WO ₃ nanowire arrays;

(5) Suspend the obtained WO ₃ /CF in the platinum nitrate solution, and slowly and evenly add the sodium borohydride solution to the platinum nitrate solution under the condition of magnetic stirring at a rotating speed of 500 rpm (the moles of platinum nitrate and sodium borohydride The ratio is 3:1, continue to react under the condition of 50rpm magnetic stirring for 10 minutes, let it stand for 1 hour, wash with deionized water and dry to obtain a composite photocatalytic material, that is, a composite photocatalytic material loaded with Pt nanoparticles and WO ₃ nanowire arrays. Carbon foam (Pt/WO ₃ /CF).

Example 2

This embodiment provides a method for preparing a composite photocatalytic material, the steps are as follows:

(1) Cut the porous carbon foam (as shown in Figure 1a in the scanning electron microscope) into a size of 3cm×3cm, and ultrasonically clean it in 1mol/L nitric acid, 1mol/L acetone, absolute ethanol, and deionized water in sequence. 15 minutes (power 50W), dry naturally;

(2) prepare ethanol solution of zinc acetate, zinc nitrate aqueous solution, hexamethylenetetramine solution, silver nitrate solution and sodium citrate solution respectively, wherein, the molar concentration of zinc salt in the ethanol solution of zinc acetate is 0.01mol/L The molar concentration of the zinc nitrate aqueous solution is 10mmol/L, and the molar concentration of the hexamethylene tetraammonium solution is 8mmol/L, and the zinc nitrate aqueous solution and the hexamethylene tetraammonium solution are mixed according to a volume ratio of 1:2 to obtain zinc nitrate A mixed solution of aqueous solution and hexamethylene tetraammonium solution; the molar concentration of silver nitrate solution is 2mol/L, and the molar concentration of sodium citrate solution is 1mol/L;

(3) Soak the cleaned porous carbon foam in an ethanol solution of zinc acetate for 5 minutes, take it out and dry it at 80°C, repeat the above process 14 times, and then calcinate it in a muffle furnace with a heating rate of 10°C/min After the temperature rises to 350°C, it is calcined at this temperature for 30 minutes, and then cooled to room temperature with the furnace;

(4) Place the calcined foamed carbon material in a reaction kettle containing a mixed solution of zinc nitrate aqueous solution and hexamethylene tetraammonium solution. The mixed solution accounts for 2/3 of the volume of the reaction kettle, and it is hydrothermally heated at a temperature of 100°C. After reacting for 12 hours, the material was naturally cooled to room temperature, rinsed with deionized water and dried to obtain a carbon foam (ZnO/CF) loaded with ZnO nanowire arrays. The scanning electron microscope image is shown in Figure 1b;

(5) The obtained ZnO/CF is suspended in the silver nitrate solution, and under the condition of magnetic stirring at 450 rpm of the rotating speed, the sodium citrate solution is slowly and evenly added to the silver nitrate solution (the molar ratio of silver nitrate and sodium citrate 2:1), gradually raised the temperature to 80°C, continued to react under the condition of 100rpm magnetic stirring for 80 minutes, let it stand for 1 hour, cooled to room temperature naturally, washed with deionized water and dried to obtain a composite photocatalytic material. That is, carbon foam (Ag/ZnO/CF) loaded with Ag nanoparticles and ZnO nanowire arrays, the scanning electron microscope image is shown in Figure 1c.

Experimental example 1

This experimental example is used to verify the removal effect of the composite photocatalytic material prepared in Example 1 on bisphenol A (PBA) and heptavalent manganese (Mn(VII)) in drinking water. The composite photocatalytic material prepared in Example 1 was used as the experimental object, which was recorded as the Pt/WO ₃ /CF group. As a control, the carbon foam (denoted as WO 3 /CF group) and the carbon foam (referred to as WO ₃ /CF group) obtained by the treatment of the steps (1) to (4) of the embodiment 1 obtained by the treatment of the WO ₃ nanowire array and the treatment obtained by the treatment of the step (1) of the embodiment 1 were also taken respectively. The porous carbon foam (denoted as CF group) was tested. The experimental method is as follows:

