Activated Charcoal/Carbon

Notes by Newsome.


Scanning electron microscope (SEM) photo of activated charcoal


 

            Left: Standard non-activated charcoal.  Those holes are the pores of the wood.  Notice the smooth surface.

            Right: Activated charcoal.  As you can see the surface is heavily pitted and irregular, increasing surface area.

 


 

Description: Pax HD:Users:danielnewsome:Desktop:Download:charcoal cylinder.jpg

   Activated charcoal (or activated carbon) is charcoal that has been supercharged.  Using chemicals and heat (and sometimes pressure) regular charcoal is sort of roughed up or etched so that it has more surface area.  Probably the simplest way to increase the surface area of charcoal is to simply crush it up.

 

   For example, a cylinder of charcoal, has a surface area of 2¹rh + 2¹r2. [the circumference times the height plus the area of the top and bottom].  If our charcoal cylinder is 10cm tall and has a diameter of 1cm, the total area is about 33cm2.  If we were to slice up this cylinder (like a carrot) into 20 pieces we'd have 40¹r2 instead of just 2¹r2.  The total surface area of this chopped up charcoal would be about 63cm2.  We nearly tripled the surface area. That increase in surface area means that three times as much charcoal is in contact with whatever surrounds it, such as polluted air or water.  Chop up this charcoal even more and you get even more surface area. 

 

"Activating" charcoal goes even further than chopping it up.  It actually pits it... it eats holes in it and roughs up the surface.  [See electron micrographs above.]

 

Depending on a variety of factors (species of carbonized material, added chemicals, methods, and temperatures used for both making the charcoal and the activation processes) the measurement of the surface area of 1 gram of activated charcoal varies significantly.  Most of the data I found ranges from 500-3000 m2 per gram. 

 

Various quantities of a 1500 m2 per gram AC [activated charcoal]

have the following surface areas:

 

AC

in grams

AC in terms of baking measurements

Surface area

in m2

Equivalent familiar areas

1

nearly a 1/2 teaspoon

1500

ca. 6 tennis courts

10

heaping tablespoon

15,000

3 soccer fields

85

3 oz. or about 1/2 cup

127,500

31.5 acres

 


A micrograph of activated charcoal (R 1) under bright field illumination on a light microscope. Notice the fractal-like shape of the particles hinting at their enormous surface area. Each particle in this image, despite being only around 0.1 mm across, can have a surface area of several square centimeters. The entire image covers a region of approximately 1.1 by 0.7 mm, and the full resolution version is at a scale of 6.236 pixels/μm.


   AC removes contaminants that range from around 50 microns to 0.5 microns in size. The smaller the more effective.  It does this by both absorption (internalizing) and adsorption (attachment to the surface).

   Active carbon is  ...

         -very effective in removing at about known 80

               chemicals,

         -effective in another 30 and

         -moderately effective for about 20.

AC doesnÕt remove everything from the tap water, but it removes a lot. 

   According to the EPA activated carbon is the only filter recommended to remove all 32 identified organic contaminants as well as 14 listed pesticides and 12 herbicides.

   Some of the most common concerns about tap water are the by-products from chlorination (VOCs) often referred to as the total trihalomethanes. (TTHMs: chloroform, bromoform, bromodichloromethane, and dibromochloromethane) Activated carbon is very effective in removing these. 

The trihalomethanes are also associated with many of the industrial processes contaminating our air and water.  Chloroform (trichloromethane) is involved in the production of teflon.  Fluoroform (Trifluoromethane) and chlorodifluoromethane (an HCFC) are both used as refrigerants.   


Tri-halo-methane:  CHX3 (where X is any halogen atom)

         1 Carbon + 1 Hydrogen + 3 Halogens.

 

"Tri-halo" refers to 3 halogens. 

"Methane" is the molecular structure of 1 carbon and 4 hydrogens. 

 

"Trihalo-methane" is a methane in which 3 of the 4 hydrogens of standard methane are replaced with 3 halogens ...replaced with a "tri-halo."

 

Note: The halogens are the group of elements on the periodic table [group 17, the column headed by fluorine.] They include fluorine, chlorine, bromine, and iodine.  Halo-gen means "salt-producing" [think halo-genesis[1]].  When halogens react with metals they produce a wide range of salts, including calcium fluoride, sodium chloride (table salt), silver bromide, and potassium iodide.


Oddly enough, I have had trouble finding consistent information on what exactly activated carbon filters out.  In particular, it is frequently claimed that AC filters are effective on chlorine, but then other information rates AC poorly in filtering out chlorine.

 

AC is used extensively in water and air filtration.  It is what is in your Britaª filter and most cartridge respirators.

