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Dr. Ahn specializes in the transport and fate of hydrophobic organic contaminants including PAHs, PCBs, and polybrominated diphenyl ethers (PBDEs), and their bioavailability. Dr. Ahn also has expertise in the environmental behavior of nanomaterials. He is knowledgeable in the use of a variety of laboratory analytical methods including gas chromatography (GC) and mass spectrometry (GC/MS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD). Before joining Exponent, Dr. Ahn worked as a postdoctoral scholar at Stanford University, where he conducted research on the degradation of flame retardant PBDEs by various forms of nano-scale zerovalent iron (nZVI). Dr. Ahn studied the reaction kinetics and the degradation pathways of PBDEs with positional preference in the debromination. As a part of the research, he synthesized the nanoparticle, as well as its catalyzed and carbon supported particles, in the laboratory and characterized them using analytical tools such as TEM, SEM, XPS, and XRD. During his Ph.D. work, Dr. Ahn studied the transport and fate of PAHs in contaminated soil and sediment amended with a carbon sorbents for in situ contaminant stabilization. The study included physicochemical characterization of contamination at the micro-scale for source identification, assessment of PAH bioavailability and availability to the surroundings, and model simulation of contaminant mass transfer in sediment-sorbent systems, to predict the fate of PAHs and the long-term effect of carbon amendment. In addition, he also has extensive field and laboratory experience in in situ stabilization of PCBs in contaminated sediment using carbon amendment.
Ahn S, Werner D, Luthy RG. Modeling PAH mass transfer in a slurry of contaminated soil or sediment amended with organic sorbents. Water Research 2008; 42:2931–2942.
Yoon TH, Benzerara K, Ahn S, Luthy RG, Tyliszczak T, Brown GE. Nanometer-scale chemical heterogeneities of black carbon materials and their impacts on PCB sorption properties: Soft x-ray spectromicroscopy study. Environmental Science and Technology 2006; 40:5923–5929.
Ahn S, Werner D, Karapanagioti HK, McGlothlin DR, Zare RN, Luthy RG. Phenanthrene and pyrene sorption and intraparticle diffusion in polyoxymethylene, coke, and activated carbon. Environmental Science and Technology 2005; 39:6516–6526.
Ahn S, Werner D, Luthy RG. Physicochemical characterization of coke-plant soil for the assessment of polycyclic aromatic hydrocarbon availability and the feasibility of phytoremediation. Environmental Toxicology and Chemistry 2005; 24:2185–2195.
Presentations
Zhuang Y, Ahn S, Luthy RG. Debromination of polybrominated diphenyl ethers by nano-iron particles and carbon-supported nano-iron particles. 239th American Chemical Society National Meeting, San Francisco, CA, March 2010.
Zhuang Y, Ahn S, Luthy RG. PBDE debromintaion by nano-scale zerovalent iron (nZVI) and carbon supported nZVI. SETAC North America Annual Meeting, New Orleans, LA, November 2009.
Yoon TH Benzerara K, Ahn S, Luthy RG, Tyliszczak T, Brown GE. Soft x-ray spectromicroscopy study of carbonaceous materials: Characterization of their chemical heterogeneities in sub-micrometer scale. 229th American Chemical Society National Meeting, San Diego, CA. March 2005.
- Postdoctoral Scholar, Stanford University, 2006–2010
- American Chemical Society
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- Ph.D., Civil and Environmental Engineering, Stanford University, 2006
- M.S., Civil and Environmental Engineering, Stanford University, 2001
- M.S., Chemical Engineering, Yonsei University, South Korea, 1997
- B.S., Chemical Engineering, Yonsei University, South Korea, 1995
- The Ford Fund Fellowship, 2001–2003
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