• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a method for remedying impoverished soil, belongs to the technical field of soil remediation, and solves the problems that an existing 5 greenhouse planting soil impoverishment treatment method is high in economical cost and cannot meet the requirement of greenhouse planting on land. The method for remedying impoverished soil of the present invention includes: step 1, crushing agricultural waste biomass; step 2, performing hydrothermal carbonization on the crushed agricultural waste biomass and water to obtain solid-state hydrochar and 10 hydrochar liquid; step 3, preparing eutrophic hydrochar, step 4, preparing porous biochar through microwave carbonization, and step 5, proportionally mixing the hydrochar, the eutrophic hydrochar and the porous biochar to obtain an impoverished soil improving agent, and adding the impoverished soil improving agent into impoverished soil for remedying the soil. The present invention achieves the effect of 15 soil quality and efficiency improving by proportionally adding the hydrochar, the eutrophic hydrochar and the porous biochar into the impoverished soil.
    公开号:NL2029868A
    申请号:NL2029868
    申请日:2021-11-23
    公开日:2022-01-13
    发明作者:Wang Chongqing；Cao Yijun
    申请人:Univ Zhengzhou；
    IPC主号:
    专利说明:

    METHOD FOR REMEDYING IMPOVERISHED SOIL
    TECHNICAL FIELD The present invention relates to the technical field of soil remediation, and more particularly relates to a method for remedying impoverished soil.
    BACKGROUND Agriculture is the basis for social development and progress. With the social development, the agriculture has changed greatly, for example, chemical fertilizers and pesticides are widely applied. In order to meet the requirements of rapid and diversified social development, greenhouse planting of fruits and vegetables becomes more and more extensive. As for the greenhouse planting process, under constant heavy cropping and with heavy use of fertilizers and pesticides, the soil is excessively used and become impoverished, and the soil hardening, salinization and fertilizer efficiency reduction are aggravated. After the greenhouse planting for a certain time, the land soil is impoverished, and the greenhouse crop planting is difficult to continue. The treatment manners at present are generally as follows: soil replacement, 1.e., the impoverished soil is covered with high- quality soil from other places for continuous planting; and the cropping on the land is stopped for a certain time after the greenhouse planting for a certain time, so that the greenhouse planting can be continued after the impoverished soil is gradually recovered. By adopting the first manner, a great amount of high-quality soil is needed, the economic cost is higher, and the soil impoverishment problem is not solved. By adopting the second manner, a long time is needed, and the requirement of the greenhouse planting on the land is difficult to meet. How to condition the greenhouse planting soil to achieve continuous proceeding of greenhouse planting is a problem to be solved at present.
    SUMMARY In view of the above analysis, the present invention aims at providing a method for remedying impoverished soil so as to solve the problems that an existing greenhouse planting soil impoverishment treatment method is high in economical cost and cannot meet the requirement of greenhouse planting on land.
    The objective of the present invention is mainly achieved through the following technical solution: The present invention provides a method for remedying impoverished soil, including the following steps: step 1, crushing agricultural waste biomass; step 2, performing hydrothermal carbonization on the crushed agricultural waste biomass and water, performing solid-liquid separation on a hydrothermal carbonization product to obtain solid-state hydrochar and hydrochar liquid, and recycling the hydrochar liquid, step 3, preparing eutrophic hydrochar from part of the solid-state hydrochar; step 4, dissolving part of the solid-state hydrochar in step 2 and an activating agent into water to obtain a mixture, heating the mixture while stirring until moisture in the mixture is completely volatilized, preparing porous biochar through microwave carbonization, washing and drying the hydrochar to obtain porous biochar, wherein a microwave power during microwave carbonization is 500 to 800 W, a microwave carbonization time is 4 to 10 min, and a microwave carbonization atmosphere is isolated air, nitrogen gas or argon gas; and step 5, proportionally mixing the hydrochar prepared in step 2, the eutrophic hydrochar prepared in step 3 and the porous biochar prepared in step 4 to obtain an impoverished soil improving agent, and adding the impoverished soil improving agent into impoverished soil for remedying the soil.
    Further, in step 1, the agricultural waste biomass includes straw, wood chips, fallen leaves, crop waste and livestock manure, and a particle diameter of the crushed agricultural waste biomass is less than 0.18 mm.
