Preparation method and application of mineral smoke modified biomass charcoal

Abstract

The invention discloses a preparation method and application of mineral smoke modified biomass charcoal, and belongs to the technical field of biomass charcoal. The preparation method comprises the following steps: grinding organic wastes (distillers' grains, tobacco powder, straws and the like), sieving with a 2mm sieve, and carrying out anaerobic thermal cracking at 400-500 DEG C for 1.5-2.5 hours to obtain biomass charcoal; the mineral smoke powder modified biomass charcoal is prepared by uniformly mixing smoke powder and a silicon-calcium-magnesium fertilizer according to a certain mass ratio (such as 4: 1) and then carrying out thermal cracking under the same conditions. The prepared biomass charcoal and mineral smoke modified biomass charcoal can be applied as a base fertilizer before crop planting, can also be matched with urea, calcium superphosphate and potassium sulfate to be used as a fertilizer, and can also be used for changing the pH value of soil and the coefficients of available phosphorus and activated phosphorus. Experiments show that compared with treatment without fertilization and single application of nitrogen, phosphorus and potassium, the application of the biomass charcoal and the mineral smoke modified biomass charcoal can obviously improve the pH value, the available phosphorus content and the activated phosphorus coefficient of the soil, and an effective way is provided for resource utilization of organic wastes and soil improvement.

Description

Technical Field

[0001] The present invention relates to the technical field of biochar, and more specifically, to a preparation method and application of mineral soot-modified biochar. Background Art

[0002] Yellow soil is a type of agricultural soil that plays an important role in ensuring food security. The main areas where yellow soil is distributed belong to the typical subtropical climate zone, with concurrent rain and heat seasons, strong leaching effects, thin soil layers, mostly acidic, poor soil structure, low organic matter content, low soil phosphorus availability, serious soil erosion, low nutrient utilization rate, and disordered microbial community structure. The low level of agricultural productivity seriously restricts the sustainable agricultural development of the region. In order to achieve high grain yields, intensive farming methods have been adopted for a long time, chemical fertilizers have been blindly and excessively applied, and the input of organic fertilizers has been neglected, which has further accelerated the decline of soil fertility. With the decrease of soil organic matter, the deterioration of soil structure has been aggravated, and the soil organic carbon and nutrient availability have been reduced. Phosphorus is one of the main limiting factors for crop growth in the yellow soil area.

[0003] Currently, there are large quantities of organic solid wastes such as distiller's grains and soot, which are concentrated but not rationally utilized. At present, pyrolysis technology is one of the important means to realize the resource utilization of organic solid wastes. Biochar is a carbon-rich solid material produced by the pyrolysis of biomass under anaerobic conditions, which can be added to the soil as an important means to mitigate climate change through carbon sequestration, thereby turning organic wastes into valuable resources. Due to the porous structure, large surface area, abundant surface groups, and high mineral content of biochar, it can be functionalized to improve the availability of soil phosphorus. Biochar can affect soil phosphorus transformation by increasing soil organic carbon, improving soil aggregate stability, enhancing soil phosphatase activity, microbial biomass, or microbial community structure. These effects can promote the transformation of organic phosphorus pools and insoluble inorganic phosphorus into available phosphorus, form or regenerate easily decomposable active organic phosphorus, thereby improving the absorption and utilization of phosphorus by plants. The interaction between biochar types and climatic conditions, soil types, and fertilization status will also lead to the uncertainty of the interaction between biochar and organisms. Domestic and foreign scientific researchers have done a lot of research work on biochar preparation, soil improvement and fertilization, carbon sequestration and emission reduction, etc. However, due to the wide range of sources of biochar preparation materials and the large differences in application environmental conditions, the effects of biochars from different sources on the transformation of phosphorus forms in yellow soil and crop production are still not comprehensively understood.

