A silsesquioxane-based fluorescent porous hybrid polymer with d-a structure, its preparation and application in recycling gold

Abstract

The application provides a silsesquioxane-based fluorescent porous hybrid polymer with a D-A structure and preparation and application thereof in recycling gold. The application innovatively prepares a conjugated organic fluorescent monomer with a D-A structure by taking a cage-type silsesquioxane as a building unit, and crosslinks the two through a Heck reaction to prepare a fluorescent porous hybrid polymer (PTSC) with a D-A structure. The polymer has a large specific surface area, strong light absorption capacity, a narrow optical band gap and excellent semiconductor behavior. When the polymer is used as an Au(III) adsorbent, adsorption and photocatalytic reduction are simultaneously performed under irradiation of visible light, the adsorption performance is excellent, the adsorption efficiency can reach about 80% in 15 minutes, the maximum adsorption capacity can reach 3080 mg / g, and the polymer has good selectivity and anti-interference property, and has a good application prospect in the field of processing or recycling of precious metals.

Description

Technical Field

[0001] This invention relates to a silsesquioxane fluorescent porous hybrid polymer with a DA structure, its preparation and application in gold recovery, belonging to the fields of functional polymer material preparation, catalytic reduction and precious metal recovery technology. Background Technology

[0002] Gold is an important precious metal resource with wide applications worldwide, including medical, sensory, chemical catalysis, electronics, and jewelry manufacturing. Unfortunately, it is also a gradually depleting natural resource, and its supply is severely insufficient due to rapid scientific and technological advancements. Recycling and reusing Au(III) from gold-containing wastewater or electronic waste could not only alleviate resource shortages but also have significant economic value. Currently, Au(III) recovery methods include electrolytic separation, ion exchange, solvent extraction, membrane separation, and adsorption. Among these, adsorption is widely used due to its simple operation, good reusability, and low cost. However, relying solely on adsorption to recover Au(III) has certain limitations, such as poor selectivity, instability, and low adsorption efficiency. Therefore, the development of novel multifunctional adsorbents is essential.

[0003] In recent years, photocatalysts have become a research hotspot due to their advantages such as low energy consumption, high efficiency, and environmental friendliness. Among the many different types of photocatalysts, DA-type conjugated organic polymers, as a class of polymer-based photocatalysts with electron donors (D) and acceptors (A) as repeating units in their main chain, have advantages such as high carrier mobility, convenient band gap adjustment, tunable functionalization, and tunable porosity, because their optical band gap can be easily adjusted through the electronic structure of D and A. They have shown excellent performance in the adsorption and photocatalytic treatment or recovery of heavy metals. However, there are not many reports on the application of this type of material to the recovery of Au(III) from wastewater.

[0004] The key to designing photocatalytic materials for the photocatalytic reduction of Au(III) lies in the selection of building blocks. Cage-like silsesquioxanes, due to their ease of functionalization and highly supportive rigid conjugated three-dimensional structure, are ideal building blocks for constructing functional hybrid porous polymers, showing promising applications in adsorption, catalysis, and energy storage. In the field of photocatalysis, hybrid porous polymers prepared by crosslinking these building blocks with organic monomers possessing DA conjugated structures exhibit advantages such as large specific surface area, wide absorption range, and small optical band gap, demonstrating excellent performance in the photocatalytic degradation of organic pollutants, such as dyes and antibiotics. However, the application of these polymers in Au(III) recovery has not yet been extensively studied.

[0005] Based on the above situation, it is unique, novel and necessary to design and synthesize porous photocatalytic materials containing silsesquioxane units and study the recovery effect of Au(III) in wastewater under the synergistic effect of adsorption and photocatalytic reduction. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a silsesquioxane fluorescent porous hybrid polymer with a DA structure, its preparation, and its application in gold recovery. This invention first synthesizes a novel organic fluorescent monomer (TSC) with a DA structure, and then prepares a fluorescent porous hybrid material by reacting it with octavinylsilsesquioxane (OVS) via a Heck reaction. The resulting material exhibits a large specific surface area, strong visible light absorption, a narrow optical band gap, and excellent semiconductor properties, demonstrating superior performance in the efficient adsorption and catalytic reduction of gold ions.

[0007] The technical solution of the present invention is as follows:

[0008] A silsesquioxane fluorescent porous hybrid polymer with a DA structure has the structural unit shown in formula (I); the fluorescent porous hybrid polymer is constructed by connecting an octavinylsilsesquioxane building unit with a cage structure and an organic fluorescent monomer (TSC) with a DA structure via a bridging bond -Si-CH=CH-phenyl; the organic fluorescent monomer (TSC) with a DA structure has the structure shown in formula (II).

[0009]

[0010] The preparation method of the above-mentioned silsesquioxane fluorescent porous hybrid polymer with DA structure includes the following steps:

[0011] (1) Dissolve octavinylsilsesquioxane (OVS) with cage structure and organic fluorescent monomer (TSC) with DA structure in organic solvent, add catalyst and base, mix well and then heat to react; after the reaction is completed, cool, filter and wash to obtain solid A;

[0012] (2) The solid A obtained in step (1) is subjected to Soxhlet extraction, and the solid obtained is vacuum dried to obtain a sesquioxane fluorescent porous hybrid polymer with DA structure.