    Further, in step 2, a mass ratio of the biomass to the water in the hydrothermal carbonization process is 1:1-1:4, a hydrothermal carbonization temperature is 180 to 300°C, a hydrothermal carbonization time is 60 to 360 min, and a solid-liquid separation manner is mechanical filtration or centrifugal separation.
    Further, in step 4, a drying temperature of the hydrochar is 60 to 100°C, and a moisture content of the dried hydrochar is less than 5%.
    Further, in step 4, the activating agent is one of sodium hydroxide, potassium hydroxide and phosphoric acid; and a heating temperature in a stirring process of an activating agent solution is lower than 100°C.
    Further, in step 4, a washing medium of the biochar is water, and a pH value of the washed biochar is 6.5 to 7.5, a drying temperature is 80 to 120°C, and a drying time is 300 to 600 min.
    Further, in step 5, a mass ratio of the hydrochar to the eutrophic hydrochar to the porous biochar is 1:0.5 1:0.4 0.8, and an addition amount into the impoverished soil is 3% to 10%.
    Further, in step 3, a method for preparing the eutrophic hydrochar includes the following steps: step 1, adding the hydrochar into a nutrition solution with a concentration of 500 to 1500 mg/L, performing sufficient stirring to separate out hydrochar, and drying the hydrochar at a temperature below 70°C to obtain the dried hydrochar; step 11, adding urea into a granulator, spraying a bonding agent, and then adding the dried hydrochar for granulation forming; and step iii, continuously spraying the bonding agent into the granulator, then, adding the dried hydrochar for granulation forming, and repeating the step according to particle diameter requirements to finally obtain the eutrophic hydrochar with a particle diameter of 0.5 to 1.0 mm.
    Further, in step it, a particle diameter of the urea is 0.074 to 0.1 mm, and the bonding agent is a polyvinyl alcohol water solution with a mass concentration of 3.0 to 10.0%; and a mass ratio of the hydrochar to the urea is 1:4 10, and a particle diameter after the forming is 0.2 to 0.4 mm.
    Further, in step 1, the nutrition solution is one or more of monopotassium phosphate, ammonium dihydrogen phosphate, magnesium phosphate and calcium superphosphate. Compared with the related art, the present invention may achieve at least one of the following beneficial effects: (1) In an aspect of raw materials, the agricultural waste biomass raw materials used by the present invention are cheap in price, wide in resources, renewable and environmental-friendly. The waste biomass is subjected to hydrothermal carbonization treatment, and the wet waste biomass can be directly treated through hydrothermal carbonization, and the drying process of the waste biomass is avoided.
    (2) In the hydrothermal carbonization process, part of components of the agricultural waste biomass is thermally decomposed, an ash content (mineral substances) in the biomass enters the hydrochar liquid, and the salt and alkali content increase during hydrochar addition into the soil can be further avoided.
    The present invention can convert the agricultural waste biomass into the hydrochar containing a great number of functional groups on the surface, and the hydrochar can effectively improve the salinity and alkalinity of the impoverished soil due to the weak acidity of the hydrochar.
    Most contents of the biomass are organic carbohydrates (90% or above), and a small number of mineral substances are also contained (generally less than 5%), such as silicon, calcium and magnesium salts.
    In the hydrothermal carbonization process, the mineral substance (or referred to as ash contents) in the biomass may enter a liquid phase, and the organic carbohydrates are converted into the hydrochar. (3) The surface of the solid-state hydrochar prepared by the present invention contains a great number of functional groups, the surface functional groups are favorable for immobilizing nutrients such as nitrogen, phosphorus, potassium and magnesium into the solid-state hydrochar through chemical effects during preparation of the eutrophic hydrochar, and the slow release effect of the nutrients is increased.
    The prepared eutrophic hydrochar has a multilayer structure.
    By taking the urea as a nitrogen fertilizer that is wrapped in the cores of the eutrophic hydrochar particles, the fertilizer efficiency slow release effect can be obviously improved. (4) The present invention uses the hydrochar as raw materials to perform microwave carbonization, the hydrochar reacts with the activating agent, and the large-specific- area porous biochar of the porous structure can be favorably prepared.
    Through the microwave carbonization, the porous biochar can be fast prepared.
