Modified biomass charcoal as well as preparation method and application thereof
By microwave oxidation modification and chemical modification of bagasse biomass charcoal, modified biomass charcoal was prepared, which solved the problem of insufficient phosphorus supply in forest soil, improved the soil carbon and phosphorus level, and achieved more efficient phosphorus utilization and soil Improved effect.
Patent Information
- Application Number
- CN202411550963.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2025-02-11
AI Technical Summary
The effective supply capacity of phosphorus in forest soil is low, which limits plant growth. The cost of traditional fertilizer application and low utilization rate makes it difficult to increase the soil carbon and phosphorus level.
Modified bagasse biomass charcoal by microwave oxidation and chemically reacting with organosilane in organic solvents, modified biomass charcoal is prepared, increasing the amino/methoxy functional groups on its surface, and improving soil ion chelation and The ability of phosphate ions to release.
It significantly improves the carbon and phosphorus level of soil, promotes the effective utilization of phosphorus, improves the ecological environment of the soil, and reduces the cost of fertilizer application and environmental pollution.
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Figure CN119410375A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of soil improvement, and in particular relates to a modified biochar and a preparation method and application thereof. Background Art
[0002] As the main body of terrestrial ecosystems, forest ecosystems are rich in biodiversity and have high ecosystem service value, such as annual carbon sequestration equivalent to 25% of annual emissions, providing wood production, protecting water resources, and carrying out material decomposition and nutrient supply. However, in the past few decades, in order to increase the global supply of wood and land resources, many forests have been cut down, and the area of natural forests has decreased sharply. Continuous cutting has led to serious soil erosion, land degradation, loss of biodiversity, and increased the emission of carbon dioxide from the soil to the atmosphere. In response to this change, people have restored vegetation productivity and increased the carbon sink function of terrestrial ecosystems through measures such as returning farmland to forests and afforestation. However, the nutrient resources of forest soils are poor, especially in the southern region. The available phosphorus in the soil is easily adsorbed by iron and aluminum ions and forms insoluble bound phosphorus, resulting in low soil effective phosphorus supply capacity, which restricts plant growth, and with the increase of forest age, phosphorus limitation becomes more and more serious. The increase in organic carbon content can provide the energy and carbon source required by microorganisms, accelerate the turnover of soil microorganisms, and provide more effective phosphorus to meet plant growth. At the same time, the effectiveness of soil phosphorus promotes the mineralization of microbial carbon sources. Therefore, the carbon and phosphorus cycles are interactive and closely linked.
[0003] In plantation management, more phosphorus is provided to plants by applying chemical fertilizers. This method is costly and has a low utilization rate of phosphorus fertilizers. Nearly half of the phosphorus fertilizers cannot be used and easily enter the ecosystem, causing non-point source pollution. Therefore, it is extremely urgent to improve the quality and efficiency of artificial phosphorus and increase carbon sequestration.
[0004] Guangxi is the largest sugarcane production base in my country, and its sugarcane sales account for about 80% of the country's inter-provincial trade volume. A large amount of organic waste, namely bagasse biochar, is generated during the sugarcane production process. In 2022, Guangxi's sugarcane production was about 15 million tons, and bagasse accounted for about 25% of the total production. Only 20% of the bagasse was used for man-made fiberboard, pulp and paper, and feed, and about 80% was not used reasonably and efficiently. Therefore, how to use bagasse to improve soil carbon and phosphorus levels is a difficult problem that needs to be solved urgently in this field. Summary of the invention
[0005] The purpose of the present invention is to provide a modified biochar and a preparation method and application thereof to solve the problems existing in the above-mentioned prior art.
[0006] One of the technical solutions provided by the present invention:
[0007] A method for preparing modified biochar comprises the following steps: subjecting bagasse biochar to microwave treatment to obtain microwave oxidized modified biochar, dispersing the microwave oxidized modified biochar and organosilane in an organic solvent, adding a promoter to the obtained suspension, heating for reaction, cooling to room temperature, centrifuging, washing, and freeze-drying to prepare the modified biochar.
[0008] Biochar has good dielectric properties and microwave absorption properties. Through microwave heating treatment, it can quickly release Joule heat in an ultra-short time, significantly increase the temperature of biomass, and achieve rapid oxidation in an air atmosphere, which effectively increases the number of oxygen-containing functional groups in biochar. A large number of oxygen-containing functional groups react chemically with organosilicon in organic solvents, increasing the number of amino / methoxy organic functional groups on the surface of biochar.
