Multifunctional hydrogel and application thereof

Abstract

The invention discloses a multifunctional hydrogel which comprises polyethylene glycol diacrylate, methacrylated beta-cyclodextrin and a zwitterionic monomer, and the zwitterionic monomer is sulfobetaine methacrylate or [2-(methacryloyloxy) ethyl] dimethyl (3-sulfopropyl) ammonium salt; wherein the mass percentage of the polyethylene glycol diacrylate is 1-30%, the mass percentage of the zwitterionic monomer is 10-30%, and the mass percentage of the methacrylated beta-cyclodextrin is 1-5%. According to the invention, a polyethylene glycol diacrylate cross-linked skeleton is combined with a zwitterionic monomer to enhance hydrophilicity and ion complexing ability, so that a large-mesh structure is formed; and the beta-cyclodextrin derivative is selectively combined with the aromatic organic pollutants through the host-guest interaction. Through cooperation of multifunctional sites, dyes, drugs, metals and micro-plastics are removed at the same time. The multifunctional hydrogel disclosed by the invention has the advantages that the pollutant removal rate is increased, and the multifunctional hydrogel has reproducibility and can be applied to various water treatment processes.

Description

Technical Field

[0001] This invention belongs to the field of hydrogel preparation technology, specifically relating to a multifunctional hydrogel and its application in removing micropollutants and microplastics from water. Background Technology

[0002] In recent years, trace pollutants such as pharmaceuticals, pesticide metabolites, and plastic additives have been widely detected in rivers, lakes, and tap water. Although their concentrations are only at the ppb level, long-term exposure can cause ecotoxicity and human health risks. For example, bisphenol A (BPA) causes endocrine disorders, ethinyl estradiol (EE2) affects fish reproduction, and heavy metals (Pb) can cause other health problems. 2+ Cu 2+ Fe 3+ Microplastics can cause neurotoxicity and kidney damage; micro / nanoplastics with a diameter of 100-5 µm are difficult to remove due to their small size and can enter the body and even the bloodstream, posing a potential health threat. Microplastics also act as pollutant carriers, adsorbing drug residues, dyes, and heavy metals, increasing their environmental persistence and bioavailability.

[0003] Traditional adsorption materials such as activated carbon and ion exchange resins are usually used alone, each with its own drawbacks. For example, activated carbon is effective for hydrophobic organic matter, but has low removal rates for polar molecules and metal ions and slow kinetics. Ion exchange resins, on the other hand, have high selectivity, but are insufficient for removing complex mixed pollutants. β-cyclodextrin polymers adsorb small organic molecules through host-guest interactions, but have slow adsorption rates and low mechanical strength. Nanofiltration / reverse osmosis membranes can intercept some pollutants, but have high energy consumption, are prone to fouling, and have high operating costs.

[0004] Existing technologies for designing zwitterionic hydrogels with a PSB framework can simultaneously remove organic and metallic contaminants at a rate 10 times faster than activated carbon. However, this material still has limitations in terms of contaminant treatment, such as its inability to handle microplastics; furthermore, the chelating units are primarily DTPA-based, resulting in high costs. Therefore, there is an urgent need to develop a composite hydrogel that combines cyclodextrin host-guest recognition, zwitterionic complexation, hydrophobic micelle enrichment, and polyphenol chelation, achieving both high-efficiency removal of multiple contaminants and recyclability, while maintaining stable performance in real, complex aquatic environments. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems and provide a multifunctional hydrogel that can effectively and rapidly remove a variety of pollutants. Another purpose of this invention is to provide its applications.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A multifunctional hydrogel comprising the following components: Crosslinking backbone: polyethylene glycol diacrylate (PEGDA); Recognition unit: β-cyclodextrin methacrylated (β-CD-MA); zwitterionic monomers: sulfobetaine methacrylate (SBMA) or [2-(methacryloyloxy)ethyl]dimethyl(3-sulfopropyl)ammonium salt (PSB); The content of polyethylene glycol diacrylate (PEGDA) is 1-30% by mass, the content of zwitterionic monomer is 10-30% by mass, and the content of recognition unit β-CD-MA is 1-5% by mass.

