Composite rice husk carbon for improving soil and carbon sequestration and sink increase method
By calcining rice husk charcoal with calcium bicarbonate and alkali treatment, a composite rice husk charcoal was prepared, which solved the problem of insufficient salt-alkali soil improvement and carbon sequestration improvement technology, and achieved the improvement of soil carbon density and plant Improvement of growth environment.
Patent Information
- Application Number
- CN202411514044.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-02-07
AI Technical Summary
There are insufficient technologies for improving saline-alkali soils and sequestration and increase carbon sinks, which is difficult to effectively improve soil carbon density and plant growth environment.
By mixing the rice husk charcoal with calcium bicarbonate and calcining, calcified rice husk charcoal is formed and alkaline treatment is performed to prepare carbon-sinkage-enhancing composite rice husk charcoal. The composite rice husk charcoal is mixed with the soil at a specific volume ratio and replaced with a soil layer of no less than 40cm thick to improve the soil structure and carbon sequestration capacity.
It improves the soil carbon density, reduces carbon escape, improves the fertility of saline-alkali soil and plant growth environment, and has a significant carbon sequestration and increase sink effect.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the field of soil improvement, and in particular relates to a composite rice husk charcoal for improving soil and a carbon fixation and sink enhancement method. Background Art
[0002] The soil carbon pool is the largest carbon pool in terrestrial ecosystems. Its reserves far exceed those of the atmosphere and vegetation carbon pools, and it is also an important part of the global carbon cycle. Soil carbon reserves are of great significance in global climate change. Soil not only absorbs and stores CO2 as a carbon sink, reducing the concentration of CO2 in the atmosphere, but also has a positive feedback mechanism for climate change. Rising temperatures will accelerate the decomposition of organic carbon in the soil, releasing more CO2 into the atmosphere. According to research by Chen Wenfu, an academician of the Chinese Academy of Engineering, when rice husk charcoal is burned or rotted, the carbon in it will be released into the atmosphere in the form of carbon dioxide; if it is returned to the field, it will basically be fixed in the soil, which can play a role in carbon sequestration. Soil carbon sinks include organic and inorganic carbon sinks. The former refers to the decomposition and conversion of plant organic matter into organic carbon in the soil, and the latter refers to the conversion of atmospheric CO2 into primary or secondary minerals in the soil. According to incomplete statistics from UNESCO and the Food and Agriculture Organization, the area of saline-alkali land in the world is about 954 million hm2. 2 As a special difficult land, saline-alkali soil has great utilization value and carbon storage potential. It is of great practical significance to explore new ways to use rice husk charcoal in saline soil improvement and explore its carbon sequestration and sink function. Summary of the invention
[0003] The present invention mainly provides a composite rice husk charcoal for improving soil. The technical scheme is as follows:
[0004] A composite rice husk charcoal for improving soil, the preparation method comprising the following steps: using rice husks to prepare rice husk charcoal, then mixing the rice husk charcoal with calcium bicarbonate, and then calcining to obtain calcified rice husk charcoal; and subjecting the calcified rice husk charcoal to alkali treatment to obtain a composite rice husk charcoal for fixing carbon and enhancing carbon sink.
[0005] Furthermore, the preparation of the carbon fixation and sink-enhancing composite rice husk charcoal comprises the following steps:
[0006] a. Freezing the rice husk charcoal with water to obtain ice-containing rice husk charcoal;
[0007] b. Take out the ice-containing rice husk charcoal and let it stand until water droplets appear on the surface and flow down, then add calcium bicarbonate, mix and grind for 1 to 2 hours, then calcine at 400 to 550 ° C for 1 to 2 hours, and naturally cool to room temperature to obtain calcified rice husk charcoal;
[0008] c. Disperse ethylenediaminetetraacetic acid in a sodium hydroxide solution with a pH of 10 to 13 to obtain a complexing solution; fully disperse the calcified rice husk charcoal in cold water, and inject carbon dioxide into it until the pH no longer changes, then add the complexing solution, mix and stir until the pH of the system no longer changes, and evaporate the solvent to obtain composite rice husk charcoal.
[0009] Furthermore, the freezing treatment in step a is to immerse the rice husk charcoal in water, expel the gas, and then freeze it to a central temperature below -18°C.
