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Activated Carbon

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THE CARBON ENCYCLOPEDIA

    by John A. Weil

    Department of Chemistry

    University of Saskatchewan

    Saskatoon, SK S7N 5C9, Canada

    Email: john.weil@usask.ca

    Assisted by Ms. Petra Dolman

    and Mr. Shawn Verma

    04 Feb 2010

    1

    Table of Contents

Activated Carbon

    Aggregated Diamond Nanorods

    Amorphous Carbon

    Ash

    Binchō-tan

    Bitumen

    Bituminous Coal

    Black Bone

    Black Shale

    Bone Char

    Buckytubes

    Carbon

    Carbon 12

    Carbon 13

    Carbon 14

    Carbon Black

    Carbon Fibers (alias Carbon Filaments)

    Carbon Nanotubes (Also known as Buckytubes)

    Carbon Vapor

    Ceraphite

    Chaoite

    2

Char

    Charcoal

    Coal

    Coal Ash

    Coke

    Diamond

    Diamond-like Carbon Dicarbon

    Endohedral Fullerenes Fly Ash

    Fullerenes

    Fullerite

    Glassy Carbon

    Graphene

    Graphite

    Highly Ordered Pyrolytic Graphite

    Kish Graphite

    Lampblack

    Liquid Carbon

    Lonsdaleite (Lonsdalite) Macerals

    Nanodiamond

    Pitch

    3

    ) 8Prismane (C

    Pyrolytic Carbon (Pyrolytic Graphite) Rhombohedral Graphite

    Slag

    Soot

    Synthetic Diamond

    Tar

    Tricarbon

    Ultra-hard Fullerite

    None-Metal-Doped Fullerenes

Note:

    The @ sign appearing in a name reflects the notion of a small atom or molecule trapped

    inside a shell of atoms.

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    Activated Carbon

    I. Is a term for carbon material mostly derived from charcoal. It denotes a material which has an exceptionally high surface area (just one gram of activated carbon has the surface area of approximately two tennis courts), typically determined by

    nitrogen adsorption, and includes a large amount of microporosity. Sufficient

    activation for useful applications may come solely from the high surface area,

    though often further chemical treatment is used to enhance the absorbing properties

    of the material.

    II. It can generally be produced in two different processes: 1.

    Chemical activation: Mostly acids are mixed with the source material in order to

    cauterize the fine pores. This technique can be problematic because, for example,

    zinc trace residues may remain in the end product.

    2. Steam activation: The carbonised material is mixed with vapours and/or gases at

    high temperature to activate it. The source material can be several carbonic

    materials, e.g. nutshells, wood, coal.

    III. A gram of activated carbon may have a surface area in excess of 400 m?, with 1500 m? being readily achievable. Under an electron microscope, the structure of activated carbon looks a little like ribbons of paper which have been crumpled

    together, intermingled with wood chips. There are a great number of nooks and

    crannies, and many areas where flat surfaces of graphite-like material run parallel to each other, separated by only a few nanometers or so. These micropores provide superb conditions for adsorption to occur, since adsorbing material can interact with

    many surfaces simultaneously. Tests of adsorption behavior are usually done with

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nitrogen gas at 77 K under high vacuum, but in everyday terms activated carbon is

    perfectly capable of producing the equivalent, by adsorption from its environment,

    liquid water from steam at 100 ?C and a pressure of 1/10,000 of an atmosphere. Carbon aerogels, while more expensive, have even higher surface, and find use

    similar to activated carbon in special applications.

    IV. Physically, activated carbon binds materials by Van der Waals force, specifically London dispersion force.

    V. Activated carbon, however, does not bind well to: 1.

    Lithium, strong acids and bases, metals and most inorganic minerals (examples of

    these are sodium, iron, lead, arsenic, fluorine, and boric acid. Activated carbon does adsorb iodine very well and in fact the iodine number, mg/g, (ASTM D28 Standard

    Method test) is used as an indication of total surface area. 2. Alcohol (such as ethanol, methanol, isopropyl alcohol, and glycols). 3. Ammonia

    VI. Activated carbon is used in metal extraction (e.g. gold), water purification (especially in home aquariums), medicine, waste-water treatment, filters in gas and filter masks, filters in compressed air and gas purification, and many other

    applications.

    VII. Carbon absorption has numerous applications in removing pollutants from air or

    water streams both in the field and in industrial processes such as:

    1. Spill cleanup 2. Ground-water remediation

    3. Drinking water filtration

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4. Volatile organic compound capture from painting, dry cleaning and other

    processes

    VIII. Activated carbon is used to treat poisonings and overdoses following oral ingestion. It prevents absorption of the poison by the algastrointestinal tract. In cases of suspected poisoning, medical personnel either administer activated carbon on the

    scene or at a hospital emergency department. Activated carbon has become the treatment of choice for many poisonings, and other decontamination methods such

    as ipecac induced emesis or stomach pumps are now used rarely. The recommended dose in adults is 25 to 100 grams. Pediatric dosages are 10 to 50 g or 0.5 to 1.0

    g/kg.Incorrect application (e.g. into to the lungs) results in pulmonary aspiration

    which can sometimes be fatal if immediate medical treatment is not initiated.For

    pre-hospital use, it comes in plastic tubes or bottles, commonly 12.5 or 25 grams,

    pre-mixed with water. The trade names include InstaChar, SuperChar, Actidose,

    and Liqui-Char, but it is commonly called simply Activated Charcoal.

