Hi, Karan,

Not an expert in MFC, but since salt concentration is increase, intertal resistance should decrease because of the increased ion concentration. Viscosity should not change much in your case. And since internal resistance decreases, it should be easier for the electrochemcail interface to reach equilibrium which can result in the decreased OCV (smaller overpotential).

Hope it helps,

Linxiao

Hi Karan,

as was pointed out in the previous responses, the ion transport through the electrolyte is critical for an electrochemical process. A low ionic conductivity of the electrolyte would increase the risk of an ion transport-limited process.

I recommend you this work:

Oliot M.; Galier S.; Roux de Balmann H.; Bergel A. Ion transport in microbial fuel cells: Key roles, theory and critical review. Applied Energy 183 (2016) 1682-1704

Moreover, in the case of microbial fuel cells you must consider that high salinity concentration will inhibit the activity of the majority of the microorganisms that are not capable to survive in saline (or hypersaline) conditions. 

I recommend you these other works where the influence of the salinity on the performances of MFCS was investigated:

Miyahara M.; Kouzuma A.; Watanabe K. Effects of NaCl concentration on anode microbes in microbial fuel cells. AMB Express 5 (2015) 34

Grattieri M.; Suvira M.; Hasan K.; Minteer S.D.; Halotolerant extremophile bacteria from the Great Salt Lake for recycling pollutants in microbial fuel cells. Journal of Power Sources 356 (2017) 310-318

Best,

Matteo

As Artur Braun. The conductivity[1] of the NaCl solution scales with the NaCl concentration, e.g. scales with the increase of charge carrier concentration.

1.  See the case of NaCl in : CONDUCTIVITY ORDERING GUIDE    http://myweb.wit.edu/sandinic/Research/conductivity%20v%20concentration.pdf

Thank you Mr, Matteo Grattieri and Ioannis Samaras for your guidance.