CN106268891A - A kind of lotus-like porous carbon/oxyhalogen bismuth semiconductors coupling catalysis material, prepare and apply - Google Patents

Abstract

The invention discloses a lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material, preparation and application. The steps are as follows: the air-dried cattail grass is placed in a tube furnace, and carbonized for a period of time under the protection of an inert gas. The collected black powder is the lotus root-shaped porous carbon. A certain mass of lotus root-shaped porous carbon was added to the alcohol solution and bismuth salt and stirred, which was recorded as solution 1; at the same time, the halide was dissolved in the same alcohol solution, which was recorded as solution 2; the stirred solution 2 was quickly added to solution 1, and Continue to stir for a period of time; put the above mixed liquid into a microwave reactor and use different powers for microwave reaction for 1-190 minutes; centrifuge out the reaction precipitate and wash it and dry it to obtain a lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalyst Material. Finally, add a certain concentration of organic pollutants to the photocatalytic material, put it into a photocatalytic instrument for photodegradation reaction, and then measure the performance of the lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material.

Description

A lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material, its preparation and application

technical field

The invention relates to a lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material, its preparation and application, which is an environmental restoration material used for catalytically degrading organic pollutants in a water environment with visible light, and belongs to the field of material preparation and environmental restoration.

Background technique

For a long time, various industrial production needs to use a large amount of chemical raw materials, which in turn produces a large number of high-concentration water pollutants. These sewage often contain a lot of toxic organic substances, and the discharge without treatment or treatment has caused serious pollution to water resources. Because these organic pollutants are difficult to degrade and have strong toxicity and carcinogenicity, they have become a major problem endangering human existence. Therefore, finding a method to remove organic pollutants in water has become a scientific and practical problem to be solved urgently.

Photocatalytic oxidation reaction uses semiconductor materials as photocatalysts, which can oxidize and degrade refractory organic substances into low-toxic or non-toxic aliphatic small molecules or directly mineralize them into inorganic substances such as CO ₂ and H ₂ O. Potential green advanced oxidation technology. Stable, cheap and high-performance semiconductor photocatalytic materials are the core of photocatalytic technology. TiO ₂ has the advantages of strong oxidation ability, high catalytic activity, stability, and non-toxicity. However, TiO ₂ is an intrinsic wide bandgap semiconductor. The problems of low quantum efficiency and low solar energy utilization have always restricted TiO ₂ photocatalysis. Large-scale industrial applications of materials. Therefore, researchers have been actively working on the development of new high-efficiency, visible light (accounting for 43% of the total solar energy) responsive photocatalytic materials.

Bismuth-based semiconductors are an important part of photocatalytic materials, and their most representative compounds are BiOX (X=Cl, Br, I) new layered semiconductor materials. Bismuth-containing compounds are cheap and environmentally friendly, and have recently become a hot spot in the research and development of photocatalysts. Bismuth oxyhalide photocatalysts have good catalytic properties, and they all have obvious absorption in the visible light region. The reason is that the bismuth oxyhalide compound BiOX (X=Cl, Br, I) has a layered crystal structure composed of double ion layers and Bi ₂ O ₂ layers alternately arranged along the c-axis direction, and is an important type of layered semiconductor , this layered crystal structure with open and indirect transitions facilitates the efficient separation and charge transfer of photogenerated electron-hole pairs. Among them, BiOBr and BiOI have a narrow bandgap and can be directly excited by visible light, but their photogenerated electron-hole pairs recombine quickly so that the quantum efficiency is low, and pure BiOX (X=Cl, Br, I) is not stable enough (P.Wang, Angew. Chem. Int. Ed. 2008, 47, 7931-7933; X. Wang, Nature Mater. 2009, 8, 76-80.), limiting their practical applications.

Although BiOX (X=Cl, Br, I) is regarded as a new generation of high-performance environmentally friendly and visible light-responsive photocatalytic materials, it is still constrained by the following three key scientific issues: (1) monomeric BiOX (X=Cl , Br, I) quantum efficiency is low. Although the unique layered structure and indirect bandgap transition mode of BiOX (X=Cl, Br, I) are beneficial to the effective separation and charge transfer of photogenerated electron-hole pairs, the monomeric BiOX (X=Cl, Br, I) In the process of migration, photogenerated electrons and holes still have a large recombination probability, which greatly reduces its photocatalytic efficiency, making it difficult to treat some industrial wastewater containing refractory organic matter or high concentration and large amount of organic matter. Meet the use requirements. (2) Wide bandgap BiOX (X=Cl, Br) has low utilization rate of solar energy. Wide bandgap BiOCl only responds to ultraviolet light, and BiOBr has a limited response range to visible light. Although BiOI has a strong absorption of visible light, the iodine salts that provide I-, such as NaI and KI, are expensive, which is not conducive to the large-scale application of BiOI. Therefore, how to expand the response range of wide bandgap BiOX (X=Cl, Br) to visible light and improve the quantum yield has become one of the key problems to be solved urgently in BiOX (X=Cl, Br, I) materials. (3) Immobilization of BiOX (X=Cl, Br, I) nano photocatalysts: At present, the synthesized BiOX (X=Cl, Br, I) in different microstructure forms are all powder materials. Although the powder catalyst has good dispersibility in the reaction solution, large contact area with the reaction solution, and high catalytic efficiency, it has the problems of easy agglomeration, difficulty in recycling and secondary pollution. Therefore, how to introduce BiOX (X=Cl, Br, I) nanostructure units into suitable supports to achieve catalyst immobilization has become another key issue in the research of BiOX (X=Cl, Br, I) photocatalytic materials.