[0010] Furthermore, the mass ratio of the calcium bicarbonate to the ice-containing rice husk charcoal in step b is 1:10-20.
[0011] Furthermore, in step c, the mass ratio of EDTA to calcified rice husk charcoal is 1:10-20;
[0012] Furthermore, the cold water in step c is water at 0-8°C.
[0013] Furthermore, the preparation of the rice husk charcoal includes the following steps: crushing the rice husk, and then drying it below 120°C until the volume no longer decreases to obtain rice husk powder; heating the rice husk powder to 450-550°C at a heating rate of 100°C / h, naturally cooling it to 350-450°C and maintaining it for 0.5-1h, and naturally cooling it to room temperature to obtain rice husk charcoal.
[0014] Furthermore, the rice husk is crushed to a D90 of less than 5 mm.
[0015] A method for carbon fixation and sink enhancement using the above-mentioned composite rice husk charcoal for improving soil, characterized in that the composite rice husk charcoal is mixed with soil in a volume ratio of 1:2.3 to 18, and then a soil layer of not less than 40 cm thick is replaced.
[0016] Furthermore, the composite rice husk charcoal was mixed with soil in a volume ratio of 1:9.
[0017] By adopting the above scheme, the method of the present invention has the following advantages:
[0018] 1. The rice husk charcoal of the present invention contains a large amount of silicon, which is partially ionized to form sodium silicate after alkali treatment, which is beneficial to improving the photosynthesis and chlorophyll content of crops, making the stems and leaves straight, promoting the accumulation of organic matter, and can synergize with sodium to enhance the formation of stable carbon sinks and reduce soil carbon escape.
[0019] 2. When preparing rice husk charcoal in the present invention, high temperature is first used to promote the porosity of the rice husk charcoal to improve the carbon fixation and sink capacity, and then low temperature is used to make the carbonization more thorough and uniform to reduce the generation of by-products.
[0020] 3. The present invention freezes the rice husk charcoal and then grinds it together with calcium bicarbonate. During the grinding process, the rice husk charcoal and the calcium bicarbonate are fully mixed and refined together, while avoiding the decomposition of the calcium bicarbonate. The calcium bicarbonate is then quickly decomposed by heating to generate gas, thereby increasing the porosity of the rice husk charcoal.
[0021] 4. The present invention uses calcium bicarbonate and rice husk charcoal for treatment, and calcium is added to the rice husk charcoal to complex with ethylenediaminetetraacetic acid, so that the ethylenediaminetetraacetic acid penetrates into the rice husk charcoal, thereby enriching nitrogen in the rice husk charcoal, avoiding calcium, nitrogen, etc. from being exposed on the surface of the rice husk, causing drastic changes in soil elements.
[0022] 5. The nitrogen of the present invention is enriched in the rice husk charcoal, which is beneficial to the growth of plants and microorganisms, and facilitates the fungi and actinomycetes in the soil to mechanically entangle the soil and the rice husk charcoal with hyphae to form aggregates, thereby promoting the fixation of soil organic matter.
[0023] 6. The composite rice husk charcoal for improving soil of the present invention is used for carbon fixation and sink enhancement, which can effectively increase the carbon density of soil in each soil layer, release a small amount of carbon, accumulate and store a large amount of carbon, and can effectively improve the soil fertility of saline-alkali land and promote plant growth.
[0024] 7. The present invention can effectively reduce soil salt content and density, increase organic matter content, effectively improve saline soil, improve tree survival rate and growth, and promote the growth of young forests. DETAILED DESCRIPTION
[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0026] Embodiment 1:
[0027] (1) crushing rice husks to a D90 of less than 5 mm, and then drying at below 120° C. until the volume no longer decreases, thereby obtaining rice husk powder; heating the rice husk powder to 500° C. at a heating rate of 100° C. / h, naturally cooling the rice husk powder to 400° C. and maintaining the temperature for 0.5 to 1 h, and then naturally cooling the temperature to room temperature to obtain rice husk charcoal;
[0028] (2) immersing the rice husk charcoal in water, exhausting the gas, and freezing it until the center temperature is below -18°C to obtain ice-containing rice husk charcoal;
[0029] (3) The ice-containing rice husk charcoal is taken out and allowed to stand until water droplets are generated on the surface and converge and flow down, and then 0.1 times the mass of calcium bicarbonate of the ice-containing rice husk charcoal is added, mixed and ground for 1 hour, and then calcined at 500°C for 1 hour, and naturally cooled to room temperature to obtain calcified rice husk charcoal;
[0030] (4) dispersing ethylenediaminetetraacetic acid in a sodium hydroxide solution with a pH of 12 to obtain a complexing solution; fully dispersing calcified rice husk charcoal with a mass 10 times that of ethylenediaminetetraacetic acid in water at 2 to 6° C., injecting carbon dioxide into the water until the pH no longer changes, then adding the complexing solution, mixing and stirring until the pH of the system no longer changes, and evaporating the solvent to obtain carbon fixation and sink enhancement composite rice husk charcoal;
[0031] (5) Mix the composite rice husk charcoal and soil in a volume ratio of 1:9, and then fill the soil into forest holes with a depth of 0 to 40 cm.
