TW201307201A - Activated carbon material - Google Patents

Abstract

The present invention provides a method of producing activated carbon from lignocellulosic material such as coconut shell. The method comprises the removal of accessible glucose units from the cellulose polysaccharides of the material prior to activation. The activated carbon material produced according to the method of the invention has a pore structure that is rich in micropores and mesopores. The material is suitable for use in tobacco smoke filtration, for example, in smoking article filters.

Description

Activated carbon material

The present invention is directed to a method of obtaining a high surface area activated carbon material. More particularly, the present invention provides a method of preparing activated carbon having a pore structure including mesopores and micropores.

Activated carbon materials are widely used in various adsorbents due to their large surface area, microporous structure and high surface reactivity. In particular, these materials are particularly effective for their adsorption because molecules of organic and inorganic compounds can bind to a large amount of carbon.

Activated carbon is typically made from materials including coconut shell, wood flour, peat, bone, coal char, resin, and related polymers. Because coconut shells are cheap, easy to obtain, and environmentally sustainable, they are particularly attractive as raw materials for the production of activated carbon. Activated carbon materials of high purity and high surface area can also be produced from coconut shells.

Coconut shell activated carbon has been applied to various processes and is widely used in vegetable oil and chemical solution refining and bleaching, water and air purification, solvent recovery, gold recycling and other processes. It is used in a variety of gas filters, including cigarette filters and gas masks.

The performance and adaptability of activated carbon materials as adsorbents in different environments depends on the physical properties of different materials, including particle shape and size, pore structure size, material surface area and so on. These different parameters can be controlled by manipulating the methods and conditions for making activated carbon.

Generally, the larger the surface area of the porous material, the greater the adsorption capacity of the material. As the surface area of the material increases, the density and structural integrity decrease. In addition, although increasing the number of pore structures and making smaller pore structures can increase the surface area of the material, when the pore structure size is close to the target molecular size, the target molecules will be less likely to enter the pore structure and adsorb to the material. This is especially true if the flow rate of the material to be filtered is higher than that of the activated carbon material.

In the present specification, according to the terminology used by those skilled in the art, the pore structure diameter of the adsorbent material is less than 2 nanometers (nm) and is called "microporous", and the pore structure having a diameter of 2 nm to 50 nm is called "mesopor". A pore structure having a diameter of more than 50 nm is called a macropores. Pore structures larger than 500 nm in diameter generally do not contribute significantly to the absorbency of porous materials.

It is known to reduce the amount of specific components of the smoke, and the porous carbon material can be incorporated into smoking articles and soot filters. The pore size distribution of porous carbon materials affects the adsorption characteristics, and it has been found that activated carbon materials rich in micropores and mesopores are most suitable for filtering inappropriate substances in gas phase tobacco smoke.

Coconut shells are widely used as raw materials for the production of activated carbon for smoking article filters. However, it is known that activated carbon made of coconut shell has the disadvantage of inconsistency or suboptimal regenerability, and is easy to be a completely microporous pore structure. For this reason, synthetic carbon made of a carbonized polymer and a synthetic resin is often used. These materials have excellent regenerability but are much more expensive than coconut shell carbon.

An object of the present invention is to provide a method for producing an activated carbon material which has both micropores and mesopores, so that tobacco smoke can be effectively filtered.

Another object of the present invention is to provide a method of making an activated carbon material that is suitable for use in a filter for smoking articles such as cigarettes.

A further object of the present invention is to provide a method of making an activated carbon material based on inexpensive and readily available materials and minimal processing steps, and the processing steps can be carried out using existing or simple manufacturing methods and equipment.

According to a first aspect of the invention, there is provided a process for the manufacture of activated carbon comprising the disintegration of cellulose from a feedstock.

