Application of ionic liquid functionalized copper compound nano-catalyst in degradation of antibiotics

Abstract

The invention discloses application of an ionic liquid functionalized copper compound nano-catalyst in degradation of antibiotics. A preparation method of the ionic liquid functionalized copper compound nano-catalyst comprises the following steps: (1) carrying out alkylation reaction on raw materials including 2-mercapto-1-methylimidazole and long-chain halogenated alkane; (2) carrying out ion exchange reaction on a product obtained in the step (1) and bis (trifluoromethanesulfonyl) lithium imide to obtain sulfydryl functionalized ionic liquid; and (3) fully mixing a copper acetate aqueous solution with the sulfydryl functionalized ionic liquid prepared in the step (2), separating to obtain an oil phase containing copper ions, and carrying out precipitation reaction on the oil phase and a strong alkali aqueous solution to obtain the ionic liquid functionalized copper compound nano-catalyst. The ionic liquid functionalized copper compound nano-catalyst disclosed by the invention is novel in structure, the dosage of the photocatalyst is lower when antibiotics are degraded, the degradation efficiency of 90% or above can be realized only in 5 minutes, and excellent catalytic activity and cycling stability are shown.

Description

Technical Field

[0001] This invention relates to the field of photocatalyst technology, and more particularly to the application of an ionic liquid functionalized copper compound nanocatalyst in the degradation of antibiotics. Background Technology

[0002] Antibiotics are widely used due to their significant bactericidal and anti-inflammatory effects. However, overuse and incomplete metabolism lead to their frequent detection in wastewater, and their persistent and highly toxic nature makes them typical emerging pollutants. These residues not only damage aquatic ecosystems but also accelerate the emergence and spread of drug-resistant strains, posing a threat to public health and socioeconomic security.

[0003] To address the challenges of antibiotic wastewater treatment, advanced oxidation technologies such as electrochemical oxidation, Fenton oxidation, and ozone oxidation have been extensively studied. However, these technologies generally suffer from drawbacks such as high energy consumption, demanding conditions, and byproduct generation. Photocatalysis, due to its high efficiency, environmental friendliness, and low cost, is considered one of the most promising degradation methods. Currently, various materials, including metal oxides and graphitic carbon nitride (g-C3N4), are widely used as photocatalysts for antibiotic removal. However, most pure photocatalysts exhibit photogenerated electrons (e... − ) — Hole (h + The rapid recombination of these materials leads to lower photocatalytic activity. To address this bottleneck, researchers have proposed strategies such as heterostructure construction, doping, and defect manipulation. Some new materials have shown good performance in antibiotic degradation, but problems such as high cost, limited resources, or demanding preparation conditions still exist.

[0004] In recent years, bismuth (Bi)-based and g-C3N4-based catalysts have attracted attention due to their excellent visible light response. For example, the MIL-101 / BiOBr heterojunction photo-Fenton catalyst can remove 94.3% of tetracycline hydrochloride within 60 minutes, and the CuO / g-C3N4 heterojunction system achieves 99.87% degradation within 10 minutes through PMS activation. However, Bi has extremely low abundance in the Earth's crust, making it difficult to support large-scale applications, while the high-temperature calcination process of CuO / g-C3N4 consumes too much energy, limiting its green sustainability. It is known that the high efficiency of CuO / g-C3N4 is mainly attributed to its special structure that promotes electron-hole pair separation, but how to maintain or even improve its performance while avoiding high-temperature calcination remains a challenge to be overcome. Therefore, the shortcomings of existing photocatalysts highlight the necessity of developing novel functionalized materials that are abundant in resources, low in energy consumption, and have excellent performance. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention discloses the application of an ionic liquid functionalized copper compound nanocatalyst in the degradation of antibiotics. This ionic liquid functionalized copper compound nanocatalyst has a novel structure and requires a lower dosage to degrade antibiotics, achieving a degradation efficiency of over 90% in just 5 minutes, demonstrating excellent catalytic activity and cycle stability.

[0006] The specific technical solution is as follows:

[0007] The application of an ionic liquid-functionalized copper compound nanocatalyst in the degradation of antibiotics, wherein the preparation method of the ionic liquid-functionalized copper compound nanocatalyst includes the following steps:

[0008] (1) The raw materials including 2-mercapto-1-methylimidazolium and long-chain haloalkanes are subjected to alkylation reaction;

[0009] (2) The product of step (1) is subjected to an ion exchange reaction with lithium bis(trifluoromethanesulfonyl)imide to obtain a thiol-functionalized ionic liquid.

[0010] (3) The copper acetate aqueous solution is thoroughly mixed with the thiol-functionalized ionic liquid prepared in step (2), and the oil phase containing copper ions is separated and then subjected to precipitation reaction with a strong alkaline aqueous solution to obtain the ionic liquid functionalized copper compound nanocatalyst.

[0011] The precipitation reaction is carried out at a temperature of 40~90℃.

[0012] This invention discloses the application of a novel ionic liquid functionalized copper compound nanocatalyst in the degradation of antibiotics. This ionic liquid functionalized copper compound nanocatalyst is synthesized in situ under mild conditions using a specific type of IL medium, avoiding the traditional high-temperature calcination process, reducing energy consumption and structural defects, and constructing a sustainable material preparation route.

