A Cu / NH2-MIL-125(Ti) photocatalyst, its preparation method and application

Abstract

The application discloses a Cu / NH2-MIL-125(Ti) photocatalyst and a preparation method and application thereof, and belongs to the technical field of photocatalytic sterilization. The method disperses NH2-MIL-125(Ti) into a solvent, adds copper salt to perform a photocatalytic synthesis reaction, and then Cu / NH2-MIL-125(Ti) photocatalyst is obtained. In the prepared photocatalyst, Cu ions form a coordination bond with organic ligands of NH2-MIL-125(Ti). The cycle stability of the photocatalyst is effectively improved, and the photocatalyst can be applied to water environments containing various bacteria including escherichia coli and bacillus subtilis.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic sterilization technology, and more specifically, relates to a Cu / NH2-MIL-125(Ti) photocatalyst, its preparation method and application. Background Technology

[0002] In recent years, rapid industrialization has posed serious challenges to the aquatic environment upon which humanity depends for survival. Pathogens multiply and spread rapidly in water, severely impacting public health, and the shortage of safe drinking water is a serious problem. Currently, traditional sterilization technologies, such as chemical disinfection, ultraviolet irradiation, and heat treatment, while effective to some extent, also have many problems. For example, chemical disinfectants may produce harmful byproducts, the sterilization effect of ultraviolet irradiation may be affected by water quality, and heat treatment suffers from excessive energy consumption.

[0003] Metal-organic frameworks (MOFs), as a novel type of nanomaterial, have attracted much attention due to their unique porous structure, high specific surface area, and tunable chemical functions. These materials have shown great potential in fields such as photocatalysis, gas storage, and separation technology, particularly in water treatment and photocatalytic sterilization. Chinese patent CN115193484A discloses a photocatalytic sterilization MOF material and its preparation materials and methods; this application successfully prepared MOFs on the surface of a metal oxide (core material) using a hot solvent and applied them to photocatalytic sterilization. Although the MOF material prepared by this patent has a good sterilization effect, it does not solve the biggest problem of MOF materials—material stability.

[0004] A search revealed that patent CN115999642A discloses a TiO2 / CuS / MIL-125-NH2 heterojunction photocatalyst, using MIL-125-NH2 as a substrate and CuS and TiO2 nanoparticles on the surface. The preparation method of this heterojunction photocatalyst includes: dissolving MIL-125-NH2 (Ti / Cu) and thioacetamide in ethanol, followed by heat treatment to obtain TiO2 / CuS / MIL-125-NH2. Patent CN115219572A discloses a method for detecting nitrate ions using a MOF electrode, where Cu... 2+Doping NH2-MIL-125(Ti) yields a metal-organic framework material (NH2-MIL-125(Ti)-Sal-Cu). For example, patent CN114471727A discloses the reaction of 2-aminoterephthalic acid as a raw material with copper salt and tetrabutyl titanate to obtain the NH2-MIL-125(Cu / Ti) intermediate. All of these patents disclose the introduction of metallic Cu into NH2-MIL-125(Ti), but they all employ a solvothermal method. The solvothermal method suffers from the problems of high temperature leading to sintering of the supported metal and long processing time, resulting in severe agglomeration of metallic Cu on the surface, affecting the catalyst activity and failing to effectively improve the photostability of NH2-MIL-125(Ti). Summary of the Invention

[0005] 1. The problem to be solved To address the problem of poor photostability of existing MOF materials, this invention provides a Cu / NH2-MIL-125(Ti) photocatalyst, its preparation method, and its application.

[0006] 2. Technical Solution To solve the above problems, the technical solution adopted by the present invention is as follows: This invention significantly improves the stability of the original NH2-MIL-125(Ti) material by loading Cu onto NH2-MIL-125(Ti).

[0007] The specific steps include: dispersing NH2-MIL-125(Ti) solid powder in a solvent, adding copper salt to carry out photocatalytic synthesis reaction, centrifuging to obtain solid; washing with solvent A, and drying in a vacuum environment at 60~80℃ for 12~16 h to obtain Cu / NH2-MIL-125(Ti) photocatalyst.

