Metal covalent organic framework dimension isomer as well as preparation method and application thereof
By preparing the metal covalent organic framework dimensional isomers TFpb-1D MCOF and TFob-2D MCOF, the problem of low uranium reduction efficiency of existing photocatalysts in rare earth tailings waste liquid was solved, and efficient, rapid and stable uranyl removal effect was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-10
AI Technical Summary
Existing photocatalysts have low uranium reduction efficiency in treating rare earth tailings wastewater, and their stability and selectivity are insufficient in complex acidic environments and in the presence of high concentrations of competing ions, making it difficult to meet practical needs.
Metal covalent organic framework dimensional isomers TFpb-1D MCOF and TFob-2D MCOF were prepared by coordination metal induction strategy, and their band structure and adsorption catalytic activity were adjusted. The electron distribution of Cu in different coordination environments was used to improve the removal capacity of UO22+.
It achieves efficient, rapid, and stable uranyl removal, with good anti-interference performance and high selectivity, and is suitable for the photocatalytic reduction of U(VI) in rare earth tailings waste liquid.
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Figure CN121824880A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of materials chemistry technology, specifically relating to a metal covalent organic framework dimensional isomer, its preparation method, and its application. Background Technology
[0002] With the large-scale mining and utilization of rare earth resources, the separation and treatment of radioactive uranium associated with rare earth tailings wastewater has become a critical issue related to environmental safety and sustainable resource utilization. Rare earth minerals often coexist with radioactive elements such as uranium and thorium. During mineral processing and smelting, large quantities of complex, highly acidic wastewater rich in high concentrations and high mobility of hexavalent uranium (U(VI)) are generated. This wastewater possesses strong radioactivity and ecotoxicity, and direct discharge would pose a serious threat to water bodies, soil, and human health. Compared to soluble U(VI), tetravalent uranium (U(IV)) is easier to separate from water bodies through precipitation due to its low solubility and weak toxicity. Therefore, how to efficiently reduce U(VI) to U(IV) has become the core issue in the treatment of rare earth associated radioactive uranium. Traditional chemical reduction methods suffer from high costs and the potential for secondary pollution, while photocatalytic reduction technology, driven by solar energy, offers advantages such as green energy saving, no pollution, and sustainability, and is considered the most promising solution. However, the complex acidic environment, high concentration of competing ions (such as transition metals and rare earth metals) in actual wastewater, and the radioactivity of uranium itself place stringent requirements on the stability, selectivity, and anti-interference properties of photocatalytic materials. Existing photocatalysts (such as TiO2 and carbon nitride) generally suffer from problems such as narrow light absorption range, high carrier recombination rate, and insufficient surface active sites, resulting in reduction efficiencies that are difficult to meet practical needs.
[0003] Reticular chemistry, by assembling molecular building blocks into periodic solid-state materials (such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), has opened up new possibilities for developing advanced materials with customized structures and enhanced functions. The diversity of combinations of connecting nodes enables the formation of a rich library of networks with different topologies. As highly attractive prototype materials in reticular chemistry, COFs connect organic units in a spatially ordered manner through covalent bonds, constructing designable network structures, diverse topologies, porous frameworks, and pre-programmed physicochemical functions, thus finding wide applications in gas adsorption / separation, catalysis, optoelectronics, energy storage, and chemical sensing. One of the most significant features of COFs is their structural diversity—through rational molecular design, their dimensions can be precisely controlled, ranging from one-dimensional (1D) chain structures to extended two-dimensional (2D) layered structures. This dimensional control stems from the role of dynamic covalent chemistry during their assembly: the rational selection of symmetric building blocks and reversible bonding strategies jointly determine the spatial expansion law of the crystal network. However, current research on the synergistic effect of the regulation of symmetry building blocks and reversible covalent interactions in crystal structure formation remains extremely limited.
