Effects of underlying minerals on sorption/desorption of phenanthrene to organic matter

GEOC 31

Thomas M. Young, tyoung@ucdavis.edu, Department of Civil and Environmental Engineering, University of California, Davis, One Shields Ave., Davis, CA 95616 and Naoko Watanabe, naowatanabe@ucdavis.edu, Department of Land, Air and Water Resources, University of California at Davis, One Shields Ave., Davis, CA 95616.
Mineral-organic matter (OM) complexes were prepared to study the effects of minerals on hydrophobic organic contaminant sorption/desorption behaviors. The reactivity of the mineral phase was hypothesized to influence the configuration and accessibility of OM domains, in addition to differences in OM qualities selectively sorbed to different minerals, and as a result elevate sorption capacities and/or imparts desorption resistance. Montmorillonite, halloysite and synthesized aluminum oxide were coated with Leonardite Humic Acid Standard (HA). The differences in OM qualities were characterized using quantitative pyrolysis GC-MS and solid state 13C NMR. 1H T2 relaxation times were also measured. Different pyrolysis and NMR results indicate that the different minerals selectively sorb OM through different interaction mechanisms. Slightly higher organic carbon normalized distribution coefficient (KOC) and hysteresis index (HI) values for HA-montmorillonite and HA-halloysite complexes and a significantly lower KOC and higher HI values for HA-Al oxide complex were observed compared with HA without minerals.
 

Physical Chemistry of Soil and Aquifer Systems: A Symposium in Honor of Garrison Sposito
1:30 PM-5:10 PM, Sunday, 10 September 2006 Moscone Center -- Room 256, Oral

Division of Geochemistry

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