Sciencemadness Discussion Board

Activated Carbon Filter For Organic Vapors

organicchemist25 - 24-2-2014 at 12:07

I was wondering, is it ok to exhaust most organic vapors through an activated carbon filter? Any particular dangers or certain solvents that should not be ran through an activated carbon filter? Or are there any better suggestions as to what to use instead.

I think it should be moderately safe, but I want to see if anyone thinks or knows different.

thesmug - 24-2-2014 at 12:49

Quote: Originally posted by organicchemist25  
I was wondering, is it ok to exhaust most organic vapors through an activated carbon filter? Any particular dangers or certain solvents that should not be ran through an activated carbon filter? Or are there any better suggestions as to what to use instead.

I think it should be moderately safe, but I want to see if anyone thinks or knows different.


This should answer your questions:
http://en.wikipedia.org/wiki/Activated_carbon#Examples_of_ad...

Dr.Bob - 25-2-2014 at 13:49

I can't think of any normal solvents that would be a problem. Some more unusual acids, like acid oxidants (eg, perchloric acid) can be absorbed on organics with the danger of fires/explosions, but few people will be working with that at home, I hope.

But we have used them before. The biggest challenge for a hood type filter system is that if you have enough flow to be safe, it is hard to have enough residence time for the chemicals to adsorb on the the charcoal. Most systems that I have used are only really meant to remove the particles, polar materails, and higher bp solvents-low bp solvents don't get captured well. Many of the systems warned that they might not handle those well.

Electra - 25-2-2014 at 15:32

Quote: Originally posted by Dr.Bob  
I can't think of any normal solvents that would be a problem. Some more unusual acids, like acid oxidants (eg, perchloric acid) can be absorbed on organics with the danger of fires/explosions, but few people will be working with that at home, I hope.

But we have used them before. The biggest challenge for a hood type filter system is that if you have enough flow to be safe, it is hard to have enough residence time for the chemicals to adsorb on the the charcoal. Most systems that I have used are only really meant to remove the particles, polar materails, and higher bp solvents-low bp solvents don't get captured well. Many of the systems warned that they might not handle those well.


What would you suggest? I made a thread about a similar concern and was told that for most organic reactions an activated carbon filter would be most suited.

zig - 25-2-2014 at 20:43

Well are ya working with anything that falls outside the category, "most organics"? I mean porque no los dos? If you have any specific in mind you could find the corresponding filter and run it in series with an activated carbon filter..

[Edited on 26-2-2014 by zig]

Electra - 25-2-2014 at 20:54

Quote: Originally posted by zig  
Well are ya working with anything that falls outside the category, "most organics"? I mean porque no los dos? If you have any specific in mind you could find the corresponding filter and run it in series with an activated carbon filter..

[Edited on 26-2-2014 by zig]


I would say 90% of the fumes that I have ever had problems with have been acid fumes. Working with sulfuric acid commonly... this can be a problem, as well as with other acids. Breathing them in is not fun. Not fun at all. From what I gather, carbon filters do nothing to absorb them. While general odors and possible reaction by-product gasses may generally occur, and be filtered by the activated carbon.... acids glide right on through the filter, at least, according to wiki and many other sources.

[Edited on 26-2-2014 by Electra]

zig - 25-2-2014 at 21:28

Quote: Originally posted by Electra  

I would say 90% of the fumes that I have ever had problems with have been acid fumes. Working with sulfuric acid commonly... this can be a problem, as well as with other acids. Breathing them in is not fun. Not fun at all. From what I gather, carbon filters do nothing to absorb them. While general odors and possible reaction by-product gasses may generally occur, and be filtered by the activated carbon.... acids glide right on through the filter, at least, according to wiki and many other sources.

[Edited on 26-2-2014 by Electra]


"Not fun at all" haha no, its not. I'd say it approaches the antithesis of fun. HCl is my particular personal hell.
If your system allows for it you could bubble the rxn exhaust through a dilute base soln to neutralize, but that can be a pain in the ass to rig up in many cases.

http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/sulfu... says:

Respiratory Protection: Up to 15 mg/m3: wear a approved air-purifying respirator with acid gas cartridge in combination with an N100, R100, or P100 filter. Or, wear a NIOSH approved self-contained breathing apparatus (SCBA) or supplied air respirator.

Maybe look into these so called "acid gas cartridge", see what their guts are generally made of.

Dr.Bob - 26-2-2014 at 12:27

For acids, a simple paste of NaHCO3 or Na2CO3 might work. But they work best when wet or if the exhaust is slight damp. But they would work some even if dry. CaOH or CaCO3 also work, and are used for industrial scrubbers for acid.