    By adding the porous biochar into the impoverished soil, the soil voids and air permeability can be effectively increased, and the easy-to-harden property of the impoverished soil is improved.
    In the present invention, the technical solutions can be mutually combined to achieve more preferable combination solutions.
    Other characteristics and advantages of the present invention will be illustrated in the following descriptions.
    Additionally, part of advantages can be apparent from the description, or can be known through implementing the present invention.
    The objective and other advantages of the present invention can be realized and achieved through embodiments in the description and contents specially pointed out in the drawings.
    BRIEF DESCRIPTION OF THE DRAWINGS 5 The accompanying drawings are merely intended to show specific embodiments and are not constructed as a limitation to the present invention, and the same reference numerals are used to represent the same components throughout the accompanying drawings. FIG. 1 is a schematic flow diagram of a method for remedying impoverished soil.
    FIG. 2 is a scanning electron microscope photograph of a large-specific-surface-area porous biochar. FIG. 3 is an infrared spectrogram of hydrochar.
    DETAILED DESCRIPTION Exemplary embodiments of the present invention are described in detail with reference to accompanying drawings. The accompanying drawings constitute a part of the present invention and explain the principles of the present invention together with the embodiments of the present invention, but are not intended to limit the scope of the present invention.
    The present invention provides a method for remedying impoverished soil, including the following steps: step 1, crushing agricultural waste biomass; Step 2, the crushed agricultural waste biomass and water are subjected to hydrothermal carbonization, a hydrothermal carbonization product is subjected to solid-liquid separation to obtain solid-state hydrochar and hydrochar liquid, and the hydrochar liquid 1s recycled. Step 3, eutrophic hydrochar is prepared from part of the solid-state hydrochar in step 2. Step 4, part of the solid-state hydrochar in step 2 and an activating agent are dissolved into water to obtain a mixture, the mixture is heated while stirring until moisture in the mixture is completely volatilized, microwave carbonization is performed at a microwave power of 500 to 800 W for a microwave carbonization time of 4 to 10 min in a microwave carbonization atmosphere of isolated air (sealed), nitrogen gas or argon gas, and after the microwave carbonization, the obtained biochar is washed and dried to obtain porous biochar. Step 5, the hydrochar prepared in step 2, the eutrophic hydrochar prepared in step 3 and the porous biochar prepared in step 4 are proportionally and uniformly mixed to obtain an impoverished soil improving agent, and then, the impoverished soil improving agent is added into impoverished soil for remedying the soil. Compared with the prior art, the method for remedying impoverished soil provided by the present invention has the advantages that available resources are rich, the cost is low, the renewable agricultural waste biomass is used as raw materials, the hydrothermal carbonization has low requirements on the humidity of the waste biomass raw material, the drying process of the waste biomass is reduced, and the solid-state hydrochar obtained through hydrothermal carbonization has low ash content and rich surface functional groups; the eutrophic hydrochar prepared from the solid- state hydrochar has good fertilizer efficiency and slow release effects; the porous biochar prepared from the solid-state hydrochar has the characteristics of porosity and large specific surface area (as shown in FIG. 2), and the soil improving agent proportionally prepared from the solid-state hydrochar, the eutrophic hydrochar and the porous biochar can obviously improve the characteristics of salinity and alkalinity, easy hardening, few nutrients and the like of the impoverished soil.
    In step 1, the agricultural waste biomass includes straw, wood chips, fallen leaves, crop waste and livestock manure, and a particle diameter of the crushed agricultural waste biomass is less than 0.18 mm.
    In step 2, a mass ratio of the waste biomass to the water in the hydrothermal carbonization process is 1:1-1:4, a hydrothermal carbonization temperature is 180 to 300°C, a hydrothermal carbonization time is 60 to 360 min, and a solid-liquid separation manner is mechanical filtration or centrifugal separation. A yield of the hydrochar 1s 30% to 75%, and a charcoal content in the hydrochar is 10% to 50% (a calculation process of the yield of the hydrochar is as follows: the mass of the waste biomass before the hydrothermal carbonization is divided by the mass of the hydrochar obtained after the hydrothermal carbonization, and then the obtained value is multiplied with 100%. The charcoal content is measured by an elemental analyzer).