The coconut shell is mainly composed of carbohydrates including cellulose, and it is surprisingly found that when a coconut shell material that has been treated to promote cellulose fragmentation is activated, an activated carbon material having a certain proportion of mesopores and micropores can be produced. The porous structure can improve the filtration effect of tobacco smoke gas phase poisons compared to microporous carbon. The recycled carbon of this activated carbon is also better than the activated carbon previously made from coconut shell.

Cellulose disintegration involves the removal of glucose units from the feedstock. For example, this involves removing or breaking down a glucose unit comprising a cellulose polysaccharide that makes up the material.

The process comprises fermentation of the starting material, which can be carried out at 20 ° C to 35 ° C and can take from 3 to 7 days. Alternatively, the method comprises culturing the starting material with a cellulase enzyme, which can be carried out at 50 ° C to 65 ° C.

The method involves the use of coconut shells as a raw material.

Preferably, the material is not carbonized prior to activation.

The method comprises making an activated carbon material having a pore structure comprising micropores and mesopores.

According to a second aspect of the present invention, an activated carbon material is provided which is obtained by a method of disintegrating cellulose containing a raw material.

According to a third aspect of the present invention, there is provided a filter for a smoking article comprising an activated carbon material which is obtained by a method of disintegrating cellulose containing a raw material.

According to a fourth aspect of the present invention, there is provided a smoking article comprising an activated carbon material which is obtained by a method of disintegrating cellulose containing a raw material.

Here, the term "smoking articles" includes any extractable products based on tobacco, tobacco derivatives, expanded tobacco, recombinant tobacco or tobacco substitutes, such as cigarettes, cigars and cigarillos.

The present invention relates to a process for the manufacture of activated carbon comprising the disintegration of cellulose from a feedstock.

Introduction and definition

Fig. 1 is a view showing the method for producing an activated carbon material from a coconut shell and the like, which has both micropores and mesopores.

Cellulose is the main structural component of many plants. It is a polysaccharide polymer comprising a linear glucose monosaccharide unit.

Fiber material 1 comprising coconut shell is composed of lignin, hemicellulose and cellulose and is commonly referred to as lignocellulosic material. The main function of lignin is to provide structural support. Lignin surrounds other material components, such as cellulose and hemicellulose molecules, to provide material strength (see Figure 1A).

Although cellulose is composed of long-chain glucose molecules 2, lignin coating will result in inaccessibility of glucose. Typically, to produce glucose from lignocellulosic materials, the materials are hydrolyzed using, for example, acid, enzymatic or thermochemical methods. However, the method according to a specific example of the invention does not comprise a hydrolysis step of extracting glucose from the lignocellulosic material. Therefore, glucose containing cellulose of a fibrous material is mostly inaccessible. This glucose is still incorporated into the wood fiber as a structural component of the material.

While the fibrous material has been ground (step I of Figure 1), where the material is decomposed arbitrarily into small pieces, the resulting microparticles have cellulose and, in particular, glucose unit 3, which appears on or near the surface of the material (see Figure 1B). These glucose units are therefore accessible and can be removed from the material. Removal of the glucose unit in this manner (step II) will form fine pits or cavities on the surface of the material 4 (see Figure 1C). The pit size may be equivalent to a single or a small number of glucose units. The diameter of the glucose molecules is about 0.5 nm, so the size of the pits is greater than about 0.5 nm to 5 nm.

Those skilled in the art will appreciate that this method is similar to the use of a pore structure forming agent to create pits during the manufacture of synthetic resins for conversion to activated carbon materials.

Upon subsequent activation of the material (step III), the existing fine pits, pore structures and voids in the material are opened and enlarged to form micropores 5 and mesopores 6 in the material (see Figure 1D).

In accordance with the above, "cellulose disintegration" as used herein refers to any method by which glucose units can be removed from cellulose. In particular, "cellulose fragmentation" encompasses the removal of glucose using a fermentation process, cellulase enzymes, or other methods that remove glucose from cellulose.

raw material

In one embodiment of the invention, the fibrous material used in the process is a coconut shell. Other suitable materials include other nuts and nut shells (such as pistachio and walnut shell), and other fruit waste (such as peach or apricot kernel), palm kernel or olive waste. Other organics, including untreated wheat straw and wood, are also suitable for use in the present invention. In general, any organic material comprising a large proportion of fibrous material will be suitable for use in the present invention.

