A metal organic framework material with detection function and its preparation method and application

Abstract

The present invention belongs to the field of electrochemical detection technology, and relates to a metal organic framework material with detection function and its preparation method and application. The technical key points are as follows: The structural formula of the metal organic framework material is [Cu 3 L 2 (DMF) 2 ]·2H 2 O; among them, C 12 N 3 S 3 O 6 H 15 (H 3 L) as an organic ligand, coordinated with transition metal copper ions, synthesized by a solvothermal method, presenting a three-dimensional structure, in which Cu1 and Cu2 are respectively 12 N 3 S 3 O 6 H 15 The five oxygen atoms in Cu3 are coordinated with the organic ligand C 12 N 3 S 3 O 6 H 15 The present invention selects an organic ligand C rich in heteroatom S. 12 N 3 S 3 O 6 H 15 With metal salt CuSO 4 •5H 2 After the coordination reaction of O, the complex material is obtained and modified on the electrode surface. By taking advantage of the fact that N and S are easy to combine with heavy metals, the electrochemical properties are improved while the sensitivity of electrochemical detection is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical detection, and relates to a metal organic framework material with detection function, a preparation method and application thereof. Background Art

[0002] With the continuous development of modern industry, the content of heavy metal ions in aqueous solution has gradually increased, causing serious harm to human health and the ecological environment. Common heavy metal ions in aqueous solution include Cd 2+ , Cu 2+ , Pb 2+ , Hg 2+ Etc. These heavy metal ions can cause certain damage to human skin, lung function, kidney function and respiratory tract, so it is very necessary to detect heavy metal ions in the environment.

[0003] At present, there are many methods for detecting and removing metal ions in aqueous solutions, such as chemical precipitation, solvent extraction, ion exchange, spectroscopy, and mass spectrometry. Compared with other heavy metal ion analysis methods, electrochemical analysis methods have the following advantages: high sensitivity, low detection limit, fast analysis speed, wide measurement range, simultaneous determination of multiple metals, simple equipment, low price, easy miniaturization and integration, easy to carry, and can realize on-site detection and online real-time monitoring. In the prior art, electrochemical detection mostly uses graphene, precious metal materials, and nano transition metal oxides, etc. However, the above materials are not only expensive, but also have disadvantages such as poor conductivity and poor activity. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art, provide a metal organic framework material with detection function and its preparation method and application, select organic ligand C rich in heteroatom S 12 N3S3O6H 15 After coordination reaction with the metal salt CuSO4•5H2O, the complex material is obtained and modified on the electrode surface. By utilizing the characteristics of easy combination of N and S with heavy metals, the electrochemical properties are enhanced while the sensitivity of electrochemical detection is improved.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] The present invention provides a metal organic framework material with detection function, which is also named Cu-MOF, and its molecular formula is [Cu3L2(DMF)2]·2H2O; wherein, the organic ligand C 12 N3S3O6H 15 .

[0007] Furthermore, Cu-MOF is a three-dimensional structure, wherein Cu1 and Cu2 are respectively 12 N3S3O6H 15 Cu3 is coordinated with 5 oxygen atoms in the ligand and 1 oxygen atom in DMF. In the above coordination mode, after Cu3 is coordinated with the organic ligand, the vacant position is coordinated with DMF, which improves the electrochemical performance and structural stability of Cu-MOF to a certain extent.

[0008] The present invention also provides a method for preparing a metal organic framework material with a detection function, comprising: 12 N3S3O6H 15 The product was uniformly dispersed in a solvent system of N,N'-dimethylformamide (DMF)-water (H2O) for hydrothermal synthesis.

[0009] Furthermore, the inorganic salt of Cu is any one of Cu sulfate, Cu halide or Cu nitrate, preferably CuSO4.

[0010] Furthermore, inorganic salts of Cu and organic ligands C 12 N3S3O6H 15 The molar ratio is 3:1.

[0011] Furthermore, in the DMF-H2O solvent system, the volume ratio of N,N'-dimethylformamide and water was 1:1, with a total of 8 mL.

[0012] Furthermore, the temperature of the hydrothermal synthesis is 80~100°C and the time is 12~48h.

[0013] The present invention also provides an application of a metal organic framework material with a detection function, including using the Cu-MOF in an electrochemical analysis method to detect heavy metal ions.

[0014] Furthermore, the heavy metal ion is Cd 2+ , Cu 2+ , Pb 2+ or Hg 2+ Any one of, and / or a mixture thereof; preferably a heavy metal ion Cd 2+ and Pb 2+ .

[0015] Furthermore, the electrochemical analysis method is any one of square wave voltammetry, cyclic voltammetry, differential pulse voltammetry or chronoamperometry, preferably square wave voltammetry.

