Preparation method and application of metal-organic dye adsorbent based on sulfonyl calixarene
Metal-organic dye adsorbents were prepared by self-assembly of sulfonylcalixarenes and transition metal nodes, which solved the problems of insufficient selectivity and complex synthesis of traditional adsorbents, and achieved efficient selective adsorption and simple preparation, making them suitable for dye wastewater treatment.
Patent Information
- Application Number
- CN202511402027.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-28
- Publication Date
- 2025-12-16
AI Technical Summary
Existing traditional adsorbents suffer from low adsorption capacity, high regeneration difficulty, and insufficient selectivity when treating dye wastewater. Furthermore, the traditional synthesis process is complex and cannot meet the needs of large-scale industrial applications.
A metal-organic dye adsorbent with a large central cavity and a peripheral cavity was prepared by self-assembly of sulfonyl calixarene with transition metal nodes and carboxylic acid bridging ligands. A polyhedral topology was constructed by a solvothermal directional assembly strategy.
It achieves significant selective adsorption capacity and high efficiency for dye molecules of different sizes, especially excellent adsorption effect on Congo red dye molecules. Moreover, the material has a stable structure, simple preparation method, and readily available raw materials, making it suitable for industrial applications.
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Figure CN121136112A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of preparation and application of metal-organic coordination supramolecular compounds, specifically relating to a method for preparing a metal-organic dye adsorbent based on sulfonylcalixarene and its application. Background Technology
[0002] In recent years, while technological advancements have boosted industrial productivity and improved the quality of life, they have also brought severe challenges to environmental protection, with wastewater pollution from synthetic dyes being particularly prominent. Many dye molecules have stable structures and can resist degradation by light, heat, and natural oxidants. If discharged directly into water bodies without effective treatment, they pose a serious threat to aquatic ecosystems and human health. Therefore, effectively removing these dyes from wastewater is crucial for protecting the ecological environment and human health.
[0003] Currently, researchers utilize methods such as reverse osmosis, coagulation-flocculation, biological treatment, ion exchange and advanced oxidation, membrane separation, and adsorption. Adsorption technology is particularly popular due to its simplicity, efficiency, ease of large-scale application, and effectiveness in removing trace amounts of water pollutants. For many years, traditional adsorbents such as activated carbon and zeolite have been widely used in wastewater treatment. However, these traditional adsorbents suffer from drawbacks such as low adsorption capacity, high regeneration difficulty, and insufficient selectivity. More importantly, these traditional adsorbents often require complex surface functionalization modifications to improve their adsorption performance. This multi-step synthesis process is not only cumbersome but also leads to high production costs, making it difficult to meet the demands of large-scale industrial applications.
[0004] Metal-organic coordination molecular containers (MOCs), as a cutting-edge system in supramolecular chemistry, are driving the innovative development of smart materials with their precisely tunable topological architecture and multifunctional integration characteristics. These materials are based on a well-known class of giant ring containers—thio- or sulfonyl calix[4] aromatics, which are self-assembled with transition metal nodes and carboxylic acid bridging ligands to construct nanostructures with confined cavities. Their unique metal active sites, functionalizable ligands and dynamic channel systems have shown multidimensional application potential in molecular recognition, catalytic conversion and nano-drug delivery. Studies have shown that the tetranuclear cluster units capped with sulfonyl calix aromatics endow MOCs with excellent coordination directionality. By controlling the geometric parameters of carboxylic acid ligands (such as bond angle and conjugation length), the precise construction of polyhedral topologies such as cubes and prisms can be achieved.
[0005] However, although some sulfonyl calix [4] aromatic MOCs have been applied to porous materials in separation science, examples of using cylindrical molecular cages for dye adsorption are still limited. How to balance pore accessibility and structural stability with supramolecular engineering strategies to develop novel MOCs that combine high separation performance with industrial applicability remains a key scientific problem that needs to be solved in this field. Summary of the Invention
[0006] The purpose of this invention is to overcome the above-mentioned problems in the traditional technology and provide a method for preparing a metal-organic dye adsorbent based on sulfonylcalixarene and its application. The metal-organic dye adsorbent is synthesized by coordination assembly of p-tert-butylsulfonylcalixarene[4]arene, 4,4'-dithiodibenzoic acid and nickel nitrate. In addition, the metal-organic dye adsorbent can be used for the adsorption and separation of dye molecules and has great industrial application value and practical prospects.