The material is preferably a coconut shell because it can be used to make materials with a strong structure and a large surface area. It is also cheap and available everywhere, and is essentially waste.

grinding

In one embodiment of the invention, the fibrous material is ground prior to fermentation and activation. By reducing the size of the fragments of the fibrous material, a larger surface area can be provided for cellulose disintegration. More specifically, the surface of the material will contain cellulose molecules, whereby the glucose unit can be removed.

Those skilled in the art will appreciate that different milling methods are suitable for use with different fiber materials. Generally, it can be ground by any suitable method, including grinding, milling, chopping, compacting, or any other means of reducing solid material to small fragments. As for the coconut shell material, the preferred method of grinding is mashing and cutting.

After grinding, select the particles with the best size. The size can be selected by any suitable method, for example, screening of the ground material.

The preferred average particle diameter of the ground material is from 10 micrometers (μm) to 5000 μm, more preferably from 50 μm to 1,500 μm. The particle size is preferably from 200 μm to 900 μm.

Cellulase treatment

Cellulase refers to an enzyme that catalyzes the degradation (hydrolysis) of cellulose and the removal of glucose units. Several cellulases with different structural and mechanical effects are known. Some different cellulose degradation mechanisms are known to be catalyzed by different cellulases. These include exo- and endocellulases, which respectively catalyze the removal of glucose units from the ends of the cellulose chain, or internal division of the cellulose chains.

Mixtures of different cellulases can be used.

A preferred cellulase enzyme JN-100 acid cellulase for use in the present invention. When this enzyme is employed, the cellulase treatment is usually carried out at 40 ° C to 70 ° C, more preferably 50 ° C to 65 ° C, and the optimum culture system is carried out at about 60 ° C. The pH is also important, and the culture is carried out at a pH of 4.0 to 6.0, preferably at a pH of 4.5 to 5.0.

Fermentation

Fermentation is a chemical process in which an organic compound (and in particular a sugar) decomposes in the absence of oxygen to produce alcohol and carbon dioxide. The fermentation of glucose into carbon dioxide and alcohol is well known as the process carried out by yeast and anaerobic bacteria.

For example, the fiber material of coconut shell is composed of glucose molecules, so it can be fermented into ethanol as an alternative fuel. The fermentation process of the invention can be carried out by any anaerobic organism. Yeast is particularly widely used in glucose fermentation, for example in the production of bread, beer and alcohol biofuels. In particular, brewer's yeast for the industry and widely applicable method claimed herein. Generally, any yeast that will ferment glucose can be used in the methods claimed herein. A preferred yeast is Saccharomyces cerevisiae .

The amount of yeast is usually from about 2% by weight to 40% by weight, preferably, the amount of yeast is from 5% by weight to 20% by weight.

Recently, bacteria have received high attention from researchers because of their fermentation speed. Usually, bacteria can be fermented in a few minutes, while the same process yeast can take hours. Any bacteria that can ferment glucose can be applied to the methods claimed herein.

Since the fermentation is an anaerobic process, this process obviously has to be carried out in an oxygen-free environment. In a typical configuration, the yeast is first cultivated in the culture medium and then mixed with the fibrous material. This mixture is then incubated at the appropriate fermentation temperature and maintained at this temperature during the fermentation.

Any suitable culture solution can be used to culture the yeast. In particular, preferred culture fluids include malt extract media, potato media and/or glucose media.

In the case of yeast, the fermentation process is usually carried out at 15 ° C to 40 ° C, more preferably 20 ° C to 35 ° C. The optimum fermentation is carried out at about 25 °C.