[0007] Furthermore, the multifunctional hydrogel also includes a chelating unit, which is diethylenetriaminepentaacetic acid acrylamide (DTPA-AA) or methacrylamide tannic acid (TA-MA); the mass percentage of the chelating unit is 1~5%.

[0008] Furthermore, the multifunctional hydrogel also includes a hydrophobic unit, which is F127-diacrylate (F127-DA), and the mass percentage of F127-DA is 5~20%.

[0009] Furthermore, it is prepared by dissolving the components of the multifunctional hydrogel in a mixed solvent of water and ethanol; and then adding an initiator for polymerization.

[0010] Furthermore, the initiator is a photoinitiator, specifically Irgacure 2959, and its mass percentage in the multifunctional hydrogel is 0.1-0.5%.

[0011] Furthermore, the photoinitiator is activated under ultraviolet light at a wavelength of 365-405 nm.

[0012] Furthermore, the hydrogel can be prepared as tablets, microspheres, or column bed packing.

[0013] This invention seeks to protect the application of the above-described multifunctional hydrogel in the treatment of municipal drinking water, domestic water or industrial wastewater or in the preparation of equipment for the treatment of municipal drinking water, domestic water or industrial wastewater.

[0014] Furthermore, the water treatment involves removing organic micro-pollutants, heavy metal ions, or microplastic particles from the water body, wherein the microplastic particles are polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET), or polypropylene (PP).

[0015] This invention provides a method for regenerating the above-mentioned multifunctional hydrogel, which uses an alcohol solution or an acidified salt to elute organic micropollutants, heavy metal ions or microplastic particles in water.

[0016] Compared with the prior art, the present invention has the following technical effects: (1) This invention imparts mechanical strength and transparency to the hydrogel through a PEGDA crosslinking backbone; enhances hydrophilicity and ion complexation ability through zwitterionic monomers (SBMA / PSB) to form a large-pore structure and accelerate mass transfer; and utilizes the recognition unit β-cyclodextrin derivative (β-CD-MA) to selectively bind aromatic organic pollutants (such as bisphenol A and dye molecules) through host-guest interactions. The synergistic effect of multifunctional sites overcomes the difficulty of compatibility and binding, achieving "one material with multiple functions", and can simultaneously remove dyes, drugs, metals and microplastics.

[0017] (2) The present invention further enhances the particle capture ability by using chelating unit DTPA-AA: a strong metal chelating agent; TA-MA: modified from tannic acid, which can both complex metal ions and interact with the surface of microplastics π-π; and by using hydrophobic unit (F127-DA): self-assembled into micelle core in hydrogel, which is used to enrich insoluble organic pollutants and plastic additives.

[0018] (3) The multifunctional hydrogel of the present invention improves the pollutant removal rate: the mass transfer is fast and the removal is completed within 10 to 20 minutes; and it is regenerable: it can be recycled by elution with ethanol and acidified salt water, and can be prepared into tablets and column beds to adapt to a variety of water treatment processes. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the hydrogel preparation process.

[0020] Figure 2 This is an SEM image of the hydrogel from Example 7.

[0021] Figure 3 This refers to the hydrogel regeneration cycle performance of Example 7. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and medicines involved in the embodiments of the present invention are commercially available and can be obtained and used by those skilled in the art through well-known channels.

[0023] Example 1: PEGDA-βCD-based hydrogel Formula: 20% polyethylene glycol diacrylate (PEGDA), 3% methacrylamide β-cyclodextrin (β-CD-MA), 0.3% photoinitiator Irgacure 2959, and the balance being an aqueous ethanol solution.

