I thought I would write a quick post about activated carbon. I was using it the other day. Heating it on a deflagrating spoon and plunging it in oxygen to make (more) carbon dioxide.

As I was heating it, I noticed a couple of interesting things ….

(1) It looked as if my hand was shaking as the carbon was falling into the Bunsen flame. I don’t have that shaky a hand but the carbon was definitely jumping out of the spoon.

(2) When I took the carbon out of the flame, it looked fluid (similar to what you see when you decomposed copper carbonate into copper oxide)

One thing led to another and I decided to try and find out what was going on….

It turns out (according to Wkikpiedia 1) that activated carbon contains many many microscopic pores, so much so that 1g of activated carbon is estimated to have a surface area of 500m2!

Things started to make sense…

(1) The carbon was jumping out of the spoon as the air inside the grains and pores was expanding – as the grains are so light, this was obviously enough to push to grains out of the spoon and into the Bunsen.

(2) The hot expanded gas would also cause the carbon to take on its fluid like appearance – at least whilst it was hot enough.

If you have any other observations or suggestions about this I would like to hear them! :mrgreen:

1 http://en.wikipedia.org/wiki/Activated_charcoal