[0016] Furthermore, Cu-MOF is used for electrochemical detection of heavy metal ions, including: using Cu-MOF to modify a bare glassy carbon electrode, and using an electrochemical three-electrode system to realize detection by an electrochemical analysis method.

[0017] Furthermore, the application of a metal organic framework material with a detection function provided by the present invention specifically includes the following steps:

[0018] A1. Prepare buffer solution;

[0019] A2, using [Cu3L2(DMF)2]·2H2O to modify the glassy carbon electrode;

[0020] A3, using a glassy carbon electrode modified with [Cu3L2(DMF)2]·2H2O as a working electrode, a reference electrode and a counter electrode to form a three-electrode system, and performing CV scanning in the buffer solution prepared in step A1 to activate the electrode and scan the background with SWV until the baseline is stable;

[0021] A4. Continuously add the metal ion solution to be tested to the buffer solution, record the peak coordinates each time, and establish a relationship diagram between current and concentration curve;

[0022] A5. Complete the linear fitting curve of the detection current and obtain the corresponding linear regression equation.

[0023] Furthermore, the conditions of the CV scan and SWV scan in step A3 are: the enrichment voltage is -1 V, the pH is 5, and the enrichment time is 300 s.

[0024] Furthermore, the number of CV scans is 10 to 18 times, preferably 12 times.

[0025] Furthermore, the reference electrode is an Ag / AgCl electrode.

[0026] Furthermore, the counter electrode is a platinum electrode.

[0027] Furthermore, the pH value of the buffer solution in step A1 is 3.0-6.5.

[0028] Furthermore, in step A2, the bare glassy carbon electrode is modified with Cu-MOF, including grinding the Cu-MOF and dispersing it in a Nafion aqueous solution, and then drop-coating it on the glassy carbon electrode.

[0029] Furthermore, the mass fraction of the Nafion aqueous solution is 0.05 wt %.

[0030] Furthermore, the buffer solution is an acetic acid-sodium hydroxide system, and its preparation method is as follows: add an appropriate amount of water and solid sodium hydroxide to glacial acetic acid, use a pH meter to measure the pH value of the solution after the temperature stabilizes, intermittently add glacial acetic acid or sodium hydroxide to adjust the pH, and finally prepare buffer solutions with different pH values, and store the prepared buffer solutions in reagent bottles for future use, check the pH value of the buffer solution regularly, and re-prepare if there is any change.

[0031] Furthermore, the present invention also provides a solution for detecting an electrode, which is used to detect the glassy carbon electrode modified with [Cu3L2(DMF)2]·2H2O provided by the present invention.

[0032] Furthermore, the detection electrode solution includes a mixed solution of K3[Fe(CN)6] and KCl, and / or a mixed solution of K3[Fe(CN)6], KCl and K4[Fe(CN)6].

[0033] Furthermore, the mixed solution of K3[Fe(CN)6] and KCl contains 5.0 mM K3[Fe(CN)6] and 1.0 M KCl; the mixed solution of K3[Fe(CN)6], KCl and K4[Fe(CN)6] contains 5.0 mM K4[Fe(CN)6], 5.0 mM K3[Fe(CN)6] and 0.1 M KCl.

[0034] Furthermore, the detection of the [Cu3L2(DMF)2]·2H2O modified glassy carbon electrode was achieved using an electrochemical three-electrode system and cyclic voltammetry.

[0035] In summary, the present invention has the following beneficial effects:

[0036] The present invention provides a metal organic framework material with detection function and a preparation method and application thereof, wherein an organic ligand C having a high content of heteroatom S is selected. 12 N3S3O6H 15 After coordination reaction with the metal salt CuSO4•5H2O, the complex material is obtained and modified on the electrode surface. By utilizing the characteristics of easy combination of N and S with heavy metals, the electrochemical properties are enhanced while the sensitivity of electrochemical detection is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the structure of Cu-MOF;

[0038] Figure 2 Schematic diagram of metal coordination in the Cu-MOF crystal structure;

[0039] Figure 3 Schematic diagram of the three-dimensional structure of Cu-MOF;

[0040] Figure 4 is the XRD pattern of Cu-MOF;

[0041] Figure 5 is the infrared spectrum of Cu-MOF;

[0042] Figure 6 This is the thermogravimetric analysis diagram of Cu-MOF;

[0043] Figure 7 The synthetic route of Cu-MOF is shown in Figure 2.

