A porous organic polymer and a preparation method and application thereof

Abstract

The application discloses a kind of porous organic polymer and its preparation method and application, it is related to precious metal detection and recovery technical field.The application utilizes ETBCA and 2,5-dithiobisurea as raw material, acetic acid as catalyst, is prepared porous organic polymer by Schiff base condensation reaction.The porous organic polymer is imine linked dithiobisurea tetraphenylethene-based porous organic polymer, it has abundant pore structure and uniform distribution active site, Au 3+ Excellent adsorption performance is shown;Meanwhile, it has stable fluorescence emission characteristics in ethanol system, Au 3+ It has fluorescence quenching response.Specifically, the detection limit of porous organic polymer prepared by the application to Au 3+ Is 1.021 μM;Dark and light can be adsorbed Au 3+ , adsorption capacity can reach 969.5 mg / g, 1819.9 mg / g respectively.

Description

Technical Field

[0001] This invention relates to the field of precious metal detection and recycling technology, and in particular to a porous organic polymer, its preparation method, and its application. Background Technology

[0002] Gold (Au), a scarce and non-renewable precious metal, is widely used in electronics, aerospace, fine chemicals, and catalytic materials due to its excellent chemical stability, electrical conductivity, and catalytic activity. With the rapid development of the electronics industry, the output of electronic waste is growing exponentially. The gold content in electronic waste is far higher than in other natural ores, making it a highly valuable secondary gold resource. Therefore, efficiently recovering gold from electronic waste can alleviate the shortage of gold resources and reduce the Au content in electronic waste. 3+ The pollution it causes has significant economic value and environmental benefits.

[0003] Currently, gold recovery methods include solvent extraction, electrodeposition, ion exchange, and adsorption; gold detection methods include ultraviolet-visible spectrophotometry, fluorescence detection, and surface-enhanced Raman spectroscopy. Among these, adsorption has become an important technical route for gold recovery due to its advantages such as simple operation, low energy consumption, wide availability of materials, and suitability for enriching low-concentration gold ions. Fluorescence detection has become a popular method for detecting Au due to its fast response, high sensitivity, simple operation, and relatively low detection cost. 3+ This is an important means of [development / use]. However, most existing materials only have a single function of recycling or detection, or suffer from problems such as poor selectivity of fluorescence detection, high detection limit, and low adsorption and recovery efficiency. Furthermore, Cu [waste] is commonly found in leachate from electronic waste. 2+ Ni 2+ Multiple competing ions, including Au, can interfere with Au. 3+ The identification and enrichment of Au can reduce the accuracy of material detection and recovery efficiency. Therefore, it is necessary to develop a bifunctional material to achieve fluorescent detection of Au. 3+ The adsorption and recovery of Au is a problem that urgently needs to be solved.

[0004] Porous organic polymers (POPs) have become ideal carriers for fluorescence sensing and adsorption recovery due to their advantages such as high structural designability, high specific surface area, abundant active sites, and excellent chemical stability. However, most reported POPs materials have limited functionality and can only be used for the detection of Au. 3+ Or adsorption and recovery of Au 3+ Furthermore, existing POPs materials also exhibit complex metal ion coexistence systems with Au. 3+Insufficient selectivity, poor stability, and low recovery efficiency in leachates from highly acidic, high-salt, and complex electronic wastes. For example, the paper "Fluorescent porous organic cage with good water solubility and forratiometric sensing of gold(III) ion in aqueous solution" discloses a water-soluble fluorescent porous organic cage RCC19R, which exhibits good water dispersibility and dual-emission fluorescence signal, and can be used for Au... 3+ This biosensitive ratiometric fluorescence detection exhibits excellent selectivity in both environmental water samples and biological systems. However, this material can only be used in Au... 3+ The detection and analysis do not have Au 3+ The selective adsorption and recovery capabilities of the material are demonstrated in the paper "Three Birds with One Sulfur: Construction of Sulfur-Bridged Porous Organic Polymers for Efficient Gold Adsorption," which discloses a sulfur-bridged porous organic polymer, POP-tru. Through the synergistic effect of sulfur nano-sizing and porous structure, it achieves ultra-high gold adsorption capacity and selective recovery efficiency. However, this material lacks fluorescent detection capabilities for Au. 3+ The current capabilities are insufficient to meet the multi-functional requirements of testing before recycling.