The pH of the fermentation process is very important. Preferably, the acidity of the reaction medium is from pH 4 to pH 4.5 at the start of the fermentation, and a preferred initial pH is about pH 4.3. During the fermentation, the acidity of the reaction medium is increased to pH 3.3 to pH 4.0. Preferably, the pH at the end of the fermentation is about 3.6.

Processing time

Since most of the cellulose in the fiber material cannot be broken, the disintegration process can only be carried out until all available glucose molecules are removed. Thus, regardless of the culture time, the amount of yeast or enzyme added, the culture temperature, etc., the disintegration process will naturally end. Therefore, it is worthless to culture the material for more than enough time to remove all available glucose.

On the other hand, it is important to remove as much glucose as possible, as this will ultimately equate to the medium porosity of the active material. Usually, when yeast is used, the fibrous material is fermented for 2 to 12 days, preferably for 3 to 7 days. The material is optimally fermented for about 3 days.

When cellulase is used, the fibrous material is treated for 1 to 14 days, preferably for 2 to 10 days, and the material is preferably treated for about 3 to 6 days.

washing

Following the cellulose disintegration process, the material is washed to remove any residual yeast or enzyme, and any other improper materials, such as glucose or glucose fermentation products. In addition, trace amounts of yeast, enzymes or other undesirable substances can interfere with the carbonization or activation of the material. It is preferred to use water to wash the material.

The material can be washed by any suitable method. A typical washing procedure involves mixing the material with distilled water, allowing the material to settle, and then removing the water by decantation. This washing method can be repeated as 5 to 12 cycles, preferably about 8 cycles.

After washing, the material can be dried by any suitable method. Preferably, the material is dried overnight at 80 °C.

After washing, the material quality is reduced to as much as 10%. Typically, the mass is reduced by about 2% to 4%.

The disintegrated coconut shell color is lighter than the starting material.

Carbonization

Carbonization refers to the process in which a material is pyrolyzed without air and removes most of the elements other than carbon like a volatile compound.

The advantage of the method claimed herein is that the material does not need to be carbonized.

In some cases, however, the material is preferably carbonized. Carbonization can be achieved by any suitable method, which is well known to those skilled in the art. Suitable methods include pit erosion, drum casting, and dry distillation. The carbonization method using phosphoric acid (H ₃ PO ₄ ) or zinc chloride (ZnCl ₂ ) can increase the proportion of micropores in the material and also increase the proportion of carbon in the material. However, this method also increases the proportion of improper inorganic compounds in the carbon material. Inorganic compounds can be removed using intensive washing procedures.

activation

Carbon material activation refers to the process in which existing pore structures and pits in a material are opened and expanded to form a material having a large surface area. Taking the method claimed herein as an example, the pores, pits, and pore structures caused by cellulose cleavage and removal of glucose molecules from cellulose will expand during the activation process to provide a material rich in micropores and mesopores.

Without wishing to be bound by any theory, it is known that the pores and pits created on the surface of the material due to cellulose cleavage and removal of glucose will expand during the activation process to form mesopores. Therefore, the medium porosity of the material can be adjusted by adjusting the degree of cellulose disintegration of the fiber material.

The material can be activated by any means, and those skilled in the art will appreciate that both physical and chemical means are suitable. Preferably, the physical means activating material; most preferably, nitrogen and steam or carbon dioxide (CO ₂₎ to the active material.

In one embodiment of the invention, the material is activated by reaction with steam in a controlled kiln (e.g., a rotary kiln) under a controlled nitrogen atmosphere. The temperature of the activation process is important. If the temperature is too low, the reaction becomes too slow and uneconomical. On the other hand, if the temperature is too high, the reaction becomes diffusion control, resulting in material loss.

The activation of the material can be carried out at 700 ° C to 1100 ° C, and the activation is preferably carried out at 800 ° C to 1000 ° C. The material is preferably activated at about 850 °C.

The activation process is preferably carried out for 30 minutes to 4 hours. The material is optimally activated for 1 hour.

