阅读说明：本技术 一种木质基微球及其活性炭球的制备方法 (Preparation method of wood-based microspheres and activated carbon spheres thereof ) 是由 马晓军 刘鑫 于 2021-01-05 设计创作，主要内容包括：本发明提供了一种木质基微球及其活性炭球的制备方法,具体地说,是一种利用木材等生物质资源液化物制备微米级活性炭球,本发明还涉及制备木质基微球球径调控,以及炭化、活化过程中的孔隙调控技术。采用本发明技术利用生物质材料液化物制备的木质基活性炭球,其比表面积可达到1299～2073m～2/g,微孔率可达75～90％。另外,该发明在制备过程中不添加任何醛类物质,价廉质优,避免了有毒物质产生。同时,该技术以生物质资源作为木质基活性炭球原料,降低了生产成本,在市场上具有很强的竞争力。(The invention provides a method for preparing a wood-based microsphere and an activated carbon sphere thereof, in particular to a method for preparing a micron-sized activated carbon sphere by using liquefied biomass resources such as wood and the like, and also relates to a sphere diameter regulation and control technology for preparing the wood-based microsphere and a pore regulation and control technology in the carbonization and activation processes. The specific surface area of the wood-based activated carbon ball prepared by the biomass material liquefied substance by adopting the technology can reach 1299-2073 m 2 The microporosity can reach 75-90%. In addition, no aldehyde substance is added in the preparation process, the price is low, the quality is high, and the generation of toxic substances is avoided. Meanwhile, the technology takes biomass resources as the raw material of the wood-based activated carbon balls, reduces the production cost and is applied to the production of the activated carbon ballsHas strong competitiveness in the market.)

1. A method for preparing wood-based microspheres, which is characterized by comprising the following steps:

the method comprises the following steps: crushing biomass raw materials such as wood and the like into powder, adding phenol, and carrying out liquefaction treatment by using phosphoric acid as a catalyst to obtain a liquefied substance;

step two: adding curing agent and concentration regulator in 7.5-17.5 wt% and 7-8.5 wt% of the liquefied matter, and stirring at room temperature for 1 hr to obtain completely dissolved mixed solution;

step three: adding the mixed solution into a dispersant which is preheated to 65 ℃ and has a mass fraction of 4-12%, stirring and heating to 130 ℃, reacting for 1.5h, washing, filtering and vacuum drying to obtain the wood-based microspheres.

2. The method according to claim 1, wherein the biomass raw material such as wood can be wood, bamboo, straw, plant fiber and the like, and the fineness of the powder is 20-80 meshes.

3. The method according to claim 1, wherein the step 1) is: crushing biomass raw materials such as wood and the like into powder, adding phenol which is 4-7 times of the weight of the raw materials and a phosphoric acid catalyst which is 6-8% of the weight of the added phenol and has the concentration of 85%, and stirring at the normal pressure and at the temperature of 150-160 ℃ for reaction for 2.5-3 h to obtain a liquefied product.

4. The method of claim 1, wherein the curing agent is hexamethylenetetramine, the dispersing agent is an aqueous solution of polyvinyl alcohol, and the concentration modifier is absolute ethanol.

5. A method for producing a woody-based activated carbon sphere, characterized in that the woody-based microspheres obtained in any one of claims 1 to 4 are subjected to curing, carbonization and activation treatment. The method comprises the following steps:

the method comprises the following steps: immersing the wood-based microspheres into an acid solution of aldehyde, heating to 95 ℃ at a heating rate of 35 ℃/h, and then curing at 95 ℃ for 0.5-2 h;

step two: after the solidified microspheres are washed clean by water, the solidified microspheres and KOH solid are evenly mixed and then are put into a carbonization furnace under the protection of N2 (N₂Flow rate is 100mL/min) is heated to 800 ℃ at the heating rate of 5 ℃/min, carbonized and activated for 1h, cooled to room temperature, fully washed by hydrochloric acid and deionized water, filtered and dried to obtain the wood-based activated micro carbon spheres.

