Preparation method of core-shell structure molecular imprinting type titanium dioxide material and application thereof in fluoxetine contaminated water remediation

Abstract

The application provides a preparation method of a core-shell structure molecular imprinting type titanium dioxide material and application of the material in fluoxetine contaminated water remediation, the inner core of the material is a nanometer sphere of anatase type titanium dioxide, and the outer layer is wrapped with a molecular imprinting titanium dioxide layer. The outer layer is constructed by using a molecular imprinting technology with fluoxetine as a template molecule to form specific adsorption sites for target molecules. The inner core is prepared by using a sol-gel method, tetrabutyl titanate is used as a precursor, and the nanometer sphere size is controlled by using n-valeric acid in a mixed solvent to obtain a uniform inner core. The outer layer loading is also based on a sol-gel process, the inner core, a template molecule fluoxetine and a titanium source are ultrasonically dispersed and stirred in a mixed solvent for reaction, and then the template molecule is removed. The prepared material can be used for removing fluoxetine in water: adsorption treatment is carried out in dark conditions, then the photocatalysis effect is utilized under light to degrade the psychoactive drug pollutants, and efficient removal is realized.

Description

Technical Field

[0001] This invention relates to the field of environmental functional materials technology, and particularly to a method for preparing a selective photocatalytic material and its application in the remediation of water bodies contaminated with the antidepressant fluoxetine. The selective photocatalytic material, through surface molecular imprinting modification technology, achieves efficient capture and removal of fluoxetine under complex aquatic environmental conditions, making it suitable for the remediation of complex aquatic environments. Background Technology

[0002] Fluoxetine (FXT) is one of the most commonly prescribed antidepressants, belonging to the broader class of selective serotonin reuptake inhibitors (SSRIs). Reports indicate that fluoxetine concentrations in municipal wastewater (MWW) and hospital wastewater (HWW) range from 31 ng / L to 500 ng / L. FXT exhibits high resistance to hydrolysis, photolysis, and microbial degradation, and is therefore considered a persistent pollutant that cannot be adequately removed by conventional wastewater treatment. In the effluent of traditional wastewater treatment plants, FXT removal rates range from 46% to 65%. Therefore, FXT is easily introduced into environmental water bodies and impacts aquatic life. According to some reports, its metabolite norfluoxetine has been found in the viscera (muscle, liver, and brain) of fish, adversely affecting their growth rate and reproduction (e.g., delayed sexual development or decreased estradiol levels), seriously threatening the balance of aquatic ecosystems. Therefore, it is essential to seek more effective and reliable materials for the efficient removal of FXT.

[0003] Titanium dioxide (TiO2) is considered a potential material for degrading emerging pollutants due to its diverse development potential. However, achieving selective removal of FXT pollutants in photocatalytic oxidation with TiO2 remains challenging because the active oxide species in the TiO2 photocatalytic process are mainly hydroxyl radicals, which can attack any organic matter subjected to photocatalytic treatment. To improve photocatalytic selectivity, this invention utilizes molecular imprinting technology as a TiO2 modification technique to overcome the limitation of photocatalysis due to its lack of specific recognition sites. Molecular imprinting is a promising customized approach that can obtain synthetic materials with specific recognition capabilities and selective adsorption of target molecules. The coupling of molecular imprinting with photocatalysis can improve the photocatalytic selectivity for template molecules, and the molecularly imprinted photocatalyst can selectively and preferentially destroy target pollutants, thereby producing satisfactory reductions in pollution levels and toxicity. Summary of the Invention

[0004] Technical problem to be solved: This invention addresses the problems of low removal efficiency and poor environmental adaptability of existing materials for fluoxetine, a pollutant caused by the psychotropic antidepressant drug. It provides a core-shell structured molecularly imprinted titanium dioxide material (MI-TiO2@TS) and its preparation method, which can be applied to the treatment of water bodies contaminated by the psychotropic antidepressant drug fluoxetine.

[0005] Technical solution: A core-shell structured molecularly imprinted titanium dioxide material, wherein the core-shell structured molecularly imprinted titanium dioxide material MI-TiO2@TS is composed of a molecularly imprinted titanium dioxide layer encapsulating anatase titanium dioxide nanospheres. The outer titanium dioxide layer is formed by molecular imprinting technology, using fluoxetine as a template molecule, to form an anatase titanium dioxide layer with specific molecularly imprinted adsorption sites and a thickness of 20~25 nm, which is wrapped on the surface of anatase titanium dioxide nanospheres with a diameter of 130~170 nm.

