Green preparation method of sodium alginate / casein gel beads based on Maillard reaction
Sodium alginate/casein gel beads were prepared by Maillard reaction and microwave heating, which solved the problem of low removal efficiency of stubborn dyes in industrial wastewater and achieved a highly efficient and environmentally friendly dye adsorption effect.
Patent Information
- Application Number
- CN202511403100.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-29
- Publication Date
- 2026-02-10
AI Technical Summary
Existing technologies are ineffective at removing stubborn dyes from industrial wastewater, and traditional adsorption materials suffer from low efficiency and environmental incompatibility.
Sodium alginate/casein gel beads were prepared using the Maillard reaction. The glycosylation reaction of casein and sodium alginate was promoted by microwave heating to form highly stable gel beads for dye adsorption.
The prepared gel beads have high stability and high adsorption efficiency, can effectively remove dyes, and have good biocompatibility and can be reused.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of dye adsorption gel bead preparation technology, specifically relating to a green preparation method of sodium alginate / casein gel beads based on Maillard reaction. Background Technology
[0002] Rapid industrial development has led to societal progress in many ways. However, industrial wastewater generated by industrial processes disrupts ecological balance, pollutes water bodies, alters water ion balance, and threatens human and other life. Toxic and persistent dyes discharged into water bodies reduce biodiversity in aquatic ecosystems. They can also bioaccumulate through the food chain, potentially endangering human health. In recent years, adsorption methods utilizing biomaterials, mineral oxides, activated carbon, or polymer resins have been proposed. Various unconventional adsorption materials have been investigated to elucidate their dye removal capabilities. For industrial acceptance, adsorbents must demonstrate efficiency, environmental compatibility, and sufficient availability. Sodium alginate / casein meets most of these characteristics and is used as a gel in various fields of adsorption science.
[0003] Casein (CA) makes up about 80% of the total protein in milk. It is an important source of calcium and phosphorus and contains all the essential amino acids for the human body. CA contains four phosphorylated proteins (…). α -s1-、 α -s2-、 β -and κ CNs), which exist in bovine genetic and post-translational modified variants. As a well-known biopolymer, CA is non-toxic and biodegradable. It contains many hydrophilic functional groups, exhibiting good surface activity and stability, making it suitable for preparing hydrogels, and is readily available and relatively economical. Sodium alginate (SA) is a widely used biomass material, considered an excellent substrate for preparing adsorbents due to its high biocompatibility, biodegradability, and renewability. It is a linear anionic copolymer with (1-4) linkages. β -D-mannuronate (M) and C-5 epimer α Homopolymer blocks of L-heptaurinate (G) residues are covalently linked together in various sequences or blocks. It has been reported that the carboxyl group of SA and the oxygen atom of pyranose can form stable pentagonal chelates with metal ions, thus providing binding sites for the adsorption process.
[0004] The Maillard reaction is essentially the covalent bonding of free amino acid groups in proteins and carbonyl groups of reducing sugars under heating conditions, forming Schiff bases and further amadori compounds. Numerous studies have shown that protein-sugar covalent coupling effectively improves solubility, emulsification, and foaming properties compared to pure proteins. Unlike monosaccharides or disaccharides, the covalent bonding of polysaccharides to proteins has a greater advantage in enhancing specific physicochemical properties.
[0005] In this study, SA hydrogels were modified using microwave heating to remove dyes (MB) from wastewater using a glycosylation reaction (also known as the Maillard reaction) between CA and calcium alginate in CA. Summary of the Invention
[0006] To address the problems of existing technologies, the present invention aims to provide a green preparation method for sodium alginate / casein gel beads based on the Maillard reaction. The SA / CA gel beads prepared by the present invention have high stability, high adsorption efficiency, high biocompatibility and high reusability, and achieve adsorption of methylene blue dye at room temperature.
[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a green preparation method for sodium alginate / casein gel beads based on the Maillard reaction, comprising the following steps: (1) 2% wt casein solution, adjust pH to 12 with 1 mol / L NaOH, stir at 50°C for 30 min until fully dissolved.
[0008] (2) Take 50 mL of the above solution, add 1 g of sodium alginate, stir for 30 min until completely dissolved and free of bubbles.
[0009] (3) Place it in a 100 mL round-bottom flask, microwave at 50 W for 20 min, cool to room temperature, and add 0.5 g of sodium alginate to dissolve completely.
