A method for preparing biochar based on eucalyptus and its application

Abstract

This invention relates to the field of biochar preparation technology, specifically to a method for preparing biochar based on eucalyptus and its applications. This invention utilizes response surface methodology and a high-temperature pyrolysis method to prepare biochar. Through the synergistic effect of a micropore-dominated pore structure and surface functional groups, the final biochar can balance adsorption capacity and selectivity. Furthermore, the raw material used in this invention is primarily eucalyptus waste, which effectively improves the utilization rate of eucalyptus waste. Simultaneously, the resulting biochar exhibits outstanding performance in multiple fields, including soil improvement, pollution control, and catalytic materials. It reduces reliance on chemical fertilizers, lowers sulfur emissions from fuel oil, and adsorbs and catalyzes carbon dioxide, demonstrating broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of biochar preparation technology, and in particular to a method for preparing biochar based on eucalyptus trees and its application. Background Technology

[0002] Biochar is an important environmental functional material, widely used in soil improvement, pollutant adsorption, and other fields. Currently, biochar is mostly prepared using raw materials such as straw and wood, but this method suffers from problems such as limited raw material sources, complex preparation processes, and high costs.

[0003] Eucalyptus is a fast-growing tree species characterized by its short growth cycle (5-7 years to mature) and large biomass. However, the intensive planting of eucalyptus leads to ecological problems such as soil acidification (pH generally < 5.5) and reduced phosphorus availability (available phosphorus < 5 mg / kg). Biochar, a carbon-rich material produced by the pyrolysis of biomass under anaerobic conditions, possesses a porous structure and abundant surface functional groups, exhibiting unique advantages in soil remediation, pollutant adsorption, and catalysis. Currently, eucalyptus is used to prepare biochar; however, existing technologies for the preparation and application of biochar from eucalyptus waste face the following key bottlenecks, hindering its efficient utilization:

[0004] Traditional pyrolysis processes (such as tubular furnace pyrolysis) can form porous structures, but the pore size distribution is uneven and there is a lack of directional control methods, which limits the adsorption rate of specific pollutants.

[0005] Existing biochar surface modification technologies (such as acid and alkali immersion and simple loading) suffer from problems such as uneven functional group loading and poor stability, which limits their application in many scenarios.

[0006] The lack of full-value utilization of eucalyptus waste and the absence of co-production processes: Current technologies only focus on the production of biochar as a single product, neglecting the synergistic transformation of other components in eucalyptus bark, branches and other wastes, resulting in resource waste.

[0007] To address the aforementioned technical issues, there is an urgent need to develop a method for preparing biochar based on eucalyptus trees and its applications. Summary of the Invention

[0008] In view of this, the purpose of this invention is to propose a method for preparing biochar based on eucalyptus and its application, which simultaneously solves key problems of pore structure, surface function and resource utilization, promotes the high-value utilization of eucalyptus waste and the coordinated improvement of the ecological environment, and expands the efficient utilization of eucalyptus biochar in multiple fields.

[0009] To achieve the above objectives, this invention provides a method for preparing biochar based on eucalyptus trees and its application.

[0010] A method for preparing biochar based on eucalyptus trees includes the following steps:

[0011] Step S1. Raw material pretreatment: The eucalyptus raw material is crushed and dried at 65℃ for 24 hours to obtain the raw material;

[0012] Step S2. Pyrolysis treatment: Using a high-temperature pyrolysis method, the dried raw materials are placed in an OTL1600 tube furnace to obtain porous materials;

[0013] Step S3. Cooling and Collection: After the porous material is naturally cooled to room temperature, it is ground to 100 mesh to obtain biochar.

[0014] Preferably, the eucalyptus raw materials mentioned in step S1 include eucalyptus materials and agricultural waste;

[0015] The mass ratio of eucalyptus material to agricultural waste in step S1 is 30-40:10-15;

[0016] The particle size of the eucalyptus material after crushing in step S1 is 2-5 mm;

[0017] The eucalyptus material is any one or more of eucalyptus bark, eucalyptus branches, eucalyptus roots, and eucalyptus leaves;

[0018] The agricultural waste is either rice husks or corn stalks.

[0019] Preferably, the eucalyptus raw material described in step S1 is crushed and dried, then treated with an acid solution, and finally subjected to hydrothermal carbonization to obtain the raw material.

[0020] Preferably, the acid used in the acid solution treatment process is a 5% sulfuric acid solution;

[0021] The hydrothermal carbonization temperature is 180℃, and the hydrothermal carbonization time is 18h.

[0022] Eucalyptus material can be treated with a 5% sulfuric acid solution and then hydrothermally carbonized at 180℃ for 18 hours to destroy the lignocellulose structure and improve the subsequent activation efficiency.

[0023] Preferably, the process of treating the raw material by high-temperature pyrolysis in step S2 is as follows: a catalyst is added to the raw material, nitrogen is used as a protective gas, and a segmented heat preservation process is adopted to perform heat preservation treatment to obtain porous material.

[0024] Preferably, the catalyst is KOH, and the mass ratio of the raw material to the catalyst is 1:3. The segmented heat preservation process is as follows: first, the temperature is raised to 350℃ at a heating rate of 5℃ / min and held for 1 hour; then, the temperature is raised to 550℃ at a heating rate of 10℃ / min and held for 2 hours; finally, the temperature is raised to 750℃ at a heating rate of 15℃ / min and held for 3 hours.

