A preparation method and application of biochar composed of multi-source solid waste

Abstract

The present invention relates to a preparation method and application of biochar composed of multi-source solid waste, comprising the following steps: S1: crushing agricultural and forestry waste to obtain granular material; S2: treating the granular material by any one of physical, chemical and biological methods or any combination of two or more methods to obtain a first material; S3: using organic water-containing solid waste as a second material, and mixing the first material and the second material to obtain a mixed material; S4: deeply dehydrating the mixed material, and drying the dehydrated mixed material to obtain a third material; S5: crushing the third material to prepare biomass carbon materials of different particle sizes. The preparation method of the present invention can prepare biomass carbon materials using multi-source waste as raw materials, and can be applied to supercapacitors and adsorption of debris in water to achieve high-value utilization of waste, and belongs to the field of waste treatment technology.

Description

Technical Field

[0001] The present invention relates to the technical field of waste treatment, and in particular to a method for preparing biochar composed of multi-source solid waste and its application. Background Art

[0002] With the rapid development of urbanization and industrialization, the waste generated and the disposal rate are out of balance. Most of the water-containing waste disposal methods are single and non-cooperative disposal technology routes. The deep dehydration cost is high and the energy consumption is large, resulting in low resource utilization. At present, the discharge of multi-source organic solid waste (including but not limited to urban domestic sludge, industrial wastewater sludge, food processing waste, etc.) and agricultural and forestry waste (such as crop straw, forest prunings, fruit shells, etc.) has increased sharply, bringing great pressure to the ecological environment. Traditional treatment methods, such as landfill, incineration or simple composting, not only occupy a large amount of land resources, but also may cause soil, water and air pollution, which is not in line with the development concept of green circular economy. Summary of the invention

[0003] In view of the technical problems existing in the prior art, the purpose of the present invention is to provide a method for preparing and applying biochar composed of multi-source solid waste, which solves the problem of treating multi-source organic solid waste and agricultural and forestry waste. The preparation method can prepare biomass carbon materials using multi-source waste as raw materials, and can be applied to supercapacitors and adsorption of debris in water, thereby realizing high-value utilization of waste.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: A method for preparing biochar using multi-source solid waste comprises the following steps: S1: crushing agricultural and forestry waste to obtain pellets; S2: Processing the granular material by any one of physical, chemical and biological methods or a combination of any two or more methods to obtain a first material; S3: using organic water-containing solid waste as the second material, and mixing the first material and the second material to obtain a mixed material, utilizing the interaction between the active groups on the surface of the first material and the moisture of the second material to balance the hydrophilicity and hydrophobicity of the second material; S4: Deeply dehydrating the mixed material, and drying the dehydrated mixed material to obtain a third material; S5: crushing the third material to prepare biomass carbon materials with different particle sizes.

[0005] As a preferred embodiment, in step S1, the agricultural and forestry waste includes straw, peanut shells, bagasse, coconut shells, walnut shells, orange peels and grapefruit peels, and the method for crushing the agricultural and forestry waste to obtain granular materials is: one or more of the agricultural and forestry wastes are crushed by a mechanical crushing method, passed through a 10-500 mesh sieve, and prepared into a first material of 25-1000 microns.

[0006] As a preferred embodiment, in step S2, the first material is obtained by subjecting the granular material to physical, chemical and biological synergistic treatment, wherein the physical method includes any one of hydrothermal treatment, microwave and ultrasound, the hydrothermal treatment in the physical method has a hydrothermal time of 1 to 12 hours and a hydrothermal temperature of 80 to 180°C; the microwave power in the microwave method is 100-1000W and the time is 5-60min; the ultrasonic power in the ultrasonic method is 10W-500W and the time is 5-90min; the chemical method includes any one of alkali method, acid method and oxidation method, and the alkali method in the chemical method includes Na Any one of OH, KOH and Ca(OH)2, with a concentration of 0.1-6 mol / L; the acid method includes any one of sulfuric acid, hydrochloric acid, acetic acid, citric acid, nitric acid and phosphoric acid, with a concentration of 0.1-5 mol / L; the oxidation method includes any one of hydrogen peroxide, potassium permanganate, sodium hypochlorite, sodium periodate and ozone, with a concentration of 0.05-5 mol / L; the biological method includes any one of white rot fungi, brown rot fungi, soft rot fungi, cellulase, xylanase, lysozyme, laccase and pectinase, and the addition amount is 0.01%-10% of the dry weight of the first material.

