386-2 Transformations of ZnO Nanoparticles in Waste Water Treatment, Biosolids and Soil.
Poster Number 1114
See more from this Division: S02 Soil ChemistrySee more from this Session: Natural and Synthetic Nanoparticles in Terrestrial and Aquatic Ecosystems: II
ZnO MNMs will likely react with both phosphate ions and natural organic matter (NOM) in the wastewater stream and in the wastewater treatment process. Although the solubility of Zn-phosphates are low (Ksp ~9X 10-33), little is known regarding the reaction kinetics of ZnO MNMs with phosphate, NOM, and in mixed phosphate-NOM systems. To address this critical knowledge gap, we examined the transformation reactions of 30nm ZnO MNMs in the presence of phosphate and NOM as a function of time and pH. Samples were analyzed using various techniques, including dynamic light scattering, phase analysis light scattering, inductively coupled plasma mass spectrometry, spatially resolved synchrotron X-ray absorption near edge structure spectroscopy, Phosphorus-31 nuclear magnetic resonance spectroscopy, as well as transmission electron microscopy coupled with energy dispersive x-ray spectroscopy. Preliminary data reveals that ZnO MNMs react with phosphate at concentrations expected in wastewater and transform into two distinct phases; a micron sized zinc phosphate mineral phase (hopeite) and a nano-sized phosphate rich ZnO phase. TEM imaging with energy dispersive X-ray spectroscopy and XANES spectroscopy provide evidence that the nano- sized phosphate rich ZnO phase is likely comprised of a ZnO core and a Zn-phosphate shell.
See more from this Session: Natural and Synthetic Nanoparticles in Terrestrial and Aquatic Ecosystems: II