[0025] Segmented insulation process can form a high proportion of micropores, thereby increasing the specific surface area.

[0026] Preferably, the porous material in step S3 undergoes surface functionalization modification before grinding. The surface functionalization modification process is as follows: the porous material is modified by magnetron sputtering.

[0027] The magnetron sputtering modification process uses nitrogen plasma for magnetron sputtering to load nitrogen functional groups onto the surface of biochar.

[0028] An application of eucalyptus-based biochar preparation, wherein the biochar is prepared by the above-described method and is used for soil phosphorus regulation. For acidic soils with a pH of 5.3-6.96, an application rate of 4%-6% biochar can significantly increase active organic phosphorus and iron phosphorus, reduce occluded phosphorus, and promote the activity of microbial biomass phosphorus and phosphate.

[0029] An application of eucalyptus-based biochar preparation, wherein the biochar is prepared by the above-described method, and the biochar is used for desulfurization. In the field of desulfurization, biochar has a high adsorption capacity for dibenzothiophene, and therefore can remove sulfur compounds from fuel oil.

[0030] An application of eucalyptus-based biochar preparation, wherein the biochar is prepared by the above-described method and is used for CO2 adsorption and catalysis. The surface of the biochar after magnetron sputtering is loaded with nitrogen functional groups, forming Lewis acid sites, which can enhance carbon dioxide catalysis.

[0031] The beneficial effects of this invention are:

[0032] This invention provides a method for preparing biochar based on eucalyptus and its application. The invention utilizes a micropore-dominated pore structure and the synergy of surface functional groups to produce biochar that balances adsorption capacity and selectivity. Furthermore, the raw material used in this invention is mainly eucalyptus waste, which can effectively improve the utilization rate of eucalyptus waste. At the same time, the biochar produced can also be used for soil improvement, pollution control, and catalytic materials, reducing reliance on chemical fertilizers and lowering sulfur emissions from fuel oil, thus having broad application prospects. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the biochar prepared in this invention and its related applications;

[0035] Figure 2 This is a schematic diagram of the structure of the biochar prepared in Example 1 of the present invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0037] Example 1: A method for preparing biochar based on eucalyptus trees, comprising the following steps:

[0038] S1. Raw material pretreatment: First, 30g of eucalyptus bark is crushed to a particle size of 2-5mm, 10g of rice husk is added, and after drying, it is treated with 5% sulfuric acid solution. Finally, it is hydrothermally carbonized at 180℃ for 18h to obtain the raw material.

[0039] S2. Catalytic pyrolysis pore formation treatment: Add 30g KOH to 10g raw material, use nitrogen as protective gas, and carry out pore formation treatment using a segmented heat preservation process. The segmented heat preservation process is as follows: first, heat to 350℃ at a heating rate of 5℃ / min and hold for 1h, then heat to 550℃ at a heating rate of 10℃ / min and hold for 2h, and finally heat to 750℃ at a heating rate of 15℃ / min and hold for 3h to obtain the porous material.

[0040] S3. Surface functionalization modification: The porous material is modified by nitrogen plasma magnetron sputtering to obtain the modified material;

[0041] S4. Post-processing: Grind the modified material to 100 mesh to obtain biochar.

[0042] Example 2: A method for preparing biochar based on eucalyptus trees, comprising the following steps:

[0043] S1. Raw material pretreatment: First, crush 33g of eucalyptus branches to a particle size of 2-5mm, add 12g of corn stalks, dry them, treat them with 5% sulfuric acid solution, and finally carbonize them at 180℃ for 18h to obtain the raw material.

[0044] S2. Catalytic pyrolysis pore formation treatment: Add 30g KOH to 10g raw material, use nitrogen as protective gas, and carry out pore formation treatment using a segmented heat preservation process. The segmented heat preservation process is as follows: first, heat to 350℃ at a heating rate of 5℃ / min and hold for 1h, then heat to 550℃ at a heating rate of 10℃ / min and hold for 2h, and finally heat to 750℃ at a heating rate of 15℃ / min and hold for 3h to obtain the porous material.

[0045] S3. Surface functionalization modification: The porous material is modified by nitrogen plasma magnetron sputtering to obtain the modified material;

[0046] S4. Post-processing: Grind the modified material to 100 mesh to obtain biochar.

[0047] Example 3: A method for preparing biochar based on eucalyptus trees, comprising the following steps:

[0048] S1. Raw material pretreatment: First, crush the mixture of 38g eucalyptus leaves to a particle size of 2-5mm, add 14g rice husks, dry and treat with 5% sulfuric acid solution, and finally carbonize at 180℃ for 18h to obtain the raw material.

[0049] S2. Catalytic pyrolysis pore formation treatment: Add 30g KOH to 10g raw material, use nitrogen as protective gas, and carry out pore formation treatment using a segmented heat preservation process. The segmented heat preservation process is as follows: first, heat to 350℃ at a heating rate of 5℃ / min and hold for 1h, then heat to 550℃ at a heating rate of 10℃ / min and hold for 2h, and finally heat to 750℃ at a heating rate of 15℃ / min and hold for 3h to obtain the porous material.

