Jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel and preparation and application thereof

Abstract

This invention discloses a method for preparing and applying a jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel, belonging to the field of hydrogel materials. The invention first mixes jellyfish polysaccharide with a sodium alginate solution, then drops the mixture into a chitosan solution. The mixture is continuously stirred at room temperature, undergoing self-assembly to form a spherical precursor, which is then solidified by calcium ion coordination to obtain the jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel material. This material possesses a three-dimensional porous network structure, rich in active groups such as amino, carboxyl, hydroxyl, and sulfate ester groups. It can adsorb suspended solids and antibiotics in wastewater through electrostatic and chelating interactions, significantly reducing wastewater turbidity and pollutants. The process conditions of this invention are mild, require no toxic crosslinking agents, are low-cost, and have good adsorption effects, making it highly promising for application in environmental engineering.

Description

Technical Field

[0001] This invention relates to the field of environmental protection materials and polymer composite materials technology, specifically to a jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel, its preparation method, and its application in the adsorption of pollutants in wastewater. Background Technology

[0002] With the development of industries such as aquaculture and modern medicine, antibiotics are frequently discharged into natural water bodies along with industrial wastewater. Meanwhile, polluted water bodies, such as aquaculture effluent, generally exhibit high turbidity, containing large amounts of suspended solids. These pollutants not only disrupt the structural and functional stability of aquatic ecosystems but may also accumulate and amplify through the food chain, posing a potential threat to human health. Therefore, developing cost-effective and efficient water treatment technologies to address these pollutants has become an urgent need in the field of water environment management.

[0003] Currently, treatment technologies for various pollutants such as antibiotics and suspended solids in water bodies mainly include advanced oxidation processes (AOPs), membrane filtration, biodegradation, and adsorption. Among these, AOPs have limitations such as high operating costs and the potential generation of toxic and harmful intermediates; membrane filtration generally carries the risk of membrane fouling and has high equipment maintenance costs; and biodegradation has poor tolerance to high concentrations and high toxicity of antibiotic wastewater, limiting its applicability. In contrast, adsorption technology, due to its advantages of simple operation, high treatment efficiency, low energy consumption, and no secondary pollution, has become one of the most promising technologies in the field of advanced wastewater treatment, and has been extensively studied for the separate removal of antibiotics and suspended solids.

[0004] Among numerous adsorption materials, hydrogel particles, due to their unique three-dimensional porous network structure, high porosity, and hydrophilicity, have shown application potential in capturing pollutants in water bodies. Natural polysaccharides such as chitosan and sodium alginate have become ideal substrates for preparing green hydrogels due to their advantages such as wide availability, biodegradability, and richness in active adsorption groups.

[0005] While the aforementioned natural polysaccharides are ideal materials for hydrogels, current technologies often rely on increasing the concentration of chemical cross-linking agents to improve the mechanical strength of hydrogels, but this sacrifices toughness and environmental adaptability. Furthermore, single polysaccharides often suffer from limited functional group diversity or uneven spatial distribution, making it difficult to achieve broad-spectrum synergistic adsorption of multiple target pollutants in complex water bodies. Current technologies have yet to solve the technical challenge of constructing a dense and stable three-dimensional interpenetrating network through multiple non-covalent bonds such as electrostatic interactions, hydrogen bonds, and hydrophobic interactions between polysaccharide molecules, thereby simultaneously improving the density of adsorption sites and the physical stability of the material.

[0006] In the processes of raw material extraction and gel network construction, existing technologies generally suffer from the following irreconcilable contradictions: Firstly, in current extraction processes for natural marine polysaccharides, traditional acid-base extraction or microwave / ultrasound-assisted extraction methods are prone to causing polysaccharide molecular chain breakage, sharp reduction in molecular weight, and loss of specific functional groups due to their drastic chemical or physical effects, directly weakening their gelling properties. Furthermore, conventional preliminary extraction processes often fail to completely remove the extremely high endogenous salt content and large amounts of impurities and proteins from fresh jellyfish tissue, resulting in low purity of the final polysaccharide and severe masking of active cross-linking sites. Currently, there is an urgent need in the field for a refined extraction process that is gentle, highly efficient in removing impurities and salts, and that can retain the spatial structure and activity of polysaccharide macromolecules to the greatest extent possible.

