Preparation method and application method of a biomacromolecule chitosan modified magnetic sepiolite adsorbent
By preparing a biopolymer chitosan-modified magnetic sepiolite adsorbent, the complex preparation and high cost of removing antimony from water in existing technologies have been solved, realizing efficient, economical, and environmentally friendly antimony ion adsorption and regeneration recycling, which is suitable for the treatment of heavy metal pollution in water environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIANGTAN UNIV
- Filing Date
- 2026-04-08
- Publication Date
- 2026-06-02
AI Technical Summary
Existing methods for removing trivalent and pentavalent antimony from water using adsorption materials suffer from complex preparation processes, high costs, and potential secondary pollution risks. Furthermore, their recyclability and reusability are insufficient, making it difficult to achieve efficient, economical, and environmentally friendly simultaneous removal.
The magnetic sepiolite adsorbent is modified by using the biopolymer chitosan. By loading a large amount of chitosan onto the surface of magnetic sepiolite and modifying it with the crosslinking agent glutaraldehyde, the preparation process is simple and low-cost. The material has strong mechanical and chemical strength and can be quickly recycled and regenerated under an external magnetic field.
It achieves high adsorption capacity for antimony ions and excellent recyclability, reducing production costs and environmental burden. The adsorbent has high removal efficiency for trivalent and pentavalent antimony and complies with the principle of environmental sustainability.
Smart Images
Figure CN122124754A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of adsorbent technology, and in particular to a method for preparing and applying a biopolymer chitosan-modified magnetic sepiolite adsorbent. Background Technology
[0002] With the accelerating pace of global industrialization and the booming development of modern manufacturing, heavy metal and metalloid pollution in the aquatic environment has become a major problem threatening global ecosystem security and human health. Among the many pollutants, antimony (Sb) is a typical toxic metalloid element. The International Agency for Research on Cancer (IARC) has identified antimony as one of the compounds that pose a carcinogenic risk to humans.
[0003] Antimony primarily exists in trivalent and pentavalent states, and due to the complexity of water bodies, Sb(III) and Sb(V) can coexist in water. They typically exist as complexes or coordination compounds, and their forms in water vary depending on pH. Therefore, developing methods for the simultaneous and efficient removal of trivalent and pentavalent antimony is of great significance. Among the many methods for antimony removal, adsorption is widely popular due to its cost-effectiveness, high efficiency, and recyclability. In recent years, many newly synthesized adsorbent materials have exhibited excellent adsorption performance for antimony, such as metal and oxide-based materials, carbon-based materials, metal-organic frameworks (MOFs), and layered double hydroxides. However, complex preparation processes, high costs, and potential secondary pollution risks have significantly limited the practical application of these materials. Based on this, researchers have gradually turned their attention to widely available natural substances. These materials have the advantages of low cost, abundant sources, and renewability, perfectly aligning with the core requirements of sustainable development strategies.
[0004] Sepiol is a natural, abundant, and eco-friendly fibrous porous clay mineral with a large specific surface area, high porosity, and a loose, unique pore structure. The surface of sepiol contains numerous silanol groups, facilitating chemical modification and making it an ideal adsorption carrier. Chitosan (CTS) is a commonly used biopolymer with good biocompatibility, chemical stability, non-toxicity, biodegradability, and chelating properties. Studies have shown that loading chitosan onto the surface of biochar can improve the adsorption capacity of the composite material for antimony. However, the adsorption capacity of current materials still has significant room for improvement, and the ease of recyclability and reusability of the adsorbent have a decisive impact on its techno-economic and environmental sustainability. Therefore, developing a novel, efficient, economical, environmentally friendly, and easily scalable magnetic adsorbent has significant scientific research value and engineering application prospects. This adsorbent uses widely available and inexpensive raw materials, sepiol and chitosan, and utilizes a cross-linking agent to load a large amount of chitosan onto the surface of magnetic sepiol. The synthesis process is efficient and simple, avoiding complex steps and the use of toxic solvents, significantly reducing production costs and environmental burden. Summary of the Invention
[0005] In view of this, the present invention provides a biopolymer chitosan-modified magnetic sepiolite adsorbent, its preparation method, and its application method. The adsorbent prepared by this method has excellent adsorption performance for antimony ions, and also has significant cost-effectiveness. Moreover, the material synthesis and application process comply with the principle of environmental sustainability, does not generate secondary pollution, and the adsorbent can be quickly recycled and regenerated under the action of an external magnetic field, thus having good recycling capacity.
