| Increasing use of engineered nanomaterials presents concerns as some nanoparticles appear to be harmful to both human health and the environment. Effective treatment methods are required to remove problematic nanoparticles from (waste)water streams. Porous media filtration, commonly used for the removal of particulate matter, shows promise for nanoparticle treatment. The goal of this work is to investigate the potential of porous media filtration for the abatement of nanoparticles from aqueous waste streams. To this end, an automated method was developed that allows real-time and in-situ monitoring of nanoparticle transport and retention in porous media using online measurement of UV-visible absorbance or fluorescence.;Development of fluorescent-core nano-silica (n-SiO2) in controllable sizes provided an excellent tracer for nanoparticle transport in porous media. Measurement of n-SiO2 by destructive techniques is complicated by high natural Si background levels. Fluorescence monitoring enables real-time measurement, facilitating rapid evaluation of n-SiO2 transport. Synthesized n-SiO2 remain in their primary sizes making an evaluation of the behavioral change of particles due to transition into the “nano” range possible. A comparison of the role of particle size on transport in porous media displayed the importance of particle number concentration as the dominance of site-specific adsorption may be obscured by simple mass concentration evaluation.;The effectiveness of different bed materials, namely, sand, activated carbon (AC), and diatomaceous earth (DE), for the removal of TiO2 nanoparticles (n-TiO2) from aqueous streams was investigated. DE proved promising for n-TiO2 capture shown by its 18 high bed capacity (33.8 mg TiO2 g-1 medium) compared to AC (0.23 mg TiO2 g-1 medium) or sand (0.004 mg TiO2 g-1 medium). The presence of organic and synthetic contaminants produced varying effects on n-TiO2 retention, mostly due to either enhanced electrostatic or steric interactions.;Application of a process simulator combining physical straining with site-specific interactions, delineating physisorption from chemisorption and diffusion limited interactions, enabled the accurate fit of n-TiO2 transport in sand, AC and DE. The fitting process revealed the advantage of DE due to increased physisorption and physical straining of n-TiO2. Modeling of this system afforded the elucidation of controlling retention mechanisms and provides a basis for future scaling and system design. |