[0010] (4) Take another 5 wt% CaCl2 solution in a beaker and add it dropwise at a rate of 0.2 ml using a peristaltic pump until all the gel beads settle to the bottom. The preparation is then complete.
[0011] In the above technical solution, the volume of the casein solution in step (1) is 50 mL.
[0012] In the above technical solution, the mass ratio of sodium alginate to casein in step (2) is 1:1. In the above technical solution, it takes at least 18 hours for sodium alginate to be completely dissolved without bubbles in step (2).
[0013] In the above technical solution, adding 0.5 g of sodium alginate in step (3) is mainly to promote the formation of gel beads. In the above technical solution, at least 20 mL of calcium chloride solution is required in step (4).
[0014] In the above technical solution, the preparation in step (4) requires washing with ultrapure water three times.
[0015] A sodium alginate / casein gel bead based on the Maillard reaction, prepared using the above method, has a diameter of approximately 3 mm. THAT The value was 908 mg / g when adsorption equilibrium was reached.
[0016] This invention provides a green preparation method for sodium alginate / casein gel beads based on the Maillard reaction. Different configurations of casein and sodium alginate are grafted via a Maillard reaction through microwave heating, enhancing the stability and adsorption sites of the gel beads. Microwave heating is a common green chemical reaction method, which can effectively reduce potential energy / material waste during synthesis. This gel material can achieve high-efficiency adsorption of cationic dyes in an aqueous environment, showing promising application prospects.
[0017] Compared with existing technologies, the beneficial effects of this invention are: casein and sodium alginate are linked by amide bonds, which enhances the adsorption capacity and stability of this gel material. The gel material prepared by this invention has a simple process, good stability and biocompatibility, and can be applied to the treatment of water pollution. Detailed Implementation
[0018] The technical solution of the present invention will be further described in detail below with reference to specific embodiments: Example 1: A green preparation method for sodium alginate / casein gel beads based on the Maillard reaction includes the following steps: (1) To prepare a 2 wt.% CA solution, add 1 g casein and 50 mL to a beaker, and then adjust the pH to 12 with 1 M NaOH solution. Stir the solution at 50 °C for 30 minutes until completely dissolved.
[0019] (2) Then, take 50 mL of the above solution and add 1.0 g of SA (1:1). Stir the mixture for 30 minutes until it is completely dissolved and there are no bubbles left (it takes about 18 hours for the bubbles to disappear).
[0020] (3) Place the solution in a 100 mL round-bottom flask. Heat in a 50 W microwave oven for 20 minutes, cool to room temperature, and then add 0.5 g SA to complete the shape of the gel beads.
[0021] (4) Take another 20 mL of 5 wt.% CaCl2 solution into a beaker and add it using a peristaltic pump at a rate of 0.2 mL per drop. After crosslinking for 6 hours, wash three times with ultrapure water.
[0022] Example 2: A green preparation method for sodium alginate / casein gel beads based on the Maillard reaction includes the following steps: (1) To prepare a 3 wt.% CA solution, add 1.5 g casein and 50 mL to a beaker, and then adjust the pH to 12 with 1M NaOH solution. Stir the solution at 50 °C for 30 minutes until completely dissolved.
[0023] (2) Then, take 50 mL of the above solution and add 1.0 g of SA (3:2). Stir the mixture for 30 minutes until completely dissolved. It is clear and there are no air bubbles left (it takes about 18 hours for the air bubbles to be gone).
[0024] (3) Place the solution in a 100 mL round-bottom flask. Heat in a 50 W microwave oven for 20 minutes, cool to room temperature, and then add 0.5 g SA to complete the shape of the gel beads.
[0025] (4) Take another 20 mL of 5 wt.% CaCl2 solution into a beaker and add it using a peristaltic pump at a rate of 0.2 mL per drop. After crosslinking for 6 hours, wash three times with ultrapure water.
[0026] Example 3: A green preparation method for sodium alginate / casein gel beads based on the Maillard reaction includes the following steps: (1) To prepare a 2 wt.% CA solution, add 1 g casein and 50 mL to a beaker, and then adjust the pH to 12 with 1 M NaOH solution. Stir the solution at 50 °C for 30 minutes until completely dissolved.
[0027] (2) Then, take 50 mL of the above solution and add 1.5 g of SA (2:3). Stir the mixture for 30 minutes until it is completely dissolved and there are no bubbles left (it takes about 18 hours for the bubbles to disappear).
