Method for simply and conveniently preparing capacitive deionization high-efficiency defluorination anode material based on waste biomass enteromorpha
By preparing a hierarchical porous bio-derived carbon material from Ulva prolifera as a capacitive deionization anode, the problem of insufficient defluorination performance in existing technologies has been solved, enabling efficient defluorination and environmentally friendly large-scale production.
Patent Information
- Application Number
- CN202511574894.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2026-01-23
AI Technical Summary
The lack of efficient anode materials in existing technologies limits the large-scale application of capacitive deionization technology in removing anions from water, especially in the field of defluorination. Furthermore, traditional preparation processes lead to the deterioration of the pore structure of carbon materials, making it difficult to meet the needs of large-scale production.
Using Ulva prolifera biomass as raw material, Ulva prolifera bio-derived carbon material was prepared by combining carbonization and freeze-drying to form a hierarchical porous structure. This material was then mixed with polyvinylidene fluoride and carbon black to form an electrode, thereby optimizing the pore size and surface properties of the material to improve its defluorination performance.
The study achieved highly efficient fluoride removal performance of Ulva prolifera bio-derived carbon materials in capacitive deionization technology, with a fluoride removal capacity of 37.41 mg g-1. The material preparation is simple and easy, suitable for large-scale production, reduces carbon emissions, is environmentally friendly, and enhances the potential for industrial application.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of capacitive deionization water treatment, in particular to a method for simply preparing a capacitive deionization high-efficiency fluorine removal anode material based on discarded biomass Enteromorpha. BACKGROUND
[0002] As an innovative desalination process based on the principle of electrochemical double layer, the capacitive deionization technology completes water purification through the ion electric adsorption mechanism driven by the electrode interface electric field. The technology has a unique ion migration-capture characteristic, and has a significant energy efficiency advantage in the process of brackish water desalination, and avoids the secondary pollution risk of the traditional membrane separation process. With the help of the technology, there is also a high-efficiency removal method for some difficult-to-remove ions in water bodies, such as heavy metal ions and halogen ions. The ion removal capacity of the capacitive deionization technology almost completely depends on the properties of the electrode material, and there is almost no carbon material product that can be used as an anode material at present, which restricts the large-scale application of the technology in removing anions in water bodies.
[0003] Since the first large-scale outbreak of Enteromorpha green tide in the Yellow Sea of China in 2007, the situation has been getting worse year by year. The ecological disaster formed by these marine macroalgae not only destroys the balance of the near-shore ecology, but also has multiple negative impacts on the coastal economy due to the sulfides produced by the decay.
[0004] In the modification of the biochar electrode and the capacitive deionization performance research, Wang Shiqin uses Enteromorpha biomass as the carbon source, selects three activators of KOH, H3PO4 and ZnCl2 to modify and prepare porous biomass carbon, and loads manganese dioxide on the basis of the modification, and studies the characterization structure and capacitive deionization performance. However, the existing technology only stays in the CDI desalination field for the research on Enteromorpha-derived carbon, because the biomass carbon material prepared by the existing process is limited by its own characteristics and has no advantage in the field of CDI fluorine removal. SUMMARY
[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a method for simply preparing a capacitive deionization high-efficiency fluorine removal anode material based on discarded biomass Enteromorpha. The present application proposes a collaborative innovation strategy of ecological governance and resource utilization, uses the natural salt enrichment characteristics and unique structural polysaccharide components (cellulose content of 32.7%, hemicellulose content of 21.4%) of Enteromorpha biomass, and the organic macromolecular carbon skeleton of the biomass can spontaneously form a hierarchical porous network in the process of thermal conversion and freeze-drying, which provides the possibility of using the biomass as a functional carbon material, and realizes the efficient removal of inorganic fluorine ions when the biomass is used as a capacitive deionization anode material.
[0006] A preparation method of Enteromorpha biomass-derived carbon, the method comprising the following steps:
[0007] S1, dry enteromorpha powder is placed in a nitrogen atmosphere, heated to 650-950℃, carbonization to obtain enteromorpha carbonization product;
[0008] S2, the enteromorpha carbonization product is washed with deionized water, and then freeze-dried to obtain enteromorpha biological derivative carbon.
