Preparation method and application of two-dimensional bismuth-based surface molecular imprinting photocatalyst

Abstract

The invention discloses a preparation method and application of a two-dimensional bismuth-based surface molecular imprinting photocatalyst. Template molecule venlafaxine and functional monomer 2-acrylamide-2-methylpropanesulfonic acid are dissolved in an ethanol solvent containing a carrier BiOCl, prepolymerization is performed at 20-40 DEG C for 2-8 h, and the two-dimensional bismuth-based surface molecular imprinting photocatalyst is obtained. Adding ethylene glycol dimethacrylate serving as a cross-linking agent and azodiisobutyronitrile serving as an initiator, performing thermal polymerization for 20-30 hours at the temperature of 50-70 DEG C after ultrasonic and nitrogen charging protection, and performing elution and drying to obtain the two-dimensional bismuth-based surface molecular imprinting photocatalyst. The imprinted photocatalyst prepared by the invention has strong capability of selectively adsorbing a target object venlafaxine in an aqueous solution, the venlafaxine is preferentially and rapidly degraded under an illumination condition, and the imprinted photocatalyst can be used for selective photocatalytic removal of the venlafaxine in an actual water sample.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of functional macromolecular polymers, and specifically relates to a preparation method and application of a two-dimensional bismuth-based surface molecular imprinting photocatalyst. Background Art

[0002] Heterogeneous photocatalysis is a completely green advanced oxidation technology that can rapidly oxidize and decompose a variety of pollutants in water without selectivity. However, the active species produced by photocatalysis have a short life span and are non-selective. In actual water bodies, pollutants are complex in composition, and high concentrations of non-toxic soluble organic matter and various inorganic ions often coexist with low concentrations of target substances. The coexisting pollutants will form competitive adsorption on the catalyst surface and be preferentially degraded, resulting in a large number of active species being ineffectively consumed. The number of active species allocated to target pollutants is limited, resulting in relatively poor removal effects.

[0003] Molecularly imprinted polymers (MIPs) are adsorbent materials with selective recognition capabilities. Under the induction of template molecules, the material copolymerizes with functional monomers to form imprinted cavities containing "specific recognition sites", and synergizes the dual effects of functional monomer binding sites and structural complementary cavities to achieve the selective adsorption of target pollutants in complex water environments, achieving the purpose of separating and enriching low-concentration target pollutants. However, as an adsorbent material, molecularly imprinted polymers only physically transfer pollutants to remove pollutants, and cannot decompose pollutants into non-toxic substances. In addition, eluting the adsorbed molecularly imprinted polymers consumes a large amount of toxic organic solvents, which is costly and easy to cause secondary pollution.

[0004] Combining molecular imprinted polymers with photocatalytic materials and constructing molecular recognition cavities on or near the catalytic active sites of photocatalysts can enable photocatalysts to accurately identify target pollutants under complex matrix conditions and enrich target pollutants on or near the catalytic active sites. Under light conditions, various active species produced by the catalyst can focus on attacking target pollutants, efficiently degrading toxic chemicals into non-toxic products, and achieving thorough removal of target pollutants in a preferential manner. In the preparation process, the photocatalyst acts as a carrier, and its morphological structure directly affects the adsorption properties of the imprinted polymer. The thickness of the imprinted polymer coating layer determines the catalytic performance of the imprinted photocatalyst.

[0005] Patent document with publication number CN111234295B discloses a method for preparing a molecular imprinted photocatalytic material, comprising mixing a template molecule, a functional monomer and a porogen to carry out a prepolymerization reaction to obtain a prepolymer; mixing the prepolymer, a crosslinking agent, an initiator and BiOBr, and carrying out a polymerization reaction under protective atmosphere conditions to obtain a polymer; eluting the polymer to obtain the molecular imprinted photocatalytic material, the elution method being calcination, the calcination temperature being 400~500℃, and the calcination time being 2~4h. The patent document has the following three deficiencies: First, the solvent used in the preparation process is non-polar solvent acetonitrile or methanol. Although these solvents are commonly used solvents in the molecular imprinting preparation process, they are not environmentally friendly and are prone to secondary pollution. Using polar solvent ethanol as a solvent is relatively green, but polar solvent ethanol usually affects the combination of functional monomers and template molecules, and it is not easy to prepare molecular imprinting polymers; second, the calcination elution method is used in the process of removing the template molecules, which requires a relatively high temperature and consumes a lot of energy. The elution effect with methanol is not good; third, from the analysis of the selectivity effect, the selectivity of the prepared molecular imprinting polymer is not obvious enough, which may be because the molecular structure of the imprinting site is destroyed during the calcination process, so that the imprinting cavity cannot match the structure of the target pollutant, resulting in non-target pollutants entering the imprinting cavity.

