Preparation method and application of magnetic biomass carbon material

Abstract

The invention discloses a preparation method and application of a magnetic biomass carbon material (CaFe2O4-coated FNC), and belongs to the technical field of solid waste resourceful treatment.The preparation method avoids use of a calcium metal salt reagent, waste fish scales serve as a precursor, the fish scales contain collagen and hydroxyapatite, the collagen in the fish scales can be fully extracted through alkali treatment, and the magnetic biomass carbon material (CaFe2O4-coated FNC) is obtained. Forming an ichthine extracting solution (which is a collagen gel solution); residual filter residues are mainly hydroxyapatite and can be used as a high-efficiency phosphate fertilizer, high-value utilization of fish scales is realized, and the prepared magnetic biomass carbon material is a nitrogen-rich doped porous carbon material modified by nano-CaFe2O4, can effectively adsorb antibiotics and can be magnetically separated and recycled at the same time.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, and particularly relates to a method for preparing and applying magnetic biomass carbon materials. Background Technology

[0002] Quinolone antibiotics, represented by ciprofloxacin, are widely used in medical disease prevention, agricultural pest control, and livestock and aquaculture. However, antibiotics are not completely metabolized in humans and animals; approximately 80% of antibiotics entering the body are not absorbed, resulting in large amounts of antibiotic wastewater that seriously threatens human health and the stability of the ecological environment. Therefore, how to efficiently remove quinolone antibiotics has become a current research hotspot.

[0003] Quinolone antibiotics are stable and do not readily undergo hydrolysis. Commonly used treatment technologies include advanced oxidation, biodegradation, and adsorption. Among these, adsorption is a simple, mild, and low-cost method that does not produce toxic metabolites when removing low concentrations of antibiotics from water, making it widely used in antibiotic wastewater treatment. The efficiency of pollutant adsorption in antibiotic wastewater treatment depends not only on the pollutant concentration, adsorption time, and the physicochemical properties and pH of the solution, but also on the type, properties, and dosage of the adsorbent. The adsorbent is one of the most critical factors in the adsorption treatment of antibiotic wastewater. Therefore, current research and application of this technology mainly focus on the development and design of high-performance adsorbents.

[0004] Currently, Chinese patent CN119016055A discloses a magnetic composite photocatalyst based on biomass char and its preparation method. First, biomass char is obtained through the pyrolysis of straw, then impregnated with ferrous sulfate and zinc sulfate solutions, followed by a second pyrolysis to obtain the magnetic composite photocatalyst based on biomass char. This process is too long and has a long cycle time; moreover, the impregnation effect affects the uniformity of the magnetic material. Chinese patent CN113477214A discloses a preparation method and application of green nano-iron-based biomass char adsorbent material. First, waste tea leaves are pretreated and then pyrolyzed at high temperature to obtain biomass char. Then, an iron salt solution is added to the tea residue char, and under the action of tea polyphenols, a green nano-iron-based biomass char suspension is obtained. After washing with NaOH solution, ultrapure water, and anhydrous ethanol, it is magnetically separated again and vacuum freeze-dried to obtain green nano-iron-based biomass char that can be used as an adsorbent material. This process is complex, has a long cycle time, and consumes a lot of energy. Furthermore, the resulting nano-iron is unstable and prone to oxidation and agglomeration. Chinese patent CN117138754A discloses a method for preparing magnetic rice husk biochar based on KOH activation and its applications. First, rice husks are pyrolyzed at high temperature to produce biochar. Then, KOH is used for activation to create pores. Finally, the biochar is mixed with Fe3O4 and pyrolyzed to obtain magnetic rice husk biochar. This process is lengthy, and the activation process uses a large amount of alkaline reagent, resulting in low product yield and uneven distribution of magnetic elements. Furthermore, other related patents such as CN112108118A, CN115055164A, and CN111530419A, which prepare magnetic biochar composite materials, also suffer from complex processes, uneven distribution of magnetic components, and high energy consumption. Summary of the Invention

[0005] To address the problems of complex preparation processes and uneven distribution of magnetic components in existing magnetic biomass carbon materials, this invention provides a method for preparing magnetic biomass carbon materials and their applications. The magnetic biomass carbon materials prepared by this method can serve as high-performance magnetic adsorbents for antibiotics.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing magnetic biomass carbon materials, comprising the following steps:

[0008] Fish scales and alkaline solution were mixed and ultrasonically soaked. After solid-liquid separation, fish scale alkaline extract and filter residue were obtained.

