Preparation and application of guanidinium ionic porous organic polymers for extracting gold from water

Abstract

This research focuses on the preparation and application of guanidine-based ionic porous organic polymers for gold extraction from water, belonging to the field of porous organic polymer materials. Four guanidine-based ionic covalent organic framework materials (Ionic-COF-X, X:Cl) with different counterions were synthesized by reacting ionic guanidine hydrochloride monomers as organic linkers with aromatic ring-substituted triazine derivative ligands (TFBT), followed by anion exchange. ‑ ,Br ‑ AcO ‑ and SO4 2‑ A guanidine-based porous ionic polymer material (PiP-1) was obtained by reacting an ionic guanidine hydrochloride monomer as an organic linker with an aromatic ring-substituted benzimidazole derivative ligand (BDBI). PiP-1 was then applied to the adsorption and removal of gold ions in solution. It exhibited extremely high saturation adsorption capacity, rapid adsorption kinetics, high selectivity, and recyclability, showing potential for gold adsorption in practical applications.

Description

Technical Field

[0001] This invention belongs to the field of porous organic polymer materials, specifically relating to the preparation of a novel guanidine ionic porous organic polymer material, which can be used to adsorb and remove gold ions from water. Background Technology

[0002] Gold (Au) is a rare and precious metal with extensive applications in electronics and catalysis due to its superior physicochemical properties. Separating gold from ore is a complex process, often requiring the use of highly toxic cyanide, which causes severe environmental pollution and high energy consumption (Angew. Chem. Int. Ed. 2017, 56, 9331–9335). Recovering gold from discarded electronic devices can avoid significant resource waste and contribute to environmental protection.

[0003] Traditional pyrometallurgy is energy-intensive and highly polluting. Hydrometallurgy, on the other hand, is a simpler method for recovering gold from discarded electronic devices. First, gold is leached from the devices into Au(III) ions using acid or alkali solutions. Then, it is separated and purified using methods such as co-precipitation, solvent extraction, ion exchange, and adsorption. Co-precipitation and solvent extraction are prone to secondary pollution, ion exchange is complex and costly, while adsorption is simple, low-cost, and widely used in precious metal recovery. Currently, many adsorbents, such as activated carbon and ion exchange resins, have been developed. However, these adsorbents suffer from slow adsorption kinetics, poor selectivity, and poor recyclability (Macromol. Mater. Eng. 2022, 307, 2100761). Metal-organic frameworks (MOFs) have also been used as adsorbents, but their poor water stability may lead to the leaching of metal ions and secondary pollution (Angew. Chem. Int. Ed. 2024, e202402205). Therefore, developing novel adsorbents with high selectivity, high stability, and fast adsorption kinetics is of great significance for removing gold from wastewater.

[0004] Porous organic polymers (POPs) are organic materials with regular pore structures formed by covalent bonds of light elements such as C, H, O, N, and S. They exhibit good stability and high designability, and are widely used in adsorption separation, sensing, semiconductors, catalysis, and other fields. Ionic covalent organic frameworks (iCOFs) and porous ionic polymers (PiPs), as important branches of POPs, have their positive / negative charges fixed on the framework. They adsorb and capture target ions through electrostatic interactions. Adjusting the counterion can alter their specific surface area, pore structure, and internal pore environment, resulting in high designability and making them widely used in precious metal recovery, pollutant adsorption and removal, and other fields.

[0005] However, there are currently few research reports on the application of iCOFs and PiPs materials for capturing gold ions. Guanidine's three nitrogen atoms are bonded to the central carbon atom of the cation, thus possessing a positive delocalized charge and a strong ability to bind anions. Introducing guanidine groups into the framework can effectively enhance its Au-capturing ability. Therefore, we used ionic guanidine hydrochloride as an organic linker, utilizing its charged active nitrogen... + Two types of guanidine-based ionic porous organic polymer materials were synthesized: cationic covalent organic framework materials (Ionic-COFs) and porous ionic polymers (PiP-1). Ionic-COFs exhibited extremely high gold adsorption capacity, with rapid adsorption kinetics, excellent selectivity, and reusability, and successfully and efficiently recovered gold from CPUs. This work demonstrates that Ionic-COFs can serve as a useful platform for high-performance gold recovery. Compared to Ionic-COFs, PiP-1 has a higher charge density in its framework, thus exhibiting a higher adsorption capacity. To date, there are few reports on the application of PiPs materials for gold ion capture; this invention provides new insights into the application of PiPs materials in gold recovery.

[0006] Currently, there are no research reports or patent publications at home and abroad regarding the application of guanidine ionic porous organic polymer materials in the adsorption and removal of gold ions from wastewater. Summary of the Invention

[0007] The first objective of this invention is to provide a method for synthesizing guanidine ionic porous organic polymer materials. These porous organic polymer materials can be either highly crystalline covalent organic framework materials or porous polymer materials with amorphous structures.

