Preparation method and application of S-rich thiophene-based covalent organic polymer material
The S-rich thiophene-based covalent organic polymer material was synthesized by a solvothermal method, which solved the problems of small mercury ion adsorption capacity and slow kinetics of traditional adsorbents in aqueous solution, and achieved efficient mercury ion adsorption effect and stable material properties.
Patent Information
- Application Number
- CN202411490917.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-24
- Publication Date
- 2025-09-23
- Estimated Expiration
- 2044-10-24
AI Technical Summary
Existing adsorbents have a small adsorption capacity for mercury ions in aqueous solutions and slow adsorption kinetics. The synthesis conditions of traditional materials are harsh and have low repeatability, making it difficult to effectively remove mercury ions from water.
S-rich thiophene-based covalent organic polymer materials were synthesized by a solvothermal method, and novel covalent organic polymers connected by imine bonds were prepared by amine-aldehyde condensation reaction for the adsorption of heavy metal mercury ions in aqueous solution.
Efficient mercury ion adsorption was achieved in the pH range of 3-7, with a maximum adsorption capacity of 170.6 mg·g-1. The material has good stability, mild synthesis conditions, and is easy to apply in industry.
Smart Images
Figure CN119219876B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of organic functional materials and heavy metal adsorption, and in particular to a method for preparing a S-rich thiophene-based covalent organic polymer material and its application in adsorbing heavy metal mercury ions in aqueous solution. Background Art
[0002] Mercury is one of the most common and dangerous heavy metal elements. Due to its high toxicity, accumulation, and persistence, it causes significant harm to human health and ecosystems. Mercury is widely used in the fields of chemistry, medicine, transportation, and metallurgy. In particular, wastewater discharged from industries such as electroplating and batteries inevitably contains large amounts of divalent mercury ions. Mercury exists in multiple forms and transforms between these forms through various reactions such as redox and methylation. Mercury ions, as the most common form in aqueous media, can be converted into highly toxic methylmercury in complex aqueous environments, causing irreversible damage to the human body, leading to lifelong and even life-threatening consequences. Therefore, removing mercury from the environment is of great practical significance, and we urgently need to find excellent materials with fast kinetics and high adsorption capacity to effectively remediate and capture mercury ions from wastewater.
[0003] Currently, a wide range of methods are used to treat mercury in wastewater, including adsorption, solution extraction, ion exchange, chemical precipitation, microbial treatment, and membrane separation. Among the numerous mercury removal methods, adsorption has attracted widespread attention due to its simplicity, low cost, and ease of regeneration, and has long been considered one of the most effective methods for heavy metal removal. To date, a variety of adsorbents have been prepared for mercury removal, including porous activated carbon, zeolites, clays, nanocomposites, metal-organic frameworks, and covalent organic polymers. Traditional adsorbents are limited in their active functional groups for mercury ion recognition and binding, resulting in low adsorption capacity and slow adsorption kinetics. For example, zeolites and porous activated carbon are both the most commonly used mercury adsorbents. However, the adsorption performance of these traditional adsorbents remains far from ideal, particularly for mercury capture in aqueous solutions.
[0004] In comparison, covalent organic polymers (COPs), formed by strong covalent bonds linking lightweight elements such as C, H, O, and N, offer excellent chemical and thermal stability. Their high reproducibility, structural tunability, and ease of functionalization make them ideal materials for mercury removal from wastewater. However, current COPs materials have a relatively low adsorption capacity for mercury ions in aqueous solutions. Furthermore, the preparation processes for most materials are demanding, with low reproducibility and difficulty in synthesis. Summary of the Invention
[0005] The present invention aims to provide a method for preparing and applying a sulfur-rich thienyl covalent organic polymer material to address the aforementioned problems in the prior art. The present invention synthesizes a novel sulfur-rich thienyl covalent organic polymer material connected by imine bonds via a simple solvothermal method and an amine-aldehyde condensation reaction. The material can effectively adsorb and remove heavy metal mercury ions from aqueous solutions. The sulfur-rich thienyl covalent organic polymer material can remove mercury ions within a pH range of 3-7, with a maximum adsorption capacity of 170.6 mg·g. -1 .
