A porous metal-organic framework-derived material for adsorbing rare earth metal ions, its preparation method and application

Abstract

The present invention discloses a porous metal-organic framework-derived material for adsorbing rare earth metal ions, its preparation method and application, belonging to the technical field of rare earth metal ion adsorption and removal. The porous metal-organic framework-derived material for adsorbing rare earth metal ions includes a porous metal-organic framework and organic small molecules grafted on the porous metal-organic framework. The porous metal-organic framework-derived material of the present invention has excellent rare earth metal ion adsorption properties. Therefore, the porous metal-organic framework-derived material can be constructed into a micro-trapping device for application in the adsorption and removal of rare earth metal ions in water environment.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth metal ion adsorption and removal, and particularly to a porous metal-organic framework-derived material for adsorbing rare earth metal ions, a preparation method thereof, and an application thereof. Background Art

[0002] Fresh water resources are the basis for human survival and development. In order to solve the problem of rare earth metal ion pollution caused by the discharge of industrial wastewater and nuclear wastewater, methods including removal, fixation, and recovery have been developed, such as adsorption, membrane separation, precipitation, electrochemical treatment, ion exchange, and biological methods. Among them, the adsorption method has a good effect on the treatment of rare earth metal ions in the water environment. The materials used are green, environmentally friendly, low-cost, and have flexible designability. It is currently the most commonly used method by scientific researchers to remove rare earth metal ions from water bodies. However, traditional adsorbents have problems such as poor adsorption effect, single removal target, and difficult recovery. Therefore, the development of new adsorbents with multiple adsorption sites, strong universality, and easy recovery performance is of great significance for dealing with the rare earth metal ion pollution problem caused by industrial wastewater and nuclear wastewater. Summary of the Invention

[0003] The object of the present invention is to provide a porous metal-organic framework-derived material for adsorbing rare earth metal ions, a preparation method thereof, and an application thereof, so as to solve the problems existing in the above-mentioned prior art. The porous metal-organic framework-derived material designed by the present invention can simultaneously remove almost all lanthanide rare earth elements, solving the problems of single adsorption target, poor recovery ability, and few adsorption sites of existing adsorption materials.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] One of the technical solutions of the present invention: A porous metal-organic framework-derived material for adsorbing rare earth metal ions, including a porous metal-organic framework and an organic small molecule grafted (grafting specifically refers to replacing -COOH on the metal-organic framework with a group on the organic small molecule) on the porous metal-organic framework.

[0006] Further, the porous metal-organic framework is MOF 808 (MOF 808 has a large pore size and a large specific surface area, and -COOH on the Zr6 cluster (zirconium oxygen cluster) is easily replaced by an organic small molecule with -COOH to achieve the functionalization of MOF 808).

[0007] Further, the organic small molecule is 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA). One molecule of PBTCA has 3 -COOH groups, which can replace the -COOH groups on the Zr6 cluster to achieve the grafting purpose. Moreover, PBTCA contains abundant unsaturated coordination sites and can well adsorb rare earth metal ions.

[0008] Further, the preparation method of the MOF 808 includes: dissolving 1,3,5-benzenetricarboxylic acid and a Zr source in a mixed solution of DMF (N,N-dimethylformamide) and formic acid, heating for reaction, then centrifuging, washing, and drying to obtain the MOF 808.

[0009] Further, the Zr source is ZrOCl 2 ·8H 2 O. The volume ratio of DMF to formic acid in the mixed solution is 1:1; the dosage ratio of 1,3,5-benzenetricarboxylic acid, ZrOCl 2 ·8H 2 O, and the mixed solution of DMF and formic acid is 0.21 g:0.97 g:60 mL.

[0010] Further, the temperature of the heating reaction is 100 °C and the time is 24 h.

[0011] Further, the specific operation of the washing is: washing the precipitate collected by centrifugation three times with DMF within 24 h, and then washing three times with acetone within 24 h.

[0012] Further, the specific surface area of the MOF 808 is 1183.94 m 2 / g, and the average pore size is 1.8 nm.

