In electro-Fenton system, we would like Fe2+ could be effectively regenerated and function as a catalyst. However, it is known that as a positive ions, cathode would absorb Fe2+, resulting in a located distribution of Fe2+ in the cathode zone.
How to deal with this problem?
You are considering a hypothetical system. This is not correct ; "However, it is known that as a positive ions, cathode would absorb Fe2+" Numerous papers are published in this area., e.g. http://dx.doi.org/10.1016/S0043-1354(02)00064-7
You are considering a hypothetical system. This is not correct ; "However, it is known that as a positive ions, cathode would absorb Fe2+" Numerous papers are published in this area., e.g. http://dx.doi.org/10.1016/S0043-1354(02)00064-7
If you manage to produce Fe2+ at the cathode, for example, by doing electrolysis at a constant potential, then this ions will diffuse in solution bulk unless they react with something along the way. The fact that Fe2+ is a positive ion does not necessarily means that this and all other cations will migrate to the cathode. With sufficient levels of a background electrolyte, the migration of Fe2+ will be effectively suppressed and it will spread away from the electrode by diffusion. And even if there is some contribution from the iron (ii) migration towards the cathode, if you generate them, sooner or later there should be a significant flux away from the electrode. Remember that in aqueous solution pH may increase at the cathode if side reaction of H2 evolution takes place, and all your iron will precipitate.
Try cyclic voltammetry. It is a useful analytic method.
Hi Dr. Cuharuc,
Thanks for your answers. So can I understand in this way: Fe2+ and Fe3+ can diffuse and disperse uniformly since a lot of background electrolyte. However, pH of the zone near cathode is high, after regeneration, Fe2+ will surely precipitate. So, why do we say Fe2+ can be effectively regenerated in Electro-Fenton?
Thank you!
Wei
- Badges
- Science topic
- Similar topics
- Chemistry
- Electrochemistry