[0009] The filter residue was soaked in an iron salt solution, and a mixed metal salt solution was obtained after solid-liquid separation.

[0010] The mixed metal salt solution is mixed with the fish scale alkaloid extract to obtain a mixed solution;

[0011] The mixed solution was subjected to hydrothermal treatment, and the product was washed and dried to obtain the magnetic biomass carbon material, denoted as CaFe2O4@FNC.

[0012] This invention uses fish scales as a precursor. Fish scales contain collagen and hydroxyapatite. Alkali treatment can fully extract the collagen, forming a fish scale alkaline extract (which is a collagen gel solution). The remaining filter residue is mainly hydroxyapatite, which can be used as a high-efficiency phosphate fertilizer, realizing the high-value utilization of fish scales. This invention utilizes the acidity of the iron salt solution itself to extract calcium from the hydroxyapatite in fish scales, forming an iron-calcium mixed metal salt solution. The partially decalcified hydroxyapatite can still be used as a high-efficiency phosphate fertilizer, while avoiding the additional use of calcium metal salt reagents, thus reducing costs. This invention fully dissolves the mixed metal salts in the fish scale alkaline extract, achieving atomic-level mixing of metal ions and carbon precursors. In the subsequent hydrothermal treatment process, it can achieve uniform dispersion of nano-CaFe2O4 on biomass carbon. At the same time, the content of magnetic components can be precisely controlled by simply adjusting the amount of metal salt, facilitating subsequent magnetic separation. This invention uses fish scale alkaloid extract (collagen gel solution) as a carbon source and transforms it into nitrogen-doped porous carbon material through a hydrothermal process. The uniformly distributed nitrogen atoms regulate the surface charge characteristics of the carbon material and simultaneously construct abundant oxygen-containing functional groups, which helps to improve the adsorption effect of magnetic biomass carbon materials on antibiotics (especially quinolone antibiotics).

[0013] Furthermore, the solid-liquid ratio of the fish scales to the alkaline solution is 1 g: (5~10) mL.

[0014] Furthermore, the concentration of the alkaline solution is 1.0~1.5 mol / L; the ultrasonic soaking time is 0.5~2 h.

[0015] Furthermore, the concentration of the iron salt solution is 0.1~0.15 mol / L; the soaking time of the filter residue with the iron salt solution is 10~30 min.

[0016] Furthermore, the iron salt solution is selected from ferric chloride solution or ferric acetate solution.

[0017] Furthermore, the temperature of the hydrothermal treatment is 170~190℃, and the time of the hydrothermal treatment is 10~14 h.

[0018] The present invention also provides a magnetic biomass carbon material prepared according to the above preparation method.

[0019] This invention also provides an antibiotic adsorbent, the raw material of which contains the aforementioned magnetic biomass carbon material. This invention introduces ferrates onto the surface of the carbon material, and the magnetization process also constructs a large number of functional groups such as -OH, -COOH, FeO, and FeOOH on the surface of the carbon material, effectively increasing the structural stability and surface adsorption sites of the carbon material, thereby improving the adsorption performance of the carbon material for antibiotics (especially quinolone antibiotics).

[0020] The present invention also provides an application of the above-mentioned magnetic biomass carbon material in the removal of antibiotics from water.

[0021] Furthermore, the amount of magnetic biomass carbon material added to the water is 1 g / (10~20) mL.

[0022] Furthermore, the antibiotic is a quinolone antibiotic.

[0023] For example, the quinolone antibiotic is selected from norfloxacin, ciprofloxacin, levofloxacin, or moxifloxacin.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] 1. This invention uses waste fish scales as a precursor. Fish scales contain collagen and hydroxyapatite. Alkali treatment can fully extract the collagen to form fish scale alkaline extract (which is a collagen gel solution). The remaining filter residue is mainly hydroxyapatite, which can be used as a high-efficiency phosphate fertilizer, thus realizing the high-value utilization of fish scales.