[0006] During the preparation of molecular imprinted polymers, the elution effect of the template molecules directly affects the adsorption performance and selectivity of the molecular imprinted catalytic material. The high-temperature calcination method used in the above patent literature to elute the template molecules not only consumes a lot of energy, but also causes the molecular imprinted polymer to degrade due to excessively high temperature, thereby destroying the imprinted cavity structure, resulting in a mismatch between the imprinted cavity and the spatial structure of the template pollutant, and thus causing a decrease in selectivity. In the process of preparing MIPs, it is also very important to choose a suitable solvent, which not only affects the effect of the polymerization reaction, but also affects the performance of the final product MIPs. Considering environmental protection and production safety issues, the selected solvent is preferably low in toxicity to reduce the impact on the environment. During the preparation of molecular imprinted polymers, the functional monomers and template molecules are mainly combined through hydrogen bonds. The stronger the polarity of the solvent, the less conducive it is to form hydrogen bonds. Therefore, non-polar solvents such as acetonitrile or methanol are currently commonly used as solvents, but their disadvantages are high toxicity and environmental unfriendliness. The polar solvent ethanol is relatively green, but ethanol is unfavorable for many molecular imprintings (especially non-covalent imprintings) because it inhibits the formation of hydrogen bonds between the monomer and the template, which is also one of the difficulties faced by molecular imprinting technology.

[0007] At present, the preparation of imprinted photocatalysts mostly uses three-dimensional metal oxides as carriers, and there are few reports on two-dimensional molecular imprinted photocatalysts. Compared with traditional 3D nanoparticle photocatalysts, the ultra-thin structure of two-dimensional materials makes it easier to produce photocatalysts. − -h +Minimize the possibility of recombination. In addition, more "catalytically useful" defects and abundant coordinated unsaturated surface atoms in two-dimensional materials can provide more surface active sites, which is conducive to the transfer of charge from semiconductor to adsorbate, as well as the construction of imprinted sites on or near the surface active sites, accelerating the interfacial photocatalytic reaction. BiOCl is a two-dimensional photocatalytic material with a special layered structure. It has good photogenerated carrier separation efficiency, high chemical stability, adjustable physical and chemical properties, low cost, abundant resources, and environmental friendliness. It is widely used in environmental remediation and energy conversion. However, current research on BiOCl mainly focuses on the degradation of single pollutants, and lacks research on the selective degradation of target pollutants under complex matrix conditions. Summary of the invention

[0008] The technical problem solved by the present invention is to provide a method for preparing a two-dimensional bismuth-based surface molecular imprinting photocatalyst with simple process and good performance. The two-dimensional bismuth-based surface molecular imprinting photocatalyst prepared by the method has a strong ability to selectively adsorb the target substance venlafaxine in aqueous solution, and venlafaxine is preferentially and rapidly degraded under light conditions, and can be used for the selective photocatalytic removal of venlafaxine in actual water samples.

[0009] The present invention adopts the following technical scheme to solve the above technical problems: a method for preparing a two-dimensional bismuth-based surface molecular imprinted photocatalyst, characterized in that: a template molecule venlafaxine and a functional monomer 2-acrylamide-2-methylpropanesulfonic acid are dissolved in an ethanol solvent containing a carrier BiOCl nanosheet, prepolymerized at 20-40°C for 2-8 h, and then a crosslinking agent ethylene glycol dimethacrylate and an initiator azobisisobutyronitrile are added, and after ultrasonic and nitrogen protection, thermal polymerization is performed at 50-70°C for 20-30 h, and the two-dimensional bismuth-based surface molecular imprinted photocatalyst is obtained by elution and drying; The BiOCl nanosheets are synthesized by a hydrothermal method. The specific synthesis process is: dissolving bismuth nitrate pentahydrate into a mixed solvent of pure water and ethylene glycol with a volume ratio of 0.5-2:1, then dropping a saturated sodium chloride solution, stirring and mixing for 1-2 hours, placing in a polytetrafluoroethylene-lined high-pressure reactor, hydrothermally reacting at 130-180° C. for 3-6 hours, washing with water and ethanol several times, and drying to obtain the BiOCl nanosheets.

[0010] It is further defined that the molar ratio of the template molecule, the functional monomer, the cross-linking agent and the initiator is 1:2~6:1~16:1.