 

         

 



Substances for which AC filtration is claimed to be effective.

viruses, bacteria, fungi, chemicals

fluoride

iodine

chlorine

sedatives

calcium channel blockers

dapsone

carbamazepine

malaria meds

methylxanthines (stimulants)


Substances for which AC filtration is claimed not to be effective.

ammonia

carbon monoxide

nitrates

fluoride

sodium

various heavy metals

Dissolved solids (minerals, salts, metals). 

Most coliform and bacteria.

Inorganics such as lead, arsenic and asbestos.

Reduces, but doesn't eliminate radioactive nuclides

Lye [Potassium hydroxide (KOH) and Sodium hydroxide (NaOH)]

Iron

Lead (Carbon block filters are effective, not granulated activated carbon)

Reduces arsenic 30%-70%.

Lithium

Alcohols

Petroleum products (paint thinners, etc.).

 


Britaª claims to filter out copper, mercury, and cadmium... and zinc and chlorine

 

I found studies confirming that activated carbon works to capture mercury.


 


List of Chemical, Microbial and Radiological substances filtered by Activated Carbon

https://iaspub.epa.gov/tdb/pages/treatment/treatmentContaminant.do

Name

Synonyms

Contaminant Type

CAS Number

1,2,3-Trichloropropane

1,2,3-TCP, NCI-C60220, TCP, allyl trichloride, glycerol trichlorohydrin, glyceryl trichlorohydrin, trichlorohydrin

Chemical

96-18-4

1,3,5-trinitroperhydro-1,3,5-triazine (RDX)

Cyclonite, Hexogen, RDX, Research Department Explosive, Royal Demolition Explosive, Royal Dutch Explosive

Chemical

82030-42-0

1,4-dioxane

diethylene dioxide, diethylene ether, dioxane, glycol ethylene ether, p-dioxane

Chemical

123-91-1

17a-ethynyl estradiol

EE2

Chemical

57-63-6

4-Nonylphenol

4-Nonylphenol, 4-n-Nonylphenol, NP, Nonylphenol, p-Nonylphenol, para-Nonylphenol

Chemical

104-40-5

Acetochlor

Acenit, Harness, Surpass, Top Hand, Trophy

Chemical

34256-82-1

Acetochlor Degradates

acetochlor ethanesulfonic acid (ESA), acetochlor oxanilic acid (OXA), acetochlor sulfinylacetic acid

Chemical

 

Alachlor

Alanex, Alochlor, Lasso, Lazo, Metachlor, Pillarzo

Chemical

15972-60-8

Aldicarb

Ambush, OMS 771, Temic, Temik, UC 21149 , Unioin Carbide 21149

Chemical

116-06-3

Arsenic

Arsenate, Arsenite, As(3), As(5)

Chemical

7440-38-2

Benzene

Benzol, Coal naphtha, Phene, Polystream, Pyrobenzol

Chemical

71-43-2

Calicivirus

Microbial

 

Carbofuran

Curaterr, Furadan, Yaltox

Chemical

1563-66-2

Chlortetracycline

7-chlorotetracycline, Aureomycin, CLTC, CTC, Chlorotetracyline, Chlortetracyclin

Chemical

57-62-5

Chromium

Chromium (III), Chromium (VI), Cr (III), Cr (VI), Hexavalent Chromium, Trivalent Chromium

Chemical

7440-47-3

Cis-1,2-dichloroethylene

cis-1,2-dichloroethene

Chemical

156-59-2

Cobalt

Co-57, Co-58, Co-59, Co-60

Radiological

7440-48-4

Cryptosporidium

C. parvum, Cryptosporidium parvum

Microbial

 

Dichlorvos

DDVP, Vapona

Chemical

62-73-7

Dicrotophos

Bidrin, Carbicron, Diapadrin, Dicron, Ektafos

Chemical

141-66-2

Ethylene Dibromide

1,2-dibromoethane, EDB, Ethylene bromide, Glycol bromide

Chemical

106-93-4

MTBE

methyl tertiary-butyl ether, methyl-t-butyl ether

Chemical

1634-04-4

Mercury

Hg(0), Hg(2), hydrargyrum, quicksilver

Chemical

7439-97-6

Methomyl

Lannate, Lanox, Methavin, Metofan, Nudrin

Chemical

16752-77-5

Metolachlor

Bicep, Codal, Dual, Milocep

Chemical

51218-45-2

Metolachlor Degradates

Metolachlor ESA, Metolachlor OA, Metolachlor ethane sulfonic acid, Metolachlor oxanilic acid

Chemical

 

Mevinphos

Apavinphos, Duraphos, Fosdrin, Gesfid, Menite, Mevinox, Phosdrin, Phosfene

Chemical

7786-34-7

Microcystins

Microcystin-LR

Chemical

 

