====== Active Carbon Absorption of Chemicals ======

The Atmos 500 uses a three stage process to remove airborne contaminants. The first stage filters large particles, the second and activated carbon bed, the third is a HEPA filter (small particles).

Of the three the activated carbon stage is the most important for removing smells and potentially toxic out-gasses caused by the laser cutting process, and is most critical to the operation of the fabrication lab.  

//While most organic compounds will adsorb on activated carbon to some degree, the adsorption process is most effective on higher molecular weight and high boiling point compounds. Compounds having a molecular weight over 50 and a boiling point greater than 50 degrees centigrade are good candidates for adsorption// ((www.carbtrol.com/voc.pdf|Shepard, 2001))


These charts are adapted from [[http://www.lenntech.com/activecarbon-regeneration.htm|More information about the Regeneration of Active Carbon - Lenntech]]

=== Chemicals with very high probability of being adsorbed by active carbon ===
<datatables>
|2,4-D|Deisopropyltatrazine|Linuron|
|Alachlor|Desethylatrazine|Malathion|
|Aldrin|Demeton-O|MCPA|
|Anthracene|Di-n-butylphthalate|Mecoprop|
| [[http://www.lenntech.com/ro/atrazine.htm|Atrazine]]|1,2-Dichlorobenzene|Metazachlor|
|Azinphos-ethyl|1,3-Dichlorobenzene|2-Methyl benzenamine|
|Bentazone|1,4-Dichlorobenzene|Methyl naphthalene|
|Biphenil|2,4-Dichlorocresol|2-Methylbutane|
|2,2-Bipyridine|2,5-Dichlorophenol|Monuron|
|Bis(2-Ethylhexyl)Phthalate|3,6-Dichlorophenol|Napthalene|
|Bromacil|2,4-Dichlorophenoxy|Nitrobenzene|
|Bromodichloromethane|Dieldrin|m-Nitrophenol|
|p-Bromophenol|Diethylphthalate|o-Nitrophenol|
|Butylbenzene|2,4-Dinitrocresol|p-Nitrophenol|
|Calcium Hypochloryte|2,4-Dinitrotoluene|Ozone|
|Carbofuran|2,6-Dinitrotoluene|Parathion|
|Chlorine|Diuron|Pentachlorophenol|
|Chlorine dioxide|Endosulfan|Propazine|
|Chlorobenzene|Endrin|Simazine|
|4-Chloro-2-nitrotoluene|Ethylbenzene|Terbutryn|
|2-Chlorophenol|Hezachlorobenzene|Tetrachloroethylene|
|Chlorotoluene|Hezachlorobutadiene|Triclopyr|
|Chrysene|Hexane|1,3,5-Trimethylbenzene|
|m-Cresol|Isodrin|m-Xylene|
|Cyanazine|Isooctane|o-Xylene|
|Cyclohexane|Isoproturon|p-Xylene|
|DDT|Lindane|2,4-Xylenol|
</datatables>

=== Chemicals with high probability of being adsorbed by active carbon ===


|Aniline|Dibromo-3-chloropropane|1-Pentanol|
|Benzene|Dibromochloromethane|Phenol|
|Benzyl alcohol|1,1-Dichloroethylene|Phenylalanine|
|Benzoic acid|cis-1,2- Dichloroethylene|o-Phthalic acid|
|Bis(2-chloroethyl) ether|trans-1,2- Dichloroethylene|Styrene|
|Bromodichloromethane|1,2-Dichloropropane|1,1,2,2-Tetrachloroethane|
|Bromoform|Ethylene|Toluene|
|Carbon tetrachloride|Hydroquinone|1,1,1-Trichloroethane|
|1-Chloropropane|Methyl Isobutyl Ketone|Trichloroethylene|
|Chlorotoluron|4-Methylbenzenamine|Vinyl acetate|

=== Chemicals with moderate probability of being adsorbed by active carbon ===

**For these chemicals active carbon is only effective in certain cases.
**

|Acetic acid|Dimethoate|Methionine|
|Acrylamide|Ethyl acetate|Methyl-tert-butyl ether|
|Chloroethane|Ethyl ether|Methyl ethyl ketone|
|Chloroform|Freon 11|Pyridine|
|1,1-Dichloroethane|Freon 113|1,1,2-Trichloroethane|
|1,2-Dichloroethane|Freon 12|Vinyl chloride|
|1,3-Dichloropropene|Glyphosate| |
|Dikegulac|Imazypur| |


=== Chemicals for which adsorption with active carbon is unlikely to be effective ===

**However it may be viable in certain cases such as for low flow or concentrations.** 

|Acetone|Methylene chloride|
|Acetonitrile|1-Propanol|
|Acrylonitrile|Propionitrile|
|Dimethylformaldehyde|Propylene|
|1,4-Dioxane|Tetrahydrofuran|
|Isopropyl alcohol|Urea|
|Methyl chloride| |

Factors that influence the performance of active carbon in air

  * Type of compound to be removed: In general compounds with a high molecular weight, lower vapor pressure/higher boiling point and high refractive index are better adsorbed.  
  * Concentration: The higher the concentration, the higher the carbon consumption.
  * Temperature: The lower the temperature, the better the adsorption capacity.
  * Pressure: The higher the pressure, the better the adsorption capacity. 
  * Humidity: The lower the humidity, the better the adsorption capacity.

1) source: Wastewater Engineering; Metcalf & Eddy; third edition; 1991; page 317|

\\ \\ Read more: [[http://www.lenntech.com/library/adsorption/adsorption.htm#ixzz4880i9cJh|http://www.lenntech.com/library/adsorption/adsorption.htm#ixzz4880i9cJh]]