A composite material for adsorbing heavy metal ions in a traditional Chinese medicine water extract, a preparation method and application thereof

Abstract

The application provides a kind of composite material for adsorbing heavy metal ions in traditional Chinese medicine water extract and its preparation method and application, the composite material is MgAl-LDHs@FRBCs / Fe3O4, its preparation method includes the following steps: (1) traditional Chinese medicine residue is carbonized in nitrogen high temperature environment to obtain FRBCs. (2) FeCl3·6H2O and sodium acetate are dissolved in ethylene glycol, and Fe3O4 is prepared by hydrothermal method after being mixed and dispersed sufficiently. (3) magnesium chloride and aluminum chloride are dissolved in water containing FRBCs and Fe3O4, sodium hydroxide solution is added to adjust pH, and the composite material is obtained by in-situ growth under hydrothermal conditions. The composite material has the characteristics of large specific surface area, stable structure, high adsorption capacity, etc., and can simultaneously adsorb Pb 2+ , Cu 2+ , Cd 2+ , Ni 2+ 4 kinds of heavy metal ions in traditional Chinese medicine extract. The application has broad prospects in realizing the removal of heavy metals in traditional Chinese medicine extract and the reasonable application of traditional Chinese medicine residue.

Description

Technical Field

[0001] This invention belongs to the technical field of traditional Chinese medicine processing and the safety of traditional Chinese medicine preparations, specifically relating to a composite material for adsorbing heavy metal ions in aqueous extracts of traditional Chinese medicine, its preparation method and application. Background Technology

[0002] Heavy metals exhibit significant bioaccumulation and toxicological characteristics. Long-term intake may lead to liver and kidney damage, nervous system disorders, endocrine imbalances, and immune dysfunction, thus posing potential health risks. In recent years, the application of traditional Chinese medicine (TCM) and its preparations has been expanding globally, and the quality and safety of TCM have received increasing attention. Heavy metal contamination is considered a common concern in the quality control of TCM. Multiple studies have shown that heavy metal ions can be introduced during the planting, harvesting, processing, and storage of TCM materials. Therefore, effectively removing heavy metals from TCM extracts and preparations has become an important task for the modernization of TCM and the establishment of its quality standards.

[0003] Currently, common methods for removing heavy metal pollution include adsorption, ion exchange, precipitation, and membrane separation. Among these, adsorption is considered a promising method due to its simplicity, low cost, mild conditions, and potential for recyclability. However, existing commonly used adsorbents (such as activated carbon, resins, and metal oxides) still have drawbacks such as limited specific surface area, insufficient active sites, and difficulties in recovery, making it difficult to meet the treatment requirements of multi-metal, multi-component systems. Therefore, developing an adsorbent with widely available raw materials, low cost, the ability to simultaneously adsorb multiple heavy metals, and limited impact on active ingredients for the removal of heavy metal ions from traditional Chinese medicine extracts is of great significance for the safety of traditional Chinese medicine preparations. Summary of the Invention

[0004] To address the above problems, one objective of this invention is to provide a MgAl-LDHs@FRBCs / Fe3O4 composite material, characterized by being obtained through the following steps:

[0005] 1) Take Isatis leaf and Isatis root in a mass ratio of 1:1, add 10 times the mass of deionized water to decoct and obtain the residue. Crush the residue and pass it through a 100-mesh sieve to obtain the residue powder. Pyrolyze the residue powder at 600℃ for 2 hours under a nitrogen atmosphere. After natural cooling, wash with 10 wt% hydrochloric acid, then wash with ultrapure water and dry to obtain FRBCs.

[0006] Furthermore, the decoction of deionized water to obtain medicinal residue includes the steps of reflux for 2 hours, repeated decoction three times, and drying the medicinal residue at 60°C.