[0005] Therefore, developing a bifunctional porous organic polymer that combines highly selective detection and adsorption recovery is of great significance for promoting the development of gold resource recovery technology. Summary of the Invention

[0006] To address the aforementioned limitations of the prior art, the present invention aims to provide a porous organic polymer, its preparation method, and its applications. This invention utilizes ETBCA and 2,5-dithiobisurea as raw materials and acetic acid as a catalyst, and prepares a porous organic polymer via a Schiff base condensation reaction. This porous organic polymer is a tetraphenylethylene-based porous organic polymer of imine-linked dithiobisurea, possessing abundant pore structures and uniformly distributed active sites, and exhibiting good adhesion to Au. 3+ It exhibits excellent adsorption performance; simultaneously, it displays stable fluorescence emission characteristics in the ethanol system, and is effective for Au. 3+ It exhibits a fluorescence quenching response and can be used for the fluorescence detection of Au. 3+ Specifically, the porous organic polymer prepared in this invention is effective against Au. 3+ The detection limit is 1.021 μM; Au can be adsorbed under both dark and light conditions. 3+ The maximum adsorption capacity can reach 969.5 mg / g and 1819.9 mg / g.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a porous organic polymer having the structural formula shown in formula (I): Formula (I).

[0008] A second aspect of the present invention provides a method for preparing the above-mentioned porous organic polymer, comprising the following steps: 4',4''',4'''',4'''''''-(ethylene-1,1,2,2-tetramethyl)tetra([1,1'-biphenyl]-4-carboxaldehyde) and 2,5-dithiobisurea were mixed and then subjected to ultrasonic treatment in N,N-dimethylacetamide to obtain a mixed suspension. Acetic acid solution was added to the mixed suspension and mixed evenly to obtain a mixed system. The mixed system was subjected to cyclic degassing treatment and then subjected to Schiff base condensation reaction under heating. After the reaction was completed, the mixture was cooled and filtered to collect the solid. After washing and drying, a porous organic polymer was obtained, denoted as P1.

[0009] Preferably, the ratio of 4',4''',4'''',4''''''-(ethylene-1,1,2,2-tetramethyl)tetra([1,1'-biphenyl]-4-carboxaldehyde), 2,5-dithiobisurea and N,N-dimethylacetamide is (0.06-0.10) mmol : (0.10-0.20) mmol : 2 mL.

[0010] Furthermore, the ratio of 4',4''',4'''',4'''''''-(ethylene-1,1,2,2-tetramethyl)tetra([1,1'-biphenyl]-4-carboxaldehyde), 2,5-dithiobisurea and N,N-dimethylacetamide is 0.08 mmol:0.16 mmol:2 mL.

[0011] Preferably, the concentration of the acetic acid solution is 5 mol / L to 7 mol / L.

[0012] Preferably, the volume ratio of N,N-dimethylacetamide to acetic acid solution is (8-12):1.

[0013] Furthermore, the volume ratio of N,N-dimethylacetamide to acetic acid solution is 10:1.

[0014] Preferably, the ultrasonic treatment time is 5-15 min.

[0015] Preferably, the mixed system is subjected to three cycles of degassing; the cycle of degassing is a freezing-evacuation-thawing cycle of degassing.

[0016] Preferably, the heating temperature is 140-160 ℃ and the Schiff base condensation reaction time is 24-72 h.

[0017] Preferably, the washing procedure is as follows: the solid is washed 2-3 times in sequence with tetrahydrofuran, N,N-dimethylacetamide and dimethyl sulfoxide.

[0018] Preferably, the drying temperature is 50-70℃ and the drying time is 12h.

[0019] A third aspect of the present invention provides the above-mentioned porous organic polymer for the fluorescence detection of Au. 3+ and / or adsorption recovery of Au 3+ Applications in [the context of the text].

[0020] Preferably, the adsorption and recovery of Au 3+ The specific application is as follows: the above-mentioned porous organic polymer is used as an adsorbent to recover Au element from electronic waste.