Take 3 parts of drinking water samples to be treated containing 20mg/L BPA (recorded as drinking water sample 1), 3 parts of drinking water samples to be treated containing 20mg/L Mn(VII) (recorded as drinking water samples 2), 3 parts of drinking water samples containing 20mg/L Mn(VII) Part of the drinking water sample (recorded as drinking water sample 3) containing 20mg/L BPA and 20mg/L Mn(VII) to be processed, the pH value of the above-mentioned sample is all adjusted to 7.0; Put into embodiment respectively in every kind of drinking water sample 1 The prepared material (Pt/WO ₃ /CF group), the material (WO ₃ /CF group) obtained from the step (1) to (4) of Example 1, the material obtained from the step (1) of Example 1 (CF group), the dosage is 0.5g/L; turn on the 150W xenon lamp light source to simulate sunlight to irradiate the drinking water sample to be treated for 4 hours; use a 0.45 micron filter membrane to filter the drinking water sample after light treatment; use high performance liquid chromatography to detect The remaining BPA concentration in the water was detected by spectrophotometry, and the remaining manganese ion concentration in the water was detected, and the detection results are shown in Table 1.

Table 1 Treatment effect of Pt/WO ₃ /CF group, WO ₃ /CF group and CF group materials on drinking water samples

It can be seen from Table 1 that the composite photocatalytic material prepared by the present invention can efficiently remove bisphenol A and heptavalent manganese in drinking water at the same time, has a synergistic effect, and has a good treatment effect.

Experimental example 2

This experimental example is used to verify the removal effect of the composite photocatalytic material prepared in Example 2 on phenol and hexavalent chromium (Cr(VI)) in industrial wastewater. The composite photocatalytic material prepared in Example 2 is used as the experimental object, which is recorded as Ag/ZnO/CF group. As a comparison, the carbon foam (referred to as ZnO/CF) loaded with ZnO nanowire arrays obtained by the treatment of the steps (1) to (4) of Example 2 and the porous foam obtained by the treatment of the steps (1) of Example 2 were also taken respectively. Carbon (denoted as group CF) was tested. The experimental method is as follows:

Take 3 parts of industrial wastewater samples to be treated containing 20mg/L phenol (denoted as wastewater sample 1), 3 parts of industrial wastewater samples to be treated containing 20mg/L Cr(VI) (denoted as wastewater sample 2), 3 parts of industrial wastewater samples to be treated Process the industrial wastewater sample (recorded as wastewater sample 3) containing 20mg/L phenol and 20mg/L Cr(VI), and the pH value of the above-mentioned sample is all adjusted to 5.0; each kind of drinking water sample is respectively put into embodiment 2 preparation Material (Ag/ZnO/CF group), the material (ZnO/CF group) obtained by the processing of the steps (1) to (4) of Example 2, the material (CF group) obtained by the processing of the step (1) of the embodiment 2, adding The amount is 0.6g/L; turn on the 150W xenon lamp light source to simulate sunlight to irradiate the industrial wastewater sample to be treated for 4 hours; use a 0.45 micron filter membrane to filter the industrial wastewater sample after the light treatment; use high performance liquid chromatography to detect the remaining phenol concentration in the water, The remaining chromium ion concentration in water was detected by inductively coupled plasma-mass spectrometer, and the detection results are shown in Table 2.

Table 2 The treatment effect of Ag/ZnO/CF group, ZnO/CF group and CF group materials on industrial wastewater samples

It can be seen from Table 2 that the composite photocatalytic material prepared by the present invention can efficiently remove phenol and hexavalent chromium in industrial wastewater at the same time, has synergistic effect, fast reaction rate and good treatment effect.

Experimental example 3

This experimental example is used to further verify the stability of the composite photocatalytic material obtained by the preparation method provided by the present invention for simultaneously removing organic matter and heavy metals in water.

Take the industrial wastewater sample containing 20mg/L phenol and 20mg/L Cr(VI) as the treatment object, adjust the pH value of the wastewater sample to 5.0; put the material prepared in Example 2, and the dosage is 0.6g/L; open A 150W xenon lamp light source simulates sunlight to irradiate the industrial wastewater sample to be treated for 4 hours; a 0.45 micron filter membrane is used to filter the industrial wastewater sample after the light treatment. The above operations were processed 5 times, and the remaining phenol concentration and chromium ion concentration in the industrial wastewater after each treatment were detected by high performance liquid chromatography and inductively coupled plasma-mass spectrometer, and the phenol and hexavalent chromium in the industrial wastewater were calculated. The removal rate is shown in Figure 2.