[0004] The sources of carbonization raw materials for biochar are diverse, and there are significant differences in the characteristics and functions of biochars from organic wastes of different sources, such as yield, specific surface area, pore size distribution, elemental composition, and functional groups. The raw materials play a major role in preparing biochars with significantly different chemical properties. Screening suitable biomass raw materials is crucial for obtaining biochars with desired characteristics. Therefore, it has become an urgent problem to be solved at present to utilize and transform organic solid wastes such as distiller's grains and tobacco dust on a large scale locally by using modern pyrolysis technology to turn waste into treasure. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method and application of mineral tobacco dust modified biochar, which utilizes and transforms organic solid wastes such as distiller's grains and tobacco dust by using modern pyrolysis technology and is applied to the cultivation of crops and the improvement of soil.

[0006] The above technical purpose of the present invention is achieved through the following technical solutions: A preparation method of modified biochar, after grinding the organic waste and passing it through a sieve with a pore size of 2 mm, adding it to a carbonization device, and carrying out anaerobic pyrolysis at 400 °C - 500 °C for 1.5 h - 2.5 h to prepare biochar.

[0007] It is further set that: The organic waste includes distiller's grains, tobacco dust, and straw, and they are respectively prepared into distiller's grains biochar, tobacco dust biochar, and straw biochar.

[0008] It is further set that: Anaerobic pyrolysis is carried out at 450 °C for 2 h to prepare biochar.

[0009] The present invention also provides an application of the biochar prepared by the above preparation method, applying the biochar as a base fertilizer before crop planting.

[0010] The present invention also provides an application of the biochar prepared by the above preparation method, the application of biochar together with urea, superphosphate, and potassium sulfate as fertilizers.

[0011] The present invention also provides an application of the biochar prepared by the above preparation method, the application of biochar in changing soil pH value, available phosphorus, and activated phosphorus coefficient.

[0012] Based on the above preparation method, the present invention further provides a preparation method of mineral tobacco dust modified biochar, grinding the tobacco dust and passing it through a sieve with a pore size of 2 mm, fully mixing the tobacco dust and calcium silicate magnesium fertilizer according to a certain mass ratio, adding it to a carbonization device, and carrying out anaerobic pyrolysis at 400 °C - 500 °C for 1.5 h - 2.5 h to prepare mineral tobacco dust modified biochar.

[0013] It is further set that: The tobacco dust and calcium silicate magnesium fertilizer are fully mixed according to a mass ratio of 4:1.

[0014] It is further set that mineral soot-modified biochar is prepared by anaerobic pyrolysis at 450 °C for 2 h.

[0015] The present invention also provides an application of the mineral soot-modified biochar prepared by the above preparation method, and the mineral soot-modified biochar is applied as a base fertilizer before crop planting.

[0016] The present invention also provides an application of the mineral soot-modified biochar prepared by the above preparation method, and the mineral soot-modified biochar, urea, superphosphate, and potassium sulfate are used together as fertilizers.

[0017] It is further set that the dosage of the mineral soot-modified biochar is 20 t·hm -2。

[0018] The present invention also provides an application of the mineral soot-modified biochar prepared by the above preparation method, and the application of the mineral soot-modified biochar in changing soil pH value, available phosphorus, and activated phosphorus coefficient.

[0019] In summary, the present invention has the following beneficial effects:

[0020] Realize the resource utilization of organic waste: Use organic solid wastes such as distiller's grains, soot, and straw as raw materials to prepare biochar, avoid the accumulation of waste and environmental pollution, realize the recycling of resources, and turn waste into treasure.

[0021] Improve soil properties: Adjust the soil pH value, increase the soil available phosphorus content, and enhance the soil activated phosphorus coefficient.

[0022] Enhance soil fertility: Biochar is rich in elements such as carbon, nitrogen, and phosphorus, and its ash also contains base cations and exchangeable cations. Among different biochars, the ash, base cations, and exchangeable cation contents of soot biochar and mineral soot-modified biochar are relatively high, which supplement nutrients to the soil, help improve soil fertility, improve soil structure, and enhance the soil's ability to retain fertilizer and water.

