Preparation method and application of polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst
By preparing polyvinyl chloride hydrothermal carbon/bismuth vanadate heterojunction photocatalyst, the problem of photogenerating electrons and photogenerating holes of BiVO4 photocatalyst is solved, and the effect of efficient degradation of organic pollutants is achieved. The material is low in cost and can be reused, and it is suitable for water treatment.
Patent Information
- Application Number
- CN202510409159.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2025-07-11
AI Technical Summary
In the photocatalyst, photogenerated electrons and photogenerated holes are easily recombined during the photocatalysis process, resulting in difficulty in efficient use of photogenerated carriers, low pollutant removal rate, and existing heterojunction composite materials have high costs and metal ion leakage problems.
The preparation method of polyvinyl chloride hydrothermal carbon/bismuth vanadate heterojunction photocatalyst is adopted to synthesize heterojunction between polyvinyl chloride hydrothermal carbon and bismuth vanadate through hydrothermal reaction, and use the unique sheet-like structure and energy band structure of polyvinyl chloride hydrothermal carbon to form heterojunction with BiVO4, which improves the separation and transmission of photogenerated electrons and photogenerated holes, and degrades organic pollutants.
The degradation efficiency of organic pollutants in visible light is 98.03% and 96.41% of the degradation efficiency of acetaminophen and 2,4-dichlorophenol respectively. The material is cheap and reusable, and there is no secondary pollution after degradation, and it has broad application prospects.
Smart Images
Figure CN120285970A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a preparation method and application of a polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst, belonging to the technical field of semiconductor photocatalytic materials and their preparation. Background Art
[0002] To ensure water safety, advanced oxidation processes are increasingly used to rapidly and efficiently degrade some refractory organic pollutants in water bodies. Due to the use of abundant sunlight as the only energy input, photocatalytic degradation of pollutants is considered one of the most sustainable, cost-effective, and promising advanced oxidation processes, which can degrade pollutants into small molecules or mineralize them into CO2 and H2O under mild reaction conditions.
[0003] Semiconductor photocatalysis has the advantages of strong oxidation ability, complete mineralization of pollutants, and direct utilization of sunlight. In the reaction, the photocatalyst mainly generates electron-hole pairs under light irradiation, and the separation and transport of photoexcited electrons and holes lead to the generation of active substances, achieving the effect of degrading organic pollutants.
[0004] Bismuth vanadate (BiVO4) has a low band gap energy, good dispersibility, non-toxicity, and corrosion resistance, and has the advantage of using sunlight to degrade pollutants. Using it as a visible light photocatalyst to degrade pollutants in water is an ideal method. However, the photoexcited electrons and holes generated by BiVO4 prepared by traditional methods are prone to recombination during the photocatalytic process, and the photoexcited carriers are difficult to be effectively utilized, resulting in a low removal rate of pollutants, which limits the practical application of BiVO4 in the field of water treatment.
[0005] Preparing a BiVO4 heterojunction composite material is an effective method to improve the separation of photoexcited electrons and holes. After BiVO4 is combined with a semiconductor, a heterojunction can be formed at the interface of the combination, causing the mutual transfer of photoexcited carriers between semiconductors, and effectively separating photoexcited electrons and holes. However, most of the existing heterojunction composite materials are composites of metals or metal oxides and BiVO4, which have problems such as high cost and metal ion leakage. Summary of the Invention
[0006] The present invention aims to solve the above problems existing in the prior art, and provides a preparation method and application of a polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst.
[0007] The technical solution of the present invention:
[0008] One of the objectives of the present invention is to provide a preparation method of a polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst. The preparation method is as follows: Using bismuth nitrate pentahydrate, ammonium metavanadate, and polyvinyl chloride powder as raw materials, and water as a solvent, a hydrothermal reaction is carried out. After the reaction is completed, it is cooled to room temperature, the precipitate is collected, washed, dried, and ground to obtain the polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst.
[0009] Further defined, the molar ratio of bismuth nitrate pentahydrate to ammonium metavanadate is 2:1 to 1:2.
[0010] Further defined, the mass ratio of bismuth nitrate pentahydrate to polyvinyl chloride is 15:1 to 2:1.
[0011] Further defined, the dosage ratio of bismuth nitrate pentahydrate to water is 2 mmol: 20 mL.
[0012] Further defined, the hydrothermal reaction temperature is 180 - 250 °C, and the time is 5 - 7 h.
[0013] Further defined, the collected precipitate is washed multiple times by alternately washing with deionized water and absolute ethanol.
[0014] Further defined, the drying temperature is 50 - 70 °C.
[0015] Another objective of the present invention is to provide a polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst prepared by the above method.