[0007] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:
[0008] This invention provides a method for preparing a metal-organic dye adsorbent based on sulfonylcalixarene, comprising the following steps:
[0009] S1. Using thiacalix[4] aromatics and sodium perborate as raw materials, dissolve them in chloroform; raise the temperature of the system to 38-42℃ and add glacial acetic acid dropwise, then raise the temperature to 48-52℃ and maintain it for 12-24h; after the reaction is completed, add distilled water and stir for 20-40min, then use small amounts of chloroform to extract and separate the mixture; take the organic layer and dry it with anhydrous sodium sulfate, filter it, concentrate the filtrate by rotary evaporation until solid precipitation, add methanol, filter and dry to obtain white solid;
[0010] S2. Using 4-mercaptobenzoic acid as a raw material, methanol was added and stirred; triethylamine was added to the system and reacted for 1.5–3 h; hydrogen peroxide was added dropwise at 4–6 °C, and then the temperature was raised to room temperature and reacted for 20–40 min; then concentrated hydrochloric acid was added dropwise at 4–6 °C and stirred for 6–12 min; the system was heated to room temperature and water was added and reacted for 0.5–2 h; after the reaction was completed, the mixture was washed with plenty of water until neutral, and dried to obtain a white solid.
[0011] S3. Place the products prepared in steps S1 and S2 into glass bottles, add N,N'-dimethylformamide, dissolve, and then add nickel nitrate hexahydrate, methanol, and acetonitrile; react in an oven for a period of time and then cool to room temperature, green crystals precipitate out; wash with methanol and diethyl ether, and dry to obtain a metal-organic dye adsorbent based on sulfonylcalixarene.
[0012] Further, in step S1, the mass ratio of the reactants of thiacalix[4] aromatics and sodium perborate is 1:2; the volume ratio of chloroform and glacial acetic acid is 3:5.
[0013] Furthermore, in step S1, vacuum concentration is used when concentrating the filtrate. The conditions for vacuum concentration are that the temperature is not higher than 40°C and the vacuum degree is 0.09 to 0.1 MPa.
[0014] Furthermore, in step S2, the volume ratio of methanol, triethylamine, hydrogen peroxide, and concentrated hydrochloric acid is 75:5:1:4.
[0015] Furthermore, in step S2, the concentration of concentrated hydrochloric acid is 12 mol / L.
[0016] Further, in step S3, the volume ratio of N,N'-dimethylformamide, methanol, and acetonitrile is 9:4:1.
[0017] Furthermore, in step S3, the molar ratio of the product prepared in step S1, the product prepared in step S2, and nickel nitrate hexahydrate is 1:2:4.
[0018] Furthermore, in step S3, the solvothermal temperature is 100–140°C, and the reaction time is 12–16 h.
[0019] The present invention also provides a metal-organic dye adsorbent based on sulfonylcalixarene, which is prepared according to the above preparation method.
[0020] This invention also provides the application of sulfonylcalixarene-based metal-organic dye adsorbents in the field of dye molecule adsorption.
[0021] The beneficial effects of this invention are:
[0022] 1. The metal-organic dye adsorbent prepared in this invention is based on a sulfonylcalixarene structure. This metal-organic dye adsorbent contains a large central cavity and two symmetrically distributed peripheral cavities. This special cavity structure endows it with excellent adsorption performance. This dye adsorbent exhibits significant selective adsorption capacity for dye molecules of different sizes, providing a new research idea for the development of highly efficient selective adsorption materials.
[0023] 2. The metal-organic dye adsorbent based on sulfonylcalixarene of this invention has a novel structure, being a cylindrical metal-organic molecular cage. Its characteristic structure includes a significant inner cavity and two symmetrically distributed outer cavities. This unique cavity structure endows the material with excellent adsorption performance. Experimental results show that it exhibits strong adsorption capacity and significant selective adsorption characteristics for dye molecules. Based on these excellent performance characteristics, this material shows significant application potential in the adsorption-separation of dye molecules.
[0024] 3. The preparation method of the present invention is simple, the raw materials are readily available, the yield is high, the structure is stable, the adsorption effect is good, and the selectivity is high.
[0025] Of course, any product implementing this invention does not necessarily need to achieve all of the above advantages at the same time. Attached Figure Description
[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 The powder X-ray diffraction pattern of the sulfonylcalixarene-based metal-organic dye adsorbent prepared in Example 3;
[0028] Figure 2 Crystal structure diagram;
[0029] Among them, (a) is the crystal structure diagram of the metal-organic dye adsorbent based on sulfonylcalixarene prepared in Example 3, and (b) is the crystal structure diagram of the metal-organic dye adsorbent based on sulfonylcalixarene with cavities marked by two colored spheres.
