(For convenience, we have also multiplied the sum by F so that we get an expression with the unit of A/m 2 i.e., the total current density. In the case of Nafion®, the immobilized ions are \mathrm_i =0 The key feature of the ion-exchange membrane is the immobilized ions that are fixed to the backbone and located on the internal pore walls. 1.4 Physical Properties-Density, Viscosity, and Surface Tension. If the port number 2036 is taken, then COMSOL Server will use the next available port number: 2037, 2038, and so on. 1.3 Stresses, Pressure, Velocity, and the Basic Laws. In a web browser, go to you are accessing it remotely, use the computer name comput er name and domain, or the local IP address of your server instead of localhost). The pores, swelling when in contact with water, are in the range of nanometers. 1.1 Fluid Mechanics in Chemical Engineering. This material looks perfectly transparent and homogeneous, but the matrix is made of a transparent polymer backbone. Exercise 1: Intro to COMSOL Transport in Biological Systems Fall 2015 Overview In this course, we will consider transport phenomena in biological systems.
This may sound completely wrong to anyone who has seen, for instance, a Nafion® membrane, one of the most common polymer electrolyte materials. In this blog post, we will explore the ion-selective capabilities of ion-exchange membranes.Īn ion-exchange material is typically modeled as a porous medium consisting of a fixed matrix with the pores filled up with water and additional mobile ions. The ability to promote the passage of ions of either positive or negative charge is also used in electrodialysis for cleaning water from ions. In polymer electrolyte fuel cells and vanadium flow batteries, they are used to conduct ions and at the same time prevent reactants and electrons from crossing between the two flow compartments. Graphite (/ r æ f a t /), archaically referred to as plumbago, is a crystalline form of the element carbon with its atoms arranged in a hexagonal structure.It occurs naturally in this form and is the most stable form of carbon under standard conditions.Under high pressures and temperatures it converts to diamond.Graphite is used in pencils and lubricants. Ion-exchange membranes are widely employed within the field of electrochemical engineering.
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