[0044] Figure 8 is the voltammetric curve of Cu-MOF;

[0045] Fig. 9 The electrochemical impedance spectroscopy diagram of Cu-MOF modified glassy carbon electrode;

[0046] Fig.10 Cd 2+ Square wave voltammogram;

[0047] Fig.11 for Fig.10 The corresponding detection current linear fitting curve diagram,

[0048] Fig.12 Pb 2+ The square wave voltammogram,

[0049] Fig.13 for Fig.12 The corresponding detection current linear fitting curve diagram,

[0050] Fig.14 For different concentrations of Cd 2+ and Pb 2+ Square wave voltammetry curve of bimetallic liquid mixture.

[0051] Fig.15 for Fig.14 The corresponding detection current linear fitting curve diagram, DETAILED DESCRIPTION

[0052] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a metal organic framework material with detection function and its preparation method and application proposed by the present invention, its specific implementation method, characteristics and effects are described in detail as follows.

[0053] The sources of raw materials used in this specific implementation are as follows:

[0054] C 12 N3S3O6H 15 : Analytical pure, Jinan Henghua Technology Co., Ltd.;

[0055] CuSO4: analytical grade, CAS No.: 7758-98-7, Anaiji Chemical;

[0056] DMF: analytical grade, CAS No.: 68-12-2, Anaiji Chemical.

[0057] This specific embodiment first provides a metal organic framework material with detection function, and its structure is as follows Figure 1 As shown, the molecular formula is [Cu3L2(DMF)2]·2H2O; where H3L is the organic ligand C 12 N3S3O6H 15 .

[0058] Figure 2 The metal coordination mode of the metal organic framework material provided in this embodiment is shown. The metal organic framework material Cu-MOF provided in this embodiment is a three-dimensional structure; wherein Cu1 and Cu2 are respectively connected with the organic ligand C 12 N3S3O6H 15 The five oxygen atoms in Cu3 are coordinated with the organic ligand C 12 N3S3O6H 15 The four oxygen atoms in are coordinated with one oxygen atom in DMF.

[0059] Among them, the organic ligand C 12 N3S3O6H 15 The structural formula is: .

[0060] This specific embodiment also provides a method for preparing a metal organic framework material, wherein an inorganic salt of Cu and an organic ligand C 12 N3S3O6H 15 Evenly dispersed in a DMF-water solvent system, hydrothermal synthesis was performed, specifically:

[0061] S1. Inorganic salt of Cu and organic ligand C 12 N3S3O6H 15 Mix, evenly disperse in a DMF-water solvent system, and stir to obtain solution A;

[0062] S2. Transfer solution A to a reactor, heat for reaction, and after cooling to room temperature, obtain the product metal organic framework material Cu-MOF.

[0063] As a preference of the above embodiment, the inorganic salt of Cu is any one of Cu sulfate, Cu halide or Cu nitrate, more preferably CuSO4.

[0064] As a preferred embodiment of the above, the inorganic salt of Cu and the organic ligand C 12 N3S3O6H15 The molar ratio is (3~4):1.

[0065] As a preference in the above embodiment, the stirring time in step S1 is 10 to 30 minutes.

[0066] As a preference of the above embodiment, the heating temperature in step S2 is 80-100° C., and the reaction time is 12-24 hours.

[0067] The metal organic framework material Cu-MOF prepared by this specific embodiment is a blue crystal, which can be used to detect heavy metal ions in aqueous solution and has the advantages of high detection sensitivity and low detection limit.

[0068] This specific embodiment also provides an application of a metal organic framework material with detection function, including using the Cu-MOF in an electrochemical analysis method to detect heavy metal ions.

[0069] In some preferred embodiments, the heavy metal ion detected is Cd 2+ , Cu 2+ , Pb 2+ or Hg 2+ Any one of, and / or a mixture thereof, in a more preferred embodiment, detecting Cd 2+ and Pb 2+ .

[0070] In some preferred embodiments, the electrochemical analysis method is any one of square wave voltammetry, cyclic voltammetry, differential pulse voltammetry or chronoamperometry, more preferably square wave voltammetry.

[0071] In some preferred embodiments, Cu-MOF is used for electrochemical detection of heavy metal ions, specifically including: using Cu-MOF to modify a bare glassy carbon electrode, using the electrode modification to construct a sensitive interface, and using an electrochemical three-electrode system to realize detection by an electrochemical analysis method.

[0072] More specifically, the steps include:

[0073] A1. Prepare buffer solution;

[0074] A2, using [Cu3L2(DMF)2]·2H2O to modify the glassy carbon electrode;

[0075] A3, using a glassy carbon electrode modified with [Cu3L2(DMF)2]·2H2O as a working electrode, a reference electrode and a counter electrode to form a three-electrode system, and performing CV scanning in the buffer solution prepared in step A1 to activate the electrode and scan the background with SWV until the baseline is stable;

[0076] A4. Continuously add the metal ion solution to be tested to the buffer solution, record the peak coordinates each time, and establish a relationship diagram between current and concentration curve;

[0077] A5. Complete the linear fitting curve of the detection current and obtain the corresponding linear regression equation.

