A molecularly imprinted bismuth-based composite photocatalyst, its preparation method and application

Abstract

The present invention belongs to the technical field of environmental material preparation, and discloses a molecularly imprinted bismuth-based composite photocatalyst, a preparation method thereof and an application. Firstly, a composite metal material Bi / Ce is prepared by a liquid-phase reduction method. Secondly, a composite photocatalytic material Bi2O3 / CeO2 is prepared by high-temperature calcination and oxidation of Bi / Ce. Finally, molecular imprinting technology is used to photopolymerize POPD on the surface of Bi2O3 / CeO2 to prepare a molecularly imprinted photocatalyst POPD / Bi2O3 / CeO2 with selective recognition and degradation performance for pyridine, which can achieve efficient and selective degradation of pyridine in simulated oil. The molecularly imprinted photocatalytic material exhibits excellent performance in photocatalytic fuel denitrification. The preparation method of the present invention is simple to operate, the catalyst has high activity and stability, and has great application potential.

Description

Technical Field

[0001] The present invention belongs to the fuel denitrification technology in the petrochemical field, and specifically relates to a molecularly imprinted bismuth-based composite photocatalyst, a preparation method thereof, and an application thereof. Background Art

[0002] As one of the main energy sources for industrial development at the present stage, the clean use of petroleum remains a hot topic of concern. Oil products contain various nitrogen compounds, which are mainly divided into basic organic nitrogen and non-basic organic nitrogen. Basic organic nitrogen is represented by pyridine, such as pyridine, quinoline, acridine, etc., and non-basic nitrogen is represented by indole, such as pyrrole, indole, carbazole, etc. These nitrogen compounds not only seriously affect the stability of oil products, but also deepen their color and deteriorate their antioxidant properties. During storage, nitrogen compounds can also cause colloidal precipitation, affecting the storage and use performance of oil products. In addition, nitrogen oxide toxic gases will be released during the combustion process of oil products, causing serious harm to the environment. Therefore, the problem of oil product denitrification has become a hot topic of research in recent years. Among them, photocatalytic denitrification has attracted much attention because of its low cost and zero pollution.

[0003] Photocatalytic technology for oil product denitrification has the advantages of being safe, non-toxic, environmentally friendly, highly stable, highly catalytically active, and low energy consumption. However, there are few reports on molecularly imprinted photocatalytic fuel denitrification technology at present. This is mainly due to many challenges in the process of using solar energy for denitrification. There are mainly two aspects: one is the selective adsorption problem of nitrogen-containing compounds on the catalyst surface; the other is the low utilization rate of photocatalyst carriers. Based on this, it is very necessary to develop a new type of photocatalyst to achieve the selective adsorption of nitrogen-containing compounds and high solar energy utilization rate. Summary of the Invention

[0004] To solve the problems existing in the prior art, the purpose of the present invention is to provide a molecularly imprinted bismuth-based composite photocatalyst, a preparation method thereof, and an application thereof. The molecularly imprinted bismuth-based composite photocatalyst of the present invention can achieve the selective adsorption of nitrogen-containing compounds in oil products and has a relatively high solar energy utilization rate.

[0005] The technical solution adopted by the present invention:

[0006] A preparation method of a molecularly imprinted bismuth-based composite photocatalyst, comprising the following process:

[0007] Sodium borohydride aqueous solution is added to solution A, and solution A reacts with the sodium borohydride aqueous solution. After the reaction is completed, the precipitate is filtered, washed, and dried to obtain Bi / Ce powder; solution A is prepared by dissolving bismuth chloride and cerium chloride heptahydrate in water;

[0008] The Bi / Ce powder is calcined to generate Bi 2 O 3 / CeO2 ;

[0009] Dissolve Bi 2 O 3 / CeO 2 and polyethylene glycol 4000 in a solvent and perform ultrasonic treatment to modify Bi 2 O 3 / CeO 2 to obtain modified Bi 2 O 3 / CeO 2 ;

[0010] Add ethylene glycol dimethacrylate, azobisisobutyronitrile and modified Bi 2 O 3 / CeO 2 to solution B to obtain solution C, where solution B is prepared by dissolving pyridine and o-phenylenediamine in water;

[0011] Under a protective atmosphere, irradiate solution C with visible light to initiate polymerization. After the reaction is completed, filter, wash and dry to obtain reaction product A;

[0012] Add reaction product A to water, stir in an air atmosphere and irradiate with visible light to remove the pyridine template, then wash and dry to obtain the molecularly imprinted bismuth-based composite photocatalyst.

