Foam separation

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Foam separation is a chemical process which falls into a category of separation techniques called "Adsorptive bubble separation methods". [1] It is further divided into froth flotation and foam fractionation. Foam separation is essential in order to prevent contamination of fermentation medium through the foam by external microbes.

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Foam fractionation is a chemical process in which hydrophobic molecules are preferentially separated from a liquid solution using rising columns of foam. It is commonly used, albeit on a small scale, for the removal of organic waste from aquariums; these units are known as "protein skimmers". However it has much broader application in the chemical process industry and can be used for the removal of surface active contaminants from waste water streams in addition to the enrichment of bio-products.

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Aerated chocolate, also known as air chocolate, is a type of chocolate which has been turned into a foam via the addition of gas bubbles. The process for manufacturing it was invented by Rowntree's in 1935. During manufacturing the fluid chocolate mass is foamed with a propellant, and then cooled in a low pressure environment. As the bubbles of gas expand they cool and help set the chocolate. This helps to maintain an even bubble distribution within the chocolate. Due to the isolating effect of the bubbles, air chocolate melts differently from compact bar chocolate—the feeling of the chocolate melting is fragile-short at first, then as the chocolate is chewed it melts rapidly due to its bigger surface area.

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A breakthrough curve in adsorption is the course of the effluent adsorptive concentration at the outlet of a fixed bed adsorber. Breakthrough curves are important for adsorptive separation technologies and for the characterization of porous materials.

References

  1. Adsorptive bubble separation methods, R. Lemlich (1968) Industrial and Engineering Chemistry, Vol. 60 (10) 16-29