[0013] According to a preferred embodiment of the present invention, the molar ratio of the organic fluorescent monomer (TSC) with DA structure to the cage-like octavinylsilsesquioxane (OVS) in step (1) is (1-4):1, and more preferably (2-3):1.

[0014] According to the present invention, the organic solvent in step (1) is preferably N,N-dimethylformamide or 1,4-dioxane, and more preferably N,N-dimethylformamide.

[0015] According to a preferred embodiment of the present invention, the mass ratio of the cage-like octavinylsilsesquioxane (OVS) to the volume ratio of the organic solvent in step (1) is 1 g: (50-150) mL.

[0016] According to a preferred embodiment of the present invention, the catalyst in step (1) is tetrakis(triphenylphosphine)palladium or palladium acetate-ligand tris(o-methylphenyl)phosphine, more preferably palladium acetate-ligand tris(o-methylphenyl)phosphine; the molar ratio of the catalyst to the cage-like octavinylsilsesquioxane (OVS) is (0.14-0.48):1, wherein the molar number of palladium acetate-ligand tris(o-methylphenyl)phosphine is calculated based on the molar number of palladium acetate; the molar ratio of palladium acetate to tris(o-methylphenyl)phosphine in the palladium acetate-ligand tris(o-methylphenyl)phosphine is 1:(1.8-2.2).

[0017] According to a preferred embodiment of the present invention, the alkali mentioned in step (1) is one or a combination of two or more of sodium bicarbonate, potassium carbonate, and triethylamine, and is more preferably sodium bicarbonate.

[0018] According to a preferred embodiment of the present invention, the mass ratio of the alkali and the cage-like octavinylsilsesquioxane (OVS) in step (1) is (1-3):1.

[0019] According to a preferred embodiment of the present invention, the organic solvent in step (1) is N,N-dimethylformamide, the heating reaction temperature is 110-140°C, and the heating reaction time is 48-90h; the organic solvent is 1,4-dioxane, the heating reaction temperature is 90-100°C, and the heating reaction time is 48-90h.

[0020] According to a preferred embodiment of the present invention, the heating reaction described in step (1) is carried out under a nitrogen atmosphere.

[0021] According to a preferred embodiment of the present invention, the washing step in step (1) is as follows: the solid obtained after filtration is washed three times each with methanol, tetrahydrofuran, chloroform and acetone.

[0022] In this invention, the cage-like octavinylsilsesquioxane (OVS) and the organic fluorescent monomer (TSC) with a DA structure have the structures shown in formula (III) and formula (II), respectively:

[0023]

[0024] The cage-like octavinylsilsesquioxane (OVS) used in this invention can be prepared according to the literature J. Am. Chem. Soc., 1964, 86, 1120-1125; the organic fluorescent monomer (TSC) with DA structure can be prepared according to the patents WO2011019405A, 2011 and KR20110060318A, 2011; other raw materials are common commercial products.

[0025] According to a preferred embodiment of the present invention, the Soxhlet extraction step in step (2) is as follows: the solid A obtained in step (1) is subjected to Soxhlet extraction in tetrahydrofuran and methanol for 20-30 hours respectively.

[0026] According to a preferred embodiment of the present invention, the vacuum drying temperature in step (2) is 60-80°C and the vacuum drying time is 20-48h.

[0027] The aforementioned silsesquioxane fluorescent porous hybrid polymer with a DA structure is used for the adsorption and recovery of gold ions in solution under visible light.

[0028] According to the application of the present invention, the preferred application steps are as follows:

[0029] A silsesquioxane fluorescent porous hybrid polymer with a DA structure is added to a solution containing gold ions. Adsorption is performed under visible light irradiation, followed by filtration and calcination to recover the gold ions. The concentration of gold ions in the solution is 100–1600 ppm, and the pH is 1–6. The mass ratio of the silsesquioxane fluorescent porous hybrid polymer with the DA structure to the volume of the solution containing gold ions is 0.2–1 g:1 L. The adsorption time is 15–240 min. Calcination is performed using a blowtorch until the polymer carbonizes and the adsorbed gold on the surface melts into small spheres; the temperature and time are not specifically limited.

[0030] According to the present invention, the solution containing gold ions may also contain one or more other metal ions, such as Ni(II), Cu(II), Cd(III), Zn(II), Mg(II), Sr(II), and Pb(II).

[0031] According to the present invention, the gold obtained can be recovered by calcination after the polymer adsorption is saturated.

[0032] The reaction pathway for this reaction is shown below:

[0033]

[0034] The technical features and beneficial effects of this invention are as follows:

[0035] 1. The preparation steps of the fluorescent porous hybrid polymer of the present invention are simple and the process conditions are easy to control. The present invention uses octavinylsilsesquioxane with a specific cage structure and an organic fluorescent monomer with a DA structure as raw materials to prepare a silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure via the Heck reaction. In the present invention, the octavinyloctavinylsilsesquioxane monomer theoretically provides 8 reaction sites, and the numerous reaction sites are beneficial for forming a highly cross-linked porous structure.