[0050] S3. Surface functionalization modification: The porous material is modified by nitrogen plasma magnetron sputtering to obtain the modified material;

[0051] S4. Post-processing: Grind the modified material to 100 mesh to obtain biochar.

[0052] Example 4: A method for preparing biochar based on eucalyptus trees, comprising the following steps:

[0053] S1. Raw material pretreatment: First, crush 40g of a mixture of eucalyptus bark, eucalyptus branches and leaves to a particle size of 2-5mm, add 15g of corn stalks, dry and treat with 5% sulfuric acid solution, and finally carbonize at 180℃ for 18h to obtain the raw material.

[0054] S2. Catalytic pyrolysis pore formation treatment: Add 30g KOH to 10g raw material, use nitrogen as protective gas, and carry out pore formation treatment using a segmented heat preservation process. The segmented heat preservation process is as follows: first, heat to 350℃ at a heating rate of 5℃ / min and hold for 1h, then heat to 550℃ at a heating rate of 10℃ / min and hold for 2h, and finally heat to 750℃ at a heating rate of 15℃ / min and hold for 3h to obtain the porous material.

[0055] S3. Surface functionalization modification: The porous material is modified by nitrogen plasma magnetron sputtering to obtain the modified material;

[0056] S4. Post-processing: Grind the modified material to 100 mesh to obtain biochar.

[0057] Application Example 1: An application of eucalyptus-based biochar preparation in soil improvement, the process is as follows:

[0058] Acidic eucalyptus forest soil with a pH of 5.3 was selected, and the biochar prepared in Example 1 was mixed with the soil at a mass ratio of 4%. Soil without added biochar was used as a control group. After 3 months of cultivation, the physicochemical properties of the soil were measured. The results showed that the soil pH of the experimental group with added biochar increased to 6.8, the cation exchange capacity increased by 35%, the available phosphorus content increased by 40%, and the microbial biomass phosphorus increased by 50%. This indicates that the biochar prepared by this invention can effectively improve the properties of acidic soil and enhance phosphorus availability.

[0059] Application Example 2: An application of eucalyptus-based biochar in fuel oil adsorption desulfurization, the process is as follows:

[0060] 1.0 g of dibenzothiophene was dissolved in 1 L of n-octane to prepare a simulated fuel with an initial concentration of 1000 mg / L. 0.5 g of the biochar prepared in Example 1 was weighed and added to 200 mL of the simulated fuel. The mixture was shaken at a constant temperature of 25 °C and 150 rpm. Samples were taken at regular intervals, and the concentration of dibenzothiophene was determined by high performance liquid chromatography. When the adsorption equilibrium was reached, the removal rate of dibenzothiophene reached 92.3%, and the adsorption capacity was 172.5 mg / g, indicating that the biochar prepared in this invention has excellent adsorption performance for dibenzothiophene.

[0061] Application Example 3: An application of eucalyptus-based biochar in carbon dioxide adsorption, the process is as follows:

[0062] The biochar prepared in Example 1 was placed in an adsorption reaction vessel, and the system was first evacuated to 10 °C at 25 °C. -3 The pressure was kept below 100 kPa to remove impurity gases adsorbed on the sample surface. Then, carbon dioxide gas was introduced to bring the system pressure to 100 kPa. The pressure change of the system was recorded at regular intervals. The amount of carbon dioxide adsorbed was calculated according to the ideal gas law. After 24 hours of adsorption reaching equilibrium, the amount of carbon dioxide adsorbed was found to be 3.5 mmol / g.

[0063] Application Example 4: Simulation of Carbon Dioxide Adsorption by Eucalyptus Biochar in Actual Flue Gas

[0064] To simulate the composition of actual flue gas, a mixed gas containing 10% carbon dioxide, 80% nitrogen, 5% oxygen, and 5% water vapor was prepared. A dynamic adsorption experimental setup was constructed, and 0.5g of eucalyptus biochar prepared at 750℃ in Example 1 was packed into an adsorption column. Simulated flue gas was passed through the adsorption column at a certain flow rate (50mL / min), and the concentration of carbon dioxide in the outlet gas was monitored in real time using a gas chromatograph. After 5 hours of adsorption, the carbon dioxide concentration in the outlet gas decreased from 10% to 5%, indicating that the eucalyptus biochar has a certain adsorption and removal capacity for carbon dioxide in a real flue gas environment and possesses potential industrial application value.

[0065] Comparative Example 1:

[0066] Compared with Example 1, this comparative example only omits the KOH activation step in the biochar prepared in Example 1. All other steps and parameters are the same, and will not be repeated here. The final biochar obtained was used for the adsorption experiment of dibenzothiophene. It was found that under the same conditions, its adsorption capacity for dibenzothiophene was 85.2 mg / g, which was much lower than that of the biochar used in Example 1. This shows that KOH activation significantly improves the pore structure and adsorption performance of biochar.

[0067] Comparative Example 2:

[0068] Compared with Example 1, this comparative example only replaces "raw material" with "pine waste". All other steps and parameters are the same, and will not be repeated here. The final biochar obtained was used for the adsorption experiment of dibenzothiophene. It was found that under the same conditions, its adsorption capacity for dibenzothiophene was 150.3 mg / g, which was lower than that of the biochar used in Application Example 1. The biochar prepared from eucalyptus waste as raw material has better adsorption performance, which may be related to the lignin and cellulose content of eucalyptus raw material.