[0006] The preparation method of the above-mentioned core-shell structured molecularly imprinted titanium dioxide material includes the following steps:

[0007] S1. Core fabrication: Using tetrabutyl titanate as raw material, the diameter of the nanospheres was controlled by valeric acid through the sol-gel method. After vigorous stirring, the nanospheres were settled to form uniformly sized nanospheres. After centrifugation, freeze-drying, and calcination, titanium dioxide nanospheres as the core were obtained.

[0008] S2. Loading and encapsulation of molecularly imprinted titanium dioxide layers and removal of template molecules: Fluoxetine was used as the template molecule, tetrabutyl titanate was used as the titanium source, and the core titanium dioxide nanospheres were ultrasonically dispersed and mixed. The reaction was carried out by vigorous stirring using the sol-gel method, and the template molecules were removed by centrifugation, drying and calcination to obtain MI-TiO2@TS material.

[0009] Preferably, the sol-gel method in step S1 uses anhydrous ethanol, acetonitrile and deionized water in a volume ratio of 3:2:1 to prepare a solvent.

[0010] Preferably, the speed of vigorous stirring in step S1 is 300~700 rpm, the time is 10~12 min, and the settling time is 6~12 h.

[0011] Preferably, the centrifugation speed in step S1 is 8000~12000 rpm and the time is 10~12 min.

[0012] Preferably, the freeze-drying temperature in step S1 is -48 to -40°C, and the time is 6 to 24 hours.

[0013] Preferably, the calcination temperature in step S1 is 500~600℃; the time is 2~2.5h; and the heating rate is 2~3℃ / min.

[0014] Preferably, the molar ratio of the template molecule fluoxetine to the titanium source tetrabutyl titanate in step S2 is 1:2~6.

[0015] Preferably, the ultrasonic dispersion time in step S2 is 25-30 min, and the frequency is 45-50 kHz.

[0016] Preferably, the sol-gel method in step S2 uses a solvent prepared by mixing anhydrous ethanol, acetonitrile, deionized water and 28% concentrated ammonia in a volume ratio of 45:15:0.5:0.4~0.6.

[0017] Preferably, the speed of vigorous stirring in step S2 is 500~700 rpm, and the time is 1.5~2 hours.

[0018] Preferably, the centrifugation speed in step S2 is 10000~12000 rpm, and the time is 10~12 min.

[0019] Preferably, the drying temperature in step S2 is 60~80℃ and the time is 12~24h.

[0020] Preferably, the calcination temperature in step S2 is 500~600℃, the time is 2~2.5h, and the heating rate is 2~3℃ / min.

[0021] The above-mentioned MI-TiO2@TS material is used in a method for removing fluoxetine, a pollutant from water bodies, which is a psychotropic antidepressant. The method includes the following steps:

[0022] S11. Disperse MI-TiO2@TS material at a dosage of 0.2 g / L in the water to be treated with fluoxetine at a concentration of 100 μg / L to 10 mg / L, and mix and adsorb at 150 to 180 rpm for 0 to 60 min in a dark environment at 25 to 30 °C.

[0023] S12. The turbid suspension after shaking and mixing is placed under a 500W long-arc mercury lamp for 0-120 minutes of illumination to degrade fluoxetine, a psychotropic antidepressant pollutant, in the water.

[0024] Beneficial effects: The core-shell structured molecularly imprinted titanium dioxide material of this invention has the following advantages:

[0025] 1. Enhanced selective adsorption efficiency: Achieved selective adsorption of fluoxetine, a pollutant associated with the psychotropic antidepressant drug, and optimized both rapid kinetics and high adsorption capacity for specific pollutants, achieving strong chelation adsorption of FXT.

[0026] 2. Enhanced selective photocatalytic efficiency: The modified material can improve the selective photocatalytic ability of specific pollutants FXT, breaking through the non-selectivity bottleneck of traditional materials, and still exhibiting excellent performance in multiple cycles of application.

