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Activated carbon

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  • sonum norbu
    A question for the chemists out there. How is activated carbon activated ? What does activated mean? Could one use charcoal from a fire burning Box
    Message 1 of 4 , Oct 2, 2005
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      A question for the chemists out there. How is activated carbon "activated"? What does "activated" mean? Could one use charcoal from a fire burning Box (australian hardwood) and crushing the hell out of it? blanikdog




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    • Harry
      ... carbon activated ? What does activated mean? Could one use charcoal from a fire burning Box (australian hardwood) and crushing the hell out of it?
      Message 2 of 4 , Oct 2, 2005
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        --- In new_distillers@yahoogroups.com, "sonum norbu" <blanik@o...>
        wrote:
        > A question for the chemists out there. How is activated
        carbon "activated"? What does "activated" mean? Could one use
        charcoal from a fire burning Box (australian hardwood) and crushing
        the hell out of it? blanikdog



        Charcoal is carbon. Activated charcoal is charcoal that has been
        treated with oxygen to open up millions of tiny pores between the
        carbon atoms.

        According to Encylopedia Britannica...

        The use of special manufacturing techniques results in highly porous
        charcoals that have surface areas of 300-2,000 square metres per
        gram. These so-called active, or activated, charcoals are widely
        used to adsorb odorous or coloured substances from gases or liquids.

        The word adsorb is important here. When a material adsorbs
        something, it attaches to it by chemical attraction. The huge
        surface area of activated charcoal gives it countless bonding sites.
        When certain chemicals pass next to the carbon surface, they attach
        to the surface and are trapped. Activated charcoal is good at
        trapping other carbon-based impurities ("organic" chemicals), as
        well as things like chlorine.

        Many other chemicals are not attracted to carbon at all -- sodium,
        nitrates, etc. -- so they pass right through. This means that an
        activated charcoal filter will remove certain impurities while
        ignoring others. It also means that, once all of the bonding sites
        are filled, an activated charcoal filter stops working. At that
        point you must replace the filter.

        -----------------------------------------------


        Activated Carbon: How and Why It Works



        Adsorption vs. Absorption

        Removing gases and vapors involves capturing particles .01 microns
        and smaller. A micron is 1/25,400 of an inch. Particulate filters,
        like HEPA filters are effective into the .3 micron range. They can
        not and do not remove material that is as small as a gas. Activated
        carbon uses the process of ADSORPTION to remove gases and vapors
        from the air stream. The question often asked is what is the
        difference between ADSORPTION and ABSORPTION.



        ADSORPTION is the physical attraction and adherence of gas or liquid
        (vapor) molecules to the surface of a solid. Gas and vapor molecules
        are adsorbed by the solid activated carbon.



        ABSORPTION is the dissolving and even mixing of a substance in a
        liquid. Think of sugar being mixed into coffee. In an industrial
        application the gas is absorbed by a "scrubbing" liquid.



        Why is activated carbon a good adsorbent?

        Activated carbon is a unique material. No other material natural or
        man made has all these properties and abilities:



        1. It has the ability to adsorb some of almost any vapor.

        2. It has a large capacity for organic molecules, especially
        solvents. 3. It adsorbs and retains a wide variety of chemicals at
        the same time. 4. It works well under a wide range of temperatures
        and humidity levels. 5. It is inert and safe to handle and use. 6.
        It is readily available and affordable.



        What is activated carbon?

        It is a material that has been treated, or activated, to increase
        the internal surface area to the range of 950 to 1150 square meters
        per gram. The internal surface area is what holds the adsorbed gases
        and vapors. It is where the "work" of the filter is done. The term
        activated charcoal is often used interchangeably with activated
        carbon. They refer to the same material.



        How does it work?