[0036] 2. The introduction of cage-like silsesquioxanes into the fluorescent porous hybrid polymer of this invention improves the material's aging resistance, prevents π-π stacking between organic monomers, and enhances the material's fluorescence performance. The introduction of organic fluorescent monomers with DA structures gives the material good photogenerated carrier migration behavior and photocurrent response. The cage-like silsesquioxane polymer prepared by this invention has a large specific surface area and is rich in heteroatoms, which is beneficial for rapid adsorption and enhancing the interaction between the material and gold ions. In addition, this polymer has a wide light absorption range and a narrow optical band gap, with a valence band and conduction band of +1.38 eV and -0.35 eV, respectively, while the reduction potential of Au(III) is 1.002 eV, which is within the above range. Therefore, it can be used for photocatalytic reduction of gold ions. Thus, the polymer of this invention can rapidly adsorb gold ions and reduce them to elemental gold for gold ion recovery.

[0037] 3. The fluorescent porous hybrid polymer obtained in this invention exhibits excellent performance when applied to the adsorption and catalytic reduction of gold ions in solution under visible light. Experiments show that the adsorption efficiency can reach about 80% within 15 minutes, and the maximum adsorption capacity can reach about 3080 mg g after 4 hours of light irradiation. -1 For low-concentration gold ion solutions, it can reduce the concentration from ppm to ppb levels, and as an adsorbent, it exhibits excellent selectivity and anti-interference properties.

[0038] 4. The organic building block structure selected in this invention is novel, and the polymer designed based on it enriches the types of silsesquioxane hybrid materials, which has a certain degree of innovation. Attached Figure Description

[0039] Figure 1 This is the 1H NMR spectrum of the organic fluorescent monomer (TSC) with DA structure used in Example 1.

[0040] Figure 2 The organic fluorescent monomer (TPC) with a DA structure, using biphenyl as the electron-donating unit, was used in Comparative Example 1. 1 HNMR spectrum.

[0041] Figure 3The infrared spectra are those of the octavinylsilsesquioxane (OVS) used in Example 1, the organic fluorescent monomer (TSC) with a DA structure, and the prepared silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure.

[0042] Figure 4 The infrared spectra of the octavinylsilsesquioxane (OVS) used in Comparative Example 1, the organic fluorescent monomer (TPC) with a DA structure using biphenyl as the electron-donating unit, and the prepared polymer (PTPC) are shown.

[0043] Figure 5 These are solid-state carbon spectra of the octavinylsilsesquioxane (OVS) used in Example 1 and Comparative Example 1, the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1, and the polymer (PTPC) prepared in Comparative Example 1.

[0044] Figure 6 These are solid-state silicon spectra of the octavinylsilsesquioxane (OVS) used in Example 1 and Comparative Example 1, the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1, and the polymer (PTPC) prepared in Comparative Example 1.

[0045] Figure 7 These are X-ray diffraction spectra of the octavinylsilsesquioxane (OVS) used in Example 1 and Comparative Example 1, the silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure prepared in Example 1, and the polymer (PTPC) prepared in Comparative Example 1.

[0046] Figure 8 Thermogravimetric analysis curves of the octavinylsilsesquioxane (OVS) used in Example 1 and Comparative Example 1, the silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure prepared in Example 1, and the polymer (PTPC) prepared in Comparative Example 1 are shown.

[0047] Figure 9 The solid-state UV diffuse reflectance (a) and solid-state fluorescence curve (b) are the organic fluorescent monomer (TSC) with DA structure used in Example 1 and the prepared silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure.

[0048] Figure 10 The N2 adsorption-desorption curves (a) and pore size distribution diagrams (b) of the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1 are shown.

[0049] Figure 11The graph shows the relationship between the adsorption efficiency of Au(III) on time for the silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure prepared in Example 1 and the polymer (PTPC) prepared in Comparative Example 1 under dark and visible light irradiation.

[0050] Figure 12 The graph shows the relationship between the adsorption capacity of Au(III) on the silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure prepared in Example 1 and the polymer (PTPC) prepared in Comparative Example 1, under darkness and visible light irradiation, and the pH value.

[0051] Figure 13 The graph shows the relationship between the adsorption capacity of the silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure prepared in Example 1 and the polymer (PTPC) prepared in Comparative Example 1, and the changes in the concentration of Au(III) in the solution under dark and visible light irradiation.

[0052] Figure 14 This is an adsorption experiment diagram of Au(III) and other metal ions on the silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure prepared in Example 1 under visible light irradiation. The inset shows the initial concentration of different metal ions in the binary mixed system.

[0053] Figure 15 The image shows the XRD patterns of the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1 before and after Au(III) adsorption.

[0054] Figure 16 These are scanning electron microscope (SEM) images of the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1 after adsorption of Au(III) at different magnifications. Detailed implementation method:

[0055] The present invention will be further described below with reference to specific embodiments and accompanying drawings, but the scope of protection of the present invention is not limited thereto. Unless otherwise specified, the raw materials used in the embodiments can be obtained commercially or prepared according to existing technology; unless otherwise specified, the methods used are conventional methods, and unless otherwise specified, the equipment used is conventional equipment.