[0032] Embodiment 2:
[0033] (1) crushing rice husks to a D90 of less than 5 mm, and then drying at below 120° C. until the volume no longer decreases, thereby obtaining rice husk powder; heating the rice husk powder to 500° C. at a heating rate of 100° C. / h, naturally cooling the rice husk powder to 400° C. and maintaining the temperature for 0.5 to 1 h, and then naturally cooling the temperature to room temperature to obtain rice husk charcoal;
[0034] (2) immersing the rice husk charcoal in water, exhausting the gas, and freezing it until the center temperature is below -18°C to obtain ice-containing rice husk charcoal;
[0035] (3) The ice-containing rice husk charcoal is taken out and allowed to stand until water droplets are generated on the surface and converge and flow down, and then 0.1 times the mass of calcium bicarbonate of the ice-containing rice husk charcoal is added, mixed and ground for 2 hours, and then calcined at 500°C for 1 hour, and naturally cooled to room temperature to obtain calcified rice husk charcoal;
[0036] (4) dispersing ethylenediaminetetraacetic acid in a sodium hydroxide solution with a pH of 12 to obtain a complexing solution; fully dispersing calcified rice husk charcoal with a mass 10 times that of ethylenediaminetetraacetic acid in water at 2 to 6° C., injecting carbon dioxide into the water until the pH no longer changes, then adding the complexing solution, mixing and stirring until the pH of the system no longer changes, and evaporating the solvent to obtain carbon fixation and sink enhancement composite rice husk charcoal;
[0037] (5) Mix the composite rice husk charcoal and soil in a volume ratio of 1:9, and then fill the soil into forest holes with a depth of 0 to 40 cm.
[0038] Embodiment 3:
[0039] (1) crushing rice husks to a D90 of less than 5 mm, and then drying at below 120° C. until the volume no longer decreases, thereby obtaining rice husk powder; heating the rice husk powder to 500° C. at a heating rate of 100° C. / h, naturally cooling the rice husk powder to 400° C. and maintaining the temperature for 0.5 to 1 h, and then naturally cooling the temperature to room temperature to obtain rice husk charcoal;
[0040] (2) immersing the rice husk charcoal in water, exhausting the gas, and freezing it until the center temperature is below -18°C to obtain ice-containing rice husk charcoal;
[0041] (3) The ice-containing rice husk charcoal is taken out and allowed to stand until water droplets are generated on the surface and converge and flow down, and then 0.05 times the mass of calcium bicarbonate as the ice-containing rice husk charcoal is added, mixed and ground for 1 hour, and then calcined at 500°C for 1 hour, and naturally cooled to room temperature to obtain calcified rice husk charcoal;
[0042] (4) dispersing ethylenediaminetetraacetic acid in a sodium hydroxide solution with a pH of 12 to obtain a complexing solution; fully dispersing calcified rice husk charcoal with a mass 10 times that of ethylenediaminetetraacetic acid in water at 2 to 6° C., injecting carbon dioxide into the water until the pH no longer changes, then adding the complexing solution, mixing and stirring until the pH of the system no longer changes, and evaporating the solvent to obtain carbon fixation and sink enhancement composite rice husk charcoal;
[0043] (5) Mix the composite rice husk charcoal and soil in a volume ratio of 1:9, and then fill the soil into forest holes with a depth of 0 to 40 cm.