[0008] Furthermore, the copper salt is one or more of copper sulfate, copper nitrate, or copper chloride.

[0009] Furthermore, the molar ratio of the copper salt to NH2-MIL-125(Ti) is (0.0035~0.04):1.

[0010] Furthermore, the photocatalytic synthesis reaction is carried out using light intensity of 40~80 mW / cm². 2 The reaction was carried out using visible light with a wavelength of 400~780 nm, for a reaction time of 2~3 h, and with a stirring rate of 500~800 rpm / min.

[0011] Furthermore, solvent A is a solution containing an organic solvent that can disperse NH2-MIL-125(Ti) and copper salt. Preferably, it is a mixed solution of methanol and deionized water, with a volume ratio of methanol to deionized water of (180~250):(8~12). Ethanol or other solvents can also be used for mixing to disperse the reaction substrate.

[0012] The NH2-MIL-125(Ti) can be a commercially available product or a laboratory-prepared NH2-MIL-125(Ti). A method for preparing NH2-MIL-125(Ti) includes the following steps: mixing tetrabutyl titanate, 2-aminoterephthalic acid, N,N-dimethylformamide, and a methanol solution; keeping the mixed solution at 120~180℃ for 24~72 h, cooling to room temperature, and centrifuging to obtain a solid; washing the solid with solvent B, and drying it under vacuum at 60~80℃ for 12~16 h to obtain NH2-MIL-125(Ti) solid powder. The solvent B is preferably methanol and N,N-dimethylformamide, but ethanol or other solvents can also be used for washing to remove unreacted organic matter and solvent.

[0013] Furthermore, the molar ratio of tetrabutyl titanate to 2-aminoterephthalic acid is (3~5):1; and the volume ratio of N,N-dimethylformamide to methanol solution is (8~10):1.

[0014] The theoretical copper loading in the prepared Cu / NH2-MIL-125(Ti) is 0.2%~1%. Cu is introduced into NH2-MIL-125(Ti), and its surface includes Cu particles, Cu(Ⅰ), and Cu(Ⅱ). Compared to the solvothermal method for loading Cu, this patent uses a photodeposition method to prepare Cu-loaded MOFs, resulting in uniform dispersion of Cu particles (Cu(0)) in the material. Figure 2The Cu particles have an average diameter of 8.7 nm, and the Cu ions exist in different valence states, Cu(I) and Cu(II). When the material is irradiated by light, the Cu particles and MOFs are excited and undergo electronic transitions to generate photogenerated electron-hole pairs. Electrons in the MOFs are transferred to Cu(II) through Cu-N bonds, transforming into Cu(I). Holes act on the reaction substrate, but Cu(I) is unstable. Therefore, in this application, some Cu particles are also generated on the NH2-MIL-125(Ti) surface. The Cu particles accept electrons from Cu(I), improving the stability of Cu(I), promoting the transfer of electrons from MOFs to Cu(II), enhancing the material's resistance to light fading, and improving the stability of MOFs. It is worth noting that the average particle size of Cu particles in this application is controlled to be 8.7 nm, which are finely and diffusely distributed on NH2-MIL-125(Ti). Excessively large Cu particles not only fail to enhance the photostability of MOFs materials, but also reduce the stability of MOFs materials. This is because, on the one hand, excessive Cu accumulation on the MOFs surface affects the absorption of light by the catalyst and affects the catalytic performance; on the other hand, excessively large Cu particles cause agglomerated Cu particles of varying sizes, which not only fail to promote the separation of photogenerated electrons and holes, but may also become recombination centers for photogenerated charge carriers.