It can be seen from Figure 2 that the novel composite photocatalytic material obtained by the preparation method provided by the present invention has good stability, and still maintains a high removal rate of organic matter and heavy metals after repeated use.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (4)

1. A composite photocatalytic material, characterized in that, comprising: foamed carbon, metal oxide nano-arrays and noble metal nanoparticles, the metal oxide nano-arrays are supported on the foamed carbon, and the noble metal nanoparticles are supported on On the metal oxide nano-array, the metal oxide nano-array is a nano-array formed of tungsten oxide, and the noble metal nanoparticles are platinum nanoparticles, The preparation method of described composite photocatalytic material, comprises the steps: (1) Take foam carbon, cut, wash and dry; (2) Soak the foamed carbon treated in step (1) in the seed crystal solution, take it out, dry it, and calcinate it. Wherein, the seed crystal solution is a mixed solution of ethanol solution of tungsten hexachloride and hydrogen peroxide solution, the molar concentration of tungsten hexachloride in the ethanol solution of tungsten hexachloride is 0.02mol/L, and the The concentration of the hydrogen oxide solution is 0.3~1mol/L, the volume ratio of the ethanol solution of tungsten hexachloride to the hydrogen peroxide solution is 10:1; the soaking time is 5~10 minutes; the drying temperature is 50~150°C ; The steps of soaking and drying are repeated 5 to 15 times; the calcination is heated to 400 °C at a rate of 5 °C/min and kept for 100 minutes; (3) The calcined material in step (2) is placed in the precursor solution for hydrothermal reaction, cooled to room temperature, washed and dried to obtain a foamed carbon material loaded with metal oxide nanoarrays, Wherein, the precursor solution is an aqueous solution of sodium tungstate; the molar concentration of sodium tungstate in the aqueous solution of sodium tungstate is 0.01 mol/L; the condition of the hydrothermal reaction is to react at 180°C for 9 hours; The hydrothermal reaction is carried out in a reactor, and the volume of the precursor solution in the reactor accounts for 2/3 of the volume of the reactor; the cleaning is to use deionized water to rinse; (4) using a chemical reduction method to load noble metal nanoparticles on the metal oxide nanoarray of the material obtained in step (3) to obtain the composite photocatalytic material, Among them, the material obtained in step (3) is suspended in the platinum nitrate solution, and the sodium borohydride solution is slowly and uniformly added to the platinum nitrate solution under the condition of magnetic stirring at a rotating speed of 500 rpm, and the magnetic stirring at a rotating speed of 50 rpm Stir slowly for 10 minutes, stand for 1 hour, wash with deionized water and dry to obtain the composite photocatalytic material; the molar ratio of platinum nitrate and sodium borohydride in the platinum nitrate solution and sodium borohydride solution is 3: 1. 2. The composite photocatalytic material according to claim 1, characterized in that, in step (1), the specification of the carbon foam is 45-120 holes per inch; The cleaning is to ultrasonically clean the carbon foam in nitric acid, acetone, dehydrated ethanol and deionized water successively, each solvent is cleaned for 15 minutes, the molar concentration of the nitric acid is 1~2mol/L, and the molar concentration of acetone is 0.5~ 1.5 mol/L, and the power of the ultrasonic cleaning is 50-100 W. 3. An application of the composite photocatalytic material according to claim 1 or 2 in sewage treatment. 4. The application according to claim 3, wherein the composite photocatalytic material is used to simultaneously remove heavy metals and organic pollutants in sewage, and the method comprises: Adjust the pH of the sewage to be treated, add the composite photocatalytic material and perform light treatment, Wherein, the pH value of the sewage to be treated is adjusted to 5-9; 150-500W xenon lamp is used for light treatment, and the light time is 2-4 hours; the heavy metal is heptavalent manganese, and the organic pollutant is bisphenol A .

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