[0013] Experiments revealed that this novel ionic liquid-functionalized copper compound nanocatalyst can rapidly and efficiently degrade antibiotics, especially TCH, at significantly lower dosages than existing photocatalyst / PMS systems, achieving a degradation efficiency of up to 93.6% in just 5 minutes. This is likely due to the π-conjugated electronic structure of a specific type of [MDTIM]NTf2 ionic liquid, which constructs a g-C3N4-like electronic environment on the CuO surface, effectively promoting the separation and migration of photogenerated carriers, thus enabling rapid and efficient degradation of TCH even under low-dose conditions.

[0014] Further mechanistic studies revealed that the active species playing a major role in antibiotic degradation in the ionic liquid-functionalized copper compound nanocatalyst / PMS system of this invention are h⁺, •O₂⁻, and ¹O₂. IL modification not only promotes photogenerated charge separation but also significantly enhances the generation of active species such as ¹O₂ and •O₂⁻, thereby endowing the material with more efficient photocatalytic degradation performance. Further density functional theory (DFT) and work function (Φ) calculations demonstrated that in the ionic liquid-functionalized copper compound nanocatalyst prepared in this invention, Cu and O not only exhibit significant orbital coupling with [MDTIM]NTf₂, but also show higher density of states in the valence band, reflecting their potential as electron donors. Simultaneously, the PDOS peak of [MDTIM]NTf₂ in IL is located in the conduction band, exhibiting excellent electron acceptor characteristics. This "donor-acceptor" synergistic effect constructs an efficient charge transport channel between the copper compound and IL, accelerating the separation of photogenerated electron-hole pairs (e⁻ / h⁺), thereby significantly improving photocatalytic performance.

[0015] Experiments also revealed that when the specific ionic liquid mentioned above was replaced with other common ionic liquids, such as 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine ([BMIM][NTf2]), the generation capacity of active species and the photocatalytic performance in the prepared catalyst-PMS composite system were significantly reduced. This result indicates that the structural characteristics of ionic liquids have a significant impact on catalytic activity. The sulfur functional groups and long-chain hydrophobic structures introduced into the ionic liquid used in this invention enhance its interaction with the copper compound surface and improve the reaction interface microenvironment, thereby achieving superior photocatalytic performance.

[0016] In step (1) of the present invention:

[0017] Preferably, the long-chain haloalkane has 10 to 15 carbon atoms; more preferably, it has 12 carbon atoms and the halogen is Cl or Br.

[0018] Preferably, 2-mercapto-1-methylimidazole and long-chain haloalkanes are added in equal molar amounts to facilitate complete reaction between the two.

[0019] Preferably, the alkylation reaction is carried out at a temperature of 60~80 °C.

[0020] In step (2) of the present invention:

[0021] Preferably, the product of step (1) is added in equimolar amounts with lithium bis(trifluoromethanesulfonyl)imide to allow for complete reaction between the two.

[0022] Preferably, the ion exchange reaction is carried out at room temperature;

[0023] Preferably, the crude product obtained after the ion exchange reaction is further subjected to washing and drying.

[0024] In step (3) of the present invention:

[0025] Preferably, the concentration of the copper acetate aqueous solution is 0.1~1.0 mol / L; more preferably, it is 0.2~0.4 mol / L.

[0026] Preferably, the volume ratio of copper acetate aqueous solution to thiol-functionalized ionic liquid is (2~8):1, more preferably (4~6):1, and even more preferably 5:1.

[0027] Preferably, the mixing is carried out at room temperature, and after thorough mixing, copper acetate is transferred from the aqueous phase to the oil phase.

[0028] Preferably, the strong alkaline aqueous solution is selected from one or more of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, and lithium hydroxide aqueous solution;

[0029] Preferably, the concentration of the strong alkali aqueous solution is 1.0~2.0 mol / L.

[0030] Preferably, the volume ratio of the oil phase containing copper ions to the strong alkaline aqueous solution is 1:(2~8); more preferably 1:(4~6); and even more preferably 1:5.

[0031] The ionic liquid functionalized copper compound nanocatalysts prepared after the above precipitation reaction include ionic liquid functionalized copper oxide (IL-CuO) and / or ionic liquid functionalized copper hydroxide (IL-Cu(OH)2).

[0032] Experiments revealed that the composition of the obtained product is closely related to the temperature of the precipitation reaction. When the reaction temperature is low, around 40°C, the product obtained is either IL-Cu(OH)2 or IL-Cu(OH)2 / CuO; when the reaction temperature is high, around 65-90°C, the product obtained is only IL-CuO.

[0033] Further testing of photocatalytic activity revealed that IL-CuO exhibited significantly better photocatalytic activity than IL-Cu(OH)2. Therefore, preferably, the precipitation reaction is carried out at a temperature of 65-90 °C; more preferably, the precipitation reaction is carried out at a temperature of 65 °C.

