Wurster-type covalent organic framework materials, methods of preparation, and applications thereof in gold adsorption

Abstract

The application discloses a Wurster type covalent organic framework material, a preparation method and application thereof in gold adsorption, and a structural formula is as follows: any one of the obtained materials has an adsorption ratio of less than 5% for various impurity ions in acid wastewater, but has an adsorption ratio of 99.9% for gold elements, and a gold element recovery rate of 99.9% in a circuit board and CPU leaching solution, and can be used for adsorption and recovery of gold elements in various recovery materials.

Description

Technical Field

[0001] The present invention relates to the technical field of Wurster type covalent organic framework materials, in particular to a Wurster type covalent organic framework material, a preparation method and its application in gold adsorption. Background Art

[0002] With the rapid upgrading of electronic devices, discarded electronic products are gradually becoming "urban mines." Efficient and environmentally friendly recycling of gold from these resources can not only reduce dependence on natural gold mines, but also reduce the environmental pollution caused by electronic waste.

[0003] Adsorption, precipitation, solvent extraction, and ion exchange techniques have been widely used to recover gold from electronic waste leachate. Among them, adsorption based on porous adsorbents has gradually become the mainstream technology for gold recovery due to its environmental friendliness, low cost, and ease of operation.

[0004] Covalent organic frameworks (COFs) are a new class of highly crystalline, porous organic polymers. Organic building blocks connected by strong covalent bonds make COFs tunable in porosity, skeleton structure and chemical stability, and are widely used in the field of precious metal adsorption.

[0005] Although many studies have achieved certain results in improving the adsorption performance of COFs, the existing technologies face disadvantages such as expensive raw material costs, complex synthesis processes, the need for additional energy input, low recovery capacity, and lack of selectivity.

[0006] For example, CN202210907161.3 discloses a crown ether covalent organic framework material, its preparation method, and its application in the adsorption and separation of palladium. This material can specifically adsorb and separate palladium from an acidic aqueous phase containing 19 metal ions, achieving a single-stage adsorption rate of over 94% for palladium ions. This material demonstrates high selectivity, ease of operation, and high separation efficiency, making it particularly suitable for separating and recovering precious metal palladium in the nuclear industry. However, this material is unable to effectively adsorb gold.

[0007] Another example is the porous composite material, its preparation method and application disclosed in CN202211390039.X, which relates to the technical field of environmental functional materials. By forming a metal polyphenol network structure (MPN) in the pores and surface of the covalent organic framework (COFs) material, and by combining well-characterized COFs and MPN materials, a layered porous composite material COFs@MPN is synthesized. The prepared composite material has a high specific surface area and porous structure, and provides surface support for COFs, effectively improves the mechanical strength of COFs, changes the three-dimensional pore structure of COFs, and improves its adsorption performance and stability for caffeine in practical applications. This material still cannot be used for the effective adsorption of gold in an environment with a large amount of impurity ions.

[0008] Therefore, there is an urgent need to develop a cheap and efficient gold recovery agent. The information disclosed in the background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as admitting or suggesting in any form that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the Invention

[0009] The present application provides a Wurster-type covalent organic framework material, a preparation method and its application in gold adsorption, which can be used as a cheap and efficient gold (Au) recovery agent.

[0010] The present application provides a Wurster-type covalent organic framework material, the structural formula of which is any of the following:

[0011]

[0012]

[0013]

[0014] Another aspect of the present application further provides a use of the Wurster-type covalent organic framework material as described above in gold adsorption, with a gold recovery rate of >99.9%.

[0015] Another aspect of the present application provides a method for gold element adsorption recovery, comprising: adding the Wurster type covalent organic framework material as described above to an acidic solution, shaking and mixing, filtering, and adsorbing the gold element into the resulting solid;

[0016] The acidic solution is an acidic simulated solution containing gold elements or an acidic waste liquid containing gold elements.

[0017] Preferably, the acidic solution contains Pd 2+ , Pt 4+ 、Ba 2+ , K + 、Na + , Ca 2+ 、Co 2+ 、Fe 3+ Mg 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ 、Mn 2+ 、Hg 2+ , Pb 2+ 、Al 3+ and Cd 2+ The concentration of each interfering ion in the solution can be at least 50 mg / L.