[0027] 3. Green Sustainability: By using low-cost raw materials and low-carbon preparation processes, carbon emissions during material production are significantly reduced. At the same time, by precisely controlling process parameters to control material structure, FXT provides a highly efficient, sustainable, and green solution for pollution control. Attached Figure Description

[0028] Figure 1 Scanning electron microscope image of MI-TiO2@TS material;

[0029] Figure 2 The FTIR plot of the material;

[0030] Figure 3 Scanning electron microscope image of TS material prepared using acetic acid regulation;

[0031] Figure 4 X-ray diffraction patterns of TS and TS@MI-TiO2 materials prepared by calcination at different temperatures;

[0032] Figure 5 The adsorption and treatment effect of TS@MI-TiO2 materials prepared under different molar ratios of fluoxetine template molecule and tetrabutyl titanate on fluoxetine pollutants in water.

[0033] Figure 6 Scanning electron microscope (SEM) image of MI-TiO2@TS material prepared by mixing anhydrous ethanol, acetonitrile, ultrapure water and 28% concentrated ammonia in a volume ratio of 45:15:0.5:0.4.

[0034] Figure 7 Scanning electron microscope (SEM) image of MI-TiO2@TS material prepared by mixing anhydrous ethanol, acetonitrile, ultrapure water and 28% concentrated ammonia in a volume ratio of 45:15:0.5:0.6.

[0035] Figure 8 The adsorption and treatment effect of MI-TiO2@TS material on fluoxetine pollutants of different concentrations in water.

[0036] Figure 9 The adsorption and treatment effects of MI-TiO2@TS and NI-TiO2@TS materials on fluoxetine pollutants in water bodies were evaluated.

[0037] Figure 10 The degradation effects of MI-TiO2@TS and NI-TiO2@TS materials on fluoxetine during the photocatalytic stage;

[0038] Figure 11 The adsorption and photocatalytic effects of the contaminant citalopram were compared between MI-TiO2@TS and NI-TiO2@TS materials.

[0039] Figure 12 The adsorption and photocatalytic effects of MI-TiO2@TS material and NI-TiO2@TS on water bodies containing both the target pollutant fluoxetine and the control pollutant citalopram were studied.

[0040] Figure 13 To improve the catalytic degradation cycle effect;

[0041] Figure 14 The adsorption and photolysis efficiencies of fluoxetine for MI-TiO2@TS, MI-TiO2@SiO2, and MI-TiO2@Fe2O3 are respectively. Detailed Implementation

[0042] The present invention will be further described below with reference to embodiments. These embodiments are illustrative of the present invention, but the present invention is not limited to these embodiments:

[0043] Example 1

[0044] This embodiment describes the preparation method of MI-TiO2@TS material and its selective photocatalytic effect on fluoxetine, a pollutant in water containing psychotropic antidepressants, including the following steps:

[0045] (1) Preparation of MI-TiO2@TS material

[0046] S1. Core fabrication: 0.296 ml tetrabutyl titanate and 0.435 ml valeric acid were mixed evenly and quickly poured into a mixed solution of 60 ml anhydrous ethanol, 40 ml acetonitrile and 19.6 ml deionized water. After vigorous stirring at 500 rpm for 10 min, the mixture was allowed to settle for 8 h. After centrifugation at 10000 rpm for 10 min, freeze-drying at -40℃ for 12 h, and calcining at 500℃ for 2 h in a muffle furnace at a heating rate of 2℃ / min, titanium dioxide nanospheres as the core were obtained.

[0047] S2. Loading and Removal of Template Molecularly Imprinted Titanium Dioxide Layers: 0.5 g of titanium dioxide nanospheres, 0.75 ml of tetrabutyl titanate, and 170 mg of fluoxetine were added to a mixed solution of 80 ml anhydrous ethanol and 40 ml acetonitrile and ultrasonically dispersed at 50 kHz for 30 min to form a suspension. Then, 0.5 ml of deionized water and 0.5 ml of 28% concentrated ammonia were added dropwise to the suspension, and the mixture was vigorously stirred at 500 rpm for 1.5 h. After centrifugation at 10000 rpm for 10 min and drying at 60 °C for 12 h, the material was calcined in a muffle furnace at a heating rate of 2 °C / min to 500 °C for 2 h to obtain MI-TiO2@TS material.

[0048] (2) Selective photocatalytic experiment of MI-TiO2@TS material on fluoxetine, a psychotropic drug pollutant in water:

[0049] S3. Adsorption of fluoxetine, a psychotropic drug pollutant in water, by MI-TiO2@TS material: A 30ml reaction system was established in a 50ml conical flask, containing 10mg / L fluoxetine and 0.2g / L MI-TiO2@TS material. The mixture was shaken and mixed at 150rpm for 30min in the dark at 25℃.