[0021] Furthermore, the specific steps for recovering Au from electronic waste using porous organic polymers are as follows: Pyridine and N-bromosuccinimide were mixed and dispersed in deionized water to obtain an extract; electronic waste was soaked in the extract for 8-12 days, and the supernatant was collected after centrifugation to obtain an electronic waste leachate; the above porous organic polymer was added to the electronic waste leachate and stirred at room temperature for 12 hours for adsorption. The electronic waste is a discarded computer CPU; the ratio of pyridine, N-bromosuccinimide and deionized water is (45-55) µL: (150-250) mg: 100 mL; the ratio of porous organic polymer and electronic waste leachate is (4-6) mg: 30 mL.

[0022] The beneficial effects of this invention are: 1. This invention utilizes ETBCA and 2,5-dithiobisurea as raw materials and acetic acid as a catalyst to prepare a porous organic polymer P1 via a Schiff base condensation reaction. This porous organic polymer P1 is a tetraphenylethylene-based porous organic polymer of imine-linked dithiobisurea, which can be used in Au... 3+ Fluorescence detection and efficient adsorption. Specifically, The porous organic polymer P1 possesses an abundant pore structure and uniformly distributed active sites, which are beneficial for Au. 3+ It exhibits excellent adsorption performance and can be used for the adsorption and recovery of Au. 3+ Meanwhile, it exhibits stable fluorescence emission characteristics in the ethanol system, and is effective for Au. 3+ It exhibits a fluorescence quenching response and can be used for the fluorescence detection of Au. 3+ .

[0023] 2. The porous organic polymer P1 obtained by this invention can be directly used in acidic leachate of electronic waste, in Ni 2+ Cu 2+ Under coexistence conditions, still for Au 3+ It exhibits excellent selectivity. Specifically, it can be used to recover Au from leachate of electronic waste. 3+ At that time, Au 3+ Recovery rate higher than 97%, residual Au 3+ The concentration is below 0.1 ppm. Furthermore, the porous organic polymer P1 can be recycled more than 8 times while maintaining stable adsorption performance, demonstrating good potential for industrial applications.

[0024] 3. The porous organic polymer P1 prepared by this invention exhibits high thermal stability and excellent chemical stability, and can be regenerated multiple times, meeting the requirements of green and sustainable development. Furthermore, the regular structure of the porous organic polymer P1 provides a new approach for the design of highly selective adsorption porous organic polymers. Attached Figure Description

[0025] Figure 1 Synthetic route diagram of porous organic polymer P1; Figure 2 FT-IR spectrum of porous organic polymer P1 prepared in Example 1; Figure 3 The porous organic polymer P1 prepared in Example 1 13 C NMR spectrum; Figure 4 Scanning electron microscope image and SEM-EDS mapping image of the porous organic polymer P1 prepared in Example 1; Figure 5 N2 adsorption-desorption isotherm of porous organic polymer P1 prepared in Example 1; Figure 6 Pore ​​size distribution diagram of porous organic polymer P1 obtained in Example 1; Figure 7 Thermogravimetric analysis curve of porous organic polymer P1 prepared in Example 1; Figure 8 The porous organic polymer P1 prepared in Example 1 reacts with different concentrations of Au. 3+ The fluorescence emission spectrum; Figure 9 The porous organic polymer P1 prepared in Example 1 is effective against Au. 3+ Linear fitting curve of fluorescence response; Figure 10 Comparison of fluorescence intensity of porous organic polymer P1 prepared in Example 1 under interference from multiple coexisting metal ions; Figure 11The porous organic polymer P1 prepared in Example 1 exhibits its effect on Au under darkness and light conditions. 3+ Adsorption kinetics curves; Figure 12 The porous organic polymer P1 prepared in Example 1 is effective against Au. 3+ Fitted plot of Langmuir adsorption isotherms; Figure 13 Example 1: The porous organic polymer P1 prepared adsorbs Au 3+ Au 4f XPS image afterward; Figure 14 Example 1: The porous organic polymer P1 prepared in Example 1 affects Au in CPU leachate. 3+ Ni 2+ Cu 2+ Comparison chart of recycling efficiency; Figure 15 Bar chart showing the cyclic performance of the porous organic polymer P1 prepared in Example 1, based on an adsorption-desorption-regeneration test. Detailed Implementation

[0026] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0027] As described in the background section, most existing porous organic polymers can only be used to detect Au. 3+ Or adsorb Au 3+ Few porous organic polymers can simultaneously detect and adsorb Au. 3+ Furthermore, existing porous organic polymers have shown effectiveness in adsorbing and recovering Au. 3+ At that time, there was still a problem with Au. 3+ The problems include poor selectivity and poor stability.