[0018] Preferably, when the acidic simulated liquid containing gold elements is a NaAuCl4 solution with a pH value of 1.0 to 10.0, the amount of Wurster-type covalent organic framework material used is 2 mg; the initial concentration of gold elements in the acidic simulated solution is 50 to 500 mg / L; the shaking mixing condition is shaking at 25°C for 24 hours; and filtration is performed using a 0.22 μm filter head.

[0019] Preferably, the acidic waste liquid containing gold elements is a leaching liquid of at least one of a circuit board, a CPU, and a wafer chip.

[0020] Preferably, when the acidic solution is a leaching solution obtained by mixing a circuit board and a CPU, the gold element absorption rate is 99.9%.

[0021] Another aspect of the present application further provides a method for preparing the Wurster-type covalent organic framework material as described above, comprising the following steps:

[0022] Mixing the reaction raw materials and the reaction solvent and then sonicating to obtain a mixture;

[0023] Aqueous acetic acid solution was added to the resulting mixture, which was degassed by three freeze-pump-thaw cycles in a liquid nitrogen bath and heated at a constant temperature to obtain a solid;

[0024] The solid obtained after Soxhlet extraction and drying is a Wurster-type covalent organic framework material;

[0025] The reaction raw materials are at least two of the monomers A to C of the following structural formulas;

[0026]

[0027] From the structures of monomers A to C above, we can see that the raw material combinations for the Schiff base reaction to form COF can be: monomer A + B, monomer B + C, monomer A + B + C;

[0028] Preferably, the reaction solvent is a mixture of o-dichlorobenzene and n-butanol in a volume ratio of 1:1, or a mixture of trimethylbenzene and hexacyclopentasiloxane in a volume ratio of 1:1; the constant temperature heating is heating the reaction at 100-140° C. for 48-96 hours;

[0029] The concentration of the acetic acid aqueous solution used is 5-8 mol / L, and the amount of the acetic acid aqueous solution additive is 0.1-0.3 ml;

[0030] The washing solvents used in Soxhlet extraction were acetone, tetrahydrofuran and n-hexane, respectively;

[0031] The method further comprises: performing Soxhlet extraction on the obtained solid for 20 to 28 hours, and then vacuum drying at 60 to 80° C. to obtain the Wurster type covalent organic framework material.

[0032] Preferably, when the reaction raw materials are phthalaldehyde substances and N,N,N',N'-tetrakis(p-aminophenyl)-p-phenylenediamine, the molar ratio of phthalaldehyde substances and N,N,N',N'-tetrakis(p-aminophenyl)-p-phenylenediamine is: 1:0.5;

[0033] When the reaction raw materials are monomer B, monomer A, and monomer C, the molar ratio of monomer B:monomer A+C is 1:2.

[0034] The beneficial effects of this application include:

[0035] 1) The Wurster-type covalent organic framework materials, preparation methods, and applications in gold adsorption provided in this application adopt a three-component mixed ligand strategy, with electron-rich Wurster-type monomers as building blocks. By adjusting the ratio of linear monomers and V-shaped monomers, a series of novel three-component covalent organic frameworks with multi-level pore structures have been successfully constructed. By rationally regulating the ratio of isomers, this method achieves effective regulation of the original COF morphology and pore structure. The three-component Wurster-type covalent organic framework of the present invention exhibits excellent selectivity and high adsorption capacity in electronic waste and metallurgical wastewater, and has important practical value.