[0078] Furthermore, the conditions of the CV scan and SWV scan in step A3 are: the enrichment voltage is -1 V, the pH is 5, and the enrichment time is 300 s.

[0079] The number of CV scans is preferably 10 to 18 times, more preferably 12 times; the reference electrode and the counter electrode are electrodes commonly used in the field of electrochemistry, the reference electrode is an Ag / AgCl electrode, and the counter electrode is preferably a platinum electrode.

[0080] In some preferred embodiments, the pH value of the buffer solution in step A1 is 3.0-6.5, and the more preferred pH value is 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0 and / or 6.5; the buffer solution is an acetic acid-sodium hydroxide system, and its preparation method is as follows: add an appropriate amount of water and solid sodium hydroxide to glacial acetic acid, measure the pH value of the solution with a pH meter after the temperature of the solution stabilizes, intermittently add glacial acetic acid or sodium hydroxide to adjust the pH, and finally prepare buffer solutions with different pH values, and store the prepared buffer solutions in reagent bottles for standby use, regularly check the pH value of the buffer solution, and re-prepare if there is any change.

[0081] In some preferred embodiments, in step A2, the bare glassy carbon electrode is modified with Cu-MOF, including grinding the Cu-MOF and dispersing it in a Nafion aqueous solution, and then drop-coating it on the glassy carbon electrode. The mass fraction of the Nafion aqueous solution is preferably 0.05 wt%.

[0082] In some preferred embodiments, the bare glassy carbon electrode is modified with Cu-MOF, comprising: grinding the Cu-MOF and dispersing it in a Nafion aqueous solution, and drop-coating it on the glassy carbon electrode; specifically, grinding the Cu-MOF crystals into powder in an agate mortar, placing it in a Nafion aqueous solution, and ultrasonically dispersing it for 20 to 30 minutes to obtain a Cu-MOF dispersion; polishing the surface of the bare electrode with 0.3 μm and 0.05 μm Al2O3 powders, respectively, and then ultrasonically washing the glassy carbon electrode with distilled water to obtain a bright surface; and applying the Cu-MOF dispersion on the glassy carbon electrode by drop-coating to obtain a Cu-MOF modified glassy carbon electrode.

[0083] This specific embodiment also provides a detection electrode solution for detecting the [Cu3L2(DMF)2]·2H2O modified glassy carbon electrode provided by the present invention, and the detection electrode solution includes a mixed solution of K3[Fe(CN)6] and KCl, and / or a mixed solution of K3[Fe(CN)6], KCl and K4[Fe(CN)6].

[0084] In some preferred embodiments, the mixed solution of K3[Fe(CN)6] and KCl contains 5.0 mM K3[Fe(CN)6] and 1.0 M KCl; the mixed solution of K3[Fe(CN)6], KCl and K4[Fe(CN)6] contains 5.0 mM K4[Fe(CN)6], 5.0 mM K3[Fe(CN)6] and 0.1 M KCl.

[0085] In some preferred embodiments, the detection of the glassy carbon electrode modified with [Cu3L2(DMF)2]·2H2O is achieved by using an electrochemical three-electrode system and cyclic voltammetry.

[0086] Example 1: A metal organic framework material with detection function and preparation method thereof

[0087] The metal organic framework material with detection function provided in this embodiment is denoted as Cu-MOF, and its molecular formula is [Cu3L2(DMF)2]·2H2O. Figure 1 and 2 As shown in the figure, it is a three-dimensional structure. In its molecular unit, Cu1 and Cu2 are respectively connected with the organic ligand C 12 N3S3O6H 15 The five oxygen atoms in Cu3 are coordinated with the organic ligand C 12 N3S3O6H 15 The four oxygen atoms in are coordinated with one oxygen atom in DMF.

[0088] This embodiment also provides a method for preparing the metal organic framework material with detection function. The reaction equation is as follows: Figure 6 The following steps are included:

[0089] S1, CuSO4 and organic ligand C 12 N3S3O6H 15 Mix in a molar ratio of 3:1, uniformly disperse in a DMF-water solvent system, and stir to obtain solution A;

[0090] S2. Transfer solution A to a reactor and heat it to 80°C. After the reaction is completed, cool it to room temperature to obtain blue crystals, which are the product, the metal organic framework material Cu-MOF.