[0056] The octavinylsilsesquioxane (OVS) used in the examples can be prepared according to the literature J. Am. Chem. Soc., 1964, 86, 1120-1125. The preparation steps are as follows:

[0057] ① Add 300 mL of acetone, 60 mL of vinyltrimethoxysilane, and 60 mL of water to a 1000 mL single-necked flask. After stirring evenly, slowly add 80 mL of hydrochloric acid with a mass fraction of 36-38% at 0℃. After the addition is complete, stir for 3 min. After the system stabilizes, raise the temperature to room temperature and stir at room temperature for 5 days.

[0058] ② After the reaction is complete, filter the solid and wash it with acetone until no yellow substance is found. Dry it under vacuum to obtain a white powder solid.

[0059] The synthesis route is as follows:

[0060]

[0061] The organic fluorescent monomer (TSC) with a DA structure used can be prepared according to patents WO2011019405A,2011 and KR20110060318A,2011. The preparation steps are as follows:

[0062] ① Under a nitrogen atmosphere, dry N,N-dimethylformamide (DMF) (30 mL) and 2-thiophene acetonitrile (4.00 g, 32.47 mmol) were successively injected into a dry 100 mL three-necked flask. Then, N-bromosuccinimide (NBS) (6.07 g, 34.10 mmol) was slowly added (15 min), and the mixture was stirred overnight in the dark at room temperature. After the reaction was complete, the mixture was poured into deionized water (300 mL) and extracted with chloroform (3 × 50 mL). The extract was mixed and washed with deionized water, then dried overnight in anhydrous MgSO4. After filtration, the solvent was removed under vacuum, and the residue was purified by column chromatography (silica gel, petroleum:ethyl acetate = 15:1, v / v). The residue was then dried under vacuum at 80 °C for 24 h to give compound 1 as a pale yellow oil. The yield was 90.1%.

[0063] ② Compound 1 (4.00 g, 19.80 mmol), pinacol diborate (6.54 g, 8.58 mmol), [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride (Pd(dppf)2Cl2) (1.61 g, 1.98 mmol), and potassium acetate (6.78 g, 23.10 mmol) were dissolved in 1,4-dioxane (120 mL) in sequence. The reaction mixture was stirred at 100 °C for 3 h, cooled to room temperature, and then desolventized under vacuum to obtain the crude product. The crude product was then purified by column chromatography (silica gel, petroleum:ethyl acetate = 40:1, v / v). The product was dried under vacuum at 80 °C for 24 h to give compound 2 as a yellow solid, with a yield of 46.11%.

[0064] ③ Under a nitrogen atmosphere, compound 1 (1.62 g, 8.00 mmol), compound 2 (2.43 g, 8.6 mmol), and tetrakis(triphenylphosphine)palladium (Pd[P(C6H5)3]4) (1.11 g, 0.96 mmol) were dissolved in tetrahydrofuran (THF) (50 mL). Then, 2 mol / L K2CO3 solution (8 mL) was added, and the mixture was stirred at room temperature for 30 min, then heated to 85 °C and stirred for 24 h. After cooling to room temperature, the reaction mixture was poured into 300 mL of deionized water and extracted with dichloromethane (3 × 50 mL). The extracts were mixed and washed with deionized water, then dried over anhydrous MgSO4. After filtration, the solvent was removed under vacuum, and the residue was purified by column chromatography (silica gel, petroleum:ethyl acetate = 8:1, v / v). The residue was then dried under vacuum at 80 °C for 24 h to obtain compound 3 as an orange solid, with a yield of 49.74%.

[0065] ④ Under a nitrogen atmosphere, in a 25 mL three-necked flask, compound 3 (781 mg, 3.20 mmol) was dissolved in a mixed solution of chloroform and ethanol (V). CHCl3 :V EtOH In a solution of sodium ethoxide (EtONa) (440 mg, 6.47 mmol) and p-bromobenzaldehyde solution (2.00 g), the mixture was stirred at room temperature for 30 min, then heated to 60 °C and stirred for 5 h. After cooling to room temperature, the solvent was removed under vacuum to obtain the crude product, which was then purified by column chromatography (silica gel, petroleum:ethyl acetate = 50:1, v / v). The product was dried under vacuum at 80 °C for 24 h to obtain an organic fluorescent monomer (TSC) with a DA structure, which was an orange solid with a yield of 73.53%. 1 H NMR spectrum as follows Figure 1 As shown.