6. The method of claim 5, wherein the acid solution of the aldehyde is an oxalic acid solution of formaldehyde or a hydrochloric acid solution of formaldehyde.

7. The method according to claim 5, wherein the acidic solution of the aldehyde is a solution containing 18.5% formaldehyde and 18.5% hydrochloric acid.

8. The method of claim 5, wherein the mass ratio of the cured microspheres to KOH is 1: 3.

9. Wood-based microspheres obtained by the process of any one of claims 1 to 4.

10. Wood-based activated carbon spheres obtained by the production of claims 5 to 9.

Technical Field

The invention provides a method for preparing a wood-based microsphere and an activated carbon sphere thereof, in particular to an activated carbon sphere prepared by using liquefied biomass resources such as wood and the like, and also relates to a sphere diameter regulation and control technology for preparing the wood-based microsphere and a pore regulation and control technology in the carbonization and activation processes.

Background

Activated carbon is a porous carbon material and is a nontoxic and harmless environment-friendly material, and is the most commonly used adsorption material at present due to the characteristics of high specific surface area, developed pore structure, low cost, easy regeneration and the like. Can be used for adsorbing toxic substances in tap water and air, and the adsorption effect of the adsorbent reaches the national standard. Developing countries consider their usage as one of the indicators that measure industrial development and living standard. It can be classified into fibrous, granular, powdery, spherical activated carbon, etc. according to its shape. Among them, spherical activated carbon is considered as a promising and valuable adsorbent for adsorbing harmful substances in a liquid phase or a gas phase. Besides the strong adsorption performance of the activated carbon, the activated carbon has many excellent characteristics: the surface is smooth, the sphere size is proper, the fluidity is good, the pore size distribution is easy to control, and the load density and the mechanical strength are higher, so that the nano-porous material is widely applied to the aspects of energy, food, biomedicine, chemical protection, super capacitors, aerospace and the like in recent years, and particularly has great attention in the field of blood purification materials.

At present, the spherical active carbon precursor materials are prepared from asphalt, phenolic resin, polystyrene polymer spheres and the like. Among them, the phenolic resin is a promising polymer precursor material for preparing activated carbon with high specific surface area due to low content of inorganic impurities and low ash content. However, the main raw materials of the activated carbon spheres prepared by taking the phenolic resin as a precursor are phenols (phenol, m-diphenol and the like) and aldehydes, and the activated carbon spheres are synthesized by relying on coal tar and petroleum residues. With the gradual depletion of petroleum resources and the continuous deterioration of ecological environment, people are eagerly looking for a biomass material to replace petroleum resources to prepare carbon materials. The wood is a natural ecological material, has wide resource source, can be continuously used and is a good source for preparing the activated carbon material. According to the expression of the forestry departments in China, a large amount of wood residues are not fully utilized every year in the world. If the wood residues are fully processed and utilized, the method has very important significance in the aspects of protecting the environment, saving petrochemical energy, improving the effective utilization of biomass materials, improving the use value of wood and the like.

The invention takes biomass resources such as wood and the like as raw materials, prepares wood-based microspheres by using a wood liquefied product and hexamethylenetetramine through an emulsion polymerization method, and prepares wood-based activated carbon spheres through a series of processes such as curing, carbonization and activation. Hexamethylenetetramine in the preparation raw materials can generate formaldehyde in situ to perform polymerization reaction with liquefied substances, so that the problems of energy consumption and environmental pollution are solved, biomass resources are fully utilized, and the electrochemical performance of the wood carbon spheres can be improved by a nitrogen source. The purpose of different sizes of sphere diameters and pores is achieved by adjusting the dosage of each reagent and the stirring speed in the preparation process. The micron carbon spheres prepared by the method are expected to eliminate ethylene in the storage and transportation processes of fruits and vegetables, replace small-package ethylene removing agents such as potassium permanganate and the like, and solve the problems of food safety, consumer trust and the like.