Natural Organic Matter

AOC, BDOC, DOC, DOM, NOM, SUVA, TOC, assimilable organic carbon, biodegradable dissolved organic carbon, dissolved organic carbon, dissolved organic matter, fulvic acid, humic acid, specific ultraviolet absorbance, total organic carbon

Chemical

 

Oxamyl

Methyl N',N'-dimethyl-N-[(methylcarbamoyl)oxy]-1-thiooxamimidate, Vydate, Vydate L

Chemical

23135-22-0

Per- and Polyfluoroalkyl Substances

2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate (FRD-902), 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid (FRD-903), GenX, Heptadecafluorononanoic acid, Heptafluorobutyric acid, Nonadecafluorocapric acid, Nonadecafluorodecanoic acid, Pefluorobutane sulfonate, Perfluorobutanoic acid (PFBA), Perfluorobutyl sulfonate (PFBS), Perfluorobutyric acid, Perfluorocapric acid, Perfluorodecanoic acid (PFDA), Perfluorohexanesulfonic acid potassium salt, Perfluorohexyl sulfonate (PFHxS), Perfluorononanoic acid (PFNA), Potassium tridecafluoro-1-hexanesulfonate, Tridecafluorohexane-1-sulfonic acid potassium salt, heptafluoropropyl 1,2,2,2-tetrafluoroethyl ether (E1)

Chemical

 

Perchlorate

Ammonium perchlorate

Chemical

 

Perfluorooctane Sulfonate

1-Octanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro, 1-Octanesulfonic acid, heptadecafluoro-, 1-Perfluorooctanesulfonic acid, Hepatadecafluoro-1-octanesulfonic acid, Perfluoro-n-octanesulfonic acid, Perfluorooctane Sulfonate, Perfluorooctane Sulphonate, Perfluorooctanesulfonic acid, Perfluorooctyl Sulfonate, Perfluorooctylsulfonic acid

Chemical

1763-23-1 (PFOS acid)

Perfluorooctanoic Acid

C8, PFOA, perfluorooctanoate

Chemical

335-67-1

Radium

Ra-226, Ra-228

Radiological

13982-63-3

Saxitoxin

Microbial

 

Simazine and Simazine Degradates

Aquazine, Framed, Gesatop, Premazine, Primatol, Princep, Simadex

Chemical

122-34-9

Strychnine

Certox, Dolco mouse cereal, Kwik-kil, Mole death, Mole-nots, Mouse-rid, Mouse-tox, Pied piper mouse seed, RCRA waste number P108, Rodex, Sanaseed, Strychnidin-10-one, Strychnos, UN 1692

Chemical

57-24-9

Tetrachloroethylene

1,1,2,2-tetrachloroethylene, Ethylene tetrachloride, PCE, PERC, Perchloroethene, Perchloroethylene, Tetrachloroethene

Chemical

127-18-4

Trichloroethylene

TCE, Trichloroethene

Chemical

79-01-6

 


Activated Carbon Adsorption Index Chart

Sentry Air Systems Inc.

https://www.sentryair.com/activated-carbon-adsorption.htm

 

E - Excellent High capacity. Each pound of activated carbon will adsorb an average of 33 - 1/3% of its weight in these compounds.

G - Good. Satisfactory capacity. Each pound of activated carbon will adsorb an average of 16.7% (1/6) of its weight in this compound.

CF - Call Factory for details

 


Compound

Adsorptive

Ability

Acetaldehyde

CF

Acetic Acid

E

Acetic anhydride

E

Acetone (PDF)

G

Acetylene

CF

Acrolem

G

Acrylic Acid

E

Acrylonitrile

E

Alcoholic Beverages

E

Amines

F

Ammonia

CF

Ameyl acetate

E

Amyl alcohol

E

Amyl ether

E

Aniline

E

Asphalt fumes

E

Automobile Exhaust

G

Benzene

E

Body odors

E

Borane

G

Bromine

E

Burned Flesh

E

Burned Food

E

Butadiene

G

Butane

CF

Butanone

E

Butyl acetate

E

Butyl alcohol

E

Butyl cellosolve

E

Butyl chloride

E

Butyl ether

E

Butylene

CF

Butyne

CF

Butyraldehyde

G

Butyric acid

E

Camphor

E

Caprylic acid

E

Carbolic acid

E

Carbon disulfide

E

Carbon dioxide

CF

Carbon monoxide

CF

Carbon tetrachloride

E

Cellosolve

E

Cellosolve acetate

E

Cheese

E

Chorine

G

Chlorobenzene

E

Chlorobutadiene

E

Chloroform

E

Chloronitropropane

E

Chloropicrin

E

Citrus and other fruits

E

Cleaning compounds

E

Coal smoke

G

Creosote

E

Cresol

E

Crotonaldehyde

E

Cychlohexane

E

Cyclohexanol

E

Cyclohexanol

E

Cyclohexene

E

Decane

E

Dibromoethane

E

Dichlorobenzene

E

Dichlorodifluoromethane

G

Dichloroethane

E

Dichloroethylene

E

Dichloroethyl

E

Dichloromonofluormethane

G

Dichloronitroethane

E

Dichloroprpane

E

Dichlorotetrafluoroethane

E

Diesel fumes

E

Diethylamine

G

Diethyl ketone

E

Dimethylaniline

E

Dimethylsulfate

E

Dioxane

E

Diproyl ketone

E

Ethane

CF

Ether (PDF)