[0009] Preferably, the bagasse biochar is prepared by subjecting bagasse to a cracking reaction at 600° C. for 1 h.
[0010] Preferably, the power of the microwave treatment is 500-800W; the time of the microwave heating is 20-60s.
[0011] Preferably, the usage ratio of the microwave oxidation modified biochar and the organosilane is (2-4) g: (3-4) mL.
[0012] More preferably, the organosilane is aminopropyltrimethoxysilane or aminopropyltripropoxysilane.
[0013] Preferably, the heating reaction is carried out at a temperature of 100-120° C. and for a time of 2-3 hours.
[0014] The second technical solution provided by the present invention is:
[0015] A modified biochar is prepared by the above preparation method.
[0016] The third technical solution provided by the present invention is:
[0017] An application of the modified biochar in improving soil carbon and phosphorus levels.
[0018] Preferably, the modified biochar is applied to the soil at 5-20 t / ha.
[0019] More preferably, the modified biochar is applied to the soil at 5 t / ha.
[0020] Compared with the prior art, the present invention has the following advantages and technical effects:
[0021] The present invention treats bagasse biochar with microwaves and combines it with amino grafting modification to increase the number of amino / methoxy organic functional groups on the surface of bagasse biochar, thereby increasing the ability to absorb Al in the soil.3+ , Fe 3+ and Ca 2+ Ion chelation promotes the release of phosphate ions, thereby increasing soil carbon and phosphorus levels. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0023] Figure 1 Schematic diagram of the effect of modified biochar addition concentration and time on soil phosphorus components in Application Example 1 (Karst soil) and Application Example 2 (non-Karst soil), where a and b are Citrate-P content, c and d are HCl-P content, e and f are Enzyme-P content, and g and h are MBP content;
[0024] Figure 2 Schematic diagram of the effect of modified biochar addition concentration and time on soil phosphorus components (Olsen-P) in Application Example 1 (Karst soil) and Application Example 2 (non-Karst soil). DETAILED DESCRIPTION
[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0026] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.
[0027] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.
[0028] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.
[0029] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.
[0030] The room temperature in the present invention refers to 25±2°C.
[0031] In addition, unless otherwise specified, % in Examples and Comparative Examples is based on mass.
[0032] The chemical reagents required in the embodiments of the present invention are all purchased from commercial sources.
[0033] Example 1 A method for preparing modified biochar
[0034] S1. Remove impurities such as stones from bagasse, crush it into 0.5-1.5 cm in length by a crusher, dry the crushed material (70°C, 40 min) to obtain bagasse with a moisture content of 12%; carbonize the obtained bagasse (600°C, 1 h), and pulverize the carbonized product to prepare bagasse biomass charcoal;
[0035] S2. The bagasse biochar was placed in a microwave heating reactor, under an air atmosphere, the power was adjusted to 500 W, and microwave-heated for 60 s under an air atmosphere, and then cooled to obtain microwave-oxidized modified biochar;
[0036] S3. Accurately weigh 20 g of microwave oxidized modified biochar, take 40 mL of aminopropyltrimethoxysilane and disperse it in toluene. After mixing, a suspension is obtained, 0.1 mL of promoter (triethylamine) is added, and then heated to react (100°C, 3h). After the reaction is completed, cool to room temperature, centrifuge to remove toluene, rinse with acetone 5 times, centrifuge, and finally freeze-dry to obtain modified biochar.
[0037] Example 2
[0038] S1. removing impurities such as stones from bagasse, crushing it into 0.5-1.5 cm in length through a crusher, drying the crushed material (80°C, 20 min) to obtain bagasse with a moisture content of 10%; carbonizing the obtained bagasse (600°C, 1 h), and pulverizing the carbonized product to prepare bagasse biomass charcoal;
[0039] S2. The bagasse biochar was placed in a microwave heating reactor, under an air atmosphere, the power was adjusted to 800 W, and microwave-heated for 25 s under an air atmosphere, and then cooled to obtain microwave-oxidized modified biochar;
[0040] S3. Accurately weigh 4 g of microwave-oxidized modified biochar, take 3 mL of aminopropyltripropoxysilane and disperse it in toluene. After mixing, a suspension is obtained, 0.1 mL of promoter (triethylamine) is added, and then heated to react (100°C, 3 h). After the reaction is completed, cool to room temperature, centrifuge to remove toluene, rinse with acetone 5 times, centrifuge, and finally freeze-dry to obtain modified biochar.
