While operating sediment microbial fuel cell as paddy soil for inoculum and substrates in oligotropic condition, the colour of soil changes to reddish in all reactors. The initial colour was grey. Expecting answers from experts. Thank you in advance.
Dear Professor Towe,
Thanks for interest in answering. Result for soil properties yet to recieve from laboratory. pH and Conductivity however are 6.34 and 926 uS/cm respectively.
Thanks.
Initial LOI was around 7% . I beleive it might decrease with the operation of reactors. Oxidation of reduced iron make sense in Microbial Fuel Cell. Does reddiness signify decrease in organic content by time.
Dear Roshan,
Did you have some nitrate or nitrite? Some denitirfiers can oxidize Fe(II) using nitrate(nitrite) as electron acceptor(s).
You may consider also electrogenic oxidation of Fe(II). However, that could be not associated with the growth of bacteria. Redox potential Fe(OH)3/FeCO3 is ~ +0,1 V.
Best wishes Alexander.
Thanks Galushko,
Yes, reactors do have nitrate. Fe (II) is oxidized for sure whether via electrogenic or microbial. For denitifiers, hope phylogenetic analysis will help. Maximum potential I get from reactors is around .9 V
Thanks again for answer
Probably due to the oxidation of iron and also due to the effect of other biochemical changes that take place during operation.
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