Disclosure of Invention

The invention aims to provide a method for preparing wood-based microspheres and an activated carbon sphere thereof by using biomass liquefied substances such as wood, and the main raw materials of the carbon sphere are mainly biomass resources such as wood.

The method comprises the steps of firstly liquefying biomass materials such as wood and the like to obtain a wood liquefied substance precursor, then adding a curing agent and a concentration regulator to prepare a uniformly mixed solution, adding the uniformly mixed solution into a dispersing agent, preparing wood-based microspheres with adjustable sphere diameters by controlling the concentration of the solvent and the stirring speed, and carrying out carbonization and activation after different curing processes to obtain the activated carbon spheres with different pores.

The wood-based microspheres and the cured microspheres mentioned in the present invention are different in that the cured microspheres are wood-based microspheres subjected to curing treatment.

Therefore, another objective of the present invention is to provide a method for regulating the sphere diameter and the pores of the activated carbon spheres for preparing the above wood-based microspheres.

The preparation method of the wood-based microspheres comprises the following steps:

the method comprises the following steps: crushing a biomass raw material into powder, adding phenol, and carrying out liquefaction treatment by using phosphoric acid as a catalyst to obtain a liquefied substance;

step two: adding curing agent and concentration regulator in 7.5-17.5 wt% and 7-8.5 wt% of the liquefied matter, and stirring at room temperature and 400rpm for 1 hr to obtain completely dissolved mixed solution;

step three: and adding the mixed solution into a dispersant which is preheated to 65 ℃ and has a mass fraction of 4-12%, stirring (350-800 rpm), heating to 130 ℃, reacting for 1.5h, washing, filtering and drying in vacuum to obtain the wood-based microspheres.

The weight of the added phenol is 4-7 times of that of the raw materials.

The adding amount of the phosphoric acid is 6 to 8 percent of the weight of the phenol, and the concentration of the phosphoric acid is 85 percent.

The liquefaction reaction is carried out for 2.5-3 hours under the condition of stirring at 150-160 ℃ under normal pressure.

The curing agent is hexamethylenetetramine.

The dispersant is polyvinyl alcohol aqueous solution.

The concentration regulator is absolute ethyl alcohol.

The biomass raw material is fir, and is crushed, wherein the fineness of raw material powder is 20-80 meshes.

The preparation method of the wood-based activated carbon ball comprises the following steps:

the method comprises the following steps: curing the prepared wood-based microspheres, wherein the curing method comprises the following steps: soaking the wood-based microspheres into a mixed solution of 18.5% of formaldehyde and 18.5% of hydrochloric acid, heating to 95 ℃ at a heating rate of 35 ℃/h, and then curing at 95 ℃ for 0.5-2 h;

step two: uniformly mixing the cured microspheres with KOH solid (microspheres: KOH is 1: 3), putting the mixture into a carbonization furnace, and adding N₂Under protection (N)₂Flow rate is 100mL/min) is heated to 800 ℃ at the heating rate of 5 ℃/min, and after carbonization and activation for 1h, the wood-based activated carbon ball is cooled to room temperature, fully washed by hydrochloric acid and deionized water, filtered and dried to obtain the wood-based activated carbon ball.

The wood-based activated carbon ball prepared by the method has the following characteristics:

the sphere diameter is as follows: 20 to 60 (mu m) in thickness,

specific surface area: 1299 to 2073 (m)²/g)，

Microporosity: 75 to 90 percent (%),

the yield is as follows: 40 to 60 percent (%),

average pore diameter: 1.95 to 2.38 (nm).