[0091] The crystal structure of the metal organic framework material with inspection function provided in this embodiment is determined as follows:

[0092] The diffraction data of Cu-MOF were collected on an Oxford Diffraction Gemini R Ultra diffractometer, MoKα radiation (λ = 0.71073Å), 293 K. The crystal structure was solved by the direct method and refined by SHELXL-2018 in Wingx. All non-hydrogen atoms were corrected by anisotropic temperature factors, and hydrogen on carbon atoms was obtained by theoretical hydrogenation. The refinement parameters are shown in Table 1, and some bond lengths and angles are shown in Table 2.

[0093] Table 1 shows the main crystallographic data of Cu-MOF in Example 1

[0094] Compound Cu-MOF Formula <![CDATA[Cu3C 30 H 40 N8O 15 S6]]> 1118.67 Temperature (K) 293(2) Crystal system Triclinic Space group 1 (Å) 11.4638(10) (Å) 12.5600(11) (Å) 16.3969(14) (°) 77.050(3) (°) 78.707(3) (°) 78.617(3) <![CDATA[ V (Oh 3 )]]> 2227.0(3) 2 <![CDATA[ D calc (g . cm -3 )]]> 1.668 (000) 1140 int 0.0855 <![CDATA[GOF on F 2 ]]> 1.024 <![CDATA[ R 1, wxya 2[I>2σ(I)]]]> 0.0713, 0.1812 <![CDATA[ R 1, wxya 2 (all data)]]> 0.1385, 0.2191

[0095] Table 2 shows the bond lengths (Å) and bond angles (°) of some Cu-MOFs in Example 1

[0096] O(1)-Cu(2) 1.934(5) <![CDATA[O(4) #2 -Cu(1)-Cu(2)]]> 168.40(12) O(2)-Cu(1) 1.958(5) <![CDATA[O(1)-Cu(2)-O(11) #3 ]]> 171.7(2) <![CDATA[O(3)-Cu(2) #1 ]]> 2.024(4) O(1)-Cu(2)-O(7) 88.2(2) <![CDATA[O(4)-Cu(1) #1 ]]> 1.978(4) <![CDATA[O(11) #3 -Cu(2)-O(7)]]> 91.7(2) <![CDATA[O(4)-Cu(1) #2 ]]> 2.214(4) <![CDATA[O(1)-Cu(2)-O(3) #3 ]]> 90.7(2) O(7)-Cu(2) 2.005(4) <![CDATA[O(11) #3 -Cu(2)-O(3) #3 ]]> 87.0(2) O(8)-Cu(1) 1.920(4) <![CDATA[O(7)-Cu(2)-O(3) #3 ]]> 162.74(19) <![CDATA[Cu(1)-O(12) #3 ]]> 1.966(5) O(1)-Cu(2)-O(13) 94.1(2) Cu(1)-Cu(2) 2.6173(11) <![CDATA[O(11) #3 -Cu(2)-O(13)]]> 94.2(2) <![CDATA[Cu(2)-O(11) #3 ]]> 1.954(5) O(7)-Cu(2)-O(13) 98.6(2) Cu(2)-O(13) 2.149(5) <![CDATA[O(3) #3 -Cu(2)-O(13)]]> 98.7(2) <![CDATA[Cu(3)-O(6) #4 ]]> 1.955(5) O(1)-Cu(2)-Cu(1) 86.74(16) Cu(3)-O(5) 1.956(5) <![CDATA[O(11) #3 -Cu(2)-Cu(1)]]> 85.01(15) <![CDATA[Cu(3)-O(9) #2 ]]> 1.956(5) O(7)-Cu(2)-Cu(1) 80.88(14) <![CDATA[Cu(3)-O(10) #5 ]]> 1.970(5) <![CDATA[O(3) #3 -Cu(2)-Cu(1)]]> 81.86(13) Cu(3)-O(14) 2.152(5) O(13)-Cu(2)-Cu(1) 179.05(19) <![CDATA[Cu(3)-Cu(3) #4 ]]> 2.6198(16) <![CDATA[O(6) #4 -Cu(3)-O(5)]]> 168.5(2) C(6)-O(1)-Cu(2) 120.8(5) <![CDATA[O(6) #4 -Cu(3)-O(9) #2 ]]> 89.8(2) C(6)-O(2)-Cu(1) 124.5(5) <![CDATA[O(5)-Cu(3)-O(9) #2 ]]> 89.5(2) <![CDATA[C(9)-O(3)-Cu(2) #1 ]]> 125.5(4) <![CDATA[O(6) #4 -Cu(3)-O(10) #5 ]]> 88.7(3) <![CDATA[C(9)-O(4)-Cu(1) #1 ]]> 121.1(4) <![CDATA[O(5)-Cu(3)-O(10) #5 ]]> 89.7(3) <![CDATA[C(9)-O(4)-Cu(1) #2 ]]> 140.2(4) <![CDATA[O(9) #2 -Cu(3)-O(10) #5 ]]> 168.2(2) <![CDATA[Cu(1) #1 -O(4)-Cu(1) #2 ]]> 98.49(18) <![CDATA[O(6) #4 -Cu(3)-O(14)]]> 97.1(2) C(13)-O(7)-Cu(2) 124.5(4) O(5)-Cu(3)-O(14) 94.4(2) C(13)-O(8)-Cu(1) 120.4(4) <![CDATA[O(9) #2 -Cu(3)-O(14)]]> 98.7(2) O(8)-Cu(1)-O(2) 89.5(2) <![CDATA[O(10) #5 -Cu(3)-O(14)]]> 93.1(2) <![CDATA[O(8)-Cu(1)-O(12) #3 ]]> 91.3(2) <![CDATA[O(6) #4 -Cu(3)-Cu(3) #4 ]]> 83.80(16) <![CDATA[O(2)-Cu(1)-O(12) #3 ]]> 166.1(2) <![CDATA[O(5)-Cu(3)-Cu(3) #4 ]]> 84.66(16) <![CDATA[O(8)-Cu(1)-O(4) #3 ]]> 174.9(2) <![CDATA[O(9) #2 -Cu(3)-Cu(3) #4 ]]> 84.95(16) <![CDATA[O(2)-Cu(1)-O(4) #3 ]]> 90.4(2) <![CDATA[O(10) #5 -Cu(3)-Cu(3) #4 ]]> 83.28(16) <![CDATA[O(12) #3 -Cu(1)-O(4) #3 ]]> 87.6(2) <![CDATA[O(14)-Cu(3)-Cu(3) #4 ]]> 176.26(16) <![CDATA[O(8)-Cu(1)-O(4) #2 ]]> 103.53(18) C(12)-O(5)-Cu(3) 122.2(5) <![CDATA[O(2)-Cu(1)-O(4) #2 ]]> 97.96(19) <![CDATA[C(12)-O(6)-Cu(3) #4 ]]> 123.3(5) <![CDATA[O(12) #3 -Cu(1)-O(4) #2 ]]> 95.32(19) <![CDATA[C(21)-O(11)-Cu(2) #1 ]]> 121.9(5) <![CDATA[O(4) #3 -Cu(1)-O(4) #2 ]]> 81.51(18) <![CDATA[C(21)-O(12)-Cu(1) #1 ]]> 122.5(5) O(8)-Cu(1)-Cu(2) 88.07(15) <![CDATA[C(24)-O(9)-Cu(3) #2 ]]> 122.7(5) O(2)-Cu(1)-Cu(2) 82.22(15) <![CDATA[C(24)-O(10)-Cu(3) #6 ]]> 123.8(5) <![CDATA[O(12) #3 -Cu(1)-Cu(2)]]> 83.97(15) C(28)-O(14)-Cu(3) 115.5(5) <![CDATA[O(4) #3 -Cu(1)-Cu(2)]]> 86.88(13)

