A BC-BiOBr-O V Preparation method of nanocomposite material

Abstract

The present invention discloses a BC-BiOBr-O V The invention discloses a preparation method of a nanocomposite material. The preparation method uses sawdust as raw material, H2SO4 solution as solvent, and adopts a calcination method to prepare BC; uses Bi(NO3)3·5H2O, BC and KBr as raw materials, and ethylene glycol as solvent, and then adopts a solvothermal method to combine biochar carbonized from sawdust with BiOBr rich in oxygen vacancies, thereby constructing BC-BiOBr-O with stable structure, large specific surface area, strong visible light response ability, high carrier separation efficiency and abundant catalytic active sites. V Nanocomposite materials, the obtained BC‑BiOBr‑O V Nanocomposites have the advantages of stable structure, large specific surface area, strong visible light response ability, high carrier separation efficiency and abundant catalytic active sites. They are expected to be used in the photocatalytic activation of persulfate (hereinafter referred to as PS) to degrade organic pollutants.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental pollution control, and in particular to a BC-BiOBr-O V Method for preparing nanocomposite materials. Background Art

[0002] BiOBr has a structure of interlaced [B2O2] sheets and double Bi sheets, containing interlaced anions and anionic groups, which can induce an internal electrostatic field and promote the separation of photogenerated carriers. It is well known that oxygen vacancies with abundant localized electrons can significantly promote the adsorption and activation of molecular oxygen. Therefore, the catalytic activity of BiOBr can be optimized by constructing surface oxygen vacancies. Currently, various methods have been successfully used to prepare BiOBr nanomaterials, and there are numerous reports on the degradation of various pollutants using BiOBr materials. However, reports on the performance of BiOBr composite catalysts rich in oxygen vacancies in the photocatalytic activation of PDS for the degradation of organic pollutants are rare.

[0003] BC has an ideal pore structure and specific surface area, rich surface functional groups and mineral elements, and these characteristics give it good catalytic potential. Combining BC with different nano-metal oxides / hydroxides can, on the one hand, give full play to the advantages of BC's large specific surface area, so that it can better disperse metal / metal oxide nanoparticles, make the composite magnetic, and facilitate recovery; on the other hand, BC can provide catalytic active sites, such as oxygen-containing functional groups, nitrogen groups, and defect edges, to enhance catalytic activity. In addition, BC can also effectively inhibit the overflow of metal ions and improve the stability of the catalyst. Therefore, combining BC with BiOBr rich in oxygen vacancies to further enhance the carrier separation efficiency and catalytic activity is an effective strategy to improve catalytic efficiency. The preparation of BC-BiOBr-O by solvothermal method is a promising method for the synthesis of BC-BiOBr-O by solvothermal method. V Little is known about the performance of nanocomposites for photocatalytic activation of PDS for degradation of organic pollutants. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems existing in the prior art and provide a BC-BiOBr-O V Method for preparing nanocomposite materials.

[0005] To achieve the above object, the present invention provides a technical solution: a BC-BiOBr-O V The invention relates to a preparation method of a nanocomposite material, wherein the preparation method combines biochar carbonized from sawdust with BiOBr rich in oxygen vacancies by a solvothermal method, thereby constructing BC-BiOBr-O nanocomposite material with stable structure, large specific surface area, strong visible light response ability, high carrier separation efficiency and abundant catalytic active sites. VThe nanocomposite material, the preparation method specifically comprises the following steps:

[0006] Step (1): After sieving sawdust at a certain mesh size, the sawdust is immersed in an appropriate amount of 60-90 wt.% H2SO4 solution at a certain solid-liquid ratio, and stirred at room temperature for 10-240 minutes to obtain a solid-liquid mixture;

[0007] Step (2): adding an appropriate amount of deionized water to the solid-liquid mixture obtained in step (1) to dilute the solution to 5-50 wt.%, then transferring it to an oven, keeping it at a certain temperature for 20-240 minutes, letting it cool naturally, filtering and washing it until it is neutral, and then drying it at a certain temperature for 6-24 hours to obtain sawdust;

[0008] Step (3): grinding the sawdust obtained in step (2), sieving it under certain mesh conditions, and finally transferring it to a tube furnace, heating it to a holding temperature under a nitrogen atmosphere, and keeping it at the holding temperature for 30-360 minutes to obtain BC;

[0009] Step (4): dissolving a certain amount of Bi(NO3)3·5H2O in a certain amount of ethylene glycol solution and stirring continuously for 10-120 min to obtain a mixed solution;