[0036] 2) The Wurster-type covalent organic framework material, preparation method, and application in gold adsorption provided in this application have an adsorption rate of less than 5% for various impurity ions in acidic wastewater, but an adsorption rate of gold as high as 99.9%. The gold recovery rate in mixed leachates of circuit boards and CPUs can reach 99.9%, and can be used for the adsorption and recovery of gold in various recycled materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The powder X-ray diffraction patterns of the covalent organic frameworks obtained in Examples 1 to 4 of the present application demonstrate the structural characteristics of the materials under different synthesis conditions. Figure 1 The black line in (a) is Tpa-2DCOF, the material obtained in Example 1; Figure 1 The blue line in (b) is the TpaIda-2DCOF obtained in Example 2; Figure 1 The red line Ida-1DCOF in (b) is the material obtained in Example 3; Figure 1 The green line in (b) is the IdaTpa-1DCOF obtained in Example 4; the two lines in the lower half of the figure are PXRD spectra simulated by the calculation software. Figure 1 (a) The experimental curve in the upper part matches well with the fitting curve of kgm-AA stacking. Figure 1(b) The experimental curve of the upper part matches the fitting curve of the interpenetrated stack better. This indicates that the incorporation of a small amount of m-xylylene glycol into p-xylylene glycol does not change the topology of the obtained covalent organic framework (i.e. the PXRD is almost identical); the incorporation of a small amount of p-xylylene glycol into m-xylylene glycol also does not change the topology of the obtained covalent organic framework (i.e. the PXRD is almost identical).

[0038] Figure 2 The scanning electron microscope morphologies of the covalent organic framework materials obtained in Examples 1-4 of the present application show the morphological differences of different covalent organic framework materials, and the different morphologies indicate the effectiveness of the mixed monomer strategy in the synthesis. Figure 2 (a) is IdaTpa-1D COF, the material obtained in Example 4; Figure 2 (b) is Ida-1D COF, the material obtained in Example 2; Figure 2 (c) is Tpa-2D COF, the material obtained in Example 1; Figure 2 (d) is TpaIda-2D COF, the material obtained in Example 3.

[0039] Figure 3 The scanning electron microscope morphologies of the material obtained in Example 3 of the present application after the material adsorbed gold elements show that the gold nanoparticles are attached to the surface of the covalent organic framework, proving that the material has excellent adsorption performance; the red Au traces and the similar shapes are all gold nanoparticles, and the yellow circular marks are TpaIda-2D COF.

[0040] Figure 4 The structure schematic diagram of the raw materials used in Examples 1-4 of the present application is shown. DETAILED DESCRIPTION

[0041] The present application will be further described in detail below in combination with the drawings and examples, but the present application is not limited in any way by the following description, and any transformation or improvement based on the teaching of the present application falls within the protection scope of the present application.

[0042] EXAMPLE

[0043] The materials and instruments used in the following examples are obtained from commercial channels unless otherwise specified; the detection methods used are all existing methods unless otherwise specified.

[0044] Example 1: Preparation of a two-dimensional covalent organic framework

[0045] In a glass tube, p-xylylene glycol (structure as Figure 4 A, 13.4 mg, 0.10 mmol), N,N,N',N'-tetra(p-aminophenyl)-p-phenylenediamine (structure as Figure 4

[00145] A mixture of 1,2-dichlorobenzene (2.0 ml) and n-butanol (2.0 ml) was added and ultrasonicated at 40 kHz for 10 minutes to obtain a mixture. An aqueous acetic acid solution (0.2 mL, 6 mol / L) was then added to the mixture. The glass tube was degassed in a liquid nitrogen bath by three freeze-pump-thaw cycles.

[0046] The freeze-pump-thaw cycle degassing process is as follows: first, place the glass tube in liquid nitrogen and freeze it for 1 minute. Then, turn on the vacuum pump to evacuate the air. After 5 minutes, turn off the vacuum and flush nitrogen into the glass tube. Then, place the glass tube in water to completely melt all the solids. After the solids have melted, repeat this process three times.

[0047] The mixture was heated in an oven at a constant temperature of 120°C for 3 days to obtain a mixture of a reddish-brown precipitate and a solvent. After cooling to room temperature, the reddish-brown solid was filtered and the resulting solid precipitate was washed with tetrahydrofuran. After washing, the solid was placed in a tea bag and placed in a Soxhlet extractor. Acetone, tetrahydrofuran and n-hexane were used as solvents to continuously wash the solid in sequence for 24 hours. The solid was placed in a vacuum drying oven and evacuated to an internal pressure of 20 mTorr, and dried at 80 degrees for 24 hours to obtain Tpa-2DCOF as a reddish-brown powder (yield 92%). According to the network chemistry theory, the two raw materials with the above symmetry were used to react, and the COF constructed was a two-dimensional network structure.