[0008] A second objective of this invention is to provide guanidine-based ionic porous organic polymer materials for the adsorption and removal of gold from water.

[0009] To achieve the above objectives, the technical solution adopted by the present invention specifically includes the following:

[0010] The first aspect of this invention provides a method for preparing a guanidine-based ionic covalent organic framework material, comprising the following steps:

[0011] (1) Triazine derivative ligands TFBT and triaminoguanidine hydrochloride TG with aromatic ring substitution Cl The reaction mixture was placed in a Pyrex tube, and solvent was added and ultrasonically mixed until homogeneous. Then, an aqueous solution of AcOH was added as a catalyst and ultrasonically mixed until homogeneous. The mixture was then subjected to a freeze-vacuum-thaw cycle three times and sealed under a nitrogen atmosphere. After returning to room temperature, the reaction was heated to completion under sealed conditions. The product was washed with organic solvents such as dichloromethane, 1,4-dioxane, and tetrahydrofuran, and then Soxhlet extracted overnight with solvents such as tetrahydrofuran. Finally, it was vacuum dried overnight to obtain the crude product, denoted as Ionic-COF-Cl.

[0012] Or (2) Disperse the above-obtained Ionic-COF-Cl in a saturated solution of anionic sodium salts (NaBr, Na2SO4, and CH3COONa, etc.), heat and stir to exchange Cl ions with corresponding different anions. Repeat this anion exchange process three times, filter to obtain a powdered solid, wash with deionized water and anhydrous ethanol, and vacuum dry overnight to obtain guanidine ionic covalent organic framework materials with different anion exchanges; that is, finally obtain Inoic-COF-X, where X is an anion, such as selected from anions such as Cl, Br, SO4 and AcO.

[0013] Furthermore, in step (1), TFBT and TG Cl The molar ratio is 1:1.

[0014] Furthermore, in step (1), the solvent is a mixed solvent of N,N-dimethylacetamide and o-dichlorobenzene.

[0015] Furthermore, in step (1), the solvent is a mixed solvent of N,N-dimethylacetamide and o-dichlorobenzene in a volume ratio of 1 to 9:9 to 1 (preferably 1:1).

[0016] Furthermore, in step (1), the concentration of the AcOH aqueous solution is 3 mol / L to 12 mol / L, preferably 6 mol / L.

[0017] Furthermore, in step (1), the ultrasonic time is 1 to 30 minutes, and the freezing-vacuum-thawing cycle method is as follows: the reactants are frozen with liquid nitrogen, vacuumed, and thawed with nitrogen gas.

[0018] Furthermore, in step (1), the temperature of the heating reaction is between 40 and 200°C, and the reaction time is between 1 and 10 days.

[0019] Furthermore, in step (2), the heating temperature is 20-120℃.

[0020] Furthermore, in step (2), the stirring time is 1-10 hours.

[0021] The synthetic route of this invention is as follows:

[0022]

[0023] The structure of the aromatic ring-substituted triazine derivative ligand (TFBT) is as follows:

[0024] in Represents aromatic rings, O / S / Se / N and other aromatic heterocycles, wherein the aromatic rings are benzene, biphenyl, naphthalene, anthracene, phenanthrene, etc.;

[0025] like Selected from wait.

[0026] The substituent X on Inoic-COF-X can be Br, AcO, SO4, or other anions.

[0027] The second aspect of this invention provides a study on the adsorption thermodynamics, kinetics, selectivity, and recyclability of gold by the product Ionic-COF-Cl obtained in step (1) above, comprising the following steps:

[0028] Weigh an appropriate amount of tetrachloroauric acid trihydrate (HAuCl4·H2O), dissolve it in an appropriate amount of deionized water, and prepare tetrachloroauric acid aqueous solutions with different Au(III) concentrations. The accurate initial concentration C0 of Au(III) in the prepared solutions was determined by inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0029] ①Adsorption Thermodynamics: Equal volumes of tetrachloroauric acid aqueous solutions containing different initial concentrations of Au(III) were taken and placed in separate bottles. Equal masses of Ionic-COF-Cl material were added as Au(III) adsorbent to each bottle. After adding a magnetic stir bar, the mixture was stirred at room temperature. Once adsorption equilibrium was reached, the mixture was allowed to stand. The supernatant was then drawn off using a syringe, and the mixture was filtered through a disposable water-based syringe filter. The concentration C of Au(III) in the solution after adsorption equilibrium was then determined by ICP-OES. e Calculate the equilibrium adsorption capacity q of Ionic-COF-Cl at various concentrations. e .