[0013] The second technical solution of the present invention: The preparation method of the above-mentioned porous metal-organic framework-derived material for adsorbing rare earth metal ions includes the following steps:

[0014] Dripping the organic small molecule into the dispersion of the porous metal-organic framework, and continuously stirring at room temperature (during the stirring process, the organic small molecule is grafted into the porous metal-organic framework) to obtain the porous metal-organic framework-derived material for adsorbing rare earth metal ions (or called the porous metal-organic framework-derived material grafted with an organic small molecule, abbreviated as MOF 808-PBTCA).

[0015] Further, the mass ratio of the organic small molecule to the porous metal-organic framework is 3:100.

[0016] Further, the time of the continuous stirring is 20 h.

[0017] Further, after the continuous stirring is completed, it also includes centrifugally collecting the powder, soaking the collected powder in ultrapure water and washing it three times within 24 hours, and then washing it 3 times with acetone within 24 hours.

[0018] The third technical solution of the present invention: Application of the above-mentioned porous metal-organic framework-derived material for adsorbing rare earth metal ions in the adsorption of rare earth metal ions.

[0019] Further, the rare earth metal ions are lanthanide rare earth metal ions.

[0020] In the present invention, by grafting organic small molecules into MOF, a porous metal-organic framework-derived material grafted with organic small molecules is obtained. This porous metal-organic framework-derived material is a novel rare earth metal ion adsorbent, and this porous metal-organic framework-derived material can be constructed into a micro-trapping device for the adsorption and removal of rare earth metal ions in the water environment. It has the characteristics of many adsorption sites, strong universality, and easy recovery. By utilizing the interaction between the organic small molecules grafted on the MOF and the rare earth metal ions, efficient removal of rare earth ions in the water environment can be achieved.

[0021] The porous metal-organic framework-derived material grafted with organic small molecules not only retains the original characteristics of the porous metal-organic framework such as large specific surface area, high porosity, and controllable structure, but also enriches abundant adsorption sites in the pores, and can be used in some fields such as the capture and transportation of substances, adsorption separation, and storage and release.

[0022] The present invention discloses the following technical effects:

[0023] (1) The porous metal-organic framework-derived material for adsorbing rare earth metal ions prepared in the present invention (porous metal-organic framework-derived material grafted with organic small molecules) has strong rare earth metal ion adsorption performance and can achieve rapid adsorption of rare earth metal ions at room temperature.

[0024] (2) The porous metal-organic framework-derived material for adsorbing rare earth metal ions prepared in the present invention has the advantages of high crystallinity, complete morphology, porous structure, large specific surface area, fast adsorption rate, large adsorption capacity, good stability (the structure will not be damaged after adsorbing rare earth elements), and strong anti-interference ability, and can achieve the adsorption and removal of rare earth metal ions in industrial wastewater and nuclear wastewater.

[0025] (3) When the porous metal-organic framework-derived material for adsorbing rare earth metal ions prepared in the present invention adsorbs rare earth metal ions in water, the adsorption equilibrium can be reached in 15 minutes, and rapid adsorption can also be achieved in a low-concentration rare earth metal ion environment.

[0026] (4) The synthetic route of the present invention is simple and feasible, the reaction conditions are mild and controllable, the product yield is high, the stability is good, and the cost is low, making it suitable for large-scale use. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is the TEM and EDS element distribution diagrams of the raw material MOF 808 in the present invention;

[0029] Figure 2 It is the TEM and EDS element distribution diagrams of MOF 808-PBTCA prepared in Example 1 of the present invention;

[0030] Figure 3 It is the TEM and EDS element distribution diagrams of MOF 808-PBTCA@Ce obtained in Application Example 1 of the present invention;

[0031] Figure 4 It is the TEM and EDS element distribution diagrams of MOF 808-PBTCA@Eu obtained in Application Example 2 of the present invention;

[0032] Figure 5 It is the TEM and EDS element distribution diagrams of MOF 808-PBTCA@Nd obtained in Application Example 3 of the present invention;

[0033] Figure 6 It is the XRD diagrams of the raw material MOF 808, MOF 808-PBTCA prepared in Example 1, and MOF 808-PBTCA@Ce, MOF 808-PBTCA@Eu, MOF 808-PBTCA@Nd after adsorbing rare earth metal ions in Application Examples 1-3;