[0007] Secondly, in the design of hydrogel crosslinking mechanisms, existing high-strength crosslinked hydrogels heavily rely on chemical crosslinking agents (such as glutaraldehyde, epichlorohydrin, N,N'-methylenebisacrylamide, etc.). These reagents not only have high residual toxicity, causing secondary pollution to water bodies, but also have uncontrollable crosslinking reaction processes, high costs, and are extremely environmentally unfriendly. In contrast, while purely physical crosslinking, such as single sodium alginate-calcium ion coordination crosslinking, possesses green and environmentally friendly properties, the resulting gels have extremely low mechanical strength. In complex ionic water bodies, such as aquaculture wastewater rich in competing cations, ion exchange easily occurs, leading to network collapse or excessive swelling, making it impossible to achieve synergistic and sustained adsorption of multifunctional groups under harsh water conditions. Currently, there is an urgent need in the field for a particle preparation strategy that does not require the intervention of toxic crosslinking agents, has a mild and controllable preparation process, and can balance high adsorption capacity and long-term cycling stability.

[0008] While existing high-efficiency adsorption materials have excellent adsorption performance, their synthesis process is relatively complex, the raw materials are non-renewable, and their biodegradability is poor. Traditional physically cross-linked natural polysaccharide gels also face the dilemma of low mechanical strength, narrow adsorption spectrum, and easy collapse. While common chemically cross-linked natural polysaccharide hydrogels can effectively improve the mechanical strength and corresponding adsorption performance of hydrogels, they often come at the cost of environmental friendliness, which violates the principle of green development.

[0009] There is a clear technological gap in the existing technology: there is a lack of a novel hydrogel adsorption material that is all-natural polysaccharide-based, mildly prepared in pure aqueous phase, has absolutely zero toxic crosslinking agents, and possesses both ultra-large adsorption capacity and excellent regeneration cycle stability. Summary of the Invention

[0010] To overcome the shortcomings of existing technologies, this invention provides a jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel, its preparation method, and its application in the adsorption of pollutants in wastewater.

[0011] To achieve the above objectives, the present invention is implemented through the following technical solutions.

[0012] A jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel is obtained by self-assembly of jellyfish polysaccharide solution, sodium alginate solution and acidic chitosan solution, and by coordination crosslinking. In the hydrogel system, the jellyfish polysaccharide solution and sodium alginate solution are mixed in equal volumes, and the final mass fraction of the acidic chitosan solution in the system is 0.1%~1.0%.

[0013] Jellyfish polysaccharide solution was mixed with sodium alginate solution, and then the mixture was dropped into an acidic chitosan solution. The mixture was stirred continuously at room temperature and self-assembled to form a spherical precursor. Then, calcium ion coordination solidification was used to obtain jellyfish polysaccharide-sodium alginate-chitosan composite gel particles.

[0014] The jellyfish polysaccharide solution was prepared by dissolving the raw material after desalting, temperature-controlled enzymatic hydrolysis purification. The acidic chitosan solution is prepared by adding chitosan solid powder to deionized water, then adding organic acid and stirring continuously until completely dissolved.

[0015] The jellyfish polysaccharide solution is 1) Take sand jellyfish ( Nemopilema nomurai The umbrella cap is repeatedly soaked and washed with deionized water until desalted. Add 1 to 3 times the volume of deionized water according to the liquid-to-mass ratio (mL / g), and homogenize in an ice bath at high speed until it becomes a paste. 2) Adjust the pH of the above homogenate to 6.0~7.0 using a 0.5 M acetic acid-sodium acetate solution; 3) Add 1000~3000 U / g neutral protease to the above homogenate for enzymatic hydrolysis, and then place it in a 95~100℃ water bath for 10~15 min to inactivate it. 4) After inactivating the above enzyme hydrolysate, centrifuge at 8000~10000 r / min to remove impurities, and concentrate the supernatant under reduced pressure to 1 / 4~1 / 3 of the original volume; then centrifuge to collect the precipitate. 5) After redissolving the above precipitate, it is placed in a dialysis bag with a molecular weight cutoff of 8000~14000 Da and dialyzed at 4℃ for 48~72h. Finally, it is pre-frozen at -80℃ and freeze-dried under vacuum to obtain high-purity jellyfish polysaccharide freeze-dried powder. The dry powder is resuspended in water (to obtain a mass fraction of jellyfish polysaccharide of 0.1%~1.0% in the resuspension).

