Thursday, November 8, 2007 - 9:00 AM
342-3

Zinc Oxides Nanoparticles Interactions with Clay Minerals: Sorption Behavior.

Nadine J. Kabengi1, John Seaman2, Jonathan Judy1, and Paul Bertsch2. (1) Univ. of Georgia, Savannah River Ecology Laboratory, P.O.Box Drawer E, Aiken, SC 29802-1030, (2) PO Box E, University of Georgia, Univ. of Georgia, Savannah River Ecology Lab, Aiken, SC 29802-1030

Zinc oxides nanoparticles (ZnO-np) growing production and utilization will lead to their introduction to soil environments. ZnO-np interactions with clay minerals may have a dominant role in regulating their mobility as well as their potential impacts on biogeochemical processes. This study investigated the sorption behavior of manufactured ZnO-np on a Montmorillonite (Swy-2, Wyoming USA) as referenced against an equivalent concentration of aqueous Zn2+. Batch sorption experiments were conducted as a function of clay form (parent material and fine fraction), clay amounts (0.25-0.5 g) and initial Zn concentrations (50-200 mg.L-1). Both DDI water and 0.05 M CaCl2 were tested for their ability to desorb sorbed ZnO-np. Additionally, two different types of cation exchange resins (weakly and strongly acidic) were tested for their interactions with both ZnO-np and ZnCl2. ZnO-np exhibited a sorption behavior similar to that of a solvated divalent cation held on exchange sites. Nonetheless X-ray powder diffraction results yielded evidence for clay interlayer expansion in presence of ZnO-np with d-spacings around 15.185Å as compared to 14.367Å with aqueous ZnCl2.