[0030] Figure 3 The structure diagram of the metal-organic dye adsorbent based on sulfonylcalixarene;
[0031] Among them, (a) is a two-dimensional structural diagram of the metal-organic dye adsorbent based on sulfonylcalixarene prepared in Example 3, and (b) is a three-dimensional structural diagram of the metal-organic dye adsorbent based on sulfonylcalixarene prepared in Example 3.
[0032] Figure 4 The infrared spectrum of the metal-organic dye adsorbent based on sulfonylcalixarene prepared in Example 3;
[0033] Figure 5 The N2 adsorption isotherm and pore size distribution of the sulfonylcalixarene-based metal-organic dye adsorbent prepared in Example 3 at 77 K;
[0034] Figure 6 The UV-Vis spectra of the metal-organic dye adsorbent based on sulfonylcalixarene prepared in Example 3 before and after the addition of Rhodamine B aqueous solution are shown.
[0035] Figure 7 The UV-Vis spectra of the metal-organic dye adsorbent based on sulfonylcalixarene prepared in Example 3 before and after the addition of eosin Y aqueous solution are shown.
[0036] Figure 8 The UV-Vis spectra of the metal-organic dye adsorbent based on sulfonylcalixarene prepared in Example 3 before and after the addition of Congo red aqueous solution are shown in the inset.
[0037] Figure 9 A schematic diagram showing the adsorption performance of Congo red by a metal-organic dye adsorbent based on sulfonylcalixarene.
[0038] Among them, (a) is the kinetic distribution diagram of Congo red adsorption by the sulfonyl calixarene-based metal-organic dye adsorbent prepared in Example 3; (b) is the linear fitting adsorption rate constant (5.2 × 10⁻⁶) of Congo red adsorption by the sulfonyl calixarene-based metal-organic dye adsorbent prepared in Example 3. -5 min -1 )picture;
[0039] Figure 10 The UV-Vis spectra of the metal-organic dye adsorbent based on sulfonylcalixarene prepared in Example 3 before and after the addition of Congo Red / Rhodamine B mixed aqueous solution are shown. Detailed Implementation
[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0041] This invention discloses a method for preparing a metal-organic dye adsorbent based on a sulfonylcalixarene structure and its application in dye molecule adsorption-separation. Using Ni(II) as the metal node, and utilizing the synergistic coordination between the dicarboxylic acid ligand 4,4'-dithiodibenzoic acid and p-tert-butylsulfonylcalixarene [4]arene (H4TBSC), a sulfonylcalixarene-based metal-organic dye adsorbent with clearly defined inner and outer cavity partitions was successfully constructed through a solvothermal directional assembly strategy. This adsorbent material contains a large central cavity and two symmetrically distributed peripheral cavities. This special structure gives it excellent selective adsorption performance for Congo red (CR) dye molecules. It can also achieve efficient separation of the Congo red / Rhodamine B (RhB) mixed system through molecular size sieving. Compared with the prior art, the adsorbent material provided by this invention has the following outstanding advantages: simple preparation process, readily available raw materials, good structural stability, high selectivity, and large adsorption capacity. This invention provides a new idea and method for developing multifunctional supramolecular adsorbent materials based on dynamic coordination engineering, and has broad application prospects in the fields of dye separation and wastewater treatment.
[0042] Example 1
[0043] A method for preparing tert-butylthiacalixarene includes the following steps:
[0044] Thiacalix[4] aromatic hydrocarbon (2g, 2.76mmol) and sodium perborate (4g, 2.6mmol) were used as raw materials and placed in a 250mL double-necked flask containing 60mL of chloroform. After the system temperature was raised to 38-42℃, 100mL of glacial acetic acid was added dropwise, and then the temperature was raised to 48-52℃ and maintained for 18h. After the reaction was completed, 50mL of distilled water was added and stirred for 30min, and then 100mL of distilled water was added. The mixture was extracted and separated three times with 120mL of chloroform, 40mL each time. The organic layer was dried with anhydrous sodium sulfate, filtered, and the filtrate was concentrated by rotary evaporation until a solid precipitated. 500mL of methanol was added, and after filtration and drying, a white solid was obtained.