[0007] Furthermore, the pyrolysis described in step 1) is carried out in a tubular furnace;

[0008] Furthermore, the hydrochloric acid washing described in step 1) needs to be performed 3-5 times;

[0009] Furthermore, the ultrapure water washing described in step 1) needs to be washed until pH=7;

[0010] Furthermore, the drying conditions described in step 1) are drying at 80°C for 24 hours;

[0011] 2) FRBCs and Fe3O4 were ultrasonically dispersed in deionized water, and anhydrous MgCl2 and AlCl3·6H2O were added to the deionized water to obtain a mixed solution. The mixture was stirred and ultrasonically treated at room temperature, and the pH of the mixture was adjusted to 10 with 1 M NaOH aqueous solution. The mixture was then hydrothermally reacted at 180℃ for 24 hours, cooled, centrifuged, washed, and freeze-dried to obtain the MgAl-LDHs@FRBCs / Fe3O4 complex.

[0012] The ratio of FRBCs, Fe3O4 and deionized water is 1 g: 1 g: 100 mL;

[0013] The ratio of deionized water to anhydrous MgCl2 and AlCl3·6H2O was 100 mL:0.03 mol:0.01 mol.

[0014] Furthermore, the hydrothermal reaction at 180°C for 24 hours described in step 2) is carried out in a stainless steel hydrothermal reactor lined with polytetrafluoroethylene.

[0015] Furthermore, the cooling described in step 2) is cooling to room temperature.

[0016] Furthermore, the washing described in step 2) involves alternating washing with 0.1 wt% dilute hydrochloric acid and water.

[0017] Further, the Fe3O4 described in step 2) is obtained by the following steps: FeCl3·6H2O and CH3COONa are dissolved in ethylene glycol, stirred, and then transferred to a hydrothermal reactor lined with polytetrafluoroethylene. After being kept at 200°C for 10 hours, the mixture is naturally cooled to obtain a mixture. The mixture is thoroughly washed with water and ethanol and dried to obtain Fe3O4.

[0018] The ratio of FeCl3·6H2O, CH3COONa and ethylene glycol was 16.2 g:32.4 g:240 mL.

[0019] Furthermore, the stirring process needs to be carried out for 1 hour;

[0020] Furthermore, the stirring is carried out at 25°C;

[0021] Furthermore, the drying conditions are vacuum drying at 55°C for 15 hours;

[0022] The second objective of this invention is to provide a method for preparing MgAl-LDHs@FRBCs / Fe3O4 composite materials, comprising the following steps:

[0023] 1) Take Isatis leaf and Isatis root in a mass ratio of 1:1, add 10 times the mass of deionized water to decoct and obtain the residue. Crush the residue and pass it through a 100-mesh sieve to obtain the residue powder. Pyrolyze the residue powder at 600℃ for 2 hours under a nitrogen atmosphere. After natural cooling, wash with 10 wt% hydrochloric acid, then wash with ultrapure water and dry to obtain FRBCs.

[0024] Furthermore, the decoction of deionized water to obtain medicinal residue includes the steps of reflux for 2 hours, repeated decoction three times, and drying the medicinal residue at 60°C.

[0025] Furthermore, the pyrolysis described in step 1) is carried out in a tubular furnace;

[0026] Furthermore, the hydrochloric acid washing described in step 1) needs to be performed 3-5 times;

[0027] Furthermore, the ultrapure water washing described in step 1) needs to be washed until pH=7;

[0028] Furthermore, the drying conditions described in step 1) are drying at 80°C for 24 hours;

[0029] 2) FRBCs and Fe3O4 were ultrasonically dispersed in deionized water, and anhydrous MgCl2 and AlCl3·6H2O were added to the deionized water to obtain a mixed solution. The mixture was stirred and ultrasonically treated at room temperature, and the pH of the mixture was adjusted to 10 with 1 M NaOH aqueous solution. The mixture was then hydrothermally reacted at 180℃ for 24 hours, cooled, centrifuged, washed, and freeze-dried to obtain the MgAl-LDHs@FRBCs / Fe3O4 complex.

[0030] The ratio of FRBCs, Fe3O4 and deionized water is 1 g: 1 g: 100 mL;

[0031] The ratio of deionized water to anhydrous MgCl2 and AlCl3·6H2O was 100 mL:0.03 mol:0.01 mol.

