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Difference between revisions of "Extraction"
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=== Pre-treatment === | === Pre-treatment === | ||
Various pre-treatments may be utilised | Various pre-treatments may be utilised. Physical pre-treatments are mainly used to make the extractable substances acessable, e.g. by incresing the surface area of the feedstock (through [[Sizing]]<nowiki/>and [[Steam explosion]]) and/or to release extractable substances e.g. via cell disruption (through [[Microwave treatment]] or [[Ultrasonication]]). | ||
==Process and technologies== | ==Process and technologies== | ||
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The first category consists of mixers-remixers (mixer-settlers), where the extraction process consists of two separate steps. In the first step, the two liquids are mixed to enable substance transfer. In the second step, the two liquids are separated. The two steps can take place in separate reactors. | The first category consists of mixers-remixers (mixer-settlers), where the extraction process consists of two separate steps. In the first step, the two liquids are mixed to enable substance transfer. In the second step, the two liquids are separated. The two steps can take place in separate reactors. | ||
The second category uses columns in which the two liquids are in continuous contact with each other. Here, typically special measures are taken to increase the contact surface between the feed and extraction flow (e.g. dispersion of one liquid, use of trays or packing material | The second category uses columns in which the two liquids are in continuous contact with each other. Here, typically special measures are taken to increase the contact surface between the feed and extraction flow (e.g. dispersion of one liquid, use of trays or packing material). | ||
Liquid-liquid extraction is a process that separates substances based on their chemical properties. The principle consists of bringing the contaminated feed flow into contact with a second fluid, i.e. the extraction fluid. The extraction fluid is chosen in such a way that it does not mix with the supply flow and that it dissolves the pollutant well. During the extraction process, the contamination of the supply flow will (partially) transfer to the extraction fluid, until a balance in concentration has been reached. This balance depends on the affinity the pollutant has for the extraction fluid. If several substances are present, the balance will be substance-dependent. In an additional step, the pollutant is separated from the extraction fluid so it can be reused. | Liquid-liquid extraction is a process that separates substances based on their chemical properties. The principle consists of bringing the contaminated feed flow into contact with a second fluid, i.e. the extraction fluid. The extraction fluid is chosen in such a way that it does not mix with the supply flow and that it dissolves the pollutant well. During the extraction process, the contamination of the supply flow will (partially) transfer to the extraction fluid, until a balance in concentration has been reached. This balance depends on the affinity the pollutant has for the extraction fluid. If several substances are present, the balance will be substance-dependent. In an additional step, the pollutant is separated from the extraction fluid so it can be reused. | ||
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=== Post-treatment === | === Post-treatment === | ||
Various post-treatments may be utilised during or after the extraction process which includes: | |||
* [[Ionic liquids]] | |||
* [[Microwave treatment]] | |||
* [[Centrifugation]] | |||
* [[Membrane filtration]] | |||
* [[Sieving]] | |||
* [[Crystallisation and precipitation]] | |||
* [[Flocculation]] | |||
* [[Field-Flow fractionation (FFF)]] | |||
==Technology providers== | ==Technology providers== | ||