Stability and aggregation of metal oxide nanoparticles in natural aqueous matrices.
There is a pressing need for information on the mobility of nanoparticles in the complex aqueous matrices found in realistic environmental conditions. We dispersed three different metal oxide nanoparticles (TiO(2), ZnO and CeO(2)) in samples taken from eight different aqueous media associated with seawater, lagoon, river, and groundwater, and measured their electrophoretic mobility, state of aggregation, and rate of sedimentation. The electrophoretic mobility of the particles in a given aqueous media was dominated by the presence of natural organic matter (NOM) and ionic strength, and independent of pH. NOM adsorbed onto these nanoparticles significantly reduces their aggregation, stabilizing them under many conditions. The transition from reaction to diffusion limited aggregation occurs at an electrophoretic mobility from around -2 to -0.8 microm s(-1) V(-1) cm. These results are key for designing and interpreting nanoparticle ecotoxicity studies in various environmental conditions.
University of California, Santa Barbara, USA. keller@bren.ucsb.edu
Arturo A
AA
Keller
Hongtao
H
Wang
Dongxu
D
Zhou
Hunter S
HS
Lenihan
Gary
G
Cherr
Bradley J
BJ
Cardinale
Robert
R
Miller
Zhaoxia
Z
Ji
D002563:Cerium / Q000032:analysis / Q000737:chemistry*; D005618:Fresh Water / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry; D053768:Metal Nanoparticles / Q000032:analysis / Q000737:chemistry*; D010316:Particle Size; D012623:Seawater / Q000737:chemistry; D014025:Titanium / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D015034:Zinc Oxide / Q000032:analysis / Q000737:chemistry*
D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D002563:Cerium; C030583:ceric oxide; D014025:Titanium; D015034:Zinc Oxide