[0006] A method for preparing a biopolymer chitosan-modified magnetic sepiolite adsorbent, the method comprising:
[0007] S1. Place the sepiolite in a tube furnace protected by N2 and calcine it;
[0008] S2. Ferric chloride hexahydrate and ferrous sulfate heptahydrate were mixed with sepiolite in deionized water, and magnetic sepiolite was obtained by co-precipitation.
[0009] S3. Add magnetic sepiolite to chitosan solution and mix and crosslink at 85 °C for 20 h to obtain adsorbent.
[0010] Preferably, step S1 specifically involves placing sepiolite in a tube furnace under N2 protection and calcining it at 230 °C for 3 h.
[0011] Preferably, step S2 specifically involves: mixing 2.3246 g of ferric chloride hexahydrate and 1.1954 g of ferrous sulfate heptahydrate in deionized water and ultrasonically dispersing for 30 min; then adding 2 g of sepiolite; stirring at room temperature for 1 h; adding concentrated ammonia dropwise to adjust the pH to 10; heating in a constant temperature water bath to 70 °C; and continuing to stir for 1 h; aging at 60 °C for 1 h; and washing with deionized water until the supernatant is colorless to obtain magnetic sepiolite.
[0012] Preferably, after step S2, the method further includes: washing the magnetic sepiolite with deionized water until the supernatant is colorless, separating the solid and drying it in a vacuum drying oven at 60 °C for 12 h.
[0013] Preferably, step S3 specifically involves: dissolving 0.5 g of chitosan in 60 mL of 2.5% acetic acid solution, dispersing the washed magnetic sepiolite in the above solution, stirring at room temperature for 60 min, adding 2 mL of 25% glutaraldehyde solution, and then mixing the mixed solution at 85 °C for 20 h.
[0014] Preferably, after step S2, the method further includes: dispersing the obtained material in 100 mL of 1% sodium hydroxide, stirring at room temperature for 1-2 h, washing with water until the supernatant is colorless, drying and grinding under vacuum at 60 °C.
[0015] Preferably, according to the preparation method of claim 1, the magnetic sepiolite with a mass ratio of Fe3O4 to sepiolite of 1:2 is obtained.
[0016] A biopolymer chitosan-modified magnetic sepiolite adsorbent, wherein the adsorbent is prepared by the above method.
[0017] A method for applying a biopolymer chitosan-modified magnetic sepiolite adsorbent, the method comprising:
[0018] The adsorbent is added to the wastewater containing heavy metal ions for adsorption, and then the solid and liquid are separated after adsorption.
[0019] This invention provides a biopolymer chitosan-modified magnetic sepiolite adsorbent, its preparation method, and its application method. This method modifies magnetic sepiolite with chitosan under the action of the crosslinking agent glutaraldehyde. The modification conditions are simple, the preparation process is not complicated, the yield is high, and the cost is low. Furthermore, the prepared adsorbent not only possesses strong mechanical and chemical strength, uniformly distributed pore size, and environmental friendliness, but also exhibits good magnetic separation characteristics, large adsorption capacity, and excellent recyclability, with high antimony ion removal efficiency. Attached Figure Description
[0020] Figure 1This is a schematic diagram of the preparation process of a biopolymer chitosan-modified magnetic sepiolite adsorbent according to the present invention.
[0021] Figure 2 The adsorption capacity curves of antimony for the chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1 at different pH values are shown.
[0022] Figure 3 This is a time curve of antimony adsorption by the chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1.
[0023] Figure 4 The adsorption capacity diagrams for antimony of the sepiolite, magnetic sepiolite, and chitosan-modified magnetic sepiolite adsorbents prepared in Specific Example 1 are shown.
[0024] Figure 5 This is a graph showing the adsorption capacity of chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1, which simultaneously adsorbs antimony in two valence states.
[0025] Figure 6 This is a diagram illustrating the recycling of chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1.
[0026] Figure 7 The image shows the TEM test results of the chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1.
