Multiwalled carbon nanotube dispersion methods affect their aggregation, deposition, and biomarker response.
To systematically evaluate how dispersion methods affect the environmental behaviors of multiwalled carbon nanotubes (MWNTs), MWNTs were dispersed in various solutions (e.g., surfactants, natural organic matter (NOM), and etc.) via ultrasonication (SON) and long-term stirring (LT). The two tested surfactants [anionic sodium dodecyl sulfate (SDS) and nonionic poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEO-PPO-PEO) triblock copolymers (Pluronic)] could only disperse MWNTs via ultrasonication; while stable aqueous SON/MWNT and LT/MWNT suspensions were formed in the presence of the two model NOMs (Suwannee river humic acid and fulvic acid). Due to the inherent stochastic nature for both methods, the formed MWNT suspensions were highly heterogeneous. Their physicochemical properties, including surface charge, size, and morphology, greatly depended upon the dispersant type and concentration but were not very sensitive to the preparation methods. Aggregation and deposition behaviors of the dispersed MWNTs were controlled by van der Waal and electrostatic forces, as well as other non-DLVO forces (e.g., steric, hydrophobic forces, etc.). Unlike the preparation method-independent physicochemical properties, LT/NOM-MWNTs and SON/NOM-MWNTs differed in their fathead minnow epithelial cell metabolomics profiles.
†National Research Council, National Academy of Science, 2101 Constitution Avenue Northwest, Washington, DC 20418, United States.
Xiaojun
X
Chang
‡USEPA Office of Research and Development, National Exposure Research Laboratory, 960 College Station Road, Athens, Georgia 30605, United States.
W Matthew
WM
Henderson
‡USEPA Office of Research and Development, National Exposure Research Laboratory, 960 College Station Road, Athens, Georgia 30605, United States.
Dermont C
DC
Bouchard
D000818:Animals; D015415:Biomarkers / Q000032:analysis* / Q000378:metabolism; D002478:Cells, Cultured; D003530:Cyprinidae / Q000378:metabolism; D054750:Ecotoxicology / Q000379:methods; D006812:Humic Substances; D057927:Hydrophobic and Hydrophilic Interactions; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000633:toxicity*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D011409:Propylene Glycols / Q000737:chemistry; D045483:Rivers / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D055672:Static Electricity; D013501:Surface-Active Agents / Q000737:chemistry; D014867:Water; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
D015415:Biomarkers; D006812:Humic Substances; D037742:Nanotubes, Carbon; C116176:PEO-PPO-PEO; D011409:Propylene Glycols; D012996:Solutions; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; D014867:Water; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols