Magnetophoretic separation is a promising technology for rapid algal separation or removal from water. This presentation will demonstrate the application of magnetic magnetite nanoparticles (MNPs) coated with a cationic polymer, polyethylenimine (PEI), toward the separation of<i> Scenedesmus dimorphus</i> from the medium broth. The influences of surface coating, UV irradiation, particle size, and magnetic field on the magnetophoretic separation were systematically examined. After PEI coating, zeta potential of MNPs shifted from -7.9 ± 2.0 mV to + 39.0 ± 3.1 mV at a pH of 7.0, which significantly improved algal separation (e.g., harvesting efficiency increased from 80.3 ± 1.4 % to 84.3 ± 0.9 %) and reduced the dose of MNPs. This improvement was explained by the extended Derjaguin−Landau−Verwey−Overbeek theory that predicted that the primary energy minimum between PEI-coated MNPs and algae was more negative than that between naked MNPs and algae. By contrast, the primary particle sizes significantly affected the optimal dose and algal harvesting efficiency. The overall aim of this work is to contribute to the development of sustainable engineering processes for algae biomass harvesting from water.

Applications of polymer-coated magnetic nanoparticles for algal biomass harvesting

249th National Meeting (2015)

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