Introduction to Adsorption

• published: 31 Oct 2014
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READ!!: WATCH IN 720P! This is a brief Introduction to adsorption, showing the basics for anyone with no prior knowledge to adsorption, and without the technical knowledge. Comment and like it and subscribe. All images have been either produced by me or used under no copyright. Here's a more in-depth introduction: Adsorption is a phenomenon whereby free particles (solid molecules/ liquid/ gas molecules) are attracted and bind with the surface; or it can be simply defined as condensation of particles on free surfaces. The phenomena of adsorption can be observed in everywhere from the charcoal deodorizer to the fixed bed contaminant removal in chemical industries. Adsorption involves two components — adsorbate (particle that is being adsorbed) and adsorbent (the surface provided for the adsorption). Adsorption is a surface phenomenon. It arises due to the presence of unbalanced forces at the surface. These unbalanced residual forces have tendency to attract the particle which comes in contact with the surface. There are 2 types of adsorption. We can classify it into physisorption and chemisorption. Physisorption is an adsorption process which involves physical bonding between the adsorbate with the adsorbent due weaker interaction involving polarization rather than electron transfer. Chemisorption is an adsorption process involving the formation of chemical bonding between the adsorbate and the adsorbent and it requires activation energy. In this video we will introduce the phenomena of adsorption by activated charcoal. Activated charcoal also known as activated carbon is a form of carbon which has been activated either through physical reactivation or chemical reactivation. The surface of activated charcoal exhibits remarkably low reactivity and therefore favours physisorption. Activated carbon has high micro-porosity which significantly provides a high surface area available for adsorption. Due to this property, an activated charcoal has a larger capacity for adsorption and can attract gas particle more effectively than a normal charcoal. Thus, it can be used to remove odours and smoke. The process of adsorption of gas particle on activated charcoal is a spontaneous reaction. However, this adsorption process is fairly slow and a certain time is required for the adsorption process to show visible results. Gas particles lose their momentum, hence possess a low energy level, resulting in being trapped on the surface of activated charcoal as they don’t have enough energy to break the interaction forces between particles and the surfaces. Hence, it can be observed that the smoke and odours can be eliminated by activated charcoal for a period of time. The principle of adsorption is utilized in the recovery of high-purity nitrogen from a supply of compressed air using Pressure swing adsorption (PSA) technique. The adsorption nitrogen generator contains CMS (carbon molecular sieves) – a porous carbon systematic adsorbent which is selective to oxygen in compressed air. Oxygen molecules are separated from the compressed air content in a very short time, and released to the atmosphere upon depressurizing, leaving a high-purity nitrogen. The principle of adsorption is also applied in the water treatment industries. In the water softening process, ion-exchange resins are used to replace magnesium and calcium ions found in hard water with sodium ions. These resins contain sodium ions at its active sites. Upon contacting with the hard water, the magnesium and calcium ions will migrate out of solution and bind to the active site on the resin, replaced in solution by sodium ions. Song name: I.D.G.A.F.O.S - Dillon Francis.