[0013] Preferably, when adding an aqueous solution of sodium borohydride to solution A, the aqueous solution of sodium borohydride is added dropwise to solution A;

[0014] The amount of sodium borohydride used is 1 - 3 g, and the molar ratio of bismuth chloride to cerium chloride heptahydrate is (1 - 5):1.

[0015] Preferably, when calcining the Bi / Ce powder, the calcination temperature is 500 - 700 °C and the calcination time is 1 - 5 h.

[0016] Preferably, the amount of Bi 2 O 3 / CeO 2 used is 1 - 3 g, the amount of polyethylene glycol 4000 used is 1 - 5 g, and the solvent is sufficient.

[0017] Preferably, the amount of pyridine used is 1 - 5 mmol, and the amount of o-phenylenediamine used is 1 - 5 mmol.

[0018] Preferably, the amount of ethylene glycol dimethacrylate used is 1 - 5 mL, and the amount of azobisisobutyronitrile used is 0.01 - 0.05 g.

[0019] Preferably, when initiating polymerization by irradiating solution C with visible light under a protective atmosphere, xenon lamp visible light irradiation is used for initiating polymerization, and the irradiation time is 10 - 30 min.

[0020] Preferably, when removing the pyridine template by visible light irradiation, the irradiation time for removing the pyridine template by xenon lamp visible light irradiation is 1 - 2 h.

[0021] The present invention also provides a molecularly imprinted bismuth - based composite photocatalyst, which is prepared by the preparation method as described above in the present invention.

[0022] The present invention also provides the application of the above - mentioned molecularly imprinted bismuth - based composite photocatalyst. The molecularly imprinted bismuth - based composite photocatalyst is used for photocatalytic degradation of nitrogen compounds in oil products, and the nitrogen compounds include pyridine.

[0023] The present invention has the following beneficial effects:

[0024] The present invention prepares a composite metal material Bi / Ce by a liquid - phase reduction method, and then prepares a composite photocatalytic material Bi 2 O 3 / CeO 2 by high - temperature calcination and oxidation of Bi / Ce. Finally, through a molecular imprinting method, a molecularly imprinted bismuth - based photocatalyst with selective degradation performance for nitrogen compounds (such as pyridine) in oil products is prepared, realizing the efficient and selective degradation of pyridine. The synthesis method of the present invention is simple, convenient and fast, greatly streamlining the synthesis steps. In the molecular imprinting technology, visible light is used to remove the template molecule, the method is novel and the operation is convenient, it is not easy to introduce impurities and the removal is complete. The whole process of the present invention is simple and easy to control, the production process is green and environmentally friendly, with low energy consumption, and can effectively achieve fuel denitrification under mild conditions, providing a potential solution to the environmental problems caused by nitrogen compounds in fuel, and having high application prospects.

[0025] The molecularly imprinted bismuth - based composite photocatalyst POPD / Bi 2 O 3 / CeO 2 of the present invention broadens the absorption edge band of Bi 2 O 3 / CeO 2 from 580 nm to 670 nm, and the band - gap width drops from 3.15 eV to 2.9 eV, greatly broadening its light absorption range and light absorption efficiency. The adsorption capacity of the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 is significantly better than that of other photocatalysts, such as Bi 2 O 3 and CeO 2and Bi 2 O 3 / CeO 2 。This is because there are a large number of imprinted cavities on the surface imprinted layer of the POPD / Bi 2 O 3 / CeO 2 molecularly imprinted composite photocatalyst. These cavities have the ability to selectively recognize the template molecule - pyridine, thus improving its adsorption performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the SEM spectrum of the molecularly imprinted bismuth-based composite photocatalyst prepared in Example 1 of the present invention.

[0027] Figure 2 This is the XRD spectrum of the molecularly imprinted bismuth-based composite photocatalyst prepared in Example 1 of the present invention and the composite photocatalytic material Bi 2 O 3 / CeO 2 .