[0034] Figure 7 It is the FT-IR diagrams of the raw material MOF 808, MOF 808-PBTCA prepared in Example 1, and MOF 808-PBTCA@Ce, MOF 808-PBTCA@Eu, MOF 808-PBTCA@Nd after adsorbing rare earth metal ions in Application Examples 1-3;

[0035] Figure 8 It is the nuclear magnetic resonance hydrogen spectrum diagrams of the raw material MOF 808 (a) and MOF 808-PBTCA (b) prepared in Example 1;

[0036] Figure 9 FT-IR spectra of ZIF 8 prepared in Comparative Example 2 and ZIF 8 grafted with PBTCA;

[0037] Figure 10 N adsorption-desorption isotherms (a) and pore size distribution curves (b) of raw material MOF 808, MOF 808-PBTCA prepared in Example 1, and MOF 808-PBTCA@Ce, MOF 808-PBTCA@Eu, MOF 808-PBTCA@Nd after adsorbing rare earth metal ions in Application Examples 1-3; 2 Adsorption-desorption isotherms (a) and pore size distribution curves (b);

[0038] Figure 11 Relationship diagram of adsorption efficiency and adsorption time of MOF 808-PBTCA prepared in Example 1 during the adsorption of Ce, Eu, and Nd;

[0039] Figure 12 Adsorption efficiency diagram of MOF 808-PBTCA prepared in Example 1 in a mixed system of transition metal ions and rare earth ions. Detailed Description of the Invention

[0040] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be construed as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0042] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0043] Without departing from the scope or spirit of the present invention, various modifications and variations can be made to the specific embodiments of the present invention's specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.

[0044] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0045] In the specific embodiments of the present invention, the calculation method of the yield is: the mass of the dried product / the sum of the masses of the raw materials × 100%.

[0046] In the specific embodiments of the present invention, the calculation method of the adsorption efficiency of the adsorbent material for rare earth metal ions is: the difference in the content of rare earth ions in the solution before and after adsorption / the content of rare earth ions in the solution before adsorption × 100%.

[0047] In the specific embodiments of the present invention, the calculation method of the adsorption capacity of the adsorbent material for rare earth metal ions is: the difference in the content of rare earth ions in the solution before and after adsorption / the amount of the adsorbent material used × 100%.

[0048] In the specific embodiments of the present invention, the room temperature specifically refers to 20 - 30 °C.

[0049] In the specific embodiments of the present invention, the preparation method of MOF 808 used is as follows: In a 100 mL flask, 1,3,5-benzenetricarboxylic acid (0.21 g) and ZrOCl 2 ·8H 2 O (0.97 g, purity 98%) are dissolved in a mixed solution of 60 mL of DMF and formic acid (30 mL DMF + 30 mL formic acid). The flask is sealed and heated in a constant temperature oven at 100 °C for 24 h. The white powder is collected by centrifugation (8000 rpm, 3 min), washed three times with DMF within 24 h, then washed three times with acetone within 24 h, and finally dried in a vacuum furnace at 30 °C to obtain MOF 808. The TEM and EDS element distribution maps of the prepared MOF 808 are shown in Figure 1 , the XRD pattern is shown in Figure 6 , and the FT-IR pattern is shown in Figure 7 .

[0050] All raw materials other than MOF 808 are ordinary commercially available products.

[0051] Example 1

[0052] A preparation method of a porous metal-organic framework-derived material, the steps are as follows:

[0053] (1) Weigh 50 mg of MOF 808 and add it to 50 mL of ultrapure water. Sonicate for 5 min to evenly disperse MOF 808 and obtain a dispersion of MOF 808.

[0054] (2) Add 1.5 mg of PBTCA to the dispersion of MOF 808 obtained in step (1). Continuously stir at room temperature for 20 h, centrifuge to collect the powder, soak the collected powder in ultrapure water and wash it three times within 24 h, then wash it 3 times with acetone within 24 h, and dry it to obtain a porous metal-organic framework-derived material grafted with PBTCA (MOF 808-PBTCA). MOF 808-PBTCA is a white powder, with a yield of 97.4% and a purity of 99%.

