Preparation method and application of bimetallic composite biochar material
By preparing nitrogen-doped bimetallic composite biochar materials and combining the micro-battery effect and Fenton-like reaction of zero-valent iron and zero-valent copper, the problem of poor dehalogenation effect of halogenated organic pollutants in the existing technology was solved, and efficient and low-cost pollutant remediation effect was achieved.
Patent Information
- Application Number
- CN202310108941.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-02-13
- Publication Date
- 2026-02-06
- Estimated Expiration
- 2043-02-13
AI Technical Summary
Existing technologies are ineffective in dehalogenating halogenated organic pollutants, especially fluorinated organic pollutants, and conventional methods are costly and inefficient, failing to meet the timeliness requirements of environmental remediation.
Nitrogen-doped bimetallic composite biochar materials were prepared by a one-step hydrothermal method. By forming zero-valent iron and zero-valent copper on the biochar, their covalent bonding and micro-battery effect were utilized to promote the reductive dehalogenation of halogenated organic pollutants and further decompose them through a Fenton-like reaction.
It achieves efficient degradation of halogenated organic pollutants, especially fluorinated organics, with significant degradation effect. Moreover, the material preparation is simple and low-cost, requiring no external chemical agents, avoiding zero-valent metal agglomeration, and improving reactivity.
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Figure CN116395816B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to a preparation method of a bimetallic composite biochar material for halogenated organic pollutant degradation and application thereof, and belongs to the technical field of environmental organic pollution remediation. BACKGROUND
[0002] For a long time, due to the large-scale production of halogenated organics such as pesticides, dyes, polychlorinated biphenyls and antibiotics and their wide use in industry and agriculture, the universal residues and frequent detections of these chemicals in the natural environment have caused potential harm to the ecological environment and human health, which has attracted widespread attention.
[0003] At present, there are many reports on the degradation and removal technology of halogenated organic pollutants, such as zero-valent iron material reduction, advanced oxidation, thermal treatment, adsorption, microbial technology and the like. Among them, the advanced oxidation, thermal treatment and adsorption technology have the advantages of good universality, mature process and the like, but the dehalogenation reaction of halogenated organic pollutants by using the advanced oxidation technology usually needs to be carried out under relatively extreme conditions; the thermal treatment technology needs to consume a large amount of energy; and the adsorption technology only realizes the transfer of pollutants, and needs to update or replace the adsorbent, which is high in cost and easy to cause secondary pollution. In comparison, the microbial technology is an environmentally friendly and low-cost treatment technology, but in the application process, it is often limited and affected by factors such as complex environmental factors, microbial competition and long repair time, and cannot meet the timeliness requirements of current environmental remediation.
[0004] Zero-valent iron is a kind of excellent reduction material, which is simple and easy to obtain, and has been widely concerned and deeply researched in the field of halogenated organic pollutant degradation. In addition, zero-valent iron will have a corrosion reaction in water, and the corrosion products formed by the corrosion reaction have good adsorption performance, and the dissolved iron ions have flocculation effect, so they have multiple beneficial effects on halogenated organic pollutants. However, although many studies have shown that zero-valent iron has good dechlorination effect on chlorinated organic matter, the dehalogenation and degradation effect on fluorinated, brominated and iodinated organic matter is not satisfactory, especially fluorinated organic matter, because the carbon-fluorine bond is the strongest chemical bond known in organic chemistry, and it is difficult to be polarized, so it is difficult to remove fluorine atoms in the form of anions or free radicals. Therefore, developing a repair material and related repair technology with good dehalogenation effect, wide application range and low cost is the key to realizing the rapid and efficient remediation of halogenated organic pollutants in the environmental medium. SUMMARY
[0005] The technical problem to be solved by the present application is to provide a preparation method of a bimetallic composite biochar material capable of improving the dehalogenation efficiency of single zero-valent iron technology.
[0006] In order to solve the above problems, the technical scheme provided by the present application is as follows:
[0007] The application discloses a preparation method of a bimetallic composite biochar material.
[0008] Step 1): iron salt and copper salt are dissolved in deionized water, ammonia water is added and uniformly mixed, then biomass raw materials are soaked, and magnetic stirring is carried out at room temperature to obtain a solid mixture.
[0009] Step 2): the solid mixture obtained in step 1) is ground into a uniform powder with a mortar, the powder is placed in a stainless steel hydrothermal reaction kettle for reaction to form a hydrothermal solid product, and the hydrothermal solid product is washed, filtered and dried to obtain the bimetallic composite biochar material.
[0010] Preferably, the iron salt in step 1) is at least one of ferric chloride, ferric sulfate, ferric nitrate and ferric citrate, and the copper salt is at least one of cupric chloride, cupric sulfate, cupric nitrate and cupric citrate.