[0069] Comparative Example 3:

[0070] Compared with Example 1, this comparative example only changed the segmented heat preservation process in step S2 to "first heating to 350℃ at a heating rate of 5℃ / min and holding for 1h, then heating to 550℃ at a heating rate of 10℃ / min and holding for 2h, and finally heating to 650℃ at a heating rate of 15℃ / min and holding for 3h to obtain porous material". The other steps and parameters are the same, and will not be repeated in this comparative example. Finally, biochar was obtained and used in carbon dioxide adsorption experiments. It was found that the adsorption capacity of carbon dioxide under the same conditions was 2.8 mmol / g, which was lower than that in Application Example 3. This indicates that the eucalyptus biochar prepared by activation at 750℃ has better carbon dioxide adsorption performance, which may be due to its well-developed pore structure and suitable surface functional group distribution.

[0071] Comparative Example 4:

[0072] Compared with Example 1, this comparative example only changed the segmented heat preservation process in step S2 to "first heating to 350℃ at a heating rate of 5℃ / min and holding for 1h, then heating to 550℃ at a heating rate of 10℃ / min and holding for 2h, and finally heating to 800℃ at a heating rate of 15℃ / min and holding for 3h to obtain porous material". The other steps and parameters are the same, and will not be repeated in this comparative example. Finally, biochar was obtained and used in carbon dioxide adsorption experiments. It was found that the adsorption capacity of carbon dioxide under the same conditions was 3.0 mmol / g, which was lower than that in Application Example 3. This indicates that the eucalyptus biochar prepared by activation at 750℃ has better carbon dioxide adsorption performance, which may be due to its well-developed pore structure and suitable surface functional group distribution.

[0073] Performance testing:

[0074] The relevant properties of eucalyptus branches, bark, roots, and leaves were measured, and the results are shown in Tables 1-14 below:

[0075] Table 1. Factors and Levels Affecting Biochar Preparation Conditions

[0076]

[0077] Table 2 Response Surface Experimental Design

[0078]

[0079] Table 3 Performance test table of biochar prepared from eucalyptus branches 1.

[0080]

[0081] Table 4 Performance test table of biochar prepared from eucalyptus branches 1

[0082] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g) <!-- 6 -->]]> 1 9.5 541 0.036 77.027 2 9.8 519 0.003 3.299 3 8.65 434 0.059 122.161 4 5.22 490 0 0 5 7.82 518 0 0 6 8.74 276 0.009 21.277 7 7.76 121.5 0 0 8 9.51 453 0.021 38.505 9 9.48 416 0.018 39.739 10 7.31 126.6 0 0 11 9.13 194.1 0.014 36.777 12 9.48 191.3 0.094 220.148 13 9.05 142.9 0.058 133.11 14 9.86 677 0.057 120.43 15 9.97 638 0.027 56.929 16 6.82 268 0.045 108.763 17 9.58 411 0.052 100.346

[0083] Table 5 Performance test results of biochar prepared from eucalyptus branches 1

[0084]

[0085] Table 6 Performance Test Table of Biochar Prepared from Eucalyptus Branches 1

[0086] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 2.98802 149.837 2 3.78627 109.184 3 2.69266 223.294 4 18.21370 1.915 5 9.75552 8.962 6 3.99758 86.694 7 12.14430 2.22 8 3.76542 151.843 9 3.21688 165.556 10 17.14890 1.88 11 3.22079 153.22 12 2.35469 294.439 13 2.75244 238.143 14 2.71930 218.397 15 3.13068 137.318 16 2.04278 127.675 17 2.87652 200.299

[0087] Table 7 Performance Test Table of Biochar Prepared from Eucalyptus Branches 2

[0088]

[0089] Table 8 Performance Test Table of Biochar Prepared from Eucalyptus Branches 2

[0090] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 9.91 656 229.856 0.078 2 9.51 462 375.892 0.139 3 9.67 451 225.177 0.079 4 7.3 256 3.258 0 5 7.28 184.4 1.985 0 6 9.79 193.9 198.874 0.052 7 7.45 281 88.293 0.013 8 9.55 187.1 311.112 0.105 9 10.02 322 402.957 0.149 10 7.5 141.3 1.888 0 11 9.98 343 451.22 0.166 12 7.12 272 202.733 0.053 13 9.15 338 286.269 0.104 14 10.07 605 71.151 0.003 15 9.8 632 88.293 0.009 16 9.44 247 312.883 0.113 17 9.54 344 332.193 0.129

[0091] Table 9 Performance Test Table of Biochar Prepared from Eucalyptus Branches 2

[0092]

[0093] Table 10 Performance Test Table of Biochar Prepared from Eucalyptus Branches 2

[0094] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 0.1322 2.30062 2 0.1904 2.0259 3 0.1346 2.39046 4 1.29E-02 15.8467 5 8.30E-03 16.7175 6 1.50E-01 3.02015 7 0.09127 4.13495 8 1.68E-01 2.15391 9 1.90E-01 9.43032 10 0.004791 10.1512 11 1.94E-01 1.7187 12 0.1334 2.63234 13 0.164 2.29172 14 0.07406 4.16351 15 0.09127 4.13495 16 0.1699 2.17181 17 0.1729 2.08218

[0095] Table 11 Performance Test Table of Biochar Prepared from Eucalyptus Branches 3

[0096]

[0097] Table 12 Performance Test Table of Biochar Prepared from Eucalyptus Branches 3

[0098] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 9.67 603 0 0 2 9.8 693 0.008 19.897 3 9.93 505 0.123 282.675 4 6.8 115.9 0 0 5 7.54 128.4 0 0 6 9.69 566 0.124 311.33 7 7.84 138.7 0 0 8 9.77 563 0.125 291.093 9 9.84 579 0.138 319.017 10 7.94 194.5 0 0 11 9.66 503 0.104 249.27 12 10.07 435 0.137 330.281 13 8.31 480 0.069 163.899 14 9.99 1925 0 0 15 10.04 617 0.032 66.952 16 9.74 391 0.089 185.242 17 9.7 548 0.129 306.411

[0099] Table 13 Performance Test Table of Biochar Prepared from Eucalyptus Branches 3

[0100]

[0101] Table 14 Performance Test Table of Biochar Prepared from Eucalyptus Branches 3

[0102] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 4.37373 79.41 2 3.43962 44.891 3 2.18571 332.52 4 87.0623 2.097 5 13.7234 2.869 6 1.92593 358.789 7 14.2754 2.8 8 2.01515 341.745 9 2.01857 370.907 10 15.2131 2.828 11 2.10958 317.449 12 1.8971 371.736 13 2.43065 286.119 14 4.75508 58.959 15 3.05972 138.766 16 2.50188 278.645 17 1.94422 352.442

[0103] Table 15 Performance Test Table of Biochar Prepared from Eucalyptus Bark 1

[0104]

[0105] Table 16 Performance Test Table of Biochar Prepared from Eucalyptus Bark 1

[0106] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 10.37 282 0.000 0.000 2 10.15 297 0.005 8.932 3 8.97 169.5 0.037 72.994 4 5.87 363 0.000 0.000 5 5.92 327 0.000 0.000 6 8.69 164.4 0.046 101.046 7 7.43 299 0.000 0.000 8 8.65 161.2 0.030 58.903 9 8.7 156 0.015 31.824 10 6.1 325 0.000 0.000 11 8.53 136.6 0.002 8.327 12 8.25 259 0.026 50.582 13 8.5 153.3 0.025 51.246 14 10.5 317 0.000 0.000 15 10.24 256 0.001 2.049 16 8.68 1712 0.012 24.863 17 8.65 129.1 0.004 11.463

[0107] Table 17 Performance Test Table of Biochar Prepared from Eucalyptus Bark 1

[0108]

[0109] Table 18 Performance Test Table of Biochar Prepared from Eucalyptus Bark 1

[0110] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 14.1133 12.389 2 6.44349 36.385 3 3.33305 179.875 4 37.29 1.762 5 34.5095 1.733 6 2.90782 199.105 7 17.5777 3.388 8 3.34935 161.318 9 3.61677 148.883 10 23.7461 3.636 11 4.42639 70.591 12 3.16856 180.782 13 3.41517 163.702 14 13.1268 12.847 15 8.22697 22.386 16 3.73417 91.662 17 3.8134 114.524

[0111] Table 19 Performance Test Table of Biochar Prepared from Eucalyptus Bark 2

[0112]

[0113] Table 20 Performance Test Table of Biochar Prepared from Eucalyptus Bark 2

[0114] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 12.73 40.5 0.156 393.818 2 12.75 40.4 0.125 302.601 3 9.9 407 0.033 79.041 4 8.8 448 0.000 0.000 5 9.29 436 0.000 0.000 6 10.21 369 0.000 0.000 7 8.65 403 0.000 0.000 8 9.61 288 0.053 126.254 9 9.76 314 0.000 0.000 10 8.83 388 0.000 0.000 11 9.88 404 0.080 177.844 12 9.96 413 0.000 0.000 13 9.72 289 0.033 83.680 14 12.85 47.7 0.151 385.354 15 12.78 44.7 0.144 358.999 16 9.51 248 0.000 0.000 17 10.09 348 0.072 156.134

[0115] Table 21 Performance Test Table of Biochar Prepared from Eucalyptus Bark 2

[0116]

[0117] Table 22 Performance Test Table of Biochar Prepared from Eucalyptus Bark 2

[0118] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 1.93715 424.963 2 2.14716 341.868 3 3.03709 150.641 4 22.7511 3.256 5 24.93 3.438 6 7.21435 30.876 7 23.972 3.123 8 2.74577 197.937 9 6.21387 31.987 10 34.3536 1.761 11 2.62896 241.672 12 8.8271 21.305 13 3.00009 146.869 14 1.9391 414.686 15 2.0029 392.207 16 9.55275 16.222 17 2.64528 218.543

[0119] Table 23 Performance Test Table of Biochar Prepared from Eucalyptus Bark 3

[0120]

[0121] Table 24 Performance Test Table of Biochar Prepared from Eucalyptus Bark 3

[0122] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 12.79 296 0.010 27.789 2 12.74 305 0.002 4.437 3 10.01 30.9 0.097 257.060 4 8 21.7 0.000 0.000 5 8.51 1673 0.000 0.000 6 10.27 23 0.048 94.970 7 8.49 1795 0.000 0.000 8 10.15 21.8 0.068 151.326 9 10.12 22.8 0.035 76.916 10 9.17 1743 0.000 0.000 11 10.14 20.7 0.067 145.002 12 10.09 31.5 0.092 212.470 13 9.9 26.4 0.101 228.066 14 12.74 274 0.007 16.771 15 12.73 248 0.020 50.881 16 10.06 27.3 0.104 227.694 17 10.04 21.2 0.078 168.102

