Application of a photocatalytic-pms activation catalyst based on co-mof / tiO2 heterojunction

Abstract

The application discloses an application of a photocatalysis-PMS activation catalyst based on a Co-MOF / TiO2 heterojunction, and specifically, TiO2 nanosheets are coupled with a porphyrin-based MOF to construct a Co-MOF / TiO2 heterojunction hybrid material; the material has the performance of synergistic photocatalysis of persulfate activation and is used for catalyzing a refractory bisphenol A; the compound is an effective synergistic photocatalyst and has many advantages: (i) the porous structure of the metal organic framework promotes the mass transfer of the catalytic process, thereby further promoting the catalytic process; (ii) the chromophore at the center of the porphyrin structure can enhance the light capturing capacity of the metal organic framework (under visible light, photo-induced electrons continuously migrate to the adsorbed PMS, promoting the activation process of the PMS); (iii) the heterojunction formed between TiO2 and Co-porphyrin ligands further promotes the separation of photo-generated carriers.

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis, specifically relating to a photocatalytic PMS-activated catalyst based on Co-MOF / TiO2 heterojunction, its preparation method, and its application. Background Technology

[0002] In recent years, water pollution caused by persistent micropollutants and the global energy crisis have become hot issues of common concern to the international community and the scientific community. Bisphenol A (BPA) is a harmful micropollutant widely used in the polymer industry. It has significant endocrine-disrupting properties, which can adversely affect the human hormonal system, leading to a series of health problems such as cancer and abnormal reproductive systems. In addition, BPA is highly stable in the environment and is difficult to degrade naturally. During industrial production, large amounts of BPA are discharged into rivers, lakes, and soil through wastewater. Even at low concentrations, BPA poses a potential threat to aquatic organisms and human health. Traditional wastewater treatment methods, such as biological treatment, adsorption, ozone, and oxidation, can remove pollutants to some extent, but they are still inefficient and costly in degrading organic pollutants such as BPA. Therefore, developing more effective pollutant removal technologies and applying green energy has become a major demand in the field of environmental protection.

[0003] Advanced oxidation processes (AOPs) have attracted widespread attention in recent years due to their efficient ability to treat organic pollutants. AOPs utilize reactive oxygen species to degrade pollutants, showing particular strength in treating recalcitrant organic pollutants. The application of semiconductor photocatalysts in AOPs can generate free radicals by absorbing light energy, achieving efficient degradation of pollutants. For example, TiO2, a commonly used photocatalytic material, is widely used in wastewater treatment due to its high chemical stability, low cost, and excellent redox properties. However, the wide bandgap (3.2 eV) of TiO2 limits its light absorption capacity in the visible light range, leading to rapid recombination of photogenerated carriers and limiting its catalytic efficiency. Therefore, TiO2 still faces significant challenges in practical applications and requires further improvement.

[0004] To address the limited photocatalytic performance of TiO2, researchers have proposed a strategy to improve photocatalytic efficiency by constructing heterojunctions. Combining TiO2 with semiconductor materials having narrow band gaps can broaden its light absorption range and improve the separation efficiency of photogenerated electrons and holes. In recent years, metal-organic frameworks (MOFs) have gradually become an emerging photocatalytic material due to their tunable structure, large specific surface area, and good photoresponse. Among them, porphyrin-based MOFs, due to their ability to effectively capture visible light and their excellent photoelectric properties, have become an ideal choice for constructing organic-inorganic photocatalysts by combining them with TiO2. Furthermore, persulfate (PMS) activation technology, due to the sulfate radicals (SO42-) generated... 2- PMS (Polymerase Monomer) possesses a high redox potential and is widely used in the removal of recalcitrant organic pollutants. Therefore, combining PMS with photocatalysis to explore its synergistic effect in order to improve catalytic degradation efficiency has become one of the current research hotspots.