    In step 2, the hydrothermal carbonization condition is controlled within the above range, so as to ensure that the hydrochar favorable for the subsequent use effect is obtained, and the infrared spectrogram of the hydrochar is as shown in FIG. 3. It should be noted that when the hydrochar liquid is cycled, the moisture therein can conduct a hydrothermal carbonization process together with the waste biomass. In step 4, a drying temperature of the hydrochar is 60 to 100°C, and a moisture content of the dried hydrochar is less than 5%. The activating agent is one of sodium hydroxide, potassium hydroxide and phosphoric acid, and a mass ratio of the hydrochar to the activating agent is 1:0.5 2, and the heating temperature in the stirring process in an activating agent solution is 100°C. A mass ratio of the hydrochar to the activating agent is 1:0.5 2, and the large-specific-surface-area porous biochar (the specific surface area is 500 to 1500 m2/g) of a porous structure is mainly obtained through the reaction of the activating agent with the hydrochar in the carbonization process, as shown in FIG. 2.
    In step 4, a microwave power is 500 to 800 W, a microwave carbonization time is 4 to 10 min, and a microwave carbonization atmosphere is isolated air (sealed), nitrogen gas or argon gas. According to an existing carbonization method, temperature rise carbonization is performed in a tubular furnace. Compared with the existing carbonization manner, the present invention has the advantages that the carbonization time of the microwave carbonization is obviously reduced (reduced to 5 to 10 min from 4 to 7 h), the microwave carbonization is different from the tubular furnace carbonization heating manner, through microwaves generated by the microwave carbonization adopted by the present invention, the uniform temperature rise inside and outside the solid materials can be achieved, and the porous biochar material can be favorably and fast prepared.
    The microwave carbonization atmosphere is controlled into isolated air (sealed), nitrogen gas or argon gas atmosphere, so that the carbonization process can be better controlled to obtain the biochar with the relatively uniform pore diameter structure. If the atmosphere is not controlled to cause the air introduction in the carbonization process or the oxidization, the charcoal combustion easily occurs in the carbonization process, which results that the yield of the porous biochar is reduced, and the porous biochar is not uniform.
    In step 4, a washing medium of the biochar is water, and a pH value of the washed biochar is 6.5 to 7.5, a drying temperature is 80 to 120°C, and a drying time is 300 to 600 min. Since the biochar is prepared through acid or alkali activation, after carbonization, the biochar has strong acidity or strong alkalinity, and needs to be washed to be neutral with water.
    In step S, a mass ratio of the hydrochar to the eutrophic hydrochar to the porous biochar is 1:0.5 1:0.4 0.8, and an addition amount into the impoverished soil is 3% to 10%. In step 3, a method for preparing the eutrophic hydrochar includes the following steps: Step 1, the solid-state hydrochar is added into a nutrition solution and uniformly stirred, solid-state hydrochar is separated out, and dried to obtain dry hydrochar. The solid- state hydrochar is added into the nutrition solution, the hydrochar can adsorb substances in the solution so that nutrients such as phosphorus, potassium, nitrogen and magnesium can be attached to the surface of the hydrochar to increase the fertilizer efficiency of the hydrochar. In step i, the nutrition solution is one or more of monopotassium phosphate, ammonium dihydrogen phosphate, magnesium phosphate and calcium superphosphate. A concentration of the nutrition solution is 500 to 1500 mg/L, and the drying temperature of the hydrochar is below 70°C.
    Step ii, urea is added into a granulator, a certain amount of bonding agent is sprayed, and then, a certain amount of dried hydrochar is added for granulation forming. In step it, a particle diameter of the urea is 0.074 to 0.1 mm, and the bonding agent is a polyvinyl alcohol water solution with a mass concentration of 3.0 to 10.0%; and a mass ratio of the hydrochar to the urea is 1:4 10, and a particle diameter after the forming is 0.2 to 0.4 mm. Step ii1, a certain amount of the bonding agent is continuously sprayed into the granulator, then, a certain amount of the dried hydrochar is added for granulation forming, and the step is repeated according to particle diameter requirements of the eutrophic hydrochar to finally obtain the multilayer granular eutrophic hydrochar. In step iil, the particle diameter of the formed eutrophic hydrochar is 0.5 to 1.0 mm. By controlling the particle diameter of the eutrophic hydrochar within this range, the slow release effect of the fertilizer efficiency of the eutrophic hydrochar can be ensured.
