WO2011148156A1 - Method of preparing porous carbon - Google Patents
Method of preparing porous carbon Download PDFInfo
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- WO2011148156A1 WO2011148156A1 PCT/GB2011/050882 GB2011050882W WO2011148156A1 WO 2011148156 A1 WO2011148156 A1 WO 2011148156A1 GB 2011050882 W GB2011050882 W GB 2011050882W WO 2011148156 A1 WO2011148156 A1 WO 2011148156A1
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- WIPO (PCT)
- Prior art keywords
- carbon
- activation
- activated
- solution
- alkali solution
- Prior art date
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 122
- 238000000034 method Methods 0.000 title claims abstract description 49
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 45
- 239000000463 material Substances 0.000 claims abstract description 55
- 239000003513 alkali Substances 0.000 claims abstract description 35
- 230000004913 activation Effects 0.000 claims abstract description 31
- 239000007858 starting material Substances 0.000 claims abstract description 24
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 20
- 239000007833 carbon precursor Substances 0.000 claims abstract description 16
- 230000003213 activating effect Effects 0.000 claims abstract description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 93
- 239000000243 solution Substances 0.000 claims description 46
- 235000013162 Cocos nucifera Nutrition 0.000 claims description 21
- 244000060011 Cocos nucifera Species 0.000 claims description 21
- 238000011282 treatment Methods 0.000 claims description 18
- 238000005406 washing Methods 0.000 claims description 14
- 238000002203 pretreatment Methods 0.000 claims description 8
- 230000000391 smoking effect Effects 0.000 claims description 8
- 235000003447 Pistacia vera Nutrition 0.000 claims description 4
- 240000006711 Pistacia vera Species 0.000 claims description 4
- 239000012266 salt solution Substances 0.000 claims description 4
- 235000017166 Bambusa arundinacea Nutrition 0.000 claims description 3
- 235000017491 Bambusa tulda Nutrition 0.000 claims description 3
- 244000082204 Phyllostachys viridis Species 0.000 claims description 3
- 235000015334 Phyllostachys viridis Nutrition 0.000 claims description 3
- 239000011425 bamboo Substances 0.000 claims description 3
- 239000012978 lignocellulosic material Substances 0.000 claims description 3
- 239000002023 wood Substances 0.000 claims description 3
- 239000005569 Iron sulphate Substances 0.000 claims description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 2
- 235000020233 pistachio Nutrition 0.000 claims description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims 1
- 239000000779 smoke Substances 0.000 abstract description 15
- 239000003463 adsorbent Substances 0.000 abstract description 7
- 238000001914 filtration Methods 0.000 abstract description 6
- 238000001994 activation Methods 0.000 description 38
- 239000011148 porous material Substances 0.000 description 27
- 238000001179 sorption measurement Methods 0.000 description 25
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 18
- 239000000523 sample Substances 0.000 description 10
- 229910052757 nitrogen Inorganic materials 0.000 description 9
- 239000000047 product Substances 0.000 description 9
- 229910002092 carbon dioxide Inorganic materials 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000003763 carbonization Methods 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 229910001415 sodium ion Inorganic materials 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 231100000167 toxic agent Toxicity 0.000 description 4
- 239000003440 toxic substance Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 241000208125 Nicotiana Species 0.000 description 3
- 235000002637 Nicotiana tabacum Nutrition 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 239000002243 precursor Substances 0.000 description 3
- 230000007420 reactivation Effects 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- 229910000029 sodium carbonate Inorganic materials 0.000 description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- 229920002488 Hemicellulose Polymers 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 235000019504 cigarettes Nutrition 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000002309 gasification Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229920005610 lignin Polymers 0.000 description 2
- 238000013178 mathematical model Methods 0.000 description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 238000002459 porosimetry Methods 0.000 description 2
- 229910000028 potassium bicarbonate Inorganic materials 0.000 description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 description 2
- KWYUFKZDYYNOTN-UHFFFAOYSA-M potassium hydroxide Inorganic materials [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- -1 bone Substances 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000013068 control sample Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 231100001240 inorganic pollutant Toxicity 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052743 krypton Inorganic materials 0.000 description 1
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 230000001151 other effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000003415 peat Substances 0.000 description 1
- 238000004375 physisorption Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000013341 scale-up Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
- A24D3/00—Tobacco smoke filters, e.g. filter-tips, filtering inserts; Filters specially adapted for simulated smoking devices; Mouthpieces for cigars or cigarettes
- A24D3/06—Use of materials for tobacco smoke filters
- A24D3/16—Use of materials for tobacco smoke filters of inorganic materials
- A24D3/163—Carbon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/30—Active carbon
- C01B32/312—Preparation
- C01B32/318—Preparation characterised by the starting materials
- C01B32/324—Preparation characterised by the starting materials from waste materials, e.g. tyres or spent sulfite pulp liquor
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/30—Active carbon
- C01B32/354—After-treatment
Definitions
- the present invention relates to methods for preparing porous carbon material, and in particular to methods designed to produce porous carbon with micropores and mesopores.
