THE AFFINITY OF ACTIVATED CARBON IN RELATION TO VARIOUS CONTAMINATING COMPONENTS.

General

The adsorption capacity of activated carbons is influenced by a number of process conditions, e.g.

  • type(s) and concentration(s) of component(s)
  • the humidity and temperature of the gasflow
  • velocity and contacttime
  • poresize and poredistribution of the activated carbon used.

Below we present a survey of components which are in principle suitable for removal using activated carbon. The qualifications given are based on optimum process conditions, where activated carbon can be used at equilibrium (full) adsorption capacity. In practice however, the conditions are never at such an optimum level, so the effective adsorption capacity will usually be somewhat lower.

Qualifications

The affinity indexation is expressed as (1), (2), (3) and (4), where :

  1. high adsorption capacity, i.e.
    1 kg carbon can take 20-50 w/w%. Average 35 w/w%.

  2. satisfactory adsorption capacity, i.e.
    1 kg carbon can take 10-25 w/w%. Average 17 w/w%.

  3. moderate adsorption capacity, i.e.
    1 kg carbon can take 5-10 w/w%. Average 7 w/w%.

  4. low adsorption capacity, i.e.
    - basic activated carbon will not be very (cost)effective
    - impregnated activated carbon may improve results.

Gases (such as mercury fumes, ammonia, hydrogen sulphides, etc.) that can effectively be removed using different types of impregnated carbons are marked with (*). Where possible, the chemical formula is given. In a few cases, more than one name is mentioned for only one chemical component.

 

Acetaldehyde

C2H4O

3

Acetic acid (vinegar)

C2H4O2

1

Acetic anhydride

C4H6O3

1

Acetone

C3H6O

2

Acetonenitrile

C3H3NO

3

Acetylene

C2H2

3

Acrolein

C3H4O

2

Acrylic acid (acrylate)

C3H4O2

1

Acrylonitrile (vinylcyanide)

C3H3N

1

Adhesives

 

1

Allyl chloride

C3H5Cl

1

Amines *

 

3

Ammonia *

NH3

4

Amyl acetate (isomers)

C7H14O2

1

Amyl alcohol (pentanol)

C5H12O

1

Amyl ether

C10H22O

1

Anniline

 

1

Antiseptics

 

1

Asphalt fumes

 

1

Benzene

C6H6

1

Blood odour

 

2

Body odour

 

1

Bromine

Br2

1

Butadiene

C4H6

2

Butane

C4H10

3

Butanone (MEK)

C4H8O

1

Butyl acetate

C6H12O2

1

Butyl alcohol (butanol)

C4H10O

1

Butyl cellosolve

C6H14O2

1

Butyl chloride

C14H9Cl

1

Butyl ether

C8H18O

1

Butylene/butane

C4H8

3

Butyraldehyde

C4H8O

1

Butyric acid

C4H8O2

1

Camphor

C10H16O

1

Caprylic acid

C8H16O2

1

Carbolic acid (phenol)

C6H6O

1

Carbon dioxide

CO2

3

Carbon disulphide

CS2

1

Carbon monoxide *

CO

4

Carbon tetrachloride

CCl4

1

Cellosolve acetate

C6H12O3

1

Chlorine

Cl2

2

Chlorobenzene (phenylchloride)

C6H5Cl

1

Chlorobutadiene (chloroprene)

C4H5Cl

1

Chloroform (trichloromethane)

CHCl3

1

Chloromethane (methylchloride)

CH3Cl

2

Chloronitropropane

C3H6ClNO2

1

Chloropicrine

CCl3NO2

1

Cigarette odour

 

1

Combustion fumes

 

2

Corrosive gases *

 

3

Creosote

 

1

Cresol

C21H24O3

1

Cyclohexane

C6H12

1

Cyclohexanol

C6H12O

1

Cyclohexanone

C6H10O

1

Cyclohexene

C6H10

1

Decane

C10H22

1

Detergents

 

1

Dibromoethane

C2H4Br

1

Dichloro ethyl ether

C4H8Cl2O

1

Dichlorobenzene

C6H4Cl2

1

Dichlorodifluoro-methane

CCl2F2

1

Dichloroethane

C2H4Cl2

1

Dichloroethylene

C2H2Cl2

1

Dichloromonofluoro-methane

CHCl2F

2

Dichloronitroethane

C2H3Cl2NO2

1

Dichloropropane

C3H6Cl2

1

Dichlorotetrafluoro-ethane

C2Cl2F4

1

Diesel fumes

 

1

Diethylketone

C5H10O

1

Dimethyl aniline

C8H11N

1

Dimethyl sulphate

C2H6O4S

1

Dimethyl sulphide*

C2H6S

1

Dioxane

C4H8O2

1

Dipropyl ketone

C7H14O

1

Epichlorohydrin

C3H5ClO

1

Ethane *

C2H6

4

Ether

C4H10O

1

Ethyl acetate

C4H8O2

1

Ethyl acrylate

C5H8O2

1

Ethyl alcohol

C2H6O

2

Ethyl benzene

C8H10

1

Ethyl bromide

C2H5Br

1

Ethyl chloride

C2H5Cl

2

Ethyl formate

C3H6O2

2

Ethyl mercaptan*

C2H6S

1

Ethyl silicate

C8H20O4Si

1

Ethylene *

C2H4

4

Ethylene chlorohydrin

C2H5ClO

1

Ethylene dichloride

C2H4Cl2

1

Ethylene oxide

C2H4O

3

Fish/food/fruit odours

 

