Sciencemadness Discussion Board

Charcoal as dessicant?

triplepoint - 30-8-2012 at 08:59

I just received a package that included two large dessicant bags. They are Unit Paks from Desiccare. They are 8 unit milspec, according to the labelling, which basically means that each one is rated to absorb 8 oz of water. My first thought was what I would do with that much silica. My 2nd thought was to look up the composition before I opened anything. According to the company's website, of is either silica, clay or perlite. The site said that charcoal, while not a dessicant, may be mixed in for odor control. I opened a bag and, you guessed it from the title of the post, it was 100% charcoal. Is charcoal a dessicant? Was this a manufacturing mix-up or what? No harm was done, but there is clearly something wrong with this picture.

Hexavalent - 30-8-2012 at 11:17

Are you absolutely certain that it was actually just charcoal; I have used charcoal previously with other stuff added and it was still very dark.

bbartlog - 30-8-2012 at 12:58

So, how did you verify that it was 100% charcoal? I would expect mixed perlite and charcoal to be really hard to tell apart from just charcoal.

triplepoint - 30-8-2012 at 16:44

I certainly could be wrong. It is uniformly composed of jet (or coal) black irregularly shaped granules. I examined some of the pieces closely with my naked eye - not microscope. They appear to be charcoal. I broke open some pieces and they were all uniformly jet black inside. It is not just staining from proximity to charcoal. Of course zeolite (not perlite as I said earlier) could look similar. I am a beginner in lab procedures, but I am looking for a qualitative test that I could use to confirm or exclude the presence of zeolite. I have found this one but I do not think I can recreate it with my limited knowledge and setup. I'll keep looking.

http://www.minsocam.org/ammin/AM58/AM58_1044.pdf

Endimion17 - 31-8-2012 at 02:42

Burn the granules in a stream of air. If it's pure charcoal, very little residue will be left.
Activated charcoal has some desiccant properties, but it's used mainly for absorbing other molecules, as it's quickly saturated with water vapor.