In view of the limitations of the current development of photocatalytic materials, the research on photocatalytic degradation of organic matter is still in the laboratory stage. Although it has been proved that most organic substances can be successfully degraded, they are still restricted by the three key problems mentioned above (1. Low quantum efficiency; 2. Low utilization rate of solar energy by wide band gap; 3. Immobilization of nano-photocatalysts). Therefore, this technology has not yet been well applied in practice. Therefore, it is crucial for the development and application of photocatalyst materials to prepare a preparation method with the advantages of simplicity, environmental friendliness, controllable microstructure, and suitable for large-scale production, and at the same time, it can effectively solve the above three key scientific problems. important.

Contents of the invention

The purpose of the present invention is to solve the problems such as the large band gap, low quantum efficiency, poor stability, and weak visible light activity of traditional photocatalytic degradation materials, and to provide a porous carbon material based on lotus root-shaped micro-nano hierarchical structure and BiOX (X= Cl, Br, I) composite high-efficiency photocatalytic degradation composite material preparation method and its use method for treating organic pollutants in water bodies.

The technical solution of the present invention is: in order to obtain a new type of cheap, efficient and easy-to-recycle photocatalytic degradation composite material, it is necessary to select a low-cost, easy-to-prepare carrier, and load a photocatalyst on the carrier to achieve the purpose of efficiently degrading organic pollutants in water , to study its use conditions and recycling methods to obtain novel, low-cost, high-efficiency, easy-to-recycle, and reusable composite materials for photocatalytic degradation of organic wastewater. Cattail grass-based porous carbon material not only retains the skeleton structure of cattail herb, but also has interconnected lotus root-like porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material-micro-nano hierarchical pore structure, so it can be used as a carrier for photocatalysts , the dopant body of nano-BiOX (X=Cl, Br, I) is loaded on the carrier, and the high-efficiency photocatalytic degradation composite material is prepared for water environment restoration.

A lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material, which is prepared by microwave radiation method, specifically includes the following steps:

(1) The air-dried cattail grass is placed in a tube furnace, carbonized under the protection of an inert gas, and the black powder collected after cooling is lotus root-shaped porous carbon;

(2) Add the lotus root-shaped porous carbon into the mixed solution of ethanol and ethylene glycol and stir, then add bismuth salt, and record it as solution 1; at the same time, dissolve the halides in the same molar ratio in the mixed solution of ethanol and ethylene glycol, record is solution 2;

(3) Solutions 1 and 2 were stirred rapidly at room temperature; the stirred solution 2 was quickly added to solution 1, and continued to stir at room temperature;

(4) The liquid after above-mentioned mixing is packed into microwave reactor, adopts different powers to carry out microwave reaction;

(5) After the solution is naturally cooled to room temperature, the precipitate is centrifuged and washed with distilled water and absolute ethanol, and then dried in a vacuum oven to obtain a lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material.

Further, the carbonization temperature of the lotus root-shaped porous carbon obtained in step (1) is 550°C-1200°C, and the carbonization time is 0.5-10 hours.

Further, the volume ratio of the mixed solution of ethanol and ethylene glycol in step (2) is 1:0.1-10.

Further, the halide in step (2) is potassium halide or sodium halide. Potassium halide is one of KI, KCl, and KBr; sodium halide is one of NaI, NaCl, and NaBr.

Further, in the step (2), the halide may also be cetyltrimethylammonium bromide or cetyltrimethylammonium chloride of surfactants.

Further, the bismuth salt in step (2) is Bi(NO ₃ ) ₃ ·5H ₂ O or BiCl ₃ .

Further, the reaction power of the microwave reactor in step (4) is 100-1500W, and the reaction time of the microwave reaction is 1-90min.

The lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material of the invention is used for treating refractory organic pollutants in sewage. The specific process is:

(1) Weigh a certain mass of lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material, pour it into a photocatalytic device containing organic wastewater, and light it for a period of time to carry out photocatalytic reaction;

(2) Test the concentration after being degraded by the lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material according to the absorbance or other methods until the content of organic matter in the sewage reaches the standard.

The organic pollutants in the organic sewage are methyl orange, rhodamine B, phenol, polycyclic aromatic hydrocarbons, bisphenol A and the like.

The invention utilizes low-cost cattail grass to prepare a lotus root-shaped porous carbon/bismuth oxyhalide semiconductor composite photocatalytic material to prepare a novel high-performance visible light catalytic degradation composite material for treating organic pollutants in water bodies. Compared with the existing technology, its advantages are:

(1) The present invention is a preparation method of a lotus root-shaped porous carbon/BiOX (X=Cl, Br, I) semiconductor composite photocatalytic material. Simple, low-carbon and environmentally friendly, and can achieve large-scale production;

(2) the present invention provides a kind of preparation method of lotus root shape porous carbon/BiOX (X=Cl, Br, I) semiconductor composite photocatalytic material, this composite material has good stability, strong catalytic ability;

(3) The composite material prepared by the present invention is used for treating refractory organic pollutants in sewage, and the effect is remarkable.