[0030] ②Adsorption kinetics: Take an appropriate amount of tetrachloroauric acid aqueous solution containing a certain initial Au(III) concentration, add an appropriate amount of Ionic-COF-Cl as Au(III) adsorbent, add a magnetic stir bar, and mix and stir at room temperature. At certain time intervals, extract the mixture with a syringe, filter it using a disposable water-based syringe filter, and then determine the concentration C of Au(III) in the solution at that time using ICP-OES. t Calculate the removal rate R of Au(Ⅲ) at each time point. e (%).

[0031] ③ Adsorption Selectivity: First, a mixed solution containing Au(III) and several competing metal ions such as Cu(II), Co(II), Na(I), Mg(II), K(I), Fe(III), Al(III), Ni(II), and Zn(II) was prepared. All metal ions had the same initial concentration, and the accurate concentration was determined by ICP-OES. An appropriate amount of Ionic-COF-Cl was added to the above solution as adsorbent, and the mixture was stirred at room temperature after adding a magnetic stir bar. After adsorption reached equilibrium, the solution was allowed to stand, and the supernatant was drawn off with a syringe. The mixture was filtered through a disposable syringe filter using water, and then the concentrations of Au(III) and other competing metal ions in the solution after adsorption equilibrium were determined by ICP-OES, and the removal rate R was calculated. e (%).

[0032] ④ Recycling and Regeneration: Take an appropriate amount of tetrachloroauric acid aqueous solution containing a certain initial Au(III) concentration, add an appropriate amount of Ionic-COF-Cl as Au(III) adsorbent, add a magnetic stir bar, mix and stir at room temperature, filter with a disposable syringe filter, and determine the Au(III) concentration in the solution after adsorption equilibrium by ICP-OES. Collect the adsorbent, wash with deionized water, mix the collected solid with a solution containing thiourea (1M) and HCl (1M), add a magnetic stir bar, mix and stir at room temperature, filter, wash with anhydrous ethanol, and finally vacuum dry to obtain the regenerated adsorbent. The regenerated Ionic-COF-Cl is used for the next cycle of adsorption. Calculate the removal rate R of Au(III) by Ionic-COF-Cl. e (%).

[0033] Furthermore, in step ④, the volume ratio of thiourea to HCl used is 1-9:9-1 (preferably 1:1).

[0034] A third aspect of the present invention provides the application of the product Ionic-COF-Cl obtained in step (1) above in the adsorption and removal of Au from electron waste liquid, comprising the following steps:

[0035] First, cut off the gold ends of discarded printed circuit boards and soak them in aqua regia. Then, dilute the leachate to acidity with deionized water and NaOH solution. Filter the diluted leachate to remove circuit board residue, and take a sample. Determine the metal ion concentration in the filtrate using ICP-OES. Add an appropriate amount of Ionic-COF-Cl to the filtrate, add a magnetic stir bar, mix and stir at room temperature, filter using a disposable water-based syringe filter, and determine the metal concentration in the solution after adsorption equilibrium using ICP-OES. Calculate the metal ion removal rate R of Ionic-COF-Cl. e (%).

[0036] Further, the leachate is diluted to a pH of 1 to 6, preferably 2.

[0037] A fourth aspect of the present invention provides a method for preparing a guanidine-based porous ionomer material, comprising the following steps:

[0038] (1) Aromatic ring-substituted benzimidazole derivative ligands (BDBI) and triaminoguanidine hydrochloride (TG) Cl The reactants were placed in a Pyrex tube, with the substituted aromatic rings selected from benzene, furan, thiophene, selenophene, pyridine, and other heterocyclic aromatics. Solvent was added and the mixture was ultrasonically mixed until homogeneous. Then, an aqueous solution of AcOH was added as a catalyst, and the mixture was ultrasonically mixed again. The mixture was then subjected to a freeze-vacuum-thaw cycle three times, and sealed under a nitrogen atmosphere. After returning to room temperature, the reaction was heated to completion under sealed conditions. The product was washed with organic solvents such as dichloromethane, 1,4-dioxane, and tetrahydrofuran, followed by Soxhlet extraction with a solvent such as tetrahydrofuran overnight. Finally, it was vacuum dried overnight to obtain the crude product, denoted as PiP-1.

[0039] Furthermore, in step (1), BDBI and TG Cl The molar ratio is 1.5:1.

[0040] Furthermore, in step (1), the solvent is a mixture of N,N-dimethylacetamide and mesitylene.

[0041] Furthermore, in step (1), the solvent is a mixed solvent of N,N-dimethylacetamide and mesitylene in a volume ratio of 1 to 9:9 to 1 (preferably 1:1).

[0042] Furthermore, in step (1), the concentration of the AcOH aqueous solution is 3 mol / L to 12 mol / L, preferably 6 mol / L.