[0026] 2. This invention utilizes the acidity of the iron salt solution itself to extract calcium from hydroxyapatite in fish scales, forming a mixed iron-calcium metal salt solution. The partially decalcified hydroxyapatite can still be used as a high-efficiency phosphate fertilizer, while avoiding the additional use of calcium metal salt reagents and reducing costs.

[0027] 3. This invention fully dissolves the mixed metal salts into the fish scale alkali extract, achieving atomic-level mixing of metal ions and carbon precursors. This allows for uniform dispersion of nano-CaFe2O4 on biomass carbon during subsequent hydrothermal treatment. Furthermore, the content of magnetic components can be precisely controlled by adjusting the metal salt content, which is highly beneficial for subsequent magnetic separation.

[0028] 4. This invention uses fish scale alkaloid extract (collagen gel solution) as a carbon source, which is converted into nitrogen-doped porous carbon material through a hydrothermal process. The uniformly distributed nitrogen atoms will regulate the surface charge characteristics of the carbon material and at the same time construct abundant oxygen-containing functional groups, which helps to improve the adsorption effect of magnetic biomass carbon material on antibiotics (especially quinolone antibiotics).

[0029] 5. The magnetic biomass carbon material prepared by this invention is a nitrogen-rich doped porous carbon material (CaFe2O4@FNC) modified with nano-CaFe2O4, which can serve as an adsorbent for antibiotics (especially quinolones). The abundant nitrogen atoms in the magnetic biomass carbon material prepared by this invention can construct abundant oxygen-containing functional groups, serving as adsorption sites; the porous structure can effectively increase the specific surface area of ​​the material, shorten the diffusion path of antibiotics, and promote their adsorption and desorption processes on the material surface; the nano-CaFe2O4 can increase the magnetism of the biomass carbon material, and magnetic separation can enhance the solid-liquid separation effect, while simultaneously recovering the adsorbent, ultimately achieving the reuse of the adsorbent and efficient adsorption.

[0030] 6. The preparation process of the magnetic biomass carbon material of this invention is simple, requires little reagent, and is environmentally friendly. It only requires simple hydrothermal treatment to achieve controllable preparation of magnetic biomass carbon material. At the same time, the prepared magnetic biomass carbon material has a large specific surface area, good adsorption performance, and strong stability, which can provide certain theoretical reference for the development and design of other magnetic biomass carbon materials. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0032] Figure 1 Transmission electron microscopy (TEM) image of the magnetic biomass carbon material (CaFe2O4@FNC) prepared in Example 3;

[0033] Figure 2 The X-ray diffraction (XRD) pattern of the magnetic biomass carbon material (CaFe2O4@FNC) prepared in Example 3;

[0034] Figure 3 The graph shows the adsorption performance of ciprofloxacin on the magnetic biomass carbon material (CaFe2O4@FNC) prepared in Example 3.

[0035] Figure 4 Common ions (Ca) 2+ Mg 2+ K + Na + Cl - NO3 - SO4 2- PO4 3- CO3 2- HCO3 - The effect of the magnetic biomass carbon material (CaFe2O4@FNC) prepared in Example 3 on the adsorption performance of ciprofloxacin is shown in the figure.

[0036] Figure 5 The graph shows the reusability of the magnetic biomass carbon material (CaFe2O4@FNC) prepared in Example 3.

[0037] Figure 6 The graph shows the adsorption performance of ciprofloxacin on the magnetic calcium ferrite material (CaFe2O4) prepared in Comparative Example 1.

[0038] Figure 7 The adsorption performance of nitrogen-doped biomass carbon material (FNC) prepared for Comparative Example 2 on ciprofloxacin is shown in the figure.

[0039] Figure 8 The magnetic comparison diagram (left) of the magnetic biomass carbon material (CaFe2O4@FNC) prepared in Example 3 and the nitrogen-doped biomass carbon material prepared in Comparative Example 2, and the physical image of the magnetic biomass carbon material (CaFe2O4@FNC) (right). Detailed Implementation

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0042] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0043] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0044] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0045] An embodiment of the present invention provides a method for preparing magnetic biomass carbon materials, comprising the following steps:

[0046] Fish scales and alkaline solution were mixed and ultrasonically soaked. After solid-liquid separation, fish scale alkaline extract and filter residue were obtained.

[0047] The filter residue was soaked in an iron salt solution, and a mixed metal salt solution was obtained after solid-liquid separation.