[0055] Application Example 1

[0056] Weigh 10 mg of CeCl 3 10 mg, dissolve it in 10 mL of ultrapure water to obtain a CeCl 3 solution with a concentration of 1 mg / mL (repeat the above process to prepare two CeCl 3 solutions with the same concentration and volume, and use inductively coupled plasma to detect the content of Ce 3+ in the solution); Weigh 20 mg of MOF 808-PBTCA prepared in Example 1 and 20 mg of the raw material MOF 808 (as a control) and disperse them into the above two CeCl 3 solutions respectively. Stir at room temperature for 20 min, centrifuge and filter to obtain the supernatant and the residue (the residue in the group with MOF 808-PBTCA added is MOF 808-PBTCA adsorbed with Ce 3+ , denoted as MOF 808-PBTCA@Ce). Take the supernatant in the group with MOF 808-PBTCA added and the supernatant in the group with MOF 808 added, and use inductively coupled plasma (ICP-AES) to detect the content of Ce 3+ in the supernatant. According to the content of Ce 3+ in the supernatant after adsorption and the content of Ce 3+ in the solution before adsorption, as well as the dosage of MOF 808-PBTCA or MOF 808, calculate that the adsorption amounts of MOF 808-PBTCA and MOF 808 for Ce 3+ are 496 mg / g and 115.5 mg / g respectively; the adsorption efficiencies are 99.2% and 23.1% respectively. It shows that the MOF 808-PBTCA prepared in Example 1 has good adsorption effect on Ce 3+ .

[0057] Application Example 2

[0058] Weigh Eu(NO 3) 3 10 mg was dissolved in 10 mL of ultrapure water to obtain a Eu(NO 3 ) 3 solution (2 portions); 20 mg of MOF 808-PBTCA prepared in Example 1 and 20 mg of raw material MOF 808 (as a control) were separately dispersed into the above two portions of Eu(NO 3 ) 3 solutions, stirred at room temperature for 20 min, and centrifuged and filtered to obtain supernatant and residue (the residue of the group added with MOF 808-PBTCA was MOF 808-PBTCA adsorbed with Eu 3+ , denoted as MOF 808-PBTCA@Eu). The supernatant of the group added with MOF 808-PBTCA and the supernatant of the group added with MOF 808 were taken, and the content of Eu 3+ in the supernatant was detected by inductively coupled plasma. According to the content of Eu 3+ in the supernatant after adsorption and the content of Eu 3+ in the solution before adsorption and the dosage of MOF 808-PBTCA or MOF 808, the adsorption amounts of MOF 808-PBTCA and MOF 808 for Eu 3+ were calculated to be 491.5 mg / g and 113 mg / g respectively; the adsorption efficiencies were 98.3% and 22.6% respectively. It shows that the MOF 808-PBTCA prepared in Example 1 has good adsorption effect on Eu 3+ .

[0059] Application Example 3

[0060] Weigh 10 mg of Nd(NO 3 ) 3 , dissolve it in 10 mL of ultrapure water to obtain a Nd(NO 3 ) 3 solution (2 portions); 20 mg of MOF 808-PBTCA prepared in Example 1 and 20 mg of raw material MOF 808 (as a control) were separately dispersed into the above two portions of Nd(NO 3 ) 3 solutions, stirred at room temperature for 20 min, and centrifuged and filtered to obtain supernatant and residue (the residue of the group added with MOF 808-PBTCA was MOF 808-PBTCA adsorbed with Nd 3+ , denoted as MOF 808-PBTCA@Nd). The supernatant of the group added with MOF 808-PBTCA and the supernatant of the group added with MOF 808 were taken, and the content of Nd 3+ in the supernatant was detected by inductively coupled plasma. According to the content of Nd 3+The content of Nd in the solution before adsorption 3+ The adsorption amounts of Nd by MOF 808-PBTCA and MOF 808 were calculated based on the content of Nd in the solution before adsorption and the dosages of MOF 808-PBTCA or MOF 808, and they were 494.5 mg / g and 109.5 mg / g respectively; the adsorption efficiencies were 98.9% and 21.9% respectively. It shows that the MOF 808-PBTCA prepared in Example 1 has good adsorption effect on Nd 3+ 3+

