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Filley

Tim Filley
Associate Professor
filley@purdue.edu

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Dept of Earth & Atmospheric Sciences
Purdue University
550 Stadium Mall Drive
West Lafayette, IN 47907
ph. (765) 494-6581

Environmental Chemistry

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We use a biogeochemical perspective to investigate how emerging pollutants respond in the natural environment. We attempt to show couples effects of microbial and photochemical decomposition impact the environmental fate of commercial chemicals that are or are projected to be accumulating in our sediments and soils. We combine microcosm and laboratory experiments to observe how microbes and minerals change the chemical form of these pollutants and, potentially, alter the rate at which they cycle in natural settings and make their way into living and nonliving reservoirs. Our projects have focused on brominated flame retardants (Ahn et al., 2006a; Ahn et al., 2006b; Tokarz et al., 2008) and, most recently, microbial response to manufactured nanocarbon materials such as C60, fullerols and carbon nanotubes ( Schreiner et al., 2009).

Consider: Schreiner, K.M., T.R. Filley, R.A. Blanchette, B.B. Bowen, R. D. Bolskar (2009) White-Rot Basidiomycete-mediated Decomposition of C60 Fullerol, Environmental Science and Technology doi: 10.1021/es801873q.



Industrially produced carbon-based nanomaterials (CNM), including fullerenes and nanotubes, will be introduced into the environment in increasing amounts in the next decades. One likely environmental chemical transformation of C60 is oxidation to C60 fullerol through both abiotic- and biotic-mediated means. Unfortunately, knowledge of the environmental fate of oxidized CNM is lacking. This study used bulk and compound specific 13C stable isotope ratio mass spectrometry techniques and spectroradiometry analysis to examine the ability of two white rot basidiomycete fungi (Phlebia tremellosa and Trametes versicolor) to metabolize and degrade an oxygenated CNM, C60 fullerol.



After 32 weeks of decay, both fungi were able to bleach and oxidize fullerol to CO2. Additionally, the fungi incorporated minor amounts of the fullerol carbon into lipid biomass. These findings are significant in that they represent the first report of direct biodegradation and utilization of any fullerene derivative and provide valuable information about the possible environmental fates of other CNM.

New Research: Collaborators Chad Javert (Purdue) and Howard Fairbrother (Johns Hopkins University)
In a recently funded EPA STAR grant we investigate how photochemical oxidation chemically "primes" carbon nanotubes (CNTs) for further microbial decomposition. The transformations of CNTs in the environment are likely to be dominated by abiotic oxidative and extracellular microbial processes. Consequently, we propose to study photochemical and fungal mediated transformations that occur to colloidal and solid phase CNTs, including CNTs immobilized in polymer composites. We plan to identify transformation products, reaction kinetics, and reaction mechanisms, including the effects of coupled photochemical-fungal exposures. For CNT-polymer composites, we will study transformations of the composites, and determine if and under what conditions CNTs are released from composites as a result of exposure to light and/or fungi. The capacity of fungi to use CNTs as a carbon source for metabolism and growth will also be investigated. Our objectives are based on two overarching hypotheses: (i) Photochemical and fungal transformations of CNTs will occur and proceed via oxidative processes with important consequences for their overall persistence in the environment, and (ii) that the rate of these reactions will depend on CNT physicochemical properties (e.g. surface properties), environmental conditions (e.g. pH, fungi type), and CNT form (e.g. colloids or immobilized in polymers).