[0041] Comparative Example 1
[0042] S1. removing impurities such as stones from bagasse, crushing it into 0.5-1.5 cm in length through a crusher, drying the crushed material (70°C, 40 min) to obtain bagasse with a moisture content of 12%; carbonizing the obtained bagasse (600°C, 1 h), and pulverizing the carbonized product to prepare bagasse biomass charcoal;
[0043] S2. Accurately weigh 20 g of bagasse biochar, take 40 mL of aminopropyltrimethoxysilane and disperse it in toluene. After mixing, a suspension is obtained, 0.1 mL of promoter (triethylamine) is added, and then heated to react (100°C, 3h). After the reaction is completed, cool to room temperature, centrifuge to remove toluene, rinse with acetone 5 times, centrifuge, and finally freeze-dry to obtain modified biochar.
[0044] Application Example 1
[0045] Four 20m×20m sample plots were randomly set in the karst soil, and the distance between each sample plot was greater than 10m. Ten soil samples were collected from the 0-5cm surface soil of each sample plot, and four samples were obtained after mixing evenly. Then, the samples were put into ziplock bags and taken back to the laboratory. The collected soil was sieved in the laboratory to remove impurities, and the culture experiment was arranged to add 4 modified biochar treatments (W / W) prepared in Example 1: the addition amount was 0t / ha (recorded as C0), 5t / ha (recorded as C1), 10t / ha (recorded as C2), and 20t / ha (recorded as C3). Each treatment was repeated 4 times. 100 g of fresh soil was fully mixed with modified biochar and placed in a 500 mL brown culture bottle. The soil moisture content was 60% of the field water holding capacity. All culture bottles were cultured at 25°C in the dark for 80 days. Soil samples were collected at 7, 20, 40, and 80 days to determine related indicators such as phosphorus components, microbial biomass, and enzyme activity.
[0046] Application Example 2
[0047] Four 20m×20m sample plots were randomly set in the soil of non-karst areas, and the distance between each sample plot was greater than 10m. Ten soil samples were collected from the 0-5cm surface soil of each sample plot, and four samples were obtained after being mixed evenly. Then, the samples were put into self-sealing bags and taken back to the laboratory. The collected soil was sieved in the laboratory to remove impurities, and the culture experiment was arranged to add 4 modified biochar treatments prepared in Example 2 (W / W): the addition amount was 0t / ha (recorded as C0), 5t / ha (recorded as C1), 10t / ha (recorded as C2), and 20t / ha (recorded as C3). Each treatment was repeated 4 times. 100 g of fresh soil was fully mixed with modified biochar and placed in a 500 mL brown culture bottle. The soil moisture content was 60% of the field water holding capacity. All culture bottles were cultured at 25°C in the dark for 80 days. Soil samples were collected at 7, 20, 40, and 80 days to determine related indicators such as phosphorus components, microbial biomass, and enzyme activity.
[0048] Soil phosphorus component determination method: Soil total phosphorus (TP) was added with NaOH and then placed in a muffle furnace for high temperature digestion. 2 SO 4 +HCl, then developed with molybdenum blue colorimetric solution and measured with a spectrophotometer; soil available phosphorus (Olsen-P) was measured with NaHCO 3 After solution extraction, the color development and determination steps were the same as those for TP; microbial biomass phosphorus (MBP) was determined by chloroform fumigation and NaHCO 3 The solution was extracted and then determined by molybdenum antimony colorimetric-ultraviolet spectrophotometry. Weigh 0.5g of fresh soil into a 15mL centrifuge tube, then add 10mL of the extract and place it at 25℃ constant temperature for 3h (180r·min-1 ), and the supernatant was extracted by centrifugation. The extracts of citric acid-extracted phosphorus (Citrate-P) and hydrochloric acid-extracted phosphorus (HCl-P) were 10 mmol·L -1 Citric acid, 1 mol·L -1 Hydrochloric acid. The extract of enzyme-P is 0.02EUmL -1 Enzymes, including acid phosphatase, alkaline phosphatase and phytase, the concentration of all three enzymes was 0.02EU·mL -1 .