[0048] The obtained Tpa-2DCOF material structure is shown below:

[0049]

[0050] Tpa-2DCOF is a schematic diagram of the structure of the material obtained in Example 1. The structure is a kgm topological structure with a hexagonal and triangular double pore structure.

[0051] Example 2: Preparation of TpaIda-2DCOF

[0052] The difference from Example 1 is that the raw material used is isophthalaldehyde (structure Figure 4 C, 2.7 mg, 0.02 mmol), terephthalaldehyde (structure Figure 4 A, 10.7 mg, 0.08 mmol) and N, N, N', N'-tetrakis (p-aminophenyl) p-phenylenediamine (structure Figure 4 B, 23.6 mg, 0.05 mmol) and named TpaIda-2DCOF (yield 93%). The structure of the obtained TpaIda-2DCOF is shown below:

[0053]

[0054] TpaIda-2DCOF is the structure of the material obtained in Example 2, which is a distorted kgm topology structure, with irregular porous structure.

[0055] Example 3: Preparation of 1D covalent organic framework

[0056] The difference from Example 1 is that the raw materials used are: m- phthalaldehyde (structure is Figure 4 C, 13.4 mg, 0.10 mmol), N, N, N', N'-tetrakis (p- aminophenyl) p-phenylenediamine (structure is Figure 4 B, 23.6 mg, 0.05 mmol) synthesis, named Ida-1DCOF (yield 95%). According to the theory of reticular chemistry, the above two raw materials with symmetry are used for reaction, and the constructed COF is a one-dimensional strip structure. The structure of the obtained material is as follows:

[0057]

[0058] Ida-1DCOF is the structure of the material obtained in Example 3, which is a one-dimensional strip structure with 4c-sql topology structure, with single pore characteristics, and the strips are staggered and stacked.

[0059] Example 4: Preparation of IdaTpa-1DCOF

[0060] The difference from Example 1 is that the raw materials used are: p- phthalaldehyde (structure is Figure 4 A, 2.7 mg, 0.02 mmol), m-phthalaldehyde (structure is Figure 4 C, 10.7 mg, 0.08 mmol) and N, N, N', N'-tetrakis (p- aminophenyl) p-phenylenediamine (structure is Figure 4 B, 23.6 mg, 0.05 mmol) synthesis, named IdaTpa-1DCOF (yield 90%).

[0061]

[0062] IdaTpa-1DCOF is the structure of the material obtained in Example 4, which is a distorted 4c-sql topology structure, with irregular porous structure.

[0063] Example 5:

[0064] The difference from Example 1 is that the raw materials used are: the reaction solvent is a mixed solution of tri-methyl benzene and cyclohexene in a volume ratio of 1:1. The constant temperature heating is heated at 100℃ for 48h. The concentration of the acetic acid aqueous solution used is 5mol / L, and the acetic acid aqueous solution addition is 0.1ml. After washing, Soxhlet extraction for 20 hours, vacuum drying at 60℃.

[0065] Example 6:

[0066] The difference from Example 1 is that the raw materials used are: the reaction solvent is a mixed solution of trimethylbenzene and hexacyclopenta ...

[0067] By adjusting the ratio of terephthalaldehyde (monomer A) and isophthalaldehyde (monomer C), this method modulates the micromorphology of the COF through a three-component, one-pot process, altering the pore size distribution and achieving a controlled transition from a two-dimensional COF to a one-dimensional COF. This results in a multicomponent COF with adjustable morphology, gradient dimensionality, high reduction activity, and high selectivity. Compared to a two-component COF, the three-component COF exhibits locally irregular topology and optimized electronic properties, and the two-dimensional / one-dimensional interlaced structure significantly improves the mass transfer efficiency and reduction performance of the adsorbate.

[0068] According to the network chemistry theory, when the reaction raw materials have the symmetry of monomer A+B, the structure of the resulting material is a two-dimensional network structure, and when the reaction raw materials have the symmetry of monomer C+B, the resulting material is a one-dimensional strip structure. This difference is due to the fact that linear building units and high-symmetry building blocks are not restricted by steric hindrance when forming COFs, and are more easily transferred along the entire edge to the two-dimensional planar framework. However, due to their inherent angle restrictions, non-linear linking blocks (such as 120°) usually lead to non-edge-source transmission of COFs topological structures when constructing COFs, thereby producing specific strip-shaped or linear frameworks. When the reaction raw materials are monomers B+A+C, when the amount of C is small, the structure of the resulting product is similar to that of the product obtained by A+B; when the amount of A is small, the structure of the resulting product is similar to that of the product obtained by B+C.