[0048] The mixed metal salt solution was mixed with the fish scale alkaloid extract to obtain a mixed solution;

[0049] The mixed solution was subjected to hydrothermal treatment, and the product was washed and dried to obtain magnetic biomass carbon material, denoted as CaFe2O4@FNC.

[0050] In an embodiment of the present invention, the solid-liquid ratio of fish scales to alkaline solution is 1g:(5~10)mL.

[0051] In the embodiments of this invention, the fish scales are selected from one of the following: grass carp scales, silver carp scales, common carp scales, and tilapia scales. These fish scales contain collagen and hydroxyapatite. In this invention, alkali treatment can fully extract collagen from the fish scales, forming a fish scale alkali extract (which is a collagen gel solution); the remaining filter residue is mainly hydroxyapatite, which can be used as a high-efficiency phosphate fertilizer. This invention achieves high-value utilization of fish scales.

[0052] In the embodiments of the present invention, the concentration of the alkaline solution is 1.0~1.5 mol / L; the ultrasonic soaking time is 0.5~2 h.

[0053] In embodiments of the present invention, the alkaline solution is selected from at least one of KOH solution and NaOH solution.

[0054] In the embodiments of the present invention, the concentration of the iron salt solution is 0.1~0.15 mol / L; the soaking time of the filter residue with the iron salt solution is 10~30 min.

[0055] In embodiments of the present invention, the iron salt solution is selected from ferric chloride solution or ferric acetate solution.

[0056] In an embodiment of the present invention, the hydrothermal treatment temperature is 170~190℃ and the hydrothermal treatment time is 10~14 h.

[0057] In an embodiment of the present invention, deionized water and ethanol are used to wash the hydrothermal treatment product (hydrothermal treatment product).

[0058] Embodiments of the present invention also provide a magnetic biomass carbon material prepared according to the above preparation method.

[0059] Embodiments of the present invention also provide an antibiotic adsorbent, the raw materials of which contain the above-mentioned magnetic biomass carbon material.

[0060] Embodiments of the present invention also provide an application of the above-mentioned magnetic biomass carbon material in the removal of antibiotics from water.

[0061] In an embodiment of the present invention, the method for removing antibiotics from water using the above-mentioned magnetic biomass carbon material is as follows: Magnetic biomass carbon material (CaFe2O4@FNC) is added to antibiotic-containing wastewater for adsorption. After adsorption saturation, solid-liquid separation is performed using a magnet. The magnetic biomass carbon material can be regenerated after treatment with an ethanol solution; for example, it can be regenerated using the washing liquid from the heat treatment product of the washing water.

[0062] The magnetic biomass carbon material prepared by this invention is a nitrogen-rich doped porous carbon material (CaFe2O4@FNC) modified with nano-CaFe2O4, which can serve as an adsorbent for antibiotics (especially quinolones). The abundant nitrogen atoms in the magnetic biomass carbon material prepared by this invention can construct rich oxygen-containing functional groups, serving as adsorption sites; the porous structure can effectively increase the specific surface area of ​​the material, shorten the diffusion path of antibiotics, and promote their adsorption and desorption behavior on the material surface; the nano-CaFe2O4 can increase the magnetism of the biomass carbon material, and magnetic separation can be used to enhance the solid-liquid separation effect, while simultaneously recovering the adsorbent, ultimately achieving the reuse and efficient adsorption of the adsorbent.

[0063] In an embodiment of the present invention, the amount of magnetic biomass carbon material added to water is 1 mg / (10~20) mL, preferably 1 mg / 10 mL.

[0064] In embodiments of the present invention, the antibiotic is a quinolone antibiotic.

[0065] For example, the quinolone antibiotics are selected from norfloxacin, ciprofloxacin, levofloxacin, or moxifloxacin. In the following embodiments of the present invention, norfloxacin and ciprofloxacin are used as examples for performance verification.

[0066] Magnetic analysis for adsorbent recovery primarily utilizes magnetic or magnetizable materials as adsorbents, achieving separation and enrichment through an external magnetic field. In magnetic solid-phase extraction (M-SPE), a magnetic adsorbent is added to the sample solution or suspension, adsorbing the target analyte onto the dispersed surface of the magnetic adsorbent. Subsequently, under the influence of an external magnetic field, the target analyte migrates along with the adsorbent and is ultimately eluted by a suitable solvent, thus separating it from the sample matrix.