[0034] In this invention, the specific steps for applying the ionic liquid-functionalized copper compound nanocatalyst in the degradation of antibiotics are as follows:

[0035] A photocatalytic system comprising the aforementioned ionic liquid functionalized copper compound nanocatalyst and potassium persulfate (PMS) was added to wastewater containing antibiotics and subjected to catalytic degradation under visible light.

[0036] Preferably, the mass ratio of the ionic liquid functionalized copper compound nanocatalyst to potassium persulfate is 1:(1~15); more preferably 1:(2~12.5); even more preferably 1:(5~12.5); and most preferably 1:(5~10).

[0037] Preferably, the PMS is added in the form of an aqueous PMS solution, and the above mass ratio is based on the mass of PMS in the aqueous PMS solution.

[0038] Preferably, the concentration of the ionic liquid functionalized copper compound nanocatalyst added to the wastewater is not less than 0.02 g·L⁻¹; more preferably 0.02~0.1 g·L⁻¹; and even more preferably 0.02~0.04 g·L⁻¹.

[0039] Preferably, the antibiotic is selected from tetracyclines, specifically tetracycline hydrochloride, tetracycline, oxytetracycline, doxycycline hydrochloride, etc.

[0040] Preferably, the concentration of antibiotics in the wastewater is 1~50 mg·L⁻¹; more preferably 1~15 mg·L⁻¹.

[0041] Preferably, the pH value of the wastewater is 3.6 to 11.7; more preferably 5.5 to 10.1.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] This invention discloses a novel ionic liquid functionalized copper compound nanocatalyst. This ionic liquid functionalized copper compound nanocatalyst is synthesized in situ under mild conditions using a specific type of IL medium, avoiding the traditional high-temperature calcination process, reducing energy consumption and structural defects, and constructing a sustainable material preparation route.

[0044] When this ionic liquid-functionalized copper compound nanocatalyst is applied to the degradation of antibiotics, especially TCH, it can rapidly and efficiently degrade TCH with significantly lower dosage than existing photocatalyst / PMS systems, achieving a degradation efficiency of up to 93.6% in as little as 5 minutes. This ionic liquid-functionalized copper compound nanocatalyst also exhibits excellent cycling stability and durability; after 5 cycles, there is no significant structural change, and the degradation rate does not show a significant decrease. Attached Figure Description

[0045] Figure 1 The hydrogen nuclear magnetic resonance spectrum of the thiol-functionalized ionic liquid 1-methyl-2-dodecylthionazole bis(trifluoromethanesulfonyl)imine salt prepared in Example 1;

[0046] Figure 2The XRD patterns of the IL-functionalized copper compound nanoparticles prepared in Examples 1-9 are shown below.

[0047] Figure 3 High-resolution XPS spectrum of IL-functionalized copper compound nanoparticles prepared in Example 1;

[0048] Figure 4 High-resolution XPS spectrum of IL-functionalized copper compound nanoparticles prepared in Example 8;

[0049] Figure 5 FESEM image (a) and EDS elemental distribution map (b–g) of the IL-functionalized copper compound nanoparticles prepared in Example 1;

[0050] Figure 6 FESEM image (a) and EDS elemental distribution map (b–g) of the IL-functionalized copper compound nanoparticles prepared in Example 8;

[0051] Figure 7 FESEM image (a) and EDS elemental distribution map (b–g) of the IL-functionalized copper compound nanoparticles prepared in Example 7;

[0052] Figure 8 The nitrogen adsorption-desorption isotherms of the IL functionalized copper compound nanoparticles prepared in Examples 1-9 are shown below.

[0053] Figure 9 The UV-Vis spectra of the IL-functionalized copper compound nanoparticles prepared in Examples 1-3 are shown below.

[0054] Figure 10 The UV-Vis spectra of the IL-functionalized copper compound nanoparticles prepared in Examples 4-6 are shown below.

[0055] Figure 11 The UV-Vis spectra of the IL-functionalized copper compound nanoparticles prepared in Examples 7-9 are shown below.

[0056] Figure 12 The catalytic degradation curves of TCH by the IL-functionalized copper compound nanoparticles prepared in Examples 1-9 are shown.

[0057] Figure 13 Catalytic degradation curves of TCH by IL-functionalized copper compound nanoparticles prepared in Example 8 at different mass levels;

[0058] Figure 14 The catalytic degradation curves of TCH by IL-functionalized copper compound nanoparticles prepared in Example 8 and PMS aqueous solutions at different volumes are shown.

[0059] Figure 15 The catalytic degradation curves of TCH by the IL-functionalized copper compound nanoparticles prepared in Example 8 at different pH values ​​are shown.

[0060] Figure 16 The catalytic degradation curves of TCH by the IL-functionalized copper compound nanoparticles prepared in Example 8 at different wastewater concentrations are shown.

[0061] Figure 17 The catalytic degradation curve of TCH by the IL-functionalized copper compound nanoparticles prepared in Example 8 after 5 cycles is shown.

