I've read that using blocks of charcoal can remove some odors from the air by placing them in the vicinity of the odors. (Maybe not as efficiently as other forms of carbon, as pointed out in the comments of that link, but something nonetheless.)

What is the chemical process by which charcoal can do that, and once the odors are 'gone', where do they 'go'? In the case of 'toxins in gases', what typically is done to them upon 'deodorizing' by the charcoal block - are they collected, neutralised / transformed upon contact, or something else?

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    $\begingroup$ The scent molecules are adsorbed by the charcoal. The higher the surface area of the charcoal the more smell it can absorb $\endgroup$ Aug 13, 2014 at 3:18
  • $\begingroup$ I know, but I'm wondering what chemical process this absorption is :). I've even read that they can be re-used after some 'airing out' so, if that's true, it's interesting to know what the process is! 'Stuff' (including odors and toxins in gases) can't just disappear, something happens to them! I'm wondering what it is in this case. $\endgroup$
    – user1469
    Aug 13, 2014 at 4:09

2 Answers 2


It is a form of carbon that has very large surface. The odors and impurities are held to the surface with Van der Waals forces. The capability of removing notable amounts of these impurities or odors is thanks to the extraordinarily large surface.


Its simple adsorption. The smells/ chemicals are stuck at the surface, and once you expose the activated charcoal to sunlight for a few hours, it release the smells and is again activated and charged, and good to use.

A good quality, with high adsorbent surface area activated charcoal kit can work good for a period of about 1 year, however you need to keep it in sunlight at-least once a month.


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