1

Formic acid *

CH2O2

3

Freon 11/12/113

 

1

Gasoline

 

1

Heptane

C7H16

1

Heptylene

C7H14

1

Hexanol

C6H14O

1

Hexanone (MIBK)

C6H12O

1

Hydrogen *

H2

4

Hydrogen bromide *

BrH

3

Hydrogen chloride *

ClH

3

Hydrogen cyanide *

HCN

4

Hydrogen fluoride *

FH

3

Hydrogen selenide *

H2Se

3

Hydrogen sulphide *

H2S

2

Iodine

I2

1

Iodoform

CHI3

1

Isopropyl acetate

C5H10O2

1

Isopropyl alcohol propanol

C3H8O

1

Isopropyl chloride

C3H7Cl

1

Isopropyl ether

C6H14O

1

Kerosine

 

1

Kitchen odours

 

1

Krypton delay

 

1

Lactic acid

C3H6O3

1

Lysol

 

1

Menthol

C10H20O

1

Mercaptans (large molecules)*

C2H6S

1

Mercury fumes *

Hg

4

Mesityl oxide

C6H10O

1

Methane *

CH4

4

Methyl acetate

C3H6O2

2

Methyl acrylate

C4H6O2

1

Methyl alcohol methanol

CH4O

2

Methyl bromide

CH3Br

2

Methyl butyl ketone hexanone

C6H12O

1

Methyl cellosolve (acetate)

C3H8O2

1

Methyl chloride

CH3Cl

2

Methyl chloroform

C2H3Cl3

1

Methyl cyclohexane

C7H14

1

Methyl cyclohexanone

C7H12O

1

Methyl ether

C2H6O

2

Methyl ethyl ketone (MEK)

C4H8O

1

Methyl formate

C4H4O2

2

Methyl glycol

C3H8O2

1

Methyl isobutyl ketone (MIBK)

C6H12O

1

Methyl mercaptan *

CH4S

3

Methyl metacrylate ester

 

1

Methylene chloride

CH2Cl2

1

Monochlorobenzene phenylchloride

C6H5Cl

1

Monofluortrichloro-methane

CCl3F

1

Naphta(lene)

C10H8

1

Nicotine

C10H14N2

1

Nitric acid

HNO3

3

Nitrobenzene

C6H5NO2

1

Nitroethane

C2H5NO2

1

Nitrogen dioxide

NO2

3

Nitroglycerine

C3H5N3O9

1

Nitromethane

CH3NO2

2

Nitropropane

C3H7NO2

1

Nitrotoluene

C7H7NO2

1

Octane

C8H18

1

Octene

C8H16

1

Oil fumes

 

1

Ozone

O3

1

Palmitic acid

C16H32O2

1

Para-dichloro benzene

C6H4Cl2

2

Pentane

C5H12

2

Pentanone

C9H18O

1

Pentene

C5H10

2

Pentyne

C5H8

2

Perchloroethylene Tetrachloroethylene

C2Cl4

1

Pesticides

 

1

Phenol

C6H6O

1

Phosgene

CCl2O

2

Poisonous gases*

 

1

Propane

C3H8

3

Propionic acid

C3H6O2

2

Propyl acetate

C5H10O2

1

Propyl alcohol propanol

C3H8O

1

Propyl aldehyde

C3H6O

2

Propyl chloride

C3H7Cl

1

Propyl ether

C6H14O

1

Propyl mercaptan

C3H8S

1

Sewer odours *

 

2

Slaughter odours

 

2

Styrene monomer

C8H8

1

Sulphur dioxide *

SO2

3

Sulphur trioxide *

SO3

3

Sulphuric acid

H2SO4

3

Tar fumes

 

1

Tetrachloroethane

C2H2Cl4

1

Tetrachloroethylene Perchloroethylene

C2Cl4

1

Tetrahydrofuran

C4H8O

1

Thiophene

C4H4S

1

Toluene

C7H8

1

Toluene di-isocyanate

C9H6N2O

1

Trichloroethane

C2H3Cl3

1

Trichloroethylene

C2HCl3

1

Turpentine

 

1

Urea

CH4N2O

1

Uric acid

C5H4N4O3

1

Valeric acid

C5H10O2

1

Valeric aldehyde

C5H10O

1

Vinegar Acetic acid

C2H4O2

1

Vinyl acetate

C4H6O2

1

Vinyl chloride monomer (VCM)

C2H3Cl

1

Xenon delay

 

1

Xylene

C24H30

1


REMARK:

Unstable components such as ketones should preferably not be treated when present in the gasflow at high concentrations. They have the ability to oxidize, polymerize or may form peroxides. These chemical reactions are exothermic and may cause so-called 'hot spots' at random places in the carbonbed. Safety precautions such as CO/CO2 monitoring, inert gas blanketing and/or water flooding should be taken.

Under circumstances, pre-wetting of the activated carbon may be considered.