[0049] Figure 1 Schematic diagram of the effect of modified biochar addition concentration and time on soil phosphorus components (HCl-P (soil available phosphorus), Citrate-P (soluble phosphorus), Enzyme-P (enzyme-extractable phosphorus), MBP (microbial biomass phosphorus)) in Application Example 1 (Karst soil) and Application Example 2 (non-Karst soil). Figure 1 It can be seen that: at the same cultivation time, compared with the blank control, the addition of biochar significantly increased the Citrate-P (a and b) and HCl-P contents (c and d) in the soil; among them, at the same concentration of added biochar, the maximum Citrate-P content in the soil appeared on the 7th day of cultivation, and the minimum appeared on the 80th day of cultivation; the maximum HCl-P content appeared on the 20th day of cultivation. At the same cultivation time, compared with the blank control, the addition of biochar at 40d and 80d significantly increased the Enzyme-P content (e); at the same cultivation time, compared with the blank control, at a concentration of 5t / ha, in the karst area soil, the addition of biochar at 7, 20, 40d and 80d significantly increased the MBP content.
[0050] Figure 2 Schematic diagram of the effect of modified biochar addition concentration and time on soil phosphorus components (Olsen-P) in Application Example 1 (Karst soil) and Application Example 2 (non-Karst soil). Figure 2 It can be seen that compared with the blank control, whether it is Karst soil or non-Karst soil, after the same concentration of biochar is added, the Olsen-P content increases with time.
[0051] Based on the overall experimental data and economic considerations, in order to improve the carbon and phosphorus levels in the soil in the karst area, the present invention selects modified biochar and applies it to the soil at a rate of 5-ha.
[0052] Application Example 3
[0053] Four 20m×20m sample plots were randomly set up in the soil of the karst area, and the distance between each sample plot was greater than 10m. Ten soil samples were collected from the 0-5cm surface soil of each sample plot, and four samples were obtained after mixing evenly. Then they were put into self-sealing bags and taken back to the laboratory. The collected soil was sieved in the laboratory to remove impurities. The culture experiment was arranged with four treatments (W / W) with the modified biochar prepared in comparative example 1: the addition amount was 0t / ha (denoted as C0) and 5t / ha (denoted as C1). Each treatment was repeated 4 times. 100g of fresh soil was fully mixed with the modified biochar and placed in a 500mL brown culture bottle. The soil moisture content was 60% of the field water holding capacity. All culture bottles were placed in 25℃ dark conditions for 80d. Soil samples were collected at 7, 20, 40, and 80d of culture, respectively, to determine relevant indicators such as phosphorus components, microbial biomass, and enzyme activity.
[0054] The method for determining the soil phosphorus component in Application Example 3 is the same as that in Application Example 1. In Application Example 3, since the modified biochar used was not microwave-modified during the preparation process, the adsorption performance of the prepared modified biochar was significantly reduced. The measurement results showed that compared with the modified biochar prepared in Example 1 applied at 5t / ha in Application Example 1, the Olsen-P, HCl-P, Citrate-P, Enzyme-P and MBP contents measured at the same time decreased by 10-15wt.%, respectively.
[0055] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A method for preparing modified biochar, characterized in that: The microwave-oxidized modified biochar is obtained by microwave-treating bagasse biochar, the microwave-oxidized modified biochar and organosilane are dispersed in an organic solvent, a promoter is added to the obtained suspension, the suspension is heated for reaction, cooled to room temperature, centrifuged, washed, and freeze-dried to prepare the modified biochar.
2. The method for preparing modified biochar according to claim 1, characterized in that: The bagasse biochar is prepared by subjecting bagasse to a cracking reaction at 600° C. for 1 h.
3. The method for preparing modified biochar according to claim 1, characterized in that: The power of the microwave treatment is 500-800W; the time of the microwave heating is 20-60s.
4. The method for preparing modified biochar according to claim 1, characterized in that: The usage ratio of the microwave oxidation modified biochar and the organosilane is (2-4) g: (3-4) mL.
5. The method for preparing modified biochar according to claim 4, characterized in that: The organosilane is aminopropyltrimethoxysilane or aminopropyltripropoxysilane.
6. The method for preparing modified biochar according to claim 1, characterized in that: The heating reaction temperature is 100-120° C. and the time is 2-3 hours.
7. A modified biochar, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 6.
8. Use of the modified biochar according to claim 7 in improving soil carbon and phosphorus levels.
9. The use according to claim 8, characterized in that: The modified biochar is applied to the soil at 5-20 t / ha.
10. The use according to claim 9, characterized in that: The modified biochar was applied to the soil at 5 t / ha.