[0061] Application Example 4

[0062] Weigh 10 mg each of CeCl 3 , Eu(NO 3 ) 3 , Nd(NO 3 ) 3 , La(NO 3 ) 3 , Pr(NO 3 ) 3 , Sm(NO 3 ) 3 , Gd(NO 3 ) 3 , Tb(NO 3 ) 3 , Dy(NO 3 ) 3 , Ho(NO 3 ) 3 , Er(NO 3 ) 3 and Yb(NO 3 ) 3 , dissolve them in 20 mL of ultrapure water to obtain a mixed solution with a concentration of 0.5 mg / mL for each rare earth metal salt (repeat the above process to prepare two equal-concentration and equal-volume mixed solutions, and detect the content of each rare earth metal ion in the mixed solution by inductively coupled plasma); weigh 20 mg of the MOF808-PBTCA prepared in Example 1 and 20 mg of the raw material MOF 808 (as a control) and disperse them into the above two mixed solutions respectively, stir at room temperature for 20 min, and centrifuge and filter to obtain the supernatant and the residue. Take the supernatant of the group with MOF 808-PBTCA added and the supernatant of the group with MOF 808 added, and detect the content of each rare earth metal ion in the supernatant by inductively coupled plasma. Calculate the adsorption efficiencies of MOF 808-PBTCA and MOF 808 for different rare earth metal ions in the mixed solution according to the content of each rare earth metal ion in the supernatant after adsorption and the content of each rare earth metal ion in the mixed solution before adsorption. The results are shown in Table 1

[0063] Table 1 ​​

[0064]

[0065]

[0066] As can be seen from Table 1, the adsorption efficiency of MOF 808 for rare earth metal ions at low concentrations (the concentration of rare earth metal salts is 0.5 mg / mL) remains at about 20%, while the adsorption efficiency of MOF 808-PBTCA prepared in Example 1 for rare earth metal ions at low concentrations (the concentration of rare earth metal salts is 0.5 mg / mL) can reach over 97%. After grafting PBTCA, the adsorption efficiency of MOF 808 for rare earth metal ions is greatly improved, indicating that the phosphate group of PBTCA plays an important role in the adsorption of rare earth metal ions.

[0067] Comparative Example 1

[0068] A preparation method of a porous metal-organic framework-derived material is as follows:

[0069] (1) Weigh 50 mg of MOF 808 and add it to 50 mL of ultrapure water. Sonicate for 5 min to disperse MOF 808 evenly, obtaining a dispersion of MOF 808.

[0070] (2) Add 1.2 mg of PBTCA to the dispersion of MOF 808 obtained in step (1). Continuously stir at room temperature for 20 h, centrifuge to collect the powder, soak the collected powder in ultrapure water and wash it three times within 24 h, then wash it 3 times with acetone within 24 h, and dry it to obtain the porous metal-organic framework-derived material grafted with PBTCA (MOF 808-PBTCA). MOF 808-PBTCA is a white powder with a yield of 98% and a purity of 97%.

[0071] Comparative Example 2

[0072] A preparation method of a porous metal-organic framework-derived material is as follows:

[0073] (1) Weigh 50 mg of MOF 808 and add it to 50 mL of ultrapure water. Sonicate for 5 min to disperse MOF 808 evenly, obtaining a dispersion of MOF 808.

[0074] (2) Add 2 mg of PBTCA to the dispersion of MOF 808 obtained in step (1), continuously stir at room temperature for 20 h, centrifuge to collect the powder, soak the collected powder in ultrapure water and wash it three times within 24 h, then wash it 3 times with acetone within 24 h, and dry it to obtain a porous metal-organic framework-derived material grafted with PBTCA (MOF 808-PBTCA). MOF 808-PBTCA is a white powder, with a yield of 97.5% and a purity of 94%.

[0075] Comparative Example 3

[0076] Same as Example 1, except that MOF 808 is replaced with an equal mass of ZIF 8 to obtain PBTCA-grafted ZIF8.

[0077] The above ZIF 8 was prepared by sequentially adding 0.3 g of zinc acetate and 1.12 g of 2-methylimidazole to 20 mL of ultrapure water and stirring at room temperature for 24 h.

[0078] Comparative Example 4

[0079] Same as Example 1, except that PBTCA is replaced with an equal mass of 2-hydroxyphosphonoacetic acid (HPAA) to obtain 2-hydroxyphosphonoacetic acid-grafted MOF 808-HPAA.