[0028] Figure 3 This is the FT-IR spectrum of the molecularly imprinted bismuth-based composite photocatalyst prepared in Example 1 of the present invention, the composite photocatalytic material Bi 2 O 3 / CeO 2 and POPD.

[0029] Figure 4 This is the graph of the photocatalytic degradation rate of the molecularly imprinted bismuth-based composite photocatalyst prepared in Example 1 of the present invention, the photocatalyst Bi 2 O 3 / CeO 2 , the non-molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 for 50 mL of simulated oil containing 80 μg / g of pyridine.

[0030] Figure 5 This is the photocatalytic degradation performance graph of the non-molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 and the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 prepared in Example 1 of the present invention for different nitrogen-containing compounds. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be described in detail below with reference to the drawings and embodiments.

[0032] The following examples and comparative examples are only used to more clearly illustrate the technical solutions of the present invention, so that those skilled in the art can well understand and utilize the present invention, rather than limiting the protection scope of the present invention.

[0033] For the experimental methods, production processes, instruments and equipment involved in the examples and comparative examples of the present invention, their names and abbreviations are all conventional names in the art, and are very clear and definite in the relevant application fields. Those skilled in the art can understand the conventional process steps according to the names and apply the corresponding equipment, and implement them under conventional conditions or the conditions recommended by the manufacturer.

[0034] There are no special restrictions on the sources of various raw materials or reagents used in the examples and comparative examples of the present invention, and they are all conventional products that can be obtained by purchasing on the market.

[0035] The present invention uses BiCl 3 and CeCl 3 . 7H 2 O as raw materials to prepare Bi / Ce by liquid phase reduction method and then calcine it at high temperature to obtain the composite photocatalytic material Bi 2 O 3 / CeO 2 , and then prepare the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 through molecular imprinting technology.

[0036] The present invention selects to prepare Bi / Ce by liquid phase reduction method and calcine it at high temperature to obtain the composite photocatalytic material Bi 2 O 3 / CeO 2 . On the one hand, this method is based on its simple operation and short time consumption. On the other hand, this material has certain photocatalytic activity for pyridine.

[0037] Specifically, the preparation of the molecularly imprinted bismuth-based composite photocatalyst (POPD / Bi 2 O 3 / CeO 2 ) of the present invention includes the following steps:

[0038] (1) Preparation of Bi / Ce: Dissolve 1 - 3 g of sodium borohydride (NaBH 4 ) in 10 mL of distilled water to prepare a sodium borohydride solution, and then add bismuth chloride (BiCl 3 ) and cerium chloride heptahydrate (CeCl 3 . 7H 2O) Dissolve it in 200 mL of distilled water according to the dosage of 1:1 to 5:1 in molar ratio and transfer the solution to a three-necked flask. Place the three-necked flask in a water bath at 60 °C and stir the solution with a stirring rod. Then, drop the sodium borohydride solution into the three-necked flask. After the stirring reaction is complete, let it stand for suction filtration. Wash the precipitate several times with distilled water and absolute ethanol, then place it in an oven to dry. Subsequently, grind it with a mortar to obtain Bi / Ce powder.

[0039] (2) Preparation of Bi 2 O 3 / CeO 2 : Place the Bi / Ce powder prepared in step (1) in a muffle furnace and calcine it at 500 - 700 °C for 1 - 5 h. After cooling, Bi 2 O 3 / CeO 2 can be obtained.

[0040] (3) Preparation of molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 : Dissolve the Bi 2 O 3 / CeO 2 prepared in step (2) and polyethylene glycol 4000 in methanol and sonicate to modify Bi 2 O 3 / CeO 2 , where the dosages of Bi 2 O 3 / CeO 2 , polyethylene glycol 4000 and methanol are 1 - 3 g, 1 - 5 g, and 5 - 10 mL respectively. Then, dissolve 1 - 5 mmol of pyridine and 1 - 5 mmol of o-phenylenediamine in distilled water, add 1 - 5 mL of ethylene glycol dimethacrylate (EGDMA) and 0.01 - 0.05 g of azobisisobutyronitrile (AIBN), and add the modified Bi 2 O 3 / CeO 2 . Subsequently, transfer the above solution to a photocatalytic reaction flask and irradiate it with visible light from a xenon lamp for 10 - 30 min under nitrogen protection to initiate polymerization. After the reaction is completed, filter the solution and wash the precipitate several times with distilled water and absolute ethanol, then dry it. Finally, place the above product in a photocatalytic reaction flask, add 100 mL of distilled water, introduce air, turn on the magnetic stirrer, and irradiate it with visible light from a xenon lamp for 1 - 2 h to remove the pyridine template. Wash the precipitate several times with ethanol and distilled water, then put it in an oven to dry, and POPD (poly-o-phenylenediamine) / Bi 2 O 3 / CeO 2 can be obtained. 2 O 3 / CeO 2 Imprinted composite photocatalyst.