[0016] In step 3), add 1000~3000 U / g of neutral protease according to the wet weight of the jellyfish cap, and hydrolyze by shaking at 40~50℃ for 3~5 h.

[0017] In step 4), anhydrous ethanol pre-cooled to 4°C is slowly added dropwise to the concentrated product, and then the product is allowed to stand and age at 4°C for 12-24 hours; wherein the volume of anhydrous ethanol pre-cooled to 4°C added is 3-5 times the volume of the concentrated liquid.

[0018] The preparation process of the chitosan acidic solution is as follows: chitosan solid powder is added to deionized water, then glacial acetic acid is added and stirred continuously in a water bath at 30~60℃ until completely dissolved to obtain the chitosan acidic solution; wherein, the final mass fraction of chitosan in the chitosan acidic solution is 0.1%~1.0%, and the final mass fraction of glacial acetic acid is 1.0%~2.0%.

[0019] The sodium alginate solution is prepared by adding sodium alginate solid powder to water, and the mass fraction of sodium alginate in the solution is 0.1%~2.0%. A method for preparing the aforementioned jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel involves mixing a jellyfish polysaccharide solution with a sodium alginate solution, then dropping the mixture into an acidic chitosan solution, continuously stirring at room temperature to form a spherical precursor through self-assembly, and then coordinating and solidifying with calcium ions to obtain jellyfish polysaccharide-sodium alginate-chitosan composite gel particles.

[0020] To elaborate further: 1) Mix the jellyfish polysaccharide solution and sodium alginate solution in equal volume ratio (mix in equal volume under equal mass fraction) to obtain a jellyfish polysaccharide-sodium alginate mixture; 2) The mixture is added dropwise to the chitosan acidic solution, and under stirring conditions, the polyelectrolyte self-assembles to form a primary jellyfish polysaccharide-sodium alginate-chitosan composite gel particle suspension. 3) Add calcium chloride solution to the suspension for coordination crosslinking, and then prepare ternary composite hydrogel particles by static curing, separation and washing.

[0021] In step 2), the mixture is added dropwise to the acidic chitosan solution using a syringe. During the addition process, the stirring speed is maintained at 1000~1500 r / min, and the stirring time is 0.5~1.5 h.

[0022] After adding calcium chloride solution in step 3), continue stirring for 0.5 to 1.5 h, and then let it stand and solidify for 0.5 to 3.0 h. The ternary composite hydrogel particles with an average particle size of 2.0 to 4.0 mm are obtained by separation and washing.

[0023] An application of the aforementioned jellyfish polysaccharide-sodium alginate-chitosan composite gel particles, specifically their use as an adsorbent in the field of water treatment.

[0024] The jellyfish polysaccharide-sodium alginate-chitosan composite gel particles are used as adsorbents in the field of water treatment to adsorb and remove antibiotics and suspended pollutants from wastewater.

[0025] Compared with the prior art, the present invention has the following significant core advantages: The composite gel of this invention has a three-dimensional porous network structure and is rich in active groups such as amino, carboxyl, hydroxyl, and sulfate groups. It can adsorb suspended solids and antibiotics in wastewater through electrostatic and chelating interactions, significantly reducing wastewater turbidity and pollutants. Specifically: (1) This invention uses a preparation sequence of premixing sodium alginate and jellyfish polysaccharide, then adding chitosan, and finally adding calcium chloride. Based on the self-assembly mechanism of polyelectrolytes between natural polysaccharides and the coordination of metal ions, ternary hydrogel particles are prepared in one step. No toxic chemical cross-linking agents (such as glutaraldehyde) are required throughout the process, and the process parameters are mild and controllable, aligning with the concept of sustainable development.

[0026] (2) Jellyfish polysaccharide, sodium alginate and chitosan construct a three-dimensional porous network structure inside the particles. The three work together to provide multiple active sites such as carboxyl, hydroxyl, amino and sulfate groups, so that the composite particles have multiple adsorption mechanisms. Through synergistic mechanisms such as hydrogen bonding, electrostatic attraction and coordination chelation, small molecule antibiotics (such as chloramphenicol) and suspended pollutants can be captured simultaneously and efficiently to achieve broad-spectrum pollutant removal.