    The total nutrient content of the eutrophic hydrochar prepared by the present invention is 20% to 50%, the accumulated release rate of the nutrients in 30 d is less than 60%, and the slow release effect of a slow release fertilizer is good. Embodiment 1 The present embodiment provides a method for remedying impoverished soil, including the following steps: Step 1, agricultural waste biomass including straw, wood chips, fallen leaves, crop waste and livestock manure was crushed, and a particle diameter of the crushed agricultural waste biomass was 0.17 mm.
    Step 2, the crushed agricultural waste biomass and water were subjected to hydrothermal carbonization, a mass ratio of the biomass to the water in the hydrothermal carbonization process was 1:1, a hydrothermal carbonization temperature was 180°C, a hydrothermal carbonization time was 59 min, a hydrothermal carbonization product was subjected to solid-liquid separation in a mechanical filtration or centrifugal separation manner to obtain solid-state hydrochar and hydrochar liquid, and the hydrochar liquid was recycled.
    Step 3, eutrophic hydrochar was prepared from part of the solid-state hydrochar according to a preparation method of the eutrophic hydrochar including the following steps: Step i, the hydrochar was added into a nutrition solution of monopotassium phosphate with a concentration of 500 mg/L and uniformly stirred, hydrochar was separated out, and dried at a temperature of below 69°C to obtain dry hydrochar.
    Step 11, urea was added into a granulator, a polyvinyl alcohol water solution with a mass concentration of 3.0% was sprayed, and then, the dried hydrochar was added for granulation forming. The particle diameter of the urea was 0.074 mm, a mass ratio of the hydrochar to the urea was 1:4, and a particle diameter after the forming was 0.2 mm.
    Step 111, the bonding agent was continuously sprayed into the granulator, then, the dried hydrochar was added for granulation forming, and the step was repeated according to particle diameter requirements to finally obtain the eutrophic hydrochar with the particle diameter of 0.5 mm.
    Step 4, part of the solid-state hydrochar in step 2 and sodium hydroxide were dissolved into water to obtain a mixture, the mixture is heated while stirring until moisture in the mixture was completely volatilized, microwave carbonization was performed at a microwave power of 500 W for a microwave carbonization time of 4 min in a microwave carbonization atmosphere of isolated air (sealed), nitrogen gas or argon gas, and after the microwave carbonization, the obtained biochar was washed and dried to obtain porous biochar. The drying temperature of the hydrochar was 59°C, and after drying, the moisture of the hydrochar was less than 4%. A heating temperature in the stirring process in a sodium hydroxide solution was 98°C. A washing medium of the biochar was water, and a pH value of the washed biochar was 6.5, a drying temperature was 80°C, and a drying time was 300 min.
    Step 5, the hydrochar prepared in step 2, the eutrophic hydrochar prepared in step 3 and the porous biochar prepared in step 4 were mixed according to a mass proportion of 1:0.5:0.8 to obtain an impoverished soil improving agent, and then, the impoverished soil improving agent was added into impoverished soil for remedying the soil. The addition amount of the improving agent was 4%. The soil improving agent was added into the greenhouse planting impoverished soil, the surface layer impoverished soil in a greenhouse was shallowly cultivated by using a ploughing machine, so that the soil improving agent spread onto the ground surface could be buried into the shallow layer soil, and the improved soil in the planting greenhouse is obtained. The porosity of the improved soil was increased by 2%, the water holding performance was increased by 5%, and the organic carbon content was increased by
    3.8%.
    According to a first group of experiments, ryegrass was respectively planted in the impoverished soil and the improved soil. Through dry weight comparison of the ryegrass after 15-day growth, the growth speed of the ryegrass planted in the improved soil prepared by the present invention was improved by 20%.
    According to a second group of experiments, vegetables (Chinese cabbages) were respectively planted in the impoverished soil and the improved soil. In comparison with that of vegetables planted in the impoverished soil, the yield of the vegetables planted in the improved soil prepared by the present invention was improved by 25%.
    Embodiment 2 The present embodiment provides a method for remedying impoverished soil, including the following steps:
    Step 1, agricultural waste biomass including straw, wood chips, fallen leaves, crop waste and livestock manure was crushed, and a particle diameter of the crushed agricultural waste biomass was less than 0.15 mm.