[0062] Figure 18 The figure shows the XRD pattern of the IL-functionalized copper compound nanoparticles prepared in Example 8 after 5 cycles. The figure also shows the XRD pattern of freshly synthesized IL-functionalized copper compound nanoparticles for comparison. Detailed Implementation

[0063] To make the objectives, features, and advantages of this invention more apparent, further embodiments are provided below to illustrate the invention in detail. These embodiments are for illustrative purposes only and should not be construed as limiting the scope of protection of this invention. Any non-essential improvements and adjustments made by those skilled in the art based on the principles described herein are within the scope of protection of this invention.

[0064] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0065] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0066] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0067] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. Where the terms "first," "second," etc., are used throughout the text, they are used only to distinguish similar objects and should not be construed as indicating or implying their relative importance, order of precedence, or implicitly specifying the number of technical features indicated. It should be understood that the data in the descriptions of "first," "second," etc., can be interchanged where appropriate.

[0068] The raw materials used in this invention are described below:

[0069] 2-Mercapto-1-methylimidazolium (MMI, 98%), 1-bromododecane (98%), sodium thiosulfate (Na₂S₂O₃, 99%), potassium peroxymonosulfate (PMS, KHSO₅), lithium bis(trifluoromethanesulfonyl)imide (LiNTf₂, 99.9%), and furfuryl alcohol (FA, 98%) were supplied by Maclean's Reagents, Inc. (Shanghai, China). Copper acetate monohydrate (Cu(Ac)₂·H₂O, 99%) was purchased from Tianjin Fengchuan Chemical Reagent Technology Co., Ltd., 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt was purchased from Aladdin Reagents, Inc. (Shanghai, China), and tetracycline hydrochloride (TCH, 99%) was purchased from Aladdin Reagents, Inc. (Shanghai, China). Unless otherwise specified, all other reagents were of analytical grade.

[0070] Example 1

[0071] (1) Synthesis of thiol-functionalized IL

[0072] Using equimolar amounts of MMI and 1-bromododecane as starting materials, the reaction was stirred at 70 °C for 8 h. Subsequently, equimolar amounts of LiNTf2 were added to generate an oil phase. After multiple water washings, the oil phase was dried at 70 °C for 12 h to finally obtain a light pink liquid thiol-functionalized ionic liquid, 1-methyl-2-dodecylthionazole bis(trifluoromethanesulfonyl)imine salt ([MDTIM]NTf2), with a yield of 91.6%. The synthetic route of the ionic liquid [MDTIM]NTf2 is shown in the following formula:

[0073]

[0074] The chemical structure of the ionic liquid [MDTIM]NTf2 was characterized by ¹H NMR (Ascend 400, 400 MHz, solvent: DMSO-d6, Bruker Biospin, Rheinstetten, Germany). The ¹H NMR spectrum is shown in […]. Figure 1Chemical shifts (δ, ppm): 0.840–0.874 (t, 3H), 1.240–1.354 (m, 18H), 1.497–1.570 (m, 2H), 2.508 (residual solvent signal), 3.119–3.155 (t, 2H), 3.803 (s, 3H), 7.739–7.744 (d, 1H), 7.793–7.798 (d, 1H).

[0075] (2) Preparation of IL-functionalized copper compound nanoparticles

[0076] 15 mL of a 0.2 mol·L⁻¹ Cu(Ac)₂ aqueous solution was mixed with 3 mL of the [MDTIM]NTf₂ prepared in step (1) and stirred at room temperature for 1 h to transfer Cu(Ac)₂ from the aqueous phase to the [MDTIM]NTf₂ phase. After removing the aqueous phase, 3 mL of the copper-containing [MDTIM]NTf₂ phase was stirred with 15 mL of a 1.0 mol·L⁻¹ NaOH aqueous solution at 40 °C for 1 h to generate a precipitate. The precipitate was washed with deionized water and anhydrous ethanol, and then dried at 70 °C for later use.

[0077] XRD characterization revealed that the product prepared in this example was IL-functionalized copper hydroxide nanoparticles, denoted as IL-Cu(OH)2-1. The XRD results are as follows: Figure 2 .

[0078] Example 2

[0079] The preparation process is basically the same as in Example 1, except for step (2):

[0080] Replace the concentration of the NaOH aqueous solution with 1.5 mol·L⁻¹ and the reaction temperature with 65 ℃.

[0081] XRD characterization revealed that the product prepared in this embodiment was IL-functionalized copper oxide nanoparticles, denoted as IL-CuO-2. The XRD results are as follows: Figure 2 .

[0082] Example 3

[0083] The preparation process is basically the same as in Example 1, except for step (2):

[0084] Replace the concentration of the NaOH aqueous solution with 2.0 mol·L⁻¹ and the reaction temperature with 90 ℃.

[0085] XRD characterization revealed that the product prepared in this example was IL-functionalized copper oxide nanoparticles, denoted as IL-CuO-3. The XRD results are as follows: Figure 2 .

[0086] Example 4

[0087] The preparation process is basically the same as in Example 1, except for step (2):

[0088] Replace the concentration of Cu(Ac)2 aqueous solution with 0.3 mol·L⁻¹ and the concentration of NaOH aqueous solution with 1.5 mol·L⁻¹.