[0067] Unless otherwise specified, the room temperature in this invention is 25±2℃.

[0068] All raw materials used in the embodiments of the present invention were obtained through commercial purchase.

[0069] The technical solution of the present invention will be further illustrated by the following embodiments.

[0070] It should be noted that all aspects not described in detail in this invention are conventional operating methods in the field and are not the focus of this invention. For example, specific methods such as recovering adsorbents through magnetic analysis are all accomplished using conventional methods.

[0071] Example 1

[0072] A method for preparing magnetic biomass carbon materials, comprising the following steps:

[0073] 10 g of grass carp scales were added to 50 mL of 1.0 mol / L NaOH solution, with a solid-liquid ratio of 1:5 (g / mL). After ultrasonic soaking for 1 h, solid-liquid separation was performed to obtain a fish scale alkaloid extract. The filter residue was washed with water and set aside. The filter residue was added to 50 mL of 0.1 mol / L ferric chloride solution and ultrasonically soaked for 20 min. After filtration, a mixed metal salt solution was obtained. The mixed metal salt solution and the fish scale alkaloid extract were mixed to obtain a mixed solution. The mixed solution was transferred to a reactor for hydrothermal treatment at 170℃ for 10 h. The hydrothermal treatment product was repeatedly washed with deionized water and ethanol until neutral and dried overnight at 60℃ in a forced-air drying oven to obtain a magnetic biomass carbon material, denoted as CaFe2O4@FNC.

[0074] Taking norfloxacin as an example, the performance of the magnetic biomass carbon material (CaFe2O4@FNC) prepared in this embodiment in treating antibiotics was verified. The specific method is as follows:

[0075] Take 10 mg of CaFe2O4@FNC prepared in this example and add it to a conical flask containing 100 mL of norfloxacin aqueous solution. The initial concentration of norfloxacin aqueous solution is 20 mg / L. Then, a static adsorption experiment of antibiotic adsorption by magnetic biomass carbon material is carried out at 25°C (the above conical flask is placed in a constant temperature shaker and shaken at 150 r / min at 25°C until adsorption equilibrium is reached).

[0076] Within 2 hours, the CaFe2O4@FNC prepared in this embodiment achieved a removal rate of 93.15% for norfloxacin, with a saturated adsorption capacity of 186.3 mg / g, demonstrating that the CaFe2O4@FNC prepared in this embodiment can efficiently remove norfloxacin.

[0077] Example 2

[0078] A method for preparing magnetic biomass carbon materials, comprising the following steps:

[0079] 5g of grass carp scales were added to 40 mL of a mixed solution of KOH and NaOH (1:1 molar ratio of KOH to NaOH) with a concentration of 1.5 mol / L, and the solid-liquid ratio was controlled at 1:8 (g / mL). After ultrasonic soaking for 0.5 h, solid-liquid separation was performed to obtain fish scale alkaloid extract. The filter residue was washed with water and set aside. The filter residue was added to 50 mL of ferric chloride solution with a concentration of 0.15 mol / L, and ultrasonically soaked for 15 min. After filtration, a mixed metal salt solution was obtained. The mixed metal salt solution and the fish scale alkaloid extract were mixed to obtain a mixed solution. The mixed solution was transferred to a reaction vessel for hydrothermal treatment at a temperature of 180℃ for 14 h. The hydrothermal treatment product was repeatedly washed with deionized water and ethanol until neutral, and dried overnight at 60℃ in a forced-air drying oven to obtain magnetic biomass carbon material, denoted as CaFe2O4@FNC.

[0080] Taking ciprofloxacin as an example, the performance of the magnetic biomass carbon material (CaFe2O4@FNC) prepared in this embodiment in treating antibiotics was verified. The specific method is as follows:

[0081] Take 5 mg of CaFe2O4@FNC prepared in this example and add it to a conical flask containing 100 mL of ciprofloxacin aqueous solution. The initial concentration of ciprofloxacin aqueous solution is 10 mg / L. Then, a static adsorption experiment of antibiotic adsorption by magnetic biomass carbon material is carried out at 25°C (the above conical flask is placed in a constant temperature shaker and shaken at 150 r / min at 25°C until adsorption equilibrium is reached).