    Step 2, the crushed agricultural waste biomass and water were subjected to hydrothermal carbonization, a mass ratio of the biomass to the water in the hydrothermal carbonization process was 1:3, a hydrothermal carbonization temperature was 240°C, a hydrothermal carbonization time was 240 min, a hydrothermal carbonization product was subjected to solid-liquid separation in a mechanical filtration or centrifugal separation manner to obtain solid-state hydrochar and hydrochar liquid, and the hydrochar liquid was recycled.
    Step 3, eutrophic hydrochar was prepared from part of the solid-state hydrochar according to a preparation method of the eutrophic hydrochar including the following steps: Step 1, the hydrochar was added into an ammonium dihydrogen phosphate solution with a concentration of 1000 mg/L to be uniformly stirred, hydrochar was separated out, and drying was performed under the condition below 65°C to obtain dry hydrochar.
    Step ii, urea was added into a granulator, a polyvinyl alcohol water solution with a mass concentration of 8.0% was sprayed, and then, the dried hydrochar was added for granulation forming.
    The particle diameter of the urea was 0.09 mm, a mass ratio of the hydrochar to the urea was 1:7, and a particle diameter after the forming was 0.3 mm.
    Step iit, the bonding agent was continuously sprayed into the granulator, then, the dried hydrochar was added for granulation forming, and the step was repeated according to particle diameter requirements to finally obtain the eutrophic hydrochar with the particle diameter of 0.8 mm.
    Step 4, part of the solid-state hydrochar in step 2 and potassium hydroxide were dissolved into water to obtain a mixture, the mixture is heated while stirring until moisture in the mixture was completely volatilized, microwave carbonization was performed at a microwave power of 700 W for a microwave carbonization time of 7 min in a microwave carbonization atmosphere of isolated air (sealed), nitrogen gas or argon gas, and after the microwave carbonization, the obtained biochar was washed and dried to obtain porous biochar.
    The drying temperature of the hydrochar was 85°C,
    and after drying, the moisture of the hydrochar was 4%. A heating temperature in the stirring process in a potassium hydroxide solution was 90°C. A washing medium of the biochar was water, and a pH value of the washed biochar was 6.9, a drying temperature was 100°C, and a drying time was 450 min.
    Step 5, the hydrochar prepared in step 2, the eutrophic hydrochar prepared in step 3 and the porous biochar prepared in step 4 were mixed according to a mass proportion of 1:0.7:0.6 to obtain an impoverished soil improving agent.
    According to this embodiment, the soil improving agent was added into the greenhouse planting impoverished soil according to a mass ratio of 8%, the surface layer impoverished soil in a greenhouse was shallowly cultivated by using a ploughing machine, so that the soil improving agent spread onto the ground surface could be buried into the shallow layer soil, and the improved soil in the planting greenhouse is obtained. The porosity of the improved soil was increased by 10%, the water holding performance was increased by 10%, and the organic carbon content was increased by
    5.8%.
    According to a first group experiment, ryegrass was respectively planted in the impoverished soil and the improved soil. Through dry weight comparison of the ryegrass after 15-day growth, the growth speed of the ryegrass planted in the improved soil prepared by the present invention was improved by 25%.
    According to a second group experiment, vegetables (Chinese cabbages) were respectively planted in the impoverished soil and the improved soil. Through being compared with that of vegetables planted in the impoverished soil, the yield of the vegetables planted in the improved soil prepared by the present invention was improved by 30%.
    Embodiment 3 The present embodiment provides a method for remedying impoverished soil, including the following steps: Step 1, agricultural waste biomass including straw, wood chips, fallen leaves, crop waste and livestock manure was crushed, and a particle diameter of the crushed agricultural waste biomass was less than 0.12 mm.
    Step 2, the crushed agricultural waste biomass and water were subjected to hydrothermal carbonization, a mass ratio of the biomass to the water in the hydrothermal carbonization process was 1:4, a hydrothermal carbonization temperature was 290°C, a hydrothermal carbonization time was 350 min, a hydrothermal carbonization product was subjected to solid-liquid separation in a mechanical filtration or centrifugal separation manner to obtain solid-state hydrochar and hydrochar liquid, and the hydrochar liquid was recycled.
