CN111704134A - Wave-absorbing material based on agricultural and forestry waste recycling and preparation method thereof - Google Patents
Wave-absorbing material based on agricultural and forestry waste recycling and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a wave-absorbing material, in particular to a wave-absorbing material based on agricultural and forestry waste recycling and a preparation method thereof. The material takes agricultural and forestry waste (including walnut shells, shinyleaf yellowhorn shells and the like) as raw materials, and can obtain a finished product of the porous carbon wave-absorbing material by four steps of crushing and screening the raw materials, preparing in the early stage of washing, carrying out ultrasonic activation pretreatment, carrying out staged heating carbonization treatment and carrying out freeze drying treatment, and the purpose of microwave absorption is realized by utilizing the structural characteristics of the material. The product has good wave absorbing performance, takes agricultural and forestry wastes as raw materials, increases the value of the traditional agricultural and forestry wastes, reduces the waste of biomass and avoids environmental pollution. The invention has the advantages of low material cost, no pollution in preparation and high product performance, conforms to the concept of sustainable development, provides a scheme for resource utilization of agricultural and forestry wastes, enriches the types of wave-absorbing materials and provides technical support for popularization of the wave-absorbing materials.
Description
Technical Field
The invention relates to a wave-absorbing material, in particular to a wave-absorbing material based on agricultural and forestry waste recycling and a preparation method thereof.
Background
The rapid development of electronic equipment brings convenience to the life of people, and microwaves play an increasingly important role in various fields such as the life of people, military, aerospace and the like. However, with the large use of electronic equipment, excessive microwaves have become the fifth world pollution following water pollution, air pollution, noise pollution and solid waste pollution. Excessive microwaves not only can influence the operation of precision instruments and interfere communication to cause air accidents, but also can seriously harm the health of people, and greatly improve the possibility that the people suffer from absolute symptoms such as leukemia, cancer and the like. Therefore, the protection against microwaves has become a research hotspot for researchers. Microwave protection mainly includes two ways of absorption and shielding, among which microwave absorbing Materials (MAs) having thinner thickness, lighter weight, wider absorption band and stronger absorption performance have attracted great research interest because of their unique characteristics of effectively absorbing the emitted electromagnetic waves and achieving the purpose of microwave attenuation by converting electromagnetic energy into other forms of energy such as electric energy and thermal energy or by means of interference cancellation, and their superior performance.
The Biomass Porous Carbon (BPC) material is a porous solid particle material rich in carbon prepared by carrying out high-temperature pyrolysis on biomass raw materials under specific conditions. The biomass porous carbon material has a certain microporous structure due to the fact that the raw material has a certain microporous structure and a large amount of medium and large pore structures are generated by activation of an activating agent in preparation, so that the material has an extremely rich multi-stage pore channel structure. In the microwave absorption aspect, the biomass porous carbon material mainly utilizes the unique structure of the material itself to generate a large amount of interface polarization by forming a large amount of solid-air interfaces, thereby causing the attenuation of microwaves. In addition, the large number of pore structures cause the microwave to be reflected and scattered on the surface of the pore after entering the interior of the material for several times, and further aggravate the attenuation of the microwave.
As the largest walnut planting country in the world, China has considerable annual output of walnuts, but a great amount of agricultural and forestry waste walnut shells which are difficult to treat are generated. Walnut shells are rich in lignin, cellulose and other substances, are extremely stable in properties, and are difficult to degrade. Traditional treatment mainly depends on landfill and incineration, which both have great harm to the environment and also cause great waste of biomass. Therefore, the walnut shells are used as a biomass carbon source, so that not only can a great deal of waste of biomass be avoided, but also the environmental pollution caused by the treatment of the walnut shells can be greatly reduced. The invention provides a new material for the research of wave-absorbing materials and a new idea for the resource utilization of the agricultural and forestry waste walnut shells. At present, the document and patent report that the walnut shell is used as a biomass carbon source to prepare the biomass porous carbon and the biomass porous carbon is applied to the field of wave-absorbing materials are rarely seen.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, provides the porous carbon wave-absorbing material prepared based on the biomass material and the preparation method thereof, which have the advantages of low preparation cost, simple preparation process, small preparation pollution, good wave-absorbing performance and wide wave-absorbing frequency band, and provides a new idea for resource utilization of traditional agricultural and forestry wastes which are difficult to treat.
The basic idea of the invention is as follows: agricultural and forestry wastes (including walnut shells, shinyleaf yellowhorn shells and the like) are used as a biomass carbon source, and a chemical activation method is adopted to prepare the porous carbon material through the processes of ultrasonic activation pretreatment, carbonization treatment and drying treatment. The biomass-based porous carbon material prepared by the method is in an indefinite form, has rich multi-level pore channel structures in the surface area, is low in material density and high in dielectric loss capacity, can well convert microwaves into electric energy and heat energy so as to achieve the purpose of microwave attenuation, plays a positive role in the development of wave-absorbing materials, and provides a new application approach and field for the resource utilization of walnut shells.