[0023] Promote crop growth: Reasonable nutrient supply and improvement of soil environment create favorable conditions for crop growth. In the maize-cabbage rotation experiment, the application of biochar and mineral soot-modified biochar in combination with nitrogen, phosphorus, and potassium fertilizers provides sufficient nutrients for crops, is conducive to crop growth and development, and has a potential effect on improving crop yield and quality.

[0024] The present invention reveals the mechanism of action of mineral soot-modified biochar on phosphorus activation in the yellow soil of the maize-cabbage rotation system, providing a theoretical basis for the resource utilization of agricultural organic solid waste, soil fertility improvement, annual nutrient efficient management of crops, and high-quality sustainable development of agriculture in mountainous yellow soil areas. Brief Description of the Drawings

[0025] Figure 1 is a carbonization device for preparing biomass charcoal in an embodiment of the present invention;

[0026] Figure 2 is a scanning electron microscope photograph (×5000 times) of biomass charcoal in an embodiment of the present invention, where (a) is distiller's grains biomass charcoal; (b) is tobacco dust biomass charcoal; (c) is mineral-modified tobacco dust biomass charcoal; (d) is corn straw biomass charcoal;

[0027] Figure 3 is the XRD pattern of 4 types of biomass charcoal in an embodiment of the present invention.

[0028] Figure 4 is the FTIR-PAS pattern of 4 types of biomass charcoal in an embodiment of the present invention;

[0029] Figure 5 is the soil pH value under different treatments in (a) 2018 and (b) 2019 in an embodiment of the present invention;

[0030] Figure 6 is the available phosphorus content in the soil under different treatments in (a) 2018 and (b) 2019 in an embodiment of the present invention;

[0031] Figure 7 is the soil activated phosphorus coefficient under different treatments in (a) 2018 and (b) 2019 in an embodiment of the present invention. Detailed Description of the Invention

[0032] The following further describes the present invention in detail Figure 1-7 in conjunction with the accompanying drawings.

[0033] Example: A preparation method and application of mineral tobacco dust-modified biomass charcoal are as Figure 1 - Figure 7 shown. Characteristic agricultural organic wastes such as distiller's grains, tobacco dust, and straw are selected as raw materials, and the straw is corn straw. A special biomass carbonization furnace (SSDP-5000-A, Huadian Environmental Protection Machinery Manufacturing Co., Ltd., Huai'an, Jiangsu) as Figure 1 shown is used to prepare biomass charcoal through anaerobic pyrolysis. Each organic waste is ground and passed through a sieve with a 2 mm pore size, and then anaerobically thermally pyrolyzed at 400°C - 500°C for 1.5 h - 2.5 h to prepare biomass. Mineral-modified tobacco dust biomass charcoal is prepared by fully mixing tobacco dust and calcium silicate magnesium fertilizer in a mass ratio of 4:1. All raw materials in this example are prepared into biomass charcoal through anaerobic thermal pyrolysis at 450°C for 2 h by a carbonization device. As Figure 2 shown, they are respectively the generated distiller's grains biomass charcoal ( Figure 2 (a)), tobacco dust biomass charcoal ( Figure 2b), Mineral soot-modified biochar ( Figure 2 c) and corn straw biochar ( Figure 2 d).

[0034] A total of 6 experimental treatment groups were set up: (1) No fertilization (CK); (2) Nitrogen, phosphorus and potassium (F); (3) Distiller's grains biochar + nitrogen, phosphorus and potassium (DBF); (4) Soot biochar + nitrogen, phosphorus and potassium (TBF); (5) Mineral soot-modified biochar + nitrogen, phosphorus and potassium (TMBF); (6) Corn straw biochar + nitrogen, phosphorus and potassium (MSBF).

