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Difference between revisions of "Ultrasonication"
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| Feedstock = [[Biowaste]] | | Feedstock = [[Biowaste]] | ||
| Product = Biomass (dispersed, disrupted, emulsified, extracted, homogenised) | | Product = Biomass (dispersed, disrupted, emulsified, extracted, homogenised) | ||
|Name=Ultrasonication}} | |Name=Ultrasonication|Category=Pretreatment}} | ||
<onlyinclude>'''Ultrasonication''' is a physical treatment to disperse, disrupt, emulsify, extract, and/or homogenise biomass | <onlyinclude>'''Ultrasonication''' is a physical treatment to disperse, disrupt, emulsify, extract, and/or homogenise biomass via the application of ultrasonic frequencies (>20 kHz). The propagation of sound waves through the biomass results in spontaneous formation and collapse of microsized cavities. This activity produces a hot-spot effect, resulting in high temperature and pressure gradients to form locally, while the overall conditions remain ambient. This effect can be used to break down morphologies, for example for the depolymerisation of lignocellulosic biowaste.<ref name=":1">{{Cite book|author=Preeti Bhagwan Subhedar|year=2016|section_title=Use of Ultrasound for Pretreatment of Biomass and Subsequent Hydrolysis and Fermentation|book_title=Biomass fractionation technologies for a lignocellulosic feedstock based biorefinery|publisher=Elsevier|place=Amsterdam, Netherlands|ISBN=0-12-802561-1|editor=}}</ref></onlyinclude> | ||
==Feedstock== | ==Feedstock== | ||
=== | ===Composition=== | ||
The requirements on the | The requirements on the composition of the feedstock may vary since ultrasonication can be utilised at various points in the value chain of biowaste valorisation. | ||
=== Pre-treatment === | === Pre-treatment === | ||
Ultrasonication is often the first step of the pretreatment, although initial [[sizing]] may be required. | |||
== Process and technologies == | == Process and technologies == | ||
During the ultrasonication treatment, ultrasound is transmitted through any physical medium by waves that compress and stretch the molecular spacing of the medium through which it passes<ref name=":0">{{Cite book|author=Hugo Miguel Santos, Carlos Lodeiro, and José-Luis Capelo-Martínez|year=2008|section_title=The Power of Ultrasound|editor=José-Luis Capelo-Martínez|book_title=Ultrasound in Chemistry: Analytical Applications|publisher=Wiley‐VCH Verlag GmbH & Co. KGaA|ISBN=9783527319343|place=Weinheim, Germany}}</ref>. The distance between the molecules will vary as they oscillate about their mean position<ref name=":0" />. When the negative pressure is large enough, the distance between the molecules of the liquid exceeds the minimum molecular distance required to hold the liquid intact, and then the liquid breaks down and voids (cavitation bubbles) are created<ref name=":0" />. <!-- Maybe it is easier to understand when you add figures to the text. | During the ultrasonication treatment, ultrasound is transmitted through any physical medium by waves that compress and stretch the molecular spacing of the medium through which it passes<ref name=":0">{{Cite book|author=Hugo Miguel Santos, Carlos Lodeiro, and José-Luis Capelo-Martínez|year=2008|section_title=The Power of Ultrasound|editor=José-Luis Capelo-Martínez|book_title=Ultrasound in Chemistry: Analytical Applications|publisher=Wiley‐VCH Verlag GmbH & Co. KGaA|ISBN=9783527319343|place=Weinheim, Germany}}</ref>. The distance between the molecules will vary as they oscillate about their mean position<ref name=":0" />. When the negative pressure is large enough, the distance between the molecules of the liquid exceeds the minimum molecular distance required to hold the liquid intact, and then the liquid breaks down and voids (cavitation bubbles) are created<ref name=":0" />. | ||
The medium for ultrasonication can be water, an organic solvent, or a dilute acid or base.<ref name=":1" /> <!-- Maybe it is easier to understand when you add figures to the text. | |||
Some interesting links: | Some interesting links: | ||
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Ultrasonication can be used to produce: | Ultrasonication can be used to produce: | ||
* Emulsions (such as nanoparticles, nanoemulsions, nanocrystals, liposomes, wax emulsions) | * Emulsions (such as nanoparticles, nanoemulsions, nanocrystals, liposomes, wax emulsions) | ||
* Extracts from biomass (such as polysaccharides<ref>{{Cite journal|title=Polysaccharides from macroalgae: Recent advances, innovative technologies and challenges in extraction and purification|year=2017-09-01|journal=Food Research International|volume=99|page=1011–1020|doi=10.1016/j.foodres.2016.11.016}}</ref>, oil, anthocyanins and antioxidants<ref>{{Cite journal|title=Effect of ultrasound frequency on antioxidant activity, total phenolic and anthocyanin content of red raspberry puree|year=2013-09-01|journal=Ultrasonics Sonochemistry|volume=20|issue=5|page=1316–1323|doi=10.1016/j.ultsonch.2013.01.020}}</ref>) | * Extracts from biomass (such as polysaccharides<ref>{{Cite journal|title=Polysaccharides from macroalgae: Recent advances, innovative technologies and challenges in extraction and purification|year=2017-09-01|journal=Food Research International|volume=99|page=1011–1020|doi=10.1016/j.foodres.2016.11.016}}</ref>, oil, anthocyanins and antioxidants<ref>{{Cite journal|title=Effect of ultrasound frequency on antioxidant activity, total phenolic and anthocyanin content of red raspberry puree|year=2013-09-01|journal=Ultrasonics Sonochemistry|volume=20|issue=5|page=1316–1323|doi=10.1016/j.ultsonch.2013.01.020}}</ref>) | ||
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=== Post-treatment === | === Post-treatment === | ||
A common application for ultrasonication is breaking down the lignocellulosic structure. The available sugars can then be converted to products such as biofuels, for example by [[Industrial fermentation|fermentation]].<ref name=":1" /> | |||
== Technology providers == | == Technology providers == | ||