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Nanomaterials 2018, 8(5), 292; https://doi.org/10.3390/nano8050292

Bare Iron Oxide Nanoparticles for Magnetic Harvesting of Microalgae: From Interaction Behavior to Process Realization

Bioseparation Engineering Group, Department of Mechanical Engineering, Technical University of Munich, Boltzmannstr 15, 85748 Garching, Germany
These authors contributed equally to this work.
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Received: 5 March 2018 / Revised: 18 April 2018 / Accepted: 27 April 2018 / Published: 1 May 2018
(This article belongs to the Special Issue Magnetic Nanoparticles in Biological Applications)
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Abstract

Microalgae continue to gain in importance as a bioresource, while their harvesting remains a major challenge at the moment. This study presents findings on microalgae separation using low-cost, easy-to-process bare iron oxide nanoparticles with the additional contribution of the upscaling demonstration of this simple, adhesion-based process. The high affinity of the cell wall for the inorganic surface enables harvesting efficiencies greater than 95% for Scenedesmus ovalternus and Chlorella vulgaris. Successful separation is possible in a broad range of environmental conditions and primarily depends on the nanoparticle-to-microalgae mass ratio, whereas the effect of pH and ionic strength are less significant when the mass ratio is chosen properly. The weakening of ionic concentration profiles at the interphase due to the successive addition of deionized water leads the microalgae to detach from the nanoparticles. The process works efficiently at the liter scale, enabling complete separation of the microalgae from their medium and the separate recovery of all materials (algae, salts, and nanoparticles). The current lack of profitable harvesting processes for microalgae demands innovative approaches to encourage further development. This application of magnetic nanoparticles is an example of the prospects that nanobiotechnology offers for biomass exploitation. View Full-Text
Keywords: magnetic nanoparticles; bare iron oxides; magnetic separation; microalgae; harvesting; recovery efficiency; electrostatic interaction; adsorption; adhesion; scale-up magnetic nanoparticles; bare iron oxides; magnetic separation; microalgae; harvesting; recovery efficiency; electrostatic interaction; adsorption; adhesion; scale-up
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

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Fraga-García, P.; Kubbutat, P.; Brammen, M.; Schwaminger, S.; Berensmeier, S. Bare Iron Oxide Nanoparticles for Magnetic Harvesting of Microalgae: From Interaction Behavior to Process Realization. Nanomaterials 2018, 8, 292.

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