[0010] Step (5): dissolve a certain amount of KBr and the BC in step (3) in a certain amount of ethylene glycol solution and ultrasonicate for 10-120 min;

[0011] Step (6): Add the solution obtained in step (5) dropwise to the mixed solution obtained in step (4), continue stirring for 30-360 min, and then quickly fill with N2 for a certain period of time;

[0012] Step (7): The solution obtained in step (6) is transferred to a hydrothermal reactor, heated to a certain insulation temperature, and kept at the insulation temperature for 12-48 hours. After naturally cooling to room temperature, the sample is centrifuged and washed, and finally vacuum dried at a certain temperature for 6-24 hours to obtain BC-BiOBr-O V Nanocomposite materials.

[0013] Preferably, in step (1), the sawdust screening requirement is 30-90 mesh, and the solid-liquid ratio of sawdust to H2SO4 solution is 1-30%.

[0014] Preferably, the insulation temperature in step (2) is 80-300°C, and the drying temperature is 50-250°C.

[0015] Preferably, in step (3), the sawdust screening requirement is 60-150 mesh, and the insulation temperature is 400-800°C.

[0016] Preferably, the mass of Bi(NO3)3·5H2O used in step (4) is 1-20 g, and the volume of ethylene glycol is 30-600 mL.

[0017] Preferably, the mass of BC used in step (5) is 0-10 g, the mass of KBr is 0.1-10 g, and the volume of ethylene glycol is 10-400 mL.

[0018] Preferably, the time for filling with N2 in step (6) is 1-30 minutes.

[0019] Preferably, the insulation temperature in step (7) is 120-400°C, and the vacuum drying temperature is 40-90°C.

[0020] Beneficial effects of the present invention:

[0021] The present invention combines biochar carbonized from sawdust with BiOBr rich in oxygen vacancies by a solvent thermal method to construct BC-BiOBr-O V The nanocomposite material significantly improves the adsorption and activation ability of BiOBr matrix material for molecular oxygen, and successfully improves its band structure and the separation and migration ability of photogenerated electrons and holes. The preparation process is simple and the production cost is low. The obtained BC-BiOBr-O V Nanocomposites have the advantages of stable structure, large specific surface area, strong visible light response ability, high carrier separation efficiency and rich catalytic active sites, and are expected to be used in photocatalytic activation of persulfate to degrade organic pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 This is the XRD pattern of the samples prepared in Examples 1 to 4 of the present invention;

[0024] Figure 2 It is 4BC-BiOBr-O obtained in Examples 1 to 4 of the present invention. V TEM images of the nanocomposites at different magnifications;

[0025] Figure 3 This is a graph showing the rate of degradation of tetracycline (hereinafter referred to as TC) by activating PDS using samples obtained in Examples of the present invention;

[0026] Figure 4 Graph showing the rate of degradation of Rhodamine B (hereinafter referred to as RhB) by activating PDS with samples obtained in Examples of the present invention. DETAILED DESCRIPTION

[0027] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0028] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0029] Reference Figures 1-4 , a preferred embodiment of the present invention, a BC-BiOBr-O V A method for preparing a nanocomposite material, wherein the method adopts a solvent thermal method to prepare BiOBr-biochar (hereinafter referred to as BC-BiOBr-O) rich in oxygen vacancies V ) nanocomposite materials, BC was prepared by calcination with sawdust as raw materials and H2SO4 solution as solvent; biochar carbonized from sawdust was combined with BiOBr rich in oxygen vacancies by solvothermal method with Bi(NO3)3·5H2O, BC and KBr as raw materials and ethylene glycol as solvent, thus constructing BC-BiOBr-O V Nanocomposite materials.

[0030] The obtained BC-BiOBr-O V Nanocomposites have the advantages of stable structure, large specific surface area, strong visible light response ability, high carrier separation efficiency and abundant catalytic active sites. They are expected to be used in the photocatalytic activation of persulfate (hereinafter referred to as PS) to degrade organic pollutants.

[0031] Example 1

[0032] A BC-BiOBr-O V Method for preparing nanocomposite materials.

[0033] (1) 6 g of sawdust sieved through 50 mesh was soaked in an 80 wt% H2SO4 solution with a solid-to-liquid ratio of 15%. After stirring at room temperature for 2 h, an appropriate amount of deionized water was added to dilute the H2SO4 solution to 20 wt%. The mixture was then placed in an oven and kept at 140°C for 2 h. After cooling naturally, the resulting product was filtered and washed until neutral, and then dried at 120°C for 8 h. The dried sawdust was ground and sieved through 120 mesh, then transferred to a tube furnace under a nitrogen atmosphere and kept at 550°C for 2 h to obtain BC.