[0004] Currently reported COF materials are predominantly two-dimensional (2D). The periodic π-π interactions within their stacked, layered arrangement enable interlayer charge transfer, a structural advantage that endows 2D COF materials with uniform one-dimensional nanochannels, making them ideal candidates for molecular sieving and ion transport. In contrast, one-dimensional COFs possess a fundamentally different chain-like topology, exhibiting three core advantages: full exposure of catalytically active sites through a non-layered configuration, atomically precise edge microenvironments with unsaturated coordination, and unidirectional electron transport pathways formed along the framework backbone. Benefiting from anisotropic exciton migration and suppressed charge recombination, one-dimensional COFs demonstrate unique potential in photocatalysis. However, achieving dimensional control within a single crystalline framework presents significant challenges; traditional COF building blocks cannot generate true dimensional isomers (i.e., structurally differentiated COFs with the same molecular composition but different connection dimensions). Summary of the Invention
[0005] In view of this, the present invention provides a metal covalent organic framework dimensional isomer, its preparation method, and its application. By employing a coordination metal-induced strategy to modulate the linker structure, the metal covalent organic framework is transformed from linear to nonlinear, thus generating the first examples of dimensional isomers of MCOF, named TFpb-1D MCOF and TFob-2D MCOF. The introduction of the coordination metal Cu significantly improves the overall reducing power of the MCOF and modulates its band structure. The electron distribution of Cu in different coordination environments leads to the d-band center being closer to the Fermi level, thereby enhancing adsorption and catalytic activity. This makes TFpb-1D MCOF more effective against UO2. 2+ It can remove pollutants efficiently and has good application potential.
[0006] First, the present invention provides a metal covalent organic framework dimensional isomer, which is prepared by a catalytic reaction of a bipyridyl monomer, an aldehyde pyrene monomer, and copper acetate.
[0007] Preferably, the bipyridyl monomer is 6,6'-diamino-2,2'-bipyridyl monomer (o-bpy) or 4,4'-diamino-2,2'-bipyridyl monomer (p-bpy); the aldehyde pyrene monomer is 1,3,6,8-tetrakis(4-carboxylphenyl)pyrene (TFPPy); and the copper acetate is copper acetate monohydrate.
[0008] Secondly, this application provides a method for preparing a one-dimensional metal covalent organic framework dimensional isomer, wherein the metal covalent organic framework dimensional isomer is a one-dimensional metal covalent organic framework, and the specific preparation method is as follows: The 6,6'-diamino-2,2'-bipyridyl monomer, aldehyde pyrene monomer, copper acetate and mixed solvent were uniformly mixed and ultrasonically treated. Then, a catalyst was added, and the mixture was frozen, degassed and sealed. The reaction was then carried out at 120℃ for 72 h. Finally, the precipitate was washed and dried to obtain the one-dimensional MCOF material, named TFpb-1D MCOF.
[0009] Preferably, the molar ratio of the 6,6'-diamino-2,2'-bipyridyl monomer, the aldehyde pyrene monomer, and copper acetate is 2:1:1; the mixed solvent is a 1:1 volume ratio of o-dichlorobenzene (o-DCB) / ethanol (EtOH) mixed solution, and the amount of mixed solvent added is such that the concentration of the aldehyde pyrene monomer is 0.01-0.02 mmol / mL; the catalyst is an acetic acid solution with a concentration of 6 mol / L; and the molar ratio of the aldehyde pyrene monomer to the catalyst is 1:30-40.
[0010] Preferably, the ultrasonic treatment time is 15 min; the washing is performed sequentially with N,N-dimethylformamide, tetrahydrofuran and acetone; the drying is vacuum drying at 60°C for 12 h.
[0011] More preferably, the amount of the mixed solvent added is such that the concentration of the aldehyde pyrene monomer is 0.015 mmol / mL; and the molar ratio of the aldehyde pyrene monomer to the catalyst is 1:40.
[0012] In addition, the present invention also provides a method for preparing the metal covalent organic framework dimensional isomer, wherein the metal covalent organic framework dimensional isomer is a two-dimensional metal covalent organic framework, and the specific preparation method is as follows: Aldehyde pyrene monomer, copper acetate and o-dichlorobenzene were mixed and subjected to a first ultrasonic treatment. Then, 4,4'-diamino-2,2'-bipyridyl monomer, n-butanol (n-BuOH) and tetrahydrofuran (THF) were added and subjected to a second ultrasonic treatment. A catalyst was added, and the mixture was frozen, degassed and sealed. The mixture was then reacted at 120°C for 72 h. Finally, the precipitate was washed and dried to obtain the two-dimensional MCOF material, named TFob-2D MCOF.