Principle explanation:

Combining BiOX (X=Cl, Br, I) with porous carbon materials can not only improve the stability of photocatalysts, but also use the super adsorption performance of porous carbon materials to reduce the interaction between organic pollutants and BiOX (X=Cl, Br, I) reaction distance, thereby increasing the efficiency of photocatalytic degradation. After the applicant directly carbonized the withered cypress grass, it was found that the cattail grass-based porous carbon material not only retained the characteristic skeleton structure of the cattail herb, but also had an interconnected lotus root-like micro-nano hierarchical pore structure, which greatly increased the ratio of the material. surface area. Composite the porous carbon material with BiOX (X=Cl, Br, I) to form a lotus root-shaped porous carbon/BiOX (X=Cl, Br, I) micro-nano hierarchical composite material, which can be used for photocatalytic degradation of organic pollutants in water . In the process of compounding with BiOX (X=Cl, Br, I), this interconnected pore structure enables BiOX (X=Cl, Br, I) to fully enter the pores and composite with porous carbon, so that the composite material has good "synergy effect". In the process of photocatalysis, the strong adsorption capacity of porous carbon can firmly adsorb organic pollutants on the surface and internal pores, greatly increasing the contact area between BiOX (X=Cl, Br, I) and organic pollutants, and at the same time It can also greatly reduce the reaction distance. Therefore, the combination of this lotus-root-like porous carbon with the highly efficient photocatalytic performance of BiOX (X = Cl, Br, I) has a "synergistic benefit" that enhances its photocatalytic performance.

The high specific surface area and macropores of lotus root-like porous carbon, the effective adsorption of reactant molecules and the effective separation of photogenerated electron-hole pairs are the three factors that improve the performance of composite materials. The combination of C-Bi chemical bonds is formed between the two phases of the composite material. The formation of this chemical bond makes the structure of the lotus root-shaped porous carbon more complete, which greatly improves the photocatalytic performance of the composite material. It is expected to promote the application of cattail grass-based lotus root-shaped porous carbon and its bismuth-based compound composites in environmental protection, photoelectrochemical conversion, and photolysis of water.

Description of drawings

Fig. 1 is (a) SEM image and (b) partially enlarged image of the lotus root-shaped porous carbon/BiOI semiconductor composite photocatalytic material prepared in Example 1.

Figure 2 is the XRD pattern of the lotus root-shaped porous carbon/BiOI semiconductor composite photocatalytic material prepared in Example 1.

Fig. 3 is the (a) ultraviolet-visible diffuse reflectance spectrum and the corresponding (b) band gap value spectrum of the lotus root-shaped porous carbon/BiOI semiconductor composite photocatalytic material prepared in Example 1.

Figure 4 is the photocatalytic spectrum of the lotus root-shaped porous carbon/BiOI semiconductor composite photocatalytic material prepared in Example 1.

Fig. 5 is the degradation rate diagram of the lotus root-shaped porous carbon/BiOI semiconductor composite photocatalytic material prepared in Example 1.

Fig. 6 is the SEM image (a) and partial enlarged image (b) of the lotus root-shaped porous carbon/BiOBr semiconductor composite photocatalytic material prepared in Example 2.

7 is the photocatalytic spectrum of the lotus root-shaped porous carbon/BiOBr semiconductor composite photocatalytic material prepared in Example 2.

Fig. 8 is the degradation rate spectrum of the lotus root-shaped porous carbon/BiOBr semiconductor composite photocatalytic material prepared in Example 2.

Fig. 9 is the SEM image (a) and partial enlarged image (b) of the lotus root-shaped porous carbon/BiOI _0.5 Br _0.5 semiconductor composite photocatalytic material prepared in Example 3.

Figure 10 is the photocatalytic spectrum of the lotus root-shaped porous carbon/BiOI _0.5 Br _0.5 semiconductor composite photocatalytic material prepared in Example 3.

Figure 11 is the degradation rate spectrum of the lotus root-shaped porous carbon/BiOI _0.5 Br _0.5 semiconductor composite photocatalytic material prepared in Example 3.

Figure 12 is the SEM image (a) and partial enlarged image (b) of the lotus root-shaped porous carbon/BiOCl semiconductor composite photocatalytic material prepared in Example 4.

Figure 13 is the photocatalytic spectrum of the lotus root-shaped porous carbon/BiOCl semiconductor composite photocatalytic material prepared in Example 4.

Figure 14 is the degradation rate spectrum of the lotus root-shaped porous carbon/BiOCl semiconductor composite photocatalytic material prepared in Example 4.

Figure 15 is the SEM image (a) and partial enlarged image (b) of the lotus root-shaped porous carbon/BiOI _0.5 Cl _0.5 semiconductor composite photocatalytic material prepared in Example 5.