[0089] XRD characterization revealed that the product prepared in this example was IL-functionalized copper hydroxide nanoparticles, denoted as IL-Cu(OH)2-4. The XRD results are as follows: Figure 2 .

[0090] Example 5

[0091] The preparation process is basically the same as in Example 4, except for step (2):

[0092] Replace the concentration of the NaOH aqueous solution with 2.0 mol·L⁻¹ and the reaction temperature with 65 ℃.

[0093] XRD characterization revealed that the product prepared in this embodiment was IL-functionalized copper oxide nanoparticles, denoted as IL-CuO-5. The XRD results are as follows: Figure 2 .

[0094] Example 6

[0095] The preparation process is basically the same as in Example 4, except for step (2):

[0096] Replace the concentration of the NaOH aqueous solution with 1.0 mol·L⁻¹ and the reaction temperature with 90 ℃.

[0097] XRD characterization revealed that the product prepared in this embodiment was IL-functionalized copper oxide nanoparticles, denoted as IL-CuO-6. The XRD results are as follows: Figure 2 .

[0098] Example 7

[0099] The preparation process is basically the same as in Example 4, except for step (2):

[0100] Replace the concentration of Cu(Ac)2 aqueous solution with 0.4 mol·L⁻¹ and the concentration of NaOH aqueous solution with 2.0 mol·L⁻¹.

[0101] XRD characterization revealed that the product prepared in this example was IL-functionalized copper hydroxide / copper oxide composite nanoparticles, denoted as IL-Cu(OH)2 / CuO-7. The XRD results are as follows: Figure 2 .

[0102] Example 8

[0103] The preparation process is basically the same as in Example 7, except for step (2):

[0104] Replace the concentration of the NaOH aqueous solution with 1.0 mol·L⁻¹ and the reaction temperature with 65 ℃.

[0105] XRD characterization revealed that the product prepared in this embodiment was IL-functionalized copper oxide nanoparticles, denoted as IL-CuO-8. The XRD results are as follows: Figure 2 .

[0106] Example 9

[0107] The preparation process is basically the same as in Example 7, except for step (2):

[0108] Replace the concentration of the NaOH aqueous solution with 1.5 mol·L⁻¹ and the reaction temperature with 90 ℃.

[0109] XRD characterization revealed that the product prepared in this embodiment was IL-functionalized copper oxide nanoparticles, denoted as IL-CuO-9. The XRD results are as follows: Figure 2 .

[0110] observe Figure 2 XRD results showed that the product synthesized at 40 °C was Cu(OH)₂ (JCPDS No. 72-0140, such as IL-Cu(OH)₂-1 and IL-Cu(OH)₂-4), or a mixture of Cu(OH)₂ and CuO (IL-Cu(OH)₂ / CuO-7); while the samples prepared at 65 °C and 90 °C were monoclinic CuO (JCPDS No. 48-1548). According to the formula... and The calculated grain size (D) and lattice strain (ε) are close to those reported in the literature, indicating that the structure of the synthesized sample is reliable.

[0111] Figure 3The high-resolution XPS spectrum of the IL-Cu(OH)2-1 material prepared in Example 1 is shown. XPS characterization revealed Cu 2p peaks at 933.6–934.8 eV and 953.6–954.6 eV, corresponding to Cu 2p3 / 2 and Cu 2p1 / 2 peaks, respectively, accompanied by typical satellite peaks. The O 1s spectrum showed O=S=O signals from the IL anion NTf2⁻, hydroxyl oxygen / adsorbed water signals from the Cu(OH)2 sample, and oxygen signals from the CuO lattice. The C 1s and N 1s peaks further confirmed the presence of C–F, C=N, C–N, and both cation and anion nitrogen in the IL. The F 1s and S 2p spectra showed C–F and C=S / O=S=O signals, respectively. The N, F, and S peaks were relatively weak. Combined with EDS quantitative results, this indicates that only trace amounts of IL (0.15–0.38 wt%) were present on the surface.

[0112] Figure 4 The high-resolution XPS spectra of the IL-CuO-8 material prepared in Example 8 are shown. The Cu 2p spectrum shows peaks at 933.7 eV and 953.9 eV corresponding to Cu 2p3 / 2 and Cu 2p1 / 2 peaks, respectively, accompanied by distinct satellite peaks, indicating that the sample is predominantly in the Cu²⁺ CuO state. The O 1s spectrum can be decomposed into 529.7 eV (CuO lattice oxygen), 531.3 eV (S=O bond in the IL anion NTf2⁻), and 532.7 eV (hydroxyl oxygen / adsorbed water). The C 1s and N 1s spectra further confirm the presence of C–N and C=N in the IL cation and C–F and nitrogen environments in NTf2⁻. The F 1s and S 2p spectra appear at 688.5 eV and 163.2 eV, respectively, corresponding to the C–F and S=O signals of NTf2⁻. The weak intensities of N, F, and S peaks indicate that the sample is composed of CuO with trace amounts of IL surface modification.

