Nanoparticle harvesting for microalgae used in heavy metal remediation

GISELA FERRARO; REGINA TORANZO; DELFINA CASTIGLIONI; NICOLAS FELLENZ; DANIEL PASQUEVICH; CAROLINA BAGNATO

Buenos Aires

Congreso; 5º Simposio Internacional de Ingenieria Ambiental; 2016

UNSAM ISEBE

Microalgae are photosynthetic microorganisms that can be found in both marine and freshwater environments. Microalgae are important biological resources that have a wide range of biotechnological applications such as bioenergy production and wastewater remediation. However harvesting microalgae biomass from diluted cultures is one of the bottlenecks for their industrial applications. Many separations methods like centrifugation, filtration and flocculation have been developed for microalgae recovery. Nevertheless, there is still a great interest to develop new economic and more efficient approaches for the harvesting of microalgae. One of the new alternatives to overcome this limitation is the use of magnetic nanoparticles. In our lab we have successfully applied the use of the naked Fe3O4 nanoparticles in the harvesting of Chlorella vulgaris with 94-100% efficiency. Despite of the promising results in this area, there is still a lack of studies regarding the use of these nanoparticles for the harvesting of microalgae in bioremediation processes.In this study we have applied the use of Fe3O4 nanoparticles for the harvesting C vulgaris cultures with adsorbed Zn in their cell walls. We have assayed the efficiency of the harvesting process in C. vulgaris cultures used for the bioremediation of Zn ions. Operation parameters such as different kind of nanoparticle suspension and doses, pH effect and Zn removal amount were assessed. The effect of adsorbed Zn in the cell wall in the interaction of nanoparticles with the microalgae, that in last instance affects the harvesting efficiency, was also studied. The outcomes of these experiments have put some light in the use of nanoparticles for heavy metal remediation by microalga