[0080] Comparative Application Example 1

[0081] Weigh 10 mg each of CeCl 3 , Eu(NO 3 ) 3 , Nd(NO 3 ) 3 , and dissolve them separately in 10 mL of ultrapure water to obtain CeCl 3 solution, Eu(NO 3 ) 3 solution, and Nd(NO 3 ) 3 solution with a concentration of 1 mg / mL each; separately disperse 20 mg of MOF 808-PBTCA prepared in Comparative Example 1 into the above CeCl 3 solution, Eu(NO 3 ) 3 solution, and Nd(NO 3 ) 3 solution, stir at room temperature for 20 min, and centrifuge and filter to obtain the supernatant and the residue. Take three groups of supernatants and use inductively coupled plasma to detect the content of Ce 3+ , Eu 3+ , or Nd 3+ in the supernatant. According to the content of Ce 3+ , Eu 3+or Nd 3+ content and Ce in the solution before adsorption 3+ Eu 3+ or Nd 3+ The adsorption amounts of Ce 3+ Eu 3+ and Nd 3+ by the MOF 808-PBTCA prepared in Comparative Example 1 were calculated to be 475.9 mg / g, 435.3 mg / g and 421.8 mg / g respectively; the adsorption efficiencies were 95.18%, 87.06% and 84.36% respectively.

[0082] Comparative Application Example 2

[0083] Same as Comparative Application Example 1, the difference is only that the MOF 808-PBTCA prepared in Comparative Example 1 is replaced by the MOF 808-PBTCA prepared in Comparative Example 2. The adsorption amounts of Ce 3+ Eu 3+ and Nd 3+ by the MOF 808-PBTCA prepared in Comparative Example 2 were calculated to be 493.7 mg / g, 487.5 mg / g and 426.3 mg / g respectively; the adsorption efficiencies were 98.74%, 97.5% and 85.26% respectively.

[0084] Comparative Application Example 3

[0085] Same as Comparative Application Example 1, the difference is only that the MOF 808-PBTCA prepared in Comparative Example 1 is replaced by the MOF 808-HPAA prepared in Comparative Example 4. The adsorption amounts of Ce 3+ Eu 3+ and Nd 3+ by the MOF 808-HPAA prepared in Comparative Example 4 were calculated to be 242.7 mg / g, 153.6 mg / g and 171.8 mg / g respectively; the adsorption efficiencies were 48.54%, 30.72% and 34.36% respectively.

[0086] Effect Example 1

[0087] Figure 1 are the TEM and EDS element distribution maps of the raw material MOF 808; Figure 2 are the TEM and EDS element distribution maps of the MOF 808-PBTCA prepared in Example 1; Figure 3 are the TEM and EDS element distribution maps of the MOF 808-PBTCA@Ce obtained in Application Example 1; Figure 4 are the TEM and EDS element distribution maps of the MOF 808-PBTCA@Eu obtained in Application Example 2; Figure 5TEM and EDS elemental distribution maps of MOF808-PBTCA@Nd obtained in Application Example 3.

[0088] As can be seen from Figure 1 , MOF 808 has a regular octahedron configuration, and the elements such as Zr, O, and C are evenly distributed; as can be seen from Figure 2 , after being grafted with the small molecule PBTCA, MOF 808 still maintains the original regular octahedron configuration of MOF 808, and the P element in PBTCA and the elements such as Zr, O, and C contained in MOF 808 are evenly distributed, indicating that PBTCA has been successfully grafted onto MOF808; as can be seen from Figure 3 , after adsorbing the rare earth element Ce, MOF 808-PBTCA still maintains the original regular octahedron configuration of MOF 808, and the adsorbed rare earth element Ce is evenly distributed on the surface of MOF 808-PBTCA; as can be seen from Figure 4 , after adsorbing the rare earth element Eu, MOF 808-PBTCA still maintains the original regular octahedron configuration of MOF 808, and the adsorbed rare earth element Eu is evenly distributed on the surface of MOF 808-PBTCA; as can be seen from Figure 5 , after adsorbing the rare earth element Nd, MOF 808-PBTCA still maintains the original regular octahedron configuration of MOF 808, and the adsorbed rare earth element Nd is evenly distributed on the surface of MOF 808-PBTCA.