According to the characteristics of the biomass material, the inventor applies a liquefaction technology, an emulsion polymerization technology and a carbonization activation technology, and through a large amount of researches and experiments, the novel wood-based activated carbon ball prepared by using the biomass material liquefaction product by adopting the technology has the microporosity of 75-90 percent and has higher performance than that of the conventional product. In addition, the invention prepares the wood-based microspheres with different sphere diameters by controlling the proportion of each reagent, the stirring speed and other influencing factors. Meanwhile, the technology takes biomass resources as the raw material of the wood-based activated carbon sphere, does not add any aldehydes, reduces the production cost, avoids the generation of toxic substances, and has strong competitiveness in the market.

Drawings

FIG. 1 is a photograph of wood-based microspheres and activated carbon spheres thereof provided in an example of the present invention;

FIG. 2 is a scanning electron microscope image of a wood-based microsphere and an activated carbon sphere thereof provided by an embodiment of the present invention;

FIG. 3 is a nitrogen adsorption and desorption curve of wood-based activated carbon spheres with different curing times according to an embodiment of the present invention.

Detailed description of the invention

The preparation method of the wood-based microspheres comprises the following steps:

the method comprises the following steps: crushing biomass raw material Chinese fir into powder, adding phenol, and carrying out liquefaction treatment by using phosphoric acid as a catalyst to obtain a wood liquefaction product;

step two: adding hexamethylenetetramine and absolute ethyl alcohol according to 5-17.5 percent and 7-8.5 percent of the weight of the wood liquefied substance, and stirring at constant speed (400rpm) for 1 hour at room temperature to obtain a completely dissolved mixed solution;

step three: and adding the mixed solution into a polyvinyl alcohol aqueous solution which is preheated to 65 ℃ and has the mass fraction of 4-12%, stirring (350-800 rpm), heating to 130 ℃, reacting for 1.5h, washing, filtering and drying in vacuum to obtain the wood-based microspheres.

Through years of research and experiments, researchers of the invention find that the phosphoric acid has the best catalytic performance in the inorganic acid catalyst, so that the phosphoric acid is adopted to liquefy biomass raw materials such as wood, and the method specifically comprises the following steps: crushing a wood biomass raw material into powder, adding phenol which is 4-7 times of the weight of the raw material and a phosphoric acid catalyst which is 6-8% of the weight of the added phenol and has a concentration of 85%, stirring at normal pressure and reacting at 150-160 ℃ for 2.5-3 h to obtain a wood liquefaction product. The liquefaction process can be carried out in a conventional liquefaction plant.

The biomass raw materials such as the selectable wood can be wood, bamboo, straw, plant fiber and the like. The fineness of the raw material powder is preferably 20-80 meshes (the aperture of a mesh screen is 0.9-0.18 mm), and the biomass raw material can be crushed in a crusher.

The liquefaction treatment can be carried out in a conventional liquefaction apparatus.

Further, the preparation method of the wood-based activated carbon ball comprises the following steps:

the method comprises the following steps: curing the prepared wood-based microspheres, wherein the curing method comprises the following steps: soaking the wood-based microspheres into a mixed solution of 18.5% of formaldehyde and 18.5% of hydrochloric acid, heating to 95 ℃ at a heating rate of 35 ℃/h, and then curing at 95 ℃ for 0.5-2 h;

step two: uniformly mixing the cured microspheres with KOH solid (microspheres: KOH is 1: 3), putting the mixture into a carbonization furnace, and adding N₂Under protection (N)₂Flow rate is 100mL/min) is heated to 800 ℃ at the heating rate of 5 ℃/min, and after carbonization and activation for 1h, the wood-based activated carbon ball is cooled to room temperature, fully washed by hydrochloric acid and deionized water, filtered and dried to obtain the wood-based activated carbon ball.

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Example 1

Pulverizing fir into 80 mesh powder (mesh screen aperture 0.18mm), adding the wood powder, phenol 6 times of the weight of wood and catalyst phosphoric acid (phosphoric acid concentration 85%) in an amount of 8% of the amount of phenol added into a three-port glass bottle, placing in an oil bath preheated to 160 ℃, installing a condenser, starting a stirring device (rotating speed 1058rpm) for liquefaction, and obtaining a liquefied substance after the liquefaction time is 2.5 hours.

