The fate, transport, and toxicity of human engineered nanomaterials released into in the environment, especially into wastewater treatment and surface and groundwater systems is a topic of great societal and scientific importance. The funded project is a systematic investigation of the physicochemical interactions between nanomaterials and the environment. Its goal is to assess the effectiveness of conventional wastewater treatment processes in trapping and/or removing common human-engineered nanoparticles from domestic water supplies. The work involves extensive nanoparticle characterization and transport experiments under environmentally relevant conditions. The behavior and interaction of three categories of nanoparticles will be examined: metal oxides (hematite, titanium oxide, cerium oxide, zinc oxide), metal (gold), and carbon-based (carbon nanotubes). The impact of various coating/capping agents such as Dextran, DMSA, and Polyamiline that are commonly used on these particles will also be examined. Both bare and coated/capped nanoparticles will be tested. Their stability, reactivity, and the effectiveness of removal will be evaluated at each of the four stages of water treatment: coagulation, flocculation, sedimentation, and filtration. Nanomaterial behavior over a wide range of water quality parameters, from simplified electrolytes to complex solution chemistries will be examined. Filtration mechanisms will also be investigated in microscopic and macroscopic flow systems. The impacts of nanoparticle characteristics such as electrophoretic mobility, hydrophobicity, crystalline structure, concentration, and size and shape on the efficiency and effectiveness of wastewater treatment processes will be examined using transmission electron microscopy, UV/Vis, time-resolved dynamic light scattering, fluorescent labeling, magnetic saturation, and other methods. Experiments will take place in packed bed columns and micromodel systems. Broader impacts of the research include improving our knowledge of nanoparticle transport and their trapping and removal from drinking water. The work supports an early career PI whose gender is underrepresented in the sciences and engineering, will engage Hispanic undergraduates from a local community college, and will be incorporated into undergraduate courses. The work will also partner K12 teachers and students at the Riverside Unified School District with university students through the preparation of materials on how to develop science faire projects on water quality.
