Attachment of engineered nanoparticles to natural organic matter (NOM) is expected to influence their transport and fate in the environment and influence their bioavailability to organisms. Using a novel citric acid derivative, organic ligands were anchored to TiO2 nanoparticles using azide-terminated polyethylene glycol (PEG) molecules presenting different head groups to solution. The functionalized nanoparticles were characterized by dynamic light scattering, transmission electron microscopy, and infrared and X-ray photoelectron spectroscopy. To examine nanoparticle attachment to humic substances we electrostatically assembled nanoscale films of Elliot soil humic acid on quartz crystal microbalance with dissipation monitoring (QCM-D) and optical waveguide lightmode spectroscopy (OWLS) sensors. We examined nanoparticle attachment over a range of environmentally relevant solution conditions (pH 5-8 and ionic strength = 5-50 mM. Final adsorbed masses, attachment rate constants, attachment efficiencies, and water content (determined through parallel QCM-D and OWLS experiments) were determined.

Kinetics of modularly functionalized anatase nanoparticle attachment to humic acids

243rd National Meeting (2012)

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