[0009] As a preferred scheme of the present application, in step S1, the heating rate is 5 ℃ / min.
[0010] As a preferred scheme of the present application, in step S1, the carbonization time is 1 h.
[0011] As a preferred scheme of the present application, in step S1, the enteromorpha dry powder is prepared by washing fresh enteromorpha collected from water, air-drying, and then crushing into powder and passing through a 100-200 mesh screen.
[0012] As a preferred scheme of the present application, in step S2, the freeze-drying temperature is-45℃; the freeze-drying time is 30 h. Through the freeze-drying of the present application, the pore size characteristics in the material can be maximally preserved and optimized, making it more suitable as a CDI electrode material.
[0013] The enteromorpha biological derivative carbon prepared by the foregoing method and its use in the anode for capacitive deionization fluorine removal also belong to the protection scope of the present application.
[0014] In addition, the present application also provides an electrode for capacitive deionization fluorine removal, which is prepared by mixing the foregoing enteromorpha biological derivative carbon, polyvinylidene fluoride and carbon black in N-methyl pyrrolidone, stirring, and then making the sample into a sheet material and drying; thus obtaining.
[0015] As a preferred scheme of the present application, the amount ratio of the enteromorpha biological derivative carbon, polyvinylidene fluoride, carbon black and N-methyl pyrrolidone is 6-8 g: 1-3 g: 1 g: 1.4-2.0 mL.
[0016] As a preferred scheme of the present application, the stirring is magnetic stirring for 7-9 hours.
[0017] As a preferred scheme of the present application, the drying temperature is 60-70 ℃, and the drying time is 10-12 h.
[0018] Due to the adoption of the above technical scheme, the present application has the following beneficial effects:
[0019] 1. Compared with the problem that the pore structure of carbon material is deteriorated due to carbonization and drying parameter out of control in the traditional process, the multi-level pore structure of Enteromorpha biological derived carbon can be stably formed by the combination of carbonization and freeze drying and accurate parameter control, the structure makes the material have excellent ion adsorption capacity in CDI defluorination, and the defluorination performance can reach 37.41 mg g -1 ;
[0020] 2. The Enteromorpha biological derived carbon material obtained by the combination of the above technologies has high defluorination capacity, and the removal amount of fluorine ions is 5-6 times that of similar materials; can be used as an anode material and a carbon precursor for capacitive deionization technology;
[0021] 3. The preparation method of the present application has simple equipment and simple process, is suitable for large-scale batch production, greatly reduces the carbon emission in the traditional preparation method, and significantly improves the industrialization application potential of the environment-friendly production mode, and can meet the technical requirements of large-scale clean production. BRIEF DESCRIPTION OF DRAWINGS
[0022] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:
[0023] Figure 1 The pore size distribution diagram of the Enteromorpha biological derived carbon of the present application;
[0024] Figure 2 The CDI defluorination capacity columnar diagram of the Enteromorpha biological derived carbon electrode of Example 1 in 100 mg L-1 NaF solution under 0.8-1.4 V voltage;
[0025] Figure 3 The CDI defluorination capacity comparison diagram of the Enteromorpha biological derived carbon electrodes of Examples 1-4 in 100 mg L -1 NaF solution under 0.8-1.4 V voltage. DETAILED DESCRIPTION
[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments.
[0027] Example 1
[0028] In this embodiment, the Enteromorpha biological derived carbon electrode is used as an anode, and the activated carbon electrode is used as a cathode, and a working voltage of 0.8-1.4 V is applied to realize efficient removal of fluorine ions in water.
[0029] The Enteromorpha biological derived carbon electrode is prepared by the following method:
[0030] (1) After washing and air-drying the fresh seaweed collected from the water, it is crushed into powder using a pulverizer and sieved through a 100-mesh sieve to obtain dried seaweed powder.
[0031] (2) Weigh 10g of dried seaweed powder and put it into a tube furnace. Heat it to 950℃ at 5℃ / min under a nitrogen atmosphere and hold it for 1h.
[0032] (3) The above product was washed with deionized water, and after washing, it was freeze-dried at -45℃ for 30h. The dried product was then ground to obtain Ulva prolifera bio-derived carbon powder.