[0005] Currently, research on the synergistic effect of PMS activation and photocatalysis is almost nonexistent. Exploring the synergistic catalytic mechanism between the two is of great significance for improving the application efficiency of AOPs technology. Therefore, this study constructed a hybrid material with synergistic photocatalysis-PMS activation function by coupling TiO2 nanosheets with porphyrin-based MOFs for the degradation of BPA pollutants in water. Experiments show that this hybrid material has high photogenerated carrier separation efficiency under visible light, and the PMS activation process further enhances the oxidation capacity of the material, significantly improving the degradation efficiency of BPA. Summary of the Invention

[0006] The purpose of this invention is to provide a photocatalytic-PMS activated catalyst based on Co-MOF / TiO2 heterojunction, its preparation method and application, which solves the technical problem of low catalytic efficiency of traditional photocatalytic materials. Due to the synergistic effect of the photocatalytic-PMS activation coupling system, the catalyst exhibits good photocatalytic degradation effect on BPA.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing a photocatalytic-PMS activated catalyst based on a Co-MOF / TiO2 heterojunction involves adding TiO2 nanosheets to DMF, ultrasonically dispersing them uniformly, then adding Co-MOF, stirring for 6-18 h, centrifuging to collect the precipitate, washing and drying it to obtain the catalyst. The Co-MOF accounts for 5-40% of the total mass of the Co-MOF and TiO2 nanosheets. The washing is performed using ethanol, with 3-6 washing cycles. The drying temperature is 30-80℃, and the drying time is 10-20 h.

[0009] Further, the preparation process of Co-MOF is as follows: Cobalt acetate tetrahydrate is dissolved in methanol to form solution A, and porphyrin ligand is dissolved in chloroform to form solution B. Solution A and solution B are mixed and reacted in a high-pressure reactor at 60-120℃ for 12-36h. After natural cooling to room temperature, the mixture is centrifuged, the solid is collected, washed with ethanol, and then dried. The molar ratio of cobalt acetate tetrahydrate to porphyrin ligand is (2-10):1. The concentration of cobalt acetate in solution A is 20-30 mmol / L, and the concentration of porphyrin ligand in solution B is 1-10 mmol / L. The number of ethanol washes is 3-6 times. The drying temperature is 30-80℃, and the drying time is 10-20h.

[0010] Further, the preparation process of TiO2 nanosheets is as follows: hydrofluoric acid is added dropwise to tetraisopropyl titanate, stirred evenly, and then reacted in a high-pressure reactor at 160-220℃ for 12-36 h. After natural cooling to room temperature, the solid is collected by centrifugation, washed with ethanol, and then dried. The volume ratio of hydrofluoric acid to tetraisopropyl titanate is 1:(8-9). The concentration of hydrofluoric acid is 35-40 wt%; the number of ethanol washes is 3-6 times; the drying temperature is 30-80℃; and the drying time is 10-20 h.

[0011] The above preparation method yields a photocatalytic PMS-activated catalyst based on a Co-MOF / TiO2 heterojunction.

[0012] The above-mentioned application of the photocatalytic-PMS activated catalyst based on Co-MOF / TiO2 heterojunction in the photocatalytic degradation of bisphenol A involves adding the photocatalytic-PMS activated catalyst based on Co-MOF / TiO2 heterojunction to a solution containing bisphenol A, using a 50W LED lamp as the light source, and adding PMS (hydrogen persulfate) under circulating water cooling to carry out the photocatalytic degradation of bisphenol A.

[0013] Furthermore, the concentration of bisphenol A in the solution containing bisphenol A is 10-50 mg / L, and the amount of Co-MOF / TiO2 heterojunction composite photocatalyst added is 0.1-0.3 g / L and the amount of PMS added is 0.2-0.4 g / L, based on the solution containing bisphenol A.

[0014] Compared with existing methods, the advantages of this invention are as follows:

[0015] 1. The preparation method of the photocatalytic-PMS activated catalyst based on Co-MOF / TiO2 heterojunction provided by this invention significantly improves photocatalytic performance: This invention constructs a highly efficient organic-inorganic hybrid photocatalyst by combining TiO2 nanosheets with porphyrin-based metal-organic framework (MOF) materials. Although traditional TiO2 has high chemical stability and redox capabilities, its wide bandgap (3.2 eV) limits its absorption range under visible light, resulting in insufficient photocatalytic performance. This invention, by combining with porphyrin-based MOF, successfully broadens the spectral response range of the catalytic material, particularly enhancing its light absorption capacity in the visible light region. The organic ligands of the porphyrin-based MOF not only act as photosensitive antennas, efficiently capturing visible light, but also promote the separation of photogenerated electrons and holes, avoiding rapid recombination of electrons and holes. This improved carrier separation efficiency allows the material to generate more reactive oxygen species (ROS) during photocatalysis, thereby significantly improving the degradation efficiency of organic pollutants such as bisphenol A (BPA).

