Bismuth oxybromide-based photocatalytic material, preparation method and application

Abstract

The invention provides a bismuth oxybromide-based photocatalytic material, and a preparation method and application thereof, and the preparation method comprises the following steps: (1) dissolving bismuth nitrate pentahydrate and polyvinylpyrrolidone in an alcoholic solution, rapidly stirring to obtain a mixed solution, adding potassium bromide into the mixed solution, and continuing to fully stir for reaction; and (2) transferring the mixed solution into a reaction kettle with a polytetrafluoroethylene lining, carrying out solvothermal reaction, carrying out centrifugal suction filtration separation on the obtained product, washing and drying to obtain the photocatalytic material. The bismuth oxybromide-based photocatalytic material, the preparation method and the application have the advantages that the bismuth oxybromide-based photocatalytic material is excellent in performance and high in visible light response capability, dyes can be quickly degraded in a short time, and the treatment efficiency of printing and dyeing wastewater can be obviously improved.

Description

Technical Field

[0001] The invention relates to the field of inorganic nano photocatalysts, and in particular to a bismuth oxybromide-based photocatalytic material, a preparation method and an application thereof. Background Art

[0002] my country ranks first in the world in dye production. A large amount of printing and dyeing wastewater is generated during the production and use of dyes. It has the characteristics of high chromaticity and high chemical oxygen demand, and is currently one of the most difficult organic wastewaters to treat. Printing and dyeing wastewater has a high content of toxic and harmful chemical components, stable chemical properties, complex structure, and some are difficult to be degraded by microorganisms. It has three-cause effects and seriously threatens the safety of the water ecological environment. It is urgent to develop efficient and low-cost treatment methods. At present, the commonly used treatment methods for printing and dyeing wastewater include adsorption, electrochemical oxidation, advanced oxidation, etc.

[0003] Among them, photocatalysis technology in advanced oxidation process is considered to be one of the cleanest and most effective treatment methods, and has been proven to be an effective method for degrading printing and dyeing wastewater. Photocatalysis technology uses photocatalysts made of semiconductor materials to excite valence band electrons after being irradiated by light, thereby generating ·OH, ·O 2- Active substances such as TiO2 undergo photocatalytic redox reactions, mineralizing organic pollutants in printing and dyeing wastewater into H2O, CO2 and other small molecules. It has the advantages of cleanliness, high efficiency, low secondary pollution and reusability. However, traditional photocatalysts such as TiO2 have a wide band gap and almost no visible light response ability, which limits their application in actual production.

[0004] In order to make full use of the abundant solar energy, BiOBr with good activity is selected as the photocatalyst material. BiOBr-based semiconductor materials have a narrow bandgap and a unique layered structure, which improves the visible light response ability and the effective separation of photogenerated carriers. However, a single BiOBr material can only absorb high-energy sunlight, and the charge migration and separation efficiency are limited, so the photocatalytic activity needs to be further improved. Morphology regulation can regulate the valence band structure, create new active sites, and promote the separation of electron-hole pairs. The preparation method is simple and it is not easy to introduce other impurities. Therefore, morphology regulation is expected to greatly improve the catalytic activity of BiOBr-based photocatalyst materials and provide a new solution for the efficient and clean removal of printing and dyeing wastewater. Summary of the invention

[0005] The purpose of the present invention is to provide a bismuth oxybromide-based photocatalytic material, a preparation method and an application thereof. The photocatalyst material has excellent performance and strong visible light response capability, can achieve rapid degradation of dyes in a short time, and significantly improves the treatment efficiency of printing and dyeing wastewater.

[0006] To achieve the above object, the present invention provides a method for preparing a bismuth oxybromide-based photocatalytic material, comprising the following steps:

[0007] (1) dissolving bismuth nitrate pentahydrate and polyvinyl pyrrolidone in an alcohol solution, rapidly stirring to obtain a mixed solution, adding potassium bromide to the mixed solution, and continuing to stir sufficiently for reaction;

[0008] (2) The mixed solution is transferred to a polytetrafluoroethylene-lined reactor for a solvothermal reaction, and the obtained product is separated by centrifugal filtration, washed and dried to obtain a photocatalytic material.

[0009] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate, polyvinyl pyrrolidone and potassium bromide is 0.5-1.5 mmol: 0.2-1.0 g: 0.5-1.5 mmol.

[0010] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate to potassium bromide is 0.6-1.4 mmol:0.6-1.4 mmol.

[0011] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate to potassium bromide is 0.7-1.3 mmol:0.7-1.3 mmol.

[0012] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate to potassium bromide is 0.8-1.2 mmol:0.8-1.2 mmol.