    Step 3, eutrophic hydrochar was prepared from part of the solid-state hydrochar according to a preparation method of the eutrophic hydrochar including the following steps: Step 1, the hydrochar was added into a calcium superphosphate solution with a concentration of 1480 mg/L to be uniformly stirred, hydrochar was separated out, and drying was performed under the condition of 45 to obtain dry hydrochar. Step ii, urea was added into a granulator, a polyvinyl alcohol water solution with a mass concentration of 9.4% was sprayed, and then, the dried hydrochar was added for granulation forming. The particle diameter of the urea was 0.1 mm, a mass ratio of the hydrochar to the urea was 1:9, and a particle diameter after the forming was 0.4 mm. Step iii, the bonding agent was continuously sprayed into the granulator, then, the dried hydrochar was added for granulation forming, and the step was repeated according to particle diameter requirements to finally obtain the eutrophic hydrochar with the particle diameter of 1.0 mm. Step 4, part of the solid-state hydrochar in step 2 and phosphoric acid were dissolved into water to obtain a mixture, the mixture is heated while stirring until moisture in the mixture was completely volatilized, microwave carbonization was performed at a microwave power of 800 W for a microwave carbonization time of 10 min in a microwave carbonization atmosphere of isolated air (sealed), nitrogen gas or argon gas, and after the microwave carbonization, the obtained biochar was washed and dried to obtain porous biochar. The drying temperature of the hydrochar was 100°C, and after drying, the moisture of the hydrochar was 3%. A heating temperature in the stirring process in a phosphoric acid solution was 75°C. A washing medium of the biochar was water, and a pH value of the washed biochar was 7.5, a drying temperature was 120°C, and a drying time was 590 min. Step 5, the hydrochar prepared in step 2, the eutrophic hydrochar prepared in step 3 and the porous biochar prepared in step 4 were mixed according to a mass proportion of 1:1:0.7 to obtain an impoverished soil improving agent.
    According to this embodiment, the soil improving agent was added into the greenhouse planting impoverished soil according to a mass ratio of 10%, the surface layer impoverished soil in a greenhouse was shallowly cultivated by using a ploughing machine, so that the soil improving agent spread onto the ground surface could be 5S buried into the shallow layer soil, and the improved soil in the planting greenhouse 1s obtained. The porosity of the improved soil was increased by 12%, the water holding performance was increased by 13%, and the organic carbon content was increased by
    6.9%. According to a first group experiment, ryegrass was respectively planted in the impoverished soil and the improved soil. Through dry weight comparison of the ryegrass after 15-day growth, the growth speed of the ryegrass planted in the improved soil prepared by the present invention was improved by 24%. According to a second group experiment, vegetables (Chinese cabbages) were respectively planted in the impoverished soil and the improved soil. Through being compared with that of vegetables planted in the impoverished soil, the yield of the vegetables planted in the improved soil prepared by the present invention was improved by 31%. The foregoing descriptions are merely exemplary specific implementations of the present invention, but are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention.
    权利要求:
    Claims (10)
    [1]
    -15 - Conclusions l. A method of restoring depleted soil, the method comprising the steps of: step 1, crushing agricultural waste biomass; step 2, performing hydrothermal carbonization on the crushed agricultural waste biomass and water, performing solid-liquid separation on a hydrothermal carbonization product to obtain solid-state hydrocoal and liquid hydrocoal, and reusing the liquid hydrocoal; step 3, preparing eutrophic hydrocoal from a portion of the solid state hydrocoal; step 4, dissolving part of the solid-state hydrocarbon in step 2 and an activating agent in water to obtain a mixture, heating the mixture with stirring until moisture in the mixture is completely evaporated, performing microwave carbonization, and after the microwave carbonization, washing and drying the generated hydrocarbon to obtain porous biocoal, wherein a microwave power during microwave carbonization is 500 - 800 W, a microwave carbonization time is 4 - 10 min, and a microwave carbonization atmosphere is isolated air, nitrogen gas or argon gas; and step 5, proportionally mixing the hydrocoal prepared in step 2, the eutrophic hydrocoal prepared in step 3, and the porous biocoal prepared in step 4 to obtain a depleted soil amelioration agent, and adding the Impoverished Earth improver in Depleted Earth for Earth restoring.