    IX. Filters with activated carbon are usually used in compressed air and gas purification

    to remove oil vapor, odor, and other hydrocarbons from compressed air and gas.

    The most common designs use a 1-stage or 2-stage filtration principle where

    activated carbon is embedded inside the filter media.

    X. Activated carbon filters can be used to filter vodka of organic impurities. Since the activated carbon does not bind well to alcohol, the percentage of alcohol is not

    significantly affected, but the carbon will bind to and remove many organic

    impurities which can affect color, taste, and odor. Passing an organically impure

    vodka through an activated carbon filter 6-12 times (or through the same number of

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    filters in one pass) will result in vodka with an identical alcohol content and

    significantly increased organic purity, as judged by odor and taste.

    [WWIKIACTIVATED]

    Aggregated Diamond Nanorods (ADNR)

    I. Are an allotrope of carbon, believed to be the least compressible material known to

    humankind, as measured by its isothermal bulk modulus; aggregated diamond nanorods

    have a modulus of 491 gigapascals (GPa), while a conventional diamond has a modulus

    of 442 GPa. ADNRs are 0.3% denser than regular diamond.

    II. The ADNR material is harder than type-IIa diamond and ultra-hard fullerite.

    III. ADNRs are made by compressing allotropic carbon buckyball molecules (generally 60

    carbon atoms per molecule) to a pressure of 20 GPa, while at the same time heating to

    2500 K, using a unique 5000 metric tonne multi-anvil press.

    IV. The resulting substance is a series of interconnected diamond nanorods, with diameters of

    between 5 and 20 nm and lengths of around 1 ?m each. [WWIKIAGGREGATED]

    Amorphous Carbon

    I. Carbon that does not have any crystalline structure. As with all glassy materials, some short-range order can be observed, but there is no long-range pattern of atomic positions.

    II. While entirely amorphous carbon can be made, most of the material described as

    "amorphous" actually contains crystallites of graphite [WGLTRS] or diamond [WIUPAC1],

    with varying amounts of amorphous carbon holding them together, making them technically

    polycrystalline or nanocrystalline materials.

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III. True amorphous carbon has localized π electrons (as opposed to the aromatic π bonds in

    graphite), and its bonds form with lengths and distances that are inconsistent with any other

    allotrope of carbon. It also contains a high concentration of dangling bonds, which cause

    deviations in interatomic spacing (as measured using diffraction) of more than 5%, and

    noticeable variation in bond angle [WIUPAC2].

    IV. Coal and soot are both informally called amorphous carbon.

    Ash

    I. A component in the proximate analysis of biological materials.

    II. Mainly consists of salty non-organic constituents: all the compounds that are not

    considered organic or water.

    III. Includes metal salts which are important for processes requiring cations such as Na

    ++, K,

    2+and Ca.

    IV. Includes trace minerals which are required for unique molecules such as chlorophyll and

    hemoglobin. [WWIKIASH]

Binchō-tan

    I. Is a traditional charcoal of Japan.

    II. It is steamed at high temperatures.

    III. It burns at high temperatures.

    IV. White charcoal.

    V. It is harder than the usual black charcoal, and rings with a metallic sound when struck.

    [WWIKIBINCHO-TAN]

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Bitumen

    I. A category of organic liquids that are highly viscous, black, sticky, and wholly soluble in

    carbon disulfide. II. Asphalt and tar are the most common forms.

    III. In the form of asphalt is obtained by fractional distillation of crude oil; it is the bottom-

    most fraction. IV. In the form of tar is obtained by the destructive distillation of organic matter, usually

    bituminous coal. V. It is primarily used for paving roads, general waterproofing products, including the use of

    bitumen in the production of roofing felt and for sealing flat roofs, as well as the prime

    feed stock for petroleum production from tar sands, currently under development in

    Alberta, Canada. [WWIKIBITUMEN]

Bituminous Coal

    I. Soft coal containing a tar-like substance called bitumen.

    II. Bituminous coal is an organic sedimentary rock formed by diagenetic and

    submetamorphic compression of peat bog material.

    III. Bituminous coal has been compressed and heated so that its primary constituents are the

    macerals vitrinite, exinite, etc.

    IV. The carbon content of bituminous coal is around 60-80%, the rest is comprised of water,

    air, hydrogen, and sulfur componentswhich had not been driven off from the macerals.

    V. The heat content of bituminous coal ranges from 21 to 30 million Btu/ton (24 to 35

    MJ/kg) on a moist mineral-free basis.

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