[0028] Based on this, the present invention provides a porous organic polymer P1, the synthesis process of which is as follows: Figure 1 As shown. Specifically, it uses 4',4''',4''''',4'''''''-(ethylene-1,1,2,2-tetramethyl)tetra([1,1'-biphenyl]-4-carboxaldehyde) (ETBCA) as the conjugated backbone and fluorescent unit, and 2,5-dithiobisurea as the electron acceptor and Au. 3+The specific recognition site undergoes a Schiff base condensation reaction under the proton catalysis of acetic acid (catalyst); during the reaction, the aldehyde group (-CHO) on the ETBCA molecule undergoes a nucleophilic addition-dehydration reaction with the amino group (-NH2) of 2,5-dithiobisurea to form a C=N imine bond, thus producing a porous organic polymer P1; this porous organic polymer P1 is a tetraphenylethylene-based porous organic polymer of imine-linked dithiobisurea.

[0029] The porous organic polymer P1 prepared by this invention exhibits a popcorn-like microstructure with uniform distribution of C, N, and S elements; its BET specific surface area is 48.53 m². 2 / g, with an average pore size of 23.4nm, possessing abundant mesoporous structure. The porous organic polymer P1 itself has a mesoporous structure of 23.4nm, which can be Au 3+ Providing diffusion channels is beneficial to Au 3+ Diffusion penetrates into the porous organic polymer P1, increasing Au. 3+ The probability of contact with internal N / S active sites. Furthermore, the charge density of the dithiobisurea structural region in the porous organic polymer P1 is significantly negative, and local orbital localization analysis confirms that sulfur atoms possess a larger lone electron cloud, which can interact with Au. 3+ Strong intermolecular interactions are formed, leading to stable adsorption. Simultaneously, the tetraphenylethylene conjugated framework in the porous organic polymer P1 exhibits high spatial separation of holes and electrons and low charge recombination after photoexcitation, generating a large number of photogenerated electrons to participate in the reduction reaction. This allows the coordinated adsorbed Au to be effectively absorbed. 3+ The Au particles are reduced to elemental Au and deposited inside the pores, further enhancing the material's Au trapping capabilities. 3+ Therefore, the adsorption capacity under light conditions is much higher than that in a dark environment.

[0030] Specifically, the porous organic polymer prepared by this invention is effective against Au. 3+ It exhibits excellent adsorption performance, with a maximum gold adsorption capacity of 969.5 mg / g under dark conditions and a maximum adsorption capacity of 1819.9 mg / g under visible light irradiation. Within 3 hours, Au... 3+ It achieves a removal rate exceeding 99%, exhibiting advantages such as rapid adsorption rate, high capacity, and excellent selectivity. The adsorption process conforms to both the pseudo-second-order kinetic model and the Langmuir monolayer adsorption model.

[0031] The porous organic polymer P1 prepared in this invention uses a tetraphenylethylene conjugated framework as the fluorescent luminescent unit, and is enriched with negatively charged 2,5-dithiobisurea fragments and abundant lone electron orbitals of sulfur atoms, which can react with [AuCl4]. - Strong intermolecular interactions are generated. After the two combine, the electrons of the excited-state polymer backbone shift towards [AuCl4]. -Photoinduced electron transfer (PET) occurs, consuming charge carriers originally intended for fluorescence radiation, thus causing fluorescence quenching. Specifically, the porous organic polymer P1 has an excitation wavelength of 464 nm and an emission wavelength of 537 nm in an ethanol system, and can be used for fluorescence detection of Au based on the aforementioned fluorescence quenching effect. 3+ The detection limit of the porous organic polymer of the present invention is 1.021 μM; and it still exhibits good resistance to Au in metal ion coexistence systems. 3+ It exhibits high selectivity in recognition, strong anti-interference ability, and is suitable for rapid detection of Au³⁺ in complex systems.