[0044] Embodiment 4:
[0045] (1) crushing rice husks to a D90 of less than 5 mm, and then drying at below 120° C. until the volume no longer decreases, thereby obtaining rice husk powder; heating the rice husk powder to 500° C. at a heating rate of 100° C. / h, naturally cooling the rice husk powder to 400° C. and maintaining the temperature for 0.5 to 1 h, and then naturally cooling the temperature to room temperature to obtain rice husk charcoal;
[0046] (2) immersing the rice husk charcoal in water, exhausting the gas, and freezing it until the center temperature is below -18°C to obtain ice-containing rice husk charcoal;
[0047] (3) The ice-containing rice husk charcoal is taken out and allowed to stand until water droplets are generated on the surface and converge and flow down, and then 0.1 times the mass of calcium bicarbonate of the ice-containing rice husk charcoal is added, mixed and ground for 1 hour, and then calcined at 500°C for 1 hour, and naturally cooled to room temperature to obtain calcified rice husk charcoal;
[0048] (4) dispersing ethylenediaminetetraacetic acid in a sodium hydroxide solution with a pH of 12 to obtain a complexing solution; fully dispersing calcified rice husk charcoal with a mass 20 times that of ethylenediaminetetraacetic acid in water at 2 to 6° C., injecting carbon dioxide into the water until the pH no longer changes, then adding the complexing solution, mixing and stirring until the pH of the system no longer changes, and evaporating the solvent to obtain carbon fixation and sink enhancement composite rice husk charcoal;
[0049] (5) Mix the composite rice husk charcoal and soil in a volume ratio of 1:9, and then fill the soil into forest holes with a depth of 0 to 40 cm.
[0050] Comparative Example 1:
[0051] (1) crushing rice husks to a D90 of less than 5 mm, and then drying at below 120° C. until the volume no longer decreases, thereby obtaining rice husk powder; heating the rice husk powder to 400° C. at a heating rate of 100° C. / h, maintaining the temperature for 2 h, and naturally cooling to room temperature to obtain rice husk charcoal;
[0052] (5) Mix the composite rice husk charcoal and soil in a volume ratio of 1:9, and then fill the soil into forest holes with a depth of 0 to 40 cm.
[0053] Comparative Example 2:
[0054] Instead of mixing composite rice husk charcoal with soil, ordinary soil is used to fill the forest holes at a depth of 0 to 40 cm.
[0055] Preparation and testing of samples of the embodiments:
[0056] The study area is located in Yancheng City, Jiangsu Province, in the transition zone between the northern subtropical zone and the warm temperate zone. It belongs to the monsoon climate zone, with an average annual temperature of 14°C and an annual precipitation of about 1000 mm. It is located on the coast, with a flat terrain, a soil salt content of 3.4-4.0 g / kg, and an average pH value of more than 8.5. Due to the high salt content of the soil, it is difficult for plants to survive and grow.
[0057] The test ridge spacing is 3m, the height is 0.4m, and the bottom width is 0.6m. The tree species are arranged from north to south as southern poplar, privet, Virginia oak, beech and Taiwan poplar. The plant spacing is 2m×3m, and 10 replicates. Ten trees of the same species are planted on each ridge 20m from north to south, and different tree species are spaced 1.5m apart. Every 3 ridges form a group, and each embodiment and comparative example is set up as a group. The land is prepared and planted in spring, and the afforestation hole specifications are 40cm×40cm×40cm. When afforestation, fill the forest hole with soil according to the carbon fixation and sink method of each embodiment and comparative example. Samples are taken in 3 layers (0-10cm, 10-40cm and 40-100cm) in each young forest, repeated 3 times, and the survival rate is observed, and the soil organic matter content and soil carbon density at a depth of 1m soil layer are measured.
[0058] The results are as follows:
[0059] Table 1:
[0060]
[0061] It can be seen from the survival rates in Table 1 that the soil mixed with ordinary rice husk charcoal in Comparative Example 1 can significantly improve the survival rate of trees, and the survival rate of trees planted in the soil mixed with the composite rice husk charcoal of the present invention in each embodiment is also significantly higher than that of Comparative Example 1 mixed with ordinary rice husk charcoal, indicating that rice husk charcoal, especially the composite rice husk charcoal of the present invention, does have a good effect in promoting the growth of young forests. Among them, the promoting effect of Examples 3 and 4 with less calcium bicarbonate and ethylenediaminetetraacetic acid added is not as good as that of Examples 1 and 2 with higher content, indicating that the addition of calcium and nitrogen is conducive to improving the growth-promoting effect of composite rice husk charcoal.