[0006] To achieve the above object, the present invention provides the following solutions:
[0007] One of the technical solutions of the present invention is a S-rich thiophene-based covalent organic polymer material, the structural formula of which is as follows:
[0008]
[0009] The second technical solution of the present invention: A method for preparing the above-mentioned S-rich thiophene-based covalent organic polymer material comprises the following steps: mixing benzo[1,2-b:3,4-b':5,6-b"]terthiophene-2,5,8-tricarbaldehyde (BTT for short) and pyrazine-2,5-diazide (PQH for short) with a solvent, and then adding acetic acid to obtain a mixed solution; subjecting the mixed solution to a freeze-thaw cycle deoxygenation treatment, and then sealing and heating the solution for reaction to obtain the S-rich thiophene-based covalent organic polymer material (BTT-PQH for short).
[0010] Furthermore, the solvent is 1,3,5-trimethylbenzene (Mesitylene) and 1,4-dioxane (1,4-Dioxane).
[0011] Furthermore, the concentration of the acetic acid (HAc) is 6M.
[0012] Furthermore, the usage ratio of the benzo[1,2-b:3,4-b':5,6-b"]terthiophene-2,5,8-tricarbaldehyde, pyrazine-2,5-diazide, 1,3,5-trimethylbenzene, 1,4-dioxane and acetic acid is 0.2 mmol:0.3 mmol:4 mL:4 mL:0.8 mL.
[0013] Furthermore, the heating reaction temperature is 120° C. and the time is 3 days (72 hours).
[0014] Furthermore, after mixing benzo[1,2-b:3,4-b':5,6-b"]terthiophene-2,5,8-tricarbaldehyde and pyrazine-2,5-diazidine with a solvent, the process further includes ultrasonic treatment for 20 minutes, and then adding acetic acid after ultrasonic treatment for 20 minutes; and continuing ultrasonic treatment for 10 minutes after adding acetic acid.
[0015] Furthermore, the freeze-thaw cycle deoxygenation treatment of the mixed solution specifically includes: rapid freezing in liquid nitrogen and performing three freeze-thaw cycles.
[0016] The synthesis route of the above-mentioned S-rich thiophene-based covalent organic polymer material is as follows:
[0017]
[0018] The third technical solution of the present invention: Application of the above-mentioned S-rich thienyl covalent organic polymer material in the adsorption of heavy metal mercury ions in aqueous solution.
[0019] Furthermore, the adsorption conditions include: the pH value of the aqueous solution is 3-7.
[0020] Furthermore, the adsorption conditions also include: room temperature; mercury ion concentration in the aqueous solution is 50 mg·L -1 The S-rich thienyl covalent organic polymer material is added to the aqueous solution at a concentration of 0.2 mg·L -1 .
[0021] The present invention successfully prepares a S-rich thienyl covalent organic polymer through a simple solvothermal method by condensing the monomers benzo[1,2-b:3,4-b':5,6-b"]terthiophene-2,5,8-tricarbaldehyde and the monomer pyrazine-2,5-diazidine amine aldehyde. The polymer can serve as an effective adsorbent for mercury ions. The rich S / N ratio in the S-rich thienyl covalent organic polymer ensures sufficient affinity for mercury, thereby achieving efficient adsorption of mercury. The present invention provides a feasible method for the design and preparation of mercury adsorbents.
[0022] The present invention discloses the following technical effects:
[0023] (1) The sulfur-rich thiophene-based covalent organic polymer material BTT-PQH synthesized in the present invention has a good effect on the adsorption and removal of mercury ions in aqueous solution. It can effectively remove mercury in a wide range of pH 3-7, with a maximum adsorption capacity of 170.6 mg g -1 .