[0123] Table 25 Performance Test Table of Biochar Prepared from Eucalyptus Bark 3

[0124]

[0125] Table 26 Performance Test Table of Biochar Prepared from Eucalyptus Bark 3

[0126] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 3.88887 76.654 2 5.6246 35.241 3 2.05028 303.465 4 25.5547 2.415 5 27.617 2.397 6 3.01593 158.946 7 23.8441 2.660 8 2.60237 211.447 9 3.28321 141.264 10 18.0011 2.743 11 2.69511 209.409 12 2.30641 271.742 13 2.25201 279.742 14 4.49864 58.405 15 3.48423 96.757 16 2.2997 281.392 17 2.60381 231.868

[0127] Table 27 Performance Test Table of Biochar Prepared from Eucalyptus Root 1

[0128]

[0129] Table 28 Performance Test Table of Biochar Prepared from Eucalyptus Root 1

[0130] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 9.74 191.4 0.160 390.069 2 9.93 316 0.195 501.913 3 8.41 142.4 0.143 335.278 4 6.87 903 0.000 0.780 5 7.22 107.7 0.000 0.000 6 8.15 766 0.164 412.353 7 7.15 280.1 0.000 0.000 8 7.93 752 0.172 431.066 9 8.8 169.3 0.161 397.634 10 7.43 120.9 0.000 1.508 11 8.31 146.7 0.180 457.168 12 8.34 149.2 0.168 422.523 13 6.95 871 0.191 490.668 14 9.98 269 0.201 518.774 15 9.31 249 0.152 379.719 16 7.71 138.5 0.188 470.034 17 7.81 100.6 0.155 375.582

[0131] Table 29 Performance Test Table of Biochar Prepared from Eucalyptus Root 1

[0132]

[0133] Table 30 Performance Test Table of Biochar Prepared from Eucalyptus Root 1

[0134] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 1.86E+00 422.403 2 1.68020 518.006 3 2.0005 380.259 4 14.6584 2.107 5 20.2553 1.855 6 1.79518 451.612 7 24.2747 1.909 8 1.77604 459.871 9 1.8653 441.839 10 10.5733 2.453 11 8.68783 485.909 12 1.81376 459.283 13 1.69092 514.636 14 1.69023 539.435 15 1.86E+00 416.742 16 1.76277 499.170 17 1.94788 426.184

[0135] Table 31 Performance Test Table of Biochar Prepared from Eucalyptus Roots 2

[0136]

[0137] Table 32 Performance Test Table of Biochar Prepared from Eucalyptus Roots 2

[0138] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 9.31 256 0.063 136.044 2 9.14 256 0.129 282.601 3 8.04 120.5 0.149 368.412 4 7.72 793 0.000 0.000 5 8.1 110.7 0.000 0.000 6 8.14 736 0.154 380.080 7 8.02 150.1 0.000 0.000 8 8.18 137.6 0.152 377.895 9 8.12 123.4 0.162 408.690 10 8.32 123.5 0.000 0.000 11 7.97 140.3 0.089 197.949 12 8.03 655 0.144 335.279 13 7.91 118.5 0.111 251.164 14 10.08 304 0.146 365.401 15 9.81 299 0.186 473.681 16 8.33 755 0.162 404.860 17 7.88 110.2 0.163 408.851

[0139] Table 33 Performance Test Table of Biochar Prepared from Eucalyptus Roots 2

[0140]

[0141] Table 34 Performance Test Table of Biochar Prepared from Eucalyptus Roots 2

[0142] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 2.70198 228.408 2 2.16832 324.384 3 1.89459 406.295 4 16.5342 2.244 5 18.003 2.856 6 1.8561 408.668 7 18.3057 2.657 8 1.85121 413.152 9 1.76802 431.229 10 26.505 2.571 11 2.44905 275.588 12 2.02043 388.601 13 2.25305 331.647 14 1.8546 390.073 15 1.74712 492.231 16 1.7792 430.849 17 1.77482 430.816

[0143] Table 35 Performance Test Table of Biochar Prepared from Eucalyptus Root 3

[0144]

[0145] Table 36 Performance Test Table of Biochar Prepared from Eucalyptus Roots 3

[0146] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 9.34 1589 0.162 410.697 2 9.69 192.2 0.072 164.446 3 9.12 166.3 0.144 337.548 4 6.94 979 0.000 0.000 5 7.62 111.5 0.000 0.000 6 9.16 182.3 0.160 394.967 7 7.5 289 0.000 0.000 8 8.31 145.9 0.156 379.294 9 7.84 138.3 0.104 230.087 10 7.95 74.4 0.000 0.000 11 9.05 174.5 0.165 410.711 12 9 143.5 0.158 391.900 13 8.57 157.2 0.162 400.882 14 10.04 257 0.058 114.755 15 9.62 281 0.176 449.719 16 8 147.9 0.163 412.327 17 9 179.8 0.148 361.258

[0147] Table 37 Performance Test Table of Biochar Prepared from Eucalyptus Root 3

[0148]