[0033] Figure 1 This is a pore size distribution diagram of bio-derived carbon from *Ulva prolifera* in this embodiment; as shown... Figure 1 As shown, the pore size distribution of the bio-derived carbon from *Ulva prolifera* in this embodiment is superior to that of the comparative example, with an average pore size of 8.3963 nm.
[0034] Table 1 shows the surface element content of the material obtained by XPS testing of the bio-derived carbon from *Ulva prolifera* in this embodiment.
[0035] Table 1
[0036] Element C N O Content (%) 76.83 5.88 17.29
[0037] As shown in Table 1, the carbon content of the bio-derived carbon in this embodiment is 76.83%, the nitrogen content is 5.88%, and the oxygen content is 17.29%. The increase in nitrogen and oxygen content on the material surface helps to improve the wettability of the material, which provides favorable conditions for the rapid movement of ions on the material surface.
[0038] In this embodiment, 8 g, 1 g, and 1 g of seaweed-derived carbon, polyvinylidene fluoride, and carbon black were mixed in 2 mL of N-methylpyrrolidone. After magnetic stirring for 8 hours, the sample was made into a 4x4 cm 100 μm thick sheet material and dried at 60 °C for 12 hours to obtain the electrode.
[0039] Figure 2 The *Ulva prolifera* bio-derived carbon electrode of this embodiment was tested at a voltage of 0.8–1.4 V and a concentration of 100 mg / L. -1 The fluoride removal capacity of CDI in NaF solution. For example... Figure 2 , 3 As shown, the fluorine adsorption capacity of the *Ulva prolifera* bio-derived carbon electrode at 1.4V can reach 37.41 mg g. -1 This performance far surpasses that of other previously reported pure carbon materials, which fully demonstrates the potential of Ulva prolifera-derived carbon for practical application in CDI anodes.
[0040] Example 2
[0041] In this embodiment, a carbon electrode derived from Ulva prolifera is used as the anode and an activated carbon electrode is used as the cathode. A working voltage of 0.8-1.4 V is applied to achieve efficient removal of fluoride ions from water.
[0042] The Ulva prolifera-derived carbon electrode was prepared by the following method:
[0043] (1) Same as Example 1;
[0044] (2) Weigh 10g of dried seaweed powder and put it into a tube furnace. Heat it to 850℃ at 5℃ / min under a nitrogen atmosphere and hold for 1h.
[0045] (3) The above product was washed with deionized water, and after washing, it was freeze-dried at -45℃ for 30h. The dried product was then ground to obtain Ulva prolifera bio-derived carbon powder.
[0046] In this embodiment, 8 g, 1 g, and 1 g of seaweed-derived carbon, polyvinylidene fluoride, and carbon black were mixed in 2 mL of N-methylpyrrolidone. After magnetic stirring for 8 hours, the sample was made into a 4x4 cm 100 μm thick sheet material and dried at 60 °C for 12 hours to obtain the electrode.
[0047] At 1.4V, 100 mg L -1 In NaF solution, the fluorine adsorption capacity of the *Ulva prolifera* bio-derived carbon electrode in this embodiment reached 23.07 mg g. -1 ( Figure 3 ).
[0048] Example 3
[0049] In this embodiment, a carbon electrode derived from Ulva prolifera is used as the anode and an activated carbon electrode is used as the cathode. A working voltage of 0.8-1.4 V is applied to achieve efficient removal of fluoride ions from water.
[0050] The Ulva prolifera-derived carbon electrode was prepared by the following method:
[0051] (1) Same as Example 1;
[0052] (2) Weigh 10g of dried seaweed powder and put it into a tube furnace. Heat it to 750℃ at 5℃ / min under a nitrogen atmosphere and hold it for 1h.
[0053] (3) The above product was washed with deionized water, and after washing, it was freeze-dried at -45℃ for 30h. The dried product was then ground to obtain Ulva prolifera bio-derived carbon powder.
[0054] Electrode preparation is the same as in Example 1.
[0055] At 1.4V, 100 mg L -1The fluorine adsorption capacity of the Enteromorpha bio-derived carbon electrode of the embodiment in a NaF solution reaches 20.57 mg g -1 ( Figure 3 ).
