R1 PM Nanotechnology Environmental Remediation, Fate, and Transport
Thursday, 17 November 2005: 1:50 PM - 5:30 PM in Ballroom 1

(FOR-1117-852532) Reactivity of Water-Stable C₆₀ Aggregates During Ozonation and UV Irradiation Processes.

Fortner, John¹, Kim, Doo-Il¹, Kim, Jae-Hong ¹, Hughes, Joseph¹, ¹ Georgia Institute of Technology, School of Civil & Environmental Engineering, Atlanta, Georgia, USA

ABSTRACT- As industrial scale production of nanomaterials becomes a reality, little is known about the unintentional impact on natural systems, particularly with regard to water quality. Current regulation of carbon fullerenes highlights this fact as the Occupational Safety and Health Administration (OSHA, U.S. Department of Labor) guidelines for handling and disposal is to simply follow the material safety data sheet (MSDS) for carbon black. However, fullerenes do not behave in such an analogous fashion as they can form discrete aggregates on the nano-scale that remain as a stable suspension in water over time. Such behavior, coupled with recent findings that these aggregates interact with living cells, underlines the need to understand the fate and the transformation of carbon fullerenes during engineered water treatment processes, particularly with regard to potable water. Research presented herein investigates the stability, transformation kinetics and reaction products of fullerene (as C₆₀) aggregates (termed nano-C₆₀) during ozonation and UV irradiation, common water treatment processes. For both processes, semi-batch and batch experiments, a matrix of variables was examined including pH (5-9), temperature (5-30 C) and aggregate size. Preliminary semi-batch ozonation results suggest that the half life of nano-C₆₀ at representative experimental conditions tested ([O₃]₀ = 2.8 mg/L, 5mg/L nano-C₆₀, buffered) was approximately 24 min. UV/Vis spectral changes over time, particularly the loss of characteristic C₆₀ absorbance peaks at 450, 340, 260 nm, indicated that the fullerene carbon cage had been altered. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) data indicate the loss of aggregate size and integrity, further suggesting soluble product(s). Ongoing product characterization using 13C-NMR and mass spectroscopy will be presented along with the results from parallel UV irradiation experiments.

Key words: water treatment, fullerene chemistry, nano waste