[0013] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate to potassium bromide is 0.9-1.1 mmol:0.9-1.1 mmol.

[0014] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate to potassium bromide is 1.0 mmol:1.0 mmol.

[0015] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate to polyvinyl pyrrolidone is 0.7-1.3 mmol: 0.3-0.9 g.

[0016] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate to polyvinyl pyrrolidone is 0.8-1.2 mmol: 0.4-0.8 g.

[0017] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate to polyvinyl pyrrolidone is 0.9-1.1 mmol: 0.5-0.7 g.

[0018] Preferably, in step (1), the ratio of bismuth nitrate pentahydrate to polyvinyl pyrrolidone is 1.0 mmol:0.6 g.

[0019] Preferably, in step (1), the types of alcohol solution include methanol, ethylene glycol, glycerol and mannitol.

[0020] Preferably, in step (1), stirring is performed at room temperature for 30 to 120 minutes;

[0021] In step (2), the drying temperature is 40 to 80° C. and the drying time is 1 to 5 hours.

[0022] Preferably, in step (2), the solvent thermal reaction temperature is 120 to 180° C., and the heating time is 1 to 3 hours.

[0023] Preferably, in step (2), the solvent thermal reaction temperature is 130 to 170° C., and the heating time is 1.5 to 2.5 hours.

[0024] Preferably, in step (2), the solvent thermal reaction temperature is 140 to 160° C., and the heating time is 1.7 to 2.3 hours.

[0025] Preferably, in step (2), the solvent thermal reaction temperature is 150° C. and the heating time is 2 hours.

[0026] A bismuth oxybromide-based photocatalytic material is prepared by a method for preparing a bismuth oxybromide-based photocatalytic material.

[0027] The invention discloses an application of bismuth oxybromide-based photocatalytic material for degrading methyl orange and rhodamine B in water.

[0028] Preferably, the specific steps are as follows: dispersing the photocatalytic material in an aqueous solution containing a dye, stirring in a dark environment until adsorption-desorption equilibrium is reached, performing photocatalytic degradation under visible light, sampling at intervals, filtering the taken samples through a membrane, and measuring the concentration of the filtrate.

[0029] Therefore, the present invention adopts the above-mentioned bismuth oxybromide-based photocatalytic material, preparation method and application, and the technical effects are as follows:

[0030] (1) The BiOBr-based photocatalyst material prepared by the present invention has excellent performance and strong visible light response ability, and can achieve rapid degradation of dyes in a short time, significantly improving the treatment efficiency of printing and dyeing wastewater.

[0031] (2) The BiOBr-based photocatalyst material prepared by the present invention has a simple preparation method, does not require complicated metal ion doping, has low raw material cost, is easy to operate, and has strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a comparison chart of the photocatalytic activity of the photocatalytic materials of Examples 1 to 4 of the present invention to methyl orange;

[0033] Figure 2 This is a comparison chart of the photocatalytic activity of the photocatalytic materials of Examples 1 to 4 of the present invention to Rhodamine B;

[0034] Figure 3 The XRD diagrams of the photocatalytic materials of Examples 1 to 4 of the present invention;

[0035] Figure 4 The SEM images of the photocatalytic materials of Examples 1 to 4 of the present invention;

[0036] Figure 5 The ultraviolet-visible diffuse reflectance spectra of the photocatalytic materials of Examples 1 to 4 of the present invention;

[0037] Figure 6 The photocurrent diagrams of Examples 1 and 4 of the present invention;

[0038] Figure 7 The degradation efficiency of methyl orange is compared between this patent and comparative documents 1 and 3. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0040] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0041] Experimental reagents

[0042] All reagents were of analytical grade and used without further purification. Deionized water was used throughout the study.

[0043] Bismuth nitrate pentahydrate (Bi(NO3)3·5H2O, 99.0%) was selected from Aladdin;

[0044] Potassium bromide (KBr, 99.0%) was purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai test);

[0045] Methanol (CH4O) and ethylene glycol (C2H6O) were purchased from Beijing Tongguang Fine Chemical Co., Ltd.

[0046] Glycerol (C3H8O) was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0047] Mannitol (C6H 14 O6) Choose Beijing Solebow Technology Co., Ltd.;

[0048] Polyvinylpyrrolidone (PVP(K30)), methyl orange and rhodamine B were supplied by Maclean (Shanghai, China).

[0049] Experimental equipment

[0050] Xenon lamp: Made in China Yuyu

[0051] UV-Vis Spectrophotometer: T6 New Century - Beijing Puxi General Instrument Co., Ltd.