[0011] It is further defined that the elution process is specifically to use a mixture of methanol and acetic acid in a volume ratio of 9:1 for Soxhlet extraction for 48 hours.

[0012] The two-dimensional bismuth-based surface molecular imprinting photocatalyst of the present invention is used for the selective photocatalytic removal of venlafaxine in actual water samples.

[0013] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention uses a two-dimensional bismuth-based photocatalyst as a carrier to prepare a venlafaxine surface imprinted photocatalyst. By adjusting the thickness of the imprinted layer, the catalyst has the properties of fast adsorption rate, large adsorption capacity, strong anti-interference ability, fast degradation rate, etc.

[0014] 2. The present invention successfully prepared a two-dimensional bismuth-based surface molecular imprinting photocatalyst using ethanol as a preparation solvent, thereby reducing the secondary pollution to the environment caused by non-polar solvents such as acetonitrile and methanol.

[0015] 3. The present invention adopts methanol elution method to completely elute the template molecules, which is simple to operate and low in cost. The structure of the imprinted cavity is not affected after elution, the material selectivity is good, and the imprinting factor reaches 4.7. The reason is that the surface of the two-dimensional sheet structure is flat and has a large exposed surface, and there are many pores inside the three-dimensional structure, so the template molecules are not easy to be removed.

[0016] 4. BiOCl in the present invention is a two-dimensional photocatalyst with a unique layered structure and internal electric field effect, which is conducive to the effective separation and rapid transport of photogenerated carriers. Compared with the commonly used three-dimensional molecular imprinted photocatalytic matrix, BiOCl has a more positive valence band potential, which can activate molecular oxygen more continuously and effectively under light energy excitation, thereby achieving better degradation and removal of organic pollutants. In addition, more "catalytically useful" defects and abundant coordinated unsaturated surface atoms in the layered structure can provide more surface active sites, thereby promoting the transfer of charge from semiconductors to adsorbates and accelerating interfacial photocatalytic reactions. This is conducive to the rapid recognition, adsorption and efficient degradation of target pollutants by imprinted catalysts. The molecular imprinted polymer prepared by the present invention has an adsorption equilibrium time of 5 min for the target pollutant and a complete degradation time of 20 min, both of which are much lower than 1 h and 2 h in the literature (CN111234295B). BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the synthesis route of the carrier BiOCl and the imprinted photocatalyst MI-BiOCl in the present invention.

[0018] Figure 2 It is an electron microscope image of the carrier, imprinted photocatalyst and non-imprinted photocatalyst in the present invention.

[0019] Figure 3 It is the adsorption kinetics diagram of the imprinted photocatalyst and the non-imprinted photocatalyst of the present invention.

[0020] Figure 4 It is the adsorption isotherm diagram of the imprinted photocatalyst and the non-imprinted photocatalyst of the present invention.

[0021] Figure 5 The figure is a graph showing the change in the removal rate of venlafaxine over time by the imprinted photocatalyst and the photocatalyst carrier of the present invention in the presence of the interfering substance humic acid. DETAILED DESCRIPTION

[0022] The above contents of the present invention are further described in detail below through examples, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples, and all technologies implemented based on the above contents of the present invention belong to the scope of the present invention. Example 1

[0023] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0024] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.1 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 2

[0025] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0026] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.3 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 3

[0027] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0028] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.5 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the polymerization was thermally initiated at 60°C for 24 h to obtain the product, which was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 4

[0029] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0030] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.8 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 5

[0031] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0032] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.8 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 6

[0033] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0034] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 1.2 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 7

[0035] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0036] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 1.6 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 8

[0037] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0038] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.2 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.4 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 9

[0039] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0040] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.6 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.4 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 10

[0041] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0042] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.8 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Embodiment 11

[0043] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0044] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.8 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 12

[0045] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 8 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 180°C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0046] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.8 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Example 13

[0047] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 1 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 3 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0048] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.8 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Embodiment 14

[0049] Preparation of BiOCl nanosheets: 0.5 g of bismuth nitrate pentahydrate was dissolved in 55 mL of a mixed solvent of pure water and ethylene glycol in a volume ratio of 1:1, and then 1 mL of saturated sodium chloride solution was added dropwise. After stirring for 1 h, the mixture was placed in a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally reacted at 130 °C for 6 h. The mixture was washed several times with water and ethanol and dried to obtain BiOCl nanosheets.