[0024] Preparation process: combined with the attached Figure 1 The preparation method involves adding a photoinitiator to a prepared monomer solution, then reacting it in a microfluidic / mold, followed by curing and drying to obtain a transparent hydrogel. Specifically, 20 g of PEGDA was weighed, 3 g of β-CD-MA was added, and then solvent (70% water, 30% ethanol solution) was added to bring the volume to 100 mL, and the mixture was stirred evenly. Irgacure 2959 (0.3 wt%) was added, and the mixture was cured under ultraviolet light irradiation (365 nm, 10 min). The cured gel was then dried to form a transparent hydrogel.

[0025] Example 2: PEGDA-SBMA hydrogel Formula: PEGDA 20%, sulfobetaine methacrylate 20%, initiator 0.3%.

[0026] Preparation process: Weigh 20 g of PEGDA, add 20 g of sulfobetaine methacrylate (SBMA), and then add solvent (70% water, 30% ethanol solution), and mix thoroughly. Add photoinitiator Irgacure 2959 (0.3 wt%), and cure under ultraviolet light irradiation (365 nm, 10 min). The cured gel is dried to form a transparent hydrogel.

[0027] Example 3: PEGDA-βCD-SBMA hydrogel Formulation: PEGDA 20%, SBMA 20%, β-CD-MA 3%, initiator 0.3%.

[0028] Preparation process: Weigh 20 g of PEGDA, add 20 g of SBMA, then add 3 g of β-CD-MA, and then add solvent (70% water, 30% ethanol solution), and mix well. Add photoinitiator Irgacure 2959 (0.3 wt%), and cure under ultraviolet light irradiation (365 nm, 10 min). The cured gel is dried to form a transparent hydrogel.

[0029] Example 4: PEGDA-βCD-SBMA-F127 hydrogel Formulation: PEGDA 20%, SBMA 20%, β-CD-MA 3%, F127-DA 15%, initiator 0.3%.

[0030] Preparation process: Weigh 20 g of PEGDA, add 20 g of SBMA, 3 g of β-CD-MA, and 15 g of F127-diacrylate sequentially, then add solvent (70% water, 30% ethanol solution) and mix thoroughly. Add photoinitiator Irgacure 2959 (0.3 wt%) and cure under ultraviolet light irradiation (365 nm, 10 min). Dry the cured gel to form a transparent hydrogel.

[0031] Example 5: PEGDA-βCD-SBMA-TA hydrogel Formulation: PEGDA 20%, SBMA 15%, β-CD-MA 3%, TA-MA 2%, initiator 0.3%.

[0032] Preparation process: Weigh 20 g of PEGDA, add 15 g of SBMA, 3 g of β-CD-MA, and 2 g of methacryloyl tannic acid (TA-MA) sequentially, then add solvent (70% water, 30% ethanol solution) and mix thoroughly. Add photoinitiator Irgacure2959 (0.3 wt%) and cure under ultraviolet light irradiation (365 nm, 10 min). The cured gel is dried to form a transparent hydrogel.

[0033] Example 6: PEGDA-βCD-SBMA-DTPA hydrogel Formulation: PEGDA 20%, SBMA 20%, β-CD-MA 3%, DTPA-AA 2%, initiator 0.3%.

[0034] Preparation process: Weigh 20 g of PEGDA, add 20 g of SBMA, 3 g of β-CD-MA, and 2 g of diethylenetriaminepentaacetic acid acrylamide (DTPA-AA) sequentially, then add solvent (70% water, 30% ethanol solution) and mix thoroughly. Add photoinitiator Irgacure 2959 (0.3 wt%) and cure under ultraviolet light irradiation (365 nm, 10 min). The cured gel is dried to form a transparent hydrogel.

[0035] Example 7: PEGDA-βCD-SBMA-F127-TA hydrogel (hydrogel of this invention) Formulation: PEGDA 20%, SBMA 18%, β-CD-MA 3%, F127-DA 15%, TA-MA 2%, initiator 0.3%.