[0015] Furthermore, by controlling the ratio of Cu(I) to Cu(II) at (1.5-3):(7-8.5) through photodeposition, on the one hand, the ratio of Cu(I) to Cu(II) determines whether the photogenerated electrons generated on MOFs can be transferred in time without accumulation. On the other hand, Cu(I) is unstable and needs to receive electrons from Cu(I) through Cu particles. Considering that the transfer of electrons to Cu particles should not be too fast, otherwise the Cu particles will grow, which is not conducive to the stability of MOFs materials.

[0016] The stability of MOFs is mainly affected by factors such as the strength of metal-ligand interactions, the steric hindrance of the MOF structure, and light attenuation. Although existing techniques can photodeposit metals such as Pd and Ce onto MOF nanosheets, these materials all have high redox potentials, making it difficult to transfer photogenerated electrons in a timely manner. Therefore, this application introduces Cu, which has a lower redox potential. First, by forming Cu-N coordination bonds, the stability of the framework is enhanced, and the strong coordination bonds are conducive to electron transport, thus achieving effective separation of photogenerated carriers in MOFs materials. Second, the coordination of Cu(II) ligands with MOFs materials increases the steric hindrance of MOFs materials, making the MOFs material structure more stable. Finally, Cu ions can act as acceptors for photogenerated carriers, promoting the separation of photogenerated carriers and improving the stability of materials while improving photocatalytic efficiency. After Cu particles are loaded onto MOFs, when light irradiates the surface of Cu particles, it excites electron transitions in Cu to generate electron-hole pairs, enhancing the material's resistance to light fading and protecting the stability of MOFs structures. It is worth noting that the introduction of Cu(II) and its interaction with MOFs materials causes changes in bonding torque, which easily leads to the polarization of TiO6 octahedral groups, generating vacancies and metal defects, which is conducive to the redox reaction.

[0017] The aforementioned photocatalysts can be widely applied to kill bacteria in aquatic environments. The introduction of Cu can improve the photocatalytic sterilization efficiency of Cu / NH2-MIL-125(Ti) by enhancing the utilization efficiency of visible light and promoting the transfer of photogenerated charge carriers. Furthermore, the introduction of Cu increases the stability of Cu / NH2-MIL-125(Ti), maintaining a high sterilization rate against E. coli even after four sterilization cycles.

[0018] 3. Beneficial effects Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In this invention, Cu is loaded onto titanium-based metal-organic framework NH2-MIL-125(Ti) by photodeposition. The successfully loaded Cu ions form stronger coordination bonds and greater steric hindrance with the organic ligands of NH2-MIL-125(Ti), and the Cu species on the surface promote the transfer of photogenerated electrons, thereby enhancing the stability of the MOF structure. After four cycles of sterilization, the sterilization rate against Escherichia coli remains at a high level. (2) The Cu / NH2-MIL-125(Ti) photocatalyst of the present invention introduces a low dose of copper ions, which improves the separation rate of photogenerated electron-hole pairs of the material without destroying the original NH2-MIL-125(Ti) crystal structure, effectively expands the light response range of NH2-MIL-125(Ti) material in the visible light region, and further improves its photocatalytic performance. (3) The Cu / NH2-MIL-125(Ti) photocatalyst prepared in this invention still has excellent bactericidal performance in actual water under different conditions, demonstrating wide applicability and excellent practical application potential; (4) The raw materials used in this invention are easy to obtain and the preparation method is simple, making it suitable for large-scale production. Attached Figure Description