[0034] (2) Dissolve 7.76g of Bi(NO3)3·5H2O in 200mL of ethylene glycol and stir continuously for 60min to obtain solution A1; dissolve 0g of BC and 1.90g of KBr in 80mL of ethylene glycol and sonicate for 60min to obtain solution B1. Add solution B1 dropwise to solution A1 and stir continuously for 2h. Then, quickly fill with N2 and maintain for 10min. Then transfer the obtained solution to a hydrothermal reactor and keep it at 220℃ for 22h. After cooling naturally, the obtained product is washed with deionized water and ethanol, centrifuged, and finally dried in a vacuum environment at 80℃ for 6h to obtain 0BC-BiOBr-O with a total mass fraction of BC of 0%. V Nanocomposite materials (hereinafter referred to as BiOBr-O V ).

[0035] Example 2

[0036] A BC-BiOBr-O V Method for preparing nanocomposite materials.

[0037] (1) 8 g of sawdust sieved through 60 mesh was soaked in a 75 wt% H2SO4 solution with a solid-to-liquid ratio of 10%. After stirring at room temperature for 1 hour, an appropriate amount of deionized water was added to dilute the H2SO4 solution to 15 wt%. The sawdust was then placed in an oven and kept at 120°C for 1 hour. After cooling naturally, the resulting product was filtered and washed until neutral, and then dried at 105°C for 10 hours. The dried sawdust was ground and sieved through 100 mesh, then transferred to a tube furnace under a nitrogen atmosphere and kept at 600°C for 1 hour to obtain BC.

[0038] (2) 3.88 g Bi(NO3)3·5H2O was dissolved in 100 mL ethylene glycol and stirred continuously for 30 min to obtain solution A2; 0.19 g BC and 0.95 g KBr were dissolved in 40 mL ethylene glycol and ultrasonicated for 30 min to obtain solution B2. Solution B2 was added dropwise to solution A2 and stirred continuously for 1 h. N2 was then rapidly introduced and maintained for 5 min. The resulting solution was then transferred to a hydrothermal reactor and kept warm at 200°C for 24 h. After natural cooling, the resulting product was washed with deionized water and ethanol and centrifuged. Finally, it was dried in a vacuum environment at 60°C for 8 h to obtain 4BC-BiOBr-O with a total mass fraction of BC of 4%. V Nanocomposite materials.

[0039] Example 3

[0040] A BC-BiOBr-O V Method for preparing nanocomposite materials.

[0041] (1) 10 g of sawdust sieved through 70 mesh was soaked in a 70 wt% H2SO4 solution with an 8% solid-to-liquid ratio. After stirring at room temperature for 3 h, an appropriate amount of deionized water was added to dilute the H2SO4 solution to 10 wt%. The mixture was then placed in an oven and kept at 160°C for 1.5 h. After cooling naturally, the resulting product was filtered and washed until neutral, and then dried at 140°C for 7 h. The dried sawdust was ground and sieved through 140 mesh, then transferred to a tube furnace under a nitrogen atmosphere and kept at 550°C for 1.5 h to obtain BC.

[0042] (2) Take 5.82g Bi(NO3)3·5H2O and dissolve it in 150mL ethylene glycol, and stir it continuously for 45min to obtain solution A3; take 0.79g BC and 1.43g KBr and dissolve them in 60mL ethylene glycol, and ultrasonicate them for 45min to obtain solution B3. Solution B3 was added dropwise to solution A3, and after stirring continuously for 1.5h, N2 was quickly filled into the solution and maintained for 15min. The resulting solution was then transferred to a hydrothermal reactor and kept warm at 250℃ for 20h. After natural cooling, the resulting product was washed with deionized water and ethanol, and centrifuged. Finally, it was dried in a vacuum environment at 70℃ for 7h to obtain 12BC-BiOBr-O with a total mass fraction of BC of 12%. V Nanocomposite materials.