[0089] After digesting the MOF 808-PBTCA prepared in Example 1, the contents of Zr and P were measured by inductively coupled plasma. The Zr content derived from MOF 808 was 13.7 mg / g, and the P content derived from PBTCA was 2.16 mg / g. The molar ratio of Zr to P in MOF 808-PBTCA was 2:1.

[0090] Effect Example 2

[0091] Figure 6 XRD (X-ray powder diffraction) patterns of the raw material MOF 808, MOF 808-PBTCA prepared in Example 1, and MOF 808-PBTCA@Ce, MOF 808-PBTCA@Eu, MOF 808-PBTCA@Nd after adsorbing rare earth metal ions in Application Examples 1-3; Figure 7 FT-IR (Fourier transform infrared spectroscopy) patterns of the raw material MOF 808, MOF 808-PBTCA prepared in Example 1, and MOF 808-PBTCA@Ce, MOF 808-PBTCA@Eu, MOF 808-PBTCA@Nd after adsorbing rare earth metal ions in Application Examples 1-3; Figure 81H NMR spectra of starting material MOF 808 (a) and MOF 808-PBTCA prepared in Example 1 (b); Figure 9 FT-IR spectra of ZIF 8 prepared in Comparative Example 2 and ZIF 8 grafted with PBTCA.

[0092] As can be seen from Figure 6 , after grafting MOF 808 with small molecule PBTCA, its XRD is consistent with that of MOF 808, indicating that grafting PBTCA onto MOF 808 does not destroy the structure of MOF 808; moreover, the structure of MOF 808-PBTCA is still not destroyed after adsorbing rare earth elements Ce, Eu, and Nd; as can be seen from Figure 7 , after grafting MOF 808 with small molecule PBTCA, bending and stretching vibrations of the phosphorus-oxygen double bond (-P=O) in the phosphorus group appear at 1060 cm -1 and 1230 cm -1 , and a stretching vibration peak of saturated carbonyl (C=O) appears at 1700 cm -1 . The above results prove that PBTCA has been successfully grafted into MOF-808; as can be seen from Figure 8 , the peak of hydrogen in formic acid at 8.02 ppm in MOF 808 completely disappears in MOF 808-PBTCA, and new signal peaks corresponding to different hydrogens of -CH- in PBTCA appear at 2.1 ppm and 3.0 ppm in MOF 808-PBTCA, indicating that the formic acid ligands on the Zr6 cluster are almost completely replaced by PBTCA molecules; as can be seen from Figure 9 , there are no obvious changes in the FT-IR spectra of ZIF 8 and ZIF 8 grafted with PBTCA, and no characteristic peaks of the functional groups in PBTCA appear, indicating that PBTCA has not been successfully grafted onto ZIF 8.

[0093] Effect Example 3

[0094] The specific surface areas and pore sizes of starting material MOF 808, MOF808-PBTCA prepared in Example 1, and MOF 808-PBTCA@Ce, MOF 808-PBTCA@Eu, and MOF 808-PBTCA@Nd after adsorbing rare earth metal ions in Application Examples 1-3 were tested by the Brunauer Emmett Teller (BET) method, and the results are as shown in Figure 10 , where a is the N 2 adsorption-desorption isotherm and b is the pore size distribution diagram.

[0095] As can be seen from Figure 10It can be obtained that the specific surface area and pore size of MOF 808, MOF 808-PBTCA, and MOF 808-PBTCA after adsorbing rare earth elements are gradually decreasing. The following is the main distribution of the specific surface area and pore size. Specific surface area: MOF 808: 1183.94 m 2 / g, MOF 808-PBTCA: 781.64 m 2 / g; MOF 808-PBTCA@Ce: 612.48 m 2 / g; MOF808-PBTCA@Eu: 673.60 m 2 / g; 808-PBTCA@Nd: 684.81 m 2 / g. Average pore size: MOF 808: about 1.8 nm, MOF 808-PBTCA: about 1.3 nm; MOF 808-PBTCA@Ce, MOF 808-PBTCA@Eu, 808-PBTCA@Nd are all distributed around 1.0 nm. This indicates that the porous structure of MOF 808 can provide a good carrier for the adsorption of rare earth metal ions.