In an alternate embodiment, the material is activated by reaction with carbon dioxide. In this case, the material activation can be carried out at 700 ° C to 1100 ° C, and the activation is preferably carried out at 800 ° C to 1000 ° C. The material is preferably activated at about 900 °C.

The activation process is preferably carried out for 1 to 4 hours. The material is optimally activated for 2 hours.

Chemical activation methods can be employed, such as using KOH or ZnCl ₂ to activate the material. However, chemical activation methods may cause chemicals to deposit in carbon materials, which is undesirable. Chemicals can be removed using intensive washing procedures.

Particle size

After activation, the particle size of the material is reduced by 10% to 40%, and the particle size of the material is preferably reduced by 20% to 30%.

Materials made in accordance with the method of the present invention will have small enough particles to provide a large surface area for filtering smoke. However, the activated carbon material particles should be large enough so that the smoke drawn through the filter is not limited. It is also important that the particles are large enough not to be entrained in the smoke and to be drawn through the filter and inhaled by the smoker. Although carbon is harmless, inhaling the fragments will still make the user unhappy.

On the other hand, if the fragment is too large, the surface area to volume ratio of the fragment will result in a decrease in filtration efficiency.

After considering these factors, the particle size of the activated carbon produced by the method is preferably from 10 μm to 4000 μm. The average particle diameter is preferably from 50 μm to 2000 μm, more preferably from 100 μm to 1000 μm. The average particle diameter of the activated carbon is preferably from 150 μm to 550 μm.

Surface area

The change in the volume of nitrogen adsorbed by the material at a certain temperature relative to the partial pressure of nitrogen is measured to estimate the surface area of the activated carbon material. The values produced by the mathematical model analysis created by Brunauer, Emmett, and Teller are called BET surface areas.

The activated carbon material produced by the process of the invention has a BET surface area of at least 800 square meters per gram (m ² /g), preferably at least 900 m ² /g, and a period of at least 1000, 1100, 1150, 1200, 1250, 1300 Or 1350m ² /g. The carbon materials produced by the process of the invention typically have a BET surface area value of up to about 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1400, 1500, 1600, 1700, 1800 or 1900 m ² /g. BET surface area of 1000m ² / g to 1500m ² / porous carbon-based material is preferred by g, and a surface area of 1200m ² / g are preferred material systems to 1400m ² / g of.

Porosity

The relative volumes of micropores, mesopores and macropores in activated carbon materials were estimated using conventional nitrogen adsorption and mercury porosimetry techniques. Mercury wells are used to estimate the volume of mesopores and macropores. Nitrogen adsorption uses a so-called BJH mathematical model to estimate the volume of micropores and mesopores. However, because the theoretical basis of the estimation is different, the values obtained by the two methods cannot be directly compared.

The activated carbon material formed by the method of the present invention has a pore structure including mesopores and micropores. In the preferred carbon material of the present invention, the pore volume (estimated by nitrogen adsorption) of at least 20% but not more than 65% is mesopores. The typical minimum value of the mesopore volume is 25%, 35% or 45% based on the total percentage of the microporous to mesoporous volume of the carbon material of the present invention. Typical volume maxima are 55%, 60% or 65%. Preferably, the mesoporous volume of the carbon material of the present invention is from 25% to 55% of the total volume of mesopores and micropores.

The porous carbon material of the present invention preferably has a pore volume (estimated by nitrogen adsorption) of at least 0.4 cubic centimeters per gram (cm ³ /g) for a period of at least 0.5, 0.6, 0.7, 0.8 or 0.9 cm ³ /g. A carbon material having a pore volume of at least 0.5 cm ³ /g is particularly suitable as an adsorbent for tobacco smoke. A carbon material having a pore volume much larger than a preferred value may have a low density and thus is less likely to be handled in a cigarette production facility. Therefore, such carbon materials are disadvantageous for use in cigarettes or soot filters.

density

The pore structure of activated carbon materials is closely related to density. Generally, the larger the pore volume of the material, the lower the density.