- the resultant porous carbon is particularly useful for smoke filtration in smoking articles, as the porous structure can provide improved adsorption of smoke vapour phase toxicants compared to conventional activated carbon.
- Filtration is used to reduce certain particulates and/ or vapour phase constituents of tobacco smoke inhaled during smoking. It is important that this is achieved without removing significant levels of other components, such as certain organoleptic components, thereby degrading the quality or taste of the product.
- Smoking article filters may include porous carbon materials (dispersed throughout filter material or in a cavity in the filter) to adsorb certain smoke constituents, typically by physisorption.
- porous carbon materials can be made from the carbonized form of many different organic materials, most commonly plant-based materials such as coconut shell.
- Activated carbon materials have become widely used as versatile adsorbents owing to their large surface area, microporous structure, and high degree of surface reactivity. In particular, these materials are especially effective in the adsorption of organic and inorganic pollutants due to the high capacity of organic molecules to bind to carbon.
- Activated carbons are commonly produced from materials including coconut shell, wood powder, peat, bone, coal tar, resins and related polymers.
- Coconut shell is particularly attractive as a raw material for the production of activated carbon because it is cheap and readily available, and is also environmentally sustainable. Furthermore, it is possible to produce from coconut shell activated carbon material which is highly pure and has a high surface area.
- the performance and suitability of activated carbon material as an adsorbent in different environments is determined by various physical properties of the material, including the shape and size of the particles, the pore size, the surface area of the material, and so on. These various parameters may be controlled by manipulating the process and conditions by which the activated carbon is produced.
- the larger the surface area of a porous material the greater is the adsorption capacity of the material.
- the surface area of the material may be increased by increasing the number of pores and making the pores smaller, as the size of the pores approaches the size of the target molecule, it is less likely that the target molecules will enter the pores and adsorb to the material. This is particularly true if the material being filtered has a high flow rate relative to the activated carbon material, as is the case in a smoking article.
- porous carbon material has a strong influence on its properties. It is therefore possible to produce carbon particles having a wide range of shapes, sizes, size distributions, pore sizes, pore volumes, pore size distributions and surface areas, each of which influences their
- the attrition rate is also an important variable; low attrition rates are desirable to avoid the generation of dust during high speed filter manufacturing.
- pores in an adsorbent material that are less than 2nm in diameter are called “micropores”, and pores having diameters of between 2nm and 50nm are called “mesopores”. Pores are referred to as “macropores” if their diameter exceeds 50nm. Pores having diameters greater than 500nm do not usually contribute significantly to the adsorbency of porous materials.
- the distribution of pore sizes in a porous carbon material affects the adsorption characteristics, and it has been found that activated carbon material that is rich in micropores and mesopores exhibits excellent filtration of unwanted substances from the vapour phase of tobacco smoke, and an improvement over carbon which includes essentially only micropores.
- a method of preparing porous carbon having mesopores with adsorbent properties suitable for use in smoke filtration comprising: pre-treating a starting material with an alkali solution; and then activating the pre-treated material, wherein the starting material is a carbon precursor or a microporous carbon material.
- the starting material is a carbon precursor
- the alkali solution is preferably removed before the activation step and the pre-treated material is preferably charred prior to activation.
- a porous carbon is provided which is obtained or obtainable by a method according to the first aspect of the invention.
- a filter element is provided, which may be a filter for a smoking article, comprising a porous carbon according to the second aspect of the invention.
- a smoking article is provided, comprising a porous carbon according to the second aspect of the invention.
- Figure 1A shows the N 2 adsorption isotherms of various samples of activated carbon.
- Figure IB shows a bar graph indicating the adsorption properties of the activated carbon samples of Figure 1A.
- Figure 2 shows a table indicating the physical properties of the activated carbon samples of Figures 1A and IB.