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless specifically indicated, these drawings are intended only to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0020] Figure 1 The XRD patterns are those of product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1 of the present invention. Figure 2 The images show HRTEM images of product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1 of the present invention. Figure 2 a is an HRTEM image of product B1 obtained in Example 1 of the present invention, where the black circle represents the copper particles (average particle size 8.7 nm). b is a TEM image of product D1 obtained in Comparative Example 1. c is a dark field transmission electron microscope image of product B1 obtained in Example 1. d is a diagram of the interplanar spacing of Cu particles in product B1 obtained in Example 1. Figure 3 The Cu 2p XPS spectrum of product B1 obtained in Example 1 of this invention; Figure 4 The UV-vis-DRS (a), band gap (b), parasitic photocurrent response (c), and impedance diagram (d) of product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1 are shown. Figure 5 The images show the bactericidal effects of products B1-B4 obtained in Examples 1-4 and product D1 obtained in Comparative Example 1 on Escherichia coli. Figure 6 The diagram shows the cyclic sterilization effect of product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1. Figure 7 SEM images of product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1 before and after cycling. Figure 8 The image shows the bactericidal effect of product B1 obtained in Example 1 of the present invention on Escherichia coli and Bacillus subtilis under the same conditions. Figure 9This is a diagram showing the bactericidal effect of product B1 obtained in Example 1 of the present invention in actual water bodies; Figure 10 The image shows the bactericidal effect of the active species generated from product B1 obtained in Example 1 of this invention. Figure 11 This is a schematic diagram of the coordination structure of Cu / NH2-MIL-125(Ti) of the present invention. Detailed Implementation

[0021] The following detailed description of exemplary embodiments of the invention is taken with reference to the accompanying drawings, which form part of the description and illustrate exemplary embodiments in which the invention may be practiced. While these exemplary embodiments have been described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be implemented and various changes may be made to the invention without departing from the spirit and scope thereof. The more detailed description of embodiments of the invention below is not intended to limit the scope of the claimed invention, but is merely illustrative and not restrictive of the description of the features and characteristics of the invention, to suggest the best mode for carrying out the invention, and is sufficient to enable those skilled in the art to practice the invention. Therefore, the scope of the invention is defined only by the appended claims.

[0022] In this embodiment, the light source has an intensity of 50 mW / cm². 2 Visible light with wavelengths of 400-780 nm.

[0023] Comparative Example 1 This comparative example provides a method for preparing NH2-MIL-125(Ti) photocatalyst, as detailed below: 0.54 g of 2-aminoterephthalic acid was weighed into a mixed solution containing 9 mL of N,N-dimethylformamide and 1 mL of methanol. Then, 0.26 mL of tetrabutyl titanate was added to the mixture. The resulting solution was magnetically stirred at room temperature for 60 min, then transferred to a polytetrafluoroethylene-lined autoclave and reacted at 150 °C for 72 h. The resulting product was washed three times with methanol and DMF, and dried under vacuum at 80 °C to obtain NH2-MIL-125(Ti), denoted as D1. Its XRD pattern is shown below. Figure 1 As shown, the UV-vis-DRS, band gap, instantaneous photocurrent response, and impedance diagram are as follows: Figure 4 As shown.

[0024] Example 1 This embodiment provides a method for preparing Cu / NH2-MIL-125(Ti) photocatalyst, as detailed below: Weigh 1 g of NH2-MIL-125(Ti) and 0.0039 g of CuSO4·5H2O into 200 mL of pure water, then add 10 mL of methanol. Stir magnetically under visible light for 2 h. Wash the product three times with a methanol-water mixture in equal proportion, dry it under vacuum at 80 °C, and sieve it through a 400-mesh sieve to obtain Cu / NH2-MIL-125(Ti) (Cu to Ti molar ratio of 1:500), denoted as B1. The Cu loading is 0.2 wt%.

[0025] The product B1 obtained in Example 1 and the product D1 obtained in Comparative Example 1 were analyzed and tested respectively.

[0026] The XRD patterns of product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1 are shown below. Figure 1 As shown, the TEM image and the interplanar spacing diagram of Cu particles are as follows: Figure 2 As shown; the Cu2p XPS spectrum of product B1 obtained in Example 1 is as follows. Figure 3 As shown; the UV-vis-DRS, band gap, instantaneous photocurrent response, and impedance diagrams of product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1 are shown in the figure. Figure 4 As shown.