    [2]
    The method of restoring depleted soil according to claim 1, wherein in step 1, the agricultural waste biomass comprises straw, wood chips, fallen leaves, crop waste and livestock manure, and a particle diameter of the crushed agricultural waste biomass is less than 0.18 mm.
    [3]
    The method of restoring depleted soil according to claim 1, wherein in step 2, a mass ratio of the biomass to the water in the hydrothermal carbonization process is 1:1 - 1:4, a
    -16 - hydrothermal carbonization temperature is 180-300°C, a hydrothermal carbonization time is 60-360 min, and a way of solid-liquid separation is mechanical filtration or centrifugal separation.
    [4]
    The method of restoring depleted soil according to claim 1, wherein in step 4, a drying temperature of the hydrocoal is 60-100°C, and a moisture content of the dried hydrocoal is less than 5%.
    [5]
    The method of restoring depleted soil according to claim 1, wherein in step 4 the activating agent is one of sodium hydroxide, potassium hydroxide and phosphoric acid; and a heating temperature in a stirring process of an activator solution is less than 100°C.
    [6]
    A method of restoring depleted soil according to claim 1, wherein in step 4 a washing medium of the biocoal is water, and a pH value of the washed biocoal is 6.5 - 7.5, a drying temperature is 80 - 120°C and a drying time is 300 — 600 min.
    [7]
    The depleted soil restoring method according to claim 1, wherein in step 5 a mass ratio of the hydrocoal to the eutrophic hydrocoal to the porous biocoal is 1:0.5 1:0.4 0.8, and an addition amount in the impoverished earth is 3% — 10%.
    [8]
    The method of restoring depleted soil according to claims 1-7, wherein in step 3 a method of preparing the eutrophic hydrocoal comprises the following steps: step 1, adding the hydrocoal in a nutrient solution having a concentration of 500 - 1500 mg/L, performing sufficient stirring to separate hydrocoal, and drying the hydrocoal at a temperature less than 70°C to obtain the dried hydrocoal; step ii, adding urea in a granulator, fracturing a binder, and then adding the dried hydrocarbon for granulation formation; and
    “17 - step iii, continuously spraying the binder into the granulator, then adding the dried hydrocoal for granulation formation, and repeating the step according to the requirements to finally obtain the eutrophic hydrocoal having a particle diameter of 0.5-1, 0 mm available.
    [9]
    The depleted soil restoration method according to claim 8, wherein in step ii a particle diameter of the urea is 0.074 - 0.1 mm, and the binder is a polyvinyl alcohol water solution having a mass concentration of 3.0 - 10.0 %; and a mass ratio of the hydrocarbon to the urea is 1:4, and a particle diameter after the molding is 0.2 - 0.4 mm.
    [10]
    The method of restoring depleted soil according to claim 8, wherein in step i the nutrient solution is one or more of monopotassium phosphate, ammonium dihydrogen phosphate, magnesium phosphate and calcium superphosphate.
    类似技术:
    公开号 | 公开日 | 专利标题
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    同族专利:
    公开号 | 公开日
    CN112872009A|2021-06-01|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CN102424642A|2011-09-25|2012-04-25|西北农林科技大学|Method for producing biocarbon-based slow-release nitrogen fertilizer|
    CN106732352A|2016-11-16|2017-05-31|广州大学|A kind of multiporous biological charcoal and its synthetic method and application|
    CN107815315A|2017-10-20|2018-03-20|福建省农业科学院农业生态研究所|A kind of soil conditioner, its preparation method and application for improving saline-alkali soil|
    CN107916108A|2017-10-20|2018-04-17|福建省农业科学院农业生态研究所|A kind of soil conditioner, its preparation method and application|
    CN111408343B|2019-01-08|2022-01-28|湖南农业大学|Preparation method of three-dimensional biochar and application of three-dimensional biochar in heavy metal adsorption|
    CN111036174A|2019-12-13|2020-04-21|南京师范大学|Magnetic biochar based on iron-enriched plants and preparation method and application thereof|
    CN111014254B|2019-12-26|2020-11-27|郑州大学|Red mud ecological restoration method and restoration system by using biomass|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    CN202110354856.9A|CN112872009A|2021-03-31|2021-03-31|Method for restoring impoverished soil|
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