Magnetite nanocrystals have broad potential for application(s) in environmental technologies due to their tunable size and physicochemical properties. Material size (control) and surface chemistry are crucial for successful application, especially in saturated, porous (media) matrixes with various ionic strengths and redox chemistries. Here, we describe monodisperse magnetite nanocrystals (8 to 30 nm) prepared and subsequently transferred into water through a variety of surface modification techniques. Stability experiments under varied ionic strengths and compositions indicate that aggregation kinetics are strongly dependent on the electrolyte concentrations, cation types, and surface chemistries. In addition, we describe how environmental aging (via oxidation) of surface coatings affects stabilities, leading to varied mobility and retention behaviors. Quartz crystal microbalance with dissipation monitoring (QCM-D) was used to investigate the particle-surface interactions using hydrophilic (SiO2) and hydrophobic (polystyrene) sensors. Varied surface coatings, degree of aging and the solution chemistry directly influence deposition behavior.

Effects of surface chemistries and environmental aging on the aggregation and deposition behaviors of engineered magnetite nanocrystals in aquatic systems

245th National Meeting (2013)

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