[0036] Preparation process: Weigh 20 g of PEGDA, then add 18 g of SBMA, 3 g of β-CD-MA, 15 g of F127-diacrylate, and 2 g of methacrylamide tannic acid (TA-MA) sequentially. Add solvent (70% water, 30% ethanol solution) and mix thoroughly. Add photoinitiator Irgacure 2959 (0.3 wt%) and cure under UV irradiation (365 nm, 10 min). Dry the cured gel to form a transparent hydrogel, as shown in the SEM image below. Figure 2 As shown, a porous membrane structure is formed.

[0037] Example 8: PEGDA-βCD-SBMA-F127-DTPA hydrogel Formulation: PEGDA 20%, SBMA 18%, β-CD-MA 3%, F127-DA 15%, DTPA-AA 2%, initiator 0.3%.

[0038] Preparation process: Weigh 20 g of PEGDA, then add 18 g of SBMA, 3 g of β-CD-MA, 15 g of F127-diacrylate, and 2 g of diethylenetriaminepentaacetic acid acrylamide (DTPA-AA) sequentially. Add solvent (70% water, 30% ethanol solution) and mix thoroughly. Add photoinitiator Irgacure 2959 (0.3 wt%) and cure under ultraviolet light irradiation (365 nm, 10 min). Dry the cured gel to form a transparent hydrogel.

[0039] Example 9: PEGDA-βCD-SBMA-(TA + DTPA) hydrogel Formulation: PEGDA 20%, SBMA 18%, β-CD-MA 3%, TA-MA 1% + DTPA-AA 1%, initiator 0.3%.

[0040] Preparation process: Weigh 20 g of PEGDA, then add 18 g of SBMA, 3 g of β-CD-MA, 1 g of methacryloyl tannic acid (TA-MA), and 1 g of diethylenetriaminepentaacetic acid acrylamide (DTPA-AA) sequentially. Add solvent (70% water, 30% ethanol solution) and mix thoroughly. Add photoinitiator Irgacure 2959 (0.3 wt%) and cure under ultraviolet light irradiation (365 nm, 10 min). Dry the cured gel to form a transparent hydrogel.

[0041] Example 10: PEGDA-βCD-PSB-F127-TA hydrogel Formulation: PEGDA 20%, PSB 18%, β-CD-MA 3%, F127-DA 15%, TA-MA 2%, initiator 0.3%.

[0042] Preparation process: Weigh 20 g of PEGDA, add 18 g of [2-(methacryloyloxy)ethyl]dimethyl(3-sulfopropyl)ammonium salt, 3 g of β-CD-MA, 15 g of F127-diacrylate, and 2 g of methacryloyl tannic acid (TA-MA) sequentially, then add solvent (70% water, 30% ethanol solution) and mix thoroughly. Add photoinitiator Irgacure 2959 (0.3 wt%) and cure under ultraviolet light irradiation (365 nm, 10 min). The cured gel is dried to form a transparent hydrogel.

[0043] Example 11: PEGDA-βCD (bulk phase) + surface grafted SBMA (secondary modification) Preparation process: First, prepare PEGDA-βCD gel (Example 1); immerse the gel in SBMA (20%) and MABA (0.2%) in an initiator solution, and perform photo / thermal initiation of surface grafting; wash with water to remove residue.

[0044] Test Example 1 1. Testing Method The wastewater used in this test was artificial wastewater, containing common water pollutants (such as bisphenol A, estrogen EE2, and heavy metal ions Pb²). + Cu² + Fe³ + (and microplastic particles). Organic pollutants: Bisphenol A and estrogen EE2 were used as model pollutants; metal ions: Pb²⁺ was used. + Cu² + Fe³ + Solution. Microplastics: PS / PET 100 nm–1 µm (fluorescently labeled), NTA / μ-Raman quantification. Wastewater pollutant concentrations: BPA: 50 ppm, EE2: 20 ppb, Pb² + 200 ppb, microplastics: 1 ppm, to determine the removal efficiency of the hydrogel. Sample preparation: The sample was prepared into a hydrogel sheet with a radius of 1 cm and a thickness of 0.5 cm. Wastewater and hydrogel were mixed at a mass ratio of 10:1. The water sample (containing pollutants) was contacted with the hydrogel for 10 min, and the concentration of residual pollutants was determined.