[0027] XRD patterns showed that due to the low loading and uniform dispersion of copper, no characteristic diffraction peaks of copper were observed in the XRD pattern of Cu / NH2-MIL-125(Ti), confirming that loading copper did not alter the crystal structure of the original MOF material. TEM images showed that both Cu / NH2-MIL-125(Ti) and NH2-MIL-125(Ti) had smooth crystal surfaces. Furthermore, the interplanar spacing diagram of Cu particles showed that the distance between copper lattice particles on Cu / NH2-MIL-125(Ti) was 0.21 nm. XPS results showed that copper was loaded onto NH2-MIL-125(Ti) in the form of copper ions. These characterization results demonstrate the successful preparation of the Cu / NH2-MIL-125(Ti) photocatalyst. Figure 4 The results showed that Cu ion loading reduced the band gap of MOFs, expanded the absorption range of visible light, and promoted the separation efficiency of photogenerated electron and hole pairs, thereby enabling photoexcited charge carriers to be rapidly transferred to the particle surface, which in turn enhanced the photocatalytic bactericidal activity.

[0028] Example 2 This embodiment provides a method for preparing Cu / NH2-MIL-125(Ti) photocatalyst. The difference from Example 1 is that in step S2, the mass of CuSO4·5H2O is 0.0056 g, while the rest is the same as in Example 1. This yields Cu / NH2-MIL-125(Ti) (Cu to Ti molar ratio of 1:350), denoted as B2. The Cu loading is 0.29 wt%.

[0029] Example 3 This embodiment provides a method for preparing Cu / NH2-MIL-125(Ti) photocatalyst. The difference from Example 1 is that in step S2, the mass of CuSO4·5H2O is 0.0098 g, while the rest is the same as in Example 1. This yields Cu / NH2-MIL-125(Ti) (Cu to Ti molar ratio of 1:200), denoted as B3. The Cu loading is 0.5 wt%.

[0030] Comparative Example 2 Comparative Example 2 provides a method for preparing Cu / NH2-MIL-125(Ti) photocatalyst. Unlike Example 1, in step S2, the mass of CuSO4·5H2O is 0.0395g, and the rest is the same as in Example 1. Cu / NH2-MIL-125(Ti) (the molar ratio of Cu to Ti is 1:50) is obtained, denoted as D2, and the Cu loading is 2 wt%.

[0031] Example 4 Example 4 uses Escherichia coli as the target degradation product to evaluate the catalytic performance of the photocatalyst. The specific steps are as follows: Using a 300 W xenon lamp as the light source, ultraviolet light was filtered out, and the light intensity was adjusted to 50 mW / cm². 2 Weigh 10 mg of photocatalyst into 20 mL of sterile water, then add E. coli to bring the initial concentration of the cultured E. coli to 10. 6 CFU was adsorbed in the dark for 30 minutes until adsorption and desorption equilibrium was reached. The light source was then turned on, and 100 μL of the mixture was taken every 30 minutes, diluted a certain factor, and evenly spread onto LB solid medium. The culture dishes were then incubated at 37°C for 18 hours to determine the number of viable cells. The number of colonies in the culture dishes was counted after each sterilization reaction. Specific results are as follows: Figure 5 As shown.

[0032] The photocatalysts are products B1-B3 obtained in Examples 1-3 and products D1 and D2 obtained in Comparative Examples 1 and 2, respectively.

[0033] Depend on Figure 5The bactericidal effects of products B1-B3 obtained in Examples 1-3 and products D1 and D2 obtained in Comparative Examples 1 and 2 on *E. coli* show that, under visible light irradiation, products B1-B3 obtained in Examples 1-3 exhibited a higher removal rate of *E. coli* compared to product D1 obtained in Comparative Example 1, and this rate increased with decreasing Cu ion loading. With further increases in Cu loading, the bactericidal effect of product D2 obtained in Comparative Example 2 was significantly lower than that of the products in the Examples. The material with the highest *E. coli* removal rate was product B1 obtained in Example 1, with a Cu loading of 0.2 wt%. The removal rate of *E. coli* reached 99.04% after 120 min. Loading copper ions onto the NH2-MIL-125(Ti) surface can improve the photocatalyst's reactivity.