[0043] Furthermore, in step (1), the ultrasonic time is 1 to 30 minutes, and the freezing-vacuum-thawing cycle method is as follows: the reactants are frozen with liquid nitrogen, vacuumed, and thawed with nitrogen gas.

[0044] Furthermore, in step (1), the temperature of the heating reaction is between 40 and 200°C, and the reaction time is between 1 and 10 days.

[0045] The synthetic route of this invention is as follows:

[0046]

[0047] The structure of the aromatic ring-substituted benzimidazole derivative ligand (BDBI) is as follows:

[0048] in Represents aromatic rings, O / S / Se / N and other aromatic heterocycles, wherein the aromatic rings are benzene, biphenyl, naphthalene, anthracene, phenanthrene, etc.;

[0049] like Selected from wait.

[0050] The substituent X on PiP-1 can be F, Cl, Br, I, or other anions.

[0051] The fifth aspect of this invention provides a study on the adsorption thermodynamics, kinetics, selectivity, and recyclability of gold by the product PiP-1 obtained in step (1) above, including the following steps:

[0052] (1) Adsorption thermodynamics: Equal volumes of tetrachloroauric acid aqueous solutions containing different initial concentrations of Au(III) were taken and placed in bottles. Equal masses of PiP-1 material were added as Au(III) adsorbents to each bottle. After adding a magnetic stir bar, the mixture was stirred at room temperature. Once adsorption equilibrium was reached, the mixture was allowed to stand. The supernatant was then drawn off with a syringe, and the mixture was filtered through a disposable water-based syringe filter. The concentration C of Au(III) in the solution after adsorption equilibrium was then determined by ICP-OES. e Calculate the equilibrium adsorption capacity (q) of PiP-1 at various concentrations. e ).

[0053] (2) Adsorption kinetics: An appropriate amount of tetrachloroauric acid aqueous solution containing a certain initial Au(III) concentration was taken, and an appropriate amount of PiP-1 was added as Au(III) adsorbent. After adding a magnetic stir bar, the mixture was stirred at room temperature. The mixture was drawn with a syringe at certain time intervals and filtered through a disposable syringe filter. Then, the concentration C of Au(III) in the solution at that time was determined by ICP-OES. t Calculate the removal rate R of Au(Ⅲ) at each time point. e (%).

[0054] (3) Adsorption Selectivity: First, a mixed solution containing Au(III) and several competing metal ions such as Cu(II), Co(II), Na(I), Mg(II), K(I), Fe(III), Al(III), Ni(II), and Zn(II) was prepared. All metal ions had the same initial concentration, and the accurate concentration was determined by ICP-OES. An appropriate amount of PiP-1 was added to the above solution as an adsorbent, and the mixture was stirred at room temperature after adding a magnetic stir bar. After adsorption equilibrium was reached, the solution was allowed to stand, and the supernatant was drawn off with a syringe. The mixture was filtered through a disposable syringe filter using water, and then the concentrations of Au(III) and other competing metal ions in the solution after adsorption equilibrium were determined by ICP-OES, and the removal rate R was calculated. e (%).

[0055] (4) Recycling and Regeneration: Take an appropriate amount of tetrachloroauric acid aqueous solution containing a certain initial Au(III) concentration, add an appropriate amount of PiP-1 as Au(III) adsorbent, add a magnetic stir bar, mix and stir at room temperature, filter with a disposable needle filter, and determine the Au(III) concentration in the solution after adsorption equilibrium by ICP-OES. Collect the adsorbent, wash with deionized water, mix the collected solid with a solution containing thiourea (1M) and HCl (1M), add a magnetic stir bar, mix and stir at room temperature, filter, wash with anhydrous ethanol, and finally vacuum dry to obtain the regenerated adsorbent. The regenerated PiP-1 is used for the next cycle of adsorption. Calculate the removal rate R of Au(III) by PiP-1. e (%).

[0056] Furthermore, in step (4), the volume ratio of thiourea to HCl used is 1-9:9-1 (preferably 1:1).

[0057] The advantages of this invention are:

[0058] 1) This invention designs and synthesizes a series of ionic covalent organic framework materials Ionic-COF-X (X = Cl, Br, SO4 and AcO) with different anions, and studies the effect of different counter anions on adsorbed gold.

[0059] 2) The saturated adsorption capacity of gold by the Ionic-COF-Cl prepared in this invention is as high as 1270.76 mg g. -1 It exhibits rapid adsorption kinetics, high selectivity, and recyclability.

[0060] 3) The Ionic-COF-Cl prepared by this invention can be applied to the recovery of gold from waste circuit boards, indicating that it can achieve effective gold recovery in practical applications.