[0149] Table 38 Performance Test Table of Biochar Prepared from Eucalyptus Roots 3

[0150] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 1.75531 430.514 2 2.45647 244.550 3 2.0315 383.338 4 24.9078 3.293 5 32.9682 1.814 6 1.80188 417.439 7 17.2958 1.971 8 1.94121 420.153 9 2.43162 317.399 10 20.3796 1.994 11 1.84453 442.128 12 1.85522 424.083 13 1.81419 425.543 14 2.84111 218.799 15 1.72545 461.623 16 1.77543 436.475 17 1.89271 398.831

[0151] Table 39 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 1

[0152]

[0153] Table 40 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 1

[0154] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 10.32 118.8 0 0 2 10.3 122.5 0.008 19.897 3 10.37 87.3 0.123 282.675 4 7.9 39.5 0 0 5 7.75 48.4 0 0 6 10.18 121.7 0.124 311.33 7 8.3 47.5 0 0 8 10.59 91.5 0.125 291.093 9 10.44 111.5 0.138 319.017 10 7.19 56.6 0 0 11 10.19 96.1 0.104 249.27 12 10.49 66.7 0.137 330.281 13 10.2 96.9 0.069 163.899 14 10.3 122.5 0 0 15 10.16 94.5 0.032 66.952 16 9.75 135.5 0.089 185.242 17 9.8 131.5 0.129 306.411

[0155] Table 41 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 1

[0156]

[0157] Table 42 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 1

[0158] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 4.37373 79.41 2 3.43962 44.891 3 2.18571 332.52 4 87.0623 2.097 5 13.7234 2.869 6 1.92593 358.789 7 14.2754 2.8 8 2.01515 341.745 9 2.01857 370.907 10 15.2131 2.828 11 2.10958 317.449 12 1.8971 371.736 13 2.43065 286.119 14 4.75508 58.959 15 3.05972 138.766 16 2.50188 278.645 17 1.94422 352.442

[0159] Table 43 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 2

[0160]

[0161] Table 44 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 2

[0162] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 10.44 173.7 0.010 22.172 2 10.24 137.9 0.002 4.815 3 10.23 113.6 0.000 0.000 4 8.05 50.4 0.000 0.000 5 8.09 43.3 0.000 0.000 6 10.02 90.9 0.000 0.700 7 7.88 47.6 0.000 0.000 8 9.93 100.6 0.000 0.783 9 10.16 140.5 0.000 0.000 10 8.04 49.3 0.000 0.000 11 10.18 91.9 0.000 1.047 12 9.86 140.6 0.000 0.000 13 10.54 98.3 0.000 0.000 14 10.23 147.5 0.000 0.000 15 10.16 140.6 0.000 0.000 16 10.46 122.7 0.000 0.000 17 10.36 82.1 0.000 0.849

[0163] Table 45 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 2

[0164]

[0165] Table 46 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 2

[0166] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 3.91931 37.217 2 8.60332 8.238 3 3.2738 1.579 4 22.2234 2.062 5 27.4839 1.487 6 22.5044 1.648 7 22.7613 1.943 8 19.7964 2.276 9 25.8343 2.137 10 24.4284 1.648 11 20.7607 2.283 12 35.5077 1.674 13 25.5177 2.748 14 12.5544 8.130 15 12.5849 3.828 16 25.8300 2.876 17 21.6299 1.977

[0167] Table 47 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 3

[0168]

[0169] Table 48 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 3

[0170] Run PH Electrical conductivity (µs / cm) Micropore volume (cc / g) <![CDATA[Micropore area (m 2 / g)]]> 1 10.42 198 0.001 1.664 2 10.56 185.5 0.014 33.732 3 10.57 118.9 0.001 3.392 4 7.41 75 0.000 0.000 5 8.11 40.6 0.000 0.000 6 10.28 110.4 0.000 1.335 7 8.18 49.9 0.000 0.000 8 10.6 97.1 0.000 0.952 9 10.67 92.6 (-0.000) 0.031 10 7.61 63.6 0.000 0.000 11 10.6 123.1 0.001 2.314 12 10.59 91.6 0.001 2.661 13 10.62 133.4 0.000 1.051 14 10.37 171.2 0.007 16.011 15 10.31 178.4 0.000 0.437 16 9.99 186.2 0.001 2.115 17 10.43 145.6 0.001 2.577

[0171] Table 49 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 3

[0172]

[0173] Table 50 Performance Test Table of Biochar Prepared from Eucalyptus Leaves 3

[0174] Run Average pore size (nm) <![CDATA[Specific surface area (m 2 / g)]]> 1 4.28483 24.041 2 3.09713 72.933 3 10.109 7.910 4 18.725 1.183 5 28.5971 1.305 6 26.4716 1.077 7 18.887 1.214 8 25.6539 1.763 9 0.01132 1.942 10 85.8033 1.726 11 23.0321 2.551 12 101.017 2.562 13 11.9841 6.123 14 3.53983 37.181 15 2.89052 1.309 16 21.6175 1.621 17 21.2957 2.721

[0175] This invention utilizes hydrothermal carbonization pretreatment combined with a KOH segmented activation process (350℃→550℃→750℃) to produce biochar with a high specific surface area, forming a rich microporous structure (pore size 0.5-2.0nm accounting for >80%), providing ample sites for pollutant adsorption.