        The Non-technical Explanation: It starts with the gas molecule
        coming in contact with the surface of an activated carbon particle.
        The gas molecule comes to rest in a large surface pore on the
        particle. Unbalanced forces on and within the carbon particle cause
        the gas molecule to move down into the smaller pores of the carbon
        particle where it will stop and be held in place. At some point the
        gas molecule will condense and become a liquid particle, trapped
        inside the carbon.



        The Technical Explanation: The adsorbate (gas) diffuses through
        the surface film of macropore structure (activated carbon). Van der
        Walls' forces cause the gas to migrate into the micropore structure,
        condensing during this movement. It stops when either the forces
        become balanced or it is physically blocked.



        What types of gases and vapors are adsorbed?

        Activated carbon is the universal adsorbent and will adsorb "some
        of almost any vapor". Below is a partial list of gases that are
        removed by activated carbon filter systems.



        : Organic Compounds: Acids, Alcohols, Aldehydes

        : Chlorinated Hydrocarbons: Esters, Ethers, Ketones, Mercaptans,
        Amines

        : Inorganic Compounds: Halogen Acids, Halogens, Sulphuric Acid,
        Sulphur Dioxide, Phosgene

        : Odors: Human, Animals, Food, Waste Processes, Cooking



        Source:

        James W. Kasmark Jr.; B.S. Mechanical Engineering; President D-
        MARK; "Activated Carbon" Why is it used?, ©2000, D-Mark Inc.



        Slainte!
        regards Harry
      • sonum norbu
        Thank you Harry. You answered everything I wanted to know in words suitable for a poor Archaeology major, not a chemist :)) What amazing stuff it is!!! Thanks
        Message 3 of 4 , Oct 2, 2005
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          Thank you Harry. You answered everything I wanted to know in words
          suitable for a poor Archaeology major, not a chemist :)) What amazing
          stuff it is!!! Thanks again..... blanikdog.

          ----- Original Message -----
          From: Harry
          To: new_distillers@yahoogroups.com
          Subject: [new_distillers] Re: Activated carbon
          Date: Mon, 03 Oct 2005 04:37:36 -0000

          --- In new_distillers@yahoogroups.com, "sonum norbu" <blanik@o...>
          wrote:
          > A question for the chemists out there. How is activated
          carbon "activated"? What does "activated" mean? Could one use
          charcoal from a fire burning Box (australian hardwood) and crushing
          the hell out of it? blanikdog



          Charcoal is carbon. Activated charcoal is charcoal that has been
          treated with oxygen to open up millions of tiny pores between the
          carbon atoms.

          According to Encylopedia Britannica...

          The use of special manufacturing techniques results in highly porous
          charcoals that have surface areas of 300-2,000 square metres per
          gram. These so-called active, or activated, charcoals are widely
          used to adsorb odorous or coloured substances from gases or liquids.

          The word adsorb is important here. When a material adsorbs
          something, it attaches to it by chemical attraction. The huge
          surface area of activated charcoal gives it countless bonding sites.
          When certain chemicals pass next to the carbon surface, they attach
          to the surface and are trapped. Activated charcoal is good at
          trapping other carbon-based impurities ("organic" chemicals), as
          well as things like chlorine.

          Many other chemicals are not attracted to carbon at all -- sodium,
          nitrates, etc. -- so they pass right through. This means that an
          activated charcoal filter will remove certain impurities while
          ignoring others. It also means that, once all of the bonding sites
          are filled, an activated charcoal filter stops working. At that
          point you must replace the filter.

          -----------------------------------------------


          Activated Carbon: How and Why It Works



          Adsorption vs. Absorption

          Removing gases and vapors involves capturing particles .01 microns
          and smaller. A micron is 1/25,400 of an inch. Particulate filters,
          like HEPA filters are effective into the .3 micron range. They can
          not and do not remove material that is as small as a gas. Activated
          carbon uses the process of ADSORPTION to remove gases and vapors
          from the air stream. The question often asked is what is the
          difference between ADSORPTION and ABSORPTION.



          ADSORPTION is the physical attraction and adherence of gas or liquid
          (vapor) molecules to the surface of a solid. Gas and vapor molecules
          are adsorbed by the solid activated carbon.



