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As we saw in the previous blog post, the process of ion exchange is influenced by a very large number of factors. The primary mode of ion transport is diffusion, which is process of the movement of atoms, ions, molecules, or energy from a region of high concentration to a region of low concentration.
Ion exchange materials are used to purify, separate, and extract many different types of molecules, including organic and biochemical molecules. When ion exchange materials involve these ion types, there may be additional complexities involved with the interaction.Some of the phenomena that may occur are:
- Secondary forces between the ionized group and counterion. These forces may consist of coordination, hydrogen, and van der Waals bonding.
- The pH can affect the percent ionization.
- The position of the functional groups can affect ion transport.
- Hydration of organic molecules can be more complex than inorganic ions.
- Organic ions may be larger than inorganic ions; thus, steric hinderances can reduce ionic interactions.
Therefore, ion exchange phenomena may be able to be explained chemically by stoichiometric reactions, but the actual ionic selectively may be determined by other interactions.
Membranes are essential for PEM fuel cells to operate. The Proton Exchange Membrane carries the hydrogen ions from the anode to the cathode without passing the electrons that were removed from the hydrogen atoms.
The Fuel Cell Store carries the largest selection of Membranes in the world! We help you compare all the Membranes we offer in one simple file so you can narrow down the perfect Membrane for your project. With our Membrane Comparison Table you can compare the specifications of all our Cation Exchange Membranes, Anion Exchange Membranes, and Bipolar Membranes with ease.
Gas Diffusion Layers (GDL) are one of the components in different types of fuel cells including, but not limited, to Proton Exchange Membrane and Direct Methanol fuel cells. Gas Diffusion Layers serve to provide conductivity in the cell and control the contact between the reactant gases and the catalyst. This layer also aids in managing the water transport out of the membrane. Another essential function of a GDL is to provide a connection between the membrane electrode assembly and graphite plates in the fuel cell stack.
A numerical model was developed to predict the water concentration, temperature, potential and pressure across a Nafion membrane used in proton exchange membrane (PEM) based fuel cells. The numerical model consists of simultaneously calculating the diffusive flux for water and hydrogen, the proton potential and the pressure and temperature at each node...
Ion-exchanges membranes (IEMs) have many applications beyond fuel cells -- they can also be used to synthesize all types of compounds that are used in various industries. The most popular IEMs consist of polymeric resins with charged functional groups based upon their ion selectivity, they are referred to as anion-exchange (AEM) and...