[0007] As a preferred embodiment, in step S3, the organic aqueous solid waste includes kitchen waste, domestic waste, municipal sludge, Chinese medicine residues and tea residues.

[0008] As a preference, in step S3, the mixing ratio of the first material to the second material is 1:1-1:10.

[0009] Preferably, in step S4, the drying temperature for drying the dehydrated mixed material is 60-120°C.

[0010] As a preferred embodiment, in step S5, the method for crushing the third material to prepare biomass carbon materials of different particle sizes is: firstly crush the third material and then calcine it under an inert atmosphere, after the calcination is completed, soak and wash the third material until it is neutral, and then dry the third material to obtain biomass carbon materials of different particle sizes.

[0011] As a preference, the inert atmosphere is any one of nitrogen, helium, neon, argon and krypton atmospheres.

[0012] As a preferred embodiment, the calcination temperature is 300-1000°C, the calcination time is 0.5-6h, and the insulation time after calcination is 0.5-2h.

[0013] An application of biochar composed of multi-source solid waste, including biochar prepared by a biochar preparation method, wherein the biochar is applied to electrode preparation materials of supercapacitors; the biochar can also be used to adsorb organic matter and heavy metal ions in water.

[0014] In general, the present invention has the following advantages: The preparation method of the present invention can prepare biomass carbon materials with multi-source waste as raw materials, and can be applied to supercapacitors and adsorption of debris in water to achieve high-value utilization of waste; the method not only achieves the environmental protection goal of treating waste with waste through specific mixing ratios, particle size control, and coordinated treatment strategies, but also cleverly uses these wastes as raw materials, and prepares biomass carbon materials with hierarchical and adjustable pore structures by adjusting the treatment conditions. This biomass carbon material can not only meet the requirements of high-end fields such as supercapacitors and adsorption for material performance, but also achieves high-value utilization of waste through a low-cost and high-efficiency production process, and opens up a new way for the resource conversion of organic solid waste and agricultural and forestry waste. It solves the problem of multi-source organic solid waste and agricultural and forestry waste treatment, and also promotes the development of biomass carbon material preparation technology, providing new solutions for the fields of environmental protection and energy, and has important social, economic and environmental values. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a flow chart of a method for preparing biochar composed of multi-source solid waste. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below in conjunction with specific implementation methods.

[0017] Embodiment 1 like Figure 1 As shown, the present embodiment provides a method for preparing biochar using multi-source solid waste, comprising the following steps: S1: crushing agricultural and forestry waste to obtain granular material; S2: Processing the granular material by any one of physical, chemical and biological methods or a combination of any two or more methods to obtain a first material; S3: The organic water-containing solid waste is used as the second material, and the first material and the second material are mixed to obtain a mixed material. The first material has a rigid structure, and after being synergistically treated by two or more methods of physical, chemical, and biological methods, more active groups (carboxyl, hydroxyl, etc.) are exposed on its surface. These groups can optimize the physical and chemical properties of the second material, and the active groups on the surface of the first material interact with the moisture of the second material to balance the hydrophilicity and hydrophobicity of the second material and improve the dehydration effect. S4: Deeply dehydrating the mixed material, and drying the dehydrated mixed material to obtain a third material; the deep dehydration method may be an existing mechanical dehydration method; S5: crushing the third material to prepare biomass carbon materials with different particle sizes.

[0018] In step S1, the agricultural and forestry waste includes straw, peanut shells, bagasse, coconut shells, walnut shells, orange peels and grapefruit peels. The method for crushing the agricultural and forestry waste to obtain granular materials is: one or more of the agricultural and forestry wastes are crushed by a mechanical crushing method, passed through a 10-500 mesh sieve, and prepared into a first material of 25-1000 microns.

