PALCUT Marián Slovak University of Technology in Bratislava, Faculty of Materials Science and Technology in Trnava

Spoluautoři GERULOVÁ Kristína, ŠPOTÁK Martin, ČAPLOVIČ Ľubomír, DOMÁNKOVÁ Mária

Magnetite (Fe3O4) nanoparticles are widely studied materials in biotechnology, biomedicine and catalysis. Fe3O4 has interesting magnetic properties. Fe3O4 is generally considered to be non-toxic in living organisms. As such, it can be employed in imaging and separation of biological systems. Recently, magnetic nanoparticles have been used in harvesting of marine and fresh water microalgae. Magnetic separation of algal cells from their culture medium by the use of Fe3O4 nanoparticles could be a promising method of harvesting, owing to its simple operation, high efficiency and low cost. In the present work, Fe3O4 nanoparticles were prepared by mixing aqueous solutions of FeCl2 and FeCl3 in molar ratio of 1:2 with aqueous ammonia. The reaction mixture was stirred continuously for 30 min at 353 K under flowing nitrogen atmosphere. The resulting black precipitate was concentrated by centrifugation and washed with distilled water. The prepared magnetite nanoparticles were stored in water. Subsequently, the nanoparticles have been investigated by high resolution scanning electron microscopy and energy dispersive x-ray spectroscopy. The crystal structure and size distribution have been further studied by means of high resolution transmission electron microscopy. Spherical nanoparticles with a diameter of 10 - 20 nm have been found. The prepared nanoparticles are relatively stable upon their storage in aqueous medium. Because of their relative stability, the prepared materials could be used in magnetic separation and microalgae harvesting. ACKNOWLEDGEMENTS This work was supported by the European Regional Development Fund (ERDF) via agreements ITMS:26220120014 and ITMS:26220120048 “Centre for development and application of advanced diagnostic methods in processing of metallic and non–metallic materials” and the Grant Agency VEGA of the Slovak Ministry of Education, Science, Research and Sport via projects no. 1/0068/14 and 1/0402/13. LITERATURE [1] GAWANDE, M. B., BRANCO, P.S., VARMA, R.S. Nano-magnetite (Fe3O4) as a support for recyclable catalysts in the development of sustainable methodologies, Chemical Society Reviews 2013, 42, 3371-3393. [2] REDDY, L. H., ARIAS, J. L., NICOLAS, J., COUVREUR, P. Magnetic nanoparticles: Design and characterization, toxicity and biocompatibility, pharmaceutical and biomedical applications, Chemical Reviews 2012, 112, 5818-5878. [3] HYEON, T. Chemical synthesis of magnetic nanoparticles, Chemical Communications 2003, 927-934. [4] HU, Y.-R., WANG, F., WANG, S.-K., LIU, C.-Z., GUO, C. Efficient harvesting of marine microalgae Nannochloropsis maritime using magnetic nanoparticles, Bioresource Technology 2013, 138, 387-390.