[0013] Preferably, the molar ratio of the 4,4'-diamino-2,2'-bipyridyl monomer, the aldehyde pyrene monomer, and copper acetate is 2:1:2; the volume ratio of the o-dichlorobenzene, n-butanol, and tetrahydrofuran is 1:1:0.1; the total amount of o-dichlorobenzene, n-butanol, and tetrahydrofuran added is such that the concentration of the aldehyde pyrene monomer is 0.009-0.019 mmol / mL; the catalyst is p-toluenesulfonic acid with a concentration of 6 mol / L; and the molar ratio of the aldehyde pyrene monomer to the catalyst is 1:30-40.
[0014] Preferably, the first ultrasonic treatment lasts for 15 minutes, and the second ultrasonic treatment lasts for 5 minutes; the washing is performed sequentially with N,N-dimethylformamide, tetrahydrofuran, and acetone; and the drying is performed under vacuum at 60 °C for 12 hours.
[0015] More preferably, the amount of o-dichlorobenzene, n-butanol, and tetrahydrofuran added is such that the concentration of the aldehyde pyrene monomer is 0.014 mmol / mL; and the molar ratio of the aldehyde pyrene monomer to the catalyst is 1:40.
[0016] Finally, this invention also protects the application of the above-mentioned metal covalent organic framework dimensional isomers in the photocatalytic reduction of uranyl.
[0017] The specific steps are as follows: Adding the metal covalent organic framework dimensional isomer to UO2. 2+ In the solution, shake on a shaker and react under light, then filter.
[0018] Preferably, the UO2 2+ The solution pH is 1-5, UO2 2+The concentration range is 0-750 ppm; the shaking time of the shaker under light is 0-120 min; and the pore size of the microporous filter membrane is 0.22 μm.
[0019] More preferably, the UO2 2+ The solution pH is 4, UO2 2+ The concentration range is 200 ppm; the shaking time for light irradiation is 60 min.
[0020] Compared with the prior art, this invention discloses a metal covalent organic framework dimensional isomer, its preparation method, and its application, the advantages of which are: (1) The TFob-1D MCOF and TFpb-2D MCOF photocatalysts prepared by the method of the present invention have strong metal reduction centers and can remove uranium from rare earth tailings waste liquid rapidly, with stable cycle and large capacity.
[0021] (2) The TFob-1D MCOF and TFpb-2D MCOF photocatalysts prepared by the method of the present invention reveal the mechanism of photocatalytic reduction of uranyl by metal in different dimensional coordination environments.
[0022] (3) The TFob-1D MCOF and TFpb-2D MCOF photocatalysts prepared in this invention have strong photocatalytic reduction ability for U(VI), high efficiency and good selectivity. They are high-efficiency photocatalysts with good application prospects. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0024] Figure 1 A schematic diagram of the synthesis route of this invention.
[0025] Figure 2 The PXRD plot of TFob-1D MCOF in Embodiment 1 of this invention, wherein the thick curve is the experimental PXRD data and the thin curve is the PXRD result of the simulated AA and AB stacking models.
[0026] Figure 3 The PXRD plot of TFpb-2D MCOF in Example 1 of this invention, wherein the thick curve is the experimental PXRD data and the thin curve is the PXRD result of the simulated AA and AB stacking models.
[0027] Figure 4This is the FTIR image of TFob-1D MCOF in Embodiment 1 of the present invention.
[0028] Figure 5 This is the FTIR image of TFpb-2D MCOF in Embodiment 1 of the present invention.
[0029] Figure 6 These are TEM and HR-TEM images of the TFob-1D MCOF in Embodiment 1 of the present invention.
[0030] Figure 7 These are TEM and HR-TEM images of TFpb-2D MCOF in Example 1 of the present invention.
[0031] Figure 8 Example 1 of this invention describes the application of TFob-1D MCOF and TFpb-2D MCOF to UO2. 2+ pH optimization diagram for removal.
[0032] Figure 9 Example 1 of this invention describes the application of TFob-1D MCOF and TFpb-2D MCOF to UO2. 2+ Remove the isotherm plot.
[0033] Figure 10 Example 1 of this invention describes the application of TFob-1D MCOF and TFpb-2D MCOF to UO2. 2+ The removal kinetics diagram.