[0032] Furthermore, the hydrothermal reaction at 180°C for 24 hours described in step 2) is carried out in a stainless steel hydrothermal reactor lined with polytetrafluoroethylene.

[0033] Furthermore, the cooling described in step 2) is cooling to room temperature.

[0034] Furthermore, the washing described in step 2) involves alternating washing with 0.1 wt% dilute hydrochloric acid and water.

[0035] Further, the Fe3O4 described in step 2) is obtained by the following steps: FeCl3·6H2O and CH3COONa are dissolved in ethylene glycol, stirred, and then transferred to a hydrothermal reactor lined with polytetrafluoroethylene. After being kept at 200°C for 10 hours, the mixture is naturally cooled to obtain a mixture. The mixture is thoroughly washed with water and ethanol and dried to obtain Fe3O4.

[0036] The ratio of FeCl3·6H2O, CH3COONa and ethylene glycol was 16.2 g:32.4 g:240 mL.

[0037] Furthermore, the stirring process needs to be carried out for 1 hour;

[0038] Furthermore, the stirring is carried out at 25°C;

[0039] Furthermore, the drying conditions are vacuum drying at 55°C for 15 hours;

[0040] The third objective of this invention is to provide the application of the aforementioned composite material in the adsorption of heavy metal ions in aqueous extracts of traditional Chinese medicine.

[0041] Furthermore, the heavy metal ions include Pb. 2+ Cu 2+ Cd 2+ and Ni 2+ At least one of them.

[0042] Furthermore, the Chinese herb mentioned is Chuanxiong (Ligusticum striatum).

[0043] The fourth objective of this invention is to provide a method for adsorbing heavy metal ions in aqueous extracts of traditional Chinese medicine. The composite material described above is added to the aqueous extract of traditional Chinese medicine, ultrasonically dispersed at room temperature, and then placed in a constant temperature shaker for oscillation, thereby completing the adsorption of heavy metal ions in the aqueous extract of traditional Chinese medicine.

[0044] Furthermore, the ultrasonic dispersion time is 30 min;

[0045] Furthermore, the constant temperature is 25℃~45℃;

[0046] Preferably, the constant temperature is 25°C;

[0047] Furthermore, the oscillation condition is oscillation for 30 minutes to 12 hours;

[0048] Preferably, the oscillation condition is oscillation for 4 hours;

[0049] Furthermore, the filtration is performed using a 0.22 μm filter membrane;

[0050] Furthermore, the ratio of heavy metal ions in the composite material to those in the traditional Chinese medicine extract is 2 mg:1 mg.

[0051] This invention provides a composite material for adsorbing heavy metal ions in aqueous extracts of traditional Chinese medicine, its preparation method, and its application. The preparation method of this composite material is simple and can effectively adsorb heavy metal ions (Pb) in aqueous extracts of traditional Chinese medicine. 2+ Cu 2+ Cd 2+ and Ni 2+ It can adsorb heavy metal ions, has good recyclability and reusability, and has no significant impact on the content of the main active ingredients in traditional Chinese medicine. It has broad prospects for the application of adsorbing heavy metal ions in aqueous extracts of traditional Chinese medicine. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the preparation and heavy metal adsorption process of the MgAl-LDHs@FRBCs / Fe3O4 composite material of the present invention;

[0053] Figure 2 The X-ray diffraction patterns of MgAl-LDHs, FRBCs, Fe3O4 and MgAl-LDHs@FRBCs / Fe3O4 composite materials of the present invention are shown below.

[0054] Figure 3 The graph shows the adsorption efficiency of Pb, Cu, Cd and Ni ions in the aqueous extract of Ligusticum chuanxiong in this invention, which is composed of MgAl-LDHs, FRBCs, Fe3O4 and MgAl-LDHs@FRBCs / Fe3O4 composite material.

[0055] Figure 4 The graph shows the adsorption efficiency of Pb, Cu, Cd and Ni ions in five rounds of adsorption-desorption of the MgAl-LDHs@FRBCs / Fe3O4 composite material of this invention.