Figure 16 is the photocatalytic spectrum of the lotus root-shaped porous carbon/BiOI _0.5 Cl _0.5 semiconductor composite photocatalytic material prepared in Example 5.

Figure 17 is the degradation rate spectrum of the lotus root-shaped porous carbon/BiOI _0.5 Cl _0.5 semiconductor composite photocatalytic material prepared in Example 5.

Figure 18 is the SEM image (a) and partial enlarged image (b) of the lotus root-shaped porous carbon/BiOI _0.2 Br _0.8 semiconductor composite photocatalytic material prepared in Example 6.

Figure 19 is the photocatalytic spectrum of the lotus root-shaped porous carbon/BiOI _0.2 Br _0.8 semiconductor composite photocatalytic material prepared in Example 6.

Figure 20 is the degradation rate spectrum of the lotus root-shaped porous carbon/BiOI _0.2 Br _0.8 semiconductor composite photocatalytic material prepared in Example 6.

21 is an SEM image of the lotus root-shaped porous carbon/BiOBr _0.5 Cl _0.5 semiconductor composite photocatalytic material prepared in Example 7.

Figure 22 is the photocatalytic spectrum of the lotus root-shaped porous carbon/BiOBr _0.5 Cl _0.5 semiconductor composite photocatalytic material prepared in Example 7.

Figure 23 is the degradation rate spectrum of the lotus root-shaped porous carbon/BiOBr _0.5 Cl _0.5 semiconductor composite photocatalytic material prepared in Example 7.

detailed description

The use of cattail grass-based porous carbon materials retains the characteristic skeleton structure of cattail grass, and has the characteristics of interconnected lotus root-like micro-nano hierarchical pore structure. The 3D porous carbon material with interconnected pore structure was prepared by a simple process using cattail grass as raw material. This interconnected pore structure allows BiOX (X=Cl, Br, I) to fully enter the pores and recombine with porous carbon, so that the Composite materials exert their "synergistic benefits" to prepare reusable and efficient new visible light catalytic degradation composite materials. It is used to degrade organic pollutants and achieve the purpose of controlling water pollution.

Example 1

1. Material preparation:

(1) The air-dried cattail grass is placed in a tube furnace and carbonized for a period of time under the protection of an inert gas. The black powder collected after cooling is lotus root-shaped porous carbon.

(2) Add 36mg of lotus root-shaped porous carbon to 20ml of ethanol and ethylene glycol mixed solution and stir in a beaker for 30 minutes (8ml of ethanol, 12ml of ethylene glycol), then add 3mmol (1.4553g) of Bi(NO _{3 ) 3.5H 2 O} , recorded as solution 1; at the same time, 3mmol of KI (0.4980g) was dissolved in 20ml of ethanol and ethylene glycol mixed solution (8ml of ethanol, 12ml of ethylene glycol), recorded as solution 2;

(3) Solutions 1 and 2 were stirred rapidly at room temperature for 30 minutes; the stirred solution 2 was quickly added to solution 1, and stirred rapidly at room temperature for 60 minutes;

(4) The liquid after above-mentioned mixing is loaded into microwave reactor and carries out microwave reaction 50 minutes with 500W;

(5) The solution after the microwave reaction is naturally cooled to room temperature, the precipitate is centrifuged and washed twice with distilled water and absolute ethanol, and then dried in a drying oven at 60°C to obtain the lotus root-shaped porous carbon/bismuth oxyiodide semiconductor Composite photocatalytic materials.

2. Material application:

(1) Weigh 10 mg of lotus root-shaped porous carbon/BiOI semiconductor composite photocatalytic material and pour it into a photocatalytic bottle;

(2) Measure 50ml of rhodamine B solution of 10mg/L that has been prepared, and pour it into the above-mentioned photocatalytic bottle;

(3) Put the mixed solution into the photocatalytic instrument, stir rapidly, and absorb in dark for 60 minutes to make it reach the adsorption equilibrium;

(4) Use a syringe to draw 4ml of the solution, label it and store it away from light;

(5) Turn on the 500W xenon lamp, and start timing, and repeat the process in (4) every 10 minutes until sampling for 120 minutes;

(6) Centrifuge the sample taken out, use a disposable pipette to take the upper layer and drop it into a cuvette, and measure the absorbance with a UV-Vis spectrophotometer;

(7) The degradation rate of the organic pollutant rhodamine B by the prepared lotus root-shaped porous carbon/BiOI semiconductor composite photocatalytic material was calculated according to the absorbance.

Fig. 1 is the SEM image of the sample prepared in Example 1. It can be seen from the figure that BiOI grows on the surface of the lotus root-shaped porous carbon in the form of sheets.

Figure 2 is the XRD spectrum of the sample prepared in Example 1. There are diffraction peaks at 29.65°, 45.38°, and 55.15° at 2θ angles, respectively corresponding to (102), (200), (212) and other main crystal planes, and BiOI standard spectrum The figure (JCPDS No.10-0445) is consistent, in which the diffraction peak intensity corresponding to the 2θ angle of 29.65° is the largest; while the diffraction peaks corresponding to the 2θ angles of 31.59°, 66.23°, and 75.23° are the diffraction peaks of C. This indicates that the lotus root-like porous carbon/BiOI semiconductor composite photocatalytic material was indeed synthesized.