[0045] 2. Test Results The experimental results are shown in Table 1. Table 1 shows that the PEGDA-βCD hydrogel in Example 1 has a certain effect on the adsorption of bisphenol A, but its ability to remove metals is weak, especially for heavy metal ions (such as Pb²⁺). + Cu² + Example 2: The hydrogel PEGDA-SBMA has an amphoteric framework. The introduction of SBMA makes the hydrogel highly hydrophilic in water, effectively binding with metal ions (Pb²⁺). + Cu² + Fe³ + This process forms a complex, significantly improving the removal capacity for heavy metals. However, it is relatively weak in removing hydrophobic organic compounds (such as bisphenol A and EE2). Example 3: The PEGDA-βCD-SBMA hydrogel sample can effectively treat both metals and organic matter in wastewater treatment. This formulation, by combining cyclodextrin and zwitterionic monomers, enables the hydrogel to simultaneously and efficiently remove organic pollutants and metal ions, especially Pb²⁺. + The removal rate reached 94%. Example 4: The hydrogel PEGDA-βCD-SBMA-F127 for wastewater treatment utilizes F127 to form a micelle structure, enhancing the enrichment of hydrophobic organic pollutants (such as bisphenol A and EE2), thus significantly improving the removal efficiency of these pollutants. The removal rates of bisphenol A and EE2 are both >90%, while retaining the ability to remove metal ions. Example 5: The hydrogel PEGDA-βCD-SBMA-TA, through the polyphenolic structure of tannic acid (TA), can not only form complexes with metal ions but also enhance the removal efficiency of microplastics through π-π interactions and van der Waals forces with the microplastic surface. The microplastic removal efficiency is significantly improved, reaching 70%. Example 6: The hydrogel PEGDA-βCD-SBMA-DTPA exhibits strong heavy metal removal capacity in wastewater treatment, particularly for Pb²⁺. + The removal rate is close to 99%; In Example 7, the hydrogel PEGDA-βCD-SBMA-F127-TA, through the combination of F127 and TA, not only enhanced the removal capacity of organic matter (such as bisphenol A) but also achieved good results in microplastic removal (microplastic removal ≥80%). In Example 8, the hydrogel PEGDA-βCD-SBMA-F127-DTPA showed the best metal removal rate in wastewater treatment, approaching 95%. However, compared to Example 7, the microplastic removal effect was significantly reduced. In Example 9, the hydrogel PEGDA-βCD-SBMA-(TA+DTPA), due to the mixed effect of TA and DTPA, exhibited good metal and organic matter removal capabilities in wastewater treatment; however, its performance did not show a significant advantage compared to single chelating agents. Therefore, although this formulation has strong removal capabilities, the effect of mixed chelating agents is not necessarily better than using TA or DTPA alone. In Example 10, the hydrogel PEGDA-βCD-PSB-F127-TA exhibited lower performance in wastewater treatment compared to Example 7 because PSB was used as a zwitterionic monomer to replace SBMA. In Example 11, the hydrogel PEGDA-βCD (bulk phase) with surface-grafted SBMA demonstrated a certain ability to remove heavy metal ions in wastewater treatment while maintaining the basic functions of PEGDA-βCD.

[0046] Therefore, this invention endows the hydrogel with mechanical strength and transparency through a PEGDA crosslinking backbone; enhances hydrophilicity and ion complexation ability through zwitterionic monomers (SBMA / PSB), forming a large-pore structure to accelerate mass transfer; and utilizes the recognition unit β-cyclodextrin derivative (β-CD-MA) to selectively bind aromatic organic pollutants (such as bisphenol A and dye molecules) through host-guest interactions. The chelating units DTPA-AA (a strong metal chelating agent) and TA-MA (modified from tannic acid) can both complex metal ions and interact π-π with the microplastic surface, enhancing particle capture ability; and the hydrophobic unit (F127-DA) self-assembles into a micelle core within the hydrogel for enriching insoluble organic pollutants and plastic additives. The synergistic effect of these multifunctional sites overcomes the difficulties of compatibility and binding, achieving "one material, multiple functions," and can simultaneously remove dyes, drugs, metals, and microplastics.