[0034] The reason is that excessive Cu loading leads to Cu particles accumulating on the surface of MOFs, affecting the catalyst's absorption of light. Furthermore, the agglomerated Cu particles are of varying sizes, which not only fail to promote the separation of photogenerated electrons and holes but may also become recombination centers for photogenerated charge carriers.

[0035] Example 5 Example 5 uses Escherichia coli as the target degradation product to evaluate the cycle stability of the photocatalyst. The specific steps are as follows: Example 5 was carried out according to the method of Example 4, except that product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1 were subjected to four cycles of sterilization experiments, and the killing effect of the photocatalyst on Escherichia coli was tested. The specific results are as follows: Figure 6 As shown.

[0036] Depend on Figure 6 The cyclic sterilization performance graphs of product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1 show that the photocatalytic sterilization performance of D1 decreases significantly with increasing cycle number. The initial sterilization rate against Escherichia coli is 80.03%, and after four cycles, the sterilization rate is 27.97%, a decrease of 65.05%. In contrast, the cyclic sterilization performance of B1 after introducing Cu ions remains relatively stable, decreasing only from the initial 99.04% to the final 83.86%, a decrease of 15.33%. This indicates that the loading of Cu ions effectively improves the stability of NH2-MIL-125(Ti), and the prepared NH2-MIL-125(Ti) has high reusability.

[0037] SEM results were analyzed for B1 and D1 before and after the cycle. Figure 7 As shown.

[0038] Depend on Figure 7The SEM images of product B1 obtained in Example 1 and product D1 obtained in Comparative Example 1 before and after cycling show that the spatial structure of NH2-MIL-125(Ti) collapsed significantly after cycling. In contrast, the introduction of Cu ions produced a completely different result; the spatial structure of Cu / NH2-MIL-125(Ti) remained stable after cycling without significant collapse. This demonstrates that Cu ion loading optimizes the structure and properties of MOF materials, ensuring high structural stability and bactericidal efficacy during repeated use.

[0039] We hypothesize three main reasons for this phenomenon. First, the increase in coordination bonds affects the stability of the framework. The introduction of Cu onto NH2-MIL-125(Ti) forms additional coordination bonds with other functional groups, increasing the framework's connectivity and thus enhancing the material's stability. Second, the recombination of photogenerated electron-hole pairs also influences the structure of MOFs. Cu ions can act as acceptors for photogenerated carriers, promoting their separation and improving photocatalytic efficiency, thereby enhancing the material's stability. Finally, light fading is also a major factor affecting MOF stability. When light irradiates the surface of metal particles, it excites electron transitions in the metal, generating photogenerated electron-hole pairs and enhancing the material's resistance to light fading. Therefore, Cu loading can reduce the stimulation of MOFs by light, maintaining the stability of the MOF structure.

[0040] Example 6 Example 6 was carried out according to the method described in Application Example 1, except that 10 mM •OH quencher isopropanol and 5 mM O2 were added before photocatalytic induced sterilization. - Quenching agent TEMPO, 1mM h + Quenching agents Na2C2O4 and 5 mM 1 O2 quencher histidine, test results are as follows Figure 10 As shown.

[0041] Depend on Figure 10 The bactericidal effect diagram of various species generated by product B1 obtained in Example 1 shows that O2 - •OH, h + , 1 All four active substances, including O2, participate in the photocatalytic degradation of E. coli. Among them, ·OH and h + and 1 O2 is the main active substance in photocatalytic reactions.

[0042] Example 7 Example 7 uses Bacillus subtilis as the target degradation product to evaluate the catalytic performance of the photocatalyst. The specific steps are as follows: The method of Example 4 was followed, and the product B1 obtained in Example 1 was tested. The difference was that the bacteria used had an initial concentration of 10. 6 CFU of Bacillus subtilis, test results as follows Figure 8 As shown.