[0113] Figure 5 The FESEM image (a) and EDS elemental distribution maps (b–g) of the IL-Cu(OH)2-1 nanoparticles prepared in Example 1 show that the sample exhibits a needle-like morphology. The EDS elemental distribution mapping indicates that Cu, O, C, N, F, and S are uniformly distributed, further proving the successful IL modification. The morphology of the product prepared in Example 4 is similar.

[0114] Figure 6 FESEM images (a) and EDS elemental distribution maps (b–g) of the IL-CuO-8 nanoparticles prepared in Example 8 show that the sample exhibits a flower-like nanosheet structure. The EDS elemental distribution mapping indicates that Cu, O, C, N, F, and S are uniformly distributed, further proving the successful IL modification. The morphology of the products prepared in Examples 2, 3, 5, 6, and 9 is similar.

[0115] Figure 7The FESEM image (a) and EDS elemental distribution map (b–g) of the IL-Cu(OH)2 / CuO-7 nanoparticles prepared in Example 7 show that there are two morphologies in the sample: needle-like and flower-like nanosheets. The EDS elemental distribution map shows that Cu, O, C, N, F and S are uniformly distributed, which further proves that the IL modification was successful.

[0116] Figure 8 The figure shows the nitrogen adsorption-desorption isotherms of the IL-functionalized copper compound nanoparticles prepared in Examples 1-9, respectively. The figure indicates that all samples are type IV, accompanied by an H3-type hysteresis loop, confirming their slit-like mesoporous characteristics. Table 1 below provides the specific surface area, pore size, pore volume, and sulfur content of each product.

[0117] Table 1

[0118]

[0119] Figures 9-11 The UV-Vis spectra of the IL-functionalized copper compound nanoparticles prepared in Examples 1-9 are given respectively. The UV-Vis spectra show that the IL-Cu(OH)2 sample has an absorption peak at about 670 nm, while IL-CuO has strong absorption in the entire visible light range. Further analysis using the Tauc equation (… According to calculations, the band gap of the IL-Cu(OH)2 sample is 3.1~3.4 eV, while the band gap of IL-CuO drops to 1.9~2.1 eV, indicating that the CuO material modified by IL has superior visible light response characteristics.

[0120] Comparative Example 1

[0121] The preparation process is the same as in Example 8, except that:

[0122] In step (2), [MDTIM]NTf2 is replaced with an equal volume of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ([BMIM][NTf2]). The resulting product is denoted as BMIM-CuO.

[0123] Photocatalytic performance evaluation:

[0124] Application Examples 1-9

[0125] Using the IL-functionalized copper compound nanoparticles prepared in each embodiment as photocatalysts, the catalytic performance of the photocatalysts for the degradation of tetracycline hydrochloride was evaluated by activating PMS under natural sunlight. The specific steps are as follows:

[0126] 50 mL of TCH aqueous solution (pH 7.0, concentration 10 mg·L⁻¹) and 2.0 mg of photocatalyst were stirred at 25 °C in the dark for 20 min to reach adsorption equilibrium. Then, 1.0 mL of PMS aqueous solution (20 g·L⁻¹) was added to initiate the degradation reaction under natural sunlight. The concentration of TCH in the aqueous phase was measured using a TU-1810 UV-Vis spectrophotometer (Purkinje General Instrument Co., Ltd., Beijing, China) at a wavelength of 363 nm. The TCH degradation efficiency (DE) was calculated using the following formula:

[0127]

[0128] Among them, C0 and C t The values ​​represent the initial TCH concentration and the TCH concentration at time t, respectively. The pH of the solution was adjusted using 1.0 mol·L⁻¹ HCl or 1.0 mol·L⁻¹ NaOH solution. All experiments were performed in duplicate, and results are expressed as mean ± standard deviation (SD).

[0129] Figure 12 The catalytic degradation curves of TCH by IL-functionalized copper compound nanoparticles prepared in each example are shown. Comparison revealed that all catalysts achieved high degradation efficiency in a short time, but significant differences in activity were observed between different samples. IL-CuO-8 exhibited the best catalytic activity, reaching a degradation rate of 92.6% in 5 minutes and further increasing to 95.6% in 30 minutes. IL-CuO-5 and IL-CuO-2 also showed relatively fast degradation rates and high final efficiencies. In contrast, IL-Cu(OH)2-1 and IL-Cu(OH)2-4, containing a portion of Cu(OH)2, had lower initial reaction rates, with degradation efficiencies slightly lower than the CuO host material within 20 minutes, but still reached approximately 90% in 30 minutes. The mixed-phase sample IL-Cu(OH)2 / CuO-7 showed performance between the two. These results indicate that the CuO host structure and appropriate IL modification can significantly enhance the rapid degradation ability of TCH, while the presence of Cu(OH)2 reduces the initial reaction kinetics to some extent. Table 2 below also shows the TCH degradation efficiency of different catalysts at different times.

[0130] Table 2

[0131]

[0132] Using the IL-functionalized copper compound nanoparticles prepared in Example 8 as a photocatalyst, the effects of photocatalyst dosage, PMS dosage, aqueous solution pH, and TCH concentration on TCH degradation were further evaluated.