[0011] Preferably, the mass ratio of iron elements in the iron salt to the biomass raw materials in step 1) is (0.1-0.5):1, the atomic molar ratio of copper elements in the copper salt to iron elements in the iron salt is (0.2-1):1, and the atomic molar ratio of nitrogen elements in the ammonia water to iron elements in the iron salt is (1-3):1.
[0012] Preferably, the biomass raw materials in step 1) are cellulose or lignin.
[0013] Preferably, the magnetic stirring rate in step 1) is 400-800 r / min.
[0014] Preferably, the temperature of the stainless steel hydrothermal reaction kettle in step 2) is 240-300 DEG C, the temperature rising rate is 5-15 DEG C / min, and the reaction time is 4-8 h.
[0015] Preferably, in step 2), 100% ethanol and ultrapure water are used for washing, and the washing mode is alternating washing for 3-5 times.
[0016] The application further provides application of the preparation method of the bimetallic composite biochar material to remediation of halogenated organic pollutants in wastewater and contaminated soil.
[0017] The application takes nitrogen-doped biochar as a carrier, forms zero-valent iron and zero-valent copper bimetallic composite materials through a hydrothermal reaction, has excellent dehalogenation performance and organic pollutant degradation capacity, and has the advantages of simple material preparation method, mild reaction process and low preparation cost. In the hydrothermal process, high-valence iron and copper ions are reduced to form zero-valent iron and zero-valent copper on the biochar, and nitrogen elements are converted into pyrrole nitrogen and pyridine nitrogen and embedded into the graphitized biochar material. Since nitrogen and iron / copper metal can form stable covalent bonds, the zero-valent iron and zero-valent copper can be firmly combined with the biochar, and the zero-valent metal is uniformly dispersed and has good stability. The potential difference between the zero-valent iron and the zero-valent copper is high, and has excellent interface electron migration capacity, which can effectively reduce and dehalogenate halogenated organic pollutants, and through the synergistic effect, a Fenton-like reaction is triggered to generate active oxygen substances with strong oxidation, thereby realizing the further decomposition and mineralization of halogenated organic pollutants.
[0018] Compared with the prior art, the application has the following beneficial effects:
[0019] (1) The bimetallic composite biochar material provided by the application has more excellent dehalogenation performance than single zero-valent iron, and also has good defluorination effect on fluorinated organic pollutants, thereby providing a new idea and method for the effective remediation of halogenated organic pollutants in the environment medium.
[0020] (2) The bimetallic composite biochar material provided by the application can also trigger a Fenton-like reaction during the remediation process to generate a large amount of active oxygen substances with strong oxidation, which can effectively promote the further degradation and mineralization of dehalogenation by-products.
[0021] (3) Compared with the conventional advanced oxidation technology based on iron-based materials, which needs to add chemical reagents, the application does not need to add other chemical reagents, and the micro-battery effect formed by the zero-valent iron and the zero-valent copper in the composite biochar material can promote the interface electron transfer, improve the reaction activity, and strengthen the dehalogenation effect on halogenated organic pollutants.
[0022] (4) The bimetallic composite biochar material provided by the application is synthesized by one-step hydrothermal method, which synchronously completes the carbonization of biomass and the reduction process of high-valence iron / copper raw materials to generate zero-valent elements, effectively avoids the problem of zero-valent metal agglomeration in the traditional reduction method, and promotes the degradation effect of halogenated organic pollutants. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 The flow chart of the preparation method of the bimetallic composite biochar material provided by the application;
[0024] Figure 2 The data graph of the removal effect of florfenicol antibiotic and the defluorination and dechlorination effects in Example 1;
[0025] Figure 3 Data graph for removal effect of p-chlorophenol in Example 2;
[0026] Figure 4 Data graph for dechlorination effect of p-chlorophenol in Example 2. DETAILED DESCRIPTION
[0027] In order to make the present application more apparent and easy to understand, the preferred embodiments are described in detail below with reference to the accompanying drawings.
[0028] Example 1
[0029] 6.5 g of FeCl3·6H2O and 1.5 g of CuCl2·2H2O were dissolved in 40 mL of deionized water, 5 mL of ammonia water was added and uniformly mixed, and then 7.5 g of microcrystalline cellulose was added. The mixture was stirred at room temperature at a speed of 450 r / min, and after being stirred to be substantially dry, it was left to stand for 24 h to obtain a solid mixture. Subsequently, the obtained solid mixture was ground into a uniform powder using a maroon mortar, and then was placed in a stainless steel hydrothermal reactor, which was heated to 240℃ at a heating rate of 10℃ / min and maintained for 4 h. After the reaction was completed, the hydrothermal solid product was naturally cooled, washed with 100% ethanol and ultrapure water alternately for 3 times to remove the residual inorganic substances and the attached tar-like organic by-products on the surface, and then was filtered and freeze-dried to obtain the bimetallic composite biochar material.
