Page 246 - Environmental Nanotechnology Applications and Impacts of Nanomaterials

Chapter
7

Nanoparticle Transport,

Aggregation, and Deposition

Jonathan Brant Duke University, Durham, North Carolina, USA
Jérôme Labille CNRS-Université Aix-Marseille, Aix-en-Provence, France
Jean-Yves Bottero CNRS-Université Aix-Marseille, Aix-en-Provence, France
Mark R. Wiesner Duke University, Durham, North Carolina, USA

Introduction
This chapter explores physical-chemical factors that govern two key
processes controlling the transport and fate of nanomaterials in aquatic
environmental systems, aggregation and deposition. There is a well-
developed body of work addressing the behavior of particles in water.
In particular, we consider applications of the principles of colloid chem-
istry to specific nanomaterials and possible insights that theory provides
for the case of very small colloidal particles. However, the format of
nanomaterials that is environmentally relevant (e.g., as pure materials
versus composites), the quantities and concentrations likely to be pres-
ent, and the patterns of production, use, and disposal are, at the time
of writing, largely speculative.
Particle aggregation and deposition can be thought of as occurring in two
steps. First, particles are transported to the vicinity of a surface and then,
if conditions allow, particles attach to the surface. In aggregation, the sur-
face may be that of another particle or a growing aggregate. In deposition,
the surface is an immobile “collector” where particles accumulate. Much
of this chapter addresses the role of surface chemistry and associated
interfacial relationships, as they affect the attachment step and ultimately
nanoparticle mobility in aquatic environments. Basic concepts from colloid

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