[0019] In step S2, the first material is obtained by subjecting the granular material to physical, chemical and biological coordinated treatment, wherein the physical method includes any one of hydrothermal treatment, microwave and ultrasound, the hydrothermal treatment in the physical method, the hydrothermal time is 1 to 12 hours, and the hydrothermal temperature is 80 to 180°C; the microwave power in the microwave method is 100-1000W, the time is 5-60min; the ultrasonic power in the ultrasonic method is 10W-500W, and the time is 5-90min; the chemical method includes any one of alkali method, acid method and oxidation method, and the alkali method in the chemical method includes Na Any one of OH, KOH and Ca(OH)2, with a concentration of 0.1-6 mol / L; the acid method includes any one of sulfuric acid, hydrochloric acid, acetic acid, citric acid, nitric acid and phosphoric acid, with a concentration of 0.1-5 mol / L; the oxidation method includes any one of hydrogen peroxide, potassium permanganate, sodium hypochlorite, sodium periodate and ozone, with a concentration of 0.05-5 mol / L; the biological method includes any one of white rot fungi, brown rot fungi, soft rot fungi, cellulase, xylanase, lysozyme, laccase and pectinase, and the addition amount is 0.01%-10% of the dry weight of the first material.

[0020] In step S3, the organic aqueous solid waste includes kitchen waste, domestic waste, municipal sludge, Chinese medicine residues and tea residues.

[0021] In step S3, the mixing ratio of the first material and the second material is 1:1-1:10.

[0022] In step S4, the dehydrated mixed material is dried at a drying temperature of 60-120°C.

[0023] In step S5, the method for crushing the third material to prepare biomass carbon materials with different particle sizes is: first crush the third material and then calcine it under an inert atmosphere, after calcination, soak and wash the third material until it is neutral, and then dry the third material to obtain biomass carbon materials with different particle sizes.

[0024] The inert atmosphere is any one of nitrogen, helium, neon, argon and krypton atmospheres.

[0025] The calcination temperature is 300-1000°C, the calcination time is 0.5-6h, and the insulation time after calcination is 0.5-2h.

[0026] Embodiment 2 This embodiment provides an application of biochar composed of multi-source solid waste, including biochar prepared by a biochar preparation method, and the biochar is applied to electrode preparation materials for supercapacitors; the biochar can also be used to adsorb organic matter and heavy metal ions in water.

[0027] The parts not mentioned in this embodiment are the same as those in the first embodiment.

[0028] Application Example 1 The ratio of the first material to the second material is 1:1; The first material is a mixture of 20% straw, 40% peanut shells and 40% walnut shells; after mechanical crushing, it is passed through a 200-mesh sieve to obtain a first material with a particle size of about 70um; After ultrasonic pretreatment at an ultrasonic power of 200w for 5min, the first material was immersed in a 1mol / L NaOH solution for 8h, chemically pretreated, dried at 65°C, and mixed with the second material after drying; The second material is a mixture of 50% sludge and 50% Chinese medicine residue, with a moisture content greater than 80%; The first material and the second material are uniformly mixed and then mechanically dehydrated to reduce the moisture content to 48.3%, and then dried to obtain the third material.

[0029] The third material is crushed to prepare biomass carbon material, wherein the third material is crushed and passed through a 200-mesh sieve to obtain a material with a particle size of about 70 um.

[0030] Biochar preparation process: nitrogen was introduced as the gas, first at 5 ℃·min -1 The rate was raised from room temperature to 600 ℃ for carbonization for 3 h and then kept warm for 1 h to obtain biochar, which was washed and dried for later use.

[0031] The specific surface area and pore size of the obtained biochar are shown in the following table:

[0032] The parts not mentioned in this embodiment are the same as those in the first embodiment.

[0033] Application Example 2 The ratio of the first material to the second material is 1:5; The first material is a mixture of 30% straw, 20% peanut shells, 40% bagasse, and 10% orange peels; After mechanical crushing, the particles were passed through a 100-mesh sieve to obtain a first material with a particle size of about 150 um. Then, the first material is subjected to hydrothermal pretreatment for 3 hours at a hydrothermal temperature of 80°C, and is soaked in a 1 mol / L KOH solution for 6 hours. After chemical pretreatment, the first material is dried at 65°C and mixed with the second material after drying. The second material is a mixture of 60% sludge, 20% Chinese medicine residue, and 20% kitchen waste, with a moisture content greater than 80%; The first material and the second material are uniformly mixed and then mechanically dehydrated to reduce the moisture content to 54.2%, and then dried to obtain the third material.