[0027] (3) Based on the dual cross-linking mechanism of "electrostatic composite-ion coordination", the physical toughness and chemical stability of the composite particles are enhanced. After multiple adsorption-desorption cycles, they can still maintain good morphological integrity and adsorption capacity, showing excellent regeneration performance. This process realizes the efficient conversion of marine waste jellyfish resources into high-value-added environmentally friendly materials, which has both economic and environmental benefits. Attached Figure Description

[0028] Figure 1 This is a graph showing the adsorption and removal rate of hydrogel particles in Example 1 and Comparative Example 1 when removing neutral small molecule chloramphenicol.

[0029] Figure 2 This is a graph showing the removal rate of suspended solids in high-turbidity actual water bodies by the hydrogel particles in Example 1 and Comparative Example 1 at different adsorption times.

[0030] Figure 3 The Fourier transform spectrum of the ternary composite hydrogel particles of jellyfish polysaccharide-sodium alginate-chitosan prepared in Example 1 of this invention is shown.

[0031] Figure 4 , 5 This is a scanning electron microscope image of the ternary composite hydrogel particles of jellyfish polysaccharide-sodium alginate-chitosan prepared in Example 1 of the present invention.

[0032] Figure 6 , 7 This is a scanning electron microscope image of the sodium alginate-chitosan binary composite hydrogel particles prepared in Comparative Example 1 of the present invention.

[0033] Figure 8 This is a comparison image of the ternary composite hydrogel particles of jellyfish polysaccharide-sodium alginate-chitosan prepared in Example 1 of the present invention before and after freeze-drying.

[0034] Figure 9 This is a comparison image of the sodium alginate-chitosan binary composite hydrogel particles prepared in Comparative Example 1 of this invention before and after freeze-drying. Detailed Implementation

[0035] The following examples further illustrate the specific implementation of the present invention, but the actual application and scope of protection of the present invention are not limited thereto. It should be emphasized that, in the following description, if there are processes not described in detail, these processes should be those that can be implemented or understood by those skilled in the art based on existing technology. Reagents or instruments whose manufacturers are not specifically specified are considered to be conventional products that can be obtained through commercial channels.

[0036] Based on the advanced guidance of "green chemistry and circular economy", this invention proposes for the first time to introduce novel jellyfish polysaccharides into the chitosan-sodium alginate system. By establishing the optimal preparation process and multiple non-covalent / coordinative synergistic crosslinking strategies, this invention does not use toxic chemical reagents, which is in line with the environmental protection concept of sustainable development. Furthermore, by constructing a three-dimensional interpenetrating network between polysaccharide molecules, it achieves a comprehensive leap in the material's mechanical strength and regeneration performance, resistance to environmental interference, and broad-spectrum targeted adsorption performance for adsorbing antibiotics, heavy metals and suspended solids in water.

[0037] Example 1 S1. Take jellyfish from the sand ( Nemopilema nomurai The umbrella cap is repeatedly soaked and washed with deionized water until desalted. 1 to 3 times the volume of deionized water is added according to the liquid-to-material volume ratio (mL / g) (2 times the volume is added in this example). The mixture is homogenized at high speed in an ice bath until it becomes a paste.

[0038] S2. Adjust the pH of the above homogenate to 7.0 using a 0.5 mol / L acetic acid-sodium acetate solution.

[0039] S3. Add 1500 U / g neutral protease to the above homogenate, and hydrolyze it by shaking at 45℃ and 150 r / min for 4 h, then inactivate it by placing it in a 95℃ water bath for 15 min.

[0040] S4. After inactivating the above enzymatic hydrolysate, centrifuge at 10000 r / min to remove impurities, concentrate the supernatant under reduced pressure to 1 / 3 of the original volume; slowly add 4 times the volume of pre-cooled anhydrous ethanol, let stand at 4℃ for 24 h, and collect the precipitate by centrifugation.

[0041] S5. After redissolving the above precipitate, it is placed in a dialysis bag with a molecular weight cutoff of 12000 Da, dialyzed at 4℃ for 48 h, and finally pre-frozen at -80℃ and freeze-dried under vacuum to obtain high-purity jellyfish polysaccharide freeze-dried powder.