[0016] 2. The photocatalytic-PMS activation catalyst based on Co-MOF / TiO2 heterojunction provided by this invention possesses a synergistic catalytic mechanism. Compared to conventional single photocatalytic mechanisms, the synergistic effect between the heterojunction composite photocatalysts significantly enhances the generation of active species. The high redox potential of cobalt ions effectively activates PMS into a strong oxidant. The excellent light absorption performance of the heterojunction composite catalyst enables the generation of photogenerated electron-hole pairs under visible light irradiation. These photogenerated carriers can be effectively captured by adsorbed PMS, further promoting the PMS activation process. The synergistic effect of PMS activation and photocatalysis in the composite catalyst generates a large number of strong oxide species, thereby achieving highly efficient removal of recalcitrant BPA pollutants.

[0017] 4. The photocatalytic-PMS activated catalyst based on Co-MOF / TiO2 heterojunction provided by this invention has strong adaptability to complex water bodies: The hybrid material of this invention exhibits stable and efficient catalytic degradation performance in a wide range of reaction systems, making it suitable for different types of water environments. Through synergistic PMS activation and photocatalytic reaction, this invention has excellent performance in different reaction systems under neutral conditions. In addition, this invention also has strong anti-interference ability against coexisting ions such as chloride ions and nitrate ions that may exist in water bodies, ensuring its wide applicability in actual water treatment, especially maintaining high degradation efficiency in complex wastewater treatment environments. Attached Figure Description

[0018] Figure 1The crystal structure of Co-MOF is shown below: (a) the basic structural unit in Co-MOF; perspective view of Co-MOF structure along the crystallographic c-axis; (b) local pore structure; (c) space-filling diagram; (d) framework diagram (metal-metal connection).

[0019] Figure 2 The band structure of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 is shown in the following figures: (a) UV-vis DRS spectra, (b) calculated band gap.

[0020] Figure 3 The following are the BPA removal effects of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 under different systems; the degradation kinetics (a) and pseudo-first-order kinetic fit (b) of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 on BPA under visible light; the degradation kinetics (c) and pseudo-first-order kinetic fit (d) of the catalyst prepared in Example 3 on BPA under visible light and PMS conditions. Experimental conditions: pH=7; [PMS]=1.2 mM; [catalyst] = 0.4 g / L; [BPA]=10 mg / L;

[0021] Figure 4 The effects of the catalyst in Example 3 on BPA removal rate under different conditions are as follows: (a) Effects of various anions on BPA removal rate. (b) Effects of various anions on BPA removal rate in deionized water, tap water, lake water, river water, and simulated seawater. Experimental conditions: pH=7; [PMS]=1.2 mM; [catalyst] = 0.4 g / L; [BPA]=10 mg / L;

[0022] Figure 5 The following are the cycling performance and cycling stability of the catalyst prepared in Example 3: (a) Cyclic degradation experiment of BPA; (b) PXRD patterns before and after catalysis. Detailed Implementation

[0023] To better understand the present invention, the following embodiments are provided for further illustration. These embodiments are only for explaining the present invention and do not constitute any limitation on the present invention.

[0024] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products.

[0025] 5,10,15,20-Tetra(4-pyridyl)porphyrin (porphyrin ligand) (Zhengzhou Alpha Chemical Co., Ltd.), Cobalt acetate tetrahydrate (Shanghai Maclean Biochemical Technology Co., Ltd.), Tetraisopropyl titanate (Shanghai Maclean Biochemical Technology Co., Ltd.), Hydrofluoric acid, methanol, ethanol, N,N-dimethylformamide (Chengdu Kelong Chemical Co., Ltd.). Example

[0026] A method for preparing a photocatalytic-PMS activated catalyst based on a Co-MOF / TiO2 heterojunction includes the following steps:

[0027] Step S1: Dissolve 0.25 g of cobalt acetate tetrahydrate (1 mmol) in 40 mL of methanol and sonicate for 10 min to form solution A; dissolve 0.13 g of porphyrin ligand (0.2 mmol) in 40 mL of chloroform and sonicate for 10 min to form solution B; mix solutions A and B, transfer the mixture to a 100 mL Teflon-lined stainless steel autoclave, and react at 90 °C for 24 h; after naturally cooling to room temperature, collect the formed purple crystals by centrifugation and wash five times with anhydrous ethanol to remove unreacted ligands and metal salts; the final washing product is dried under vacuum at 60 °C for 12 h to obtain Co-MOF.