[0056] Figure 5 This is a high-performance liquid chromatography (HPLC) fingerprint of the aqueous extract of Ligusticum chuanxiong before and after heavy metal adsorption in this invention. Detailed Implementation

[0057] The present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of application of the present invention. The present invention is not limited to the following embodiments or examples. Any modifications and variations made without departing from the spirit of the present invention should be included within the scope of the present invention. Unless otherwise specified, the experimental materials or reagents used in the following embodiments are all conventional commercially available products.

[0058] The preparation of MgAl-LDHs@FRBCs / Fe3O4 composite material and its adsorption of heavy metal ions in aqueous extracts of traditional Chinese medicine are illustrated in the flowchart below. Figure 1 As shown, the specific steps are as follows:

[0059] (1) Preparation of Isatis folium-Isatis tinctoria biochar: Isatis folium (dried leaves of Isatis indigotica Fort., a plant of the Brassicaceae family, purchased from Chongqing Caiyuanba Traditional Chinese Medicine Market, originating from Anguo, Hebei Province) and Isatis tinctoria root (dried roots of Isatis tinctoria, a plant of the Brassicaceae family, purchased from Chongqing Caiyuanba Traditional Chinese Medicine Market, originating from Anguo, Hebei Province) were placed in a round-bottom flask at a mass ratio of 1:1, and 10 times the mass of deionized water was added. The mixture was refluxed for 2 hours and decocted three times. The residue was dried at 60°C. The residue was pulverized and passed through a 100-mesh sieve, and the powder was collected for later use. The powder was pyrolyzed in a tube furnace at 600°C for 2 hours under a nitrogen atmosphere, and then naturally cooled to room temperature to form carbonized material. The carbonized material was then washed 3-5 times with 10 wt% hydrochloric acid, followed by washing with ultrapure water until pH=7, and then dried at 80℃ for 24 hours. The resulting product was denoted as FRBCs.

[0060] (2) Preparation of Fe3O4: FeCl3·6H2O (16.2 g) and CH3COONa (32.4 g) were dissolved in 240 mL of ethylene glycol and stirred at 25 °C for 1 hour. Then the mixture was transferred to a hydrothermal reactor lined with polytetrafluoroethylene and kept at 200 °C for 10 hours. After naturally cooling to room temperature, the mixture was obtained. The mixture was thoroughly washed with water and ethanol and then vacuum dried at 55 °C for 15 hours to obtain Fe3O4.

[0061] (3) Preparation of MgAl-LDHs@FRBCs / Fe3O4 composite material: FRBCs (1 g) and Fe3O4 (1 g) were ultrasonically dispersed in 100 mL of deionized water to obtain a suspension. Then, 0.03 mol MgCl2 and 0.01 mol AlCl3·6H2O (Al2O3·6H2O) anhydrous were added to the suspension. 3+ Mg 2+ The mixture was stirred vigorously at room temperature (ratio 1:3) and sonicated for 30 min to ensure complete dissolution of MgCl2 and AlCl3·6H2O. The pH of the mixture was then adjusted to 10 with 1 M NaOH aqueous solution, transferred to a PTFE-lined stainless steel hydrothermal reactor, and hydrothermally reacted at 180 °C for 24 h. After natural cooling to room temperature, the resulting MgAl-LDHs@FRBCs / Fe3O4 composite material was collected by centrifugation, washed several times with alternating 0.1 wt% dilute hydrochloric acid and water, and then freeze-dried.

[0062] MgAl-LDHs were prepared using the same method, but without the addition of FRBCs and Fe3O4. The main steps are as follows: Anhydrous MgCl2 (0.03 mol) and AlCl3·6H2O (0.01 mol) were added to 100 mL of deionized water. The mixture was vigorously stirred and sonicated for 30 min at room temperature to ensure complete dissolution of MgCl2 and AlCl3·6H2O. Subsequently, the pH of the mixture was adjusted to 10 with NaOH aqueous solution (1 M), and the mixture was transferred to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The hydrothermal reaction was carried out at 180 °C for 24 hours. After natural cooling to room temperature, the obtained MgAl-LDHs were collected by centrifugation, washed several times with alternating water and 0.1 wt% dilute hydrochloric acid, and then freeze-dried.