[0069] When the reaction raw materials are monomers A+B, the obtained structure is a nanosheet stacking structure ( Figure 2 c); When B+C is used, it is a short nanorod structure ( Figure 2 b) When the reaction raw materials are monomers A+B+C, when the amount of C is small, the material morphology is spherical or ellipsoidal; when the amount of A is small, the material has a soft ribbon-like structure. By adjusting the ratio of the reaction raw materials used, the morphology and pore structure of the product material can be effectively controlled.

[0070] Test Case 1: Study on the Recovery Performance of Covalent Organic Frameworks for Gold

[0071] First, a purchased 1g / L gold standard stock solution (sodium chloroaurate solution) was diluted to 50-500mg / L. The covalent organic framework was then subjected to gold adsorption in a simulated solution. The solution pH was controlled between 1.0 and 10.0, and the temperature was controlled between 15° and 35°C. Each experiment was conducted three times, and the data were reported as the average.

[0072] Test method: Take an aqueous solution of gold with different concentrations (20-500 mg / L), adjust it to a pH of 1.0-10.0 with NaOH and HCl, respectively, add 2 mg of the material powder obtained in each example, and use a constant temperature oscillator to oscillate at 25°C for 24 hours. After filtering with a 0.22 μm filter head, the gold concentration in the filtrate is measured using an inductively coupled plasma emission spectrometer to calculate the adsorption capacity of the covalent organic framework for gold ions.

[0073] serial number Implementation of pH Adsorption capacity Simulated solution composition Example 1 2.0 2980mg / g <![CDATA[仅含有AuCl4 - ]]> Example 2 2.0 2650mg / g <![CDATA[仅含有AuCl4 - ]]> Example 3 2.0 3650mg / g <![CDATA[仅含有AuCl4 -- ]]> Example 4 2.0 3210mg / g <![CDATA[仅含有AuCl4 - ]]>

[0074] Test Example 2: Study on the Selective Performance of Covalent Organic Frameworks for Gold

[0075] The selective adsorption of covalent organic frameworks on a variety of metal ions: Pd 2+ , Pt 4+ 、Ba 2+ , K + 、Na + , Ca 2+ 、Co 2+ 、Fe 3+ Mg 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ 、Mn 2+ 、Hg 2+ , Pb 2+ 、Al 3+ and Cd 2+ Adsorption experiments were carried out under the same conditions.

[0076] First, prepare the solution containing the interfering metal ions as shown in the table below, 3+ The solution contains Au 3+ The concentration was 95 mg / L, the concentration of each interfering metal ion in the solution was 50 mg / L, and the pH of the resulting simulated solution was 2.0. After taking 4 portions of the simulated solution at 20 mL / portion, 2 mg of the material obtained in Examples 1 to 4 was added to each portion of the simulated solution. The mixture was shaken at 25° C. for 24 hours using a constant temperature oscillator. The mixed solution was filtered through a 0.22 μm filter to obtain a filtrate, and the content of the remaining metal ions in the filtrate was measured using an inductively coupled plasma emission spectrometer. The adsorption capacity and removal rate of the covalent organic framework for gold and other interfering ions were calculated.

[0077]

[0078] Test Example 3: Study on the gold recovery performance of covalent organic frameworks in actual leachate

[0079] The adsorption of gold by covalent organic frameworks in complex environments was studied. The mixed leachate of circuit boards and CPUs was selected as the actual water body to investigate the gold recovery ability of covalent organic frameworks in complex environments.

[0080] First, buy discarded circuit boards and CPUs from a recycling station, cut them into small pieces, clean them, and set them aside. Then, immerse the pieces in aqua regia and stir until the gold on the surface is completely dissolved.

[0081] After the reaction, the residue and the solution are separated by filtration, and the residue is subjected to secondary leaching if necessary to increase the leaching rate.