[0027] Figure 8 The image shows the infrared spectra of the chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1 before and after adsorbing antimony ions. Detailed Implementation Plan
[0028] The technical solutions of the present invention will be clearly and completely described below with reference to 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 are within the scope of protection of the present invention.
[0029] It should be understood that, as used in this specification and the accompanying requirements, the terms “comprising” and “including” indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements and / or components.
[0030] It should also be further understood that the term "and / or" as used in this specification refers to any combination of one or more of the items listed above, as well as all possible combinations, and includes such combinations. Specific Implementation Example 1
[0032] A method for preparing a biopolymer chitosan-modified magnetic sepiolite adsorbent, the method comprising:
[0033] (1) Place sepiolite in a tube furnace under N2 protection and calcine at 230 °C for 3 h.
[0034] (2) Mix 2.3246 g of ferric chloride hexahydrate and 1.1954 g of ferrous sulfate heptahydrate in deionized water and ultrasonically disperse for 30 min. Then add 2 g of sepiolite and stir at room temperature for 1 h. Add concentrated ammonia dropwise to adjust the pH to 10. Heat the mixture in a constant temperature water bath to 70 ℃ and continue stirring for 1 h. After aging at 60 ℃ for 1 h, wash with deionized water until the supernatant is colorless to obtain magnetic sepiolite.
[0035] (3) Dissolve 0.5 g of chitosan in 60 mL of 2.5% acetic acid solution, disperse the washed magnetic sepiolite in the above solution, stir at room temperature for 60 min, add 2 mL of 25% glutaraldehyde solution, and then mix the mixed solution at 85 ℃ for 20 h. Disperse the obtained material in 100 mL of 1% sodium hydroxide, stir at room temperature for 1-2 h, wash with water until the supernatant is colorless, dry and grind under vacuum at 60 ℃ to obtain chitosan-modified magnetic sepiolite adsorbent, namely MSep@CTS. Specific Implementation Example 2
[0037] The chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1 was applied, and the removal rate of antimony by the adsorbent under different pH conditions was determined. The application method is as follows:
[0038] Accurately transfer 100 mL of Sb(III) and Sb(V) solutions with an initial concentration of 100 mg / L into 250 mL Erlenmeyer flasks. Adjust the pH of the solutions to 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 respectively using dilute hydrochloric acid or dilute sodium hydroxide solution. Add 20 mg of the chitosan-modified magnetic sepiolite adsorbent (MSep@CTS) prepared in Example 1 to each Erlenmeyer flask. React in a 25 ℃ air bath shaker for 24 h. Measure the antimony ion concentration before and after the reaction to obtain the antimony adsorption capacity of the adsorbent under different pH conditions. Figure 2 As shown in the figure, MSep@CTS exhibits the highest adsorption capacity for antimony at the optimal reaction pH of 3, with equilibrium adsorption capacities of 285.01 mg / g for Sb(III) and 426.35 mg / g for Sb(V).
[0039] The chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1 was applied, and the relationship between the adsorption capacity of the adsorbent for antimony and the adsorption time was determined. The application method is as follows:
[0040] Accurately transfer 100 mL of Sb(III) and Sb(V) solutions with an initial concentration of 100 mg / L into 250 mL Erlenmeyer flasks. Adjust the pH of the antimony ion wastewater to 3 with dilute hydrochloric acid solution. Add 20 mg of chitosan-modified magnetic sepiolite (MSep@CTS) prepared in Example 1 to each Erlenmeyer flask. React in a 25 ℃ air bath shaker for 24 h. Take 2 mL samples of the supernatant at 0, 10, 20, 30, 40, 60, 90, 120, 320, 420, 720, and 1440 min to determine the antimony ion concentration. Obtain the relationship between adsorption time and adsorption capacity, as shown below. Figure 3 As shown in the figure, Sb(III) reaches adsorption equilibrium in about 90 min, while Sb(V) reaches adsorption equilibrium in about 5 h.