[0028] (3) Place the solution in a 100 mL round-bottom flask. Heat in a 50 W microwave oven for 20 minutes, cool to room temperature, and then add 0.5 g SA to complete the shape of the gel beads.
[0029] (4) Take another 20 mL of 5 wt.% CaCl2 solution into a beaker and add it using a peristaltic pump at a rate of 0.2 mL per drop. After crosslinking for 6 hours, wash three times with ultrapure water.
[0030] Example 4: Determination of Adsorption Value of Gel Material Using MB as a typical pollutant, a systematic adsorption experiment was conducted to investigate the adsorption capacity of SA / CA hydrogel as a dye adsorbent. Adsorption experiments were performed at 300 K (27 °C) to simulate near-room temperature (25 °C) and achieve visual cleanliness, which is relevant to potential biomedical or environmental applications. SA / CA hydrogel (0.5 g / L) was added to a beaker containing MB solution (300 mg / L, 50 mL) as the adsorbent, and adsorption was carried out at 300 K with an oscillation rate of 120 r / min for 1440 min. After adsorption, the supernatant in the beaker was collected, and the absorbance of MB before and after adsorption was measured using a UV spectrophotometer to calculate the adsorption value. For MB solutions with an initial concentration exceeding 10 mg / L, the supernatant was appropriately diluted to ensure that the absorbance value fell within the calibration range (0–10 mg / L).
[0031] The adsorption value of SA / CA gel beads was measured using a UV spectrophotometer. Methylene blue aqueous solutions with concentrations of 2 to 10 mg / L were taken, and the absorbance of the corresponding concentrations was measured at 665 nm. The absorbance was linearly fitted to the concentration of methylene blue to establish a regression equation.
[0032] Adsorption value ( THAT = (MB concentration before adsorption - MB concentration after adsorption) × solution volume / mass of gel material. The average adsorption value of the SA / CA gel beads obtained in Case 1-3 is 270 mg / g ~ 310 mg / g.
[0033] In Examples 1-3, SA / CA gel beads were used under the conditions of pH = 7 and T = 27°C. THAT The values of 277.52 ± 0.96 mg / g, 305.01 ± 0.22 mg / g, and 275.57 ± 1.75 mg / g, respectively, indicate that the gel material has high MB adsorption performance.
Claims
1. A green preparation method for sodium alginate / casein gel beads based on the Maillard reaction, characterized in that, The preparation method comprises the following steps: (1) 2% wt casein solution, adjust pH to 12 with 1 mol / L NaOH, stir at 50 °C for 30 min until fully dissolved; (2) Take 50 mL of the above solution, add 1 g of sodium alginate, stir for 30 min until completely dissolved and free of bubbles; (3) Place it in a 100 mL round-bottom flask, microwave at 50 W for 20 min, cool to room temperature, and add 0.5 g sodium alginate to dissolve completely; (4) Take another 5 wt% CaCl2 solution in a beaker and add it dropwise at a rate of 0.2 ml per drop using a peristaltic pump until all the gel beads settle to the bottom. The preparation is then complete.
2. The green preparation method of sodium alginate / casein gel beads based on Maillard reaction according to claim 1, characterized in that, The volume of the casein solution in step (1) is 50 mL.
3. The green preparation method of sodium alginate / casein gel beads based on Maillard reaction according to claim 1, characterized in that, In step (2), the mass ratio of sodium alginate to casein is 1:
1.
4. The green preparation method of sodium alginate / casein gel beads based on Maillard reaction according to claim 1, characterized in that, In step (2), sodium alginate needs to be completely dissolved without bubbles for at least 18 hours.
5. The green preparation method of sodium alginate / casein gel beads based on Maillard reaction according to claim 1, characterized in that, The addition of 0.5 g sodium alginate in step (3) is mainly to promote the formation of gel beads.
6. The green preparation method of sodium alginate / casein gel beads based on Maillard reaction according to claim 1, characterized in that, In step (4), at least 20 mL of calcium chloride solution is required.
7. The green preparation method of sodium alginate / casein gel beads based on Maillard reaction according to claim 1, characterized in that, In step (4), the preparation is completed and the product needs to be washed three times with ultrapure water.
8. The sodium alginate / casein gel beads prepared by the preparation method according to any one of claims 1-7, characterized in that, The prepared sodium alginate / casein gel beads have a diameter of approximately 3 mm.
9. The sodium alginate / casein gel beads prepared by the preparation method according to any one of claims 1-7, characterized in that, q e The value was 908 mg / g when adsorption equilibrium was reached.