[0082] Then, the pH of the obtained experimental solution is adjusted to 1-2 to obtain a mixed leachate of the circuit board and the CPU.

[0083] Finally, each of the above solutions was divided equally into four portions, and the materials obtained in Examples 1-4 were added to each experimental solution to recover gold. The reaction was allowed to proceed on a shaker for 24 hours. After filtration, the filtrate was measured using inductively coupled plasma emission spectrometry to measure the remaining metal ion content. The adsorption capacity and recovery rate of gold and interfering ions by the covalent organic framework were calculated.

[0084] serial number Other ion recoveries Gold recovery rate Load environment Example 1 <5％ 99.9％ Circuit board and CPU leachate Example 2 <5％ 99.9％ Circuit board and CPU leachate Example 3 <5％ 99.9％ Circuit board and CPU leachate Example 4 <5％ 99.9％ Circuit board and CPU leachate

[0085] Test Example 4

[0086] The difference from Test Example 3 is that the mixed leaching solution of the circuit board and CPU is replaced by the wafer chip leaching solution.

[0087] Test example

[0088] 1. XRD tests were performed on the materials obtained in Examples 1 to 4, and the results were as follows: Figure 1 shown.

[0089] Figure 1 The structural properties of the materials under different synthesis conditions are demonstrated. Figure 1 The black line in (a) is

[0090] Tpa-2DCOF, the material obtained in Example 1; Figure 1 The blue line in (b) is the TpaIda-2DCOF obtained in Example 2; Figure 1 The red line Ida-1DCOF in (b) is the material obtained in Example 3; Figure 1 The green line in (b) is the IdaTpa-1DCOF obtained in Example 4; the two lines in the lower half of the figure are PXRD spectra simulated by the calculation software. Figure 1 (a) The experimental curve of the upper part matches well with the fitting curve of kgm-AA stacking, Figure 1 (b) The experimental curve of the upper part matches well with the fitting curve of staggered stacking. This shows that the incorporation of a small amount of m-xylylene formaldehyde into p-xylylene formaldehyde does not change the topology of the obtained covalent organic framework (i.e. almost identical PXRD); the incorporation of a small amount of p-xylylene formaldehyde into m-xylylene formaldehyde also does not change the topology of the obtained covalent organic framework (i.e. almost identical PXRD).

[0091] 2, The materials obtained in Examples 1-4 were respectively subjected to scanning electron microscopy detection, and the obtained results are shown in Figure 2 , which shows the morphological differences of different covalent organic framework materials. The different morphologies indicate the effectiveness of the mixed monomer strategy in the synthesis. Figure 2 (a) is IdaTpa-1DCOF, the substance obtained in Example 4, which has a soft ribbon structure and has a good adsorption effect on gold elements; Figure 2 (b) is

[0092] Ida-1DCOF is the substance obtained in Example 2, which presents short nanorods. This material has more adsorption sites on the surface and can better adsorb gold elements; Figure 2 (c) is Tpa-2DCOF, the substance obtained in Example 1, which has a nanosheet stacking structure. This material has more adsorption sites on the surface and can better adsorb gold elements; Figure 2 (d) is TpaIda-2DCOF, the substance obtained in Example 3, which has a spherical or ellipsoidal structure. This material has more adsorption sites on the surface and can better adsorb gold elements. Comparing the morphologies of Tpa-2DCOF and TpaIda-2DCOF, it is found that they are not the same substance. Comparing the morphologies of Ida-1DCOF and IdaTpa-1DCOF, it is found that they are not the same substance;

[0093] 3, The material obtained in Example 3 after adsorbing gold elements was subjected to scanning electron microscopy, and the measured results are shown in Figure 3 , it can be seen that gold nanoparticles are attached to the surface of the covalent organic framework, proving that the material has excellent adsorption performance; among them, the red Au trace and the similar shape are gold nanoparticles, and the yellow circle mark is TpaIda-2DCOF. Figure 3

[0094] ​In summary, a variety of Wurster covalent organic frameworks are successfully synthesized, and their adsorption performance is systematically studied by experimental measurement and adsorption system modeling. The results show that the three-component covalent organic frameworks described in the application have excellent adsorption performance for AuCl4-, and the adsorption capacity varies with the change of the structure of the covalent organic framework. In addition, the three-component covalent organic frameworks exhibit high selectivity for AuCl4- in the presence of interfering ions, and can efficiently reduce AuCl4- to Au(0). Notably, the three-component covalent organic framework materials described in the application have low raw material cost, simple synthesis method and significantly better adsorption capacity than traditional materials. Therefore, the three-component Wurster covalent organic framework can be used as a high-performance adsorbent for treating electronic waste leachate, and has broad application prospects.