[0035] Select plots with an area of 4m × 1.5m. There are 18 plots in total. Cement ridges are used to separate each plot. A randomized block design is adopted. The rotation system is corn - Chinese cabbage rotation. Each treatment group has 3 replicates. There are irrigation facilities. The types of chemical fertilizers applied are urea (N 46%), superphosphate (P2O5 12%), and potassium sulfate (K2O 50%). The application rates of distiller's grains biochar, soot biochar, mineral-modified soot biochar and corn straw biochar are all 20t·hm -2 . The biochar was applied once as a base fertilizer before the first-season corn in 2018 and was not applied in subsequent corn and Chinese cabbage seasons. The nutrient inputs in the corn season were N 240kg·hm -2 , P2O5 120kg·hm -2 and K2O 180kg·hm -2 ; The nutrient inputs in the Chinese cabbage season were N 300kg·hm -2 , P2O5 150 kg·hm -2 and K2O 225kg·hm -2 ; Before transplanting corn and Chinese cabbage, all the phosphate and potassium fertilizers were applied as base fertilizers. Urea was applied as base fertilizer and one top dressing (the base - top dressing ratio was 6:4). The nitrogen, phosphorus and potassium nutrient inputs in the F, DBF, TBF, TMBF and MSBF treatments were kept consistent. The corn planting density was 48000 plants·hm -2 , and the Chinese cabbage planting density was 57000 plants·hm -2 . A 2 - year land - leveling experiment was carried out before the experiment, with ryegrass as the crop. The first-season corn was transplanted on April 25, 2018 and harvested on September 17, 2018. The first-season Chinese cabbage was transplanted on October 25, 2018 and harvested on February 21, 2019. The second-season corn was transplanted on April 19, 2019 and harvested on September 10, 2019. The second-season Chinese cabbage was transplanted on October 20, 2019 and harvested on January 18, 2020.

[0036] Table 1 Basic physical and chemical properties of biochar

[0037]

[0038] Note: DBF represents distiller's grains biochar, TBF represents tobacco dust biochar, TMBF represents mineral-modified tobacco dust biochar, and MSBF represents corn straw biochar. The same applies hereinafter.

[0039] As can be seen from the basic physical and chemical properties of the biochars in Table 1, the pH values of the four tested biochars all showed alkalinity, among which the mineral-modified tobacco dust biochar and tobacco dust biochar had the strongest alkalinity. From the perspective of the ash content of the biochars, the mineral-modified tobacco dust biochar and tobacco dust biochar had the highest ash content, followed by corn straw and distiller's grains biochar. The order of the total carbon content of each biochar was MSBF > DBF > TBF > TMBF. From the perspective of the total nitrogen and total phosphorus content, the order was DBF > TBF > TMBF > MSBF. The C / N ratio of the MSBF treatment was the highest, followed by the TBF and TMBF treatments, and finally the DBF treatment. From the perspective of base cations and exchangeable cations, both the TBF and TMBF treatments were the highest, the DBF treatment was the second, and finally the MSBF treatment.

[0040] The XRD patterns of different types of biochars are as Figure 3 shown. The distiller's grains biochar had a diffraction peak at 4.24, and this diffraction peak was the diffraction peak of quartz crystals. The tobacco dust biochar had diffraction peaks at 3.13 and 2.22, and these two diffraction peaks were the diffraction peaks of potassium chloride crystals. The mineral-modified tobacco dust biochar had diffraction peaks at 3.87, 3.05, 2.50, 2.29, 2.10, 1.92, and 1.88 respectively, and these diffraction peaks were the diffraction peaks of calcium carbonate crystals. The corn straw biochar had a diffraction peak at 4.24, and this diffraction peak was the diffraction peak of quartz crystals, which was consistent with the distiller's grains biochar.

[0041] The morphological structure changes of different types of biochars were observed by scanning electron microscopy (SEM), as Figure 2 . From the comparison of the three biochars of distiller's grains biochar, tobacco dust biochar, and corn straw biochar, the tobacco dust biochar showed a macroporous structure with smooth pores and a smooth surface. However, the pores of the distiller's grains biochar were damaged and blocked, indicating roughness, and the pores of the corn straw biochar were damaged and blocked, with a relatively smooth surface. From the comparison of the tobacco dust biochar before and after modification, the biochar obtained by anaerobic co-pyrolysis of tobacco dust and calcium silicate magnesium minerals had damaged and blocked pores and a rough surface.