[0041] The POPD / Bi prepared in the present invention 2 O 3 / CeO 2 can be used as a molecularly imprinted photocatalyst and applied to photocatalytic fuel denitrification.

[0042] Example 1

[0043] The preparation of the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 includes the following steps:

[0044] (1) Dissolve 1.5 g of sodium borohydride (NaBH 4 ) in 10 mL of distilled water to form a sodium borohydride solution. Then dissolve bismuth chloride (BiCl 3 ) and cerium chloride heptahydrate (CeCl 3 . 7H 2 O) in 200 mL of distilled water according to a molar ratio of Bi to Ce of 4:1 and transfer the solution to a three-necked flask. Place the three-necked flask in a 60 °C water bath and stir the solution with a stirring rod. Then drop the sodium borohydride solution into the three-necked flask, stir for 1 h, and then let it stand for suction filtration. Wash the precipitate several times with distilled water and absolute ethanol and then dry it in an oven at 60 °C. Then grind it with a mortar to obtain Bi / Ce powder.

[0045] (2) Place the Bi / Ce powder obtained in step (1) in a muffle furnace and calcine it at 550 °C for 2 h to obtain Bi 2 O 3 / CeO 2 .

[0046] (3) Take 0.5 g of the Bi 2 O 3 / CeO 2 obtained in step (2) and dissolve it with 2.5 g of polyethylene glycol 4000 in 10 mL of methanol and ultrasonicate for 30 min to modify Bi 2 O 3 / CeO 2 to obtain modified Bi 2 O 3 / CeO 2 . Then dissolve 1 mmol of pyridine and 3 mmol of o-phenylenediamine in 15 mL of distilled water, add 2 mL of EGDMA and 0.05 g of AIBN, and add the modified Bi 2 O 3 / CeO2 , Subsequently, the above solution was transferred into a photocatalytic reaction flask and irradiated with visible light from a xenon lamp for 30 min under nitrogen protection to initiate polymerization. After the reaction, the solution was filtered, and the precipitate was washed several times with distilled water and absolute ethanol and then dried. Finally, the above product was placed in a photocatalytic reaction flask, 100 mL of distilled water was added, air was introduced, magnetic stirring was turned on, and the mixture was irradiated with visible light from a xenon lamp for 2 h to remove the pyridine template. The precipitate was washed three times with ethanol and distilled water and then dried in an oven at 60 °C to obtain the POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalytic material. Under the same conditions, a non-molecularly imprinted photocatalyst can be obtained without adding pyridine template molecules.

[0047] (4) Take the Bi 2 O 3 / CeO 2 at 1.6 g / L obtained in step (2), the POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalyst at 1.6 g / L and the non-imprinted photocatalyst at 1.6 g / L were respectively added to the pyridine-simulated oil for photocatalytic degradation experiments. The degradation rates of pyridine by each sample within 3 h were measured. Among them, the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 had the largest degradation rate for pyridine, reaching 80%. As Figure 4 , the degradation efficiencies of the three photocatalysts for pyridine all increased with the increase of irradiation time. When the irradiation time reached 120 min, the degradation rate tended to be stable and no longer increased. Among them, the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 had the largest degradation rate for pyridine, reaching 80%, showing strong photocatalytic activity and selectivity. It can be clearly seen from Figure 1 that the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 of the present invention has a lamellar structure in its morphology, thus having a large specific surface area and good photocatalytic activity.