[0028] Step S2: Under continuous magnetic stirring, 6 mL of 40 wt% hydrofluoric acid was added dropwise to 50 mL of tetraisopropyl titanate. After stirring for 10 min, the mixture was transferred to a 100 mL Teflon-lined stainless steel autoclave and reacted at 190 °C for 24 h. After naturally cooling to room temperature, the formed gel-like white precipitate was collected by centrifugation and washed five times with anhydrous ethanol to remove hydrofluoric acid from the system. The final washing product was vacuum dried at 60 °C for 12 h to obtain TiO2 nanosheets.

[0029] Step S3: Add 0.1 g of TiO2 nanosheets to 30 mL of DMF and sonicate for 1 h to form a uniform dispersion; then add 5 mg of Co-MOF to the solution and continue stirring for 12 h, wherein the mass of Co-MOF accounts for 5% of the total mass. Collect the precipitate by centrifugation, wash it 5 times with anhydrous ethanol, and dry it at 60 °C for 12 h to obtain photocatalytic-PMS activated catalyst 1 based on Co-MOF / TiO2 heterojunction. Example

[0030] A method for preparing a photocatalytic-PMS activated catalyst based on a Co-MOF / TiO2 heterojunction includes the following steps:

[0031] Step S1: Same as step S1 in Example 1;

[0032] Step S2: Same as step S2 in Example 1;

[0033] Step S3: Add 0.1 g of TiO2 nanosheets to 30 mL of DMF and sonicate for 1 h to form a uniform dispersion; then add 11 mg of Co-MOF to the solution and continue stirring for 12 h, wherein the mass of Co-MOF accounts for 10% of the total mass. Collect the precipitate by centrifugation, wash it 5 times with anhydrous ethanol, and dry it at 60 °C for 12 h to obtain photocatalytic-PMS activated catalyst 2 based on Co-MOF / TiO2 heterojunction. Example

[0034] A method for preparing a photocatalytic-PMS activated catalyst based on a Co-MOF / TiO2 heterojunction includes the following steps:

[0035] Step S1: Same as step S1 in Example 1;

[0036] Step S2: Same as step S2 in Example 1;

[0037] Step S3: Add 0.1 g of TiO2 nanosheets to 30 mL of DMF and sonicate for 1 h to form a uniform dispersion; then add 25 mg of Co-MOF to the solution and continue stirring for 12 h, wherein the mass of Co-MOF accounts for 20% of the total mass; collect the precipitate by centrifugation, wash it 5 times with anhydrous ethanol, and dry it at 60 ℃ for 12 h to obtain photocatalytic-PMS activated catalyst 3 based on Co-MOF / TiO2 heterojunction. Example

[0038] A method for preparing a photocatalytic-PMS activated catalyst based on a Co-MOF / TiO2 heterojunction includes the following steps:

[0039] Step S1: Same as step S1 in Example 1;

[0040] Step S2: Same as step S2 in Example 1;

[0041] Step S3: Add 0.1 g of TiO2 nanosheets to 30 mL of DMF and sonicate for 1 h to form a uniform dispersion; then add 43 mg of Co-MOF to the solution and continue stirring for 12 h, wherein the mass of Co-MOF accounts for 30% of the total mass; collect the precipitate by centrifugation, wash it 5 times with anhydrous ethanol, and dry it at 60 ℃ for 12 h to obtain photocatalytic-PMS activated catalyst 4 based on Co-MOF / TiO2 heterojunction.