[0066] The synthesis route is as follows:

[0067]

[0068] The organic fluorescent monomer (TPC) with a DA structure and biphenyl as the electron-donating unit used in the comparative example can be prepared according to patent J. Mater. Chem. C 2017, 5(19), 4763-4774. The preparation steps are as follows:

[0069] Under a nitrogen atmosphere, 4,4'-biphenylacetonitrile (781 mg, 3.20 mmol) was dissolved in a mixture of chloroform and ethanol in a 100 mL three-necked flask (V). CHCl3 :V EtOHIn a 1:1, 100 mL solution, sodium ethoxide (EtONa) (440 mg, 6.47 mmol) and p-bromobenzaldehyde (2.00 g) were added. The mixture was allowed to stand at room temperature for one day, and the crude product was filtered off. This crude product was then purified by column chromatography (silica gel, petroleum ether:ethyl acetate = 4:1, v / v). The product was dried under vacuum at 80 °C for 24 h to obtain a bright yellow solid (TPC) with a DA structure and biphenyl as the electron-donating unit, yielding 63.25%. 1 H NMR spectrum as follows Figure 2 As shown.

[0070] The synthesis route is as follows:

[0071]

[0072] Example 1

[0073] A method for preparing a silsesquioxane fluorescent porous hybrid polymer with a DA structure includes the following steps:

[0074] (1) Under a nitrogen atmosphere, in a dry 100 mL three-necked flask, an organic fluorescent monomer with a DA structure (TSC) (1.04 g, 1.80 mmol), a cage-like octavinylsilsesquioxane (OVS) (456 mg, 0.72 mmol), palladium acetate (31.7 mg, 0.14 mmol), tris(o-methylphenyl)phosphine (92.64 mg, 0.30 mmol), sodium bicarbonate (758 mg, 9.10 mmol), and anhydrous DMF (50 mL) were added, respectively. After being fully dispersed and mixed, the mixture was heated to 120 °C and stirred for 72 h. After the reaction was completed, it was naturally cooled to room temperature, filtered, and the obtained solid was washed three times each with methanol, tetrahydrofuran, chloroform, and acetone to remove unconsumed monomers, catalyst residues, and sodium salts, to obtain solid A.

[0075] (2) In a Soxhlet apparatus, the solid A obtained in step (1) was extracted with tetrahydrofuran and methanol for 24 h, respectively. Then the solid was vacuum dried at 80 °C for 24 h to obtain a sesquioxane fluorescent porous hybrid polymer with DA structure, a brown powder, denoted as PTSC, with a yield of 70%.

[0076] Comparative Example 1

[0077] The polymer was synthesized using an organofluorescent monomer (TPC) with a DA structure that uses biphenyl as the electron-donating unit. The preparation method was the same as in Example 1, except that the amount of organofluorescent monomer (TPC) with a DA structure was changed to 1.02 g, while the amounts of other raw materials and reagents remained unchanged. The final comparative polymer was a dark green powder, denoted as PTPC, with a yield of 97%.

[0078] The comprehensive analysis is as follows:

[0079] The infrared spectra of the octavinylsilsesquioxane (OVS), the organic fluorescent monomer (TSC) with a DA structure, and the prepared silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure used in Example 1 are shown below. Figure 3 As shown, by Figure 3 It can be seen that, compared with the two monomers (OVS, TSC), the polymer PTSC exhibits the presence of two molecules located at 2200 cm⁻¹ in its infrared spectrum. -1 and 1118cm -1 The characteristic peaks of the nitrile group and Si-O-Si at the position indicate that the two monomers have been successfully cross-linked.

[0080] The infrared spectra of the octavinylsilsesquioxane (OVS) used in Comparative Example 1, the organofluorescent monomer (TPC) with a DA structure using biphenyl as the electron-donating unit, and the prepared polymer (PTPC) are shown below. Figure 4 As shown, by Figure 4 As can be seen, compared with the two monomers (OVS, TPC), the polymer PTPC also has an infrared spectrum at 2216 cm⁻¹. -1 and 1078cm -1 The characteristic peaks of the nitrile group and Si-O-Si at the position indicate that the two monomers have been successfully cross-linked.

[0081] The solid-state carbon spectra of the octavinylsilsesquioxane (OVS) used in Example 1 and Comparative Example 1, the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1, and the polymer (PTPC) prepared in Comparative Example 1 are shown below. Figure 5 As shown, the broad peaks of polymers PTSC and PTPC around 140–130 ppm can be attributed to carbon atoms in the benzene and thiophene rings in the polymers, as well as carbon atoms in the unreacted vinyl groups in OVS. The peak around 105 ppm can be attributed to carbon atoms in the nitrile groups.

[0082] The solid-state silicon spectra of the octavinylsilsesquioxane (OVS) used in Example 1 and Comparative Example 1, the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1, and the polymer (PTPC) prepared in Comparative Example 1 are shown below. Figure 6 As shown, the peaks of polymers PTSC and PTPC at -80.1 ppm belong to the T3 unit (T... n =CSi(OSi) n (OH) 3-nThe small peak of PTST at -109.4 ppm can be attributed to silicon atoms in the Q3(Si(OSi)3OH) and Q4(Si(OSi)4) units generated by the collapse of the cage structure, respectively.

[0083] The X-ray diffraction spectra of the octavinylsilsesquioxane (OVS) used in Example 1 and Comparative Example 1, the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1, and the polymer (PTPC) prepared in Comparative Example 1 are shown below. Figure 7 As shown, by Figure 7 It can be seen that both polymers PTSC and PTPC have amorphous structures.