[0082] Within 2.0 h, the CaFe2O4@FNC prepared in this embodiment achieved a ciprofloxacin removal rate of up to 91.41% and a saturated adsorption capacity of 182.8 mg / g, demonstrating that the CaFe2O4@FNC prepared in this embodiment can efficiently remove ciprofloxacin.

[0083] Example 3

[0084] A method for preparing magnetic biomass carbon materials, comprising the following steps:

[0085] 5 g of tilapia scales were added to 50 mL of 1.5 mol / L KOH solution, with a solid-liquid ratio of 1:10 (g / mL). After ultrasonic soaking for 2 h, solid-liquid separation was performed to obtain tilapia scale alkaloid extract. The filter residue was washed with water and set aside. The filter residue was added to 50 mL of 0.1 mol / L ferric acetate solution and ultrasonically soaked for 20 min. After filtration, a mixed metal salt solution was obtained. The mixed metal salt solution and tilapia scale alkaloid extract were mixed to obtain a mixed solution. The mixed solution was transferred to a reactor for hydrothermal treatment at 190℃ for 12 h. The hydrothermal treatment product was repeatedly washed with deionized water and ethanol until neutral and dried overnight at 60℃ in a forced-air drying oven to obtain magnetic biomass carbon material, denoted as CaFe2O4@FNC.

[0086] The TEM image of the CaFe2O4@FNC prepared in this embodiment is shown below. Figure 1 As shown, nanoneedle-shaped CaFe2O4 aggregates to form nanoflowers, which are uniformly distributed on the porous biomass carbon matrix.

[0087] The XRD results of the CaFe2O4@FNC prepared in this embodiment are as follows: Figure 2 As shown, XRD also indicates that the material prepared in this embodiment is a composite of CaFe2O4 and carbon materials.

[0088] Taking ciprofloxacin as an example, the performance of the magnetic biomass carbon material (CaFe2O4@FNC) prepared in this embodiment in treating antibiotics was verified. The specific method is as follows:

[0089] Take 10 mg of CaFe2O4@FNC prepared in this example and add it to a conical flask containing 100 mL of ciprofloxacin aqueous solution. The initial concentration of ciprofloxacin aqueous solution is 25 mg / L. Then, a static adsorption experiment of antibiotic adsorption by magnetic biomass carbon material is carried out at 25 °C (the above conical flask is placed in a constant temperature shaker and shaken at 150 r / min at 25 °C until adsorption equilibrium is reached).

[0090] The adsorbed aqueous solution sample was filtered through a 0.45 μm filter membrane, and the absorbance was measured at a characteristic wavelength of 277 nm using a UV-Vis spectrophotometer. Relevant data were calculated, and each experiment was repeated three times, with the average value calculated. Figure 3 It can be seen that the removal rate of ciprofloxacin by CaFe2O4@FNC prepared in this embodiment is close to 60% in the first 20 minutes, and basically reaches adsorption saturation within 2 hours. The removal rate of ciprofloxacin by CaFe2O4@FNC is as high as 93.92%, and the corresponding saturation adsorption capacity is 234.8 mg / g, indicating that CaFe2O4@FNC prepared in this embodiment can efficiently remove ciprofloxacin.

[0091] To verify the effect of common ions on the adsorption performance of CaFe2O4@FNC on antibiotics, the following experiment was conducted using CaFe2O4@FNC prepared in Example 3 as an example: 10 mg of CaFe2O4@FNC was added to an Erlenmeyer flask containing 100 mL of ciprofloxacin aqueous solution. The initial concentration of the ciprofloxacin aqueous solution was 25 mg / L. Simultaneously, Ca... 2+ Mg 2+ K + Na + Cl - NO3 - SO4 2- PO4 3- CO3 2- Add to ciprofloxacin aqueous solution, controlling the ion concentration to 100 mg / L, where Cl - For concentrations of 100 mg / L and 3000 mg / L, conical flasks were placed in a constant-temperature shaker and shaken at 150 r / min at 25 °C until adsorption equilibrium was reached. The adsorbed aqueous samples were then filtered through a 0.45 μm filter membrane, and the absorbance was measured at a characteristic wavelength of 277 nm using a UV-Vis spectrophotometer. Relevant data were calculated, and each experiment was repeated three times, with the average value calculated.