[0034] Figure 11 Example 1 of the application of this invention: TFob-1D MCOF for UO2 2+ The image with interference removed. Detailed Implementation
[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0036] Example 1 A method for preparing a one-dimensional metal covalent organic framework dimensional isomer, wherein the metal covalent organic framework dimensional isomer is a one-dimensional metal covalent organic framework: TFPPy (18.56 mg, 0.03 mmol), Cu(CH3COO)2·H2O (5.98 mg, 0.03 mmol), o-bpy (11.17 mg, 0.06 mmol), and o-DCB / EtOH (1:1; 2.0 mL) were added to a test tube and sonicated for 15 minutes. Then, 0.2 mL of acetic acid (6 M) was introduced, and the test tube was rapidly frozen in a liquid nitrogen bath. The tube was then thawed and degassed using three cryogenic pumps, and flame-sealed under vacuum. After heating to room temperature, the sealed tube was placed in an oven at 120°C and reacted for 72 h. The precipitate was collected by filtration, washed sequentially with DMF, THF, and acetone, and dried under vacuum at 60°C for 12 h to obtain a green solid, which was the one-dimensional MCOF material, named TFpb-1D MCOF.
[0037] Example 2 A method for preparing a two-dimensional metal covalent organic framework dimensional isomer, wherein the metal covalent organic framework dimensional isomer is a two-dimensional metal covalent organic framework: TFPPy (18.56 mg, 0.03 mmol), Cu(CH3COO)2·H2O (11.97 mg, 0.06 mmol), and o-DCB (1.0 mL) were added to a test tube and sonicated for 15 minutes. Then, p-bpy (11.17 mg, 0.06 mmol), n-BuOH (1.0 mL), and THF (0.1 mL) were added, and the mixture was sonicated for 5 minutes. 0.2 mL of p-toluenesulfonic acid (6 M) was introduced, and the test tube was rapidly frozen in a liquid nitrogen bath. The tube was then thawed and degassed using three cryogenic pumps, and flame-sealed under vacuum. After reaching room temperature, the sealed tube was placed in an oven at 120°C and reacted for 72 h. The precipitate was collected by filtration, washed sequentially with DMF, THF, and acetone, and dried under vacuum at 60°C for 12 h to obtain a green solid, which was the two-dimensional MCOF material, named TFpb-2D MCOF.
[0038] Test Example 1 The structures of the prepared TFob-1D MCOF and TFpb-2D MCOF were measured using powder X-ray diffraction (PXRD), revealing them to be highly crystalline covalent organic frameworks. The results are as follows: Figure 2 and Figure 3 The bolded black curves show the theoretical PXRD spectra of the COF under AA stacking conditions, which can be exported from the software Materials Studio. The experimentally measured PXRD spectra of TFob-1D MCOF and TFpb-2D MCOF powders match the characteristic peaks of the theoretical PXRD spectra, indicating that the TFob-1D MCOF and TFpb-2D MCOF materials have been successfully synthesized.
[0039] Figure 4 and 5 The images show HR-TEM images of TFob-1D MCOF and TFpb-2D MCOF prepared in Example 1 of this invention. Regular lattice fringes are observed in the HR-TEM images of TFob-1D MCOF and TFpb-2D MCOF.
[0040] Figure 6 and 7 The images show the FTIR spectra of TFob-1D MCOF and TFpb-2D MCOF prepared in Example 1 of this invention. In the FTIR spectra of TFob-1D MCOF and TFpb-2D MCOF, the NH(NH2) doublet disappears, and the peak at 1656 cm⁻¹ is also absent. -1 The presence of an absorption peak corresponding to the -C=N bond provides evidence for the formation of imine bonds.
[0041] Application Example 1 The TFob-1D MCOF and TFpb-2D MCOF materials prepared in the examples were applied to UO2. 2+ The specific steps for removing the verification are as follows: (1) UO2 of TFob-1D MCOF and TFpb-2D MCOF 2+ pH optimization for removal To determine the optimal pH for U(VI) recovery, the pH of the solution was adjusted to 1.0, 2.0, 3.0, 4.0, and 5.0 using hydrochloric acid or sodium hydroxide aqueous solution, respectively. 5.0 mg of the prepared TFob-1D MCOF and TFpb-2D MCOF adsorbents were weighed and placed in transparent glass bottles containing 15 mL of U(VI) solution (500 ppm concentration) at different pH values. After 1 hour, 1 mL of the suspension was taken to determine the residual U(VI) concentration in the solution. Results are shown below. Figure 8 This indicates that the adsorbent exhibits the highest removal capacity at a pH of 4. Subsequent studies on kinetics, adsorption isotherms, selectivity, and regeneration all adjusted the solution pH to 4.