The technical scheme for realizing the purpose of the invention is as follows:
the utility model provides a microwave absorbing material based on agriculture and forestry discarded object is recycled, agriculture and forestry discarded object is nut shell biomass material, microwave absorbing material is the porous carbon wave absorbing material who adopts the nut shell preparation, porous carbon wave absorbing material can utilize its material self structural feature to realize the microwave absorption.
According to the technical scheme, the agricultural and forestry waste is walnut shells or shinyleaf yellowhorn shells.
According to the technical scheme, the porous carbon material prepared from the biomass material is an amorphous carbon material, and the pore size distribution of the amorphous carbon material is 0.05-1 mu m.
A preparation method of a wave-absorbing material based on agricultural and forestry waste recycling is characterized by comprising the following steps: the method comprises the following steps:
(1) preparation of raw materials: cleaning walnut shell or xanthoceras sorbifolia Bunge shell, pulverizing, sieving, washing with water and ethanol, and drying;
(2) ultrasonic activation pretreatment: adding the dry shell powder and an activating agent into water, performing ultrasonic pretreatment, performing suction filtration and drying;
(3) step heating carbonization treatment: taking a proper amount of the pretreated material, putting the material into a tubular furnace, and carrying out carbonization reaction treatment in an inert gas atmosphere, wherein the carbonization process adopts stage programmed heating;
(4) and (3) freeze drying treatment: grinding the fluffy black solid obtained after the reaction by using an agate mortar, sequentially and repeatedly cleaning the fluffy black solid for a plurality of times by using different detergents, and freeze-drying the fluffy black solid by using a freeze-dryer to obtain a black powdery porous carbon wave-absorbing material prepared based on the biomass material.
According to the technical scheme, in the step (1), the sieve of the crushed walnut shells is 60 meshes.
In the above technical scheme, in the step (2), the activating agent is alkali metal salts of alcohol including potassium hydroxide, sodium hydroxide, alkaline potassium salt, sodium salt and including potassium ethoxide and sodium ethoxide; the mass ratio of the treated walnut shell powder to the carbon agent of the activating agent is 1: (1-3), wherein the solid-liquid mass ratio of the shell powder to the deionized water is 1: (10-15), the ultrasonic activation pretreatment time is 60min, and the drying temperature of the activated powder is 60 ℃.
In the above technical scheme, in the step (3), the stage heating carbonization treatment is divided into three stages:
a. a water removal and impurity removal stage, wherein the heating rate is 3 ℃/min, and the heating interval is room temperature to (200-250 ℃);
b. in the internal carbonization stage of the material, the temperature rise rate is 5 ℃/min, the temperature rise interval is (200-250 ℃) to (500-600 ℃), and the heat preservation time is (0.5-1) h;
c. in the secondary pore-forming stage, the temperature rise rate is 4 ℃/min, the temperature rise interval is (500-600) DEG C to (650-900) DEG C, and the carbonization pore-forming time is (1-3) h; and after the carbonization reaction is finished, the cooling rate is (2-5) DEG C/min.
According to the technical scheme, in the step (4), the used washing agents are sequentially ionized water, hydrochloric acid and absolute ethyl alcohol, and are respectively washed for 2-3 times; the freeze drying time is (8-12) h.
In the technical scheme, the inert gas used in the step (3) is argon.
According to the technical scheme, in the step (4), the concentration of the hydrochloric acid is (0.5-1) mol/L, and the dosage of the three lotions is (50-100) ml each time.
After the technical scheme is adopted, the invention has the following positive effects:
(1) the invention utilizes agricultural and forestry wastes (including walnut shells, shinyleaf yellowhorn shells and the like) as biomass carbon sources to prepare the walnut shell-based porous carbon material, the prepared material has better dielectric loss capacity, and simultaneously, a large amount of air-solid interface polarization effect is generated on the surface and inside of the material, so that the microwave absorption capacity of the material is greatly improved. The invention provides a new idea for the development of the walnut industry and the shinyleaf yellowhorn industry and the resource utilization of waste walnut shells and shinyleaf yellowhorn shells, has important significance for the development of the industries, enriches the types of wave-absorbing materials and provides technical support for the popularization of the wave-absorbing materials.
(2) The biomass-based porous carbon material prepared by the invention is mostly applied to the fields of super capacitors, electrode materials, adsorbing materials and the like in the current research, and is rarely and independently applied to the wave-absorbing field. The invention provides a new material and a preparation method for the field of wave-absorbing materials, enriches the types of wave-absorbing materials, and provides more research directions and ideas for the research of the field.
(3) Activators useful in the present invention include potassium hydroxide, sodium hydroxide, basic potassium, sodium salts, and alkali metal salts of alcohols including potassium ethoxide and sodium ethoxide. The addition of the activating agent can remove impurities such as pigments and the like in the material which are difficult to remove, can further improve the pore-forming effect of the material in the subsequent pore-forming reaction, greatly increase the pore size distribution and the pore density of the material, improve the specific surface area of the material and enhance the wave-absorbing performance of the material; in addition, the raw materials are directly mixed with the activating agent in the preparation process, the preparation process is simpler, and the manufacturing cost is low.