[0043] Example 4

[0044] To test the photocatalytic activity, first prepare the concentration of 20 mg·L -1 TC solution and a concentration of 20 mg·L -1 RhB solution, add appropriate amount of BC-BiOBr-O V The nanocomposite material was added with 200mL 20mg·L -1 The TC or RhB reaction solution was placed in a 250 mL flat-bottom beaker. The pH of the solution was adjusted with a 0.1 M HCl / NaOH solution. A 300 W Xe lamp with a 420 nm filter was used as the light source. Under mechanical stirring at 300 rpm and circulating water, TC or RhB degradation by photocatalytic activation of PDS was performed. After a certain time interval (5 min), 2 mL of the reaction sample was collected with a syringe, the catalyst was filtered through a 0.22 μm water filter, and an equal volume of methanol was quickly added to terminate the degradation reaction. Finally, the collected reaction sample was measured by UV-Vis absorption at different times during the photocatalytic process to calculate the rate of TC or RhB degradation by photocatalytic activation of PDS. For recovery experiments, the catalyst sample was recovered by centrifugation, washed several times with distilled water, and then dried and stored.

[0045] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0046] The above descriptions are only preferred embodiments of the present invention. Any technical solution that achieves the purpose of the present invention by substantially the same means shall fall within the scope of protection of the present invention.

Claims

1. A BC-BiOBr-O V The method for preparing a nanocomposite material is characterized by: The preparation method uses a solvothermal method to combine biochar carbonized from sawdust with BiOBr rich in oxygen vacancies, thereby constructing BC-BiOBr-O with stable structure, large specific surface area, strong visible light response ability, high carrier separation efficiency and rich catalytic active sites. V The nanocomposite material, the specific steps of the preparation method are as follows: Step (1): After sieving sawdust at a certain mesh size, the sawdust is immersed in an appropriate amount of 60-90 wt.% H2SO4 solution at a certain solid-liquid ratio, and stirred at room temperature for 10-240 minutes to obtain a solid-liquid mixture; Step (2): adding an appropriate amount of deionized water to the solid-liquid mixture obtained in step (1) to dilute the solution to 5-50 wt.%, then transferring it to an oven, keeping it at a certain temperature for 20-240 minutes, letting it cool naturally, filtering and washing it until it is neutral, and then drying it at a certain temperature for 6-24 hours to obtain sawdust; Step (3): grinding the sawdust obtained in step (2), sieving it under certain mesh conditions, and finally transferring it to a tube furnace, heating it to a holding temperature under a nitrogen atmosphere, and keeping it at the holding temperature for 30-360 minutes to obtain BC; Step (4): dissolving a certain amount of Bi(NO3)3·5H2O in a certain amount of ethylene glycol solution and stirring continuously for 10-120 min to obtain a mixed solution; Step (5): dissolve a certain amount of KBr and the BC in step (3) in a certain amount of ethylene glycol solution and ultrasonicate for 10-120 min; Step (6): Add the solution obtained in step (5) dropwise to the mixed solution obtained in step (4), continue stirring for 30-360 min, and then quickly fill with N2 for a certain period of time; Step (7): The solution obtained in step (6) is transferred to a hydrothermal reactor, heated to a certain insulation temperature, and kept at the insulation temperature for 12-48 hours. After naturally cooling to room temperature, the sample is centrifuged and washed, and finally vacuum dried at a certain temperature for 6-24 hours to obtain BC-BiOBr-O V Nanocomposite materials.

2. A BC-BiOBr-O according to claim 1 V The method for preparing a nanocomposite material is characterized by: In step (1), the sawdust is screened to 30-90 mesh, and the solid-liquid ratio of the sawdust to the H2SO4 solution is 1-30%.

3. A BC-BiOBr-O according to claim 1 V The method for preparing a nanocomposite material is characterized by: The insulation temperature in step (2) is 80-300°C, and the drying temperature is 50-250°C.

4. A BC-BiOBr-O according to claim 1 V The method for preparing a nanocomposite material is characterized by: In step (3), the sawdust screening requirement is 60-150 mesh, and the insulation temperature is 400-800°C.

5. A BC-BiOBr-O according to claim 1 V The method for preparing a nanocomposite material is characterized by: The mass of Bi(NO3)3·5H2O used in step (4) is 1-20 g, and the volume of ethylene glycol is 30-600 mL.

6. A BC-BiOBr-O according to claim 1 V The method for preparing a nanocomposite material is characterized by: The mass of BC used in step (5) is 0-10 g, the mass of KBr is 0.1-10 g, and the volume of ethylene glycol is 10-400 mL.

7. A BC-BiOBr-O according to claim 1 V The method for preparing a nanocomposite material is characterized by: The time for filling N2 in step (6) is 1-30 minutes.

8. A BC-BiOBr-O according to claim 1 V The method for preparing a nanocomposite material is characterized by: The insulation temperature in step (7) is 120-400°C, and the vacuum drying temperature is 40-90°C.

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