# Reduction by Activated Carbon

Does reduction by carbon itself occur when filtration is performed using activated carbon? Is it part of the central mechanisms involved in activated carbon filtration?

One of the specificities of all activated carbon, per my understanding, is it's large surface area, which allows it to be treated in a way or another and maximize the surface area on which the respective reaction occurs. Now, just as all activated carbon has a high surface area (with some variations), can it be said that all activated carbon acts as a highly potent reducer on some ions?

• Activated carbon is active mainly toward neutral and rather nonpolar substances, where reversible adsorption occurs based on van Der Waals force. It does not act as a ion reducer. – Poutnik Sep 1 '20 at 15:07
• @Poutnik: Can't it accept oxygen to turn into CO2 or CO in an aqueous solution? – Hans Sep 1 '20 at 19:19
• Carbon is quite inert wrt oxidation at ambient temperature, only strongest oxidation agents are able to partially oxidize e.g. graphite. But definitely not to CO2. – Poutnik Sep 1 '20 at 19:21
• Activated carbon adsorbs unpolar substances. There is no chemical (re)activity. – Karl Sep 1 '20 at 19:43
• @Hans Dispersed carbon may be used as a substrate (think like an air craft carrier) for transition metals like platinum, rhodium, etc; then the metal decorated sites (think like its air planes ready to go) may reduce, e.g. $\ce{C=C}$ double bonds of alkenes / aromatic cycles into $\ce{C-C}$ single bonds. Activated undecorated, metal free carbon alone typically is used to retain by adsorption (attraction on the surface) unpolar substances (e.g., cleaning prior to recrystallization, gas mask) and sometimes transition metal ions. But these weak attractive forces are not very specific. – Buttonwood Sep 2 '20 at 7:18

The only case I know of where activated carbon causes reduction at room temperature would be filtration of ozone, $$\ce{O3}$$. Even fluorine will not oxidize plain carbon:
Carbon is stable in a fluorine atmosphere up to about $$\pu{400 ^\circ C}$$ .
Oh, well perhaps dioxygen difluoride, $$\ce{FOOF}$$, could also oxidize carbon (or could be reduced by carbon, should you prefer a passive voice). Read Derek Lowe's Things I Won’t Work With: Dioxygen Difluoride, if you'd care to test that. Please let me know so that I could arrange to be elsewhere.