[0050] S4. Photocatalysis of fluoxetine, a psychotropic drug contaminant in water, by MI-TiO2@TS material: The shaken suspension was placed under a 500W long-arc mercury lamp with stirring at 500 rpm and irradiated for 30 min through a 365 nm wavelength filter. After filtration through a 0.22 μm filter membrane, the residual fluoxetine concentration was detected by HPLC and calculated based on the standard curve.

[0051] Example 2

[0052] The difference between this embodiment and Embodiment 1 is that: in step S1, the kernel is made by using acetic acid instead of valeric acid for control.

[0053] Example 3

[0054] The difference between this embodiment and embodiment 1 is that the core fabrication in step S1 involves heating the muffle furnace to 600°C.

[0055] Example 4

[0056] The difference between this embodiment and Embodiment 1 is that in step S2, the loading and encapsulation of the molecularly imprinted titanium dioxide layer and the removal of the template molecules are as follows: the molar ratio of the template molecule fluoxetine to the titanium source tetrabutyl titanate is 1:2.

[0057] Example 5

[0058] The difference between this embodiment and Embodiment 1 is that in step S2, the loading and encapsulation of the molecularly imprinted titanium dioxide layer and the removal of the template molecules are as follows: the molar ratio of the template molecule fluoxetine to the titanium source tetrabutyl titanate is 1:6.

[0059] Example 6

[0060] The difference between this embodiment and Embodiment 1 is that: in step S2, the loading and encapsulation of the molecularly imprinted titanium dioxide layer and the removal of the template molecules are carried out in the following volume ratios: anhydrous ethanol, acetonitrile, deionized water, and 28% concentrated ammonia water, which are 45:15:0.5:0.4 respectively.

[0061] Example 7

[0062] The difference between this embodiment and Embodiment 1 is that in step S2, the loading and encapsulation of the molecularly imprinted titanium dioxide layer and the removal of the template molecules are carried out in a volume ratio of anhydrous ethanol, acetonitrile, deionized water, and 28% concentrated ammonia, which are 45:15:0.5:0.6 respectively.

[0063] Example 8

[0064] The difference between this embodiment and Embodiment 1 is that: in step S2, the loading and encapsulation of the molecularly imprinted titanium dioxide layer and the removal of the template molecules are carried out by heating the muffle furnace to 600°C.

[0065] Example 9

[0066] The difference between this embodiment and Embodiment 1 is that: in step S3, the adsorption of fluoxetine, a psychotropic drug pollutant in water, by the MI-TiO2@TS material is as follows: the concentration of fluoxetine in the water to be treated is 100 μg / L.

[0067] Example 10

[0068] The difference between this embodiment and Embodiment 1 is that: in step S3, the adsorption of fluoxetine, a psychotropic drug pollutant in water, by the MI-TiO2@TS material takes 5 minutes.

[0069] Example 11

[0070] The difference between this embodiment and Embodiment 1 is that: in step S3, the adsorption of fluoxetine, a psychotropic drug pollutant in water, by the MI-TiO2@TS material takes 10 minutes.

[0071] Example 12

[0072] The difference between this embodiment and Embodiment 1 is that: in step S3, the adsorption of fluoxetine, a psychotropic drug pollutant in water, by the MI-TiO2@TS material takes 20 minutes.

[0073] Example 13

[0074] The difference between this embodiment and Embodiment 1 is that: in step S4, the photocatalysis of the MI-TiO2@TS material on the water pollutant fluoxetine is carried out by a light irradiation time of 10 min.

[0075] Example 14

[0076] The difference between this embodiment and Embodiment 1 is that: in step S4, the photocatalysis of the MI-TiO2@TS material on the water pollutant fluoxetine is carried out by a light irradiation time of 20 min.

[0077] Example 15

[0078] The difference between this embodiment and Embodiment 1 is that: in step S4, the photocatalysis of the MI-TiO2@TS material on the water pollutant fluoxetine is carried out by a light irradiation time of 30 min.

[0079] Example 16

[0080] The difference between this embodiment and Embodiment 1 is that: in step S4, the photocatalysis of the MI-TiO2@TS material on the water pollutant fluoxetine is carried out by a light irradiation time of 45 min.

[0081] Example 17

[0082] The difference between this embodiment and Embodiment 1 is that: in step S4, the photocatalysis of the MI-TiO2@TS material on the water pollutant fluoxetine is carried out by a light irradiation time of 60 min.

