Difference between revisions of "Microwave treatment"

|Name=Microwave pre-treatment}}

<onlyinclude>For '''microwave''' treatment electromagnetic radiation is utilised to induce thermal and non-thermal effects that drive physical, chemical or biological reactions<ref name=":0">{{Cite journal|author=Ethaib, S., Omar, R., Kamal, S. M. M., Biak, D. R. A.|year=2015|title=MICROWAVE-ASSISTED PRETREATMENT OF LIGNOCELLULOSICBIOMASS: A REVIEW|journal=Journal of Engineering Science and Technology|volume=January (2015)|page=97-109}}</ref>. The technology is usually utilised in food drying or to break down the structure of lignocellulosic biomass leading to the release of different substances (e.g. fermentable sugar).<!-- As a rapid and effective heating source with both thermal and nonthermal effects, MW can directly interact with the material, thereby accelerating chemical, physical, and biologic reactions. (Xu Jian, 2015) Microwave treatment causes a rise in the temperature within a penetrated medium as a result of rapid changes of the electromagnetic field at high frequency. (Lewandowicz et al. 2000) --></onlyinclude>

Lignocellulosic biomass<!-- MW irradiation has been successfully used in the pretreatment of various types of biomass including agricultural residues, woody biomass, grass, energy plants, and industrial residuals.(https://www.sciencedirect.com/science/article/pii/B9780128000809000098?via%3Dihub) -->

 

The breakdown of lignocellulosic biomass into its monomers and oligomers is induced via molecular collision due to dielectric polarisation<ref name=":1">{{Cite journal|title=Microwave heating processing as alternative of pretreatment in second-generation biorefinery: An overview|year=2017-03|author=Alejandra Aguilar-Reynosa, Aloia Romaní, Rosa Ma. Rodríguez-Jasso, Cristóbal N. Aguilar, Gil Garrote, Héctor A. Ruiz|journal=Energy Conversion and Management|volume=136|page=50–65|doi=10.1016/j.enconman.2017.01.004}}</ref>. Compared to other thermal treatments, the technology brings several advantages, such as reduced plant footprint, higher throughput, higher reaction rates, as well as higher yield and purity<ref name=":0" />. However, a disadvantage is the unequal distribution of the applied microwave power through non-homogeneous material (such as differences in composition, geometry, size) as well as local overheating through resonance (electromagnetic wave reflection and formation of standing waves) and low penetration for bulk materials <ref name=":1" />.

The process can also be combined with chemical treatments utilising chemicals such as [[Hydrolysis#Alkali|alkaline]] (to remove lignin) and [[Hydrolysis#Acid Acid|acid]] (to remove hemicellulose) solutions, ammonia, and [[Hydrolysis#Metal_salts|metal salts]]<ref name=":0" />.