[0092] Depend on Figure 4 Common ions such as Ca 2+ Mg 2+ K + Na + Cl - NO3 - SO4 2- PO4 3- CO3 2- The adsorption performance of CaFe2O4@FNC on antibiotics was almost unaffected; at an initial concentration of common ions of 100 mg / L, the removal rate of ciprofloxacin remained above 92%; even with Cl - Even at a concentration as high as 3 g / L, the removal rate of ciprofloxacin by CaFe2O4@FNC can still be maintained at 88.15%, indicating that the CaFe2O4@FNC prepared in this invention has a strong anti-interference ability against common ions and also exhibits strong salt tolerance, and can directly remove antibiotics such as ciprofloxacin from seawater aquaculture tailwater.

[0093] To assess the reusability of CaFe2O4@FNC, the following experiment was conducted using CaFe2O4@FNC prepared in Example 3 as an example: 10 mg of CaFe2O4@FNC was added to a conical flask containing 100 mL of ciprofloxacin aqueous solution (initial concentration: 25 mg / L). The flask was placed in a constant-temperature shaker and shaken at 150 r / min at 25°C until adsorption equilibrium was reached. The adsorbent was recovered by magnetic analysis and ultrasonically soaked in an ethanol solution (the washing liquid from the hydrothermal treatment product in Example 3) for 30 min. After filtration and drying, it was reused as an adsorbent for ciprofloxacin adsorption. This process was repeated four times.

[0094] Depend on Figure 5 It can be seen that CaFe2O4@FNC has excellent stability. After 5 cycles, the removal rate of ciprofloxacin by CaFe2O4@FNC can still be maintained above 90.5%, and the corresponding saturated adsorption capacity can be maintained above 226 mg / g.

[0095] Comparative Example 1

[0096] A method for preparing magnetic calcium ferrite material, comprising the following steps:

[0097] 5 g of tilapia scales were added to 50 mL of 0.2 mol / L HCl solution, with a solid-liquid ratio of 1:10 (g / mL). After stirring for 3 h, solid-liquid separation was performed to obtain a calcium extract of fish scales. Then, 50 mL of 0.2 mol / L ferric chloride solution was added to the calcium extract of fish scales, and the mixture was sonicated for 30 min to obtain a mixed metal salt solution. The pH of the mixed metal salt solution was then adjusted to 10. The mixed metal salt solution was transferred to a reaction vessel for hydrothermal treatment at 190℃ for 12 h. The hydrothermal treatment product was repeatedly washed with deionized water and ethanol until neutral, and then dried overnight at 60℃ in a forced-air drying oven to obtain magnetic calcium ferrite material, denoted as CaFe2O4.

[0098] Taking ciprofloxacin as an example, the performance of the magnetic calcium ferrite material (CaFe2O4) prepared in this comparative example in treating antibiotics was verified. The specific method is as follows:

[0099] Take 10 mg of the CaFe₂O₄ prepared in this comparative example and add it to a conical flask containing 100 mL of ciprofloxacin aqueous solution (initial concentration: 25 mg / L). Place the flask in a constant-temperature shaker and shake at 150 r / min at 25 °C until adsorption equilibrium is reached. Filter the adsorbed solution sample through a 0.45 μm filter membrane and measure the absorbance at a characteristic wavelength of 277 nm using a UV-Vis spectrophotometer. Calculate the relevant data. Repeat each experiment three times and calculate the average value.

[0100] Adsorption results are as follows Figure 6 As shown, the CaFe2O4 prepared in this comparative example exhibited poor removal performance for ciprofloxacin. After approximately 8 hours, the removal rate of ciprofloxacin by CaFe2O4 was only 7.15%, corresponding to a saturated adsorption capacity of 17.9 mg / g. This comparative example demonstrates that a single calcium ferrite component cannot effectively remove ciprofloxacin.

[0101] Comparative Example 2

[0102] A method for preparing nitrogen-doped biomass carbon materials, comprising the following steps:

[0103] 5 g of tilapia scales were added to 50 mL of 1.5 mol / L KOH solution, with a solid-liquid ratio of 1:10 (g / mL). After ultrasonic soaking for 2 h, solid-liquid separation was performed to obtain tilapia scale alkaloid extract. The pH of the tilapia scale alkaloid extract was adjusted to 10, and the solution was transferred to a reaction vessel for hydrothermal treatment at 190℃ for 12 h. The hydrothermal product was repeatedly washed with deionized water and ethanol until neutral, and then dried overnight at 60℃ in a forced-air drying oven to obtain nitrogen-doped biomass carbon material, denoted as FNC.

