TY - JOUR
T1 - Heteroaggregation between PEI-coated magnetic nanoparticles and algae
T2 - Effect of particle size on algal harvesting efficiency
AU - Ge, Shijian
AU - Agbakpe, Michael
AU - Zhang, Wen
AU - Kuang, Liyuan
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/3/25
Y1 - 2015/3/25
N2 - Colloidal interactions between magnetic nanoparticles (NPs) and algal cells are of paramount significance to magnetophoretic separation of algal biomass from water. This study evaluated the size effect of magnetic NPs (MNPs) coated with polyethylenimine (PEI) on the separation efficiency of Scenedesmus dimorphus as well as on the recovery efficiency of MNPs from algal biomass. Results showed that algal harvesting efficiency (HE) increased from ca. 60% to 85% as the diameter of PEI-coated MNPs increased from 9 to 53 nm. Likewise, algal recovery capacity (algae/MNPs, w/w) also showed the same size dependence. But a large size (247 nm) led to a decline of algal HE, which was correctly interpreted by a settling model that predicts large sizes of MNPs could eventually reduce the settling velocity under magnetophoresis. The extended Derjaguin-Landau-Verwey-Overbeek theory revealed that the particle size and PEI coating both influenced the interaction energies (e.g., energy barrier) between MNPs and algae. Particularly, PEI coating significantly reduced the energy barrier between MNPs and algae and thereby increased their heteroaggregation and algal HE. Moreover, PEI-coated MNPs were recovered from the harvested algae biomass through a chemical-free ultrasonic method, and the recovery efficiency appeared to be higher for larger MNPs. Overall, the synthesized sizes of applied MNPs will not only affect algal HE but also have economic implications on magnetophoretic algal separation technologies.
AB - Colloidal interactions between magnetic nanoparticles (NPs) and algal cells are of paramount significance to magnetophoretic separation of algal biomass from water. This study evaluated the size effect of magnetic NPs (MNPs) coated with polyethylenimine (PEI) on the separation efficiency of Scenedesmus dimorphus as well as on the recovery efficiency of MNPs from algal biomass. Results showed that algal harvesting efficiency (HE) increased from ca. 60% to 85% as the diameter of PEI-coated MNPs increased from 9 to 53 nm. Likewise, algal recovery capacity (algae/MNPs, w/w) also showed the same size dependence. But a large size (247 nm) led to a decline of algal HE, which was correctly interpreted by a settling model that predicts large sizes of MNPs could eventually reduce the settling velocity under magnetophoresis. The extended Derjaguin-Landau-Verwey-Overbeek theory revealed that the particle size and PEI coating both influenced the interaction energies (e.g., energy barrier) between MNPs and algae. Particularly, PEI coating significantly reduced the energy barrier between MNPs and algae and thereby increased their heteroaggregation and algal HE. Moreover, PEI-coated MNPs were recovered from the harvested algae biomass through a chemical-free ultrasonic method, and the recovery efficiency appeared to be higher for larger MNPs. Overall, the synthesized sizes of applied MNPs will not only affect algal HE but also have economic implications on magnetophoretic algal separation technologies.
KW - EDLVO
KW - algae
KW - biofuel
KW - harvesting
KW - magnetic nanoparticles
KW - magnetophoretic separation
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U2 - 10.1021/acsami.5b00572
DO - 10.1021/acsami.5b00572
M3 - Article
C2 - 25738208
AN - SCOPUS:84925763540
SN - 1944-8244
VL - 7
SP - 6102
EP - 6108
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 11
ER -