[0052] XRD: Rigaku Ultima IV

[0053] XPS: Thermo Scientific ESCALAB 250Xi

[0054] SEM: ZEISS GeminiSEM 300

[0055] UV-Vis Diffuse Reflectance Spectroscopy: Shimadzu UV-3600i Plus

[0056] Steady-state transient fluorescence spectroscopy: Edinburgh FLS1000

[0057] Electrochemical workstation: CHI760E.

[0058] Example 1

[0059] The present invention provides a method for preparing a bismuth oxybromide-based photocatalytic material, comprising the following steps:

[0060] Weigh 0.4851g (1mmol) of bismuth nitrate pentahydrate and 0.2g of polyvinyl pyrrolidone into a beaker, add 60ml of methanol solution, stir at room temperature for 30min, add 0.119g (1mmol) of potassium bromide to the uniformly stirred mixture, stir at room temperature for 60min, transfer the uniformly stirred mixture into a polytetrafluoroethylene-lined reactor, and heat at 160°C for 3h. The resulting suspension is centrifuged at 8000r / min for 10min, and after solid-liquid separation, the sample is washed 3 times with ethanol and deionized water in a suction filtration device, and the obtained material is dried in an oven at 60°C for use.

[0061] The present invention provides an application of a bismuth oxybromide-based photocatalytic material, and the application for the degradation of methyl orange comprises the following steps:

[0062] The prepared BiOBr-based photocatalyst material was subjected to a methyl orange degradation experiment. A xenon lamp (300W) was used as a light source to simulate sunlight. 50 mg of the photocatalytic material was dispersed in 50 ml of a 20 mg / L methyl orange solution and stirred for 30 min in the dark to achieve adsorption-desorption equilibrium. Then, the solution was reacted for 120 min under a λ>420 nm filter and illumination conditions. During the whole process, samples were taken every 10 min and the methyl orange concentration in the liquid was determined by a UV-visible spectrophotometer after passing through a 0.45 μm filter membrane.

[0063] The present invention provides an application of a bismuth oxybromide-based photocatalytic material, and the application for the degradation of rhodamine B comprises the following steps:

[0064] The prepared BiOBr-based photocatalyst material was subjected to a rhodamine B degradation experiment. The difference from the methyl orange degradation experiment is that the pollutant was replaced with rhodamine B of the same concentration, and the degradation time was adjusted to almost complete degradation.

[0065] Example 2

[0066] A method for preparing a BiOBr-based photocatalyst material is different from that of Example 1 in that the solvent methanol is replaced by an equal volume of ethylene glycol solution.

[0067] An application of a BiOBr-based photocatalyst material is different from Example 1 in that the BiOBr-based photocatalyst material prepared using ethylene glycol as a solvent is used to degrade methyl orange.

[0068] An application of a BiOBr-based photocatalyst material is different from Example 1 in that the BiOBr-based photocatalyst material prepared using ethylene glycol as a solvent is used to degrade Rhodamine B.

[0069] Example 3

[0070] A method for preparing a BiOBr-based photocatalyst material is different from that of Example 1 in that the solvent methanol is replaced by an equal volume of propylene glycol solution.

[0071] An application of a BiOBr-based photocatalyst material is different from Example 1 in that the BiOBr-based photocatalyst material prepared using glycerol as a solvent is used to degrade methyl orange.

[0072] An application of a BiOBr-based photocatalyst material is different from Example 1 in that the BiOBr-based photocatalyst material prepared using glycerol as a solvent is used to degrade Rhodamine B.

[0073] Example 4

[0074] A method for preparing a BiOBr-based photocatalyst material is different from that of Example 1 in that the solvent methanol is replaced by an equal volume of mannitol solution.

[0075] An application of a BiOBr-based photocatalyst material is different from Example 1 in that the BiOBr-based photocatalyst material prepared using mannitol as a solvent is used to degrade methyl orange.

[0076] An application of a BiOBr-based photocatalyst material is different from Example 1 in that the BiOBr-based photocatalyst material prepared using mannitol as a solvent is used to degrade Rhodamine B.

[0077] The properties of the BiOBr-based photocatalyst materials prepared using Examples 1 to 4 are as follows:

[0078] like Figure 1 As shown, the comparison of the photocatalytic adsorption (0-30 min) and photocatalytic degradation of methyl orange in Examples 1 to 4 proves that Example 3 has the best adsorption and catalytic effects, followed by Example 2. Under the simulated visible light of a 300W xenon lamp, the degradation rate of methyl orange in Example 3 can reach more than 95% in 1.5 hours.