[0045] Example 2
[0046] The preparation method of 4,4'-dithiodibenzoic acid includes the following steps:
[0047] 540 mg (3.5 mmol) of 4-mercaptobenzoic acid was placed in a 50 mL round-bottom flask, and 15 mL of methanol was added and stirred. 1 mL of triethylamine was added to the system and the reaction proceeded for 2 h. 0.2 mL of hydrogen peroxide was added dropwise at 5 °C, and the mixture was heated to room temperature and reacted for 30 min. Subsequently, 0.8 mL of concentrated hydrochloric acid was added dropwise at 5 °C and stirred for 10 min. The system was then heated to room temperature, and 30 mL of water was added, and the reaction proceeded for 1 h. After the reaction was complete, the mixture was washed with 500 mL of water until neutral, and dried to obtain a white solid.
[0048] Example 3
[0049] A method for preparing a metal-organic dye adsorbent based on sulfonylcalixarene includes the following steps:
[0050] The product prepared in Example 1 (4.25 mg, 0.005 mmol) and the product prepared in Example 2 (3.1 mg, 0.01 mmol) were placed in a 10 mL glass bottle. After dissolving in 0.5 mL of N,N'-dimethylformamide (DMF), nickel nitrate hexahydrate (5.8 mg, 0.02 mmol) was added, followed by 0.2 mL of methanol and 0.05 mL of acetonitrile. The mixture was placed in a 100 °C oven and reacted for 12 h. Afterward, it was removed and slowly cooled to room temperature, resulting in the precipitation of green single crystals. These crystals were washed at least three times with methanol and diethyl ether, respectively. The crystals were then dried to obtain green crystals. Yield: 88%. IR (KBr pellet, cm⁻¹) -1):v=3434.78(w),2958.89(m),1655.51(m),1588.65(s),1484.03(s),1412.45(s),1262.21(m),1124.5 6(m),1078.93(m),1003.42(w),898.80(w),836.66(w),802.04(w),756.08(w),560.57(w),560.57(m).
[0051] The spectrum and structure of the metal-organic dye adsorbent based on sulfonylcalixarene prepared in Example 3 are as follows: Figures 1-5 As shown.
[0052] Example 4
[0053] Comparative experiment of the adsorption performance of three dye molecules by the sulfonylcalixarene-based metal-organic dye adsorbent from Example 3:
[0054] At 25°C, the activated green crystals obtained in Example 3 (1.7 mg, 5 × 10⁻⁶) were subjected to [further treatment]. -4 Rhodamine B (0.05 mM), eosin Y (0.05 mM), and Congo red (0.2 mM) were dispersed in 10 mL of aqueous solutions of three dyes, respectively. The adsorption process was quantitatively analyzed by time-resolved UV-Vis spectroscopy (monitoring wavelengths: CR: 496 nm, EY: 515 nm, RhB: 554 nm). Results are as follows: Figures 6-8 As shown, its adsorption of Congo red reached dynamic equilibrium within 180 min, with a maximum adsorption capacity as high as 792.4 mg / g. In contrast, the absorbance of Rhodamine B and Eosin Y remained almost unchanged even after 12 h of soaking, exhibiting a significant size sieving effect. The dynamic adsorption mechanism of Congo red was revealed through kinetic experiments. The adsorption rate was relatively fast in the initial adsorption stage (0-120 min), gradually stabilizing after 120 min, and gradually reaching saturation within 180 min. Figure 9 a). During the experiment, the color of the solution also changed from red to almost colorless. Figure 8 (Illustration). A pseudo-second-order kinetic model was used to fit the data, yielding a rate constant k = 5.20 × 10³ g / (mg·min) and a goodness-of-fit R² = 0.997. Figure 9 b).
[0055] Example 5
[0056] Adsorption and separation experiment of Congo Red / Rhodamine B mixed solution by metal-organic dye adsorbent based on sulfonylcalixarene from Example 3:
[0057] At 25°C, the green crystals obtained in Example 3 (1.7 mg, 5 × 10⁻⁶) were subjected to [a process described in the original text]. -4 (mmol) was dispersed in 10 mL of an aqueous solution of Congo red / Rhodamine B at a mass ratio of 6:1 (concentrations of 72 mg / L and 12 mg / L, respectively). The adsorption process was quantitatively analyzed by time-resolved UV-Vis spectroscopy (monitoring wavelengths CR: 496 nm, EY: 515 nm, RhB: 554 nm). The original solution exhibited dual characteristic absorptions at 496 nm (characteristic peak of Congo red molecules) and 554 nm (characteristic peak of Rhodamine B molecules). As the adsorption process proceeded, the peak corresponding to Rhodamine B remained almost unchanged, while the intensity of the characteristic peak of Congo red completely disappeared, successfully achieving precise separation of the binary system of Congo red / Rhodamine B. Figure 10 ).