[0032] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0033] The experimental materials used in the embodiments of this invention are all conventional experimental materials in the art and can be purchased through commercial channels.

[0034] In this invention, the CAS number of 4',4''',4'''',4''''''-(ethylene-1,1,2,2-tetramethyl)tetra([1,1'-biphenyl]-4-carboxaldehyde) (ETBCA) is 1624970-54-2; 2,5-dithiobisurea, also known as 2,5-dithiodiurea, has the CAS number 142-46-1; and N,N-dimethylacetamide has the CAS number 127-19-5.

[0035] Example 1: Preparation of porous organic polymers 0.08 mmol of 4',4''',4'''',4''''''-(ethylene-1,1,2,2-tetramethyl)tetra([1,1'-biphenyl]-4-carboxaldehyde) (ETBCA) and 0.16 mmol of 2,5-dithiobisurea were mixed and added to a pressure-resistant Pyrex reaction tube. Then, 2 mL of N,N-dimethylacetamide (DMAc) was added to the pressure-resistant Pyrex reaction tube, and the mixture was sonicated for 10 min to obtain a mixed suspension. Add 0.2 mL of 6 mol / L acetic acid solution as a catalyst to the above mixed suspension, mix thoroughly to obtain a mixed system; immerse the pressure-resistant Pyrex reaction tube containing the mixed system in liquid nitrogen for freezing and evacuation to 10 °C. -3 Below Pa, thaw, and repeat the above freezing-evacuation-thawing cycle three times to remove oxygen from the pressure-resistant Pyrex reaction tube; After sealing the reaction tube, it was placed at 150℃ for 48 h to carry out the Schiff base condensation reaction. After the reaction was completed, it was cooled to room temperature and filtered to collect the yellow solid. The solid was washed three times successively with tetrahydrofuran, N,N-dimethylacetamide and dimethyl sulfoxide to remove unreacted monomers, oligomers and impurities. Finally, the washed solid was dried at 60℃ for 12 h to constant weight to obtain a porous organic polymer, denoted as porous organic polymer P1, whose structural formula is shown below: The porous organic polymer P1 obtained in this embodiment is a yellow powder with a yield of 79%.

[0036] Experimental Example 1: Structural Characterization The porous organic polymer P1 prepared in Example 1 was characterized structurally, and the results are as follows: Figures 2-6 As shown.

[0037] To verify the functional groups and bonding mode, FT-IR analysis was performed on the porous organic polymer P1, and the results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the porous organic polymer P1 at 3393 cm⁻¹ -1 A peak of NH stretching vibration appears at 1630 cm⁻¹. -1 A strong C=N stretching vibration peak appears at 1698 cm⁻¹. -1 The characteristic peak of the C=O group of the aldehyde group has basically disappeared. The above results prove that the aldehyde group in the monomer ETBCA and the amino group in 2,5-dithiobisurea undergo complete Schiff base condensation to form an imine-linked polymer backbone.

[0038] To verify the carbon framework structure, the porous organic polymer P1 was subjected to solid-state reaction. 13 C NMR analysis, results are as follows Figure 3 As shown. By Figure 3 It can be seen that the peaks at 141, 131, and 127 ppm are characteristic peaks of the aromatic ring carbon of the TPE unit, and the peak at 160 ppm is the carbon signal of the imine bond (C=N), which is consistent with the theoretical structure.

[0039] To reveal the morphology and elemental distribution, SEM-EDS analysis was performed on the porous organic polymer P1. The results are as follows: Figure 4 As shown. By Figure 4 It can be seen that the porous organic polymer P1 exhibits a uniform popcorn-like morphology with no obvious agglomeration; and the C, N, and S elements are uniformly distributed in the porous organic polymer P1 without element segregation.

