Engineered nanoparticles (ENPs) are likely to be vastly outnumbered by naturally occurring colloids in aquatic systems.  As such, interactions between ENPs and natural colloids (heteroaggregation) are likely to dominate over homoaggregation.  Relatively little is known about heteroaggregation processes, making it difficult to predict environmental transport and fate in complex aquatic systems.  We will discuss our work quantifying the association of citrate-capped gold nanoparticles (AuNPs) with hematite and silica colloids in suspensions of varying pH and ionic strength.  We also anticipate being able to present preliminary results examining the role of nanoparticle capping agent on these processes.  EPA test waters of varying hardness were used as suspending media and the effect of added Suwannee River Natural Organic Matter was evaluated.  In addition to tracking changes in aggregate size using dynamic light scattering, attachment of the AuNPs with the model colloids was quantified by membrane size fractionation followed by ICP analysis.

Heteroaggregation between gold nanoparticles and metal oxide colloids: Effects of colloid type and aquatic chemistry

248th National Meeting (2014)

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