Applications and physicochemical characterization of nanomaterials in environmental, health, and safety studies

As commercially manufactured nanomaterials become more commonplace, they have the potential to enter ecological and biological environments during their lifecycle of production, distribution, use or disposal. Despite rapid advances in the production and application of nanomaterials, little is known about how they may interact with the environment or affect human health. This research investigates an environmental application of nanomaterials and characterizes physicochemical properties of commonly manufactured nanomaterials in environmental, health, and safety studies.;Characterization of nanomaterials for applications and environmental health and safety studies is essential in order to understand how physicochemical properties correlate with chemical, ecological, or biological response or lack of response. Full characterization includes determining the bulk (shape, size, phase, electronic structure and crystallinity) and surface (surface area, arrangement of surface atoms, surface electronic structure, surface composition and functionality) properties of nanomaterials.;This work investigates the selective catalytic reduction (SCR) of NO 2 to N2 and O2 with ammonia on nanocrystalline NaY, Aldrich NaY and nanocrystalline CuY using in situ Fourier transform infrared (FTIR) spectroscopy. The kinetics of SCR were 30% faster on nanocrystalline NaY compared to commercial NaY due to an increase in external surface area and external surface reactivity. Nanocrystalline CuY showed an additional increase in the rate of SCR as well as distinct NO2 and NH 3 adsorption sites associated with the copper cation. These superior de-NOx materials could contribute to a cleaner environment.;This work consists of characterization of commonly manufactured or synthesized nanomaterials and studies of nanomaterials in specific environmental conditions. Bulk and surface characterization techniques were used to examine carbon nanotubes, titanium dioxide nanoparticles, bare silver nanoparticles and polymer-coated silver nanoparticles, and copper nanoparticles. Lithium titanate nanomaterial collected from a manufacturing facility was also characterized to identify occupational health risks. Particle size distribution measurements and chemical composition data showed the lithium titanate nanomaterial forms larger micrometer agglomerates, while the nanoparticles present were due to incidental processes.;A unique approach was applied to study particle size during dissolution of nanoparticles in aqueous and acidic conditions. An electrospray coupled to a scanning mobility particle sizer (ES-SMPS) was used to determine the particle size distribution of bare silver nanoparticles in nitric acid and copper nanoparticles in hydrochloric acid. The results showed size-dependent dissolution behavior. Size-dependent properties of nanomaterials may influence transport and transformation, and the behavior of larger sized materials cannot be used to predict nanomaterial behavior. The type of nanomaterial and the media it enters are important factors for determining the fate of the nanomaterial. These studies will be important when considering measures for exposure control and environmental remediation of nanomaterials.