[0104] Taking ciprofloxacin as an example, the performance of the nitrogen-doped biomass carbon (FNC) material prepared in this comparative example in treating antibiotics was verified. The specific method is as follows:

[0105] Take 10 mg of FNC prepared in this comparative example and add it to a conical flask containing 100 mL of ciprofloxacin aqueous solution (initial concentration: 25 mg / L). Place the flask in a constant-temperature shaker and shake at 150 r / min at 25 °C until adsorption equilibrium is reached. Filter the adsorbed solution sample through a 0.45 μm filter membrane and measure the absorbance at a characteristic wavelength of 277 nm using a UV-Vis spectrophotometer. Calculate the relevant data. Repeat each experiment three times and calculate the average value.

[0106] Adsorption results are as follows Figure 7As shown, the FNC prepared in this comparative example exhibits certain adsorption performance for ciprofloxacin. After approximately 3 hours, the removal rate of ciprofloxacin by CaFe2O4 was 70.41%, corresponding to a saturated adsorption capacity of 170.2 mg / g, which is lower than the performance of the CaFe2O4@FNC prepared in Example 3 (234.8 mg / g). This comparative example further demonstrates the superiority of the present invention.

[0107] Figure 8 The image shows a magnetic comparison between the magnetic biomass carbon material (CaFe2O4@FNC) prepared in Example 3 and the nitrogen-doped biomass carbon material (FNC) prepared in Comparative Example 2. It can be seen that the present invention prepares magnetic biomass carbon material (CaFe2O4@FNC) by a one-step hydrothermal method. It has excellent magnetic properties and can achieve solid-liquid separation quickly through magnetic treatment, which facilitates the recycling of adsorbent.

[0108] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a magnetic biomass carbon material, characterized by, The method comprises the following steps: mixing fish scales and alkali solution, ultrasonic immersion, solid-liquid separation to obtain fish scale alkali extraction and residue; immersion of the residue with ferric salt solution, solid-liquid separation to obtain mixed metal salt solution; mixing the mixed metal salt solution with the fish scale alkali extraction to obtain a mixed solution; hydrothermal treatment of the mixed solution, washing and drying of the product to obtain the magnetic biomass carbon material.

2. The method of claim 1, wherein the magnetic biomass carbon material is prepared by the steps of: mixing a biomass material with a magnetic material; and heating the mixture to a temperature of 300- 1,000 °C in an inert atmosphere. The solid-liquid ratio of the fish scales to alkali solution is 1g:(5-10)mL.

3. The method of claim 2, wherein the magnetic biomass carbon material is prepared by the steps of: mixing a biomass material with a magnetic material; and heating the mixture to a temperature of 300- 1,000 °C in an inert atmosphere. The concentration of the alkali solution is 1.0-1.5 mol / L; the ultrasonic immersion time is 0.5-2 h.

4. The method of claim 1, wherein the magnetic biomass carbon material is prepared by the steps of: mixing a biomass material with a magnetic material; and heating the mixture to a temperature of 300- 1,000 °C in an inert atmosphere. The concentration of the ferric salt solution is 0.1-0.15 mol / L.

5. The method of claim 1, wherein the magnetic biomass carbon material is prepared by the steps of: mixing a biomass material with a magnetic material; and heating the mixture to a temperature of 300- 1,000 °C in an inert atmosphere. The hydrothermal treatment temperature is 170-190℃, and the hydrothermal treatment time is 10-14 h.

6. A magnetic biomass carbon material, characterized by, Prepared according to the preparation method of any one of claims 1-5.

7. An antibiotic adsorbent, characterized by, The raw material contains the magnetic biomass carbon material of claim 6.

8. Use of the magnetic biomass carbon material of claim 6 in removing antibiotics in water.

9. Use according to claim 8, characterized in that, The added amount of the magnetic biomass carbon material in water is 1mg / (10-20)mL.

10. Use according to claim 8, characterized in that, The antibiotic is quinolone antibiotic.

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