[0061] 4) The porous ionomer PiP-1 prepared in this invention has a saturated adsorption capacity as high as 1530.9 mg / g.-1 It exhibits rapid adsorption kinetics, high selectivity, and recyclability. This invention lays an important foundation for the application of PiPs materials in the field of gold recovery. Attached Figure Description

[0062] Figure 1 Powder X-ray diffraction pattern of the guanidinium ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1;

[0063] Figure 2 The Fourier Transform Infrared (FTIR) spectrum of the guanidinium-based ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1;

[0064] Figure 3 The image shows the X-ray photoelectron spectroscopy (XPS) spectrum of the guanidinium ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1.

[0065] Figure 4 The guanidine-based ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1 13 C solid-state NMR spectrum;

[0066] Figure 5 The image shows a scanning electron microscope (SEM) image of the guanidine ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1.

[0067] Figure 6 Transmission electron microscopy (TEM) image of the guanidinium ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1;

[0068] Figure 7 Thermogravimetric analysis (TGA) curves of the guanidine ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1;

[0069] Figure 8 Nitrogen adsorption-desorption curves and pore size distribution of the guanidinium ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1;

[0070] Figure 9 Powder X-ray diffraction patterns of the guanidinium-based ionic covalent organic framework materials Ionic-COF-X (X = Cl, Br, SO4 and AcO) prepared in Examples 1 and 2;

[0071] Figure 10 The Fourier Transform Infrared (FTIR) spectra of the guanidinium-based ionic covalent organic framework materials Ionic-COF-X (X = Cl, Br, SO4, and AcO) prepared in Examples 1 and 2 are shown.

[0072] Figure 11 Nitrogen adsorption-desorption curves and pore size distribution diagrams of the guanidinium-based ionic covalent organic framework materials Ionic-COF-X (X = Cl, Br, SO4 and AcO) prepared in Examples 1 and 2;

[0073] Figure 12 The adsorption isotherms of Au(Ⅲ) for the guanidinium-based ionic covalent organic framework material Ionic-COF-X (X = Cl, Br, SO4 and AcO) prepared in Examples 1 and 2 are shown.

[0074] Figure 13 Powder X-ray diffraction patterns of gold before and after adsorption on the guanidinium-based ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1;

[0075] Figure 14 This is a TEM image of gold captured by the guanidinium ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1.

[0076] Figure 15 The XPS total spectrum and high-resolution XPS spectrum of Au 4f before and after gold capture of the guanidinium ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1 are shown.

[0077] Figure 16 The adsorption isotherm of Au(Ⅲ) on the guanidinium ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1;

[0078] Figure 17 The adsorption kinetics curve of Au(Ⅲ) on the guanidine ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1 is shown.

[0079] Figure 18 The adsorption selectivity of Au(III) for the guanidine ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1;

[0080] Figure 19 The adsorption cycle regeneration of Au(III) by the guanidine ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1;

[0081] Figure 20 The practical application of the guanidine-based ionic covalent organic framework material (Ionic-COF-Cl) prepared in Example 1 in the recycling of gold from electronic waste;

[0082] Figure 21The Fourier Transform Infrared (FTIR) spectrum of PiP-1, a guanidine-based porous ionomer material prepared in Example 4;

[0083] Figure 22 The guanidine-based porous ionomer material PiP-1 prepared in Example 4 13 C solid-state NMR spectrum;

[0084] Figure 23 The powder X-ray diffraction pattern of PiP-1, a guanidine-based porous ionomer material prepared in Example 4;

[0085] Figure 24 The image shows a scanning electron microscope (SEM) image of PiP-1, a guanidine-based porous ionomer material prepared in Example 4.

[0086] Figure 25 Transmission electron microscopy (TEM) image of PiP-1, a guanidine-based porous ionomer material prepared in Example 4;

[0087] Figure 26 Thermogravimetric analysis (TGA) curves of PiP-1, a guanidine-based porous ionomer material prepared in Example 4;

[0088] Figure 27 The nitrogen adsorption-desorption curve and pore size distribution of PiP-1, a guanidine-based porous ionomer material prepared in Example 4, are shown.

[0089] Figure 28 This is a transmission electron microscope (TEM) image of the guanidine-based porous ionomer material PiP-1 prepared in Example 4 after gold adsorption.

[0090] Figure 29 The XPS total spectrum and high-resolution XPS spectrum of Au 4f before and after gold capture of the guanidine-based porous ionomer material PiP-1 prepared in Example 4 are shown.

[0091] Figure 30 The adsorption isotherm of Au(Ⅲ) on the guanidine-based porous ionomer material PiP-1 prepared in Example 4;

[0092] Figure 31 The adsorption kinetics curve of Au(Ⅲ) for the guanidine-based porous ionomer material PiP-1 prepared in Example 4 is shown.

[0093] Figure 32 The adsorption selectivity of Au(III) for the guanidine-based porous ionomer material PiP-1 prepared in Example 4 is shown.