Figure 3(a) is the ultraviolet-visible diffuse reflectance spectrum of the composite material. It can be seen from the figure that the composite material has strong absorption in the visible light region of 400-600nm. According to the formula (ahv) ^1/2 ＝A(hv－E _g ) from the UVDRS spectrum, use (ahv) ^1/2 to plot hv to obtain the graph (b). It can be seen from the figure (b) that the bandgap of the composite material is significantly lower than that of pure BiOI (the forbidden band width of pure BiOI is 1.72-1.93). This shows that the prepared composite material has improved the absorption and utilization of visible light, which provides the possibility to improve the catalytic activity of visible light.

It can be seen from Fig. 4 and Fig. 5 that the lotus root-shaped porous carbon/BiOI semiconductor composite photocatalytic material prepared by the reaction has good photocatalytic performance. Under the irradiation of 500W xenon lamp, the degradation rate of the composite material to RhB can reach more than 85% within 120 minutes.

Example 2

Material preparation: (1) Air-dried cattail grass was placed in a tube furnace and carbonized for a period of time under the protection of an inert gas. The black powder collected after cooling was lotus root-shaped porous carbon.

(2) Add 36mg of lotus root-shaped porous carbon to 20ml of ethanol and ethylene glycol mixed solution and stir in a beaker for 30 minutes (8ml of ethanol, 12ml of ethylene glycol), then add 3mmol (1.4553g) of Bi(NO _{3 ) 3.5H 2 O} , recorded as solution 1; at the same time, 3mmol of KBr (0.3570g) was dissolved in 20ml of ethanol and ethylene glycol mixed solution (8ml of ethanol, 12ml of ethylene glycol), recorded as solution 2;

(3) Solutions 1 and 2 were stirred rapidly at room temperature for 30 minutes; the stirred solution 2 was quickly added to solution 1, and stirred rapidly at room temperature for 60 minutes;

(4) The liquid after above-mentioned mixing is loaded into microwave reactor and carries out microwave reaction 40 minutes with 600W;

(5) After the microwave reaction, the solution was naturally cooled to room temperature, the precipitate was centrifuged and washed twice with distilled water and absolute ethanol, and then dried in a drying oven at 60°C to obtain the lotus root-shaped porous carbon/BiOBr semiconductor composite light catalytic material

Material application:

(1) Weigh 10 mg of lotus root-shaped porous carbon/BiOBr semiconductor composite photocatalyst material and pour it into a photocatalytic bottle;

(2) Measure 50ml of rhodamine B solution of 10mg/L that has been prepared, and pour it into the above-mentioned photocatalytic bottle;

(3) Put the mixed solution into the photocatalytic instrument, stir rapidly, and absorb in dark for 60 minutes to make it reach the adsorption equilibrium;

(4) Use a syringe to draw 4ml of the solution, label it and store it away from light;

(5) Turn on the 500W xenon lamp, and start timing, and repeat the process in (4) every 10 minutes until sampling for 120 minutes;

(6) Centrifuge the sample taken out, use a disposable pipette to take the upper layer and drop it into a cuvette, and measure the absorbance with a UV-Vis spectrophotometer;

(7) The degradation rate of the organic pollutant rhodamine B by the prepared lotus root-shaped porous carbon/BiOBr semiconductor composite photocatalytic material was calculated according to the absorbance.

Example 3

(1) The air-dried cattail grass is placed in a tube furnace and carbonized for a period of time under the protection of an inert gas. The black powder collected after cooling is lotus root-shaped porous carbon.

(2) Add 36mg of lotus root-shaped porous carbon to 20ml of ethanol and ethylene glycol mixed solution and stir in a beaker for 30 minutes (8ml of ethanol, 12ml of ethylene glycol), then add 3mmol (1.4553g) of Bi(NO _{3 ) 3.5H 2 O} , recorded as solution 1; at the same time, 1.5mmol of KI (0.2490g) and 1.5mmol of KBr (0.1785g) were dissolved in 20ml of ethanol and ethylene glycol mixed solution (8ml of ethanol, Ethylene glycol 12ml), denoted as solution 2;

(3) Solutions 1 and 2 were stirred rapidly at room temperature for 30 minutes; the stirred solution 2 was quickly added to solution 1, and stirred rapidly at room temperature for 60 minutes;

(4) The liquid after above-mentioned mixing is loaded into microwave reactor and carries out microwave reaction 35 minutes with 700W;

(5) After the microwave reaction, the solution was naturally cooled to room temperature, and the precipitate was centrifuged and washed twice with distilled water and absolute ethanol, and then dried in a drying oven at 60°C to obtain the lotus root-shaped porous carbon/BiOI _0.5 Br _0.5 Semiconductor Composite Photocatalytic Materials

Material application:

(1) Weigh 10 mg of lotus root-shaped porous carbon/BiOI _0.5 Br _0.5 semiconductor composite photocatalytic material and pour it into a photocatalytic bottle;

(2) Measure 50ml of rhodamine B solution of 10mg/L that has been prepared, and pour it into the above-mentioned photocatalytic bottle;

