I am doing CFM with K3Fe(CN)6/PBS on the cathode side and whey with K. pneumoniae on the anode side. The problem is that the volume of the cathode is decreasing and the volume of the anode is increasing. It is a closed double chamber with graphene electrodes, titanium wire and Nafion membrane. Voltage will be generated, but the amps show 0 on the multimeter.
And I don't know what's going on. I am doing the measurements in open circuit (directly connected to the multimeter without the electrodes being linked by an external load).
Could someone tell me what's going on or how do I fix this, please?
When I used KnFe(CN)6 in PBS as electrolyte with carbon and "graphene" electrodes, the cyanide reacted quickly with my (silver) reference electrode at open circuit before any measurement started. This caused a continuous accumulation of reaction products on the reference electrode surface, which many others ignored (results published here: 10.1016/j.elecom.2019.106508). Even if the reaction rate is lower in other metallic electrodes, the same process might be occurring on your titanium, and the biological coating might also be trapping side reaction products. Can you check the surface of your anode for elemental changes, such as iron or cyanide signatures?
Hi,
Does this happen without voltage? It could be an osmotic pressure effect and solvent getting through the membrane. Try to have the same osmolarity on both sides.
Kyle
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