[0043] Depend on Figure 8 As shown in the bactericidal effect diagram of product B1 obtained in Example 1 against Escherichia coli and Bacillus subtilis under the same conditions, product B1 obtained in Example 1 also has a good bactericidal effect against Bacillus subtilis, indicating that the Cu / NH2-MIL-125(Ti) photocatalyst of the present invention also has a good bactericidal effect against Bacillus subtilis.

[0044] Example 8 Example 8 was carried out according to the method of Example 4, and the product B1 obtained in Example 1 was tested. The difference was that the sterile water was replaced with actual water (passed through a 0.45 μm membrane). The actual water in this example was selected from the Yangtze River, Qingyi River, reed marshes, and tap water, etc. After passing through the membrane, an initial concentration of 10 was added to the water. 6 The results of the CFU E. coli test are as follows: Figure 9 As shown.

[0045] Depend on Figure 9 The bactericidal effect of product B1 obtained in Example 1 in actual water bodies shows that Cu / NH2-MIL-125(Ti) has an inactivation rate of 70% against Escherichia coli in actual water bodies. This indicates that Cu / NH2-MIL-125(Ti) still has high degradation activity against Escherichia coli in actual water bodies.

[0046] Compared to sterile water, the extinguishing rate against E. coli in actual water bodies was reduced. Measurements of key indicators in these water bodies revealed a significant increase in total organic carbon (TOC), total dissolved solids (TDS), and electrical conductivity (EC) compared to sterile water. These parameters significantly affected the photocatalytic bactericidal performance of Cu / NH2-MIL-125(Ti).

[0047] In particular, considering the potential fluctuations in TOC, TDS, and EC content in natural water bodies such as the Yangtze River, this result highlights the practical application potential of Cu / NH2-MIL-125(Ti) in the field of disinfection of different water bodies.

[0048] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention.

[0049] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0050] Furthermore, any simple modifications, alterations, and equivalent structural changes made to the above embodiments based on the essence of the invention shall still fall within the protection scope of the technical solution of this invention.

Claims

1. A Cu / NH2-MIL-125(Ti) photocatalyst, used for photocatalytic sterilization, characterized in that, The photocatalyst contains Cu ions, Cu particles, and NH2-MIL-125(Ti). The Cu ions form Cu-N bonds with NH2-MIL-125(Ti), and the Cu particles are dispersed on NH2-MIL-125(Ti). The average particle size of the Cu particles is 8.7 nm, and the Cu ions include Cu(I) and Cu(II).

2. The Cu / NH2-MIL-125(Ti) photocatalyst according to claim 1, characterized in that, The ratio of Cu(Ⅰ) to Cu(Ⅱ) is (1.5-3):(7-8.5).

3. The Cu / NH2-MIL-125(Ti) photocatalyst according to claim 1, characterized in that, The theoretical loading of Cu is 0.2 wt% to 1 wt%.

4. The method for preparing the Cu / NH2-MIL-125(Ti) photocatalyst according to any one of claims 1-3, characterized in that, The process includes the following steps: dispersing NH2-MIL-125(Ti) in a solvent, adding copper salt to carry out a photocatalytic synthesis reaction, and obtaining a Cu / NH2-MIL-125(Ti) photocatalyst. The photocatalytic synthesis reaction is carried out using light intensity of 40~80 mW / cm. 2 Visible light with wavelengths of 400~780 nm.

5. The preparation method according to claim 4, characterized in that, The molar ratio of the copper salt to NH2-MIL-125(Ti) is (0.0035~0.04):

1.

6. The preparation method according to claim 4, characterized in that, The copper salt is one or more of copper sulfate, copper nitrate, or copper chloride.

7. The preparation method according to claim 4, characterized in that, The reaction time is 2-3 hours, and the stirring rate is 500-800 rpm / min.

8. The preparation method according to claim 4, characterized in that, The Cu / NH2-MIL-125(Ti) photocatalyst was washed with solvent and dried in a vacuum environment at 60~80℃ for 12~16 h.

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