(4) The preparation method is simple and convenient, the ideal porous carbon material can be obtained without carrying out multiple pore-forming on the material, the preparation method is low in cost, expensive catalysts or other expensive medicines are not required to be used, the medicine used in the preparation process is safe and non-toxic, no solid waste is generated, the preparation is pollution-free, the product is single, the purity is high, the yield is ideal, and the possibility of realizing industrial production is realized; meanwhile, a new way is provided for the research of the biomass carbon material in the field of wave-absorbing materials.
(5) In the preparation method, two steps of ultrasonic cleaning and magnetic mechanical stirring and activating of the activating agent in the traditional method are combined into ultrasonic activation pretreatment, so that the energy consumption is reduced, the corresponding time is saved, and meanwhile, the dispersion uniformity of the activating agent can be improved by utilizing the ultrasonic treatment, and the subsequent pore-forming effect is improved.
(6) In the preparation method, in the carbonization and calcination stage, the traditional one-time temperature programming is changed into the stage temperature raising and carbonization treatment, the three-stage temperature raising treatment is adopted for the first time, the carbonization effect is more ideal compared with the traditional direct temperature raising, the pore-forming effect of each stage can be greatly improved on the premise of keeping the original pore-forming effect, and the pore size distribution is more concentrated and uniform.
(7) According to the preparation method, the traditional hot blast drying is replaced by freeze drying, so that on the basis of ensuring the drying effect, the problem that the wave absorbing performance of the material is reduced due to collapse of the pore structure in the material caused by the gravity action of the water on the surface of the material in the hot blast drying can be solved, and the morphology and the wave absorbing performance of the material can be maintained to the greatest extent.
Drawings
In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the present disclosure taken in conjunction with the accompanying drawings, in which
FIG. 1 is a reflection loss curve of the wave-absorbing material based on agricultural and forestry waste recycling in example 1;
FIG. 2 is a micro-morphology of the wave-absorbing material based on agricultural and forestry waste recycling in example 1;
FIG. 3 is a reflection loss curve of the wave-absorbing material based on agricultural and forestry waste recycling in example 2;
FIG. 4 shows the micro-morphology of the wave-absorbing material based on the recycling of the agricultural and forestry waste in example 2.
Detailed Description
The wave-absorbing material based on agricultural and forestry waste recycling is prepared by taking walnut shells, which are traditional agricultural and forestry waste, as a biomass carbon source and adopting a chemical activation method through the processes of ultrasonic activation pretreatment, carbonization treatment and drying treatment in one step. The biomass-based porous carbon material prepared by the method is in an indefinite form, and the interior of the surface area of the material is provided with rich multi-stage pore channel structures.
The preparation method of the wave-absorbing material based on agricultural and forestry waste recycling comprises the following steps:
(1) preparation of raw materials: cleaning and crushing the purchased walnut shells or shinyleaf yellowhorn shells, sieving the crushed walnut shells or shinyleaf yellowhorn shells by a 60-mesh sieve, washing the crushed walnut shells or shinyleaf yellowhorn shells by water and ethanol in sequence, and drying the crushed walnut shells or shinyleaf yellowhorn shells for later use;
(2) ultrasonic activation pretreatment: taking 5g of the dried shell powder obtained in the previous step, and mixing the dried shell powder with an activating agent (comprising potassium hydroxide, sodium hydroxide, alkaline potassium salt, sodium salt and alkali metal salts of alcohol including potassium ethoxide and sodium ethoxide) according to a carbon-to-solvent mass ratio of 1: (1-3) mixing, adding into (50-75 ml) deionized water, carrying out ultrasonic pretreatment for 60min, carrying out suction filtration, and drying at 60 ℃;
(3) step heating carbonization treatment: and (3) taking a proper amount of the pretreated material, putting the material into a tubular furnace, and carrying out carbonization reaction treatment in an argon atmosphere, wherein the carbonization process adopts stage temperature programming. The stage heating carbonization treatment is divided into three stages: a. a water removal and impurity removal stage, wherein the heating rate is 3 ℃/min, and the heating interval is room temperature to (200-250 ℃); b. in the internal carbonization stage of the material, the temperature rise rate is 5 ℃/min, the temperature rise interval is (200-250 ℃) to (500-600 ℃), and the heat preservation time is (0.5-1) h; c. in the secondary pore-forming stage, the temperature rise rate is 4 ℃/min, the temperature rise interval is (500-600) DEG C to (650-900) DEG C, and the carbonization pore-forming time is (1-3) h. After the carbonization reaction is finished, cooling at the rate of (2-5) DEG C/min;
(4) and (3) freeze drying treatment: grinding the fluffy black solid obtained after the reaction by using an agate mortar, and then repeatedly washing the fluffy black solid for 8-12 times by using deionized water, (0.5-1) mol/L hydrochloric acid and absolute ethyl alcohol sequentially, wherein the dosage of the three kinds of washing agents is 50-100 ml each time. And then, carrying out freeze drying (8-12) h by using a freeze dryer to obtain a black powdery porous carbon wave-absorbing material prepared based on the biomass material.
