title: Magnetic-Nanoflocculant-Assisted Water-Nonpolar Solvent Interface Sieve for Microalgae Harvesting.
abstract: Exploitation of magnetic flocculants is regarded as a very promising energy-saving approach to microalgae harvesting. However, its practical applicability remains limited, mainly because of the problem of the postharvest separation of magnetic flocculants from microalgal flocs, which is crucial both for magnetic-flocculant recycling and high-purity microalgal biomasses, but which is also a very challenging and energy-consuming step. In the present study, we designed magnetic nanoflocculants dually functionalizable by two different organosilane compounds, (3-aminopropyl)triethoxysilane (APTES) and octyltriethoxysilane (OTES), which flocculate negatively charged microalgae and are readily detachable at the water-nonpolar organic solvent (NOS) interface only by application of an external magnetic field. APTES functionalization imparts a positive zeta potential charge (29.6 mV) to magnetic nanoflocculants, thereby enabling microalgae flocculation with 98.5% harvesting efficiency (with a dosage of 1.6 g of dMNF/g of cells). OTES functionalization imparts lipophilicity to magnetic nanoflocculants to make them compatible with NOS, thus effecting efficient separation of magnetic flocculants passing through the water-NOS interface sieve from hydrophilic microalgae. Our new energy-saving approach to microalgae harvesting concentrates microalgal cultures (∼1.5 g/L) up to 60 g/L, which can be directly connected to the following process of NOS-assisted wet lipid extraction or biodiesel production, and therefore provides, by simplifying multiple downstream processes, a great potential cost reduction in microalgae-based biorefinement.
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research (KIER) , 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea.
authors.forename: Kyubock
authors.initials: K
authors.lastname: Lee
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research (KIER) , 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea.
authors.forename: Jeong-Geol
authors.initials: JG
authors.lastname: Na
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST) , 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
authors.forename: Jung Yoon
authors.initials: JY
authors.lastname: Seo
authors.affiliation: Department of Chemical and Biomolecular Engineering and Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Tae Soup
authors.initials: TS
authors.lastname: Shim
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research (KIER) , 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea.
authors.forename: Bohwa
authors.initials: B
authors.lastname: Kim
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research (KIER) , 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea.
authors.forename: Ramasamy
authors.initials: R
authors.lastname: Praveenkumar
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research (KIER) , 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea.
authors.forename: Ji-Yeon
authors.initials: JY
authors.lastname: Park
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research (KIER) , 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea.
authors.forename: You-Kwan
authors.initials: YK
authors.lastname: Oh
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research (KIER) , 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea.
authors.forename: Sang Goo
authors.initials: SG
authors.lastname: Jeon
mesh_terms: D002708:Chlorella / Q000166:cytology / Q000302:isolation & purification*; D052203:Ferrosoferric Oxide / Q000737:chemistry; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D018613:Microscopy, Confocal; D009821:Oils / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D011437:Propylamines; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D058185:Magnetite Nanoparticles; D009821:Oils; D011437:Propylamines; D012821:Silanes; D012997:Solvents; D014867:Water; D012822:Silicon Dioxide; C477625:amino-propyl-triethoxysilane; C514699:octyltriethoxysilane; D052203:Ferrosoferric Oxide
keywords: functionalization; harvesting; interfacial tension; magnetic materials; microalgae; recovery