[0030] In order to investigate the dehalogenation performance of the bimetallic composite biochar material of the present application on halogenated organic pollutants, florfenicol antibiotic containing chlorine and fluorine atoms was taken as the target object, and the bimetallic composite biochar material synthesized above was added into 40 mL of florfenicol solution with a concentration of 100 mg / L, and the bimetallic composite biochar material was added at a concentration of 1 g / L. The change of the florfenicol removal rate with the reaction time is shown in Figure 2 It can be seen that after 24 h of reaction under neutral conditions, the florfenicol removal rate can reach 95.1%, but the defluorination rate and the dechlorination rate are still relatively low. However, after 15 days of reaction, the defluorination rate and the dechlorination rate of the bimetallic composite biochar material on florfenicol can reach 73.2% and 82.1% respectively, and the florfenicol removal rate can reach 99.6%, which indicates that the bimetallic composite biochar material of the present application has very good removal effect on florfenicol antibiotic under neutral conditions, and the defluorination and dechlorination effects are obvious.
[0031] Example 2
[0032] 9.7 g of Fe(NO3)3·9H2O and 4.3 g of Cu(NO3)2·3H2O were dissolved in 60 mL of ultrapure water, then 5 mL of ammonia water was added and mixed uniformly, 10 g of lignocellulose was added, and magnetic stirring was carried out at room temperature at a stirring speed of 600 r / min. After stirring to dryness, the mixture was allowed to stand for 24 h to obtain a solid mixture. Subsequently, the obtained solid mixture was ground into a uniform powder using a marble mortar, and then placed in a stainless steel hydrothermal reactor, and heated to 300℃ at a heating rate of 5℃ / min and maintained for 8 h. After the reaction was completed, the mixture was allowed to cool naturally, and the obtained hydrothermal solid product was washed with 100% ethanol and ultrapure water alternately for 5 times to remove the residual inorganic substances and the attached tar-like organic by-products on the surface, and then filtered and freeze-dried to obtain the bimetallic composite biochar material.
[0033] With p-chlorophenol as the target object, the bimetallic composite biochar material synthesized above was added to 40 mL of a p-chlorophenol solution with a concentration of 100 mg / L, and the bimetallic composite biochar material was added at a concentration of 1 g / L. The removal rate of p-chlorophenol with the change of reaction time is shown in Figure 3 It can be seen that after 8 h of reaction under neutral conditions, the removal rate of p-chlorophenol can reach 94.7%; and when the reaction continues to 48 h, the dechlorination rate of the bimetallic composite biochar material to p-chlorophenol can reach 93.1% (100 mg / L of p-chlorophenol 100% dechlorination, the theoretical concentration of chloride ions is 27.5 mg / L) Figure 4 ), and the removal rate of p-chlorophenol is 100%, indicating that the bimetallic composite biochar material of the present application also has very good removal effect on p-chlorophenol under neutral conditions, and the dechlorination effect is significant.
Claims
1. A method of preparing a bimetallic composite biochar material, characterized by, The method comprises the following steps: Step 1): dissolving iron salt and copper salt in deionized water, adding ammonia water and mixing uniformly, then adding biomass raw material for soaking, and obtaining a solid mixture under magnetic stirring at room temperature; the iron salt is at least one of ferric chloride, ferric sulfate, ferric nitrate and ferric citrate, the copper salt is at least one of copper chloride, copper sulfate, copper nitrate and copper citrate; the biomass raw material is cellulose or lignin; the mass ratio of iron element in the iron salt to the biomass raw material is (0.1-0.5):1, the atomic molar ratio of copper element in the copper salt to iron element in the iron salt is (0.2-1):1, and the atomic molar ratio of nitrogen element in the ammonia water to iron element in the iron salt is (1-3):1; Step 2): grinding the solid mixture obtained in step 1) into a uniform powder with a mortar, and then putting the powder into a stainless steel hydrothermal reaction kettle for reaction to form a hydrothermal solid product; the temperature of the stainless steel hydrothermal reaction kettle is 240-300 DEG C, the heating rate is 5-15 DEG C / min, the reaction time is 4-8 h, and then the product is washed, filtered and dried to obtain the bimetallic composite biochar material.
2. The method of claim 1, wherein the bimetallic composite biochar material is prepared by the steps of: The magnetic stirring rate in step 1) is 400-800 r / min.
3. The method for preparing the bimetallic composite biochar material as described in claim 1, characterized in that, In step 2), 100% ethanol and ultrapure water are used for washing, and the washing mode is alternating washing for 3-5 times.
4. Application of the preparation method of the bimetallic composite biochar material in any one of claims 1-3 in the remediation of halogenated organic pollutants in wastewater and contaminated soil.