- Figure 3 shows a table indicating the physical properties of various activated carbon samples.
- Figure 4 shows the N 2 adsorption isotherms of the activated carbon samples of Figure 3.
- Figure 5 shows a bar graph indicating the adsorption properties of the activated carbon samples of Figure 3.
- Figure 6 shows the N 2 adsorption isotherms of various samples of activated carbon.
- Figure 7 shows a bar graph indicating the adsorption properties of various samples of activated carbon.
- Figure 8 shows the effect of NaOH molarity on the textural properties of various samples of activated carbon.
- the present invention relates to a method involving pre-treating a starting material with an alkali solution prior to an activation step.
- the activation of this pre-treated or doped material encourages the formation of mesopores during the activation step. Without the pre-treatment, the same activation step would result in the formation of micropores only.
- the starting material for the methods of the present invention may be any carbon precursor material.
- This carbon precursor material may be any lignocellulosic material, including, for example, coconut shell, or other naturally-occurring materials including pistachio nut shells, wood chips and bamboo.
- the alkali solution is preferably removed from the pre-treated material, preferably by repeated washing steps, prior to the activation step.
- the starting material for the method of the present invention is a microporous carbon.
- the method introduces mesopores to the already microporous carbon structure.
- the microporous carbon starting material may be conventionally activated carbon, such as microporous activated coconut carbon, or it can be a synthetic microporous carbon.
- the carbon precursor is pre- treated with an alkali solution and the resultant pre-treated material is preferably charred before then being activated.
- Conventional charring methods may be used. No charring step is required where the starting material is a microporous carbon material.
- the alkali may be involved in the dissolution of some of the lignin, hemicellulose and/or other components of the cell structure of a lignocellulosic carbon precursor such as coconut shell.
- Residual sodium ions which remain bound to the precursor may catalyse the carbon gasification. It has been surprisingly found that the production of mesopores in the activated carbon is independent of the alkali concentration over the range stated. Therefore, it is possible to use an alkali solution in the pre-treatment step having a
- Figure 8 shows the effect of NaOH molarity on the textural properties of unwashed carbon, activated at 700°C for 4 hours in steam.
- the graph shows the molarities of NaOH used to pre-treat coconut shell before carbonisation and subsequent activation and the curves indicate the effect on the surface area/porosity of the activated product.
- the alkali solution is an aqueous sodium hydroxide (NaOH) solution.
- NaOH aqueous sodium hydroxide
- NaOH solutions may have a concentration of from about 0.1M, 0.2M, 0.5M, or 0.7M to about 1M, 2M, 3M, 4M, or greater.
- relatively weak solutions for example 1M solutions may be preferred.
- the alkali solutions used may be, for example, Na 2 C0 3 , OH, K 2 C0 3 , KHC0 3 and NH 4 OH. NaOH and Na 2 C0 3 solutions are preferred.
- the pre-treatment with an alkali solution is followed by treatment with solutions of salts that can catalyse carbon gasification, such as iron and copper.
- the carbon precursor may be treated using an iron sulphate solution.
- the treatment with a salt solution is preferably in the form of a separate step to the pre-treatment step.
- the treatment with a salt solution may be carried out before or after the alkali solution pre-treatment step.
- the pre-treatment step may involve contacting the starting material with an alkali solution at room temperatures.
- the alkali solution used in the pre-treatment step of the present invention has a temperature above room temperature.
- the alkali solution used to pre-treat the carbon has a temperature of between 30-60°C, which seems to enhance the formation of mesopores.
- the next step in the methods of the present invention is preferably charring of the pre-treated material.
- Charring or carbonisation
- charring removes hydrogen and oxygen from the solid, so that the remaining product, the char, is composed primarily of carbon.
- Suitable charring or carbonisation methods include those that will be familiar to the skilled person, such as the pit method, the drum method, and destructive distillation.
- the charring step may involve heating the pre-treated carbon to a temperature of at least 500°C and maintaining the carbon at that temperature for a number of hours.
- the charring step involves heating the pre- treated carbon at a rate of 10°C/minute to 600°C under N 2 flowing at a rate of 100 cmVmin.
- the carbon After charring, the carbon is cooled and the carbon surface is preferably
- Activation in the methods of the present invention may be by either physical or chemical means, and conventional activation techniques can be used.
- the material is activated by physical means, and most preferably the material is activated using nitrogen and steam, or alternatively, C0 2 .