[0083] Comparative Example 1

[0084] The difference between this comparative example and Example 1 is that no template molecule, fluoxetine, was added during the preparation process, forming a non-molecularly imprinted material, NI-TiO2@TS, which was then applied to the selective photocatalysis of fluoxetine, a pollutant in water containing psychotropic antidepressants.

[0085] Comparative Example 2

[0086] The difference between this comparative example and Example 1 is that the pollutant in the water to be treated is citalopram, and the concentration of citalopram in this example is 10 mg / L.

[0087] Comparative Example 3

[0088] The difference between this comparative example and Comparative Example 1 is that the pollutant in the water to be treated is citalopram, and the concentration of citalopram in this example is 10 mg / L.

[0089] Comparative Example 4

[0090] The difference between this comparative example and Example 1 is that the water to be treated contains two different types of pollutants, fluoxetine and citalopram. In this example, the concentrations of fluoxetine and citalopram are 10 mg / L and 10 mg / L, respectively.

[0091] Comparative Example 5

[0092] The difference between this comparative example and Comparative Example 1 is that the water to be treated contains two different types of pollutants, fluoxetine and citalopram. In this example, the concentrations of fluoxetine and citalopram are 10 mg / L and 10 mg / L, respectively.

[0093] Comparative Example 6

[0094] The difference between this comparative example and Example 1 is that after each photocatalytic treatment, the material was centrifuged at 10,000 rpm for 10 min, dried at 60°C for 12 h, and then calcined in a muffle furnace at a heating rate of 2°C / min to 500°C for 2 h before a new photocatalytic experiment was conducted. This process was repeated 7 times.

[0095] Comparative Example 7

[0096] The difference between this comparative example and Example 1 is that the type of core is changed to spherical SiO2 particles of the same size, and it is applied to the selective photocatalysis of fluoxetine, a pollutant in water used as a psychotropic antidepressant.

[0097] Comparative Example 8

[0098] The difference between this comparative example and Example 1 is that the type of core is changed to spherical Fe2O3 particles of the same size, and it is applied to the selective photocatalysis of fluoxetine, a psychotropic antidepressant pollutant in water.

[0099] Comparative Example 9

[0100] The difference between this comparative example and Example 1 is that the photocatalysis of the MI-TiO2@TS material in step S4 on the waterborne psychotropic drug pollutant fluoxetine is carried out by an irradiation time of 80 min.

[0101] The various embodiments of the present invention are explained below with reference to the accompanying drawings:

[0102] The MI-TiO2@TS material prepared in Example 1 of this invention was subjected to scanning electron microscopy (SEM), as follows: Figure 1 As shown, the results indicate that the material has an average size of approximately 200 nm and exhibits uniformly distributed small particles and irregular voids, which is attributed to the predetermined selective recognition sites of FXT. Figure 4 As shown, the material underwent X-ray diffraction (XRD), and the results showed that the core-shell bilayer structure exhibited typical anatase TiO2 (JCPDS number 21-1272) characteristics, with 2θ = 25.3° (101), 37.0° (103), 37.8° (004), 38.5° (112), 48.0° (200), 54.0° (105), and 55.1° (211). Fourier transform infrared spectroscopy (FTIR) of the prepared material verified the construction of the template cavity during the material preparation process, as shown... Figure 2 As shown. Compared with NI-TiO2@TS, MI-TiO2@TS showed improvement at 1331 cm⁻¹. -1 1242 cm -1 and 1070 cm -1A peak at 2960 cm⁻¹ corresponds to the halogen stretching vibration (CF), the phenoxy stretching vibration (COC), and the CN bond stretching vibration, while a peak at 1518 cm⁻¹ corresponds to the alkane (CH) stretching vibration. -1 and 3014 cm -1 The peak at the specified location corresponds to the stretching of the aromatic ring (C=C, CH). Simultaneously, the frequencies observed in the FTIR spectrum of MI-TiO2@TS are the same as those obtained from the spectrum of fluoxetine, indicating that the construction of the molecular imprint has no negative impact on FXT. The FTIR spectrum of MI-TiO2@TS after template removal shows no corresponding characteristic peaks for FXT. These results indicate that the template agent was successfully removed by calcination. However, after the FXT template agent re-binded to the surface, the characteristic peaks of the FXT template molecules were observed again, indicating the specific adsorption of the target FXT molecules by the molecular imprint sites. These results confirm that clear molecular imprint sites on the surface can be repeatedly maintained by repeatedly removing the template, meaning that the molecular imprint of MI-TiO2@TS was successfully constructed.

