Suppression of pyrite oxidation by lipid coating: Kinetics, mechanism, surface structures, and implications in acid mine drainage

COLL 516

Xiang V. Zhang, xzhang@deas.harvard.edu1, Treavor A. Kendall, tkendall@deas.harvard.edu2, Daniel R. Strongin, dstrongi@temple.edu3, Martin Schoonen, martin.schoonen@sunysb.edu4, and Scot Martin, smartin@deas.harvard.edu2. (1) Division of Engineering and Applied Sciences, Harvard University, 40 Oxford St., Cambridge, MA 02138, (2) School of Engineering and Applied Sciences, Harvard University, 40 Oxford St., Cambridge, MA 02138, (3) Department of Chemistry, Temple University, 1901 N. 13th St, Philadelphia, PA 19122, (4) Department of Geosciences, Stony Brook University, Stony Brook, NY 11794-2100
Pyrite (FeS2) oxidation in nature has severe environmental implications such as acid mine drainage. The adsorption of lipids on pyrite surface has been found to be an effective way to suppress the oxidation chemistry. The effectiveness depends on the chain length of the hydrocarbon tail of the lipids. Surface vibrational spectroscopy shows the electrostatic interaction between lipids and pyrite surface. Surface structures of the lipid layer on the pyrite are observed by atomic force microscopy (AFM). Lipid forms bilayer structure on pyrite surface. This bilayer structure creates a hydrophobic “blanket” on the surface, isolating the pyrite from oxidants such as water and Fe3+ ions. Through surface spectroscopic and microscopic studies, we are able to develop a mechanistic understanding of the suppression of pyrite oxidation by lipid coating.
 

Environmental Interfaces
2:00 PM-5:50 PM, Wednesday, 13 September 2006 Sir Francis Drake -- Empire Room, Oral

Division of Colloid & Surface Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006