Adding hexamethylene tetramine accounting for 10% of the weight of the wood liquefied substance and absolute ethyl alcohol accounting for 7.6% of the weight of the wood liquefied substance into the wood liquefied substance, and stirring for 1 hour at a constant speed (400rpm) at room temperature to obtain a completely dissolved mixed solution.

And (3) dropwise adding the mixed solution into a polyvinyl alcohol aqueous solution which is preheated to 65 ℃ and has the mass fraction of 10%, stirring (650rpm), heating to 130 ℃, reacting for 1.5h, and washing, filtering and vacuum drying for multiple times to obtain the wood-based microspheres.

Immersing the wood-based microspheres into a mixed solution consisting of formaldehyde and hydrochloric acid with the concentration of 18.5%, and curing for 0.5h in the mixed solution at the temperature of 95 ℃ to obtain cured microspheres.

Uniformly mixing the cured microspheres with KOH solid (microspheres: KOH is 1: 3), putting the mixture into a carbonization furnace, and adding N₂Under protection (N)₂Flow rate is 100mL/min) is heated to 800 ℃ at the heating rate of 5 ℃/min, carbonization and activation are carried out for 1h, cooling to room temperature is carried out, hydrochloric acid and deionized water are used for fully washing, filtering and drying are carried out, and the wood-based activated carbon ball is obtained.

The sphere diameter of the prepared wood-based activated carbon sphere is as follows: 32-45 μm; specific surface area: 2073m²(ii)/g; microporosity: 75 percent; the yield is as follows: 40 percent.

Example 2

Pulverizing Chinese fir into 60 mesh powder, adding the Chinese fir powder and 5 times of phenol and 6% of catalyst phosphoric acid (phosphoric acid concentration is 85%) of the Chinese fir weight into a three-neck glass bottle, placing in an oil bath preheated to 150 ℃, installing a condenser, starting a stirring device (rotating speed 1058rpm) for liquefaction, and obtaining a liquefied substance, wherein the liquefaction time is 3 hours.

Adding hexamethylenetetramine accounting for 12.5% of the weight of the wood liquefied substance and absolute ethyl alcohol accounting for 8% of the weight of the wood liquefied substance into the wood liquefied substance, and stirring the mixture for 1 hour at a constant speed (400rpm) at 40 ℃ to obtain a completely dissolved mixed solution.

And (3) dropwise adding the mixed solution into a polyvinyl alcohol aqueous solution which is preheated to 65 ℃ and has a mass fraction of 4%, stirring (300rpm), heating to 130 ℃, reacting for 1.5h, washing for many times, filtering, and drying in vacuum to obtain the wood-based microspheres.

Immersing the wood-based microspheres into a mixed solution consisting of formaldehyde and hydrochloric acid with the concentration of 18.5%, and curing for 2 hours in the mixed solution at the temperature of 95 ℃ to obtain cured microspheres.

Uniformly mixing the cured microspheres with KOH solid (microspheres: KOH is 1: 3), putting the mixture into a carbonization furnace, and adding N₂Under protection (N)₂Flow rate is 100mL/min) is heated to 800 ℃ at the heating rate of 5 ℃/min, carbonization and activation are carried out for 1h, cooling to room temperature is carried out, hydrochloric acid and deionized water are used for fully washing, filtering and drying are carried out, and the wood-based activated carbon ball is obtained.

The sphere diameter of the prepared wood-based activated carbon sphere is as follows: 50-60 μm; specific surface area: 1744m²(ii)/g; microporosity: 78 percent; the yield is as follows: and 47 percent.

Example 3

Pulverizing Chinese fir into 40 mesh powder, adding the Chinese fir powder and phenol 4 times of the weight of the Chinese fir and catalyst phosphoric acid (phosphoric acid concentration is 85%) accounting for 8% of the addition of the phenol into a three-neck glass bottle, placing the three-neck glass bottle in an oil bath preheated to 160 ℃, installing a condenser, starting a stirring device (rotating speed of 1058rpm) for liquefaction, and obtaining a liquefied substance after the liquefaction time is 2.5 hours.