[0094] Figure 33 The adsorption cycle regeneration of Au(Ⅲ) by the guanidine-based porous ionomer material PiP-1 prepared in Example 4 is shown. Detailed Implementation

[0095] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0096] Example 1

[0097] The preparation method of guanidine-based ionic covalent organic framework material (labeled as Ionic-COF-Cl) synthesized from biphenyl TFBT ligands is as follows:

[0098] 0.03 mmol of 2,4,6-tris-(4-formyl-biphenyl-4-yl)-1,3,5-triazine containing biphenyl and triaminoguanidine hydrochloride (TG) Cl (0.03 mmol) was placed as the reaction component in a Pyrex tube (10 mL), and N,N-dimethylacetamide / o-dichlorobenzene (DMAc / o-DCB, v / v = 1:1, total 1.0 mL) was added as a solvent. The tube was sonicated for 10 minutes, and then 6M AcOH (0.1 mL) was added as a catalyst, followed by sonication for another 5 minutes. Then, the Pyrex tube was rapidly frozen in liquid nitrogen while nitrogen was introduced, and thawed in a nitrogen atmosphere after evacuation for two minutes. After three cycles of freezing-evacuation-thawing, the air in the Pyrex tube was completely removed, and the tube was sealed under a nitrogen atmosphere. After returning to room temperature, the tube was transferred to a vacuum drying oven and heated at 120℃~150℃ for 3~7 days, avoiding disturbance during this period. After the reaction was complete, the mixture in the Pyrex tube was filtered through filter paper and washed successively with dichloromethane, 1,4-dioxane, and tetrahydrofuran, followed by Soxhlet extraction with tetrahydrofuran for 12–48 hours. Finally, it was dried in an oven to obtain the final product as a yellow solid.

[0099] Figure 1 The XRD pattern shows that Ionic-COF-Cl has high crystallinity and a regular crystal structure, confirming that the stacking mode of Ionic-COF-Cl is AB stacking. Through... Figure 2 The infrared spectrum of Ionic-COF-Cl is given. Figure 3 The given XPS spectra and Figure 4 The given solid-state carbon NMR spectrum proves the successful formation of C=N bonds and the successful construction of organic units. Figure 5 SEM images show that Ionic-COF-Cl is in the form of nanofibers. Figure 6 TEM images show that its uniform diameter is about 100 nm and its surface is rough with a scaly structure. Figure 7 The TGA curves show that Ionic-COF-Cl has good thermal stability. Figure 8 The nitrogen adsorption-desorption curves show that the specific surface area of ​​Ionic-COF-Cl is 452.9 m². 2 g -1 The main pore size distribution is around 1.18 nm, which belongs to microporous materials.

[0100] Example 2

[0101] Using the biphenyl-containing guanidine ionic covalent organic framework material (Ionic-COF-Cl) from Example 1 above, the products synthesized through anion exchange process were labeled as Ionic-COF-Br, Ionic-COF-SO4, and Ionic-COF-AcO, respectively.

[0102] The steps are as follows:

[0103] 100 mg of Ionic-COF-Cl was dispersed in 10 mL of saturated solutions of the corresponding sodium salts (NaBr, Na2SO4, and CH3COONa), respectively. The mixture was heated and stirred at 60 °C for 5 hours. This anion exchange process was repeated three times. The resulting yellow powder was washed with deionized water and anhydrous ethanol and dried under vacuum at 100 °C overnight to obtain Ionic-COF-Br, Ionic-COF-SO4, and Ionic-COF-AcO, respectively.

[0104] Figure 9 The differences in diffraction patterns and positions of Ionic-COF-Br, Ionic-COF-AcO, and Ionic-COF-SO4 compared to Ionic-COF-Cl are negligible. Figure 10 The FTIR spectra showed that the characteristic peaks of Ionic-COFs remained almost unchanged in position and intensity before and after anion exchange. Figure 11 The BET surface areas of Ionic-COF-Cl, Ionic-COF-Br, Ionic-COF-AcO, and Ionic-COF-SO4 were 452.9, 507.5, 394.5, and 372.6 m², respectively. 2 g -1 It has microporous properties.

[0105] Example 3

[0106] The adsorption performance of Au(Ⅲ) was tested using Ionic-COF-X (X = Cl, Br, SO4 and AcO) from Examples 1 and 2 above.