- the pre-treated material is activated by reaction with steam under controlled nitrogen atmosphere in a kiln such as a rotary kiln. The temperature is important during the activation process. If the temperature is too low, the reaction becomes slow and is uneconomical. On the other hand, if the temperature is too high, the reaction becomes diffusion controlled and results in loss of the material.
- Activation of the material using nitrogen and steam may be performed at a temperature of between 700°C and 1100°C.
- the activation process is preferably carried out for between 30 minutes and 6 hours.
- the material is activated using nitrogen and steam at about 700°C for 4 hours.
- the material is activated by reaction with carbon dioxide.
- activation of the material may be performed at a temperature of between 700°C and 1100°C, and preferably activation is performed at a temperature of between 800°C and 1000°C.
- the activation process is preferably carried out for between 1 and 6 hours.
- the material is activated by reaction with carbon dioxide at about 800°C for 2-4 hours.
- the surface areas of activated carbon materials are estimated by measuring the variation of the volume of nitrogen adsorbed by the material in relation to the partial pressure of nitrogen at a constant temperature. Analysis of the results by mathematical models originated by Brunauer, Emmett and Teller results in a value known as the BET surface area.
- the BET surface area of the activated carbon materials produced by the method of the invention is at least 500, 550, 600, 650, 700, 750, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800 or at least 1900 m 2 /g.
- Typical values for BET surface area of carbon materials produced by the method of the invention are 850 n 2 /g.
- Porous carbon materials with BET surface areas between 700 m 2 /g and 1300 m 2 / g are preferred.
- the relative volumes of micropores, mesopores and macropores in an activated carbon material can be estimated using well-known nitrogen adsorption and mercury porosimetry techniques.
- Mercury porosimetry can be used to estimate the volume of mesopores and macropores.
- Nitrogen adsorption can be used to estimate the volumes of micropores and mesopores, using the so-called BJH mathematical model.
- BJH so-called BJH mathematical model.
- the method of the invention yields an activated carbon material having a pore structure that includes mesopores and micropores.
- at least 20% but desirably no more than 95% of the pore volume is in mesopores.
- Typical minimum values for the volume of mesopores as a percentage of the combined micropore and mesopore volumes of the carbon materials of the invention are 25%, 35%, or 45%.
- Typical maximum values for such volumes are 95%, 90%, or 85%.
- the mesopore volume of the carbon materials of the invention is in the range of between 55% and 70% of the total pore volume.
- the ratio of mesopores to micropores is preferably between about 1:1 and about 3:1, and is most preferably in the region of about 2:1.
- the porous carbon materials produced by the methods of the present invention preferably have a pore volume (as estimated by nitrogen adsorption) of at least 0.4cm 3 /g, and desirably at least 0.5 cm 3 /g.
- Carbon materials with pore volumes of at least 0.5cm 3 /g are particularly useful as an adsorbent for tobacco smoke.
- Carbon materials according to the invention with pore volumes significantly higher than 2cm 3 /g are low in density and are therefore less easy to handle in cigarette production equipment. Such carbon materials are less favourable for use in cigarettes or smoke filters for that reason.
- the activation step is preferably controlled to ensure that the resultant product contains the desired volume of micropores.
- the product of the present invention has a ratio of at least 1 :2 of micropores to mesopores, which is desirable for good smoke adsorption characteristics.
- the activated carbon produced by the methods of the present invention may be provided in monolithic or particulate form. Particles will preferably have a particle size in the range of between ⁇ and ⁇ . Preferably the mean particle size is between 50 ⁇ and 500 ⁇ , and more preferably between ⁇ and 400 ⁇ . Most preferably, the particles of activated carbon material have a mean size of between
- the inorganic component should generally be washed out at the end of the activation process.
- the coconut shell (100 g) was stirred for 4 hours at 50°C in 300 cm 3 aqueous solutions (usually 1-2M) of: NaOH (4M, 2M, 1M), Na 2 C0 3 , KOH, K 2 C0 3 , and KHC0 3 . The shell was then washed until the liquor was neutral and dried at 100°C overnight.
- coconut shell was heated at 10°C/min to 600°C in flowing N 2 (100 cm 3 /niin). The coconut shell was then held at 600°C for 4 hours. When cool, the charred shell was exposed to a humid N 2 flow (bubbler) to de-activate the carbon surface (necessary because of the high risk of exothermic 0 2 adsorption causing red-heat). 100 g of the shell/impregnated coconut shell yielded 28-29 g char. Measurement of the surface area of one of the chars derived from NaOH-treated shell, using krypton adsorption, gave a value of 0.65 m 2 /g. This indicates that the NaOH treatment alone does not generate significant surface area in the char.
