I'm currently using Nafion 211 for the proton exchange membrane in my microbial fuel cell experiment. I found lots of articles recommended to use Nafion 117 instead. My experiment was failed, there was no power generated by the fuel cell and I suspect the Nafion 211 can not facilitate the proton exchange in the MFC.
I'm wondering what the difference between 117 and 211 is and could Nafion 211 use for MFC?
The thickness is difference, 117 is 7x more thicker. Thickness is 1 mil for 211 and 7 mil for 117: https://www.nafion.com/en/products/sulfonic-membranes
And 11 and 21 is Equivalent Weight - fraction between weight of dry membrane and number of sulfuric groups.
Hi Siyang Shen,
The main difference between Nafion® 117 and Nafion® 211 is their thickness. Nafion® 117 is 7 times thicker (183 microns thickness), while Nafion 211 thickness is 25 microns, as explained by Fiala sir.
In addition, Nafon® membranes present numerous problems during configuration and fabrication of MFCs, including oxygen leakage from cathode to anode, water permeability, substrate loss, transport crossover of cations other than protons like Na+, K+, NH4 +, Ca2+ and Mg2+ (which present a cation concentration 105 times higher than that of protons), dehydration at high temperatures, and biofouling.
Therefore, if the thickness of membrane is lower, leakage of oxygen from cathode to anode, water permeability and substrate loss will be higher. Furthermore, operating conditions and biofouling have a significant effect on configuration and fabrication of MFCs.
Additionally, it is important to ensure that the resistance of the membrane is small enough as to reduce ohmic losses in proton transport through the membrane.
To have deep knowledge about Nafion® membranes go through the attached file.
Ref. DuPont™ NafionR PFSA Membranes report (http://www2.
dupont.com/FuelCells/en/US/a_sets/downloads/dfc101.pdf).
the difference must be the thickness, thickness also should be optimum for conducing protons,
Nafion 117 is 7 mil thick
Nafion 211 is 1 mil thick
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