The overall density of the activated carbon material produced by the process of the invention is preferably greater than 0.25 g/cm ³ , more preferably greater than 0.3 g/cm ³ . The overall density of the activated carbon material is up to 0.7 g/cm ³ , 0.6 g/cm ³ or 0.5 g/cm ³ .

The true density of the material is greater than 0.4 g/cm ³ , preferably greater than 0.45 g/cm ³ . The true density of the activated carbon material is up to 0.55 g/cm ³ , 0.60 g/cm ³ or 0.65 g/cm ³ .

Incorporating activated carbon material into the filter

Figure 2 shows the smoking article 7 containing the filter 8.

The filter 8 is substantially cylindrical and has a mouth end 9 and a smoking material end 10. The filter comprises three segments, wherein the segments at the mouth end 11 and the smoking material end 12 comprise a filter material packing. The intermediate section of the filter contains a cavity 13 containing the activated carbon material of the present invention.

The filter 8 is wrapped around its surrounding surface by a stuffing package 14. The smoking article further comprises a cylindrical drawable material rod (in this case, tobacco 15) aligned with the filter 8 such that the end of the tobacco rod 15 abuts the end of the filter 8. The tobacco rod is combined with the filter 8 from the outer paper 16 in a conventional manner.

Obviously, the more activated carbon in the filter, the stronger the filter capacity. However, it is important that the filter does not contain too much activated carbon. For example, when the density of activated carbon charged into the filter is too large, it may hinder the flow path, and the smoker will feel unsatisfactory and extremely unsatisfactory. In addition, if the size of the cavity is increased and the amount of packing material of the filter is correspondingly reduced, the granular material in the smoke cannot be sufficiently filtered.

In addition to the specific embodiment of the cavity filter shown in Figure 2, there are a number of ways in which activated carbon can be incorporated into the filter. In some embodiments, the filter comprises a Dalmatian type filter in which activated carbon is distributed throughout the filter material. In other embodiments, the filter comprises a sheet filter wherein the activated carbon material is attached to the stuffer or outer layer. In a further embodiment, the activated carbon is incorporated into the filter in combination or in two or more of the above methods.

The amount of activated carbon incorporated into the filter depends on the type of filter. For example, a filter for use with an ultrafine cigarette usually contains 12 to 20 milligrams (mg) of activated carbon, preferably 16 mg. On the other hand, the filter for use with an oversized cigarette usually contains 20 to 80 mg, preferably 30 to 60 mg. Typically, the filter comprises from 5 mg to 120 mg of activated carbon, preferably from 10 mg to 100 mg of activated carbon. In the specific example shown in Figure 1, the filter comprises 60 mg of activated carbon material made according to the process of the invention.

The above describes preferred embodiments of the invention. It will be appreciated by those skilled in the art that various changes and modifications can be made without departing from the scope of the invention.

Example Example 1

A first sample of the activated carbon material (referred to as F1) is prepared from the coconut shell using a method comprising yeast fermentation of the feedstock according to the method of the invention.

In short, the coconut shell material is ground by chopping and cutting, followed by thorough washing with water to remove any contaminants and dust from the grinding. The washing was carried out at room temperature using distilled water, and a total of 8 washing cycles were performed.

Instead of carbonizing the coconut shell material, the yeast yeast yeast (taken from Angel Yeast, China) was used to ferment the granular coconut shell material.

Containing glucose (1 g), sodium sulfate (Na ₂ SO ₄ , 0.2 g), sodium dihydrogen phosphate (NaH ₂ PO ₄ , 0.1 g), potassium chloride (KCl, 0.05 g), per 100 ml (ml), Yeast was preliminarily cultured in a glucose medium of MgSO ₄ ‧7H ₂ O (0.05 g), iron nitrate (Fe(NO ₃ ) ₃ , 0.1 g) and distilled water.