[0097] Note: Symmetric code: #1 x, y+1, z; #2 -x, -y+1, -z; #3 x, y-1, z; #4 -x-1, -y, -z+1; #5 x-1, y-1, z+1; #6 x+1, y+1, z-1.

[0098] According to Table 1 and Table 2, the Cu-MOF crystal provided in this embodiment belongs to the triclinic system, and the space group is P- 1, the unit cell parameters are a = 11.4638(10) Å, b = 12.5600(11) Å, c = 16.3969(14) Å, α = 77.050(3)°, β = 78.707(3)°, γ = 78.617(3)°, V = 2227.0(3) Å 3 , is a three-dimensional frame structure.

[0099] The characterization of the metal organic framework material with inspection function provided in this embodiment is as follows Figures 4 to 6 .

[0100] Figure 4This is the PXRD diagram of the metal organic framework material Cu-MOF provided in this specific embodiment. As can be seen from the figure, the PXRD diffraction peaks of Cu-MOF are consistent with the diffraction peaks obtained by simulation. Powder X-ray diffraction detection shows that the phase purity of the Cu-MOF crystals provided in this embodiment is high.

[0101] Figure 5 This is the infrared spectrum. The main infrared absorption peaks are: 3572.35 (s), 3485.39 (m), 2942.98(s), 1737.43 (s), 1656.49 (m), 1612.47 (w), 1480.24 (w), 1433.18 (w), 1312.47(m), 1243.35 (w), 1217.83 (w), 1154.00 (m), 1107.27 (w), 985.66 (s), 927.39(s), 837.38 (m), 787.22 (m), 696.32 (m), 665.40 (m), 639.46 (s), 613.23 (m), 517.51 ​​(s), 491.51 (s), 447.74 (s), 413.89 (m).