- the standard activation method used involved water (20 cm 3 at 5 cm 3 /hour) introduced using a syringe pump, for 4 hours at 700°C, in N 2 flow of 20 cm 3 /min, with 5 g char.
- Scale-up (5x) activations produced enough activated sample, after sieving to give the correct particle sizes, for smoke testing.
- 100 g raw shell yields approx 28-29 g char, which in turn yields 16-20 g activated carbon.
- a control sample was also prepared from untreated shell, to give the same microporosity, but no mesopores.
- the sample data and isotherms are shown in the graph of Figure 1A.
- the adsorption properties of the samples are shown in the graph of Figure IB. Properties of the samples are set out in the table of Figure 2. There was also good agreement between the scaled-up and normal 5 g scale products with respect to their porosity characteristics.
- samples 20, 21, and 22 Further samples were provided for testing (samples 20, 21, and 22). These were prepared from NaOH-doped shell, steam-activated at 700 °C. One of these samples (sample 22) was washed and re-activated in C0 2 to increase the surface area and microporosity. A purely microporous carbon (sample 24) was also prepared for comparison. All these samples had significantly higher surface areas, micro- and nie sop of o sides than the first samples prepared for testing (see the data in Figure 1A, IB and 2). The sample details are given in the table of Figure 3 and the isotherms are shown in Figure 4.
- Smoke analysis data for these re-activated samples is shown in Figure 5.
- the results indicate that the reduction in toxicants was further increased compared to the first set of samples.
- the washed sample (sample 22) showed significantly improved adsorption characteristics than the other sample across all of the toxicants tested.
- washing the activated carbon in water or dilute acid removes the alkalinity and gives an increase in surface area and/ or porosity, as shown by the data in Tables 3 and 4 below. There appears to be no significant difference in the mass lost using water or acid for post-activation washing.
- the as-received activated carbon (designated JAC) was stirred at 50°C with 2M NaOH solution, and then filtered before drying overnight at 100°C. Samples were then re-activated in steam at 700°C or in C0 2 at 800°C. The large difference in mesopore volume between the steam and C0 2 activated samples shown in Table 5 below may be due to steam washing out the impregnated NaOH during activation.
- the NaOH treatment was also shown to result in mesoporous activated carbons prepared from pistachio nut shells, oak woodchips and bamboo.
- the carbons formed were generally less dense than the coconut carbons.
- the results for pistachio (sample 4, 0.28 cm 3 g _1 micropore volume, 0.35 cm 3 g _1 mesopore volume) suggest that this would be worth further investigation.
- the treatment was also used on activated carbon. For results, see the table in Figure 7.
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- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Carbon And Carbon Compounds (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Cigarettes, Filters, And Manufacturing Of Filters (AREA)
Abstract
Description
Claims
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
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RU2012152543/05A RU2562285C2 (en) | 2010-05-07 | 2011-05-06 | Method for production of filter for tobacco smoke filtering |
KR1020127032008A KR20130062291A (en) | 2010-05-07 | 2011-05-06 | Method of preparing porous carbon |
EP11754714A EP2566812A1 (en) | 2010-05-07 | 2011-05-06 | Method of preparing porous carbon |
JP2013508555A JP2013531596A (en) | 2010-05-07 | 2011-05-06 | Method for producing porous carbon |
KR1020167009156A KR101756223B1 (en) | 2010-05-07 | 2011-05-06 | Method of preparing porous carbon |
CA2797212A CA2797212A1 (en) | 2010-05-07 | 2011-05-06 | Method of preparing porous carbon |
ZA2012/08231A ZA201208231B (en) | 2010-05-07 | 2012-11-01 | Method of preparing porous carbon |