[0034] The third material is crushed to prepare biochar material, wherein the third material is crushed and passed through a 200-mesh sieve to obtain a material with a particle size of about 70 um.

[0035] Biochar preparation process: nitrogen was introduced as the gas, first at 5 ℃·min -1 The temperature was carbonized at a rate of 600 °C from room temperature for 3 h and then kept at that temperature for 1 h to obtain biochar, which was washed and dried for later use.

[0036] The specific surface area and pore size of the obtained biochar are shown in the following table:

[0037] The parts not mentioned in this embodiment are the same as those in the first embodiment.

[0038] Application Example 3 The ratio of the first material to the second material is 1:8; The first material is a mixture of 20% straw, 20% walnut shell, 30% bagasse and 30% grapefruit peel; After mechanical crushing, the particles are passed through a 150-mesh sieve to obtain a first material with a particle size of about 100 um; Then, the first material is subjected to hydrothermal pretreatment for 1 hour at a hydrothermal temperature of 100° C., and is soaked in a 0.5 mol / L acetic acid solution for 3 hours. After chemical pretreatment, the first material is dried at 65° C. and mixed with the second material after drying. The second material is 100% sludge, with a moisture content greater than 80%; The first material and the second material are uniformly mixed and then mechanically dehydrated to reduce the moisture content to 59.7%, and then dried to obtain the third material.

[0039] The third material is crushed to prepare a biochar material, wherein the third material is crushed and passed through a 100-mesh sieve to obtain a material with a particle size of about 150 um; Biochar preparation process: nitrogen was introduced as the gas, first at 5 ℃·min -1 The temperature was carbonized at a rate from room temperature to 600 °C for 3 h and then kept warm for 1 h to obtain biochar, which was washed and dried for later use.

[0040] The specific surface area and pore size of the obtained biochar are shown in the following table:

[0041] The parts not mentioned in this embodiment are the same as those in the first embodiment.

[0042] in conclusion: After deep dehydration in application example 1, a lower moisture content is obtained, and the prepared biochar has a larger specific surface area, and the average pore size is less than 2nm, which is microporous; after deep dehydration in application example 2, the moisture content of the material obtained is higher than that in application example 1, and the specific surface area of ​​the prepared biochar is reduced, and the average pore size is greater than 2nm, which is mesoporous; after deep dehydration in application example 3, the moisture content of the material obtained is higher than that in application example 2, and the specific surface area of ​​the prepared biochar is sharply reduced, and the average pore size is increased, but it is still mesoporous. Therefore, by regulating the particle size of the first material, the coordinated processing method, the ratio of the first material to the second material, and the particle size of the third material, the specific surface area and pore size distribution of the biomass carbon material can be adjusted to achieve the preparation of graded biomass carbon materials with adjustable pore size.

[0043] Application advantages: In supercapacitors, biochar with a high specific surface area has more charge storage sites and can be used as an electrode material to increase the charge storage capacity of the capacitor; in the field of adsorption, biochar with a high specific surface area can effectively adsorb pollutants such as organic matter and heavy metal ions in water to improve purification efficiency. Therefore, the preparation method of Example 1 is used to obtain biochar with different particle sizes according to different material ratios and crushing. When applied to the preparation of supercapacitor electrode materials and the adsorption field, it not only has a good effect, but also solves the problem of waste disposal.

[0044] In addition, according to the size of the pores, porous carbon materials can be divided into three categories: microporous carbon materials (pore size <2 nm), mesoporous carbon materials (2 < pore size <50 nm) and macroporous carbon materials (pore size >50 nm). The adsorption of electrolyte ions mainly occurs on the surface of micropores. Properly increasing the number of micropores can improve the electrochemistry of supercapacitors. Mesopores can provide channels for ion transport, and the role of macropores is to store electrolytes and form ion buffers. Reasonable pore size distribution can effectively improve the electrochemical performance of supercapacitors. Therefore, regulating the specific surface area and pore size structure of biochar according to practical applications is of great significance in the fields of supercapacitors and adsorption.

[0045] Based on this, the present invention adopts deep dehydration after mixing agricultural and forestry waste with multi-source organic solid waste to achieve waste treatment with waste, and uses the two as raw materials. By changing the particle size of the first material, the coordinated processing method, the ratio of the first material to the second material, and the particle size of the third material, the pore structure of the biomass carbon material can be adjusted to achieve the preparation of graded biomass carbon materials with adjustable pore structure, which can meet the application of supercapacitors, adsorption and other fields, and obtain low-cost and high-value-added products.