[0062] Table 2:
[0063]
[0064] It can be seen from Table 2 that compared with Comparative Example 2, the soil organic matter content of Comparative Example 1 and the remaining embodiments with the addition of rice husk charcoal is significantly increased, and the increase in soil organic matter of each embodiment with the addition of the composite rice husk charcoal of the present invention is more obvious, which is also greatly improved compared with Comparative Example 1.
[0065] Table 3:
[0066]
[0067] As can be seen from Table 3, the carbon density of Comparative Example 1 with the addition of rice husk charcoal is increased by 22.67%, 101.39% and 18.82% respectively compared with Comparative Example 2 of ordinary soil, and rice husk charcoal can significantly increase the carbon density of the soil. In the soil layer of 10 to 40 cm, the soil carbon density of the composite rice husk charcoal of the present invention is increased by more than 135% compared with Comparative Example 2, and the highest is close to 150%, indicating that the carbon fixation capacity of the composite rice husk charcoal of the present invention is significantly higher than that of ordinary rice husk charcoal.
[0068] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.
Claims
1. A composite rice husk charcoal for improving soil, characterized in that: The preparation method comprises the following steps: preparing rice husk charcoal using rice husk, then mixing the rice husk charcoal with calcium bicarbonate, and then calcining to obtain calcified rice husk charcoal; and subjecting the calcified rice husk charcoal to alkali treatment to obtain carbon fixation and sink enhancement composite rice husk charcoal.
2. The composite rice husk charcoal for improving soil according to claim 1, characterized in that: The preparation of the carbon fixation and sink-enhancing composite rice husk charcoal comprises the following steps: a. Freezing the rice husk charcoal with water to obtain ice-containing rice husk charcoal; b. Take out the ice-containing rice husk charcoal and let it stand until water droplets appear on the surface and flow down, then add calcium bicarbonate, mix and grind for 1 to 2 hours, then calcine at 400 to 550 ° C for 1 to 2 hours, and naturally cool to room temperature to obtain calcified rice husk charcoal; c. Disperse ethylenediaminetetraacetic acid in a sodium hydroxide solution with a pH of 10 to 13 to obtain a complexing solution; fully disperse the calcified rice husk charcoal in cold water, and inject carbon dioxide into it until the pH no longer changes, then add the complexing solution, mix and stir until the pH of the system no longer changes, and evaporate the solvent to obtain composite rice husk charcoal.
3. The composite rice husk charcoal for improving soil according to claim 2, characterized in that: The freezing treatment in step a is to immerse the rice husk charcoal in water, expel the gas, and then freeze it to a central temperature below -18°C.
4. The composite rice husk charcoal for improving soil according to claim 2, characterized in that: The mass ratio of the calcium bicarbonate to the ice-containing rice husk charcoal in step b is 1:10-20.
5. The composite rice husk charcoal for improving soil according to claim 2, characterized in that: In step c, the mass ratio of EDTA to calcified rice husk charcoal is 1:10-20.
6. The composite rice husk charcoal for improving soil according to claim 2, characterized in that: The cold water in step c is water at 0-8°C.
7. The composite rice husk charcoal for improving soil according to claim 2, characterized in that: The preparation of the rice husk charcoal comprises the following steps: crushing the rice husk, and then drying it at below 120° C. until the volume no longer decreases to obtain rice husk powder; heating the rice husk powder to 450-550° C. at a heating rate of 100° C. / h, naturally cooling it to 350-450° C. and maintaining it for 0.5-1h, and naturally cooling it to room temperature to obtain rice husk charcoal.
8. The composite rice husk charcoal for improving soil according to claim 7, characterized in that: The rice husk is crushed to a D90 of less than 5 mm.
9. A method for improving soil by using composite rice husk carbon to fix carbon and increase carbon sinks according to any one of claims 1 to 8, characterized in that: The composite rice husk charcoal is mixed with soil in a volume ratio of 1:2.3 to 18, and then a soil layer not less than 40 cm thick is replaced.
10. The carbon sequestration and sink enhancement method according to claim 9, characterized in that: The composite rice husk charcoal was mixed with soil in a volume ratio of 1:9.