[0048] From Figure 2 it can be seen that POPD / Bi 2 O 3 / CeO 2 and Bi 2 O 3 / CeO 2The characteristic diffraction peaks of Bi were all detected at 2θ = 24.6°, 25.8°, 32.6°, 36.0°, 40.7°, 49.6°, 54.4°, 68.3°, and 75.2°. 2 O 3 The characteristic diffraction peaks of CeO were detected at 2θ = 33.0°, 47.4°, 59.0°, and 76.6°. Compared with Bi 2 O 2 / CeO 3 In the XRD pattern of the POPD / Bi 2 O 2 / CeO 3 of the present invention, no other impurity peaks appeared, only the diffraction peak intensity decreased, indicating that during the synthesis of POPD / Bi 2 O 2 / CeO 3 the introduction of POPD did not destroy the crystal structures of Bi 2 O 2 and CeO 3 . 2

[0049] It can be seen from Figure 3 that the light absorption range of Bi 2 O 3 / CeO 2 mainly focuses on the ultraviolet light range of 200 nm to 370 nm, and the absorption edge is at 600 nm. In addition, the absorption edge of the POPD / Bi 2 O 3 / CeO 2 material is broadened from 580 nm to 670 nm, and its main absorption peak is located at about 320 nm, further indicating that the light absorption range of the composite material POPD / Bi 2 O 3 / CeO 2 is broadened, proving that the introduction of POPD enables the photocatalytic material to have better response in the visible light region.

[0050] It can be seen from Figure 4 that for the three photocatalysts ((a: Bi 2 O 3 / CeO 2 , b: non-molecularly imprinted photocatalytic POPD / Bi 2 O 3 / CeO 2 , c: molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2) The degradation efficiency of pyridine increases with the increase of light irradiation time. When the light irradiation time reaches 120 min, the degradation rate tends to be stable and no longer increases. Among them, the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 has the highest degradation rate of pyridine, reaching 80%, indicating that POPD / Bi 2 O 3 / CeO 2 has a high degradation rate for pyridine.

[0051] Figure 5 For the non-molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 and the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 The photocatalytic degradation performance for different nitrogen-containing compounds. It can be seen from Figure 5 that when there are multiple nitrogen-containing compounds in the system, the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 still has a high degradation ability for pyridine, and its degradation rate can reach 78%. The degradation ability for the other four interfering substances is lower than 50%. For the non-molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 the degradation abilities for the five nitrogen-containing compounds are quite the same. It can be seen from this that the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 has a high selective recognition performance for pyridine.

[0052] Example 2

[0053] The preparation of the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 in this example includes the following steps:

[0054] (1) Dissolve 2.5 g of sodium borohydride (NaBH 4 ) in 10 mL of distilled water to prepare a sodium borohydride solution. Then, bismuth chloride (BiCl 3 ) and cerium chloride heptahydrate (CeCl 3 . 7H 2(O) Dissolve according to a molar ratio of Bi to Ce of 1:1 in 200 mL of distilled water and transfer the solution to a three-necked flask. Place the three-necked flask in a water bath at 60 °C and stir the solution with a stirring rod. Subsequently, drop the sodium borohydride solution into the three-necked flask. After stirring for 1 h, let it stand and perform suction filtration. Wash the precipitate several times with distilled water and absolute ethanol, then place it in an oven and dry at 60 °C. Subsequently, grind it with a mortar to obtain Bi / Ce powder.

[0055] (2) Place the Bi / Ce powder obtained in step (1) in a muffle furnace and calcine it at 500 °C for 5 h to obtain Bi 2 O 3 / CeO 2 。