[0102] Figure 6 This is a thermogravimetric analysis diagram; the thermogravimetric analysis of the compound was carried out in a nitrogen atmosphere at a temperature range of 30°C to 800°C. It can be seen from the figure that before 210.3°C, the compound lost 1.88% of its weight, corresponding to a free water molecule.

[0103] Example 2: Application of a metal organic framework material with detection function

[0104] This embodiment provides a method for using the Cu-MOF prepared in Example 1 to detect heavy metal ions in an aqueous solution, which specifically includes the following steps:

[0105] A1. Prepare buffer solution. Add appropriate amount of water and solid sodium hydroxide to glacial acetic acid. After the solution temperature stabilizes, use a pH meter to measure its pH value. Add glacial acetic acid or sodium hydroxide intermittently to adjust the pH. Finally, prepare 250 ml of buffer solutions with pH values ​​of 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0 and 6.5, respectively. Store the prepared buffer solutions in reagent bottles for future use. Check the pH value of the buffer solution regularly. If there is any change, re-prepare.

[0106] A2, using [Cu3L2(DMF)2]·2H2O to modify the glassy carbon electrode, 3 mg of Cu-MOF was ground into powder in an agate mortar, dispersed in 1 mL of 0.05% Nafion solution, and ultrasonically dispersed to obtain a Cu-MOF dispersion; the surface of the bare glassy carbon electrode was polished with 0.3μm and 0.05μm Al2O3 powders, respectively, and the glassy carbon electrode was cleaned with distilled water after ultrasonication to obtain a bright surface, and the above dispersion was modified on the glassy carbon electrode by drop coating to obtain a [Cu3L2(DMF)2]·2H2O modified glassy carbon electrode;

[0107] A5, respectively configure 0.001M Cd 2+ , Pb 2+ Metal ion solution: add 1.8332 g of cadmium chloride and 3.2529 g of lead acetate to 100 mL of water to prepare 100 mL of 0.1 M Cd(II) metal ion solution and 100 mL of 0.1 M Pb(II) metal ion solution. Accurately pipette 1 mL of each and dilute to 100 mL to prepare 100 mL of 0.001 M Cd(II) and Pb(II) metal ion solutions respectively.

[0108] A2, take 10mL of buffer solution, mix different concentrations of Cd 2+ , Pb 2+ , Hg 2+ The ions were added to the buffer solution, mixed and stirred thoroughly, and a three-electrode system was formed with a glassy carbon electrode modified with [Cu3L2(DMF)2]·2H2O as the working electrode, Ag / AgCl as the reference electrode, and a platinum electrode as the counter electrode;

[0109] A3, under the conditions of 300s of collection time, -1V of collection voltage and pH 5, 12 CV scans were performed in a blank buffer solution to activate the electrode, and then the background was scanned by SWV until the baseline was stable;

[0110] A8, continue to add standard 0.001 M Cd 2+ solution, with the increase of metal ion concentration, Cd 2+ The peak current also increases accordingly. Record the peak coordinates each time and repeat the above operation to complete the Pb 2+ The detection of Cd 2+ and Pb 2+ The relationship diagram between the detection current and the concentration curve when detecting alone, complete the detection current linear fitting curve, and obtain the corresponding linear regression equation;

[0111] A9. Re-adjust the experimental equipment and add Cd to the blank buffer solution in a gradient manner. 2+ , Pb 2+solution and record its image peak coordinates to establish Cd 2+ and Pb 2+ The relationship diagram of the detection current and concentration curve during joint detection is completed, and the detection current linear fitting curve is completed to obtain the corresponding linear regression equation.

[0112] Before conducting the test of this example, a mixed solution of 5.0 mM K4[Fe(CN)6], 5.0 mM K3[Fe(CN)6] and 0.1 M KCl was used as the electrode detection solution. Under the conditions of an enrichment time of 300 s, an enrichment voltage of -1 V and a pH value of 5, a cyclic voltammetric scan was performed using the three-electrode system provided in this example to detect the [Cu3L2(DMF)2]·2H2O-modified glassy carbon electrode provided in this example.

[0113] Test results are shown in Figures 8 to 15 ;in, Figure 8 is the voltammetric curve, Fig. 9 is the electrochemical impedance spectroscopy, Figure 8 and Fig. 9 It can be seen that after modification with [Cu3L2(DMF)2]·2H2O, the conductivity of the glassy carbon electrode is greatly improved, which shows that the [Cu3L2(DMF)2]·2H2O material provided by the present invention has a high conductivity.