G

Ethyl acetate

E

Ethyl acrylate

E

Ethyl alcohol

E

Ethyl amine

G

Ethyl benzene

E

Ethyl bromide

E

Ethyl chloride

G

Ethyl ether (PDF)

G

Ethyl formate

G

Ethyl mercaptan

G

Ethyl silicate

E

Ethylene

CF

Ethylene chlorhydrin

E

Ethylene dichloride

E

Ethylene oxide

G

Essential oils

E

Eucalyptole

E

Fertilizer

E

Film processing odors

G

Fish odors

E

Floral scents

E

Fluorotrichloromethane

G

Formaldehyde (PDF)

G

Formic acid

G

Gangrene

E

Garlic

E

Gasoline

E

Heptane

E

Heptylene

E

Hexane

G

Hexylene

G

Hexyne

G

Hydrogen

CF

Hydrogen bromide

G

Hydrogen chloride

CF

Hydrogen cyanide

G

Hydrogen fluoride

CF

Hydrogen iodide

G

Hydrogen selenide

CF

Hydrogen sulfide

G

Incensen

E

Indole

E

Iodine

E

Iodoform

E

Irritants

E

Isophorone

E

Isoprene

G

Isopropyl acetate

E

Isopropyl aclcohol (PDF)

E

Isopropyl ether

E

Kerosene

E

Kitchen odors

E

Lactic acid

E

Menthol

E

Mercaptans

E

Methane

CF

Methil acetate

G

Menthyl acrylate

E

Methyl alcohol

G

Methyl bromide

G

Methyl butyl ketone

E

Methyl cellosolve

E

Methyl cellosolve acetate

E

Methyl chloride

G

Methyl chloroform

E

Methyl ether

G

Methyl ethyl ketone (PDF)

E

Methyl formate

G

Methyl isobutyl ketone

E

Methyl mercaptan

E

Methylcyclohexane

E

Methylcyclohexanol

E

Methylcyclohexaone

E

Methylene chloride (PDF)

E

Monochlorobenzene

CF

Monofluorotri cloromethane

E

Naphtha

E

Naphthziene

E

Nitric acid

G

Nitro benzenes

E

Nitroethane

E

Nitrogen dioxide

CF

Nitroglycerine

E

Nitromethane

E

Nitropropane

E

Nitrotoluene

E

Nonane

E

Octalene

E

Octane

E

Onions

E

Organic Chemicals

E

Ozone

E

Packing house odors

E

Paint & redecorating odors

E

Palmitic Acid

E

Paradichlorbenzine

E

Pantane

G

Pentanone

E

Pentylene

G

Pentyne

G

Perchloroethylene

E

Perfumes, cosmetics

E

Phenol

E

Phosgene

G

Pitch

E

Poison gases

G

Pollen

G

Popcorn and candy

E

Poultry odors

E

Propane

CF

Propionaldehyde

G

Propionic acid

E

Propyl acetate

E

Propyl alcohol

E

Propyl chloride

E

Propyl ether

E

Propyl mercaptan

E

Propylene

CF

Propyne

CF

Putrefying substances

G

Putrescine

E

Pyridine

E

Resins

E

Rubber

E

Sauerkraut

E

Sewer odors

E

Skalote

E

Slughtering odors

G

Smog

E

Sour milks

E

Stoddard sovent

E

Styrene monomer

E

Sulfur dioxide

CF

Sulfur trioxide

G

Sulfuric acid

E

Tetrachloroethane

E

Tetrachloroethylene

E

Tobacco smoke odor

E

Toilet odors

E

Toluene (PDF)

E

Toluidine

E

Trichlorethylene

E

Trichloroethane

E

Turpentine

E

Urea

CF

Uric acid

E

Valeric acid

E

Valericaldehyde

E

Varnish fumes

E

Xylene (PDF)

E



 



[1] Like hydrogen (water producing), oxygen (acid producing), nitrogen (saltpeter/nitre producing), estrogen (estrus/heat producing), mutagen (mutation/change producing), pathogen (suffering producing), and pyrogen (fire/fever producing).