Kinetics of early nucleation and growth of iron oxide nanoparticles at mineral-water interfaces

COLL 270

Young-Shin Jun, ysjun@seas.wustl.edu, Energy, Environmental and Chemical Engineering, Washington University, One Brookings Drive, St. Louis, MO 63130-4899, Glenn A. Waychunas, gawaychunas@lbl.gov, Earth Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 70-0120, Berkeley, CA 94720, and Byeongdu Lee, blee@aps.anl.gov, X-ray Science Division, Argonne National Laboratory, Building 433E006, 9700 South Cass Avenue, Argonne, IL 60439.
The nucleation and growth of iron oxide nanoparticles on mineral surfaces can drastically affect metal contaminant transport and other surface-controlled reactions. However, there has been no in situ kinetic study of the early nucleation and growth of iron oxide nanoparticles in aqueous systems as soft nuclei are difficult to observe without major disruption.

In this work, we devised the first environmental application of grazing-incidence small angle X-ray scattering (GISAXS) in aqueous systems and studied the kinetics of early nucleation and growth of iron oxide nanoparticles at water-quartz interfaces. The changes in the sizes and shapes of nuclei and the interspacing between nuclei on quartz surfaces are determined as a function of reaction time. The iron oxide nuclei start to grow near steps rather than on terraces.

GISAXS allows statistically improved morphological information about interfacial reactions to be obtained in real-time, and enables kinetics analysis of nanoparticle formation at environmental interfaces.

 

The Physical Chemistry of Environmental Interfaces
6:00 PM-8:00 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 244/245, Poster

Division of Colloid & Surface Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008