[0042] Figure 4 is the FTIR-PAS spectrum of distiller's grains biochar, tobacco dust biochar, mineral-modified tobacco dust biochar, and corn straw biochar at 450 °C, which reflects the change of the functional groups on the biochar surface with the pyrolysis temperature. The absorption peak of the distiller's grains biochar at 1590 cm -1 was the antisymmetric stretching of -COO - . The absorption peak at 1030 cm-1 The absorption peak at -1 is the stretching vibration of the silicon-oxygen bond (Si-O). The absorption peak of the tobacco foam biochar at 1400 cm -1 is the bending vibration and symmetric stretching of -COO - . The absorption peak at 1100 cm -1 and 860 cm -1 is the out-of-plane bending of CO3 2- . The absorption peak of the mineral-modified tobacco foam biochar at 3400 cm -1 is the stretching vibration of -OH. The absorption peak at 1400 cm -1 is the bending vibration and symmetric stretching of -COO - . The absorption peak at 860 cm -1 is the out-of-plane bending of CO3 2- . The absorption peak of the corn straw biochar at 1030 cm -1 is the stretching vibration of the silicon-oxygen bond (Si-O), indicating the formation of SiO2 crystals in the corn straw biochar. This is consistent with the results of the XRD pattern, which also shows the formation of SiO2 crystals in the corn straw biochar.

[0043] Figure 5 are the soil pH values under different treatments. (a) is the soil pH value after the Chinese cabbage harvest in 2018; (b) is the soil pH value after the Chinese cabbage harvest in 2019 (different lowercase letters indicate significant differences between all treatments (p < 0.05)). It can be seen from Figure 5 that compared with the CK treatment, the soil pH values of the maize-Chinese cabbage annual rotation with the DBF, TBF, TMBF, and MSBF treatments increased by 0.12 - 1.12 and 0.22 - 1.50 in 2018 and 2019, respectively. Except for the DBF treatment in 2018, the differences reached a significant level. Compared with the F treatment, the soil pH values of the maize-Chinese cabbage annual rotation with the DBF, TBF, TMBF, and MSBF treatments increased by 0.12, 0.84, 1.12, and 0.75 in 2018, respectively. Except for the DBF treatment, the differences reached a significant level; in 2019, the pH values of the DBF, TBF, TMBF, and MSBF treatments were increased by 0.44, 0.79, 1.67, and 0.75 compared with the F treatment, and the differences reached a significant level.

[0044] Figure 6 are the soil available phosphorus contents under different treatments. (a) is the soil available phosphorus content after the Chinese cabbage harvest in 2018; (b) is the soil available phosphorus content after the Chinese cabbage harvest in 2019 (different lowercase letters indicate significant differences between all treatments (p < 0.05)). It can be seen from Figure 6It can be seen that compared with the CK treatment, the available phosphorus content in the soil of the F, DBF, TBF, TMBF, and MSBF treatments increased by 0.24 - 6.36 and 2.02 - 7.12 mg·kg in 2018 and 2019, respectively. -1 , and the differences all reached a significant level. Compared with the F treatment, the available phosphorus content in the soil of the DBF, TBF, TMBF, and MSBF treatments increased by 4.93, 4.36, 6.12, and 1.50 mg·kg in 2018, respectively. -1 , and the differences reached a significant level; in 2019, the available phosphorus content in the soil of the DBF, TBF, TMBF, and MSBF treatments increased by 2.57, 4.03, 5.10, and 0.24 mg·kg compared with the F treatment, respectively. -1 , and the differences reached a significant level. From the two - year average level, the available phosphorus content in the soil was the highest in the TMBF treatment.