[0063] (4) The FRBCs, Fe3O4, MgAl-LDHs and MgAl-LDHs@FRBCs / Fe3O4 composite materials prepared in (1)-(3) were characterized by X-ray diffraction (XRD). The results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the composite material has a stable structure, the original crystal structure of each component is maintained during the composite process, and no new impurity phases are introduced.

[0064] (5) Preparation of the herbal extract (i.e., aqueous extract): The herbal medicine Ligusticum chuanxiong was pulverized and sieved (60 mesh). Deionized water was added at a solid-liquid ratio of 1g:10mL, and the extract was continuously refluxed in a reflux apparatus for 2 hours. The temperature was adjusted to maintain the system at a slight boiling state. After extraction, the extract was filtered while hot, and the filtrate was centrifuged at high speed to remove solid impurities, thus obtaining the Ligusticum chuanxiong extract. Pb solutions with a concentration of 100 μg / mL were prepared. 2+ Cu 2+ Cd 2+ and Ni 2+ Take 0.4 mL of the above heavy metal mother liquor and add it to 40 mL of Ligusticum chuanxiong extract to reduce the Pb concentration in the extract. 2+ Cu 2+ Cd 2+ and Ni 2+ The ion spiking concentration was 1 μg / mL, and this spiked Ligusticum chuanxiong extract was used as the Chinese herbal extract for subsequent experiments (concentration C1).

[0065] (6) Heavy metal adsorption and removal: 80 mg of the prepared MgAl-LDHs@FRBCs / Fe3O4 composite material was added to 40 mL of traditional Chinese medicine extract and ultrasonically dispersed at room temperature for 30 min to ensure uniform distribution of the material in the extract. The system was then placed in a constant temperature shaker at 25℃ and shaken for 4 h. After shaking, a water extract of traditional Chinese medicine that had adsorbed heavy metal ions was obtained. This water extract was separated by high-speed centrifugation and filtered through a 0.22 μm filter membrane to obtain a supernatant with heavy metals removed.

[0066] The comparative example is the adsorption of heavy metals in the Chinese herbal extract obtained in step (5) using MgAl-LDHs, FRBCs, and Fe3O4. The steps are the same as those for the adsorption of heavy metals by the MgAl-LDHs@FRBCs / Fe3O4 composite material, except that the MgAl-LDHs@FRBCs / Fe3O4 composite material is replaced with MgAl-LDHs, FRBCs, or Fe3O4. The amount of MgAl-LDHs, FRBCs, and Fe3O4 added is the same as the amount of MgAl-LDHs@FRBCs / Fe3O4 composite material added, that is, 80 mg of each material is added to 40 mL of the Chinese herbal extract.

[0067] (7) Sample digestion: Take 2 mL (volume V1) of the supernatant after heavy metal removal from the above four materials and place it in a digestion vessel for digestion treatment to fully convert the metal ions and residual organic matter into measurable forms. Add 2.5 times the volume of concentrated nitric acid and an appropriate amount of hydrogen peroxide to obtain a mixed solution. Place the mixed solution on a ceramic heating plate and heat at 130°C for 0.5 h for pre-digestion. After natural cooling, transfer it to a microwave digester and digest it by gradient heating from 50°C to 185°C to obtain a digestion solution.

[0068] (8) ICP-MS detection: The digestion solution was diluted to 10 mL with 1% dilute nitric acid and used as the test solution for determination of heavy metal content (C2) on an inductively coupled plasma mass spectrometer (ICP-MS).