[0056] (3) Take 0.5 g of the Bi 2 O 3 / CeO 2 obtained in step (2) and dissolve it with 2.5 g of polyethylene glycol 4000 in 10 mL of methanol, and ultrasonicate for 30 min to modify Bi 2 O 3 / CeO 2 to obtain modified Bi 2 O 3 / CeO 2 。 Then dissolve 1 mmol of pyridine and 1 mmol of o-phenylenediamine in 15 mL of distilled water, add 1 mL of EGDMA and 0.01 g of AIBN, and add the modified Bi 2 O 3 / CeO 2 , then transfer the above solution into a photocatalytic reaction flask and irradiate it with visible light from a xenon lamp for 10 min under nitrogen protection to initiate polymerization. After the reaction, filter the solution, wash the precipitate several times with distilled water and absolute ethanol, and then dry it. Finally, place the above product in a photocatalytic reaction flask, add 100 mL of distilled water, pass in air, turn on the magnetic stirrer, and irradiate it with visible light from a xenon lamp for 1.5 h to remove the pyridine template. Wash the precipitate three times with ethanol and distilled water, then put it in an oven at 60 °C and dry it to obtain the POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalytic material. Under the same conditions, a non-molecularly imprinted photocatalyst can be obtained without adding pyridine template molecules.

[0057] (4) Take 1.6 g / L of the POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalyst obtained in step (3) and add it to the pyridine-simulated oil for its photocatalytic degradation experiment. The degradation rate of pyridine by the sample within 3 h is measured to be 81%.

[0058] Example 3

[0059] The molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 in this example is prepared by the following steps:

[0060] (1) Dissolve 1.0 g of sodium borohydride (NaBH 4 ) in 10 mL of distilled water to prepare a sodium borohydride solution. Then dissolve bismuth chloride (BiCl 3 ) and cerium chloride heptahydrate (CeCl 3 . 7H 2 O) in 200 mL of distilled water according to a molar ratio of Bi to Ce of 5:1 and transfer the solution to a three-necked flask. Place the three-necked flask in a water bath at 60 °C and stir the solution with a stirring rod. Then drop the sodium borohydride solution into the three-necked flask, stir for 1 h, and then let it stand for suction filtration. Wash the precipitate several times with distilled water and absolute ethanol and then dry it in an oven at 60 °C. Then grind it with a mortar to obtain Bi / Ce powder.

[0061] (2) Place the Bi / Ce powder obtained in step (1) in a muffle furnace and calcine it at 650 °C for 2 h to obtain Bi 2 O 3 / CeO 2 .

[0062] (3) Take 0.5 g of the Bi 2 O 3 / CeO 2 obtained in step (2) and dissolve it with 2.5 g of polyethylene glycol 4000 in 10 mL of methanol and ultrasonicate for 30 min to modify Bi 2 O 3 / CeO 2 to obtain modified Bi 2 O 3 / CeO 2 . Then dissolve 1 mmol of pyridine and 2 mmol of o-phenylenediamine in 15 mL of distilled water, add 5 mL of EGDMA and 0.03 g of AIBN, and add the modified Bi 2 O 3 / CeO 2, Subsequently, the above solution was transferred into a photocatalytic reaction flask and irradiated with visible light from a xenon lamp for 20 min under nitrogen protection to initiate polymerization. After the reaction, the solution was filtered, and the precipitate was washed several times with distilled water and anhydrous ethanol and then dried. Finally, the above product was placed in a photocatalytic reaction flask, 100 mL of distilled water was added, air was introduced, the magnetic stirrer was turned on, and the mixture was irradiated with visible light from a xenon lamp for 1 h to remove the pyridine template. The precipitate was washed three times with ethanol and distilled water and then dried in an oven at 60 °C to obtain POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalytic material. Under the same conditions, a non-molecularly imprinted photocatalyst can be obtained without adding pyridine template molecules.

[0063] (4) Take the POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalyst at 1.6 g / L and add it to the pyridine-simulated oil for its photocatalytic degradation experiment. The degradation rate of pyridine by the sample within 3 h was measured to be 82%.

[0064] Example 4

[0065] The preparation of the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 in this example includes the following steps:

[0066] (1) Dissolve 1.5 g of sodium borohydride (NaBH 4 ) in 10 mL of distilled water to prepare a sodium borohydride solution. Then, dissolve bismuth chloride (BiCl 3 ) and cerium chloride heptahydrate (CeCl 3 . 7H 2 O) in 200 mL of distilled water according to the molar ratio of Bi to Ce of 3:1, transfer the solution to a three-necked flask, place the three-necked flask in a water bath at 60 °C, and stir the solution with a stir bar. Subsequently, the sodium borohydride solution was dropped into the three-necked flask, stirred for 1 h, and then left to stand for suction filtration. The precipitate was washed several times with distilled water and anhydrous ethanol and then dried in an oven at 60 °C, and then ground with a mortar to obtain Bi / Ce powder.