[0024] (2) The synthesis method of the present invention requires simple equipment, the chemical reagents used are easily available, the synthesis conditions are mild, the product structure is stable and not easily hydrolyzed (the infrared spectrum of BTT-PQH after immersion in aqueous solution for 48 hours is basically unchanged), the industrial application value is high, the practical application is effective, and it is easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0026] Figure 1 The Fourier transform infrared spectra of the monomer benzo[1,2-b:3,4-b':5,6-b"]terthiophene-2,5,8-tricarbaldehyde and the monomer pyrazine-2,5-diazidine and the covalent organic polymer material BTT-PQH of Example 1 are shown;
[0027] Figure 2 Scanning electron microscopy (SEM) images of the covalent organic polymer material BTT-PQH prepared in Example 1, wherein (a) and (b) represent SEM images at different positions, respectively;
[0028] Figure 3 The infrared spectra of the covalent organic polymer material BTT-PQH prepared in Example 1 before and after being immersed in an aqueous solution for 48 hours;
[0029] Figure 4 is the adsorption capacity of the covalent organic polymer material BTT-PQH for mercury ions at pH 1-7;
[0030] Figure 5 It is the specific adsorption effect of the covalent organic polymer material BTT-PQH on mercury ions in the presence of multiple coexisting ions. DETAILED DESCRIPTION
[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0032] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.
[0033] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.
[0034] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.
[0035] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.
[0036] The raw materials used in the specific embodiment of the present invention are all common commercial products, among which the structural formula of BTT is The CAS number is 2243590-42-1; the structural formula of pyrazine-2,5-dihydrazide is The CAS number is 46321-76-0.
[0037] The room temperature involved in the specific implementation manner of the present invention specifically refers to 20-30°C.
[0038] Example 1
[0039] A method for preparing a S-rich thiophene-based covalent organic polymer material comprises the following steps:
[0040] Monomer BTT (66.1 mg, 0.2 mmol) and pyrazine-2,5-dihydrazide (58.8 mg, 0.3 mmol) were added to a 25 mL Schlenk tube. 1,3,5-Trimethylbenzene (4 mL) and 1,4-dioxane (4 mL) were then added. The mixture was sonicated for 20 minutes to achieve a homogeneous mixture. 0.8 mL of 6 M acetic acid was then added and sonicated for another 10 minutes to obtain a mixed solution. The Schlenk tube was then flash-frozen in liquid nitrogen, deoxygenated through three freeze-thaw cycles, sealed, and allowed to react undisturbed at 120°C for 3 days (72 hours). After the reaction, the mixture was cooled to room temperature, collected by filtration, and washed with methanol, tetrahydrofuran, water, and ethanol. The washed material was dried in a vacuum oven at 60°C for 12 hours to obtain a S-rich thienyl covalent organic polymer (BTT-PQH) in a yield of 71% (89 mg).
[0041] Test Example 1
[0042] Morphological and structural characterization of covalent organic polymer materials
[0043] Figure 1 The Fourier transform infrared spectra of the monomer benzo[1,2-b:3,4-b':5,6-b"]terthiophene-2,5,8-tricarbaldehyde and the monomer pyrazine-2,5-diazidine and the covalent organic polymer material BTT-PQH of Example 1 are shown. Figure 1 In the infrared spectrum of BTT-PQH, CHO (1656 cm -1 ) and the obvious weakening of the characteristic peak of -NH2 (3000–3300cm -1 ) characteristic peak disappears. In addition, the peak at 1599 cm -1 An obvious new peak appears at , which is attributed to the vibration stretching band of the imine bond (C=N), indicating the successful formation of the polymer.
[0044] Figure 2 This is a scanning electron microscope image of the covalent organic polymer material BTT-PQH prepared in Example 1, where (a) and (b) represent SEM images at different positions. Figure 2 It can be seen that the morphology of BTT-PQH is formed by the stacking of many small nanoparticles.
[0045] Figure 3 The infrared spectra of the covalent organic polymer material BTT-PQH prepared in Example 1 before and after being immersed in aqueous solution for 48 hours are shown in FIG. Figure 3 It can be seen that the infrared spectrum of BTT-PQH after being immersed in aqueous solution for 48 hours has basically no change, proving that its structure is stable and not easily hydrolyzed.