[0058] In summary, the above implementation examples are based on the preparation method of metal-organic dye adsorbents using sulfonylcalixarenes. By synthesizing p-tert-butylsulfonylcalix[4]arene, adding 4,4'-dithiodibenzoic acid and coordinating with nickel nitrate, the metal-organic dye adsorbent is finally obtained. The metal-organic dye adsorbent of the present invention is a hierarchical porous material with a special structure. These discrete molecular cages can self-assemble into a supramolecular framework with a three-dimensional porous structure through abundant intermolecular CH···S hydrogen bond interactions. Most notably, the metal-organic dye adsorbent of the present invention exhibits extremely high adsorption capacity for Congo red and good selective separation performance for Congo red / Rhodamine B dye mixtures. This discovery not only provides an efficient and feasible strategy for constructing molecular cages based on sulfonylcalix[4]arenes, but also lays a solid theoretical foundation for the practical application of this type of new material in complex wastewater treatment, dye separation and other related fields, showing broad application prospects.
[0059] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A method for preparing a metal-organic dye adsorbent based on sulfonylcalixarene, characterized in that, Includes the following steps: S1. Using thiacalix[4] aromatics and sodium perborate as raw materials, dissolve them in chloroform; raise the temperature of the system to 38-42℃ and add glacial acetic acid dropwise, then raise the temperature to 48-52℃ and maintain it for 12-24h; after the reaction is completed, add distilled water and stir for 20-40min, then use small amounts of chloroform to extract and separate the mixture; take the organic layer and dry it with anhydrous sodium sulfate, filter it, concentrate the filtrate by rotary evaporation until solid precipitation, add methanol, filter and dry to obtain white solid; S2. Using 4-mercaptobenzoic acid as a raw material, methanol was added and stirred; triethylamine was added to the system and reacted for 1.5–3 h; hydrogen peroxide was added dropwise at 4–6 °C, and then the temperature was raised to room temperature and reacted for 20–40 min; then concentrated hydrochloric acid was added dropwise at 4–6 °C and stirred for 6–12 min; the system was heated to room temperature and water was added and reacted for 0.5–2 h; after the reaction was completed, the mixture was washed with plenty of water until neutral, and dried to obtain a white solid. S3. Place the products prepared in steps S1 and S2 into glass bottles, add N,N'-dimethylformamide, dissolve, and then add nickel nitrate hexahydrate, methanol, and acetonitrile; react in an oven for a period of time and then cool to room temperature, green crystals precipitate out; wash with methanol and diethyl ether, and dry to obtain a metal-organic dye adsorbent based on sulfonylcalixarene.
2. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of the reactants of thiacalix[4]arene and sodium perborate is 1:2; the volume ratio of chloroform and glacial acetic acid is 3:
5.
3. The preparation method according to claim 1, characterized in that, In step S1, vacuum concentration is used to concentrate the filtrate. The conditions for vacuum concentration are: temperature not higher than 40°C and vacuum degree 0.09-0.1 MPa.
4. The preparation method according to claim 1, characterized in that, In step S2, the volume ratio of methanol, triethylamine, hydrogen peroxide, and concentrated hydrochloric acid is 75:5:1:
4.
5. The preparation method according to claim 1, characterized in that, In step S2, the concentration of concentrated hydrochloric acid is 12 mol / L.
6. The preparation method according to claim 1, characterized in that, In step S3, the volume ratio of N,N'-dimethylformamide, methanol, and acetonitrile is 9:4:
1.
7. The preparation method according to claim 1, characterized in that, In step S3, the molar ratio of the product prepared in step S1, the product prepared in step S2, and nickel nitrate hexahydrate is 1:2:
4.
8. The preparation method according to claim 1, characterized in that, In step S3, the solvothermal temperature is 100–140°C, and the reaction time is 12–16 h.
9. A metal-organic dye adsorbent based on sulfonylcalixarene, prepared according to any one of claims 1-8.
10. The application of the sulfonylcalixarene-based metal-organic dye adsorbent according to claim 9 in the field of dye molecule adsorption.