[0114] Fig.10 Cd 2+ The square wave voltammogram shows that the addition of Cd 2+ Afterwards, the oxidation current increased significantly at -0.788 V, and the detection limit could be as low as 3 μM, with a linear range of 3~22 μM. Fig.11 The corresponding detection current linear fitting curve is in line with I (μA) = 0.0503 C (μM) - 1.4118 in the low concentration range of 0~10μM, R 2 = 0.9794; at 10~25μM, it complies with I (μA) = 0.1055 C (μM) - 6.9500, R 2 = 0.9900.

[0115] Fig.12 Pb 2+ Square wave voltammogram, as shown in the figure, adding Pb 2+ Afterwards, the oxidation current increased significantly at -0.54 V, and the detection limit could be as low as 2 μM, with a linear range of 2 to 14 μM; Fig.13 The corresponding detection current linear fitting curve is in accordance with I (μA) = 0.3893 C (μM) – 6.0132, R 2 = 0.9899.

[0116] Fig.14 For different concentrations of Cd 2+ and Pb 2+ The square wave voltammetric curve of the bimetallic mixture has a linear range of 2~22μM and does not interfere with each other. Fig.15 is the corresponding detection current linear fitting curve, for Cd 2+ , in the low concentration range, it complies with I(μA) = 0.1995 C (μM) - 3.2231, R 2 = 0.9825; in the higher concentration range, it is consistent with I (μA) = 0.01577C (μM) - 0.2878, R 2 = 0.9897. For Pb 2+ , in accordance with I (μA) = 0.03732 C (μM) - 1.8131, R 2 =0.9909. This shows that the metal skeleton material provided in this embodiment can achieve the heavy metal ion Cd 2+ , Pb 2+ The detection is of high sensitivity and low detection limit.

[0117] In addition, Cu-MOF materials have high electrical conductivity and can realize the 2+ , Pb 2+ The purpose of the test. 2+ or Pb 2+ When Cu-MOF and Cd 2+ , Pb 2+ The interaction between the two improves the detection current intensity value and realizes the detection of Cd 2+ , Pb 2+ The sensor has good conductivity, stability and selectivity. Compared with other detection methods, this method has a wider detection range and lower detection limit, which can achieve Cd 2+ , Pb 2+ Trace detection.

[0118] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been presented as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A metal organic framework material with detection function, characterized in that: The metal organic framework material is Cu-MOF, and the molecular formula is [Cu3L2(DMF)2]·2H2O; wherein L is a ligand L with three protons removed. 3- ; The L 3- The structural formula is: ； The Cu-MOF crystal belongs to the triclinic system, and the space group is P- 1, the unit cell parameters are a = 11.4638(10) Å, b = 12.5600(11) Å, c = 16.3969(14) Å, α = 77.050(3)°, β = 78.707(3)°, γ = 78.617(3)°, V = 2227.0(3) Å 3 , is a three-dimensional frame structure.

2. The metal organic framework material with detection function according to claim 1, characterized in that: In the structural unit of the Cu-MOF, Cu1 and Cu2 are respectively bonded to the organic ligand C 12 N3S3O6H 15 The five oxygen atoms in Cu3 are coordinated with the organic ligand C 12 N3S3O6H 15 The four oxygen atoms in are coordinated with one oxygen atom in DMF.

3. The method for preparing a metal organic framework material with detection function according to any one of claims 1 to 2, characterized in that: include: The inorganic salt of Cu and the organic ligand C 12 N3S3O6H 15 It is uniformly dispersed in a DMF-water solvent system and subjected to hydrothermal synthesis at a temperature of 80-100°C for 12-48 hours.

4. The method for preparing a metal organic framework material with detection function according to claim 3, characterized in that: The inorganic salt of Cu is any one of Cu sulfate, Cu halide or Cu nitrate.

5. The method for preparing a metal organic framework material with detection function according to claim 4, characterized in that: The Cu inorganic salt and the organic ligand C 12 N3S3O6H 15 The molar ratio is (3~4):

1.

6. The use of a metal organic framework material with detection function as claimed in any one of claims 1 to 2, characterized in that: The invention comprises using the Cu-MOF in an electrochemical analysis method to detect heavy metal ions.

7. The use of a metal organic framework material with detection function according to claim 6, characterized in that: The heavy metal ion is Cd 2+ , Cu 2+ , Pb 2+ or Hg 2+ Any one of them, or a mixture thereof.

8. The use of a metal organic framework material with detection function according to claim 6, wherein the electrochemical analysis method is any one of square wave voltammetry, cyclic voltammetry, differential pulse voltammetry or chronoamperometry.

9. The use of a metal organic framework material with detection function according to claim 6, characterized in that: The Cu-MOF is used for electrochemical detection of heavy metal ions, including: using the Cu-MOF to modify a bare glassy carbon electrode for electrode modification, constructing a sensitive interface, and using an electrochemical three-electrode system to realize detection by an electrochemical analysis method.

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