[0046] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing biochar using multi-source solid waste, characterized in that: The following steps are involved: S1: crushing agricultural and forestry waste to obtain pellets; S2: Processing the granular material by any one of physical, chemical and biological methods or a combination of any two or more methods to obtain a first material; S3: using organic water-containing solid waste as the second material, and mixing the first material and the second material to obtain a mixed material, utilizing the interaction between the active groups on the surface of the first material and the moisture of the second material to balance the hydrophilicity and hydrophobicity of the second material; S4: Deeply dehydrating the mixed material, and drying the dehydrated mixed material to obtain a third material; S5: crushing the third material to prepare biomass carbon materials with different particle sizes.

2. A method for preparing biochar using multi-source solid waste according to claim 1, characterized in that: In step S1, the agricultural and forestry waste includes straw, peanut shells, bagasse, coconut shells, walnut shells, orange peels and grapefruit peels. The method for crushing the agricultural and forestry waste to obtain granular materials is: one or more of the agricultural and forestry wastes are crushed by a mechanical crushing method, passed through a 10-500 mesh sieve, and prepared into a first material of 25-1000 microns.

3. The method for preparing biochar using multi-source solid waste according to claim 1, characterized in that: In step S2, the first material is obtained by subjecting the granular material to physical, chemical and biological coordinated treatment, wherein the physical method includes any one of hydrothermal treatment, microwave and ultrasound, the hydrothermal treatment in the physical method, the hydrothermal time is 1 to 12 hours, and the hydrothermal temperature is 80 to 180°C; the microwave power in the microwave method is 100-1000W, the time is 5-60min; the ultrasonic power in the ultrasonic method is 10W-500W, and the time is 5-90min; the chemical method includes any one of alkali method, acid method and oxidation method, and the alkali method in the chemical method includes Na Any one of OH, KOH and Ca(OH)2, with a concentration of 0.1-6 mol / L; the acid method includes any one of sulfuric acid, hydrochloric acid, acetic acid, citric acid, nitric acid and phosphoric acid, with a concentration of 0.1-5 mol / L; the oxidation method includes any one of hydrogen peroxide, potassium permanganate, sodium hypochlorite, sodium periodate and ozone, with a concentration of 0.05-5 mol / L; the biological method includes any one of white rot fungi, brown rot fungi, soft rot fungi, cellulase, xylanase, lysozyme, laccase and pectinase, and the addition amount is 0.01%-10% of the dry weight of the first material.

4. The method for preparing biochar using multi-source solid waste according to claim 1, characterized in that: In step S3, the organic aqueous solid waste includes kitchen waste, domestic waste, municipal sludge, Chinese medicine residues and tea residues.

5. The method for preparing biochar using multi-source solid waste according to claim 1, characterized in that: In step S3, the mixing ratio of the first material and the second material is 1:1-1:

10.

6. The method for preparing biochar using multi-source solid waste according to claim 1, characterized in that: In step S4, the dehydrated mixed material is dried at a drying temperature of 60-120°C.

7. The method for preparing biochar using multi-source solid waste according to claim 1, characterized in that: In step S5, the method for crushing the third material to prepare biomass carbon materials with different particle sizes is: first crush the third material and then calcine it under an inert atmosphere, after calcination, soak and wash the third material until it is neutral, and then dry the third material to obtain biomass carbon materials with different particle sizes.

8. A method for preparing biochar using multi-source solid waste according to claim 7, characterized in that: The inert atmosphere is any one of nitrogen, helium, neon, argon and krypton atmospheres.

9. The method for preparing biochar using multi-source solid waste according to claim 7, characterized in that: The calcination temperature is 300-1000°C, the calcination time is 0.5-6h, and the insulation time after calcination is 0.5-2h.

10. An application of biochar composed of multi-source solid waste, characterized by: The biochar is prepared by the method for preparing biochar according to any one of claims 1 to 9, and the biochar is applied to the electrode preparation material of supercapacitors; the biochar can also be used to adsorb organic matter and heavy metal ions in water.

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