[0040] To illustrate the pore structure parameters, N2 adsorption-desorption tests were performed on the porous organic polymer P1, and the results are as follows: Figures 5-6 As shown. By Figure 5 and Figure 6 It can be seen that the isotherm of the porous organic polymer P1 is type IV, which proves that it has a rich pore structure inside. Its specific surface area is measured to be 48.53 m². 2 / g, the average pore size was calculated to be 23.4nm using the NLDFT method, indicating sufficient internal porosity, which is beneficial for Au. 3+ Diffusion and adsorption.

[0041] To demonstrate thermal stability, the porous organic polymer P1 was analyzed by thermogravimetric analysis (TGA), specifically by heating it from 30°C to 800°C at a rate of 10°C / min under N2 conditions. The results are as follows: Figure 7 As shown. By Figure 7 It can be seen that the porous organic polymer P1 has no significant mass loss before 550℃, has a high thermal decomposition temperature, excellent thermal stability, and can adapt to harsh industrial environments.

[0042] Experimental Example 2: Fluorescence Detection The fluorescence response behavior of the porous organic polymer P1 prepared in Example 1 was tested, and the specific steps are as follows: (1) Disperse 0.6g of the porous organic polymer P1 prepared in Example 1 in 1L of anhydrous ethanol to obtain the dispersion to be tested; set the excitation wavelength of the instrument to 464nm and collect the fluorescence emission signal at 537nm; first collect the fluorescence emission spectrum of the dispersion to be tested (0μM), and then add Au of different concentrations to the dispersion to be tested in a gradient. 3+ Solutions (1 μM, 5 μM, 10 μM, 15 μM, 20 μM, 30 μM, 40 μM, 50 μM, KAuCl4 solution), after mixing, were used to determine different concentrations of Au. 3+ The fluorescence emission spectra of the solution were recorded, along with the fluorescence emission spectra of Au at different concentrations. 3+ The fluorescence intensity corresponding to the solution, and the fluorescence intensity generated vary with Au. 3+ Concentration change curve, results as follows Figure 8 and Figure 9 As shown.

[0043] (2) Take another sample of the above-mentioned dispersion and add 1 mL of 20 μM solutions of different metal ions (K+, K ... + Na + Ba 2+ Zn 2+ Ca 2+ Mn 2+ Mg 2+ Cu 2+ Ni 2+ Co 2+ Fe 2+ Fe 3+ Au 3+A blank control group was set up with the test dispersion without metal ion solution; the fluorescence signal of each group was detected, and the results are as follows: Figure 10 As shown.

[0044] Depend on Figure 8 It can be seen that the porous organic polymer P1 prepared in this invention has a significant fluorescence emission peak at 537 nm; and the fluorescence intensity of the porous organic polymer P1 increases with Au. 3+ Increased concentration resulted in significant fluorescence quenching behavior.

[0045] Depend on Figure 9 It can be seen that the porous organic polymer P1 prepared in this invention has a detection linear range of 0-50 μM and a detection limit of 1.021 μM, which indicates that the porous organic polymer P1 has good detection linearity for Au. 3+ It exhibits high sensitivity.

[0046] Depend on Figure 10 It can be seen that, with the addition of Au 3+ It can significantly reduce the fluorescence intensity of porous organic polymer P1, producing significant fluorescence quenching; except for Au 3+ In addition, the fluorescence intensity of the system remained essentially the same as that of the blank group when other added metal ions were present, meaning that the interfering ions hardly caused any significant changes in the fluorescence signal. This indicates that the porous organic polymer P1 prepared in this invention can still specifically recognize Au in a multi-metal coexistence environment. 3+ .

[0047] In summary, the porous organic polymer P1 prepared by this invention has the effect of improving the performance of Au. 3+ It exhibits high sensitivity and high selectivity.

[0048] Experimental Example 3: Adsorption Performance Testing Using the porous organic polymer P1 prepared in Example 1 to treat Au 3+ An adsorption test was conducted. The specific steps are as follows: (1) Prepare Au solution with a concentration of 100 ppm 3+ Solution (KAuCl4); Accurately weigh 10 mg of porous organic polymer P1 and add it to 50 mL of the above Au solution. 3+ An adsorption system is formed in the solution. The adsorption system is divided into two groups: one placed under dark conditions and the other under visible light irradiation. In both groups, parameters such as material dosage, reaction temperature, and sampling time are kept consistent.

