I am oxidizing a complex mixture in an H-cell. The positive side ( anode) normally oxidizes the material, the negative side (cathode) reduces. However, today, everything has reveresed itself. I am getting oxidation at the cathode, rather than the anode. Do I have metal ions trapped in the frit? That is my only explanation as I see bubbles forming at the frit on both sides. I am using Platinum electrodes. I know copper was used in it prior. I tried clening it out with EDTA to remove an extra metal ions. Any advice, especially on cleaning is appreciated.
I suggest your frit is now highly resistive: the H-cell acts as two series-connected cells. If metalic Cu is present, the frit must be cleaned with an acidic and oxidative solution (e.g., HNO3)
Neither cleaning with 1N HNO3 overnight, nor a new H-cell that has never been used before solved the problem. Nothing wrong with power supply either, has proper polarity. The only conclusion is that the complex organic mixture is now acting as a second pair of electrodes at the frit. What is strange is that this was not observed with the same mixture prior. Has anyone ever experienced this?This will defientely present problems later as we will be no longer oxidizing or reducing material with Pt, but some unknown compunds.
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