[0084] Thermogravimetric analysis curves of the octavinylsilsesquioxane (OVS) used in Example 1 and Comparative Example 1, the silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure prepared in Example 1, and the polymer (PTPC) prepared in Comparative Example 1 are shown below. Figure 8 As shown, Figure 8 This indicates that both polymers PTSC and PTPC have good thermal stability, with PTSC exhibiting a 5% thermal weight loss at approximately 250°C.

[0085] The solid-state UV diffuse reflectance and solid-state fluorescence curves of the organic fluorescent monomer (TSC) with DA structure used in Example 1 and the prepared silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure are shown below. Figure 9 As shown, the UV and fluorescence images demonstrate that the polymer PTSC has good optical properties.

[0086] The N2 adsorption-desorption curves and pore size distribution diagrams of the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1 are shown below. Figure 10 As shown in the figure, the test results indicate that the specific surface area of ​​polymer PTSC is 455 m². 2 g -1 Furthermore, micropores and mesopores coexist, with micropores mainly concentrated between 1.54 and 1.76 nm, while mesopores are mainly concentrated between 2.42 and 12 nm.

[0087] Experimental Example 1

[0088] The adsorption efficiency of polymer PTSC obtained in Example 1 and polymer PTPC obtained in Comparative Example 1 for Au(III) was investigated under dark and light conditions, respectively, in relation to time.

[0089] To investigate the relationship between adsorption time and adsorption efficiency, the adsorption efficiencies of PTSC and PTPC for Au(III) at different time points were tested. 2 mg of PTSC or PTPC was dispersed in 10 mL of a 250 ppm, pH 4 acidic aqueous solution containing gold ions (the gold ion solution was prepared by dissolving chloroauric acid in deionized water and adjusting the pH to 4 with 37 wt% hydrochloric acid). Two test samples were prepared, one irradiated with visible light and the other as a dark control. After adsorption at different times (15 min, 20 min, 25 min, 30 min, 60 min, 120 min, 240 min, 360 min), 500 μL of each suspension was filtered. The filtrate was diluted with deionized water, and the concentration of Au(III) in the filtrate was determined by atomic flame absorption spectroscopy. The adsorption efficiencies of PTSC and PTPC at different time points were calculated using the following formula:

[0090]

[0091]

[0092] In the formula: Q t The adsorption amounts of Au(III) by PTSC and PTPC at different time points are in mg / g.

[0093] Q m The maximum adsorption capacity of PTSC and PTPC for Au(III) in this adsorption experiment is mg / g;

[0094] m represents the mass of PTSC and PTPC added, in grams.

[0095] C0 is the initial concentration of Au(III), mg / L;

[0096] C t The concentration of Au(III) in the filtrate obtained at different times is mg / L;

[0097] V is the volume of the Au(III) aqueous solution during the adsorption experiment, in L.

[0098] Figure 11This is a graph showing the adsorption efficiency of polymer PTSC obtained in Example 1 and polymer PTPC obtained in Comparative Example 1 for Au(III) under darkness and visible light irradiation, respectively, as a function of time. The graph shows that light irradiation significantly enhances the adsorption efficiency of both polymers PTSC and PTPC for Au(III). Under light irradiation, polymer PTSC achieves an adsorption efficiency of approximately 80% within 15 minutes and reaches adsorption equilibrium within approximately 30 minutes. In contrast, polymer PTPC's adsorption efficiency is only about 35% within 15 minutes, then increases slowly, reaching equilibrium after approximately 120 minutes. Furthermore, under darkness, PTSC achieves an adsorption efficiency of approximately 60% within 6 hours, while PTPC shows virtually no adsorption. Therefore, the adsorption efficiency of PTSC for Au(III) is far superior to that of PTPC.

[0099] Experimental Example 2

[0100] The relationship between pH and the adsorption capacity of Au(III) by PTSC obtained in Example 1 and PTPC obtained in Comparative Example 1 under dark and light conditions was investigated.

[0101] To investigate the effect of pH on the adsorption performance of PTSC and PTPC, the adsorption capacity of PTSC or PTPC for Au(III) at different pH values ​​was tested. 2 mg of PTSC or PTPC was dispersed in 10 mL of gold ion solutions with a concentration of 900 ppm and pH values ​​ranging from 1 to 6 (the gold ion solution was prepared by dissolving chloroauric acid in deionized water and adjusting the pH with 37 wt% hydrochloric acid). Two sets of test samples were prepared: one group was irradiated with visible light, and the other served as a dark control. Each test sample was stirred for 240 min, then the adsorbent was filtered off, diluted with water, and the concentration of Au(III) in the filtrate was determined by atomic flame absorption spectroscopy. The adsorption capacity of PTSC and PTPC for Au(III) at different pH values ​​was calculated using the following formula:

[0102]

[0103] In the formula: Q e The adsorption capacity of PTSC and PTPC for Au(III) at the equilibrium time is mg / g.

[0104] m represents the mass of PTSC and PTPC added, in grams.