[0049] Subsequently, samples were taken at different adsorption times, and the solid and liquid phases were separated by filtration. The Au content in the liquid phase was then tested. 3+ Concentration, calculation of Au in the adsorption system under dark and light conditions. 3+ Removal rate, results as follows Figure 11 As shown. Among them, Au 3+ Removal rate = [(C0-C e ) / C0]×100%; In the formula, C0 represents Au before adsorption. 3+ Au in solution 3+ Concentration; C e Au at different adsorption times 3+ The adsorption equilibrium concentration.

[0050] (2) Isothermal adsorption test: Prepare Au at different initial concentrations 3+ Solutions (50, 100, 200, 300, 400, 500, 600, 700, 800 ppm) were added to 10 mL of Au solutions of different concentrations. 3+ 2 mg of porous organic polymer P1 was added to the solution, and adsorption occurred under darkness and visible light irradiation, respectively. Once adsorption equilibrium was reached, the solid and liquid phases were separated by filtration, and the Au content in the liquid phase was detected. 3+ Concentration and calculate equilibrium adsorption capacity Q e Linear fitting of the Langmuir isotherm adsorption model was performed, and the fitting curve was obtained. The results are as follows: Figure 12 As shown.

[0051] Among them, the equilibrium adsorption amount Q e The formula for calculating Q is: e =[(C0-C e [V / m]; In the formula, C0 represents Au before adsorption. 3+ Au in solution 3+ Concentration; Ce is Au in the liquid phase after adsorption equilibrium. 3+ Concentration; V is Au 3+ The volume of the solution; m is the mass of the porous organic polymer P1.

[0052] Depend on Figure 11 It can be seen that the porous organic polymer P1 has a significantly faster adsorption rate under light conditions, with Au adsorption within 3 hours. 3+ The removal rate is >99%, and the adsorption kinetics fits a pseudo-second-order kinetic model. Figure 12 It can be seen that the adsorption data fits better with the Langmuir model. The maximum adsorption capacity of porous organic polymer P1 is 969.5 mg / g under dark conditions and can reach 1819.9 mg / g under light conditions.

[0053] To reveal the effect of porous organic polymer P1 on Au 3+ The adsorption binding state of Au 3+ The porous organic polymer P1 was then subjected to Au 4f XPS analysis, and the results are as follows: Figure 13 As shown. By Figure 13It can be seen that the Au 4f characteristic signal appears at the peaks of 83.8 eV and 87.5 eV, indicating that the gold element was successfully adsorbed onto the polymer surface.

[0054] Experimental Example 4: The porous organic polymer P1 prepared in Example 1 was used to selectively recover Au from electronic waste (CPU chips). The specific steps are as follows: 50 µL of pyridine and 200 mg of N-bromosuccinimide were mixed and dispersed in 100 mL of deionized water to obtain an extract. Waste Intel CPU chips were immersed in the extract and allowed to stand at room temperature for 10 days. After centrifugation, solid residues were removed, and the supernatant was collected to obtain an Au-containing extract. 3+ Ni 2+ Cu 2+ Leachate from electronic waste; Five mg of the porous organic polymer P1 prepared in Example 1 was weighed and added to three portions of electronic waste leachate, respectively. The pH of the system was adjusted to 3.0, 5.0, and 7.0 using a hydrochloric acid / sodium hydroxide buffer system. Adsorption was carried out by stirring under light at room temperature for 12 hours. After adsorption was completed, the mixture was filtered, and the filtrate was collected. The residual concentration of metal ions in the filtrate was determined by ICP-MS, and the recovery rate (%) was calculated. The results are as follows: Figure 14 As shown.

[0055] Where, recovery rate (%) = [(C0-C e ) / C0]×100%; In the formula, C0 represents Au before adsorption. 3+ Au in solution 3+ Concentration; C e Au after adsorption 3+ The adsorption equilibrium concentration.