[0042] S6. Add 0.5 g of lyophilized jellyfish polysaccharide powder to 50 mL of deionized water and stir magnetically to dissolve. This forms a 1.0% (w / w) jellyfish polysaccharide solution.

[0043] S7. Weigh 0.5 g of sodium alginate solid powder and dissolve it in 50 mL of deionized water. Place the solution in a constant 55°C water bath and stir continuously with a magnetic force for at least 1 h to ensure that the sodium alginate is completely dissolved, forming a 1.0% sodium alginate solution.

[0044] S8. Weigh 0.25 g of chitosan solid powder and dissolve it in 45 mL of deionized water. Place the solution in a constant 50°C water bath, add 5 mL of 2.0% glacial acetic acid solution, and continuously stir magnetically for at least 1 h to ensure complete dissolution of the chitosan, forming a 0.5% chitosan solution.

[0045] S9. Mix 10 mL of the jellyfish polysaccharide solution obtained in step S6 with 10 mL of the sodium alginate solution obtained in step S7 to form a mixed solution of jellyfish polysaccharide and sodium alginate.

[0046] S10. The mixed solution obtained in step S9 is slowly and evenly added dropwise to a 20 mL chitosan solution obtained in step S8 using a 5 mL syringe. The mixture is continuously stirred at 1200 r / min during the addition process.

[0047] S11. Slowly add 10 mL of 0.3% calcium chloride solution to the above mixture and continue stirring for 1 hour.

[0048] S12. After the above solution is allowed to stand for 1 hour to complete solidification, it is filtered and then repeatedly rinsed with deionized water. After freeze-drying, jellyfish polysaccharide-sodium alginate-chitosan ternary composite gel particles with qualified purity can be obtained.

[0049] S13. The average particle size of the above particles is approximately 3.0 mm, and they are labeled as composite hydrogel particles (JSP / SA / CS).

[0050] The composite hydrogel particles (JSP / SA / CS) obtained above were characterized. The hydrogel particles in Example 1 were rapidly frozen with liquid nitrogen, freeze-dried to make the cross-section smooth, and then sputter-coated with gold using a gold sputtering machine. The surface morphology of the cross-section was observed using a field emission scanning electron microscope (FE-SEM, JSM-IT800, NEC, Japan) at an accelerating voltage of 20 kV. Figure 4 , 5 As shown. By Figure 4 , 5 As can be seen, the hydrogel exhibits a highly regular gradient porous structure with obvious radial stratification. From the edge to the center, the pore morphology gradually changes in a regular pattern: the outer layer is a macroporous region (100–300 μm), with a honeycomb / capsule structure, forming rapid mass transfer channels; it transitions inward to a mesoporous buffer layer; and the central region is a dense network structure (10–50 μm), with significantly reduced pore size and uniform distribution. This hierarchical pore design achieves a significant increase in specific surface area. In terms of pore wall characteristics, the ternary system exhibits a moderate thickness (10–15 μm) and uniform distribution, with a rough fibrous network morphology on the surface. This structure originates from the intercalation and reinforcement effect of the rigid segments of jellyfish polysaccharide (JSP) on the sodium alginate-chitosan matrix, forming a complex composite framework that effectively improves the mechanical support performance and structural stability of the material. Figure 8 This is a comparison image of the composite hydrogel particles (JSP / SA / CS) before and after freeze-drying.

[0051] At room temperature, Fourier transform infrared spectroscopy (Thermo-Nicolet, Nicolet iS10) was used to compare and analyze the active groups that may exist on the surface of the lyophilized gel particles of Example 1. The potassium bromide pellet method was used for measurement, with 64 scans and a resolution of 2 cm⁻¹. -1 Wavenumber variation range 4000~400 cm -1 .like Figure 3 As shown, JSP retains its characteristic sulfate group absorption peak (1240.9 cm⁻¹) in the composite system. -1 Meanwhile, its hydroxyl stretching vibration peak decreased from 3274.5 cm⁻¹. -1 Displaced to 3281.8 cm -1 This indicates that the hydroxyl groups of JSP participate in the reconstruction of the hydrogen bond network with the SA / CS molecular chains; furthermore, the JSP / SA / CS ternary composite system at 1731.9 cm⁻¹... -1 A new absorption peak belonging to the protonated carboxyl group appears at 1598.1 cm⁻¹. -1 The peak at this point is characteristic of the carboxylate group resulting from the electrostatic recombination of SA and CS, while the original amide II band of JSP (1531.4 cm⁻¹) is present. -1The disappearance of the CS amino group confirms that the amino group of CS has been fully protonated and formed a polyelectrolyte complex with SA. The above spectroscopic evidence together indicate that JSP has been successfully embedded in the SA / CS ion coordination-electrostatic complex dual network structure.