(3) Put the mixed solution into the photocatalytic instrument, stir rapidly, and absorb in dark for 60 minutes to make it reach the adsorption equilibrium;

(4) Use a syringe to draw 4ml of the solution, label it and store it away from light;

(5) Turn on the 500W xenon lamp, and start timing, and repeat the process in (4) every 10 minutes until sampling for 120 minutes;

(6) Centrifuge the sample taken out, use a disposable pipette to take the upper layer and drop it into a cuvette, and measure the absorbance with a UV-Vis spectrophotometer;

(7) The degradation rate of the organic pollutant rhodamine B by the prepared lotus root-shaped porous carbon/BiOI _0.5 Br _0.5 semiconductor composite photocatalytic material was calculated according to the absorbance.

Example 4

(1) The air-dried cattail grass is placed in a tube furnace and carbonized for a period of time under the protection of an inert gas. The black powder collected after cooling is lotus root-shaped porous carbon.

(2) Add 36mg of lotus root-shaped porous carbon to 20ml of ethanol and ethylene glycol mixed solution and stir for 30 minutes (8ml of ethanol, 12ml of ethylene glycol), then add 3mmol (1.4553g) of Bi(NO ₃ ) ₃ 5H ₂ O, recorded as solution 1; at the same time, 3 mmol of KCl (0.225 g) was dissolved in 20 ml of ethanol and ethylene glycol mixed solution (8 ml of ethanol, 12 ml of ethylene glycol), which was recorded as solution 2;

(3) Solutions 1 and 2 were stirred rapidly at room temperature for 30 minutes; the stirred solution 2 was quickly added to solution 1, and stirred rapidly at room temperature for 60 minutes;

(4) The liquid after above-mentioned mixing is loaded into microwave reactor and carries out microwave reaction 50 minutes with 500W;

(5) After the microwave reaction, the solution was naturally cooled to room temperature, the precipitate was centrifuged and washed twice with distilled water and absolute ethanol, and then dried in a drying oven at 60°C to obtain the lotus root-shaped porous carbon/BiOCl semiconductor composite light catalytic material

Material application:

(1) Weigh 10 mg of lotus root-shaped porous carbon/BiOCl semiconductor composite photocatalytic material and pour it into a photocatalytic bottle;

(2) Measure 50ml of rhodamine B solution of 10mg/L that has been prepared, and pour it into the above-mentioned photocatalytic bottle;

(3) Put the mixed solution into the photocatalytic instrument, stir rapidly, and absorb in dark for 60 minutes to make it reach the adsorption equilibrium;

(4) Use a syringe to draw 4ml of the solution, label it and store it away from light;

(5) Turn on the 500W xenon lamp, and start timing, and repeat the process in (4) every 10 minutes until sampling for 120 minutes;

(6) Centrifuge the sample taken out, use a disposable pipette to take the upper layer and drop it into a cuvette, and measure the absorbance with a UV-Vis spectrophotometer;

(7) The degradation rate of the organic pollutant rhodamine B by the prepared lotus root-shaped porous carbon/BiOCl semiconductor composite photocatalytic material was calculated according to the absorbance.

Example 5

(1) The air-dried cattail grass is placed in a tube furnace and carbonized for a period of time under the protection of an inert gas. The black powder collected after cooling is lotus root-shaped porous carbon.

(2) Add 36mg of lotus root-shaped porous carbon to 20ml of ethanol and ethylene glycol mixed solution and stir for 30 minutes (8ml of ethanol, 12ml of ethylene glycol), then add 3mmol (1.4553g) of Bi(NO ₃ ) ₃ 5H ₂ O, recorded as solution 1; at the same time, 1.5mmol of trimethylhexadecyl ammonium chloride and 1.5mmol of KI were dissolved in 20ml of ethanol and ethylene glycol mixed solution (wherein ethanol 4ml, ethanol Glycol 16ml), is recorded as solution 2;

(3) Solutions 1 and 2 were stirred rapidly at room temperature for 30 minutes; the stirred solution 2 was quickly added to solution 1, and stirred rapidly at room temperature for 60 minutes;

(4) The liquid after above-mentioned mixing is loaded into microwave reactor and carries out microwave reaction 40 minutes with 600W;

(5) After the microwave reaction, the solution was naturally cooled to room temperature, and the precipitate was centrifuged and washed twice with distilled water and absolute ethanol, and then dried in a drying oven at 60°C to obtain the lotus root-shaped porous carbon/BiOI _0.5 Cl _0.5 Semiconductor Composite Photocatalytic Materials

Material application:

(1) Weigh 10 mg of lotus root-shaped porous carbon/BiOI _0.5 Cl _0.5 semiconductor composite photocatalytic material and pour it into a photocatalytic bottle;

(2) Measure 50ml of rhodamine B solution of 10mg/L that has been prepared, and pour it into the above-mentioned photocatalytic bottle;

(3) Put the mixed solution into the photocatalytic instrument, stir rapidly, and absorb in dark for 60 minutes to make it reach the adsorption equilibrium;

(4) Use a syringe to draw 4ml of the solution, label it and store it away from light;

(5) Turn on the 500W xenon lamp, and start timing, and repeat the process in (4) every 10 minutes until sampling for 120 minutes;

(6) Centrifuge the sample taken out, use a disposable pipette to take the upper layer and drop it into a cuvette, and measure the absorbance with a UV-Vis spectrophotometer;

(7) The degradation rate of the organic pollutant rhodamine B by the prepared lotus root-shaped porous carbon/BiOI _0.5 Cl _0.5 semiconductor composite photocatalytic material was calculated according to the absorbance.