[0042] Comparative Example 1

[0043] A method for preparing a Co-MOF photocatalyst includes the following steps:

[0044] Solution A was prepared by dissolving 0.25 g of cobalt acetate tetrahydrate in 40 mL of methanol and sonicating for 10 min. Solution B was prepared by dissolving 0.13 g of porphyrin ligand in 40 mL of chloroform and sonicating for 10 min. Solutions A and B were mixed and transferred to a 100 mL Teflon-lined stainless steel autoclave. The mixture was then reacted at 90 °C for 24 h. After natural cooling to room temperature, the formed purple crystals were collected by centrifugation and washed five times with anhydrous ethanol to remove unreacted ligands and metal salts. The final washing product was dried under vacuum at 60 °C for 12 h to obtain the Co-MOF photocatalyst.

[0045] Comparative Example 2

[0046] A method for preparing a TiO2 nanosheet photocatalyst includes the following steps:

[0047] Under continuous magnetic stirring, 6 mL of 40% hydrofluoric acid was added dropwise to 50 mL of tetraisopropyl titanate. After stirring for 10 min, the mixture was transferred to a 100 mL Teflon-lined stainless steel autoclave and reacted at 190 °C for 24 h. After naturally cooling to room temperature, the resulting gel-like white precipitate was collected by centrifugation and washed five times with anhydrous ethanol to remove hydrofluoric acid. The final washing product was vacuum dried at 60 °C for 12 h to obtain TiO2 nanosheet photocatalyst.

[0048] Performance testing

[0049] 1. Photocatalytic performance

[0050] (1) Irradiation / Photocatalyst / PMS: The photocatalyst (20 mg) was placed in a reactor containing BPA solution (CO = 20 mg / L, 100 mL), and then sonicated for 2 min to fully disperse the catalyst. A 50 W LED (λ > 420 nm) was used as the light source; the reactor was surrounded by a quartz sleeve filled with circulating cooling water; at the same time, 30 mg of PMS was injected to start the catalytic reaction; 2 mL of sample was intermittently and immediately drawn with a syringe, and quenched with 50 μL of Na2S2O3 solution (0.5 M). The suspended particles were then separated through a 0.22 µm filter for subsequent analysis; the instantaneous concentration at different time points was monitored by a UV-Vis spectrometer to determine the change of BPA over time.

[0051] (2) Irradiation: omit photocatalyst and PMS, otherwise the same as (1);

[0052] (3) PMS: omit the photocatalyst and light source, otherwise the same as (1);

[0053] (4) Irradiation / PMS: omit the photocatalyst, otherwise the same as (1);

[0054] (5) Photocatalyst / PMS: omit the light source, otherwise the same as (1);

[0055] (6) Light / photocatalyst: PMS is omitted, otherwise the same as (1);

[0056] 2. Recyclability

[0057] The photocatalyst (20 mg) from Example 3 was added to a reaction solution containing BPA (100 mL, 10 mg / mL), and then sonicated for 2 min to ensure thorough dispersion. Subsequently, 30 mg of PMS was added. During the reaction, 2 mL of the reaction solution was extracted every 5 min, and the supernatant was collected by centrifugation for BPA concentration detection, using the same method as the photocatalytic performance test in the performance testing. The collected solid was redispersed back into the reaction solution. After one cycle, the catalyst was collected by centrifugation, washed three times with water, vacuum dried, and then the above steps were repeated.

[0058] Figure 1 To obtain the crystal structure of the prepared Co-MOF, from Figure 1 It is known that in Co-MOF, each Co ion is located at the porphyrin center, and the porphyrin ligands above and below it and the adjacent porphyrin ligands are connected by coordination bonds to form a 3D metal-organic framework with a hexagonal porous structure.

[0059] Figure 2 The band structure of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 was studied. The optical properties of the catalysts were evaluated to assess their potential as photocatalysts. Figure 2 (a) shows the UV-vis DRS spectrum of the catalyst; Comparative Example 2 (pure TiO2) showed almost no absorption above 400 nm; compared with Comparative Example 2, the samples of Examples 1-4 exhibited stronger light absorption, with peaks at 429, 518, 552, 592, and 644 nm related to the pp* transition between the lowest unoccupied molecular orbital and the highest occupied molecular orbital; the band gap value of the photocatalyst was derived according to the Kubelka-Munk theory. Figure 2 (b) The band gaps of Comparative Example 1, Comparative Example 2 and Examples 1-4 were 2.56, 3.22, 3.14, 3.06, 2.96 and 2.85 eV, respectively. It is worth noting that the introduction of Co-MOF will bring new impurity levels into the band gap, thereby reducing the band gap of the photocatalyst.