[0096] Based on the results of Comparative Example 2 and Comparative Example 3, it can be known that only by grafting PBTCA onto MOF808 with a large specific surface area and porosity can a better adsorption effect on rare earth metal ions be achieved.

[0097] Comparative Example 4

[0098] The influence of adsorption time on the adsorption efficiency was detected by inductively coupled plasma. The specific operation was as follows: Weigh 10 mg each of CeCl 3 , Eu(NO 3 ) 3 , Nd(NO 3 ) 3 , and dissolve them separately in 10 mL of ultrapure water to obtain CeCl 3 solution, Eu(NO 3 ) 3 solution, and Nd(NO 3 ) 3 solution with a concentration of 1 mg / mL each; Disperse 20 mg of MOF 808-PBTCA prepared in Example 1 into the above CeCl 3 solution, Eu(NO 3 ) 3 solution, and Nd(NO 3 ) 3 solution respectively, stir at room temperature, and filter and transfer the supernatant at fixed intervals. Use inductively coupled plasma to detect Ce 3+ , Eu 3+ or Nd in the taken supernatant.3+ The content was used to calculate the corresponding adsorption efficiency respectively. The results are as Figure 11 shown. MOF 808-PBTCA can reach the adsorption equilibrium in about 15 min when adsorbing Ce, Eu, and Nd.

[0099] The adsorption efficiency of MOF 808-PBTCA prepared in Example 1 for each ion in the mixed system of transition metal ions and rare earth ions was detected by inductively coupled plasma to investigate the anti-interference ability of MOF 808-PBTCA. The specific operation was as follows: Transition metal ion salts (Co(NO 3 )) 2 , Ni(NO 3 )) 2 , Mn(NO 3 )) 2 , Zn(NO 3 )) 2 , Mg(NO 3 )) 2 , Na 2 MoO 4 , Cu(NO 3 )) 2 , Ca(NO 3 )) 2 , Hg(NO 3 )) 2 ) and rare earth ion salts (CeCl 3 , Eu(NO 3 )) 3 , Nd(NO 3 )) 3 , La(NO 3 )) 3 , Pr(NO 3 )) 3 , Sm(NO 3 )) 3 , Gd(NO 3 )) 3 , Tb(NO 3 )) 3 , Dy(NO 3 )) 3 , Ho(NO 3 )) 3 , Er(NO 3 )) 3) 2 mg each, dissolved in 20 mL of ultrapure water, to obtain a mixed solution with a concentration of 0.1 mg / mL for each transition metal salt and rare earth metal salt; 20 mg of MOF808-PBTCA prepared in Example 1 was weighed and dispersed into the above mixed solution, stirred at room temperature for 20 min, and centrifuged and filtered to obtain the supernatant and the residue. The contents of various transition metal ions and rare earth metal ions in the supernatant were detected by inductively coupled plasma. The adsorption efficiency of MOF 808-PBTCA for different metal ions in the mixed solution was calculated according to the contents of various transition metal ions and rare earth metal ions in the supernatant after adsorption and the contents of various transition metal ions and rare earth metal ions in the mixed solution before adsorption. The results are as Figure 12 shown. The adsorption efficiency of MOF 808-PBTCA for rare earth ions far exceeds that for transition metal ions, and the adsorption efficiency for rare earth ions remains above 98%, indicating that MOF 808-PBTCA has a very strong anti-interference ability.

[0100] The embodiments described above are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A porous metal organic framework derivative material for adsorbing lanthanide rare earth metal ions, characterized in that: It comprises a porous metal organic framework and small organic molecules grafted onto the porous metal organic framework; The porous metal organic framework is MOF 808; The organic small molecule is 2-phosphonobutane-1,2,4-tricarboxylic acid; The method for preparing the porous metal organic framework derivative material for adsorbing lanthanide rare earth metal ions comprises the following steps: Adding the organic small molecule dropwise into the dispersion of the porous metal organic framework, stirring continuously for 20 hours at room temperature, to obtain the porous metal organic framework derivative material for adsorbing lanthanide rare earth metal ions; The mass ratio of the organic small molecule to the porous metal organic framework is 3:

100.

2. Use of the porous metal organic framework derivative material for adsorbing lanthanide rare earth metal ions as claimed in claim 1 in the adsorption of lanthanide rare earth metal ions.

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