[0095] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions described in the foregoing embodiments or make equivalent replacements to some of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. Application of a Wurster-type covalent organic framework material in gold adsorption, characterized in that: The gold recovery rate is >99.9%. The structural formula of the Wurster type covalent organic framework material is any of the following:

2. The use according to claim 1, characterized in that The preparation method of Wurster type covalent organic framework material comprises the following steps: Mixing the reaction raw materials and the reaction solvent and then sonicating to obtain a mixture; Aqueous acetic acid solution was added to the resulting mixture, which was degassed by three freeze-pump-thaw cycles in a liquid nitrogen bath and heated at a constant temperature to obtain a solid; The solid obtained after Soxhlet extraction and drying is a Wurster-type covalent organic framework material; The reaction raw material combination is: monomer A+B, monomer B+C or monomer A+B+C; monomers A to C are:

3. The use according to claim 2, characterized in that The reaction solvent is a mixture of o-dichlorobenzene and n-butanol in a volume ratio of 1:1, or a mixture of trimethylbenzene and hexacyclopentasiloxane in a volume ratio of 1:1; the constant temperature heating is 100-140° C. for 48-96 hours; The concentration of the acetic acid aqueous solution used is 5-8 mol / L, and the amount of the acetic acid aqueous solution additive is 0.1-0.3 ml; The washing solvents used in Soxhlet extraction were acetone, tetrahydrofuran and n-hexane, respectively; The method further comprises: performing Soxhlet extraction on the obtained solid for 20 to 28 hours, and then vacuum drying at 60 to 80° C. to obtain the Wurster type covalent organic framework material.

4. The use according to claim 2, characterized in that When the reaction raw materials are phthalaldehyde substances and N,N,N',N'-tetrakis(p-aminophenyl)-p-phenylenediamine, the molar ratio of phthalaldehyde substances and N,N,N',N'-tetrakis(p-aminophenyl)-p-phenylenediamine is 1:0.5; When the reaction raw materials are monomer A, monomer B, and monomer C, the molar ratio of monomer B:monomer A+C is 1:

2.

5. A method for gold element adsorption recovery, characterized in that: include: In an acidic solution, the Wurster-type covalent organic framework material as claimed in claim 1 is added, the mixture is shaken and mixed, and the mixture is filtered, and the gold element is adsorbed in the obtained solid; The acidic solution is an acidic simulated solution containing gold elements or an acidic waste liquid containing gold elements.

6. The gold element adsorption recovery method according to claim 5, characterized in that: Acidic solution containing Pd 2+ , Pt 4+ 、Ba 2+ , K + 、Na + , Ca 2+ 、Co 2+ 、Fe 3+ Mg 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ 、Mn 2+ 、Hg 2+ , Pb 2+ 、Al 3+ and Cd 2+ At least one of .

7. The gold element adsorption recovery method according to claim 5, characterized in that: When the acidic simulated liquid containing gold elements is a NaAuCl4 solution with a pH value of 1.0 to 10.0, the amount of Wurster-type covalent organic framework material used is 2 mg; the initial concentration of gold elements in the acidic simulated solution is 50 to 500 mg / L; the shaking mixing condition is shaking at 25°C for 24 hours; and filtration is performed using a 0.22 μm filter head.

8. The gold element adsorption recovery method according to claim 5, characterized in that: The acidic waste liquid containing gold elements is a leaching liquid of at least one of a circuit board, a CPU, and a wafer chip.

9. The gold element adsorption recovery method according to claim 5, characterized in that: When the acidic solution is a leaching solution of a mixture of circuit boards and CPUs, the gold recovery rate is 99.9%.

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