The granulated coconut shell material was fermented in water at 25 ° C for 3 days. When the fermentation was started, the pH of the medium was 4.3. After the fermentation, the pH was 3.6.

After the fermentation, the material was dried and then activated at 850 ° C for 1 hour in steam under a nitrogen atmosphere.

Thus, about 10 grams of activated carbon material can be obtained.

Example 2

A second sample of the activated carbon material (referred to as F2) was prepared by the same method as described above, the only difference being that the sample was activated with CO ₂ for 2 hours at 900 °C.

Example 3

Various physical properties of the activated carbon material samples F1 and F2 were evaluated.

A control material (Ecosorb CX) was used as a reference. This is a standard commercially available activated carbon made from coconut shell and activated by steam. The Ecosorb CX activated carbon material has a completely microporous structure.

The synthesis conditions and fabric parameters of the activated carbon material samples are listed in Table 1. The test parameters were BET surface area (S _BET ), total pore volume (V _overall ), total pore volume of the _micropores (V _micropores ), non-microporous total pore volume (V _other ), and average pore diameter (D _peak ).

Figure 3 shows the adsorption isotherm and BJH plots for two porous carbon samples.

Those skilled in the art can know from the adsorption isotherm curve that in addition to the micropores, the activated carbon materials F1 and F2 also contain pores having an average diameter of 3.9 nm and 3.8 nm, respectively. These materials have both microporous and mesoporous structures and are therefore suitable for tobacco smoke filtration.

Example 4

Some activated carbon material samples C1 to C6 were prepared from the coconut shell using a cellulase treatment method containing the raw materials.

In short, the coconut shell material is ground by chopping and cutting, followed by thorough washing with water to remove any contaminants and dust from the grinding. The washing was carried out at room temperature using distilled water, and a total of 8 washing cycles were performed.

The pulverized coconut shell material is classified and selected into particles having a particle diameter of 1 to 5 mm.

About 3.0 g of the coconut shell material was incubated with 30 g of a cellulase solution having a concentration of 10 g/dm ³ . The culture line was carried out at 55 ° C for 6 days.

After cellulase treatment, the material was washed 5 times with distilled water and then dried at 50 °C.

Finally, activate the material. In the first stage, the temperature was increased to 400 ° C at a rate of 3 ° C / minute. The material was incubated at this temperature for 60 minutes. In the second stage, the temperature was further increased to 800 ° C at a rate of 5 ° C / minute. Once the temperature reached 800 ° C, the nitrogen atmosphere was converted to a nitrogen/steam atmosphere and the material was incubated for 60 minutes under these conditions. The feed water speed was 0.12 ml/min.

Sample C2 was produced in the same manner as Sample C1 except that the coconut shell material was microwaved at 90 ° C for 120 minutes before cellulase treatment.

Sample C3 was produced in the same manner as Sample C1 except that the cellulase treatment was carried out at 60 ° C for 3 days. The second stage of C3 activation was carried out at 850 ° C for 60 minutes.

Sample C4 was produced in the same manner as Sample C3 except that the concentration of the cellulase solution was 20 g/dm ³ .

Sample C5 was produced in the same manner as Sample C3 except that the cellulase treatment system was carried out for 6 days.

Sample C6 was produced in the same manner as Sample C3 except that the cellulase treatment system was carried out for 12 days.

Example 5

Various physical properties of the activated carbon material samples C1 to C6 were evaluated.

The synthesis conditions and fabric parameters of the activated carbon material samples are listed in Table 2. In addition to the parameters listed in Table 1, it also provides the surface area of the material in the _micropores (S _micropores ).

Figure 4 shows the adsorption isotherm and BJH plots for two porous carbon samples.

Those skilled in the art can know from the adsorption isotherm curve that in addition to the micropores, the activated carbon materials C1 to C6 also contain pores having an average diameter of 4.01 nm to 8.82 nm. These materials have both microporous and mesoporous structures and are therefore suitable for tobacco smoke filtration.

