Thursday, March 5, 2009

Silica, a problematic metal in of herbaceous biomass

It is known that about 3–10% of total feedstock (dry matter) is the residue remaining after ignition (dry oxidation at 575 ± 25°C) of herbaceous biomass. It is composed of minerals such as silicon, aluminum, calcium, magnesium, potassium, and sodium.

During hot water and acid pretreatment, silica will be extracted and soluble in acid solution. When raising pH using alkali, silica (or silica oxide) will be hydrated to form some kind of flocs. As a result, it will precipitate into cells to cause problems for cell growth and scaling problem for the equipment. It can also form complex with some organic compounds which interfere with the process and even fermentation.

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