[0079] like Figure 2 As shown, the comparison of the photocatalytic adsorption (0-30 min) and photocatalytic degradation of Rhodamine B in Examples 1 to 4 proves that Example 2 has the best adsorption and catalytic effects, followed by Example 1 and Example 4. Under the simulated visible light of a 300W xenon lamp, the degradation rate of Rhodamine B in Example 2 can reach more than 99%, and the degradation rates of Rhodamine B in Examples 1 and 4 can reach more than 98% in 20 minutes.

[0080] like Figure 3 As shown, samples of Examples 1 to 4 correspond to the standard cards, proving the successful synthesis of BiOBr-based photocatalytic materials, and Example 2 has the highest crystallinity.

[0081] like Figure 4 As shown, the samples of Examples 1 to 3 formed a regular honeycomb spherical structure, and the stacking of the sample of Example 4 was more obvious.

[0082] like Figure 5 As shown, the light absorption capacity of the sample in Example 2 is better than that in Example 4 and Example 3, and the light absorption performance is consistent with the photocatalytic degradation law of the dye Rhodamine B.

[0083] like Figure 6 As shown, the photogenerated electron-hole separation ability of the sample in Example 1 is better than that of Example 2 and Example 4.

[0084] Comparative Example

[0085] like Figure 7 As shown, the BiOBr-based photocatalytic material was prepared by the preparation method of the present invention and the formula of comparative document 1 (CN104226339A). The research results showed that after 30 minutes of dark reaction to reach adsorption-desorption equilibrium, the degradation efficiency of 20 mg / L methyl orange in the present invention reached 90.33% in 120 minutes, while that in comparative document 1 was 67.23%.

[0086] The BiOBr-based photocatalytic material was prepared strictly according to the preparation method of Reference Document 3. Under the above experimental conditions, the degradation efficiency of Reference Document 3 (CN113209993A) for 20 mg / L methyl orange was 51.11% in 120 minutes.

[0087] Therefore, the present invention adopts the above-mentioned bismuth oxybromide-based photocatalytic material, preparation method and application, which has excellent performance and strong visible light response ability, can achieve rapid degradation of dyes in a short time, and significantly improve the treatment efficiency of printing and dyeing wastewater.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a bismuth oxybromide-based photocatalytic material, characterized in that: The following steps are involved: (1) dissolving bismuth nitrate pentahydrate and polyvinyl pyrrolidone in an alcohol solution, rapidly stirring to obtain a mixed solution, adding potassium bromide to the mixed solution, and continuing to stir sufficiently for reaction; (2) The mixed solution is transferred to a polytetrafluoroethylene-lined reactor for a solvothermal reaction, and the obtained product is separated by centrifugal filtration, washed and dried to obtain a photocatalytic material.

2. The method for preparing a bismuth oxybromide-based photocatalytic material according to claim 1, characterized in that: In step (1), the ratio of bismuth nitrate pentahydrate, polyvinyl pyrrolidone and potassium bromide is 0.5-1.5 mmol: 0.2-1.0 g: 0.5-1.5 mmol.

3. The method for preparing a bismuth oxybromide-based photocatalytic material according to claim 1, characterized in that: In step (1), the ratio of bismuth nitrate pentahydrate to potassium bromide is 0.6-1.4 mmol:0.6-1.4 mmol.

4. The method for preparing a bismuth oxybromide-based photocatalytic material according to claim 1, characterized in that: In step (1), the ratio of bismuth nitrate pentahydrate to polyvinyl pyrrolidone is 0.7-1.3 mmol: 0.3-0.9 g.

5. The method for preparing a bismuth oxybromide-based photocatalytic material according to claim 1, characterized in that: In step (1), the types of alcohol solution include methanol, ethylene glycol, glycerol and mannitol.

6. The method for preparing a bismuth oxybromide-based photocatalytic material according to claim 1, characterized in that: In step (1), stirring is performed at room temperature for 30 to 120 minutes; In step (2), the drying temperature is 40 to 80° C. and the drying time is 1 to 5 hours.

7. The method for preparing a bismuth oxybromide-based photocatalytic material according to claim 1, characterized in that: In step (2), the solvent thermal reaction temperature is 120 to 180° C., and the heating time is 1 to 3 hours.

8. A bismuth oxybromide-based photocatalytic material, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 7.

9. An application of a bismuth oxybromide-based photocatalytic material, characterized in that: Used to degrade methyl orange and rhodamine B in water bodies.

10. The use of a bismuth oxybromide-based photocatalytic material according to claim 9, characterized in that: Specifically, the photocatalytic material is dispersed in an aqueous solution containing a dye, stirred in a dark environment until adsorption and desorption equilibrium is reached, photocatalytic degradation is carried out under visible light, sampling is performed at intervals, and the concentration of the filtrate is measured after the sample is filtered through a membrane.

Images