[0107] Figure 12The maximum adsorption capacities of Ionic-COF-Br, Ionic-COF-AcO, and Ionic-COF-SO4 for Au(III) after anion exchange were shown to be 793.7 mg g, respectively. -1 694.4 mg g -1 and 757.6 mg g -1 . Figure 13 XRD patterns of Au(III) before and after adsorption by Ionic-COF-Cl are shown. Diffraction peaks corresponding to the gold (111), (200), (220) and (311) crystal planes appear at 38.2°, 44.4°, 64.6° and 77.6°, indicating that Ionic-COF-Cl can successfully capture gold ions and reduce them to zero-valent gold. Figure 14 The TEM image shows that gold nanoparticles are uniformly dispersed on the Ionic-COF-Cl material. Figure 15 The adsorption spectrum shows the appearance of a new characteristic peak for Au 4f, indicating that gold has been successfully captured by Ionic-COF-Cl. The intensity of the zero-valent gold characteristic peak in the XPS high-resolution spectrum of Au 4f is significantly higher than that of Au(III), indicating that most of the gold ions captured by Ionic-COF-Cl are reduced to elemental gold. Figure 16 The maximum adsorption capacity q of gold by Ionic-COF-Cl was calculated from the adsorption thermodynamic results. max It is 1270.8 mg g -1 It is superior to most materials. Figure 17 The results showed that Ionic-COF-Cl reached adsorption equilibrium in less than 20 minutes, and the removal efficiency was approximately 98% after 40 minutes, indicating that Ionic-COF-Cl can effectively remove AuCl4 from aqueous solution. - ion. Figure 18 The results show that Ionic-COF-Cl still exhibits excellent selectivity for Au(III) even in the presence of various interfering metal ions. Figure 19 The results showed that the recovery rate of Ionic-COF-Cl was above 95% in five cycles, indicating that it has good regenerability and reusability as a gold adsorbent material. Figure 20 The results show that Ionic-COF-Cl has a gold removal efficiency of over 99% in the leaching solution of waste circuit boards, making it a useful material for recovering gold from real electronic waste.

[0108] Example 4

[0109] The preparation method of the guanidine-based porous ionomer material (labeled PiP-1) synthesized from the BDBI ligand containing a benzene ring, as described above, includes the following synthesis steps:

[0110] 4,7-bis(4-formylphenyl)-1,3-dimethyl-1H-benzo[d]imidazolium-3-bromide (0.0375 mmol) containing a benzene ring and triaminoguanidine hydrochloride (TG) Cl 0.025 mmol of N,N-dimethylacetamide / mesitylene (DMAc / mesitylene, v / v = 1:1, 1.0 mL total) was added as a solvent. The mixture was sonicated for 10 minutes, and then 0.1 mL of 6M AcOH solution was added as a catalyst, followed by sonication for another 5 minutes. The Pyrex tube was then rapidly frozen in liquid nitrogen while nitrogen was introduced, and after evacuation for two minutes, it was thawed in a nitrogen atmosphere. After three cycles of freezing-evacuation-thawing, the air in the Pyrex tube was completely removed, and the tube was tightly sealed under a nitrogen atmosphere. After the reaction tube returned to room temperature, it was transferred to a vacuum drying oven and heated at 120°C–150°C for 3–7 days, avoiding disturbance during this period. After the reaction was complete, the mixture in the Pyrex tube was filtered through filter paper and washed sequentially with dichloromethane, 1,4-dioxane, and tetrahydrofuran. It was then subjected to Soxhlet extraction with tetrahydrofuran for 12–48 hours, and finally dried in an oven to obtain a yellow solid. Figure 21 The given infrared spectrum of PiP-1, Figure 22 The given solid-state carbon NMR spectrum proves that the PiP-1 material was successfully formed through imine bonds. Figure 23 The XRD pattern showed no sharp peaks in the 2-40° testing range, indicating that the PiP-1 material does not possess a crystalline structure. Combined with... Figure 24 SEM images and Figure 25 The TEM images show that the PiP-1 material has a uniform morphology and is evenly distributed, with spherical particles stacked together. Figure 26 The TGA curves show that PiP-1 material has good thermal stability. Figure 27 This indicates that the BET specific surface area of ​​PiP-1 is 80.4 m². 2 g -1 The pore size is mainly distributed at 1.36 nm, making it a typical microporous material.

[0111] Example 5

[0112] The adsorption performance of Au(Ⅲ) was tested using PiP-1 from Example 4 above.

[0113] Figure 28 TEM images show that gold nanoparticles are uniformly dispersed on the PiP-1 material. Figure 29The XPS spectrum showed a new peak corresponding to Au, indicating that Au has been adsorbed around the framework of the PiP-1 material. In addition, the XPS spectrum of Au 4f showed that the gold adsorbed by PiP-1 mainly exists as Au(0) and Au(III), further demonstrating the reduction effect of PiP-1 on Au(III). Figure 30 The adsorption thermodynamic experimental results show that the maximum saturation adsorption capacity q of PiP-1 for gold is... max It is 1519.7 mg g -1 It is superior to most porous materials currently reported. Figure 31 The results showed that PiP-1 gradually reached equilibrium in gold removal efficiency within 30 minutes, with the final gold removal efficiency exceeding 99%, indicating that it is a highly promising gold adsorbent. Figure 32 The results showed that PiP-1 had a much higher removal efficiency for Au(III) than other competing metal ions, indicating that the presence of competing metal ions had almost no effect on the process of PiP-1 specifically capturing gold. Figure 33 The results showed that after five cycles, PiP-1 achieved a gold recovery rate of over 99%, indicating that it has good regenerability and recyclability.