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GBGB1007667.7A GB201007667D0 (en) | 2010-05-07 | 2010-05-07 | Method of preparing porous carbon |
GB1007667.7 | 2010-05-07 |
Publications (1)
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WO2011148156A1 true WO2011148156A1 (en) | 2011-12-01 |
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PCT/GB2011/050882 WO2011148156A1 (en) | 2010-05-07 | 2011-05-06 | Method of preparing porous carbon |
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EP (1) | EP2566812A1 (en) |
JP (1) | JP2013531596A (en) |
KR (2) | KR101756223B1 (en) |
AR (1) | AR081904A1 (en) |
CA (1) | CA2797212A1 (en) |
CL (1) | CL2012003096A1 (en) |
GB (1) | GB201007667D0 (en) |
RU (1) | RU2562285C2 (en) |
WO (1) | WO2011148156A1 (en) |
ZA (1) | ZA201208231B (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102989433A (en) * | 2012-12-11 | 2013-03-27 | 浙江农林大学 | Production method of bamboo powder-amino acid type adsorption material |
CN108455603A (en) * | 2018-05-21 | 2018-08-28 | 四川大学 | Rich in mesoporous biological charcoal and preparation method thereof |
US10411261B2 (en) | 2014-08-08 | 2019-09-10 | Kureha Corporation | Carbonaceous material for non-aqueous electrolyte secondary battery anodes |
US10424790B2 (en) | 2014-08-08 | 2019-09-24 | Kureha Corporation | Carbonaceous material for non-aqueous electrolyte secondary battery anode |
CN110980687A (en) * | 2020-01-07 | 2020-04-10 | 湖北中烟工业有限责任公司 | Method for preparing carbon-based material from waste cut tobacco and application of carbon-based material |
US10797319B2 (en) | 2014-08-08 | 2020-10-06 | Kureha Corporation | Production method for carbonaceous material for non-aqueous electrolyte secondary battery anode, and carbonaceous material for non-aqueous electrolyte secondary battery anode |
CN112794324A (en) * | 2019-11-14 | 2021-05-14 | 华南理工大学 | High-mesoporosity lignin hierarchical pore carbon material and preparation method and application thereof |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5695147B2 (en) * | 2013-09-06 | 2015-04-01 | 東洋炭素株式会社 | Porous carbon, humidity-adsorbing adsorbent, adsorption heat pump, and fuel cell |
KR101943806B1 (en) * | 2015-09-30 | 2019-01-29 | 주식회사 쿠라레 | Carbonaceous material for negative electrode non-aqueous electrolyte secondary battery and manufacturing method thereof |
JP7301294B2 (en) * | 2018-03-02 | 2023-07-03 | 御国色素株式会社 | Porous carbon particles, porous carbon particle dispersion and method for producing the same |
JP7380986B2 (en) * | 2019-03-29 | 2023-11-15 | 群馬県 | Bamboo charcoal and bamboo charcoal manufacturing method |
KR102562397B1 (en) * | 2021-01-13 | 2023-08-01 | 고려대학교 산학협력단 | Highly porous carbon with controlled pore size via hydrothermal carbonization and the method for manufacturing thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3817874A (en) * | 1968-09-18 | 1974-06-18 | Standard Oil Co | Process for increasing the surface area of active carbons |
WO2004047571A2 (en) * | 2002-11-27 | 2004-06-10 | Filtrona International Limited | Tobacco smoke filter |
WO2010103323A1 (en) * | 2009-03-11 | 2010-09-16 | British American Tobacco (Investments) Ltd | Methods for increasing mesopores into microporous carbon |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2064429C1 (en) * | 1992-04-09 | 1996-07-27 | Владимир Васильевич Стрелко | Carbon sorbent and method for its production |
RU2311227C1 (en) * | 2006-02-09 | 2007-11-27 | Институт Катализа Им. Г.К. Борескова Сибирского Отделения Российской Академии Наук | Method of production of the nanostructure carbonic material with the high specific surface and microporosity |
US8198211B2 (en) * | 2006-08-23 | 2012-06-12 | Sulvaris Inc. | Acid-impregnated activated carbon and methods of forming and using the same |
RU2366501C1 (en) * | 2008-04-14 | 2009-09-10 | Институт катализа им. Г.К. Борескова Сибирского отделения Российской академии наук (статус государственного учреждения) | Method for preparation of mesoporous carbon material |