Adding hexamethylene tetramine accounting for 5% of the weight of the wood liquefied substance and absolute ethyl alcohol accounting for 7% of the weight of the wood liquefied substance into the wood liquefied substance, and stirring for 1 hour at a constant speed (400rpm) at the temperature of 30 ℃ to obtain a completely dissolved mixed solution.

And (3) dropwise adding the mixed solution into a polyvinyl alcohol aqueous solution which is preheated to 65 ℃ and has the mass fraction of 6%, stirring (500rpm), heating to 130 ℃, reacting for 1.5h, and washing, filtering and vacuum drying for multiple times to obtain the wood-based microspheres.

Immersing the wood-based microspheres into a mixed solution consisting of formaldehyde and hydrochloric acid with the concentration of 18.5%, heating to 95 ℃ at the heating rate of 35 ℃/h, and then curing at 95 ℃ for 0.5h to obtain the cured microspheres.

Uniformly mixing the cured microspheres with KOH solid (microspheres: KOH is 1: 3), putting the mixture into a carbonization furnace, and adding N₂Under protection (N)₂Flow rate is 100mL/min) is heated to 800 ℃ at the heating rate of 5 ℃/min, carbonization and activation are carried out for 1h, cooling to room temperature is carried out, hydrochloric acid and deionized water are used for fully washing, filtering and drying are carried out, and the wood-based activated carbon ball is obtained.

The sphere diameter of the prepared wood-based activated carbon sphere is as follows: 30 to 38 μm(ii) a Specific surface area: 1496m²(ii)/g; microporosity: 84%; the yield is as follows: 50 percent.

Example 4

Pulverizing Chinese fir into 80 mesh powder, adding the Chinese fir powder and 7 times of phenol and 6% of catalyst phosphoric acid (phosphoric acid concentration is 85%) of the Chinese fir weight into a three-neck glass bottle, placing in an oil bath preheated to 150 ℃, installing a condenser, starting a stirring device (rotating speed 1058rpm) for liquefaction, and obtaining a liquefied substance, wherein the liquefaction time is 3 hours.

Adding hexamethylene tetramine accounting for 17.5% of the weight of the wood liquefied substance and absolute ethyl alcohol accounting for 8.5% of the weight of the wood liquefied substance into the wood liquefied substance, and stirring for 1 hour at a constant speed (400rpm) at room temperature to obtain a completely dissolved mixed solution.

And (3) dropwise adding the mixed solution into a polyvinyl alcohol aqueous solution which is preheated to 65 ℃ and has the mass fraction of 12%, stirring (800rpm), heating to 130 ℃, reacting for 1.5h, and washing, filtering and vacuum drying for multiple times to obtain the wood-based microspheres.

Immersing the wood-based microspheres into a mixed solution consisting of formaldehyde and hydrochloric acid with the concentration of 18.5%, heating to 95 ℃ at the heating rate of 35 ℃/h, and then curing at 95 ℃ for 2h to obtain the cured microspheres.

Uniformly mixing the cured microspheres with KOH solid (microspheres: KOH is 1: 3), putting the mixture into a carbonization furnace, and adding N₂Under protection (N)₂Flow rate is 100mL/min) is heated to 800 ℃ at the heating rate of 5 ℃/min, carbonization and activation are carried out for 1h, cooling to room temperature is carried out, hydrochloric acid and deionized water are used for fully washing, filtering and drying are carried out, and the wood-based activated carbon ball is obtained.

The sphere diameter of the prepared wood-based activated carbon sphere is as follows: 22-30 μm; specific surface area: 1299m²(ii)/g; microporosity: 90 percent; the yield is as follows: 59 percent.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications or improvements may be made without departing from the spirit of the invention and within the scope of the claims.