Example 1
The wave-absorbing material based on agricultural and forestry waste recycling and the preparation method thereof comprise the following steps:
(1) preparation of raw materials: cleaning and crushing the purchased walnut shells, sieving the crushed walnut shells with a 60-mesh sieve, washing the crushed walnut shells with water and ethanol in sequence, and drying the crushed walnut shells for later use;
(2) ultrasonic activation pretreatment: taking 5g of the dry shell powder obtained in the previous step, and mixing the dry shell powder with an activating agent potassium hydroxide according to a carbon agent mass ratio of 1: 1.5 mixing, adding into 75ml deionized water, carrying out ultrasonic pretreatment for 60min, carrying out suction filtration, and drying at 60 ℃;
(3) step heating carbonization treatment: and (3) taking a proper amount of the pretreated material, putting the material into a tubular furnace, and carrying out carbonization reaction treatment in an argon atmosphere, wherein the carbonization process adopts stage temperature programming. The stage heating carbonization treatment is divided into three stages: a. in the stage of removing water and impurities, the temperature rising rate is 3 ℃/min, and the temperature rising interval is room temperature to 200 ℃; b. in the internal carbonization stage of the material, the temperature rise rate is 5 ℃/min, the temperature rise interval is 200-600 ℃, and the heat preservation time is 0.5 h; c. in the secondary pore-forming stage, the temperature rise rate is 4 ℃/min, the temperature rise interval is 600-700 ℃, and the carbonization pore-forming time is 2 h. The cooling rate is 4 ℃/min after the carbonization reaction is finished.
(4) And (3) freeze drying treatment: grinding the fluffy black solid obtained after the reaction by using an agate mortar, and then respectively cleaning the sample for 3 times by using deionized water, hydrochloric acid and absolute ethyl alcohol as detergents, wherein the dosage of each of the three detergents is 50 ml. And then, carrying out freeze drying for 8h by using a freeze dryer to obtain a black powdery porous carbon wave-absorbing material prepared based on the biomass material. The prepared porous carbon wave-absorbing material is mixed with a certain proportion of paraffin and poured into a hollow cylinder for wave-absorbing performance test. The minimum absorption value is-35.69 dB (17.2 GHz under 4.9 mm) when the content of the porous carbon wave-absorbing material is 20 wt%.
Example 2
The wave-absorbing material based on agricultural and forestry waste recycling and the preparation method thereof comprise the following steps:
(1) preparation of raw materials: cleaning and crushing the purchased walnut shells, sieving the crushed walnut shells with a 60-mesh sieve, washing the crushed walnut shells with water and ethanol in sequence, and drying the crushed walnut shells for later use;
(2) ultrasonic activation pretreatment: taking 5g of the dry shell powder obtained in the previous step, and mixing the dry shell powder with an activating agent potassium hydroxide according to a carbon agent mass ratio of 1: 1.5 mixing, adding into 75ml deionized water, carrying out ultrasonic pretreatment for 60min, carrying out suction filtration, and drying at 60 ℃;
(3) step heating carbonization treatment: and (3) taking a proper amount of the pretreated material, putting the material into a tubular furnace, and carrying out carbonization reaction treatment in an argon atmosphere, wherein the carbonization process adopts stage temperature programming. The stage heating carbonization treatment is divided into three stages: a. in the stage of removing water and impurities, the temperature rising rate is 3 ℃/min, and the temperature rising interval is room temperature to 200 ℃; b. in the internal carbonization stage of the material, the temperature rise rate is 5 ℃/min, the temperature rise interval is 200-600 ℃, and the heat preservation time is 0.5 h; c. in the secondary pore-forming stage, the temperature rise rate is 4 ℃/min, the temperature rise interval is 600-750 ℃, and the carbonization pore-forming time is 2 h. The cooling rate is 4 ℃/min after the carbonization reaction is finished.
(4) And (3) freeze drying treatment: grinding the fluffy black solid obtained after the reaction by using an agate mortar, and then respectively cleaning the sample for 3 times by using deionized water, hydrochloric acid and absolute ethyl alcohol as detergents, wherein the dosage of each of the three detergents is 50 ml. And then, carrying out freeze drying for 8h by using a freeze dryer to obtain a black powdery porous carbon wave-absorbing material prepared based on the biomass material. The prepared porous carbon wave-absorbing material is mixed with a certain proportion of paraffin and poured into a hollow cylinder for wave-absorbing performance test. The minimum absorption value is-54.88 dB (8.8 GHz under 2.7 mm) when the content of the porous carbon wave-absorbing material is 20 wt%.