[0067] (2) Place the Bi / Ce powder obtained in step (1) in a muffle furnace and calcine it at 700 °C for 1 h to obtain Bi 2 O 3 / CeO 2 .

[0068] (3) Place the Bi 2 O 3 / CeO 2 Dissolve 0.5 g and 2.5 g of polyethylene glycol 4000 in 10 mL of methanol and ultrasonically treat for 30 min for Bi 2 O 3 / CeO 2 modification to obtain modified Bi 2 O 3 / CeO 2 After that, dissolve 1 mmol of pyridine and 5 mmol of o-phenylenediamine in 15 mL of distilled water, add 4 mL of EGDMA and 0.04 g of AIBN, and add the modified Bi 2 O 3 / CeO 2 , then transfer the above solution into a photocatalytic reaction flask and irradiate it with visible light from a xenon lamp for 25 min under nitrogen protection to initiate polymerization. After the reaction, filter the solution and wash the precipitate several times with distilled water and absolute ethanol, and then dry it. Finally, place the above product in a photocatalytic reaction flask and add 100 mL of distilled water. After introducing air, turn on the magnetic stirrer and irradiate it with visible light from a xenon lamp for 80 min to remove the pyridine template. Wash the precipitate three times with ethanol and distilled water and then dry it in an oven at 60 °C to obtain the POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalytic material. Under the same conditions, a non-molecularly imprinted photocatalyst can be obtained without adding pyridine template molecules.

[0069] (4) Take the POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalyst at 1.6 g / L and add it to the pyridine-simulated oil for its photocatalytic degradation experiment. The degradation rate of pyridine by the sample within 3 h is measured to be 81%.

[0070] Example 5

[0071] The preparation of the molecularly imprinted photocatalyst POPD / Bi 2 O 3 / CeO 2 in this example includes the following steps:

[0072] (1) Dissolve 2 g of sodium borohydride (NaBH 4 ) in 10 mL of distilled water to prepare a sodium borohydride solution. Then, bismuth chloride (BiCl 3 ) and cerium chloride heptahydrate (CeCl 3 . 7H 2(O) Dissolve according to a molar ratio of Bi to Ce of 2:1 in 200 mL of distilled water and transfer the solution to a three-necked flask. Place the three-necked flask in a water bath at 60 °C and stir the solution with a stir bar. Subsequently, drop the sodium borohydride solution into the three-necked flask. After stirring for 1 h, let it stand and filter by suction. Wash the precipitate several times with distilled water and absolute ethanol and then dry it in an oven at 60 °C. Subsequently, grind it with a mortar to obtain Bi / Ce powder.

[0073] (2) Place the Bi / Ce powder obtained in step (1) in a muffle furnace and calcine it at 600 °C for 4 h to obtain Bi 2 O 3 / CeO 2 。

[0074] (3) Take 0.5 g of the Bi 2 O 3 / CeO 2 obtained in step (2) and dissolve it with 2.5 g of polyethylene glycol 4000 in 10 mL of methanol. Ultrasonic for 30 min to modify Bi 2 O 3 / CeO 2 to obtain modified Bi 2 O 3 / CeO 2 。 Then dissolve 1 mmol of pyridine and 4 mmol of o-phenylenediamine in 15 mL of distilled water, add 3 mL of EGDMA and 0.02 g of AIBN, and add the modified Bi 2 O 3 / CeO 2 . Subsequently, transfer the above solution into a photocatalytic reaction flask and irradiate it with visible light from a xenon lamp for 15 min under nitrogen protection to initiate polymerization. After the reaction is completed, filter the solution and wash the precipitate several times with distilled water and absolute ethanol and then dry it. Finally, place the above product in a photocatalytic reaction flask and add 100 mL of distilled water. After introducing air, turn on the magnetic stirrer and irradiate it with visible light from a xenon lamp for 100 min to remove the pyridine template. Wash the precipitate three times with ethanol and distilled water and then dry it in an oven at 60 °C to obtain the POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalytic material. Under the same conditions, a non-molecularly imprinted photocatalyst can be obtained without adding pyridine template molecules.