[0056] Depend on Figure 14 It can be seen that, within the pH range of 3.0-7.0, the porous organic polymer P1 has a positive effect on Au. 3+ Recovery rates were all >97%, and Au in the filtrate was <97%. 3+ Residual concentration <0.1 ppm. Under the same conditions, the material's effect on Ni... 2+ Cu 2+ The adsorption recovery rate remained at an extremely low level, indicating that the porous organic polymer P1 has excellent adsorption selectivity for gold ions over a wide pH range.

[0057] Experiment 5: Stability Test At room temperature, 10 mg of porous organic polymer P1 was added to 50 mL of 100 ppm Au solution. 3+The solid was placed in a solution (KAuCl4 solution) and shaken at a constant speed until adsorption equilibrium was reached. After filtration, the solid and supernatant were separated. The separated solid was then soaked overnight in an eluent prepared from a mixture of 0.1 mol / L thiourea and 0.1 mol / L hydrochloric acid for Au adsorption. 3+ The adsorption-desorption process was repeated eight times. After each adsorption, the Au content in the supernatant was determined by ICP-MS. 3+ Concentration, calculate the amount of adsorption Q at each equilibrium. e The result is as follows Figure 15 As shown.

[0058] The results are as follows Figure 15 As shown, after eight adsorption-desorption cycles, the cyclic equilibrium adsorption capacity of the porous organic polymer P1 only decreased slightly. The results indicate that the porous organic polymer P1 prepared in this invention maintains stable performance after eight cycles, demonstrating good recyclability and industrial application potential.

[0059] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. Porous organic polymers in the fluorescence detection of Au 3+ and / or adsorption recovery of Au 3+ The application of this is characterized by, The structural formula of the porous organic polymer is shown in formula (I): Equation (I); The porous organic polymer is prepared by the following method: 4',4''',4'''',4''''''-(ethylene-1,1,2,2-tetramethyl)tetra([1,1'-biphenyl]-4-carboxaldehyde) and 2,5-dithiobisurea were mixed and then subjected to ultrasonic treatment in N,N-dimethylacetamide to obtain a mixed suspension. Acetic acid solution was added to the mixed suspension and mixed evenly to obtain a mixed system. The mixed system was subjected to cyclic degassing treatment and then subjected to Schiff base condensation reaction under heating. After the reaction was completed, the mixture was cooled and filtered to collect the solid. After washing and drying, a porous organic polymer was obtained.

2. The application as described in claim 1, characterized in that, The ratio of 4',4''',4''''',4''''''-(ethylene-1,1,2,2-tetramethyl)tetra([1,1'-biphenyl]-4-carboxaldehyde), 2,5-dithiobisurea and N,N-dimethylacetamide is (0.06-0.10) mmol : (0.10-0.20) mmol : 2 mL.

3. The application as described in claim 1, characterized in that, The concentration of the acetic acid solution is 5 mol / L-7 mol / L; the volume ratio of N,N-dimethylacetamide to acetic acid solution is (8-12):

1.

4. The application as described in claim 1, characterized in that, The heating temperature is 140-160℃, and the Schiff base condensation reaction time is 24-72h.

5. The application as described in claim 1, characterized in that, The specific washing procedure is as follows: the solid is washed 2-3 times in sequence with tetrahydrofuran, N,N-dimethylacetamide and dimethyl sulfoxide; the drying temperature is 50-70℃ and the drying time is 12h.

6. The application as described in claim 1, characterized in that, The adsorption and recovery of Au 3+ The specific application is as follows: using the porous organic polymer described in claim 1 as an adsorbent to recover Au elements from electronic waste; The specific steps are as follows: pyridine and N-bromosuccinimide are mixed and dispersed in deionized water to obtain an extract; electronic waste is soaked in the extract for 8-12 days, and the supernatant is collected after centrifugation to obtain an electronic waste leachate; the porous organic polymer described in claim 1 is added to the electronic waste leachate and stirred at room temperature for 12 hours for adsorption.

7. The application as described in claim 6, characterized in that, The electronic waste is a discarded computer CPU; the ratio of pyridine, N-bromosuccinimide and deionized water is (45-55) µL: (150-250) mg: 100 mL; the ratio of the porous organic polymer and the electronic waste leachate according to claim 1 is (4-6) mg: 30 mL.

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