-
2010
- 2010-05-07 GB GBGB1007667.7A patent/GB201007667D0/en not_active Ceased
-
2011
- 2011-05-06 AR ARP110101577A patent/AR081904A1/en unknown
- 2011-05-06 EP EP11754714A patent/EP2566812A1/en not_active Withdrawn
- 2011-05-06 KR KR1020167009156A patent/KR101756223B1/en active IP Right Grant
- 2011-05-06 CA CA2797212A patent/CA2797212A1/en not_active Abandoned
- 2011-05-06 JP JP2013508555A patent/JP2013531596A/en not_active Withdrawn
- 2011-05-06 KR KR1020127032008A patent/KR20130062291A/en active Application Filing
- 2011-05-06 RU RU2012152543/05A patent/RU2562285C2/en not_active IP Right Cessation
- 2011-05-06 WO PCT/GB2011/050882 patent/WO2011148156A1/en active Application Filing
-
2012
- 2012-11-01 ZA ZA2012/08231A patent/ZA201208231B/en unknown
- 2012-11-06 CL CL2012003096A patent/CL2012003096A1/en unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3817874A (en) * | 1968-09-18 | 1974-06-18 | Standard Oil Co | Process for increasing the surface area of active carbons |
WO2004047571A2 (en) * | 2002-11-27 | 2004-06-10 | Filtrona International Limited | Tobacco smoke filter |
WO2010103323A1 (en) * | 2009-03-11 | 2010-09-16 | British American Tobacco (Investments) Ltd | Methods for increasing mesopores into microporous carbon |
Non-Patent Citations (4)
Title |
---|
ADSOLPTIOL1, vol. 14, 2008, pages 335 - 341 |
BRANTON P ET AL: "The effect of carbon pore structure on the adsorption of cigarette smoke vapour phase compounds", CARBON, ELSEVIER, OXFORD, GB, vol. 47, no. 4, 1 April 2009 (2009-04-01), pages 1005 - 1011, XP025940735, ISSN: 0008-6223, [retrieved on 20090211], DOI: 10.1016/J.CARBON.2008.12.003 * |
GONG G-Z ET AL: "Regulation of pore size distribution in coal-based activated carbon", XINXING TAN CAILIAO/ NEW CARBON MATERIALS JUNE 2009 EDITORIAL BOARD OF NEW CARBON MATERIALS CHN, vol. 24, no. 2, June 2009 (2009-06-01), pages 141 - 146, XP002662333 * |
HU Z ET AL: "A simple method for developing mesoporosity in activated carbon", SEPARATION AND PURIFICATION TECHNOLOGY 20030401 ELSEVIER NL, vol. 31, no. 1, 1 April 2003 (2003-04-01), pages 47 - 52, XP002662332, DOI: DOI:10.1016/S1383-5866(02)00148-X * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102989433A (en) * | 2012-12-11 | 2013-03-27 | 浙江农林大学 | Production method of bamboo powder-amino acid type adsorption material |
US10411261B2 (en) | 2014-08-08 | 2019-09-10 | Kureha Corporation | Carbonaceous material for non-aqueous electrolyte secondary battery anodes |
US10424790B2 (en) | 2014-08-08 | 2019-09-24 | Kureha Corporation | Carbonaceous material for non-aqueous electrolyte secondary battery anode |
US10797319B2 (en) | 2014-08-08 | 2020-10-06 | Kureha Corporation | Production method for carbonaceous material for non-aqueous electrolyte secondary battery anode, and carbonaceous material for non-aqueous electrolyte secondary battery anode |
CN108455603A (en) * | 2018-05-21 | 2018-08-28 | 四川大学 | Rich in mesoporous biological charcoal and preparation method thereof |
CN112794324A (en) * | 2019-11-14 | 2021-05-14 | 华南理工大学 | High-mesoporosity lignin hierarchical pore carbon material and preparation method and application thereof |
CN112794324B (en) * | 2019-11-14 | 2022-10-25 | 华南理工大学 | High-mesoporosity lignin hierarchical pore carbon material and preparation method and application thereof |
CN110980687A (en) * | 2020-01-07 | 2020-04-10 | 湖北中烟工业有限责任公司 | Method for preparing carbon-based material from waste cut tobacco and application of carbon-based material |
Also Published As
Publication number | Publication date |
---|---|
GB201007667D0 (en) | 2010-06-23 |
KR20130062291A (en) | 2013-06-12 |
KR101756223B1 (en) | 2017-07-10 |
AR081904A1 (en) | 2012-10-31 |
CL2012003096A1 (en) | 2013-02-15 |
EP2566812A1 (en) | 2013-03-13 |
KR20160044051A (en) | 2016-04-22 |
ZA201208231B (en) | 2015-06-24 |
JP2013531596A (en) | 2013-08-08 |
RU2012152543A (en) | 2014-06-20 |
CA2797212A1 (en) | 2011-12-01 |
RU2562285C2 (en) | 2015-09-10 |
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