[0105] C0 is the initial concentration of Au(III), mg / L;

[0106] C e The concentration of Au(III) in the filtrate obtained at the equilibrium time is in mg / L;

[0107] V is the volume of the Au(III) aqueous solution during the adsorption experiment, in L.

[0108] Figure 12 This is a graph showing the relationship between the adsorption capacity of polymer PTSC obtained in Example 1 and polymer PTPC obtained in Comparative Example 1 for Au(III) and pH under dark and visible light irradiation. As shown in the graph, for PTSC, regardless of whether under light or dark conditions, the adsorption capacity of PTSC for Au(III) generally increases with increasing pH. The adsorption effect of PTSC is most excellent at pH=5, which is the preferred condition. PTPC, on the other hand, shows almost no adsorption under dark conditions, but under light conditions, the adsorption effect is most excellent at pH=4, which is also the preferred condition.

[0109] Experimental Example 3

[0110] The graphs show the relationship between the adsorption performance of PTSC obtained in Example 1 and PTPC obtained in Comparative Example 1 for Au(III) and the concentration of Au(III) in the solution under dark and light conditions, respectively.

[0111] To investigate the effect of Au(III) concentration on the adsorption performance of PTSC, 2 mg of PTSC was dispersed in 10 mL of gold ion solutions of different concentrations (130 ppm, 250 ppm, 360 ppm, 580 ppm, 780 ppm, 1080 ppm, 1380 ppm, 1580 ppm) at pH 5 (the gold ion solutions were prepared by dissolving chloroauric acid in deionized water and adjusting the pH to 5 with 37 wt% hydrochloric acid). Two sets of test samples were prepared, one group irradiated with visible light and the other group as a dark control. Each test sample was stirred for 240 min, then the adsorbent was filtered off, diluted, and the concentration of Au(III) in the filtrate was determined by atomic flame absorption spectroscopy. The adsorption capacity of PTSC in Au(III) aqueous solutions of different concentrations was calculated using the formula in Experimental Example 2. To investigate the effect of Au(III) concentration on the adsorption performance of PTPC, 2 mg of PTPC was dispersed in 10 mL of gold ion solutions of different concentrations (140 ppm, 270 ppm, 370 ppm, 570 ppm, 800 ppm, 900 ppm, 1180 ppm) at pH=4. The remaining operations were the same as those described above.

[0112] Figure 13 This is a graph showing the relationship between the adsorption performance of polymer PTSC obtained in Example 1 and polymer PTPC obtained in the comparative example for Au(III) and the concentration of Au(III) in the solution under dark and visible light irradiation. As can be seen from the graph, the adsorption performance of both polymers for Au(III) increases significantly under light irradiation, and the adsorption effect of PTSC is better than that of PTPC, with a maximum adsorption capacity reaching approximately 3080 mg / g. -1The maximum adsorption capacity of PTPC is approximately 2746 mg g. -1 Furthermore, at high concentrations (>900 ppm), the adsorption capacity of PTPC for Au(III) decreased significantly, showing a clear difference compared to the adsorption effect of PTSC. This can be attributed to the presence of S atoms in PTSC, which leads to greater interaction between the polymer and gold ions.

[0113] Test Example 4

[0114] The selectivity and anti-interference properties of PTSC obtained in Example 1 as an Au(III) adsorbent were investigated.

[0115] To investigate the selectivity and anti-interference properties of PTSC, metal ion solutions with a concentration of 100 ppm and pH = 5 were first prepared (the gold ion solution was prepared by dissolving chloroauric acid in deionized water and adjusting the pH to 5 with 37 wt% hydrochloric acid). Ni(II), Cu(II), Cd(II), Zn(II), Mg(II), Sr(II), and Pb(II) ions were added to the gold ion solutions (the metal salts of each ion are as follows: NiCl2, Cu(NO3)2·3H2O, Cd(NO3)2, ZnCl2, MgSO4, SrCl2, Pb(NO3)2). Considering that the concentration of other metal ions in actual electronic wastewater is much higher than that of gold ions, Au(III) was mixed with any one of the above metal ions, and the concentrations of each metal ion were as follows. Figure 14 As shown in the illustration, a binary mixed system was prepared. 2 mg of PTSC was dispersed in 10 mL of each of the above-mentioned binary mixed solutions. Each test sample was stirred under visible light irradiation for 240 min, after which the adsorbent was filtered off, diluted with water, and the concentration of metal ions in the filtrate was determined by atomic flame absorption spectroscopy. The adsorption capacity of PTSC for different metal ions was calculated using the formula in Example 2.

[0116] Figure 14 The results of the selectivity and anti-interference tests of PTSC are shown, with the inset showing the actual concentrations of different metal ions in the binary mixed system. As can be seen from the figure, as an Au(III) adsorbent, PTSC can reduce the concentration of Au(III) in solution from ppm to ppb levels in the presence of different metal ions, with adsorption efficiencies generally above 99%, demonstrating excellent selectivity and anti-interference properties.

[0117] Figure 15 The XRD curves of the silsesquioxane fluorescent porous hybrid polymer (PTSC) with DA structure prepared in Example 1 before and after Au(III) adsorption are shown. The curves show obvious nano-gold signals, indicating that PTSC can reduce the adsorbed Au(III) to elemental gold.

