If I understand correctly it is possible to trap stuff inside activated charcoal pores to give it specific retention properties (by exposing it to functionalizing compounds while heated to open up the pores?).

When a solution for instance is passed through activated AC, what happens inside the pores with the functionalizing compound to trap stuff that otherwise wouldn't be trapped? Can it be said that the functionalizing compound precipitates stuff inside the pore by producing low solubility products?


No. It is not a precipitation reaction. It is physical reaction. The pores are made of the rest of the membranes of the cells. When wood is overheated in air, it burns. When this is done without too much contact with the air, the cellular water gets evaporated. The content of the cell (cytoplasm, proteins, etc.) is pyrolyzed, destroyed and mostly transformed into gases. The membrane is carbonized or charred, but remains here, forming charcoal. The rest of the cell being eliminated, the charcoal contains a huge amount of the previous cells which behave like pores. Big molecules can enter these shells, and have difficulty to get out later on.

  • $\begingroup$ Interesting! What about the functionalization? What happens in the pores that make functionalized AC retain more of some molecules? $\endgroup$ – Hans May 10 at 21:58
  • $\begingroup$ @Hans Honestly I believe that nobody knows how many molecules the pores may retain. $\endgroup$ – Maurice May 11 at 10:11
  • $\begingroup$ I'm talking about the mechanisms: What mechanisms is at hand / what is going on inside the pores of AC that has been functionalized with a chemical? Surely part of the specific chemical used (NaOH/KOH/CaCl2/ZnCl2 /H3PO4/...) must be retained within the pores and exert some activity in there specific to that chemical that gives the AC specific properties compared to AC activated with another chemical? $\endgroup$ – Hans May 11 at 11:33
  • 1
    $\begingroup$ @Hans. I don't have any idea about the mechanism $\endgroup$ – Maurice May 11 at 13:51
  • $\begingroup$ Okay. Thank you! $\endgroup$ – Hans May 11 at 23:16

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