[0056] Example 4
[0057] In the embodiment, the Enteromorpha bio-derived carbon electrode is used as an anode, an activated carbon electrode is used as a cathode, and a working voltage of 0.8-1.4 V is applied to achieve efficient removal of fluoride ions in water;
[0058] The Enteromorpha bio-derived carbon electrode is prepared by the following method:
[0059] (1) same as Example 1;
[0060] (2) 10 g of dry Enteromorpha powder is weighed and placed in a tube furnace, heated to 650 DEG C at 5 DEG C / min under a nitrogen atmosphere and kept for 1 h;
[0061] (3) The above product is washed with deionized water, and after washing, it is freeze-dried at-45 DEG C for 30 h. The dried product is ground to obtain Enteromorpha bio-derived carbon powder.
[0062] The electrode is prepared in the same manner as in Example 1.
[0063] 100 mg / L of fluoride ions in a NaF solution, the fluorine adsorption capacity of the Enteromorpha bio-derived carbon electrode of the embodiment reaches 23.32 mg g -1 NaF solution, the fluorine adsorption capacity of the Enteromorpha bio-derived carbon electrode of the embodiment reaches 20.57 mg g -1 ( Figure 3 ).
[0064] In summary, the present application develops an anode material with superior CDI fluorine removal performance by adjusting the preparation process of natural Enteromorpha bio-derived carbon. The raw material is low in price and easy to obtain. The self-forming of the porous structure of the material is realized by carbonization + freeze-drying. Compared with the traditional anode material preparation process, the present method has the advantages of simple reaction steps, easy batch production, and high value by-products, which greatly reduces the carbon emission in the traditional preparation method. The environment-friendly production mode significantly improves the industrialization application potential and meets the technical requirements of large-scale clean production. The Enteromorpha bio-derived carbon retains the original morphological structure of the Enteromorpha biomass, has rich pore structure and excellent pore size distribution, the average pore size can reach 8.3963 nm, the nitrogen and oxygen content on the surface of the material is rich, and the fluorine removal performance can reach 37.41 mg g -1 .
[0065] Although the specific embodiments of the present application are described in detail above, the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application, and modifications or variations not having creative labor are still within the scope of the present application.
Claims
1. A method for preparing Enteromorpha-bio-derived carbon, characterized by, The method comprises the following steps: S1, placing Enteromorpha dry powder in a nitrogen atmosphere, heating to 650-950℃, carbonizing to obtain Enteromorpha carbonized product; S2, washing the Enteromorpha carbonized product with deionized water, and freeze-drying to obtain Enteromorpha biological derivative carbon.
2. The method of producing Enteromorpha bio-derived carbon according to claim 1, characterized by: In the step S1, the heating rate is 5 ℃ / min.
3. The method of producing Enteromorpha bio-derived carbon according to claim 1, characterized by: In the step S1, the carbonization time is 1 h.
4. The method of producing Enteromorpha bio-derived carbon according to claim 1, characterized by: In the step S1, the Enteromorpha dry powder is prepared by washing fresh Enteromorpha collected from water, air-drying, crushing into powder, and passing through a 100-200 mesh screen.
5. The method of producing Enteromorpha bio-derived carbon according to claim 1, characterized by: In the step S2, the freeze-drying temperature is -45℃; the freeze-drying time is 30 h.
6. Use of the Enteromorpha biological derivative carbon prepared by the method of any one of claims 1-5 as an anode material for capacitive deionization fluoride removal.
7. An electrode for capacitive deionization fluorine removal, characterized by, The electrode is prepared by using the Enteromorpha biological derivative carbon of any one of claims 1-5, and the preparation method comprises the following steps: Enteromorpha biological derivative carbon, polyvinylidene fluoride, carbon black and N-methyl pyrrolidone are mixed in a ratio of 6-8 g: 1-3 g: 1 g: 1.4-2.0 mL, stirred, and then the mixed sample is made into a sheet material and dried to obtain the electrode.
8. The electrode for capacitive deionization fluorine removal according to claim 7, characterized by: The stirring is magnetic stirring for 7-9 hours.
9. The electrode for capacitive deionization fluorine removal according to claim 7, characterized by: The drying temperature is 60-70℃.
10. The electrode for capacitive deionization fluorine removal according to claim 7, characterized by: The drying time is 10-12 h.