Example 6

(1) The air-dried cattail grass is placed in a tube furnace and carbonized for a period of time under the protection of an inert gas. The black powder collected after cooling is lotus root-shaped porous carbon.

(2) Add 36mg of lotus root-shaped porous carbon to 20ml of ethanol and ethylene glycol mixed solution and stir for 30 minutes (8ml of ethanol, 12ml of ethylene glycol), then add 3mmol (1.4553g) of Bi(NO ₃ ) ₃ 5H ₂ O, recorded as solution 1; at the same time, 0.6mmol of KI (0.225g) and 2.4mmol of cetyltrimethylammonium bromide were dissolved in 20ml of ethanol and ethylene glycol mixed solution (wherein ethanol 2ml, ethylene glycol 18ml), recorded as solution 2;

(3) Solutions 1 and 2 were stirred rapidly at room temperature for 30 minutes; the stirred solution 2 was quickly added to solution 1, and stirred rapidly at room temperature for 60 minutes;

(4) The liquid after above-mentioned mixing is loaded into microwave reactor and carries out microwave reaction 35 minutes with 700W;

(5) After the microwave reaction, the solution was naturally cooled to room temperature, the precipitate was centrifuged and washed twice with distilled water and absolute ethanol, and then dried in a drying oven at 60°C to obtain the lotus root-like porous carbon/BiOI0.2Br0. 8 Semiconductor composite photocatalytic materials

Material application:

(1) Weigh 10 mg of lotus root-shaped porous carbon/BiOI _0.2 Br _0.8 semiconductor composite photocatalytic material and pour it into a photocatalytic bottle;

(2) Measure 50ml of rhodamine B solution of 10mg/L that has been prepared, and pour it into the above-mentioned photocatalytic bottle;

(3) Put the mixed solution into the photocatalytic instrument, stir rapidly, and absorb in dark for 60 minutes to make it reach the adsorption equilibrium;

(4) Use a syringe to draw 4ml of the solution, label it and store it away from light;

(5) Turn on the 500W xenon lamp, and start timing, and repeat the process in (4) every 10 minutes until sampling for 120 minutes;

(6) Centrifuge the sample taken out, use a disposable pipette to take the upper layer and drop it into a cuvette, and measure the absorbance with a UV-Vis spectrophotometer;

(7) The degradation rate of the organic pollutant rhodamine B by the prepared lotus root-shaped porous carbon/BiOI _0.2 Br _0.8 semiconductor composite photocatalytic material was calculated according to the absorbance.

Example 7

(1) The air-dried cattail grass is placed in a tube furnace and carbonized for a period of time under the protection of an inert gas. The black powder collected after cooling is lotus root-shaped porous carbon.

(2) Add 36mg of lotus root-shaped porous carbon to 20ml of ethanol and ethylene glycol mixed solution and stir for 30 minutes (8ml of ethanol, 12ml of ethylene glycol), then add 3mmol (1.4553g) of Bi(NO ₃ ) ₃ 5H ₂ O, recorded as solution 1; at the same time, 1mmol of KCl (0.7456g), 0.5mmol of trimethylhexadecyl ammonium chloride, 1mmol of NaBr (0.1029g) and 0.5mmol of Trimethylhexadecylammonium bromide is dissolved in 20ml ethanol and ethylene glycol mixed solution (wherein ethanol 5ml, ethylene glycol 15ml), is recorded as solution 2;

(3) Solutions 1 and 2 were stirred rapidly at room temperature for 30 minutes; the stirred solution 2 was quickly added to solution 1, and stirred rapidly at room temperature for 60 minutes;

(4) The liquid after above-mentioned mixing is loaded into microwave reactor and carries out microwave reaction 25 minutes with 1000W;

(5) After the microwave reaction, the solution was naturally cooled to room temperature, and the precipitate was centrifuged and washed twice with distilled water and absolute ethanol, and then dried in a drying oven at 60°C to obtain the lotus root-shaped porous carbon/BiOBr _0.5 Cl _0.5 Semiconductor Composite Photocatalytic Materials

Material application:

(1) Weigh 10 mg of lotus root-shaped porous carbon/BiOBr _0.5 Cl _0.5 semiconductor composite photocatalytic material and pour it into a photocatalytic bottle;

(2) Measure 50ml of rhodamine B solution of 10mg/L that has been prepared, and pour it into the above-mentioned photocatalytic bottle;

(3) Put the mixed solution into the photocatalytic instrument, stir rapidly, and absorb in dark for 60 minutes to make it reach the adsorption equilibrium;

(4) Use a syringe to draw 4ml of the solution, label it and store it away from light;

(5) Turn on the 500W xenon lamp, and start timing, and repeat the process in (4) every 10 minutes until sampling for 120 minutes;

(6) Centrifuge the sample taken out, use a disposable pipette to take the upper layer and drop it into a cuvette, and measure the absorbance with a UV-Vis spectrophotometer;

(7) The degradation rate of the organic pollutant rhodamine B by the prepared lotus root-shaped porous carbon/BiOBr0.5Cl0.5 semiconductor composite photocatalytic material was calculated according to the absorbance.