[0133] Comparative Application Example 1

[0134] The process was basically the same as in Application Example 8, except that the catalyst was replaced with an equal mass of the catalyst prepared in Comparative Example 1.

[0135] The results showed that, within the same treatment time, the photocatalytic activity of the catalyst prepared in the comparative ratio and the photocatalytic system composed of PMS was significantly reduced, and the TCH degradation efficiency was less than 70% after 30 min of treatment.

[0136] The above results indicate that not all imidazole-based ionic liquid modifications can significantly improve the photocatalytic performance of copper oxide nanoparticles; the structural characteristics of the ionic liquid have a significant impact on catalytic activity. The sulfur functional groups and long-chain hydrophobic structures introduced into the ionic liquid used in this invention enhance its interaction with the copper compound surface and improve the reaction interface microenvironment, thereby achieving superior photocatalytic performance.

[0137] Application Examples 10-13

[0138] The process was essentially the same as in Application Example 8, except that the mass of the photocatalyst (IL-CuO-8) was successively replaced with 0 mg (0.0 g L). -1 ), 1.0 mg (0.02 g L) -1 ), 3.0 mg (0.06 g L) -1 ), 5.0 mg (0.1 g L) -1 ).

[0139] Figure 13 To observe the catalytic degradation curves of TCH by the IL-functionalized copper compound nanoparticles prepared in Example 8 at different mass levels in Examples 8, 10-13, it was found that the degradation efficiency of TCH increased with the increase of IL-CuO-8 dosage. Considering that a degradation efficiency of 92.6% could be achieved within 5 min at 0.04 g·L⁻¹, and that further increasing the dosage would have limited contribution to improving the degradation effect, 0.04 g·L⁻¹ was determined to be the optimal dosage of IL-CuO-8.

[0140] Application Examples 14-18

[0141] The process was essentially the same as in Application Example 8, except that the volume of the PMS aqueous solution was successively replaced with 0 mL (0.0 g L). -1 ), 0.2 mL (0.08 g L) -1 ), 0.5 mL (0.2 g L) -1 ), 0.75 mL (0.3 g L) -1 ) and 1.25 mL (0.5 g L -1 ).

[0142] Figure 14 To illustrate the catalytic degradation curves of TCH using the IL-functionalized copper compound nanoparticles prepared in Example 8 (14-18) and PMS aqueous solutions at different volumes, it was observed that the degradation efficiency of TCH significantly increased with increasing PMS dosage. At 0.0 g·L⁻¹, almost no degradation occurred; when PMS was increased to 0.08–0.2 g·L⁻¹, the degradation rate accelerated significantly; the highest degradation efficiency was achieved at 0.3–0.4 g·L⁻¹, with a degradation rate of approximately 97% after 30 minutes. Further increases to 0.5 g·L⁻¹ showed limited improvement, indicating that 0.3–0.4 g·L⁻¹ is the optimal PMS dosage range.

[0143] Application Examples 19-23

[0144] The process was basically the same as in Application Example 8, except that the pH values ​​of the TCH aqueous solution were replaced sequentially with 3.6, 5.5, 8.0, 10.1 and 11.7.

[0145] Figure 15 The catalytic degradation curves of TCH by the IL-functionalized copper compound nanoparticles prepared in Example 8 (Examples 8, 19-23) at different pH values ​​were observed. It was found that the degradation efficiency of TCH remained high under pH conditions ranging from 5.5 to 10.1, indicating that the catalytic system has stable reaction performance in neutral and weakly acidic / weakly alkaline environments. At pH 3.6 and pH 11.7, the initial reaction rate decreased, especially at pH 11.7, where the degradation efficiency was only 56.2% after 5 minutes. However, as the reaction proceeded to 30 minutes, the degradation rate still increased to 83.2%.

[0146] Application Examples 24-25

[0147] The process was basically the same as in Application Example 8, except that the concentration of the TCH aqueous solution was replaced with 5 mg·L⁻¹ and 15 mg·L⁻¹ in sequence.

[0148] Figure 16 The catalytic degradation curves of TCH by the IL-functionalized copper compound nanoparticles prepared in Example 8 (using Examples 8, 24-25) at different wastewater concentrations were observed. It was found that IL-CuO-8 exhibited high catalytic degradation ability at initial TCH concentrations of 5 mg·L⁻¹, 10 mg·L⁻¹, and 15 mg·L⁻¹, with degradation rates exceeding 90% after 30 min. The degradation rate decreased slightly with increasing TCH concentration, with the highest efficiency at 5 mg·L⁻¹. While degradation was slightly slower at 15 mg·L⁻¹ in the early stage of the reaction (≤10 min), it still reached 91.3% after 30 min, indicating that the catalyst has good applicability in wastewater of different concentrations.