[0041] The adsorbents prepared in Specific Example 1—sepiolite, magnetic sepiolite, and chitosan-modified magnetic sepiolite—were compared in application. The adsorption capacity of the adsorbents for antimony was determined. The application method was as follows:
[0042] Accurately transfer 100 mL of Sb(III) and Sb(V) solutions with an initial concentration of 100 mg / L into 250 mL Erlenmeyer flasks. Adjust the pH of the antimony ion wastewater to 3 using dilute hydrochloric acid solution. Add 20 mg of the prepared sepiolite (Sep), magnetic sepiolite (MSep), or chitosan-modified magnetic sepiolite (MSep@CTS) prepared in steps (1), (2), or (3) of Example 1 to the Erlenmeyer flasks. Shake the mixture in a 25 ℃ air bath shaker for 12 h. Measure the antimony ion concentration before and after the reaction to obtain the adsorption capacity of different adsorbents, such as... Figure 4 As shown, Sep's adsorption capacities for Sb(III) and Sb(V) were only 3.40 mg / g and 29.60 mg / g, respectively, while MSep@CTS significantly improved the adsorption capacities for Sb(III) and Sb(V), with equilibrium adsorption capacities of 279.80 mg / g and 440.66 mg / g, respectively, which are 82 times and 15 times that of the original Sep. This indicates that MSep@CTS has certain advantages in the field of antimony adsorption.
[0043] The chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1 was used for the simultaneous adsorption of Sb(III) and Sb(V):
[0044] The experiment was conducted with different concentration ratios of Sb(III) and Sb(V) as the sole control variable. Prepare 100 mL solutions of 100 mg / L Sb(III), 100 mL solutions of 80 mg / L Sb(III) and 20 mg / L Sb(V), 100 mL solutions of 60 mg / L Sb(III) and 40 mg / L Sb(V), 100 mL solutions of 50 mg / L Sb(III) and 50 mg / L Sb(V), 100 mL solutions of 40 mg / L Sb(III) and 60 mg / L Sb(V), 100 mL solutions of 20 mg / L Sb(III) and 80 mg / L Sb(V), and 100 mL solutions of 100 mg / L Sb(V). Place each solution in a 250 mL Erlenmeyer flask. Adjust the pH of the antimony ion wastewater to 3 using dilute hydrochloric acid solution. Add 20 mg / L Sb(V) solution to each Erlenmeyer flask. In specific Example 1, chitosan-modified magnetic sepiolite (MSep@CTS) was prepared and reacted in a 25 °C air bath shaker for 12 h. The antimony ion concentration before and after the reaction was measured to obtain the relationship between adsorption capacity and concentration ratio. Figure 5 As shown, when the concentration ratio of Sb(III) to Sb(V) is 1:4 and 1:9 (the concentration of Sb(III) is 20 mg / L and 10 mg / L, respectively), the total antimony adsorption capacity of M Sep@ CTS reaches 477.51 mg / g and 470.25 mg / g, respectively, which are higher than the adsorption capacities of Sb(III) and Sb(V) alone (289.75 mg / g and 451.84 mg / g). This indicates that M Sep@ CTS can synergistically adsorb antimony in both valence states.
[0045] The chitosan-modified magnetic sepiolite adsorbent prepared in Specific Example 1 was repeatedly regenerated and applied:
[0046] The chitosan-modified magnetic sepiolite adsorbent (MSep@CTS) prepared in Example 1, after adsorbing antimony ions using magnetic collection, was eluted with 0.1 mol / L NaOH solution, shaken for 4 h, and then magnetically separated. It was washed several times with water, dried under vacuum at 60 ℃, and cycled 5 times to test its reusability. 100 mL of Sb(III) and Sb(V) solutions with an initial concentration of 5 mg / L were accurately transferred and placed in 250 mL Erlenmeyer flasks. The pH of the antimony ion wastewater was adjusted to 3 with dilute hydrochloric acid solution. 20 mg of the eluted MSep@CTS was added to the Erlenmeyer flasks, and the reaction was carried out in a 25 ℃ air bath shaker for 12 h. The antimony ion concentration before and after the reaction was measured to obtain the relationship between the number of adsorbent recycling cycles and the adsorption capacity. Figure 6As shown in the figure, after five cycles of regeneration, the removal efficiency of MSep@CTS for low-concentration Sb(III) and Sb(V) solutions decreased from 100% to 82% and 78%, respectively, indicating that the adsorbent has excellent regeneration and reuse performance.