[0042] (2) Adsorption isotherms of TFob-1D MCOF and TFpb-2D MCOF 8 mg of TFob-1D MCOF and TFpb-2D MCOF were added to 24 mL of UO2 containing different concentrations (0-750 ppm). 2+ The suspension was placed in a shaker and irradiated for 1 h, then filtered through a 0.22 μm microporous membrane. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the UO2 content in the filtrate. 2+The remaining concentration, the removal capacity at equilibrium (q) e mg g -1 The calculation formula is q e =(C o -C e ) / m×V. Where q e (mg g) -1 ) is the maximum adsorption capacity, C0 (mg / L) -1 ) and C e (mg L) -1 q represents the initial and equilibrium concentrations of uranyl ions, respectively. V (L) is the volume of the solution, and m (g) is the mass of the adsorbent. Experimental data were fitted using the Langmuir isotherm model: q e = q m bC e / (1+bC e ), where b is the Langmuir constant (L mg) -1 ), C e The equilibrium concentration of uranyl ions (mg / L) -1 ), q m Monolayer removal capacity (mg g) -1 ), q e To balance the removal capacity (mg g) -1 The effects of TFob-1D MCOF and TFpb-2D MCOF on UO2 were calculated. 2+ The adsorption capacity, the results are as follows Figure 9 TFob-1D MCOF and TFpb-2D MCOF on UO2 2+ The adsorption capacity varies with UO2 2+ The adsorption capacity of TFob-1D MCOF and TFpb-2D MCOF increases with increasing concentration until an adsorption equilibrium is reached. 2+ The maximum adsorption capacities were 1132.4 and 793.26 mg / g, respectively.
[0043] (3) Adsorption kinetics of TFob-1D MCOF and TFpb-2D MCOF Disperse 5 mg of TFob-1D MCOF and TFpb-2D MCOF in UO2 2+ The solution (15 mL, 200 ppm) was placed on a shaker and exposed to light for different times. The solution was then filtered through a 0.22 μm microporous membrane. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the UO2 content in the filtrate at different time points. 2+ The remaining concentration is used to calculate the removal capacity q at that time using the formula. t =(C o -C t) / m×V, where V is the volume of the solution (L), m is the mass of the photocatalyst used (g), and C o and C t These are the initial concentration and the concentration at a given time of uranyl, respectively (mg / L). -1 The experimental data were fitted using a pseudo-second-order dynamic model: t / q t =1 / K2q e 2 +t / q e , where q t and q e These represent the removal amounts (mg / g) at time t and at equilibrium (min). -1 K2 represents the pseudo-second-order rate constant (g mg). -1 min -1 The effects of TFob-1D MCOF and TFpb-2D MCOF on UO2 at that moment were calculated. 2+ The adsorption capacity, the results are as follows Figure 9 It can be seen that TFob-1D MCOF and TFpb-2D MCOF reach adsorption equilibrium within 60 min.
[0044] (4) Interference experiments of TFob-1D MCOF and TFpb-2D MCOF Add 5 mg of TFob-1D MCOF and TFpb-2D MCOF to 15 mL of solution containing 200 ppm metal ions and 50 ppm UO2. 2+ To evaluate the material's response to UO2 in solution. 2+ The anti-interference experiment was conducted by measuring UO2 in the filtrate using inductively coupled plasma mass spectrometry. 2+ The concentrations of TFob-1D MCOF and TFpb-2D MCOF under coexisting ion conditions were calculated to determine their effects on UO2. 2+ The adsorption amount, the results are as follows Figure 10 This indicates that TFob-1D MCOF and TFpb-2D MCOF have strong anti-interference performance.
[0045] As can be seen from the above, the TFob-1D MCOF and TFpb-2D MCOF prepared by the method of the present invention have a positive effect on UO2. 2+ It possesses a large removal capacity and rapid removal kinetics, and exhibits good anti-interference performance, making it suitable for removing UO2 from rare earth tailings wastewater. 2+ The removal of.