          ABSORPTION is the dissolving and even mixing of a substance in a
          liquid. Think of sugar being mixed into coffee. In an industrial
          application the gas is absorbed by a "scrubbing" liquid.



          Why is activated carbon a good adsorbent?

          Activated carbon is a unique material. No other material natural or
          man made has all these properties and abilities:



          1. It has the ability to adsorb some of almost any vapor.

          2. It has a large capacity for organic molecules, especially
          solvents. 3. It adsorbs and retains a wide variety of chemicals at
          the same time. 4. It works well under a wide range of temperatures
          and humidity levels. 5. It is inert and safe to handle and use. 6.
          It is readily available and affordable.



          What is activated carbon?

          It is a material that has been treated, or activated, to increase
          the internal surface area to the range of 950 to 1150 square meters
          per gram. The internal surface area is what holds the adsorbed gases
          and vapors. It is where the "work" of the filter is done. The term
          activated charcoal is often used interchangeably with activated
          carbon. They refer to the same material.



          How does it work?

          The Non-technical Explanation: It starts with the gas molecule
          coming in contact with the surface of an activated carbon particle.
          The gas molecule comes to rest in a large surface pore on the
          particle. Unbalanced forces on and within the carbon particle cause
          the gas molecule to move down into the smaller pores of the carbon
          particle where it will stop and be held in place. At some point the
          gas molecule will condense and become a liquid particle, trapped
          inside the carbon.



          The Technical Explanation: The adsorbate (gas) diffuses through
          the surface film of macropore structure (activated carbon). Van der
          Walls' forces cause the gas to migrate into the micropore structure,
          condensing during this movement. It stops when either the forces
          become balanced or it is physically blocked.



          What types of gases and vapors are adsorbed?

          Activated carbon is the universal adsorbent and will adsorb "some
          of almost any vapor". Below is a partial list of gases that are
          removed by activated carbon filter systems.



          : Organic Compounds: Acids, Alcohols, Aldehydes

          : Chlorinated Hydrocarbons: Esters, Ethers, Ketones, Mercaptans,
          Amines

          : Inorganic Compounds: Halogen Acids, Halogens, Sulphuric Acid,
          Sulphur Dioxide, Phosgene

          : Odors: Human, Animals, Food, Waste Processes, Cooking



          Source:

          James W. Kasmark Jr.; B.S. Mechanical Engineering; President D-
          MARK; "Activated Carbon" Why is it used?, ©2000, D-Mark Inc.



          Slainte!
          regards Harry







          New Distillers group archives are at http://archive.nnytech.net/
          FAQ and other information available at http://homedistiller.org




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          "Most of the troubles of the world are caused by human beings". (Shakyamuni Buddha)

          SOARING, SAILING AND SKYDIVING web page
          http://www.angelfire.com/fl2/cloudbase/
          IRC server tessnet.cx

          --
          _______________________________________________
          Surf the Web in a faster, safer and easier way:
          Download Opera 8 at http://www.opera.com

          Powered by Outblaze


          [Non-text portions of this message have been removed]
        • Harry
          ... You can download a free 28 page pdf from Gert Strand about activated carbon and details of how it s made and used. Apart from the glaring mistake of
          Message 4 of 4 , Oct 3, 2005
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            --- In new_distillers@yahoogroups.com, "sonum norbu" <blanik@o...>
            wrote:
            > Thank you Harry. You answered everything I wanted to know in words
            > suitable for a poor Archaeology major, not a chemist :)) What amazing
            > stuff it is!!! Thanks again..... blanikdog.



            You can download a free 28 page pdf from Gert Strand about activated
            carbon and details of how it's made and used. Apart from the glaring
            mistake of ADsorption vs ABsorption, the booklet is an interesting
            read.
            http://www.home-distillation.com/freebook.html


            Slainte!
            regards Harry
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