[0069] The formula for calculating adsorption efficiency is:

[0070]

[0071] The calculated adsorption efficiency, such as Figure 3 As shown, among the three materials FRBCs, Fe3O4, and MgAl-LDHs, only FRBCs are effective against Cu. 2+ It exhibits adsorption properties, but the adsorption efficiency is only 14.59%. The MgAl-LDHs@FRBCs / Fe3O4 composite material has an adsorption effect on Cu... 2+The adsorption efficiency reached 78.49%; among the three materials FRBCs, Fe3O4, and MgAl-LDHs, only FRBCs and Fe3O4 showed good adsorption for Ni. 2+ It exhibits adsorption properties, but the adsorption efficiencies are only 1.99% and 2.16%. The MgAl-LDHs@FRBCs / Fe3O4 composite material exhibits adsorption properties for Ni... 2+ The adsorption efficiency reached 35.48%; the composite material showed significantly better adsorption capacity for each ion in the Ligusticum chuanxiong extract than any other single material, with adsorption efficiencies of 96.53% (Pb). 2+ ), 78.49% (Cu 2+ ), 83.82% (Cd 2+ ), 35.48% (Ni 2+ ).

[0072] (9) Regeneration performance of MgAl-LDHs@FRBCs / Fe3O4 composite material: Based on the optimal experimental conditions, adsorption experiments were conducted in 40 mL of Ligusticum chuanxiong extract with a heavy metal ion spike concentration of 1 μg / mL. After adsorption, desorption was performed with 1% nitric acid, followed by multiple washings with deionized water. The material was then freeze-dried, and the adsorption-desorption process was repeated 5 times to determine the adsorption efficiency. The results are as follows: Figure 4 As shown. After 5 cycles of adsorption-desorption, the MgAl-LDHs@FRBCs / Fe3O4 composite material showed improved adhesion to Pb. 2+ Cu 2+ Cd 2+ and Ni 2+ The adsorption efficiencies were essentially the same, indicating that the material has good recyclability and reusability.

[0073] (10) Effect of composite materials on the effective components of Ligusticum chuanxiong extract during heavy metal adsorption: The content and fingerprint of active components of Ligusticum chuanxiong Hort. were determined by high performance liquid chromatography (HPLC) equipped with a 2998 photodiode array (PDA) detector. The chromatographic column was a Waters SunFire C18 column (150 × 4.6 mm, 5 μm), the mobile phase was methanol (organic phase) - 0.1% phosphoric acid aqueous solution (aqueous phase), the detection wavelength was 276 nm, the flow rate was 0.8 mL / min, and the injection volume was 10 μL. The content of each active component was calculated based on the standard curve by measuring the chromatographic peak area, and the similarity of the fingerprint spectra of each group was calculated using the relative peak area normalization method. Figure 5As shown, the average fingerprint similarity of the aqueous extract of Ligusticum chuanxiong before and after heavy metal adsorption was 99.8%. This result indicates that after the composite material of the present invention was used to adsorb heavy metals in the aqueous extract of Ligusticum chuanxiong, the number of major chromatographic peaks and the relative peak area of ​​the aqueous extract of Ligusticum chuanxiong did not change significantly (n=6), further confirming that the composite material treatment had no significant effect on the content of the main active ingredients in the traditional Chinese medicine.

[0074] The conventional techniques and solutions not described in detail in the above embodiments are all well known in the art, and therefore will not be elaborated upon here. The above embodiments and / or experimental examples describe the preferred embodiments of the present invention in detail. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A MgAl-LDHs@FRBCs / Fe3O4 composite material, characterized in that, It is prepared by the following steps: 1) Take Isatis leaf and Isatis root in a mass ratio of 1:1, add 10 times the mass of deionized water to decoct and obtain the residue. Crush the residue and pass it through a 100-mesh sieve to obtain the residue powder. Pyrolyze the residue powder at 600℃ for 2 hours under a nitrogen atmosphere. After natural cooling, wash with 10 wt% hydrochloric acid, then wash with ultrapure water and dry to obtain FRBCs. 2) FRBCs and Fe3O4 were ultrasonically dispersed in deionized water, and anhydrous MgCl2 and AlCl3·6H2O were added to the deionized water to obtain a mixed solution. The mixture was stirred and ultrasonically treated at room temperature, and the pH of the mixture was adjusted to 10 with 1 M NaOH aqueous solution. The mixture was then hydrothermally reacted at 180℃ for 24 hours, cooled, centrifuged, washed, and freeze-dried to obtain the MgAl-LDHs@FRBCs / Fe3O4 complex. The ratio of FRBCs, Fe3O4 and deionized water is 1 g: 1 g: 100 mL; The ratio of deionized water to anhydrous MgCl2 and AlCl3·6H2O was 100 mL:0.03 mol:0.01 mol.

