UC Riverside

The primary goals of this doctoral research were to investigate aqueous solution parameters that may affect the aggregation behavior of engineered nanomaterials (ENMs), increase the analytical capacity of the colloidal research community, and explore ways in which scientists and engineers can collaborate across disciplines in ways that make individual efforts more robust and more amenable to positive societal contributions. Studies with ENMs were conducted with materials ranging from established, widespread titanium dioxide, to unique, niche graphene oxide and molybdenum disulfide, to emerging, nascent few-layered black phosphorus. The effects of environmentally relevant parameters (i.e., pH, ionic strength, cation valence, extracellular polymeric substances, surfactants, and coagulant) on the electrokinetic properties, aggregation rates, and/or aggregation morphology of the ENMs were investigated.

The following valuable insights were obtained from this dissertation research. The 2D black phosphorus ENMs investigated were found to be colloidally stable in environmental conditions. This insight could be used to further develop BP towards future biomedical and environmental applications. In addition, this investigation demonstrated the validity of using traditional colloidal characterization techniques on non-spherical, two-dimensional ENMs. Results from this work could lead to further research into the stability of other 2D ENMs, improving the collective scientific knowledge, and leading to further, novel applications of these versatile ENMs. A further aim of this research was to identify effects of specific environmental parameters on titanium dioxide nanoparticles. The resultant information can be used to better predict the fate and transport of this common ENM in complex environments. The final objective of this doctoral research, to lessen the divide between the academic research community and policymakers, was achieved by applying technical expertise and scientific principles to two distinct challenges; the correlation of personality to drinking water preferences and the synthesis of best practices for state-level water data management. This dissertation provides critical understanding of fundamental aggregation behavior of various ENMs and demonstrates the value of extending the tools of the scientific enterprise across disciplinary boundaries and beyond the ivory tower of academia.