[0047] Figure 7 The image shows a TEM image of the chitosan-modified magnetic sepiolite adsorbent MSep@CTS prepared in Specific Example 1. The image shows that the lattice spacing of 0.25 nm corresponds to the (311) crystal plane of Fe3O4. Characterization analysis indicates that the chitosan-modified magnetic sepiolite composite material was successfully synthesized.
[0048] Figure 8 The image shows the infrared spectra of chitosan-modified magnetic sepiolite before and after adsorption of antimony ions prepared in Specific Example 1. As shown in the figure, MSep@CTS adsorbs Sb(III) and Sb(V) at 3437 cm⁻¹. -1 The NH / OH overlap peaks at [location] underwent a blue shift, moving to 3448 cm⁻¹. -1 and 3453 cm -1 The increased peak intensity at the adsorption site indicates that -OH and Sb-O may form Sb-OH bonds through hydrogen bonding. These results demonstrate that the -OH and -NH2 / -NH- functional groups play a crucial role in the adsorption of antimony. Furthermore, at 1047 cm⁻¹... -1 The shift in CO bonds indicates that oxygen-containing functional groups can adsorb Sb through surface complexation. Notably, after Sb(III) adsorption, the 1575 cm⁻¹... -1 The disappearance of the -C=N vibration peak at 636 cm⁻¹ indicates that -C=N plays an important role in Sb(III) adsorption. -1 734 cm -1 and 514 cm -1 609 cm -1 The observed new peak corresponds to Sb-O.
[0049] The steps in the method of this invention can be adjusted, combined, or deleted according to actual needs.
[0050] This document provides a detailed description and uses specific examples to illustrate the principles and implementation methods of the present invention. The above embodiments are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.
[0051] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.
Claims
1. A method for preparing a biopolymer chitosan-modified magnetic sepiolite adsorbent, characterized in that the method... include: S1. Place the sepiolite in a tube furnace protected by N2 and calcine it; S2. Ferric chloride hexahydrate and ferrous sulfate heptahydrate were mixed with sepiolite in deionized water, and magnetic sepiolite was obtained by co-precipitation. S3. Add magnetic sepiolite to chitosan solution and mix and crosslink at 85 °C for 20 h to obtain adsorbent.
2. The preparation method according to claim 1, characterized in that, Step S1 specifically involves placing sepiolite in a tube furnace protected by N2 and calcining it at 230 °C for 3 hours.
3. The preparation method according to claim 1, characterized in that, Step S2 specifically involves: mixing 2.3246 g of ferric chloride hexahydrate and 1.1954 g of ferrous sulfate heptahydrate in deionized water and ultrasonically dispersing for 30 min; then adding 2 g of sepiolite; stirring at room temperature for 1 h; adding concentrated ammonia dropwise to adjust the pH to 10; heating in a constant temperature water bath to 70 ℃ and continuing to stir for 1 h; aging at 60 ℃ for 1 h; and washing with deionized water until the supernatant is colorless to obtain magnetic sepiolite.
4. The preparation method according to claim 1, characterized in that, Magnetic sepiolite with a mass ratio of Fe3O4 to sepiolite of 1:2 was obtained.
5. The preparation method according to claim 1, characterized in that, The step S2 is followed by washing the magnetic sepiolite with deionized water until the supernatant is colorless, and then drying the resulting solid in a vacuum drying oven at 60 °C for 12 h after separation.
6. The preparation method according to claim 1, characterized in that, Step S3 specifically involves dissolving 0.5 g of chitosan in 60 mL of 2.5% acetic acid solution, dispersing the washed magnetic sepiolite in the above solution, stirring at room temperature for 60 min, adding 2 mL of 25% glutaraldehyde solution, and then mixing the solution at 85 °C for 20 h.
7. The preparation method according to claim 1, characterized in that, The step S3 is followed by: dispersing the obtained material in 100 mL of 1% sodium hydroxide, stirring at room temperature for 1-2 hours, washing with water until the supernatant is colorless, and drying and grinding under vacuum at 60 °C.
8. A method for applying a biopolymer chitosan-modified magnetic sepiolite adsorbent, characterized in that, The methods include: The adsorbent is added to the wastewater containing antimony ions for adsorption, and then the solid and liquid are separated after adsorption.