[0016] Another objective of the present invention is to provide an application of the above polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst, specifically for removing organic pollutants in wastewater.
[0017] Further defined, the organic pollutants are paracetamol or 2,4-dichlorophenol.
[0018] Further defined, the specific application method is as follows: Mix the polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst with the organic pollutant wastewater to be treated, stir in a dark and light-shielded environment. After reaching the adsorption-desorption equilibrium, transfer it to a visible light condition for photocatalytic reaction to achieve the degradation of organic pollutants in the wastewater.
[0019] The beneficial effects of the present invention:
[0020] (1) The present invention uses bismuth nitrate pentahydrate, ammonium metavanadate, and polyvinyl chloride powder as raw materials, and water as a solvent. A polyvinyl chloride hydrothermal carbon / BiVO4 heterojunction photocatalyst with low cost, high degradation efficiency, strong reusability, simple operation, and good practicability is synthesized by a simple hydrothermal method. This catalyst generates photoexcited electron-hole pairs under visible light. The separation and transmission of photoexcited electrons and holes lead to the generation of active substances, achieving the effect of degrading organic pollutants and being able to effectively treat organic pollutants such as acetaminophen and 2,4-dichlorophenol in water. The test results show that the degradation efficiency of acetaminophen is as high as 98.03% within 20 minutes, and the degradation efficiency of 2,4-dichlorophenol is as high as 96.41% within 25 minutes.
[0021] (2) The present invention utilizes the unique flaky structure of polyvinyl chloride hydrothermal carbon to provide a basis for the loading of BiVO4, and forms a heterojunction by fitting the unique energy band structure of polyvinyl chloride hydrothermal carbon with BiVO4. It makes full use of the photoexcited electrons on the conduction band of polyvinyl chloride hydrothermal carbon and the photoexcited holes on the valence band of BiVO4, enabling the heterojunction to have superior redox ability. While improving the photocatalytic performance, the successful construction of this heterojunction enables photoexcited electrons and photoexcited holes to be separated and migrated more effectively. This separation process significantly enhances the efficiency of the photocatalytic reaction. The test results show that it can catalytically degrade acetaminophen and 2,4-dichlorophenol under visible light, and the degradation efficiency is above 95% in both cases. It can degrade organic pollutants into non-toxic and harmless small molecules, and there is no secondary pollution after degradation, having broad application prospects.
[0022] (3) The raw materials used in this application are bismuth nitrate pentahydrate, ammonium metavanadate, and polyvinyl chloride, etc. These materials are all inexpensive and easy to obtain, and waste polyvinyl chloride can be used as a raw material to "turn waste into treasure" for polyvinyl chloride, which is a method for the upgrading and transformation of waste polyvinyl chloride. In addition, the preparation method provided by the present invention is simple and easy to operate, greatly reducing the cost. The prepared material has reusability and extremely high application value. Description of the Drawings
[0023] Figure 1 (a) in it is the SEM image of the BiVO4 monomer photocatalyst B2 prepared in Comparative Example 2, (b) is the SEM image of the polyvinyl chloride hydrothermal carbon material B1 prepared in Comparative Example 1, and (c) is the SEM image of the photocatalyst A2 prepared in Example 2;
[0024] Figure 2 is the HRTEM image of the photocatalyst A2 prepared in Example 2;
[0025] Figure 3Degradation effect diagrams of the photocatalysts prepared in Examples 1 to 3, the polyvinyl chloride hydrothermal carbon material B1 prepared in Comparative Example 1, and the BiVO4 monomer photocatalyst B2 prepared in Comparative Example 2 for paracetamol within the same illumination time;
[0026] Figure 4 Degradation effect diagrams of the photocatalysts prepared in Examples 1 to 3, the polyvinyl chloride hydrothermal carbon material B1 prepared in Comparative Example 1, and the BiVO4 monomer photocatalyst B2 prepared in Comparative Example 2 for 2,4-dichlorophenol within the same illumination time. Detailed implementation manners
[0027] To make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific implementation manners of the present invention is made in conjunction with the embodiments of the specification.
[0028] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.
[0029] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that can be included in at least one implementation manner of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that are mutually exclusive with other embodiments.
[0030] The experimental methods used in the following embodiments are all conventional methods unless otherwise specified. The materials, reagents, methods and instruments used, unless otherwise specified, are all conventional materials, reagents, methods and instruments in the art, and those skilled in the art can obtain them through commercial channels.