[0060] Figure 3 To investigate the photocatalytic properties of the material through a series of comparative experiments; Figure 3(a) The photocatalytic performance of the catalysts obtained in Comparative Examples 1-2 and Examples 1-4 for BPA under visible light was evaluated. The photocatalytic performance of the catalysts obtained in Comparative Examples 1-2 for BPA was limited; the performance of the catalysts obtained in Examples 1-4 was better than that of Comparative Examples 1 and 2 alone; the degradation efficiency of the catalysts increased with the increase of Co-MOF content; the degradation rates of BPA by the catalysts obtained in Examples 1-4 reached 60.7%, 90.1%, 94.1% and 79.3% respectively within 60 min; this was attributed to the redshift of visible light absorption and the formation of heterojunction structure; among these composite materials, the photocatalytic performance of the catalyst obtained in Example 3 was the best; the photocatalytic kinetics study adopted quasi-first-order (Equation (1)) and quasi-second-order (Equation (2)) models;

[0061]

[0062] Among them, C0 and C t denoted as the initial BPA concentration and the BPA concentration at time t min, respectively, and k1 and k2 represent the quasi-first-order kinetic constant and the quasi-second-order kinetic constant, respectively.

[0063] The BPA reduction rate of these samples conforms to a quasi-first-order reaction kinetic model; the BPA removal rate conforms to first-order reaction kinetics, and the apparent reaction kinetic constant for BPA degradation by the catalyst obtained in Example 3 was calculated to be 0.0444 min. -1 This is 7 times and 57 times the reaction kinetic constants of Comparative Example 1 and Comparative Example 2, respectively. Figure 3 (b)).

[0064] Considering the structural characteristics of Co-MOF and the potential PMS activation properties of Co-MOF, the degradation performance of BPA under different conditions was tested, as detailed below. Figure 3 (c), 3 (d) and Table 1 are shown.

[0065] like Figure 3 As shown in (c), the degradation rate of BPA was less than 10% in the presence of visible light or PMS alone after 60 min; in the visible light / PMS system, the degradation rate of BPA was only 21.3% after 60 min. In the presence of PMS, the degradation performance of BPA in the Example 3 / PMS or light / Example 3 / PMS system was significantly greater than that in the light / Example 3 system, indicating that Example 3 could activate PMS. On the other hand, the degradation performance of the light / Example 3 / PMS system was significantly greater than that of the Example 3 / PMS system. This suggests that visible light also plays an important role in the activation of the PMS system in Example 3. The removal rate of BPA conforms to first-order reaction kinetics, and the calculated apparent reaction kinetic constant for the degradation of BPA in the light / Example 3 / PMS system is 0.0730 min. -1This is 1.6 times the reaction kinetic constant of the light / Example 3 and Example 3 / PMS systems. Figure 3 (d)); The above results indicate that the catalyst obtained in Example 3 has both visible light photocatalytic performance and PMS activation performance, and exhibits excellent performance in the degradation of BPA.

[0066] Table 1 Comparison of BPA removal effects of the catalyst obtained in Example 3 under different conditions

[0067] condition Degradation rate (%) <![CDATA[Reaction rate constant (min -1 ).]]> illumination 0.185 0 PMS 11.259 0.0018 Illumination / PMS 21.344 0.0038 Example 3 / PMS 94.451 0.0464 Illumination / Example 3 94.041 0.0444 Illumination / Example 3 / PMS 99.709 0.0730

