Sciencemadness Discussion Board

AC filter with H202 solution - always decomp of the H2O2?

RogueRose - 13-2-2018 at 13:26

I poured some solution that probably had some excess H2O2 in it and I noticed some bubbles being emmited but I can't be sure that it isn't air trapped in the carbon. It seemed that only the submerged carbon was bubbling but the carbon on top of the carbon wasn't bubbling. What's the deal with AC and H2O2, some reports show that it is a catalyst and others say it can be filtered.

If it is reacting, is it forming O2 & H2O or could it be forming some CO2 somehow?

JJay - 13-2-2018 at 14:19

I'm not sure offhand... you could solve the Gibbs free energy equation of CO2 formation from carbon and hydrogen peroxide and see what temperature is required.

https://www.khanacademy.org/science/chemistry/thermodynamics...

happyfooddance - 13-2-2018 at 14:32

It's probably just gas adsorbed on the carbon. Carbon can adsorb a ridiculous amount of gas on its surface. I make carbon boiling chips, and when I throw them in cold water or alcohol, they release a constant stream of bubbles.

Storing them in the freezer in a not-sealed container greatly increases the amount of air adsorbed, try it.

AJKOER - 17-2-2018 at 11:02

At least two perspective on how activated carbon can decompose H2O2.

First, AC can attract dust particles (including metals particles, oxides,..) and organics, where many of the latter impurities could foster a decomposition of the H2O2 into water and oxygen.

Second, from an electrochemical vantage, the AC can act as an electrode (for example, employable in a metal-air battery) to facilitate the transport of atmospheric O2 into dissolved oxygen. The latter than can feed electrochemical/standard chemical reactions depending on again metal impurities present, likely leading to the consumption of H2O2.