[0031] Example 1
[0032] Put 2 mmol of bismuth nitrate pentahydrate and 2 mmol of ammonium metavanadate into a 50 mL beaker, add 20 mL of deionized water, then add 75 mg of polyvinyl chloride powder, and place the beaker on a magnetic stirrer and stir for 20 min. Then transfer the obtained uniform solution to a 50 mL reaction kettle with a PPL liner, and place it in a muffle furnace and heat at 200 °C for 5 h. After the reaction is completed, cool to room temperature, take out the product in the reaction kettle, centrifuge to collect the obtained precipitate, wash it alternately with deionized water and absolute ethanol 3 times, and place the washed solid in a vacuum drying oven and dry at 60 °C for 24 h. Grind the dried solid to obtain a polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst, named A1.
[0033] Example 2
[0034] The difference between this example and Example 1 is that the addition amount of polyvinyl chloride powder is 150 mg, so that the mass ratio of polyvinyl chloride to bismuth nitrate pentahydrate is 1:7. The remaining process steps and parameter settings are the same as those in Example 1. The obtained polyvinyl chloride hydrothermal carbon / BiVO4 heterojunction photocatalyst is named A2.
[0035] Example 3
[0036] The difference between this example and Example 1 is that the addition amount of polyvinyl chloride powder is 300 mg, so that the mass ratio of polyvinyl chloride to bismuth nitrate pentahydrate is 1:3.5. The remaining process steps and parameter settings are the same as those in Example 1. The obtained polyvinyl chloride hydrothermal carbon / BiVO4 heterojunction photocatalyst is named A3.
[0037] Comparative Example 1
[0038] Place 150 mg of polyvinyl chloride powder in a 50 mL beaker, add 20 mL of deionized water, and place the beaker on a magnetic stirrer and stir for 20 min. Then transfer the obtained homogeneous solution to a 50 mL reaction kettle with a PPL liner, and place it in a muffle furnace and heat at 200 °C for 5 h. After the reaction is completed, cool to room temperature, take out the product in the reaction kettle, centrifuge to collect the obtained precipitate, wash it alternately with deionized water and absolute ethanol 3 times, and place the washed solid in a vacuum drying oven and dry at 60 °C for 24 h. Grind the dried solid to obtain a polyvinyl chloride hydrothermal carbon material, named B1.
[0039] Comparative Example 2
[0040] Put 2 mmol of bismuth nitrate pentahydrate and 2 mmol of ammonium metavanadate in a 50 mL beaker, add 20 mL of deionized water, and place the beaker on a magnetic stirrer and stir for 20 min. Then transfer the obtained homogeneous solution to a 50 mL reaction kettle with a PPL liner, and place it in a muffle furnace and heat at 200 °C for 5 h. After the reaction is completed, cool to room temperature, take out the product in the reaction kettle, centrifuge to collect the obtained precipitate, wash it alternately with deionized water and absolute ethanol 3 times, and place the washed solid in a vacuum drying oven and dry at 60 °C for 24 h. Grind the dried solid to obtain a BiVO4 monomer photocatalyst, named B2.
[0041] Effect Example
[0042] Characterize the structures and performances of the photocatalysts prepared in Examples 1 to 3 and Comparative Examples 1 to 2, which are specifically described as follows.
[0043] (1) Figure 1SEM images of the photocatalyst A2 prepared in Example 2, the polyvinyl chloride hydrothermal carbon material B1 prepared in Comparative Example 1, and the BiVO4 monomer photocatalyst B2 prepared in Comparative Example 2. Among them, (a) is the SEM image of the BiVO4 monomer photocatalyst B2 prepared in Comparative Example 2, (b) is the SEM image of the polyvinyl chloride hydrothermal carbon material B1 prepared in Comparative Example 1, and (c) is the SEM image of the photocatalyst A2 prepared in Example 2. From Figure 1 it can be seen that BiVO4 crystal grains in A2 grow on the surface of the polyvinyl chloride hydrothermal carbon and are evenly distributed.
[0044] (2) Figure 2 HRTEM image of the photocatalyst A2 prepared in Example 2. From Figure 2 the formation of the polyvinyl chloride hydrothermal carbon / BiVO4 heterojunction interface can be seen, which indicates the successful synthesis of the polyvinyl chloride hydrothermal carbon / BiVO4 heterojunction.
[0045] (3) Test the degradation of the pollutant paracetamol by the photocatalysts prepared in Examples 1 to 3 and Comparative Examples 1 to 2.
[0046] Specifically, weigh 25 mg each of the polyvinyl chloride hydrothermal carbon material B1 prepared in Comparative Example 1, the BiVO4 material B2 prepared in Comparative Example 2, and the polyvinyl chloride hydrothermal carbon / BiVO4 heterojunction photocatalysts (A1, A2, and A3) obtained in Examples 1 to 3, and add them to 50 mL of a paracetamol aqueous solution respectively, where the concentration of paracetamol is 1 mg / L.