[0052] Example 2 The only difference from Example 1 is: In step S6, 0.1 g of lyophilized jellyfish polysaccharide powder was added to 50 mL of deionized water to form a 0.2% jellyfish polysaccharide solution; in step S7, 0.1 g of sodium alginate solid powder was dissolved in 50 mL of deionized water to form a 0.2% sodium alginate solution. The remaining steps were the same as in Example 1.

[0053] Example 3 The only difference from Example 1 is: In step S6, 0.25 g of lyophilized jellyfish polysaccharide powder was added to 50 mL of deionized water to form a 0.5% jellyfish polysaccharide solution; in step S7, 0.25 g of sodium alginate solid powder was dissolved in 50 mL of deionized water to form a 0.5% sodium alginate solution. The remaining steps were the same as in Example 1.

[0054] Comparative Example 1 A method for preparing chitosan and sodium alginate gel particles is as follows: S1. Weigh 0.25 g of sodium alginate solid powder and dissolve it in 50 mL of deionized water.

[0055] S2. Place the above solution in a constant 55°C water bath and stir continuously with magnetic force for at least 1 hour to ensure that the sodium alginate is completely dissolved, forming a sodium alginate solution with a mass fraction of 0.5%.

[0056] S3. Weigh 0.25 g of chitosan solid powder and dissolve it in 45 mL of deionized water.

[0057] S4. Place the solution from step S3 above under constant 50°C water bath conditions, add 5 mL of 2.0% glacial acetic acid solution, and continuously stir magnetically for at least 1 h to ensure complete dissolution of chitosan, forming a 0.5% chitosan solution.

[0058] S5. Slowly and evenly add 10 mL of the sodium alginate solution obtained in step S2 to a 5 mL syringe containing 20 mL of the chitosan solution obtained in step S4. Stir continuously at 1200 r / min during the addition process.

[0059] S6. Slowly add 10 mL of 0.3% calcium chloride solution to the above mixture and continue stirring for 2 h.

[0060] S7. After the above solution is allowed to stand for 1 hour to complete solidification, it is filtered and then repeatedly rinsed with deionized water. After freeze-drying, chitosan-sodium alginate composite gel particles with qualified purity are obtained.

[0061] The average particle size of the above particles is about 2.5 mm, and they are labeled as hydrogel particles (SA / CS).

[0062] The composite hydrogel particles (SA / CS) obtained above were characterized.

[0063] The hydrogel particles in Comparative Example 1 were rapidly frozen in liquid nitrogen, freeze-dried to make the cross-section smooth, and then sputter-coated with gold using a gold sputtering machine. The surface morphology of the cross-section was observed using a field emission scanning electron microscope (FE-SEM, JSM-IT800, NEC, Japan) at an accelerating voltage of 20 kV. Figure 6 , 7 As shown. By Figure 6 , 7 As can be seen, the hydrogel structure is relatively simple, exhibiting a uniform honeycomb porous structure with a fairly even distribution of pores, but lacking a gradient hierarchy. The pore walls are smooth, thin sheets (3–8 μm) and are prone to buckling deformation under stress, resulting in insufficient structural rigidity. The pore size difference between the inner and outer layers is small (100–300 μm), failing to form an effective hierarchical mass transfer network, thus limiting the specific surface area and the exposure of active sites. Figure 9 This is a comparison image of the composite hydrogel particles (SA / CS) before and after freeze-drying.

[0064] The adsorption effects of the jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel particles obtained in the above examples and the sodium alginate-chitosan binary composite hydrogel particles obtained in Comparative Example 1 were measured. To verify the broad-spectrum adsorption performance and structural stability of the jellyfish polysaccharide-sodium alginate-chitosan composite gel particles (JSP / SA / CS group) prepared in Example 1 of this invention, this study selected neutral antibiotic (chloramphenicol CAP) and high-turbidity actual aquaculture wastewater (suspended pollutants) for comparative adsorption experiments.

