scholarly journals Modification of Nafion Membranes with Polyaniline to Reduce Methanol Permeability

2015 ◽  
Vol 162 (14) ◽  
pp. E325-E333 ◽  
Author(s):  
J. Gonzalez-Ausejo ◽  
L. Cabedo ◽  
J. Gámez-Pérez ◽  
S. Mollá ◽  
E. Giménez ◽  
...  
Keyword(s):  
Methanol Permeability ◽  
Nafion Membranes

The Influence of Chitosan Membrane Properties for Direct Methanol Fuel Cell Applications

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Peter O. Osifo ◽  
Aluwani Masala
Keyword(s):  
Fuel Cell ◽  
Water Content ◽  
Membrane Resistance ◽  
Membrane Properties ◽  
Methanol Permeability ◽  
Chitosan Membrane ◽  
Nafion Membranes ◽  
Direct Methanol ◽  
Chitosan Membranes ◽  
Methanol Fuel Cell

The chitosan membranes with different degrees of deacetylation (dda), prepared from Cape rock lobster collected from the surroundings of Cape Town, South Africa were characterized for suitability in methanol fuel cell applications. A comparison of chitosan membranes characteristics and that of conventional Nafion 117 membranes were made. Following this, the chitosan membranes were chemically modified with sulfuric acid to improve its proton conductivity and mechanical properties. A mass balance on proton transfer across the membrane resulted in a second order differential equation. Experimental data fitted into the equation gives a linear curve that was used to determine the membrane resistance. It was found that the dda of the chitosan membranes affected the water uptake, thereby affecting the proton flow. At a temperature of 20°C, chitosan membranes with a difference of 10% dda have a difference of about 5% water content. Chitosan membranes with a lower dda were found to have higher water content resulting in lower membrane resistances to proton flow. The water content of chitosan membranes was higher than Nafion membranes. The average resistance to proton flow for chitosan membrane was 53 min/cm and a Nafion membrane was 78 min/cm. Thermogravimetry analysis shows that chitosan membrane with higher dda is more thermally stable than chitosan with lower dda, Nafion membranes were more stable at higher temperature than chitosan membranes, Nafion membranes could decompose at temperature of 320 °C while chitosan membranes at 230 °C. Methanol permeability through chitosan membrane of higher dda was more than with one lower dda, however, the permeability through chitosan was three times lower when compares to Nafion membranes under the same temperature and pressure conditions. The performance of chitosan membranes and Nafion 117 membranes measured from a single cell DMFC with Pt-Ru/C anode catalysts and Pt/C cathode catalysts showed that Nafion membranes have a better performance. This was because the current and peak power densities determined for Nafion membranes were 0.56 A/cm2 and 0.075 W/cm2, respectively, and for Chit-I, were 0.22 A/cm2 and 0.0274 W/cm2, respectively, and for Chit-II membrane, were 0.26 A/cm2 and 0.0424 W/cm2, respectively.

Investigation of Methanol Permeability and Ionic Conductivity of EMI[sup +]-Doped Nafion Membranes

2004 ◽  
Vol 151 (7) ◽  
pp. A1020 ◽  
Author(s):  
Robert A. Banaszak ◽  
Sara A. Arbaugh ◽  
Elanor D. Steffee ◽  
Radha Pyati
Keyword(s):  
Ionic Conductivity ◽  
Methanol Permeability ◽  
Nafion Membranes

Methanol permeability and proton conductivity of Nafion membranes modified electrochemically with polyaniline

2008 ◽  
Vol 184 (2) ◽  
pp. 338-343 ◽  
Author(s):  
Q.M. Huang ◽  
Q.L. Zhang ◽  
H.L. Huang ◽  
W.S. Li ◽  
Y.J. Huang ◽  
...  
Keyword(s):  
Proton Conductivity ◽  
Methanol Permeability ◽  
Nafion Membranes

Use of Nafion membranes in laboratory organic electrosynthesis

1988 ◽  
Vol 53 (12) ◽  
pp. 3164-3170 ◽  
Author(s):  
Jaromír Hlavatý ◽  
Jiří Volke
Keyword(s):  
Glassy Carbon ◽  
Quaternary Ammonium ◽  
Tetrabutylammonium Bromide ◽  
Nafion Membrane ◽  
Carbon Anode ◽  
Tetrabutylammonium Hydroxide ◽  
Nafion Membranes ◽  
Divided Cell ◽  
A Cell ◽  
Tetrabutylammonium Iodide

Electrolysis of quaternary ammonium bromides and iodides in a divided cell with a Nafion membrane yields quaternary polyhalogenides at a carbon anode in water-ethanolic anolytes. The electrodialysis of tetrabutylammonium iodide in a cell with a Nafion membrane enables generation of tetrabutylammonium hydroxide. In electrolytic reduction of nitrobenzene in presence of 1,3-dibromopropane, N-phenylisooxazolidine results in an approx. 60% yield. This electrosynthesis takes place in dimethylformamide with tetrabutylammonium bromide at a glassy-carbon cathode in a divided cell. In the electroreduction of lobelanine hydrogensulfate in a divided cell in acid water-ethanolic media at a lead cathode prevalently lobelanidine has been obtained.

Electron beam patterned Nafion membranes for DMFC applications

2013 ◽  
Vol 228 ◽  
pp. 151-158 ◽  
Author(s):  
Ayokunle Omosebi ◽  
Ronald S. Besser
Keyword(s):  
Electron Beam ◽  
Nafion Membranes

Transient Water Transport in Nafion Membranes Under Activity Gradients

2010 ◽  
Author(s):  
T. Romero ◽  
W. Me´rida
Keyword(s):  
Water Content ◽  
Water Transport ◽  
Water Activity ◽  
Thickness Variation ◽  
Membrane Thickness ◽  
Membrane Interface ◽  
Rational Representation ◽  
Transport Measurements ◽  
Nafion Membranes ◽  
The Time Domain

Transient water transport experiments on Nafion of different thicknesses were carried out in the temperature range of 30 to 70 °C. These experiments report on water transport measurements under activity gradients in the time domain for liquid and vapour equilibrated Nafion membranes. Using a permeability test rig with a gated valve, the water crossover was measured as a function of time. The typical response is shown as a time dependent flux, and it shows the dynamic transport from an initially dry condition up to the final steady state. Contrarily to previous reports from dynamic water transport measurements, where the activity gradient across the membrane is absent; in this work, the membrane was subjected to an activity gradient acting as the driving force to transport water from an environment with higher water activity to an environment with lower water activity through the membrane’s structure. Measurements explored temperature and membrane thickness variation effect on the transient response. Results showed dependency on temperature and a slower water transport rate across the vapour-membrane interface than for the liquid-membrane interface. These measurements showed the transport dependency on water content at the beginning of the experiment when the membrane was in a close-to-dry condition suggesting a transport phenomenon transition due to a reached critical water content value. The new protocol for transient measurements proposed here will allow the characterization of water transport dependency on membrane water content with a more rational representation of the membrane-environment interface.

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