[0045] Figure 7 The coefficients of activated phosphorus in the soil under different treatments. (a) is the coefficient of activated phosphorus in the soil after the Chinese cabbage harvest in 2018; (b) is the coefficient of activated phosphorus in the soil after the Chinese cabbage harvest in 2019 (different lowercase letters indicate significant differences between all treatments (p < 0.05)). It can be seen that Figure 7 compared with the CK treatment, the coefficients of activated phosphorus in the soil of the F, DBF, TBF, TMBF, and MSBF treatments for the annual rotation of maize - Chinese cabbage increased by 9.2% - 365.0% and 143.3% - 519.7% in 2018 and 2019, respectively, and the differences reached a significant level. Compared with the F treatment, the coefficients of activated phosphorus in the soil of the DBF, TBF, TMBF, and MSBF treatments for the annual rotation of maize - Chinese cabbage increased by 100.3% - 325.9% in 2018, respectively, and the differences reached a significant level; in 2019, the coefficients of activated phosphorus in the soil of the DBF, TBF, TMBF, and MSBF treatments for the annual rotation of maize - Chinese cabbage increased by 44.1% - 154.7%, respectively, and the differences reached a significant level. From the two - year average level, the coefficient of activated phosphorus in the soil was the highest in the TMBF treatment.

[0046] This specific embodiment is only an explanation of the present invention and is not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A preparation method of modified biochar, characterized in that, The organic waste is ground and passed through a 2 mm aperture sieve, then added to a carbonization device and anaerobically pyrolyzed at 400°C-500°C for 1.5h-2.5h to prepare biochar.

2. The preparation method of the modified biomass carbon according to claim 1, characterized in that, The organic waste includes distiller's grains, smoke foam and straw, which are prepared into distiller's grains biomass charcoal, smoke foam biomass charcoal and straw biomass charcoal respectively.

3. The preparation method of the modified biomass carbon according to claim 1, characterized in that, Biochar was prepared by anaerobic pyrolysis at 450 °C for 2 h.

4. Use of the biochar prepared by the preparation method according to any one of claims 1-3, characterized in that, Apply biochar as base fertilizer before planting crops.

5. Use of the biochar prepared by the preparation method according to any one of claims 1-3, characterized in that, Biochar is used as fertilizer together with urea, superphosphate and potassium sulfate.

6. Use of the biochar prepared by the preparation method according to any one of claims 1-3, characterized in that Application of biochar in changing soil pH, available phosphorus and activated phosphorus coefficient.

7. A preparation method of mineral smoke-modified biomass carbon, characterized in that, The smoke foam is ground and passed through a 2mm aperture sieve. The smoke foam and silicon, calcium and magnesium fertilizers are fully mixed in a certain mass ratio, added to the carbonization equipment, and anaerobically pyrolyzed at 400°C-500°C for 1.5h-2.5h to prepare mineral smoke foam modified biochar.

8. The preparation method of a mineral soot-modified biomass carbon according to claim 7, characterized in that, Mix smoke foam and silicon-calcium-magnesium fertilizer thoroughly in a mass ratio of 4:

1.

9. The preparation method of a mineral soot-modified biomass carbon according to claim 7, characterized in that, Mineral smoke modified biochar was prepared by anaerobic pyrolysis at 450℃ for 2h.

10. Use of the mineral soot-modified biomass carbon prepared by the preparation method according to any one of claims 7-9, characterized in that Mineral smoke modified biochar is applied as base fertilizer before crop planting.

11. Use of the biochar prepared by the preparation method according to any one of claims 7-9, characterized in that, Application of mineral smoke modified biochar together with urea, superphosphate and potassium sulfate as fertilizer.

12. Use of the biochar prepared by the preparation method according to claim 11, characterized in that, The dosage of mineral soot-modified biochar is 20 t·hm -2 .

13. Use of the mineral soot-modified biomass carbon prepared by the preparation method according to any one of claims 7-9, characterized in that, Application of mineral smoke modified biochar in changing soil pH, available phosphorus and activated phosphorus coefficient.

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