[0065] (1) Construction of the chloramphenicol standard curve Chloramphenicol solutions with concentrations of 1, 2, 4, 8, and 16 μg / mL were prepared. The absorbance at 279 nm was measured using a UV spectrophotometer. A standard curve was plotted with chloramphenicol concentration on the x-axis and absorbance on the y-axis.

[0066] (2) Determination of the adsorption and removal rate of chloramphenicol in water 49.5 mL of ultrapure water and 0.5 mL of chloramphenicol stock solution were respectively placed into 50 mL centrifuge tubes (numbered 1, 2, and 3). Then, 200 mg of hydrogel microspheres from different components in Example 1 and Comparative Example 1 were added to each tube. Centrifuge tube number 1 served as a blank control, without the addition of hydrogel microspheres. The centrifuge tube was wrapped in aluminum foil and placed in a constant-temperature shaker at 25°C, 150 r / min, and pH 6.6–7.0 for adsorption. At predetermined time intervals (0, 2, 4, 6, 8, 16, and 24 h), 3 mL samples were taken, and the absorbance of chloramphenicol (CAP) in the filtrate at 279 nm was measured using a UV-Vis spectrophotometer. The corresponding concentration was calculated based on the standard curve described above. The adsorption removal rate (P, %) of CAP was calculated using the following formula: In the formula: C0 is the initial concentration of CAP (mg·L) -1 ); C e CAP equilibrium concentration (mg·L) -1 P represents the adsorption removal rate (%).

[0067] like Figure 1 As shown, with 24 h as the final adsorption equilibrium point, when removing neutral small molecule chloramphenicol, the hydrogel particles in Example 1 and Comparative Example 1 showed no statistically significant difference in the ternary particles (32.22%) of the present invention compared with the traditional binary SA / CS particles (30.94%), but compared with the untreated blank group, both maintained a high adsorption level range of 30%~32%.

[0068] (3) Adsorption analysis of actual water bodies with high turbidity The collected aquaculture wastewater was filtered through a 300-mesh sieve and then aliquoted into centrifuge tubes, 50 mL per tube. 200 mg of hydrogel microspheres containing different components from Example 1 and Comparative Example 1 were added to each tube. The centrifuge tubes were placed in a constant-temperature shaker and subjected to adsorption at 25°C, 150 r / min, and pH 6.6–7.0. Samples were taken at preset time points (0, 1, 2, 3, 4, 12, and 24 h), and the absorbance of the supernatant at 600 nm (initial absorbance 0.178–0.182) was measured. The rate of change of absorbance at different adsorption times was calculated to evaluate the removal effect of the microspheres on water turbidity.

[0069] like Figure 2 As shown, under the actual background of extremely high natural sedimentation in aquaculture wastewater, the hydrogel particles in Example 1 and Comparative Example 1 have drastically different purification effects on aquaculture wastewater. In complex real-world wastewater, using 24 hours as a control point, traditional sodium alginate-chitosan binary composite particles, unable to resist interference from complex background ions, undergo structural swelling and dissociation, resulting in more turbid water after treatment compared to the control group. For example, the removal rate of the (SA / CS) group was lower than that of the control group at 24 hours. The ternary particles of this invention break through the natural sedimentation baseline, and the suspended solids removal effect is significantly better than that of Comparative Example 1, making it an ideal material for achieving deep water purification.

[0070] This demonstrates that the jellyfish polysaccharide-sodium alginate-chitosan composite gel particles prepared in the examples exhibit excellent physical size stability in harsh water conditions due to their dual "ion coordination-electrostatic composite" network. Simultaneously, the jellyfish polysaccharide molecular chains endow the particles with superior trapping and bridging flocculation functions, firmly capturing tiny colloids that are difficult to settle naturally, thus achieving deep purification of actual wastewater.

[0071] The above embodiments represent only some preferred implementations of the present invention and are intended to illustrate the technical content of the present invention, rather than to limit the scope of protection of the present invention. All changes, substitutions, or modifications made by those skilled in the art to existing technical solutions without departing from the essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel, characterized in that, The composite hydrogel is a ternary composite hydrogel obtained by self-assembly of jellyfish polysaccharide solution, sodium alginate solution and chitosan acidic solution through coordination crosslinking; wherein, in the hydrogel system, jellyfish polysaccharide solution and sodium alginate solution are mixed in equal volumes, and the final mass fraction of chitosan acidic solution in the system is 0.1%~1.0%.