[0047] Table 1. Removal rate of pollutants by different hydrogels (10 min)

[0048] Test Example 2 Regeneration Test 1. Testing Method Taking the hydrogel sample from Example 7 as an example, organic pollutants were eluted with 90% ethanol, followed by elution of metal ions with 10% NaCl + 1% HCl; microplastics were then eluted with water to obtain a regenerated hydrogel. This process was repeated after one round of filtration. The pollutant removal rate was retested after each round to ensure the regeneration performance and long-term effectiveness of the hydrogel.

[0049] 2. Test Results Experimental results are as follows Figure 3 As shown, after six consecutive regeneration cycles, the metal removal rate remained >90% and the organic matter removal rate remained >80%, demonstrating that the hydrogel possesses good renewability and stability. Combined with Test Example 1, it can be seen that this multifunctional hydrogel (Example 7) exhibits improved pollutant removal rate and rapid mass transfer, completing removal within 10-20 minutes; it also possesses renewability: it can be recycled and adapted to various water treatment processes, such as the preparation of filter membranes.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the solutions. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention based on the understanding of the present invention, without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multifunctional hydrogel, characterized in that, Includes the following components: Crosslinking backbone: polyethylene glycol diacrylate; Recognition unit: Methacrylamide β-cyclodextrin; zwitterionic monomers: sulfobetaine methacrylate or [2-(methacryloyloxy)ethyl]dimethyl(3-sulfopropyl)ammonium salt; The components include polyethylene glycol diacrylate (PEG) at a mass percentage of 1-30%, zwitterionic monomers at a mass percentage of 10-30%, and recognition units at a mass percentage of 1-5%.

2. The multifunctional hydrogel according to claim 1, characterized in that, The multifunctional hydrogel also includes chelating units, which are diethylenetriaminepentaacetic acid acrylamide or methacrylamide tannic acid; the mass percentage of the chelating units is 1~5%.

3. The multifunctional hydrogel according to claim 1, characterized in that, The multifunctional hydrogel also includes a hydrophobic unit, which is F127-diacrylate, and the mass percentage of F127-DA is 5~20%.

4. The multifunctional hydrogel according to any one of claims 1 to 3, characterized in that, The multifunctional hydrogel was prepared by dissolving its components in a mixture of water and ethanol; then adding an initiator for polymerization.

5. The multifunctional hydrogel according to claim 4, characterized in that, The initiator is a photoinitiator, specifically Irgacure 2959, and its mass percentage in the multifunctional hydrogel is 0.1-0.5%.

6. The multifunctional hydrogel according to claim 5, characterized in that, The photoinitiator is activated under ultraviolet light at a wavelength of 365-405 nm.

7. The multifunctional hydrogel according to claim 4, characterized in that, The hydrogel can be prepared as tablets, microspheres, or column bed packing.

8. The application of the multifunctional hydrogel according to claim 4 in the treatment of municipal drinking water, domestic water or industrial wastewater or in the preparation of equipment for the treatment of municipal drinking water, domestic water or industrial wastewater.

9. The application according to claim 8, characterized in that, The water treatment removes organic micro-pollutants, heavy metal ions, or microplastic particles from the water body. The microplastic particles are polystyrene, polyethylene, polyethylene terephthalate, or polypropylene.

10. The regeneration method of the multifunctional hydrogel according to claim 4, characterized in that, Use alcohol solutions or acidified salts to elute organic micropollutants, heavy metal ions, or microplastic particles from water.

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