[0103] Example 2 of this invention describes the control of core TiO2 preparation using acetic acid, such as... Figure 3 As shown in the figure, SEM analysis revealed that the core TiO2 material regulated by acetic acid had an irregular morphology and could not provide controllable basic material conditions for the encapsulation of the molecular imprinted layer.

[0104] In Embodiment 3 of this invention, the heating endpoint of the muffle furnace in the fabrication of the core TiO2 material is set to 600°C. Figure 4 As shown, after calcination at 600℃, the resulting TiO2 material exhibits a rutile crystal phase, which does not possess photocatalytic properties and cannot provide good photocatalytic ability for subsequent photocatalytic processes.

[0105] In Examples 1, 4, and 5 of this invention, the molar ratio of the template molecule fluoxetine to the titanium source tetrabutyl titanate was set to 1:4, 1:2, and 1:6, respectively. Figure 5 As shown, adsorption experiments conducted under dark conditions revealed that the saturated adsorption capacity reached its maximum when the molar ratio of the template molecule fluoxetine to the titanium source tetrabutyl titanate was 1:4. However, the saturated adsorption capacity was lower at a molar ratio of 1:6 than at 1:4, primarily due to insufficient imprinting sites during the molecular imprinting process. Furthermore, at a molar ratio of 1:2, closed molecular imprinting cavities were created, resulting in wasted imprinting sites; therefore, even with increased raw material usage, the saturated adsorption capacity did not increase accordingly. Therefore, a molar ratio of 1:4 for the template molecule fluoxetine and the titanium source tetrabutyl titanate was chosen during material preparation.

[0106] In Examples 1, 6, and 7 of this invention, the volume ratios of anhydrous ethanol, acetonitrile, ultrapure water, and 28% concentrated ammonia are v:v:v:v = 45:15:0.5:0.5 / 45:15:0.5:0.4 / 45:15:0.5:0.6, respectively. Figure 1 As shown in Figures 6 and 7, three processes occur during the nucleation and growth of the shell at different ammonia contents. When the volume of concentrated ammonia is relatively low (the volume ratio of anhydrous ethanol, acetonitrile, ultrapure water, and 28% concentrated ammonia is 45:15:0.5:0.4), the reaction rate is slow, resulting in more titanium dioxide oligomers that cannot effectively and completely coat the core. When the volume of concentrated ammonia is relatively high (the volume ratio of anhydrous ethanol, acetonitrile, ultrapure water, and 28% concentrated ammonia is 45:15:0.5:0.6), the reaction kinetics are strong, leading to a thicker shell and multiple cores encased in one shell. Therefore, in the material preparation process, the volume ratio of anhydrous ethanol, acetonitrile, ultrapure water, and 28% concentrated ammonia is chosen to be v:v:v:v = 45:15:0.5:0.5.

[0107] In Example 8 of this invention, the heating endpoint of the muffle furnace in the fabrication of the molecularly imprinted TiO2 layer material is set to 600°C. Figure 4 As shown, after calcination at 600℃, the molecularly imprinted TiO2 layer formed exhibits a rutile crystal phase, which does not possess photocatalytic properties and cannot provide good photocatalytic ability for subsequent photocatalytic processes.

[0108] Examples 1 and 9 of this invention respectively demonstrate the use of the prepared material to adsorb different concentrations of fluoxetine pollutants in water under dark conditions. Figure 8 As shown, when the concentration of fluoxetine pollutant in the water is 100 μg / L, its adsorption efficiency reaches approximately 90%, but its adsorption capacity is low, only reaching 0.44 mg / g, indicating that the material has not yet reached saturation adsorption during the adsorption process. In contrast, when the concentration of fluoxetine pollutant in the water is 10 mg / L, its adsorption capacity reaches 16.74 mg / g, while its adsorption efficiency is only 9%, indicating that the material can reach saturation adsorption under this condition, and fluoxetine pollutant residues still exist in the water. Therefore, a fluoxetine pollutant concentration of 10 mg / L in the water is selected as the preferred condition to better understand its photocatalytic performance.

[0109] Examples 1, 10, 11, and 12 of this invention respectively demonstrate the use of the prepared material to adsorb fluoxetine pollutants in water for different durations in a dark environment. Figure 9 As shown, the prepared MI-TiO2@TS material achieved saturated adsorption of fluoxetine pollutants within the first 10 minutes (Q0). MI，FXT= 16.74 mg / g), but its adsorption capacity still fluctuated after 10 min. In order to ensure that it can carry out good saturation adsorption during the adsorption process, the adsorption time of the prepared MI-TiO2@TS material was set to 30 min.