[0046] Test Example 2
[0047] Test of the adsorption performance of covalent organic polymer materials for mercury ions
[0048] Test method:
[0049] 1. Effect of pH: At room temperature, in 50mL of initial mercury ions (Hg 2+ ) concentration is 50 mg·L -1 10 mg of BTT-PQH adsorbent (prepared in Example 1) was added to the mercury solution for adsorption. After reaching adsorption equilibrium, the solution was filtered with a 0.22 μm filter head, and 2 mL of the clear solution was diluted and analyzed by ICP-MS for Hg in the filtered solution. 2+ The adsorption capacity of BTT-PQH for mercury ions in different pH environments was calculated based on the residual content.
[0050] 2. Competitive adsorption experiment: The initial concentration of each metal ion was 100 mg·L by directly dissolving hydrochloride or nitrate in water. -1 Mixed metal ion solution (Hg 2+ Mg 2+ 、Al 3+ 、Mn 2+ 、Co 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ 、Sr 2+ 、Cd 2+ 、Cs 2+ 、La 3+ 、Eu 3+ 、Gd 3+ 、Dy 4+ , Pb 2+ The concentration was 100 mg·L -1 ), and then diluted to a concentration of 10 mg·L for each metal ion before use. -1 , and the pH was adjusted to 6. 10 mg of BTT-PQH adsorbent (prepared in Example 1) was added to the mixed metal ion solution at pH 6 for adsorption. After reaching adsorption equilibrium, the solution was filtered through a 0.22 μm filter, and 2 mL of the supernatant was diluted and analyzed using ICP-MS to analyze the remaining content of each metal ion in the filtered solution. The removal rate of each metal ion by BTT-PQH was calculated.
[0051] Test results: Figure 4 is the adsorption capacity of BTT-PQH for mercury ions at pH 1-7, Figure 4 It can be seen that BTT-PQH can effectively remove mercury in a wide range of pH 3-7, with a maximum adsorption capacity of 170.6 mg g-1 . Figure 5 The adsorption effect of BTT-PQH on mercury ions in the presence of multiple coexisting interfering ions. Figure 5 It can be seen that BTT-PQH can 2+ Specific adsorption was performed and in the presence of 15 coexisting interfering ions, the mercury removal rate of BTT-PQH was 78.5%, showing excellent anti-interference ability.
[0052] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.
Claims
1. A S-rich thiophene-based covalent organic polymer material, characterized in that: The structural formula is as follows:
2. The method for preparing the S-rich thienyl covalent organic polymer material according to claim 1, wherein: The following steps are involved: Benzo[1,2-b:3,4-b':5,6-b"]terthiophene-2,5,8-tricarbaldehyde and pyrazine-2,5-diazidine are mixed with a solvent, and then acetic acid is added to obtain a mixed solution; the mixed solution is subjected to a freeze-thaw cycle deoxygenation treatment, and then sealed and heated for reaction to obtain the S-rich thienyl covalent organic polymer material.
3. The preparation method according to claim 2, wherein The solvents are 1,3,5-trimethylbenzene and 1,4-dioxane.
4. The preparation method according to claim 2, wherein The concentration of the acetic acid was 6M.
5. The preparation method according to claim 3, wherein The usage ratio of the benzo[1,2-b:3,4-b':5,6-b"]terthiophene-2,5,8-tricarbaldehyde, pyrazine-2,5-diazide, 1,3,5-trimethylbenzene, 1,4-dioxane and acetic acid is 0.2 mmol:0.3 mmol:4 mL:4 mL:0.8 mL.
6. The preparation method according to claim 2, wherein The heating reaction was carried out at a temperature of 120° C. for 3 days.
7. Use of the S-rich thienyl covalent organic polymer material according to claim 1 in the adsorption of heavy metal mercury ions in aqueous solution.
8. The use according to claim 7, characterized in that The adsorption conditions include: the pH value of the aqueous solution is 3-7.