Example 3
The wave-absorbing material based on agricultural and forestry waste recycling and the preparation method thereof comprise the following steps:
(1) preparation of raw materials: cleaning and crushing the obtained xanthoceras sorbifolia bunge shells, sieving the crushed xanthoceras sorbifolia bunge shells by a 60-mesh sieve, washing the crushed xanthoceras sorbifolia bunge shells by water and ethanol in sequence, and drying the washed xanthoceras sorbifolia bunge shells for later use;
(2) ultrasonic activation pretreatment: taking 5g of the dry shell powder obtained in the previous step, and mixing the dry shell powder with an activating agent potassium hydroxide and sodium hydroxide according to a carbon agent mass ratio of 1: 1.5 mixing, adding into 75ml deionized water, carrying out ultrasonic pretreatment for 60min, carrying out suction filtration, and drying at 60 ℃;
(3) step heating carbonization treatment: and (3) taking a proper amount of the pretreated material, putting the material into a tubular furnace, and carrying out carbonization reaction treatment in an argon atmosphere, wherein the carbonization process adopts stage temperature programming. The stage heating carbonization treatment is divided into three stages: a. in the stage of removing water and impurities, the temperature rising rate is 3 ℃/min, and the temperature rising interval is room temperature to 200 ℃; b. in the internal carbonization stage of the material, the temperature rise rate is 5 ℃/min, the temperature rise interval is 200-600 ℃, and the heat preservation time is 0.5 h; c. in the secondary pore-forming stage, the temperature rise rate is 4 ℃/min, the temperature rise interval is 600-800 ℃, and the carbonization pore-forming time is 2 h. The cooling rate is 4 ℃/min after the carbonization reaction is finished.
(4) And (3) freeze drying treatment: grinding the fluffy black solid obtained after the reaction by using an agate mortar, and then respectively cleaning the sample for 3 times by using deionized water, hydrochloric acid and absolute ethyl alcohol as detergents, wherein the dosage of each of the three detergents is 50 ml. And then, carrying out freeze drying for 8h by using a freeze dryer to obtain a black powdery porous carbon wave-absorbing material prepared based on the biomass material. The prepared porous carbon wave-absorbing material is mixed with a certain proportion of paraffin and poured into a hollow cylinder for wave-absorbing performance test. The minimum absorption value is-10.95 dB (18 GHz position under 1.2 mm) when the content of the porous carbon wave-absorbing material is 20 wt%.
Example 4
The wave-absorbing material based on agricultural and forestry waste recycling and the preparation method thereof comprise the following steps:
(1) preparation of raw materials: cleaning and crushing the obtained xanthoceras sorbifolia bunge shells, sieving the crushed xanthoceras sorbifolia bunge shells by a 60-mesh sieve, washing the crushed xanthoceras sorbifolia bunge shells by water and ethanol in sequence, and drying the washed xanthoceras sorbifolia bunge shells for later use;
(2) ultrasonic activation pretreatment: taking 5g of the dry shell powder obtained in the previous step, and mixing the dry shell powder with an activating agent sodium hydroxide according to a carbon agent mass ratio of 1: 1.5 mixing, adding into 75ml deionized water, carrying out ultrasonic pretreatment for 60min, carrying out suction filtration, and drying at 60 ℃;
(3) step heating carbonization treatment: and (3) taking a proper amount of the pretreated material, putting the material into a tubular furnace, and carrying out carbonization reaction treatment in an argon atmosphere, wherein the carbonization process adopts stage temperature programming. The stage heating carbonization treatment is divided into three stages: a. in the stage of removing water and impurities, the temperature rising rate is 3 ℃/min, and the temperature rising interval is room temperature to 200 ℃; b. in the internal carbonization stage of the material, the temperature rise rate is 5 ℃/min, the temperature rise interval is 200-600 ℃, and the heat preservation time is 0.5 h; c. in the secondary pore-forming stage, the temperature rise rate is 4 ℃/min, the temperature rise interval is 600-850 ℃, and the carbonization pore-forming time is 2 h. The cooling rate is 4 ℃/min after the carbonization reaction is finished.
(4) And (3) freeze drying treatment: grinding the fluffy black solid obtained after the reaction by using an agate mortar, and then respectively cleaning the sample for 3 times by using deionized water, hydrochloric acid and absolute ethyl alcohol as detergents, wherein the dosage of each of the three detergents is 50 ml. And then, carrying out freeze drying for 8h by using a freeze dryer to obtain a black powdery porous carbon wave-absorbing material prepared based on the biomass material. The prepared porous carbon wave-absorbing material is mixed with a certain proportion of paraffin and poured into a hollow cylinder for wave-absorbing performance test. The minimum absorption value is-8.99 dB (18 GHz position under 1.2 mm) when the content of the porous carbon wave-absorbing material is 20 wt%.