[0110] The adsorption and treatment effects of the MI-TiO2@TS material prepared in Example 1 and the NI-TiO2@TS material prepared in Comparative Example 1 on fluoxetine pollutants in water are as follows: Figure 9 As shown, MI-TiO2@TS achieved saturated adsorption of fluoxetine within 30 minutes, and the saturated adsorption capacity for fluoxetine was higher than that of NI-TiO2@TS (Q NI，FXT = 9.37 mg / g). The imprinting factor (IF) was used to evaluate the imprinting adsorption performance; a high imprinting factor (IF)... FXT =1.78) represents the excellent adsorption capacity of MI-TiO2@TS.

[0111] Examples 1, 12-17, and Comparative Example 9 of this invention respectively demonstrate how the prepared material was first used to adsorb fluoxetine pollutants in water under a dark environment, followed by photocatalytic treatment for different durations. Figure 10 As shown, the degradation rate of pollutants in MI-TiO2@TS continuously increased from 0 to 30 minutes, reaching a degradation rate of 99%. Continued photocatalytic degradation showed little change in the degradation rate, indicating that it had reached its maximum degradation rate.

[0112] The degradation effects of MI-TiO2@TS material prepared in Example 1 and NI-TiO2@TS prepared in Comparative Example 1 on fluoxetine during the photocatalytic stage are as follows: Figure 10 As shown, MI-TiO2@TS achieved a degradation rate of over 99% within 30 min, while NI-TiO2@TS achieved a degradation rate of over 99% within 60 min. MI-TiO2@TS exhibited a degradation rate more than twice that of NI-TiO2@TS, indicating that molecular imprinting can significantly improve the effective degradation of the target material.

[0113] Comparative Examples 2 and 3 of this invention demonstrate the adsorption and photocatalytic effects of MI-TiO2@TS and NI-TiO2@TS on the control pollutant citalopram. Figure 11 As shown, MI-TiO2@TS exhibits stronger degradation ability for FXT than CIT. The selective adsorption coefficient (SC) of MI-TiO2@TS for FXT on CIT in a single solution is 1.44, indicating good selectivity for FXT. Furthermore, during the photocatalytic process, the reaction rate of FXT is significantly higher than that of CIT for both MI-TiO2@TS and NI-TiO2@TS.

[0114] Comparative Examples 4 and 5 of this invention demonstrate the adsorption and photocatalytic effects of MI-TiO2@TS and NI-TiO2@TS materials on water bodies containing both the target pollutant fluoxetine and the control pollutant citalopram. Figure 12 As shown, in the composite solution of FXT and CIT, the imprinting factor (IF) of MI-TiO2@TS for FXT is 1.56, which is greater than that for CIT (IF=1.14). The selectivity coefficient of MI-TiO2@TS (SC=1.36) indicates that the MI-TiO2@TS imprinted cavity can selectively recognize and adsorb FXT.

[0115] Comparative Example 6 of this invention presents the performance stability results of the MI-TiO2@TS material, such as... Figure 13 As shown, after seven consecutive cycles, the photocatalytic efficiency of the MI-TiO2@TS material remained above 90% within the same time frame. This indicates that the MI-TiO2@TS material exhibits excellent performance stability.

[0116] The adsorption and photolysis efficiencies of fluoxetine in Comparative Example 7 of this invention, using MI-TiO2@TS, MI-TiO2@SiO2, and MI-TiO2@Fe2O3 respectively, are as follows: Figure 14 As shown, the adsorption rate of MI-TiO2@SiO2 in the dark was 33.45%, while that of MI-TiO2@Fe2O3 in the dark was 18.83%, significantly lower than that of MI-TiO2@TS. Meanwhile, under illumination, MI-TiO2@TS achieved a 99% degradation rate of fluoxetine after 60 minutes of illumination, while MI-TiO2@SiO2 and MI-TiO2@Fe2O3 were still not completely degraded after 120 minutes of illumination, with degradation rates of 73.87% and 58.76%, respectively. This indicates that compared to SiO2 and Fe2O3, the TS core contributes to the material's reactivity. This is mainly due to the near-perfect match between the core and the outer shell interface, resulting in a good band structure match and a low interfacial barrier. Photogenerated electrons and holes can migrate relatively freely throughout the material. In contrast, the SiO2 core cannot form an effective heterojunction with the TiO2 shell to separate charges; charge separation is not enhanced, therefore its photocatalytic performance is inferior to that of the TiO2 core. Furthermore, Fe2O3 and anatase TiO2 have significant differences in crystal structure and lattice constant. At their interface, numerous lattice defects, dangling bonds, and stresses are generated. These interface defects become highly efficient recombination centers for photogenerated electrons and holes, thereby reducing photocatalytic performance.