[0114] The above embodiments are merely examples to clearly illustrate the present invention and should not be construed as limiting the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of this invention are also within the scope of protection of this invention.

Claims

1. A method for preparing a guanidine-based ionic porous organic polymer material, characterized in that, Includes the following steps: (1) Triaminoguanidine hydrochloride TG Cl The aromatic ring-substituted triazine derivative ligand TFBT was added to the solvent and ultrasonically dispersed evenly. Then, AcOH aqueous solution was added as a catalyst and ultrasonically mixed evenly. After freezing-vacuum-thawing cycle, the reaction was carried out under sealed conditions and heated until complete. The product was filtered, washed, purified by extraction, and vacuum dried to obtain the highly crystalline guanidine ionic covalent organic framework material Ionic-COF-Cl. Or (2) Disperse the above-obtained Ionic-COF-Cl in a saturated solution of anionic sodium salt NaX, heat and stir to exchange Cl ions with different corresponding anions. Repeat this anion exchange process three times, filter to obtain a powdered solid, wash with deionized water and anhydrous ethanol, and vacuum dry overnight to obtain guanidine ionic covalent organic framework materials with different anion exchanges; that is, finally obtain Inoic-COF-X, where X is an anion, Br, SO4 and AcO anions; The structure of the aromatic ring-substituted triazine derivative ligand (TFBT) is as follows: ； in Represents aromatic rings, O / S / Se / N aromatic heterocycles, wherein the aromatic rings are benzene, biphenyl, naphthalene, anthracene, and phenanthrene.

2. As described in claim 1, characterized in that, Selected from .

3. The method according to claim 1, characterized in that: Triaminoguanidine hydrochloride (TG) Cl The guanidine-based ionic covalent organic framework material has the following structural formula, with the guanidine group serving as the linker: ； Substituent X is Cl - ,Br - AcO - SO4 2- Anions.

4. The preparation method according to claim 1, characterized in that: Triaminoguanidine hydrochloride (TG) Cl The molar ratio of the ligand TFBT to the aromatic ring-substituted triazine derivative is 1 to 10:1; Triaminoguanidine hydrochloride (TG) Cl The molar ratio of the aromatic ring-substituted benzimidazole derivative ligand BDBI to BDBI is 1 to 10:

1. The reaction solvent is a mixture of N,N-dimethylacetamide and o-dichlorobenzene, with a volume ratio of N,N-dimethylacetamide to o-dichlorobenzene of 1~9 : 9~1; The concentration of the added AcOH solution is 3 mol / L ~ 12 mol / L.

5. The preparation method according to claim 4, characterized in that: Triaminoguanidine hydrochloride (TG) Cl The molar ratio of the aromatic ring-substituted triazine derivative ligand TFBT to TFBT is 1:1; Triaminoguanidine hydrochloride (TG) Cl The molar ratio of the aromatic ring-substituted benzimidazole derivative ligand BDBI to BDBI is 2:3; The reaction solvent is a mixture of N,N-dimethylacetamide and o-dichlorobenzene, with a volume ratio of N,N-dimethylacetamide to o-dichlorobenzene of 1:

1. The concentration of the added AcOH solution was 6 mol / L.

6. The preparation method according to claim 1, characterized in that: In step (1), the ultrasonic time is 1~30 min, and the freezing-vacuum-thawing cycle method is as follows: the reactants are frozen with liquid nitrogen, vacuumed, and thawed with nitrogen gas; the sealing reaction is carried out under nitrogen atmosphere or vacuum conditions.

7. The preparation method according to claim 1, characterized in that: The reaction temperature is 40~200℃, and the reaction time is 1~10 days.

8. The preparation method according to claim 1, characterized in that: After filtration, the material was washed sequentially with dichloromethane, 1,4-dioxane, and tetrahydrofuran, then extracted with organic solvents using a Soxhlet extractor for 1–5 days, and finally vacuum dried to obtain the guanidine ionic covalent organic framework material.

9. The application of the guanidine ionic porous organic polymer material obtained by the method according to claim 1, for adsorbing and removing gold ions in solution, or for separating gold ions.

10. The application according to claim 9, characterized in that: The guanidine ionic porous organic polymer material was added to a solution containing Au(III), mixed and stirred, and the gold ions therein were adsorbed.

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