FIG. 1 is a reflection loss curve of the material of example 1, wherein the minimum reflection loss of the material shows a tendency of increasing first and then decreasing as the thickness of the wave-absorbing layer increases, based on the reflection loss curve of the wave-absorbing material recycled from agricultural and forestry waste within the range of 1-5.5mm and the frequency of 2-18 GHz; at 4.9mm, there is a minimum reflection loss of-35.69 dB (17.2 GHz);
FIG. 3 is a reflection loss curve of the material of example 2, wherein the minimum reflection loss of the material shows a tendency of increasing first and then decreasing as the thickness of the wave-absorbing layer increases, based on the reflection loss curve of the wave-absorbing material recycled from agricultural and forestry waste within the range of 1-5.5mm and the frequency of 2-18 GHz; at 2.7mm, there is a minimum reflection loss of-54.88 dB (8.8 GHz); meanwhile, the composite material can meet the requirements of wave-absorbing materials under different thicknesses (RL is less than or equal to-10 dB), and the frequency bands which can meet the wave-absorbing requirements under all thicknesses are all over 1.5GHz, so that the composite material is proved to be very suitable to be used as the wave-absorbing material.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A wave-absorbing material based on agricultural and forestry waste recycling is characterized in that: the agricultural and forestry waste is a nut shell biomass material, the wave-absorbing material is a porous carbon wave-absorbing material prepared from nut shells, and the porous carbon wave-absorbing material can realize microwave absorption by utilizing the structural characteristics of the material.
2. The wave-absorbing material based on agricultural and forestry waste recycling of claim 1, wherein: the agricultural and forestry waste is walnut shells or shinyleaf yellowhorn shells.
3. The wave-absorbing material based on agricultural and forestry waste recycling of claim 1 or 2, wherein: the porous carbon material prepared from the biomass material is an amorphous carbon material, and the pore size distribution of the amorphous carbon material is 0.05-1 mu m.
4. The method for preparing the wave-absorbing material based on agricultural and forestry waste recycling, which is disclosed by claim 3, is characterized in that: the method comprises the following steps:
(1) preparation of raw materials: cleaning walnut shell or xanthoceras sorbifolia Bunge shell, pulverizing, sieving, washing with water and ethanol, and drying;
(2) ultrasonic activation pretreatment: adding the dry shell powder and an activating agent into water, performing ultrasonic pretreatment, performing suction filtration and drying;
(3) step heating carbonization treatment: taking a proper amount of the pretreated material, putting the material into a tubular furnace, and carrying out carbonization reaction treatment in an inert gas atmosphere, wherein the carbonization process adopts stage programmed heating;
(4) and (3) freeze drying treatment: grinding the fluffy black solid obtained after the reaction by using an agate mortar, sequentially and repeatedly cleaning the fluffy black solid for a plurality of times by using different detergents, and freeze-drying the fluffy black solid by using a freeze-dryer to obtain a black powdery porous carbon wave-absorbing material prepared based on the biomass material.
5. The method for preparing the wave-absorbing material based on agricultural and forestry waste recycling, which is characterized by comprising the following steps: in the step (1), the sieve mesh of the crushed walnut shells is a 60-mesh sieve.
6. The method for preparing the wave-absorbing material based on agricultural and forestry waste recycling, which is characterized by comprising the following steps: in the step (2), the activating agent is alkali metal salt of alcohol including potassium hydroxide, sodium hydroxide, alkaline potassium salt, sodium salt and potassium ethoxide and sodium ethoxide; the mass ratio of the treated walnut shell powder to the carbon agent of the activating agent is 1: (1-3), wherein the solid-liquid mass ratio of the shell powder to the deionized water is 1: (10-15), the ultrasonic activation pretreatment time is 60min, and the drying temperature of the activated powder is 60 ℃.
7. The method for preparing the wave-absorbing material based on agricultural and forestry waste recycling, which is characterized by comprising the following steps: in the step (3), the stage heating carbonization treatment is divided into three stages:
a. a water removal and impurity removal stage, wherein the heating rate is 3 ℃/min, and the heating interval is room temperature to (200-250 ℃);
b. in the internal carbonization stage of the material, the temperature rise rate is 5 ℃/min, the temperature rise interval is (200-250 ℃) to (500-600 ℃), and the heat preservation time is (0.5-1) h;
c. in the secondary pore-forming stage, the temperature rise rate is 4 ℃/min, the temperature rise interval is (500-600) DEG C to (650-900) DEG C, and the carbonization pore-forming time is (1-3) h; and after the carbonization reaction is finished, the cooling rate is (2-5) DEG C/min.
8. The method for preparing the wave-absorbing material based on agricultural and forestry waste recycling, which is characterized by comprising the following steps: in the step (4), the used detergents are sequentially ionized water, hydrochloric acid and absolute ethyl alcohol, and are respectively washed for 2-3 times; the freeze drying time is (8-12) h.
9. The method for preparing the wave-absorbing material based on agricultural and forestry waste recycling, which is characterized by comprising the following steps: the inert gas used in the step (3) is argon.