[0117] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A core-shell structured molecularly imprinted titanium dioxide material, characterized in that: The core-shell structured molecularly imprinted titanium dioxide material MI-TiO2@TS consists of a molecularly imprinted titanium dioxide layer encapsulating anatase titanium dioxide nanospheres. The outer titanium dioxide layer is formed by molecular imprinting technology, using fluoxetine as a template molecule, to form an anatase titanium dioxide layer with specific molecularly imprinted adsorption sites and a thickness of 20~25 nm, which is then wrapped on the surface of anatase titanium dioxide nanospheres with a diameter of 130~170 nm. The preparation method of the core-shell structured molecularly imprinted titanium dioxide material includes the following steps: S1. Core fabrication: Using tetrabutyl titanate as raw material, the diameter of the nanospheres was controlled by valeric acid through the sol-gel method. After vigorous stirring, the nanospheres were settled to form uniformly sized nanospheres. After centrifugation, freeze-drying, and calcination at 500℃, titanium dioxide nanospheres as the core were obtained. S2. Loading and encapsulation of molecularly imprinted titanium dioxide layers and removal of template molecules: Fluoxetine was used as the template molecule and tetrabutyl titanate as the titanium source. After ultrasonic dispersion and mixing with the core titanium dioxide nanospheres, the reaction was carried out by vigorous stirring using the sol-gel method. After centrifugation and drying, the template molecules were removed by calcination at 500℃ to obtain MI-TiO2@TS material. In step S2, the molar ratio of the template molecule fluoxetine to the titanium source tetrabutyl titanate is 1:

4.

2. The core-shell structured molecularly imprinted titanium dioxide material according to claim 1, characterized in that: The sol-gel method described in step S1 uses anhydrous ethanol, acetonitrile, and deionized water in a volume ratio of 3:2:1 to prepare a solvent.

3. The core-shell structured molecularly imprinted titanium dioxide material according to claim 1, characterized in that: The vigorous stirring speed described in step S1 is 300~700 rpm, the stirring time is 8~12 min, and the settling time is 6~12 h; and / or The centrifugation speed in step S1 is 8000~12000 rpm, and the centrifugation time is 10~12 min.

4. The core-shell structured molecularly imprinted titanium dioxide material according to claim 1, characterized in that: The freeze-drying process in step S1 is carried out at a temperature of -48 to -40°C for 6 to 24 hours; and / or The calcination time in step S1 is 2~2.5h; the heating rate is 2~3℃ / min.

5. The core-shell structured molecularly imprinted titanium dioxide material according to claim 1, characterized in that: The ultrasonic dispersion time in step S2 is 25~30 min, and the frequency is 45~50 kHz.

6. The core-shell structured molecularly imprinted titanium dioxide material according to claim 1, characterized in that: The vigorous stirring in step S2 is performed at a speed of 500-700 rpm for 1.5-2 hours; and / or In step S2, the centrifugation speed is 10000~12000 rpm and the time is 10~12 min.

7. The core-shell structured molecularly imprinted titanium dioxide material according to claim 1, characterized in that: The drying temperature in step S2 is 60~80℃, and the time is 12~24h; and / or The calcination time in step S2 is 2~2.5h, and the heating rate is 2~3℃ / min.

8. The method for applying the core-shell structured molecularly imprinted titanium dioxide material according to claim 1 to remove fluoxetine, a psychotropic antidepressant pollutant, from water, characterized in that... Includes the following steps: S11. Disperse MI-TiO2@TS material at a dosage of 0.2 g / L in the water to be treated with fluoxetine at a concentration of 100 μg / L to 10 mg / L, and mix and adsorb at 150 to 180 rpm for 0 to 60 min in a dark environment at 25 to 30 °C. S12. The turbid suspension after shaking and mixing is placed under a 500W long-arc mercury lamp for 0-120 minutes of illumination to degrade fluoxetine, a psychotropic antidepressant pollutant, in the water.

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