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Rapid Magnetophoretic Separation of Microalgae
Author(s) -
Lim Jit Kang,
Chieh Derek Chan Juinn,
Jalak Selah A.,
Toh Pey Yi,
Yasin Nur Hidayah Mat,
Ng Bee Wah,
Ahmad Abdul Latif
Publication year - 2012
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201102400
Subject(s) - magnetic separation , materials science , magnetic nanoparticles , ferrofluid , chemical engineering , nanoparticle , surface modification , nanorod , nanotechnology , magnetic field , physics , quantum mechanics , engineering , metallurgy
Abstract Magnetic collection of the microalgae Chlorella sp. from culture media facilitated by low‐gradient magnetophoretic separation is achieved in real time. A removal efficiency as high as 99% is accomplished by binding of iron oxide nanoparticles (NPs) to microalgal cells in the presence of the cationic polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) as a binder and subsequently subjecting the mixture to a NdFeB permanent magnet with surface magnetic field ≈6000 G and magnetic field gradient <80 T m −1 . Surface functionalization of magnetic NPs with PDDA before exposure to Chlorella sp. is proven to be more effective in promoting higher magnetophoretic removal efficiency than the conventional procedure, in which premixing of microalgal cells with binder is carried out before the addition of NPs. Rodlike NPs are a superior candidate for enhancing the magnetophoretic separation compared to spherical NPs due to their stable magnetic moment that originates from shape anisotropy and the tendency to form large NP aggregates. Cell chaining is observed for nanorod‐tagged Chlorella sp. which eventually fosters the formation of elongated cell clusters.