[0176] Magnetron sputtering modification introduces nitrogen functional groups (such as pyridine nitrogen and pyrrole nitrogen) to form Lewis acid sites, thereby enhancing the chemical adsorption capacity for CO2.

[0177] By utilizing forestry waste such as eucalyptus bark and branches (accounting for 80%-90%), combined with agricultural waste such as rice husks (10%-20%), the goal of "treating waste with waste" can be achieved, reducing raw material costs while minimizing pollution from burning agricultural and forestry waste.

[0178] The segmented heat preservation process (total heat preservation time 6h) saves 20% more energy than the traditional single high-temperature pyrolysis, and the KOH catalyst can be recycled, reducing the emission of chemical waste.

[0179] Outstanding performance across multiple fields:

[0180] Acid soil improvement: For eucalyptus forest soils with a pH of 5.3-6.96, an application rate of 4%-6% can increase soil pH, cation exchange capacity, available phosphorus content, promote the increase of microbial biomass phosphorus, and significantly improve soil fertility;

[0181] Deep desulfurization of fuel oil: the adsorption capacity of dibenzothiophene (DBT) reached 172.5 mg / g (Example 1), which meets the environmental protection requirement of fuel oil sulfur content <10 ppm;

[0182] CO2 adsorption and catalysis: In simulated flue gas (10% CO2), the CO2 concentration decreased to 5% within 5 hours. Combined with the catalytic effect of nitrogen functional groups, the CO2 cycloaddition reaction can be promoted simultaneously, with a conversion rate of 58% (Application Example 4).

[0183] Data Analysis:

[0184] Structure-performance synergistic optimization: segmented activation forms a pore structure of "micropores as the main component (70%) + mesopores as the auxiliary component", which increases the specific surface area by 100%-200% compared with traditional biochar and increases the adsorption site density by 3 times.

[0185] Raw material and process innovation: The utilization rate of eucalyptus waste reaches over 90%, and the magnetron sputtering modification technology achieves uniform loading of functional groups (nitrogen content is increased by 20 times compared to unmodified products), avoiding the unevenness problem of traditional acid and alkali soaking.

[0186] Multi-scenario adaptability: It performs well in acidic soil (pH 5.0-6.5), fuel oil (simulated oil / actual diesel), and flue gas (moisture content 5%-10%), and has a wide range of applications;

[0187] In summary, this patent achieves multiple breakthroughs in the structure, performance, and environmental friendliness of eucalyptus biochar through process innovation and raw material optimization. The data fully supports its efficient application in soil remediation, energy purification, and carbon capture.

[0188] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0189] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method of preparing biochar based on eucalyptus, characterized by, The method comprises the following steps: Step S1. Raw material pretreatment: the eucalyptus raw material is crushed and dried at 65℃ for 24h to obtain a raw material; Step S2. Pyrolysis treatment: the dried raw material is placed in an OTL1600 tube furnace by high-temperature pyrolysis to obtain a pore material; Step S3. Cooling and collection: the pore material is naturally cooled to room temperature and ground to 100 mesh to obtain biochar; The eucalyptus raw material is crushed and dried in step S1, then treated with an acid solution, and finally subjected to hydrothermal carbonization to obtain a raw material; In step S2, the high-temperature pyrolysis process for treating the raw material is as follows: a catalyst is added to the raw material, nitrogen is used as the protective gas, and a stepwise heat preservation process is used for heat preservation to obtain a pore material; The catalyst is KOH, and the mass ratio of the raw material to the catalyst is 1:3; the stepwise heat preservation process is as follows: first, heat to 350℃ at a heating rate of 5℃ / min and keep for 1h, then heat to 550℃ at a heating rate of 10℃ / min and keep for 2h, and finally heat to 750℃ at a heating rate of 15℃ / min and keep for 3h; The eucalyptus raw material in step S1 includes eucalyptus material and agricultural waste; The mass ratio of the eucalyptus material to the agricultural waste in step S1 is 30-40:10-15; The particle size of the crushed eucalyptus material in step S1 is 2-5mm; The eucalyptus material is any one or several of eucalyptus bark, eucalyptus branches, eucalyptus roots and eucalyptus leaves; The agricultural waste is any one of rice husk and corn stalk.

2. The method of claim 1, wherein the eucalyptus is Eucalyptus tereticornis. The acid used in the acid solution treatment process is a 5% sulfuric acid solution; The temperature of the hydrothermal carbonization is 180℃, and the hydrothermal carbonization time is 18h.

3. The method of claim 1, wherein the eucalyptus is Eucalyptus tereticornis. The pore material in step S3 is subjected to surface functionalization modification before grinding, and the process of surface functionalization modification is as follows: the pore material is subjected to magnetron sputtering modification; Nitrogen plasma is used for magnetron sputtering during the magnetron sputtering modification.

4. Use of biochar prepared from eucalyptus, characterized in that, The biochar is prepared by the preparation method of any one of claims 1-3, and is used for preparing a biochar-based fertilizer and for soil phosphorus regulation.

5. Use of biochar prepared from eucalyptus, characterized in that, The biochar is prepared by the preparation method of any one of claims 1-3, and is used for desulfurization.

6. Use of biochar prepared from eucalyptus, characterized in that, The biochar is prepared by the preparation method of any one of claims 1-3, and is used for CO2 adsorption and catalysis.

Images