[0118] Figure 16 The images are scanning electron microscope (SEM) images of the silsesquioxane fluorescent porous hybrid polymer (PTSC) with a DA structure prepared in Example 1 after adsorption of Au(III) at different magnifications, showing obvious gold nanoparticles.

[0119] The above-described test examples are merely preferred test examples of the present invention and are not intended to limit the present invention.

Claims

1. A silsesquioxane fluorescent porous hybrid polymer having a DA structure, characterized in that, The fluorescent porous hybrid polymer has the structural unit shown in formula (I); the fluorescent polymer is constructed by connecting an octavinylsilsesquioxane building unit with a cage structure and an organic fluorescent monomer with a DA structure via a bridging bond -Si-CH=CH-phenyl; the organic fluorescent monomer with a DA structure has the structure shown in formula (II). 。 2. The method for preparing the silsesquioxane fluorescent porous hybrid polymer with a DA structure according to claim 1, comprising the following steps: (1) Dissolve octavinylsilsesquioxane with a cage-like structure and an organic fluorescent monomer with a DA structure in an organic solvent, add a catalyst and a base, mix well, and then heat to react; after the reaction is completed, cool, filter, and wash to obtain solid A; (2) The solid A obtained in step (1) is subjected to Soxhlet extraction, and the solid obtained is dried under vacuum to obtain a sesquioxane fluorescent porous hybrid polymer with a DA structure.

3. The method for preparing the silsesquioxane fluorescent porous hybrid polymer with a DA structure according to claim 2, characterized in that, The molar ratio of the organic fluorescent monomer with DA structure to the octavinylsilsesquioxane with cage structure mentioned in step (1) is (1~4):

1.

4. The method for preparing the silsesquioxane fluorescent porous hybrid polymer with a DA structure according to claim 2, characterized in that, The molar ratio of the organic fluorescent monomer with DA structure to the octavinylsilsesquioxane with cage structure mentioned in step (1) is (2~3):

1.

5. The method for preparing the silsesquioxane fluorescent porous hybrid polymer with a DA structure according to claim 2, characterized in that, The organic solvent mentioned in step (1) is N,N-dimethylformamide or 1,4-dioxane; the mass ratio of the cage-like octavinylsilsesquioxane to the volume ratio of the organic solvent is 1 g:(50~150) mL.

6. The method for preparing the silsesquioxane fluorescent porous hybrid polymer with a DA structure according to claim 2, characterized in that, The catalyst mentioned in step (1) is tetra(triphenylphosphine)palladium or palladium acetate-ligand tri(o-methylphenyl)phosphine; the molar ratio of the catalyst to the cage-shaped octavinylsilsesquioxane is (0.14~0.48):1; the molar ratio of palladium acetate to tri(o-methylphenyl)phosphine ligand in palladium acetate-ligand tri(o-methylphenyl)phosphine is 1: (1.8~2.2).

7. The method for preparing the silsesquioxane fluorescent porous hybrid polymer with a DA structure according to claim 2, characterized in that, The alkali mentioned in step (1) is one or more of sodium bicarbonate, potassium carbonate, and triethylamine; the mass ratio of the alkali to the cage-like octavinylsilsesquioxane is (1~3):

1.

8. The method for preparing the silsesquioxane fluorescent porous hybrid polymer with a DA structure according to claim 2, characterized in that, In step (1), when the organic solvent is N,N-dimethylformamide, the heating reaction temperature is 110~140℃ and the heating reaction time is 48~90h; when the organic solvent is 1,4-dioxane, the heating reaction temperature is 90~100℃ and the heating reaction time is 48~90h; the heating reaction is carried out under a nitrogen atmosphere. The washing steps are as follows: the solid obtained after filtration is washed three times each with methanol, tetrahydrofuran, chloroform and acetone.

9. The method for preparing the silsesquioxane fluorescent porous hybrid polymer with a DA structure according to claim 2, characterized in that, The Soxhlet extraction step in step (2) is as follows: the solid A obtained in step (1) is extracted by Soxhlet extraction in tetrahydrofuran and methanol for 20-30 h respectively; the vacuum drying temperature is 60-80℃ and the vacuum drying time is 20-48 h.

10. The application of the silsesquioxane fluorescent porous hybrid polymer having a DA structure as described in claim 1, characterized in that, Used for adsorption and recovery of gold ions in solution under visible light.

11. The application according to claim 10, characterized in that, The specific application steps are as follows: A silsesquioxane fluorescent porous hybrid polymer with a DA structure was added to a solution containing gold ions, and adsorption was carried out under visible light irradiation. After filtration, the polymer was calcined to complete the adsorption and recovery of gold ions. The concentration of gold ions in the solution containing gold ions is 100~1600ppm, and the pH of the solution containing gold ions is 1~6; the mass ratio of the silsesquioxane fluorescent porous hybrid polymer with DA structure to the volume of the solution containing gold ions is 0.2~1g:1L; and the adsorption time is 15~240min.

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