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Occurrence forms of key ash-forming elements in defatted microalgal biomass

Henskens, Y.M.C., Gao, X.ORCID: 0000-0003-2491-8169, Qiao, Y. and Xu, M. (2017) Occurrence forms of key ash-forming elements in defatted microalgal biomass. Fuel, 200 . pp. 182-185.

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This study reports occurrence forms of key ash-forming elements in a defatted microalga, and for comparison, its corresponding raw microalga. Freeze-dried powders of a marine microalga (Nannochloropsis oceanica) were sieved to a size fraction of <75 μm and used as raw microalga. The raw microalga was then extracted with hexane to remove crude lipids and prepare a defatted microalga. The raw and defatted microalgae were subjected to chemical fractionation analysis, i.e., sequential leaching in H2O, 1.0 M ammonium acetate (NH4Ac), and 1.0 M hydrochloric (HCl) acid. The results demonstrate that, whereas the contents of Fe and Al in the raw and defatted microalgae are extremely low, those of other ash-forming elements follow a sequence of Cl > K > P > Mg > Na > Ca. Chemical fractionation results suggest that virtually all of the Na, K, and Cl in the raw and defatted microalgae are water-soluble. While majority of P in the two fuels are water-soluble and acid-soluble, most of Mg and Ca are leached in water and NH4Ac solution. As determined via chemical fractionation analysis, lipid extraction leads to the content of water-soluble Ca in the defatted microalga being ∼69.6% higher than that in the raw microalga counterpart, which is accompanied by a reduction in the amount of Ca leached in NH4Ac solution. Similar trend is also observed for Mg, but to a lesser extent.

Item Type: Journal Article
Murdoch Affiliation(s): School of Engineering and Information Technology
Publisher: Elsevier BV
Copyright: © 2017 Elsevier Ltd
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