2. The composite material as described in claim 1, characterized in that, The Fe3O4 described in step 2) is prepared by the following steps: FeCl3·6H2O and CH3COONa are dissolved in ethylene glycol, stirred, and then transferred to a hydrothermal reactor lined with polytetrafluoroethylene. After being kept at 200°C for 10 hours, the mixture is naturally cooled to obtain a mixture. The mixture is thoroughly washed with water and ethanol and dried to obtain Fe3O4. The ratio of FeCl3·6H2O, CH3COONa and ethylene glycol was 16.2 g:32.4 g:240 mL.

3. A method for preparing a MgAl-LDHs@FRBCs / Fe3O4 composite material, characterized in that, Includes the following steps: 1) Take Isatis leaf and Isatis root in a mass ratio of 1:1, add 10 times the mass of deionized water to decoct and obtain the residue. Crush the residue and pass it through a 100-mesh sieve to obtain the residue powder. Pyrolyze the residue powder at 600℃ for 2 hours under a nitrogen atmosphere. After natural cooling, wash with 10 wt% hydrochloric acid, then wash with ultrapure water and dry to obtain FRBCs. 2) FRBCs and Fe3O4 were ultrasonically dispersed in deionized water, and anhydrous MgCl2 and AlCl3·6H2O were added to the deionized water to obtain a mixed solution. The mixture was stirred and ultrasonically treated at room temperature, and the pH of the mixture was adjusted to 10 with 1 M NaOH aqueous solution. The mixture was then hydrothermally reacted at 180℃ for 24 hours, cooled, centrifuged, washed, and freeze-dried to obtain the MgAl-LDHs@FRBCs / Fe3O4 complex. The ratio of FRBCs, Fe3O4 and deionized water is 1 g: 1 g: 100 mL; The ratio of deionized water to anhydrous MgCl2 and AlCl3·6H2O was 100 mL:0.03 mol:0.01 mol.

4. The preparation method according to claim 3, characterized in that, The Fe3O4 described in step 2) is obtained by the following steps: FeCl3·6H2O and CH3COONa are dissolved in ethylene glycol, stirred, and then transferred to a hydrothermal reactor lined with polytetrafluoroethylene. After being kept at 200°C for 10 hours, the mixture is naturally cooled to obtain a mixture. The mixture is thoroughly washed with water and ethanol and dried to obtain Fe3O4. The ratio of FeCl3·6H2O, CH3COONa and ethylene glycol was 16.2 g:32.4 g:240 mL.

5. The application of the composite material according to claim 1 in the adsorption of heavy metal ions in aqueous extracts of traditional Chinese medicine.

6. The application as described in claim 5, characterized in that, The heavy metal ions include Pb. 2+ Cu 2+ Cd 2+ and Ni 2+ At least one of them.

7. The application as described in claim 5, characterized in that, The Chinese herb mentioned is Chuanxiong (Ligusticum striatum).

8. A method for adsorbing heavy metal ions from aqueous extracts of traditional Chinese medicine, characterized in that, The composite material described in claim 1 is added to the aqueous extract of traditional Chinese medicine, ultrasonically dispersed at room temperature, and then placed in a constant temperature shaker for oscillation, thereby completing the adsorption of heavy metal ions in the aqueous extract of traditional Chinese medicine. The ratio of heavy metal ions in the composite material to those in the traditional Chinese medicine extract is 2 mg:1 mg.

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