2. The jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel according to claim 1, characterized in that, Jellyfish polysaccharide solution was mixed with sodium alginate solution, and then the mixture was dropped into an acidic chitosan solution. The mixture was stirred continuously at room temperature and self-assembled to form a spherical precursor. Then, calcium ion coordination solidification was used to obtain jellyfish polysaccharide-sodium alginate-chitosan composite gel particles.

3. The jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel according to claim 1 or 2, characterized in that, The jellyfish polysaccharide solution was obtained by desalting and temperature-controlled enzymatic hydrolysis purification. The acidic chitosan solution is prepared by adding chitosan solid powder to deionized water, then adding organic acid and stirring continuously until completely dissolved.

4. The jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel according to claim 3, characterized in that, The jellyfish polysaccharide solution is 1) Take sand jellyfish ( Nemopilema nomurai The umbrella cap is repeatedly soaked and washed with deionized water until desalted. Deionized water is added at a ratio of 1 to 3:1 (liquid to material) and homogenized in an ice bath at high speed until it becomes a paste. 2) Adjust the pH of the above homogenate to 6.0~7.0 using a 0.5 mol / L acetic acid-sodium acetate solution; 3) Add 1000~3000 U / g neutral protease to the above homogenate for enzymatic hydrolysis, and then place it in a 95~100℃ water bath for 10~15 min to inactivate it. 4) After inactivating the above enzyme hydrolysate, centrifuge at 8000~10000 r / min to remove impurities, and concentrate the supernatant under reduced pressure to 1 / 4~1 / 3 of the original volume; then add ethanol and centrifuge to collect the precipitate. 5) After redissolving the above precipitate, it was placed in a dialysis bag with a molecular weight cutoff of 8000~14000 Da and dialyzed at 4℃ for 48~72 h. Finally, it was pre-frozen at -80℃ and freeze-dried under vacuum to obtain high-purity jellyfish polysaccharide freeze-dried powder; the dry powder was resuspended in water.

5. The jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel according to claim 3, characterized in that, In step 3), add 1000~3000 U / g of neutral protease according to the wet weight of the jellyfish cap, and hydrolyze by shaking at 40~50℃ for 3~5 h.

6. The jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel according to claim 3, characterized in that, In step 4), anhydrous ethanol pre-cooled to 4°C is slowly added dropwise to the concentrated product, and then the product is allowed to stand and age at 4°C for 12-24 hours; wherein the volume of anhydrous ethanol pre-cooled to 4°C added is 3-5 times the volume of the concentrated liquid.

7. A method for preparing the jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel according to claim 1, characterized in that, Jellyfish polysaccharide solution was mixed with sodium alginate solution, and then the mixture was dropped into an acidic chitosan solution. The mixture was stirred continuously at room temperature and self-assembled to form a spherical precursor. Then, calcium ion coordination solidification was used to obtain jellyfish polysaccharide-sodium alginate-chitosan composite gel particles.

8. The method for preparing the jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel according to claim 7, characterized in that, 1) Mix the jellyfish polysaccharide solution with the sodium alginate solution at a volume ratio of 1:1 to obtain the jellyfish polysaccharide-sodium alginate mixture; 2) The mixture is added dropwise to the chitosan acidic solution, and under stirring conditions, the polyelectrolyte self-assembles to form a primary jellyfish polysaccharide-sodium alginate-chitosan composite gel particle suspension. 3) Add calcium chloride solution to the suspension for coordination crosslinking, and then prepare ternary composite hydrogel particles by static curing, separation and washing.

9. The method for preparing the jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel according to claim 8, characterized in that, After adding calcium chloride solution in step 3), continue stirring for 0.5 to 1.5 h, and then let it stand and solidify for 0.5 to 3.0 h. The ternary composite hydrogel particles with an average particle size of 2.0 to 4.0 mm are obtained by separation and washing.

10. An application of the jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel according to claim 1, characterized in that, The application of the jellyfish polysaccharide-sodium alginate-chitosan composite hydrogel as an adsorbent in the field of water treatment.

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