10. The method for preparing the wave-absorbing material based on agricultural and forestry waste recycling, which is characterized by comprising the following steps: in the step (4), the concentration of the hydrochloric acid is (0.5-1) mol/L, and the dosage of the three lotions is (50-100) ml each time.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112408356A (en) * | 2020-10-10 | 2021-02-26 | 中国科学院金属研究所 | Preparation method of porous carbon microwave absorbent with saccharomycetes as pore-forming agent |
| CN113122184A (en) * | 2021-05-11 | 2021-07-16 | 盐城工学院 | Preparation method of biomass porous carbon wave-absorbing material |
| CN113942996A (en) * | 2021-11-06 | 2022-01-18 | 云南华谱量子材料有限公司 | Method and device for producing carbon material by microwave oxygen-free carbonization of pollution-free biomass |
| CN115305055A (en) * | 2022-08-03 | 2022-11-08 | 浙江大学 | Biomass-derived electromagnetic functional material and preparation method thereof |
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Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0028967A1 (en) * | 1979-11-09 | 1981-05-20 | Thomson-Csf | Process for producing materials absorbing hyperfrequency waves and absorbing material so obtained |
| CN101468797A (en) * | 2007-12-24 | 2009-07-01 | 徐文东 | Preparation of super active carbon material |
| CN104087326A (en) * | 2014-07-26 | 2014-10-08 | 安徽科技学院 | Method for preparing biochar by taking organic solid wastes of agriculture and forestry as raw materials in wet thermal cracking manner |
| CN104140100A (en) * | 2014-08-18 | 2014-11-12 | 福建师范大学 | Method for preparing micro-porous activated carbon for gas adsorption by virtue of vacuum freeze drying |
| RU2534801C1 (en) * | 2013-06-03 | 2014-12-10 | Федеральное государственное автономное образовательное учреждение высшего профессионального образования "Северный (Арктический) федеральный университет имени М.В. Ломоносова" (САФУ) | Method of obtaining activated coal |
| CN105197910A (en) * | 2015-07-20 | 2015-12-30 | 黑龙江大学 | Method for preparing porous carbon nanomaterial by taking biomass as carbon source |
| CN106276849A (en) * | 2016-07-28 | 2017-01-04 | 石河子大学 | A kind of preparation method of biomass carbon material |
| FI20165011A (en) * | 2016-01-08 | 2017-06-15 | Vapo Oy | A process for the preparation of low ash activated carbon |
| CN107640767A (en) * | 2017-10-20 | 2018-01-30 | 武汉工程大学 | One kind is used for cheap porous carbon materials of high-performance super capacitor and preparation method thereof |
| CN109133054A (en) * | 2018-11-05 | 2019-01-04 | 武汉大学 | A kind of mixed base activated carbon from activated sludge and preparation method thereof |
| CN109666451A (en) * | 2019-01-21 | 2019-04-23 | 淮北师范大学 | A method of absorbing material is prepared using biomass carbon source |
| CN110002445A (en) * | 2019-04-10 | 2019-07-12 | 浙江清风源环保科技有限公司 | The method for preparing high absorption property active carbon and activation using broomcorn straw |
| CN110182805A (en) * | 2019-06-22 | 2019-08-30 | 合肥煜创碳业有限公司 | A kind of preparation method of active carbon |
| CN110368971A (en) * | 2019-08-09 | 2019-10-25 | 陕西科技大学 | A kind of solid waste microwave-assisted depolymerization SiC based composite catalyst and preparation method thereof |
| CN110872110A (en) * | 2018-08-29 | 2020-03-10 | 陆莉莉 | Method for preparing biomass nano-pore carbon |
| CN111302339A (en) * | 2020-02-24 | 2020-06-19 | 山东大学 | Porous carbon material prepared from xanthoceras sorbifolia bunge shell residue waste as well as preparation method and application of porous carbon material |
-
2020
- 2020-07-12 CN CN202010666051.3A patent/CN111704134B/en active Active
Patent Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0028967A1 (en) * | 1979-11-09 | 1981-05-20 | Thomson-Csf | Process for producing materials absorbing hyperfrequency waves and absorbing material so obtained |
| CN101468797A (en) * | 2007-12-24 | 2009-07-01 | 徐文东 | Preparation of super active carbon material |
| RU2534801C1 (en) * | 2013-06-03 | 2014-12-10 | Федеральное государственное автономное образовательное учреждение высшего профессионального образования "Северный (Арктический) федеральный университет имени М.В. Ломоносова" (САФУ) | Method of obtaining activated coal |
| CN104087326A (en) * | 2014-07-26 | 2014-10-08 | 安徽科技学院 | Method for preparing biochar by taking organic solid wastes of agriculture and forestry as raw materials in wet thermal cracking manner |