Example 6

The adsorption capacity of the carbon sample of both microporous and mesoporous to the selected aerosol gas phase poison was evaluated.

Similar to Figure 2, about 60 mg of sample F1 or F2 was used for the cavity filter. The filter was attached to a tobacco rod and the resulting smoking article was conditioned at 22 ° C and 60% relative humidity for 3 weeks prior to smoking.

The smoke was analyzed according to the International Organization for Standardization (ISO) method of collecting smoke, which contained a smoked group that took 35 ml every 60 seconds for 2 seconds. The composition of the smoke drawn through each filter is then evaluated.

A control smoking article containing 60 mg of Ecosorb CX was used. In addition, smoking articles containing the same filter but no adsorbent were also studied under the same conditions.

The results of the analysis are shown in Table 3.

Example 7

The percentage reductions in the different components of tobacco tobacco are listed in Table 4. Evaluation of activated carbon samples F1, F2 reduced the effectiveness of various organic molecules in tobacco smoke and compared to Ecosorb CX and empty filters.

In summary, it can be seen from the above that the activated carbon material produced by the fermentation of the coconut shell material has a pore structure rich in micropores and mesopores. This pore structure is related to the ability of the material to remove improper organic molecules from tobacco smoke, as both activated carbons F1 and F2 are more effective at removing chemicals than the only microporous Ecosorb CX.

In addition, the vapor-activated sample F1 has a medium porosity which is larger than F2 and therefore has a greater ability to remove organic chemicals.

In summary, the examples indicate that the activated carbon material sample produced by the method of the present invention provides a porous carbon material that is suitable for incorporation into a tobacco smoke filter.

1. . . Fiber material

2. . . Glucose molecule

3. . . Glucose unit

4. . . material

5. . . Microporous

6. . . Middle hole

7. . . Smoking items

8. . . filter

9,11. . . Mouth end

10, 12. . . Smoking material end

13. . . Cavity

14. . . Packing package

15. . . tobacco

16. . . Outer paper

For a fuller understanding of the invention, reference is made to the drawings in which:

Figure 1 is a schematic view of the present invention.

Figure 2 depicts a partially expanded filter cigarette comprising a filter in accordance with an embodiment of the present invention. This figure is not drawn to scale.

Fig. 3 shows adsorption isotherms and BJH patterns of two porous carbon samples F1, F2 prepared in Example 1 and Example 2.

Figure 4 shows the adsorption isotherm curves and BJH patterns of the porous carbon samples C1 to C6 prepared in Example 4.

1. . . Fiber material

2. . . Glucose molecule

3. . . Glucose unit

4. . . material

5. . . Microporous

6. . . Middle hole

Claims (14)

A method of making activated carbon comprising cellulose disintegration of a fibrous material. The method of claim 1, wherein the disintegration is carried out in the original state of the fibrous material. The method of claim 1 or 2, wherein the fibrous material is a coconut shell. The method of any one of claims 1 to 3 wherein the cellulose disintegration comprises removing glucose from the fibrous material. The method of any one of claims 1 to 4, wherein the method comprises culturing the fibrous material with cellulase. The method of claim 5, wherein the culture is carried out at a temperature of from 50 ° C to 65 ° C. The method of any one of claims 1 to 4, wherein the method comprises fermenting the fibrous material. The method of claim 7, wherein the fibrous material is fermented for 3 to 7 days. The method of claim 7 or 8, wherein the fermentation is carried out at a temperature of from 20 ° C to 35 ° C. The method of any one of claims 1 to 9, wherein the material is not carbonized prior to activation. The method of any one of claims 1 to 10, wherein the material obtained has a pore structure comprising a mesopores and micropores. An activated carbon material obtained by the method of any one of claims 1 to 11. A filter for smoking articles, comprising an activated carbon material obtained by the method of any one of claims 1 to 11. A smoking article comprising an activated carbon material produced by the method of any one of claims 1 to 11.