[0047] Magnetically stir the mixed solution of the catalyst and the paracetamol solution for 15 min under dark conditions. After reaching the adsorption-desorption equilibrium, carry out the photocatalytic reaction under visible light simulated by a xenon lamp with a 420 nm ultraviolet filter. Take samples at regular intervals. The photocatalytic reaction is carried out for 20 min. Finally, analyze the taken water samples by a DGLC-U3000 liquid chromatograph to measure the concentration of paracetamol after photocatalysis. The degradation efficiency of different photocatalysts for paracetamol is as Figure 3 shown.
[0048] Set a blank group: Take 50 mL of a paracetamol solution with a concentration of 1 mg / L, do not add any catalyst material, and carry out the photocatalytic reaction under the same experimental conditions as the experimental group with the added catalyst as a control.
[0049] From Figure 3 it can be seen that the polyvinyl chloride hydrothermal carbon / BiVO4 heterojunction photocatalysts prepared in Examples 1 to 3 of the present invention have good degradation effects on paracetamol, and the photocatalyst prepared in Example 2 has the best degradation effect, specifically reaching 98.03%.
[0050] (4) Test the degradation of 2,4-dichlorophenol in pollutants by the photocatalysts prepared in Test Examples 1-3 and Comparative Examples 1-2.
[0051] Specifically, weigh 25 mg each of the polyvinyl chloride hydrothermal carbon material B1 prepared in Comparative Example 1, the BiVO4 material B2 prepared in Comparative Example 2, and the polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalysts (A1, A2, and A3) obtained in Test Examples 1-3, and add them to 50 mL of a 2,4-dichlorophenol aqueous solution with a 2,4-dichlorophenol concentration of 10 mg / L.
[0052] Magnetically stir the mixed solution of the catalyst and the 2,4-dichlorophenol solution in the dark for 15 min. After reaching the adsorption-desorption equilibrium, carry out the photocatalytic reaction under visible light simulated by a xenon lamp with a 420 nm ultraviolet filter. Take samples at regular intervals. After 20 min of photocatalytic reaction, finally analyze the water samples taken by a DGLC-U3000 liquid chromatograph to measure the concentration of 2,4-dichlorophenol after photocatalysis. The degradation efficiency of 2,4-dichlorophenol by different photocatalysts is as Figure 4 shown.
[0053] Set up a blank group: Take 50 mL of a 2,4-dichlorophenol solution with a concentration of 10 mg / L, without adding any catalyst material, and carry out the photocatalytic reaction under the same experimental conditions as the experimental group with the added catalyst as a control.
[0054] From Figure 4 it can be seen that the photocatalysts prepared in Test Examples 1-3 have good effects on degrading 2,4-dichlorophenol, and the photocatalyst prepared in Test Example 2 has the best degradation effect, specifically reaching 96.41%.
[0055] The above are only the preferred embodiments of the present invention. In view of the fact that those skilled in the art to which the present invention pertains can make appropriate changes and modifications to the above-mentioned embodiments, therefore, the present invention is not limited to the specific embodiments described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention.
Claims
1. A preparation method of a polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst, characterized in that, The preparation method is as follows: Using bismuth nitrate pentahydrate, ammonium metavanadate and polyvinyl chloride powder as raw materials, and water as a solvent, a hydrothermal reaction is carried out. After the reaction is completed, it is cooled to room temperature, the precipitate is collected, washed, dried, and ground to obtain a polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst.
2. The preparation method according to claim 1, wherein, The molar ratio of bismuth nitrate pentahydrate to ammonium metavanadate is 2:1 to 1:
2.
3. The preparation method according to claim 1, characterized in that, The mass ratio of bismuth nitrate pentahydrate to polyvinyl chloride is 15:1 to 2:
1.
4. The preparation method according to claim 1, characterized in that, The dosage ratio of bismuth nitrate pentahydrate to water is 2 mmol: 20 mL.
5. The preparation method according to claim 1, wherein The hydrothermal reaction temperature is 180 - 250 °C, and the time is 5 - 7 h.
6. The preparation method according to claim 1, characterized in that, The collected precipitate is washed multiple times by alternately washing with deionized water and absolute ethanol.
7. The preparation method according to claim 1, characterized in that, The drying temperature is 50 - 70 °C.
8. A polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst prepared by the method according to any one of claims 1 to 7.
9. Application of the polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst according to claim 8, characterized in that, It is used to remove organic pollutants in wastewater.
10. Use of the polyvinyl chloride hydrothermal carbon / bismuth vanadate heterojunction photocatalyst according to claim 9, characterized in that, The organic pollutant is paracetamol or 2,4-dichlorophenol.