[0050] Preparation of imprinted photocatalyst: Using 30 mL of ethanol as solvent, 0.10 g of the above-mentioned homemade BiOCl nanosheets (carrier), 0.1 mmol venlafaxine (template molecule) and 0.4 mmol 2-acrylamide-2-methylpropanesulfonic acid (functional monomer) were prepolymerized at 30°C for 4 h, and then 0.8 mmol cross-linking agent ethylene glycol dimethacrylate and 0.1 mmol initiator azobisisobutyronitrile were added. After ultrasonication and N2 filling, the product was thermally initiated and polymerized at 60°C for 24 h to obtain the product. The product was then extracted with a methanol / acetic acid mixture with a volume ratio of 9:1 for 48 h and then vacuum dried to obtain the imprinted photocatalyst. Embodiment 15

[0051] 20 mg of the imprinted photocatalyst (MI-BiOCl) and non-imprinted photocatalyst (NI-BiOCl) prepared in Example 1 were mixed with 50 mL and 20 mg L -1 The mixture was mixed with venlafaxine aqueous solution, and after oscillation at room temperature for a certain period of time (0-60 min), the supernatant was taken and the absorbance value at 225 nm was measured by UV spectrophotometer. Figure 3 shown. Example 16

[0052] 20 mg of the imprinted photocatalyst (MI-BiOCl) and the non-imprinted photocatalyst (NI-BiOCl) prepared in Example 1 were mixed with 50 mL of venlafaxine aqueous solution (0-80 mg L -1 ), after 1 h of oscillation adsorption at room temperature, the supernatant was taken and the absorbance at 225 nm was measured by UV spectrophotometer. Figure 4 shown. Embodiment 17

[0053] 20 mg of the imprinted photocatalyst (MI-BiOCl) and photocatalyst carrier (BiOCl) prepared in Example 1 were dispersed in 50 mL of venlafaxine (20 mg L -1 ) and humic acid (20 mg L -1 ) in a mixed aqueous solution, stirred for 30 min in the dark to ensure adsorption-desorption equilibrium, continued stirring under a 500 W xenon lamp, and measured the concentration of venlafaxine in the solution at regular intervals using high performance liquid chromatography. The results are shown in Figure 5 shown. Embodiment 18

[0054] The imprinted photocatalyst prepared in Example 1 was used for the photocatalytic degradation of venlafaxine in actual wastewater. The degradation results of the spiked experiment showed that the removal rate was close to 100%, and the residual concentration of venlafaxine after degradation was 12.5 ppb. This shows that the obtained imprinted photocatalyst has good practicality for the degradation of venlafaxine; after 4 cycles of use, the adsorption amount of venlafaxine by the imprinted photocatalyst still reached 15 mg g -1 , the total removal rate still reached more than 98%, indicating that the obtained imprinted polymer has excellent regeneration adsorption performance and stability.

[0055] The above embodiments describe the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the scope of the principles of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a two-dimensional bismuth-based surface molecularly imprinted photocatalyst, characterized in that The specific process is as follows: the template molecule venlafaxine and the functional monomer 2-acrylamide-2-methylpropanesulfonic acid are dissolved in an ethanol solvent containing the carrier BiOCl nanosheets, prepolymerized at 20-40°C for 2-8 h, and then the crosslinking agent ethylene glycol dimethacrylate and the initiator azobisisobutyronitrile are added. After ultrasonic and nitrogen protection, the two-dimensional bismuth-based surface molecularly imprinted photocatalyst is obtained by elution and drying. The BiOCl nanosheets are synthesized by a hydrothermal method. The specific synthesis process is: dissolving bismuth nitrate pentahydrate into a mixed solvent of pure water and ethylene glycol with a volume ratio of 0.5-2:1, then dropping a saturated sodium chloride solution, stirring and mixing for 1-2 hours, placing in a polytetrafluoroethylene-lined high-pressure reactor, hydrothermally reacting at 130-180° C. for 3-6 hours, washing with water and ethanol several times, and drying to obtain the BiOCl nanosheets.

2. The method for preparing the two-dimensional bismuth-based surface molecularly imprinted photocatalyst according to claim 1, characterized in that: The molar ratio of the template molecule, the functional monomer, the crosslinking agent and the initiator is 1:2-6:1-16:

1.

3. The method for preparing the two-dimensional bismuth-based surface molecularly imprinted photocatalyst according to claim 1, characterized in that: The elution process specifically includes Soxhlet extraction for 48 h using a mixture of methanol and acetic acid in a volume ratio of 9:

1.

4. The two-dimensional bismuth-based surface molecularly imprinted photocatalyst prepared by the method according to any one of claims 1 to 3 is used for the selective photocatalytic removal of venlafaxine in actual water samples.

Images