[0149] Table 3 below further compares the TCH degradation performance data of different photocatalyst / PMS systems, including nitrogen-doped carbon quantum dot modified oxygen-vacancy CuFe2O4 / nitrogen-vacancy g-C3N4 composite material (N-CQDs / CFOᵥ / NᵥCN), N, S, B triple-doped biochar (NSB-BC), lanthanum copper Rudelson-Bopper perovskite oxide (La2CuO4), CuO 1-x The study included various nanomaterials such as SiO2, cerium-doped CuCoO2 nanosheets (Ce-CuCoO2 NSs), oxygen-vacancy-rich CuO (OVs-CuO), carbonyl-modified g-C3N4 (CO-C3N4), NiFe2O4 / g-C3N4, and two-dimensional / three-dimensional biochar-modified g-C3N4 (2D / 3D BC-C3N4). Comparative analysis revealed that the IL-CuO-8 material constructed in this invention achieves higher degradation efficiency with significantly lower dosage, fully demonstrating its green, efficient, and application advantages.

[0150] Table 3

[0151]

[0152] Application Example 26

[0153] The reusability of IL-CuO-8 prepared in Example 8 was evaluated through continuous cycling experiments. The degradation process was exactly the same as in Application Example 8. After 5 cycles, the TCH degradation efficiency did not show a significant decrease, such as... Figure 17 As shown, this demonstrates that IL-CuO-8 exhibits excellent reusability. Furthermore, the recovered IL-CuO-8 was characterized by XRD. Figure 18 The results showed that the structure of IL-CuO-8 did not change significantly after five cycles of experiments, indicating that it has good stability and durability.

[0154] The above description is only a few specific embodiments of the present invention. It should be noted that many variations and improvements can be made by those skilled in the art. All variations or improvements that do not exceed the scope of the claims should be considered as the protection scope of the present invention.

Claims

1. The application of an ionic liquid-functionalized copper compound nanocatalyst in the degradation of antibiotics, characterized in that, The preparation method of the ionic liquid functionalized copper compound nanocatalyst includes the following steps: (1) The raw materials including 2-mercapto-1-methylimidazolium and long-chain haloalkanes are subjected to alkylation reaction; (2) The product of step (1) is subjected to an ion exchange reaction with lithium bis(trifluoromethanesulfonyl)imide to obtain a thiol-functionalized ionic liquid. (3) The copper acetate aqueous solution is thoroughly mixed with the thiol-functionalized ionic liquid prepared in step (2), and the oil phase containing copper ions is separated and then subjected to precipitation reaction with a strong alkaline aqueous solution to obtain the ionic liquid functionalized copper compound nanocatalyst. The precipitation reaction is carried out at a temperature of 40~90℃.

2. The application of the ionic liquid functionalized copper compound nanocatalyst according to claim 1 in the degradation of antibiotics, characterized in that, In step (1): The long-chain haloalkane has 10 to 15 carbon atoms; Equal molar amounts of 2-mercapto-1-methylimidazole and long-chain haloalkanes were added; The alkylation reaction is carried out at a temperature of 60~80℃.

3. The application of the ionic liquid functionalized copper compound nanocatalyst according to claim 1 in the degradation of antibiotics, characterized in that, In step (2): The product of step (1) was added in equimolar amounts with lithium bis(trifluoromethanesulfonyl)imide; The ion exchange reaction is carried out at room temperature.

4. The application of the ionic liquid functionalized copper compound nanocatalyst according to claim 1 in the degradation of antibiotics, characterized in that, In step (3): The concentration of the copper acetate aqueous solution is 0.1~1.0 mol / L; The volume ratio of copper acetate aqueous solution to thiol-functionalized ionic liquid is (2~8):

1.

5. The application of the ionic liquid functionalized copper compound nanocatalyst according to claim 1 in the degradation of antibiotics, characterized in that, In step (3): The strong alkaline aqueous solution is selected from one or more of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, and lithium hydroxide aqueous solution; The concentration of the strong alkali aqueous solution is 1.0~2.0 mol / L; The volume ratio of the oil phase containing copper ions to the strong alkaline aqueous solution is 1:(2~8).

6. The application of the ionic liquid functionalized copper compound nanocatalyst according to claim 1 in the degradation of antibiotics, characterized in that, In step (3), the precipitation reaction is carried out at a temperature of 65~90℃.

7. The application of the ionic liquid functionalized copper compound nanocatalyst according to claim 1 in the degradation of antibiotics, characterized in that, In step (3), the precipitation reaction is carried out at a temperature of 65°C.

8. The application of the ionic liquid functionalized copper compound nanocatalyst according to claim 1 in the degradation of antibiotics, characterized in that, The specific steps are as follows: A photocatalytic system comprising the aforementioned ionic liquid functionalized copper compound nanocatalyst and potassium persulfate was added to wastewater containing antibiotics, and catalytic degradation was carried out under visible light.

9. The application of the ionic liquid functionalized copper compound nanocatalyst according to claim 8 in the degradation of antibiotics, characterized in that: The mass ratio of ionic liquid-functionalized copper compound nanocatalyst to potassium persulfate is 1:(1~15). The concentration of the ionic liquid functionalized copper compound nanocatalyst added to the wastewater is not less than 0.02 g·L⁻¹.

10. The application of the ionic liquid functionalized copper compound nanocatalyst according to claim 8 in the degradation of antibiotics, characterized in that: The antibiotic is selected from tetracyclines; The concentration of antibiotics in the wastewater is 1~50 mg·L⁻¹.

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