| CN104140100A (en) * | 2014-08-18 | 2014-11-12 | 福建师范大学 | Method for preparing micro-porous activated carbon for gas adsorption by virtue of vacuum freeze drying |
| CN105197910A (en) * | 2015-07-20 | 2015-12-30 | 黑龙江大学 | Method for preparing porous carbon nanomaterial by taking biomass as carbon source |
| FI20165011A (en) * | 2016-01-08 | 2017-06-15 | Vapo Oy | A process for the preparation of low ash activated carbon |
| CN106276849A (en) * | 2016-07-28 | 2017-01-04 | 石河子大学 | A kind of preparation method of biomass carbon material |
| CN107640767A (en) * | 2017-10-20 | 2018-01-30 | 武汉工程大学 | One kind is used for cheap porous carbon materials of high-performance super capacitor and preparation method thereof |
| CN110872110A (en) * | 2018-08-29 | 2020-03-10 | 陆莉莉 | Method for preparing biomass nano-pore carbon |
| CN109133054A (en) * | 2018-11-05 | 2019-01-04 | 武汉大学 | A kind of mixed base activated carbon from activated sludge and preparation method thereof |
| CN109666451A (en) * | 2019-01-21 | 2019-04-23 | 淮北师范大学 | A method of absorbing material is prepared using biomass carbon source |
| CN110002445A (en) * | 2019-04-10 | 2019-07-12 | 浙江清风源环保科技有限公司 | The method for preparing high absorption property active carbon and activation using broomcorn straw |
| CN110182805A (en) * | 2019-06-22 | 2019-08-30 | 合肥煜创碳业有限公司 | A kind of preparation method of active carbon |
| CN110368971A (en) * | 2019-08-09 | 2019-10-25 | 陕西科技大学 | A kind of solid waste microwave-assisted depolymerization SiC based composite catalyst and preparation method thereof |
| CN111302339A (en) * | 2020-02-24 | 2020-06-19 | 山东大学 | Porous carbon material prepared from xanthoceras sorbifolia bunge shell residue waste as well as preparation method and application of porous carbon material |
Non-Patent Citations (12)
| Title |
|---|
| NOGI, M ET AL.: "Preparation of nanofibrillar carbon from chitin nanofibers", 《 JOURNAL OF MATERIALS CHEMISTRY A》 * |
| NOGI, M ET AL.: "Preparation of nanofibrillar carbon from chitin nanofibers", 《 JOURNAL OF MATERIALS CHEMISTRY A》, 23 July 2010 (2010-07-23) * |
| QIU, X ET AL.: "Lightweight and efficient microwave absorbing materials based on walnut shell-derived nano-porous carbon", 《NANOSCALE》 * |
| QIU, X ET AL.: "Lightweight and efficient microwave absorbing materials based on walnut shell-derived nano-porous carbon", 《NANOSCALE》, 14 July 2017 (2017-07-14), pages 7409 * |
| TIAN, WQ ET AL.: "Renewable graphene-like nitrogen-doped carbon nanosheets as supercapacitor electrodes with integrated high energy-power properties", 《JOURNAL OF MATERIALS CHEMISTRY A》 * |
| TIAN, WQ ET AL.: "Renewable graphene-like nitrogen-doped carbon nanosheets as supercapacitor electrodes with integrated high energy-power properties", 《JOURNAL OF MATERIALS CHEMISTRY A》, 14 June 2016 (2016-06-14) * |
| 孙凤坤: "柠条生物质的炭化活化及其性能研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 * |
| 孙凤坤: "柠条生物质的炭化活化及其性能研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》, 15 February 2016 (2016-02-15) * |
| 时亦飞: "枣木基活性炭的制备与改性及吸附甲醛研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 * |
| 时亦飞: "枣木基活性炭的制备与改性及吸附甲醛研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》, 15 October 2017 (2017-10-15) * |
| 李艳: "磷酸活化法核桃壳活性炭的结构与性能研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 * |
| 杨坤彬: ".升温速率对椰壳热解特性的影响及动力学分析", 《 农业工程学报 》 * |
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| CN112408356A (en) * | 2020-10-10 | 2021-02-26 | 中国科学院金属研究所 | Preparation method of porous carbon microwave absorbent with saccharomycetes as pore-forming agent |
| CN113122184A (en) * | 2021-05-11 | 2021-07-16 | 盐城工学院 | Preparation method of biomass porous carbon wave-absorbing material |
| CN113942996A (en) * | 2021-11-06 | 2022-01-18 | 云南华谱量子材料有限公司 | Method and device for producing carbon material by microwave oxygen-free carbonization of pollution-free biomass |
| CN113942996B (en) * | 2021-11-06 | 2023-09-19 | 云南华谱量子材料有限公司 | Method and device for producing carbon material by pollution-free biomass microwave oxygen-free carbonization |
| CN115305055A (en) * | 2022-08-03 | 2022-11-08 | 浙江大学 | Biomass-derived electromagnetic functional material and preparation method thereof |
| CN115744903A (en) * | 2022-11-15 | 2023-03-07 | 华侨大学 | Xanthoceras sorbifolia shell-derived porous carbon material and application thereof |
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