[0046] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A metal covalent organic framework dimensional isomer, characterized in that, The metal covalent organic framework dimensional isomers were prepared by a catalytic reaction of a bipyridyl monomer, an aldehyde pyrene monomer, and copper acetate.
2. The metal covalent organic framework dimensional isomer according to claim 1, characterized in that, The bipyridyl monomer is a 6,6'-diamino-2,2'-bipyridyl monomer or a 4,4'-diamino-2,2'-bipyridyl monomer; The aldehyde pyrene monomer is 1,3,6,8-tetrakis(4-carboxymethylphenyl)pyrene; The copper acetate is copper acetate monohydrate.
3. A method for preparing the metal covalent organic framework dimensional isomer as described in claim 2, characterized in that, The metal covalent organic framework dimensional isomer is a one-dimensional metal covalent organic framework, and its specific preparation method is as follows: The 6,6'-diamino-2,2'-bipyridyl monomer, aldehyde pyrene monomer, copper acetate and mixed solvent were uniformly mixed and ultrasonically treated. Then, a catalyst was added, and the mixture was frozen, degassed and sealed. The reaction was then carried out at 120℃ for 72 h. Finally, the precipitate was washed and dried to obtain the one-dimensional MCOF material, named TFpb-1D MCOF.
4. The preparation method according to claim 3, characterized in that, The molar ratio of the 6,6'-diamino-2,2'-bipyridyl monomer, the aldehyde pyrene monomer, and the copper acetate is 2:1:1; The mixed solvent is a 1:1 volume ratio o-dichlorobenzene / ethanol mixed solution, and the amount of mixed solvent added is such that the concentration of aldehyde pyrene monomer is 0.01-0.02 mmol / mL; The catalyst is an acetic acid solution with a concentration of 6 mol / L; the molar ratio of the aldehyde pyrene monomer to the catalyst is 1:30-40.
5. The preparation method according to claim 3, characterized in that, The ultrasonic treatment time is 15 min; the washing is performed sequentially with N,N-dimethylformamide, tetrahydrofuran and acetone; the drying is vacuum drying at 60℃ for 12 h.
6. A method for preparing the metal covalent organic framework dimensional isomer as described in claim 2, characterized in that, The metal covalent organic framework dimensional isomer is a two-dimensional metal covalent organic framework, and its specific preparation method is as follows: Aldehyde pyrene monomer, copper acetate and o-dichlorobenzene were mixed and subjected to a first ultrasonic treatment. Then, 4,4'-diamino-2,2'-bipyridyl monomer, n-butanol and tetrahydrofuran were added and subjected to a second ultrasonic treatment. A catalyst was added, and the mixture was frozen, degassed and sealed. The mixture was then reacted at 120°C for 72 h. Finally, the precipitate was washed and dried to obtain the two-dimensional MCOF material, named TFob-2D MCOF.
7. The preparation method according to claim 6, characterized in that, The molar ratio of the 4,4'-diamino-2,2'-bipyridyl monomer, the aldehyde pyrene monomer, and the copper acetate is 2:1:
2. The volume ratio of o-dichlorobenzene, n-butanol, and tetrahydrofuran is 1:1:0.1, and the total amount of o-dichlorobenzene, n-butanol, and tetrahydrofuran added is such that the concentration of aldehyde pyrene monomer is 0.009-0.019 mmol / mL. The catalyst is p-toluenesulfonic acid with a concentration of 6 mol / L; the molar ratio of the aldehyde pyrene monomer to the catalyst is 1:30-40.
8. The preparation method according to claim 6, characterized in that, The first ultrasonic treatment lasted 15 minutes, and the second ultrasonic treatment lasted 5 minutes; the washing was carried out sequentially with N,N-dimethylformamide, tetrahydrofuran, and acetone; the drying was carried out under vacuum at 60 °C for 12 h.
9. The application of the metal covalent organic framework dimensional isomer according to any one of claims 1-2 or the metal covalent organic framework dimensional isomer prepared by the preparation method according to any one of claims 3-8 in the photocatalytic reduction of uranyl.
10. The application according to claim 9, characterized in that, The specific steps are as follows: Adding the metal covalent organic framework dimensional isomer to UO2. 2+ In the solution, shake on a shaker and react under light, then filter.