Difference Between Absorption And Desorption

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Adsorption is the bond of particles, particles, or atoms from a gas, fluid, broken down and attached strongly to a surface. This procedure makes a film of the adsorbate on the surface of the adsorbent. This methodology varies from absorbtion, in which a liquid (the absorbate) pervades or is absorbed by a porous solid. Adsorption is a surface-based procedure while absorption includes the entire volume of the material. The term sorption envelops both methodologies, while desorption is the converse of it.
Adsorption is the deposition of atoms or molecules on the surface of a substance. This creates a layer of the adsorbate (the molecules or atoms that are being collected) on the adsorbent material’s surface. It is different from absorption, in
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Selectivity and capacity are related, but there are various distinct areas of comparison that will be discussed. Primarily important area in this regards is the ratio of the capacity of one molecule component to that of the other at a given fluid concentration [2]. As the concentration starts decreasing and moves towards zero, this ratio generally tends to a constant value. The concentrations of the required molecule may not be near zero, so the application of definitions such as these becomes impractical in those cases. Relative volatility is the closest analogy ( in distillation). In that the smaller the value of the relative volatility, the larger is the size of the required equipment. If the major component is not adsorbed much, it acts as carrier and this thus leads to a much better …show more content…
It is important primarily as the cycle time of a fixed bed adsorption process is controlled by it. Fast kinetics results in a sharp breakthrough curve, while slow kinetics may lead to a distended and improper breakthrough curve with wrong interpretations. A distended breakthrough curve can be overcome by increasing the cycle time, and by adding adsorbent at the product side. The longer the cycle time, the greater is the amount of adsorbents needed and thus both these processes affect the amount of adsorbent needed in the entire operation. Despite this, kinetics has even been tested as the basis of adsorptive separations in various processes. In fact, the most common example is the pressure swing adsorption that uses carbon molecular sieve to remove nitrogen from air, which relies on fast diffusion of oxygen instead of very slow diffusing nitrogen. Normally, slow diffusion of any adsorbate is a major disadvantage. Small particles can be used for faster diffusion to compensate for the slow diffusing molecules but with the drawback of an increased pressure drop. The general solution to this problem is to use relatively larger particles and to use an extra section of adsorbent resulting in the increment of adsorbent

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