[0068] Figure 4 Real water bodies contain a certain amount of coexisting ions; several inorganic anions (Cl-) with a concentration of 3 mM were introduced into the light / Example 3 / PMS system. - NO3 - CO3 2- HPO3 - HCO3 - and SO4 2- () Figure 4 (a)); The results showed that the inhibitory effect of all inorganic anions was negligible; compared with the control group experiment, the addition of Cl... - NO3 - and CO3 2- Afterwards, the degradation rate of BPA remained almost unchanged; Cl - Can react with SO4 2- The reaction produces less reactive •Cl and •Cl2. - Anion, NO3 - It can interact with electrons to form NO2 - SO4 2- It has a slight inhibitory effect on BPA degradation because SO4... 2- It will hinder the forward reaction in the activation of PMS, leading to SO4 2- Reducing the amount of HCO3 decreases the degradation efficiency; adding HCO3... - and HPO4 2- It also inhibits the degradation of BPA. This is because HCO3... - and HPO4 2- It can react with •OH and SO4 2- The reaction forms species with lower reactivity (•HCO3, HPO4). 2- This consumes •OH and SO4. 2- Ultimately, this reduces BPA degradation. Furthermore, considering the potential for different reaction media in practical applications, the effects of light / Example 3 / PMS system on BPA degradation in different media were investigated; for example... Figure 4As shown in (b), there was no significant difference in the inhibition effect of the light / Example 3 / PMS system on BPA in deionized water, tap water, lake water, river water and simulated seawater, which indicates that the catalyst has outstanding potential for practical application.

[0069] Figure 5 Cyclic usability and stability testing of the illumination / Example 3 / PMS system; such as Figure 5 As shown in (a), after five cycles, the light / Example 3 / PMS system still maintained good BPA removal performance, with a removal rate of over 90%, indicating good reusability. To investigate the stability of the catalyst structure before and after the reaction, the PXRD patterns of the catalyst obtained in Example 3 before and after the reaction were measured. The PXRD patterns of the catalyst obtained in Example 3 before and after the reaction ( Figure 5 (b) shows almost no change from the state before the reaction. These results demonstrate the structural stability and free radical scavenging ability of the catalyst obtained in Example 3 in this particular system, which is the basis for the recyclability of the catalyst obtained in Example 3.

[0070] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

[0071] The foregoing has shown and described the basic principles and main features of the present invention and its advantages. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all changes falling within the meaning and scope of the equivalents of the claims be included within the present invention, and no reference numerals in the claims should be regarded as limiting the scope of the claims.

[0072] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. The application of a photocatalytic-PMS activated catalyst based on a Co-MOF / TiO2 heterojunction in the photocatalytic degradation of bisphenol A, characterized in that, The catalyst preparation method involves adding TiO2 nanosheets to DMF, ultrasonically dispersing them evenly, then adding Co-MOF, stirring for 6-18 h, centrifuging to collect the precipitate, washing and drying it. Co-MOF accounts for 5-40% of the total catalyst mass, and the ligand used in Co-MOF is 5,10,15,20-tetra(4-pyridyl)porphyrin. The Co-MOF / TiO2 heterojunction composite photocatalyst is added to a solution containing bisphenol A, and a 50W LED lamp is used as the light source. Under circulating water cooling, PMS is added to carry out photocatalytic degradation of bisphenol A.

2. The application according to claim 1, characterized in that, The preparation process of Co-MOF is as follows: Cobalt acetate tetrahydrate is dissolved in methanol to form solution A, and porphyrin ligand is dissolved in chloroform to form solution B. Solutions A and B are mixed and reacted in a high-pressure reactor at 60-120℃ for 12-36 h. After natural cooling to room temperature, the mixture is centrifuged, the solid is collected, washed with ethanol, and then dried. The molar ratio of cobalt acetate tetrahydrate to porphyrin ligand is (2-10):

1. The concentration of cobalt acetate in solution A is 20-30 mmol / L, and the concentration of porphyrin ligand in solution B is 1-10 mmol / L. The number of ethanol washes is 3-6 times. The drying temperature is 30-80℃, and the drying time is 10-20 h.

3. The application according to claim 1, characterized in that, The degradation process of bisphenol A is a synergistic process of photocatalysis and PMS activation, and its reaction rate is higher than that obtained by using only photocatalysis and only PMS activation.

4. The application according to claim 2, characterized in that, The concentration of bisphenol A in the solution is 10~50 mg / L. Based on the solution containing bisphenol A, the amount of Co-MOF / TiO2 heterojunction composite photocatalyst added is 0.1~0.3 g / L, and the amount of PMS added is 0.2~0.4 g / L.

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