[0075] (4) Take 1.6 g / L of the POPD / Bi 2 O 3 / CeO 2 imprinted composite photocatalyst obtained in step (3) and add it to the pyridine-simulated oil for its photocatalytic degradation experiment. The degradation rate of the sample for pyridine within 3 h is measured to be 83%.

Claims

1. Preparation method of a molecularly imprinted bismuth-based composite photocatalyst, characterized in that, it includes the following processes: Sodium borohydride aqueous solution is added to solution A, and solution A reacts with the sodium borohydride aqueous solution. After the reaction ends, the precipitate is filtered, washed, and dried to obtain Bi / Ce powder; solution A is prepared by dissolving bismuth chloride and cerium chloride heptahydrate in water; Calcine the Bi / Ce powder to produce Bi 2 O 3 / CeO 2 ; Dissolve Bi 2 O 3 / CeO 2 and polyethylene glycol 4000 in a solvent and perform ultrasonic treatment to modify Bi 2 O 3 / CeO 2 to obtain modified Bi 2 O 3 / CeO 2 ; Add ethylene glycol dimethacrylate, azobisisobutyronitrile and modified Bi to Solution B 2 O 3 / CeO 2 to obtain Solution C, where Solution B is prepared by dissolving pyridine and o-phenylenediamine in water; Under a protective atmosphere, solution C is irradiated with visible light for initiation polymerization. After the reaction ends, filtration, washing, and drying are carried out to obtain reaction product A; Reaction product A is added to water, stirred in an air atmosphere, and irradiated with visible light at the same time to remove the pyridine template. Then, washing and drying are carried out to obtain the molecularly imprinted bismuth-based composite photocatalyst.

2. The preparation method of a molecularly imprinted bismuth-based composite photocatalyst according to claim 1, characterized in that, when adding the sodium borohydride aqueous solution to solution A, the sodium borohydride aqueous solution is added dropwise to solution A; the dosage of sodium borohydride is 1 - 3 g, and the molar ratio of bismuth chloride to cerium chloride heptahydrate is (1 - 5):

1.

3. The preparation method of a molecularly imprinted bismuth-based composite photocatalyst according to claim 1, characterized in that, when calcining the Bi / Ce powder, the calcination temperature is 500 - 700 °C, and the calcination time is 1 - 5 h.

4. The preparation method of a molecularly imprinted bismuth-based composite photocatalyst according to claim 1, characterized in that, Bi 2 O 3 / CeO 2 The dosage of Bi 2 O 3 / CeO 2 is 1 to 3 g, the dosage of polyethylene glycol 4000 is 1 to 5 g, and the solvent is sufficient.

5. The preparation method of a molecularly imprinted bismuth-based composite photocatalyst according to claim 1, characterized in that, the dosage of pyridine is 1 - 5 mmol, and the dosage of o-phenylenediamine is 1 - 5 mmol.

6. The preparation method of a molecularly imprinted bismuth-based composite photocatalyst according to claim 1, characterized in that, the dosage of ethylene glycol dimethacrylate is 1 - 5 mL, and the dosage of azobisisobutyronitrile is 0.01 - 0.05 g.

7. The preparation method of a molecularly imprinted bismuth-based composite photocatalyst according to claim 1, characterized in that, when irradiating solution C with visible light for initiation polymerization under a protective atmosphere, it is irradiated with visible light from a xenon lamp for initiation polymerization under a protective atmosphere, and the irradiation time is 10 - 30 min.

8. The preparation method of a molecularly imprinted bismuth-based composite photocatalyst according to claim 1, characterized in that, when irradiating with visible light to remove the pyridine template, it is irradiated with visible light from a xenon lamp to remove the pyridine template, and the irradiation duration is 1 - 2 h.

9. A molecularly imprinted bismuth-based composite photocatalyst, characterized in that, this molecularly imprinted bismuth-based composite photocatalyst is prepared by the preparation method described in any one of claims 1 - 8.

10. Application of the molecularly imprinted bismuth-based composite photocatalyst according to claim 9, characterized in that, the molecularly imprinted bismuth-based composite photocatalyst is used for photocatalytic degradation of nitrogen compounds in oil products, and the nitrogen compounds include pyridine.

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