Hello.

Al is the anode in the reaction of reduction of Cr (VI) to Cr (III).

Cheers!

YES, as MARIO SILVA stated above: It is reduction of Cr6+ to Cr3+.

Best regards

Vit

Thanks for your response, Mário Silva Vit Mateju. Yes, you're right. hence, oxidation–reduction is the mechanism of this process, is it right?

I'm working on aqueous solution containing Cr (VI). What makes me wonder is that during the EC process, the pH of the solution decreases, and at the end of the reaction time, the settled solution is not observed. In addittion, as seen from the final solution, the aluminum electrode does not work.

Test conditions: pH = 7, current = 1,1.5,2,2.5A, Time = 10,20,30,40, Electrode= Al(4), monopolar

What reaction do you think is happening in this process?

Best regards

Well, you will need to look into more detail about the conditions you have to come up with an answer to your question. Keep in mind that the oxidation/reduction reactions are only somewhat selective depending on the "normal" reduction potential of the species present and the set-points of your electrode system.

- Try to identify all ionic species that you have in solution.

- Check possible reduction reactions for all of them.

- Check normal reduction potential for each of the possible reactions.

- Look at this against the conditions of your experiment and understand which reactions are most likely to happen.

I think this is the best way to do it, as you will, most likely, have several reduction reactions competing with each-other.

Good luck.

Thanks so much for your positive feedback, Mário Silva

In fact, this solution contains MgCl2 and Nacl salts with Cr (VI). Which has been kept for several months ago.

Yes, the conditions that you said should be considered.

Do you think there might be another reasons? which we do not see the treated solution after the process?

This could be due to insufficient release of hydroxyl ions during the process, or maybe due to the lack of efficiency of the aluminum electrode?