Claims (10)

1. lotus-like porous carbon/oxyhalogen bismuth semiconductors coupling catalysis material, it is characterised in that use microwave irradiation to enter Row preparation specifically includes following steps:

(1) cattail after air-drying is placed in tube furnace, carbonization under inert gas shielding, and the black powder collected after cooling is i.e. For lotus-like porous carbon；

(2) lotus-like porous carbon is added in ethanol and ethylene glycol mixed solution stirring, is subsequently adding bismuth salt, is designated as solution 1； The halogenide of identical mol ratio is dissolved in ethanol and ethylene glycol mixed solution simultaneously, is designated as solution 2；

(3) quickly stir under solution 1 and 2 room temperature；Solution 2 after stirring is rapidly joined in solution 1, and at room temperature continues to stir Mix；

(4) above-mentioned mixed liquid is loaded microwave reactor, use different capacity to carry out microwave reaction；

(5) treat that solution naturally cools to room temperature, use distilled water and absolute ethanol washing after being centrifuged out precipitate, then do in vacuum Dry in dry case, obtain lotus-like porous carbon/oxyhalogen bismuth semiconductors coupling catalysis material.

Lotus-like porous carbon the most according to claim 1/oxyhalogen bismuth semiconductors coupling catalysis material, it is characterised in that The lotus-like porous carbon carburizing temperature obtained in step (1) is 550 DEG C-1200 DEG C, and carbonization time is 0.5-10 hour.

Lotus-like porous carbon the most according to claim 1/oxyhalogen bismuth semiconductors coupling catalysis material, it is characterised in that In step (2), the volume ratio of ethanol and ethylene glycol mixed solution is 1:0.1～10.

Lotus-like porous carbon the most according to claim 1/oxyhalogen bismuth semiconductors coupling catalysis material, it is characterised in that In step (2), halogenide is potassium halide or sodium halide.

Lotus-like porous carbon the most according to claim 4/oxyhalogen bismuth semiconductors coupling catalysis material, it is characterised in that Potassium halide is KI, the one in KCl, KBr；Sodium halide is NaI, the one in NaCl, NaBr.

Lotus-like porous carbon the most according to claim 1/oxyhalogen bismuth semiconductors coupling catalysis material, it is characterised in that In step (2), halogenide is to may also be surfactant-based cetyl trimethylammonium bromide or cetyl trimethyl chlorination Ammonium.

Lotus-like porous carbon the most according to claim 1/oxyhalogen bismuth semiconductors coupling catalysis material, it is characterised in that In step (2), bismuth salt is Bi (NO₃)₃·5H₂O or BiCl₃。

Lotus-like porous carbon the most according to claim 1/oxyhalogen bismuth semiconductors coupling catalysis material, it is characterised in that In step (4), the reaction power of microwave reactor is 100～1500W, and the response time of microwave reaction is 1～90min.

9. the method that microwave irradiation prepares lotus-like porous carbon/oxyhalogen bismuth semiconductors coupling catalysis material, its feature It is, comprises the following steps:

(1) cattail after air-drying is placed in tube furnace, and carbonization under inert gas shielding, carburizing temperature is 550 DEG C-1200 DEG C, carbonization time is 0.5-10 hour, and the black powder collected after cooling is lotus-like porous carbon；

(2) lotus-like porous carbon is added in ethanol and ethylene glycol mixed solution stirring, is subsequently adding bismuth salt, is designated as solution 1； The halogenide of identical mol ratio is dissolved in ethanol and ethylene glycol mixed solution simultaneously, is designated as solution 2；Described ethanol and ethylene glycol mix The volume ratio closing solution is 1:0.1～10；Described halogenide is potassium halide or sodium halide or surfactant cetyl front three Base ammonium bromide or hexadecyltrimethylammonium chloride；Bismuth salt is Bi (NO₃)₃·5H₂O or BiCl₃；

(3) quickly stir under solution 1 and 2 room temperature；Solution 2 after stirring is rapidly joined in solution 1, and at room temperature continues to stir Mix；

(4) above-mentioned mixed liquid is loaded microwave reactor, use different capacity to carry out microwave reaction, microwave reactor Reaction power is 100～1500W, and the response time of microwave reaction is 1～90min；

(5) treat that solution naturally cools to room temperature, use distilled water and absolute ethanol washing after being centrifuged out precipitate, then do in vacuum Dry in dry case, obtain lotus-like porous carbon/oxyhalogen bismuth semiconductors coupling catalysis material.

10. the lotus-like porous carbon described in claim 1/oxyhalogen bismuth semiconductors coupling catalysis material is used for processing in sewage difficulty Degradable organic pollutant.