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PREFERENTIAL PARTITIONING OF PAHS AND PCBS TO COAL FLY ASH
Citation:
Burgess, R M., S A. Ryba, M G. Cantwell, R Tien, R. A. Wassel, AND K. Gwei. PREFERENTIAL PARTITIONING OF PAHS AND PCBS TO COAL FLY ASH. Presented at The Society of Environmental Toxicology & Chemistry Annual Meeting, Nashville, TN, November 12-16, 2000.
Description:
It has long been known that fly ash has a significant capacity for the adsorption of several classes of anthropogenic pollutants, including toxic metals, nutrients and organic compounds. This adsorption capacity has been utilized by wastewater treatment plants for the removal of contaminants from sludge and waste water. Given the ability of fly ash to sequester contaminants in complex media (e.g. sediments), it has potential for use in performing toxicity characterizations. In this study, we examined the interaction of several fly ashes with ten PAHs and PCBs (including three planar PCBs). Specifically, we investigated how fly ash compared as a sorbent relative to other organic carbon matrices and effect of the solvent system on its absorption capacity. Batch studies were conducted with coal-fired power plant fly ash and contaminant additions. Following a 48 hour equilibration period with vigorous mixing, the solvent system was physically separated from the fly ash, analyzed for PAHs and PCBs with GC and GC-MS, and the measured .concentrations compared to a blank. Solvent systems ranged from hydrophobic (toluene) to
hydrophilic (water) and the performance of the fly ashes were compared to that of C18 (octadecyl) and activated carbon. In water, the fly ashes demonstrated little preferential behavior with all PAHs and PCBs being removed from solution. Conversely, in systems with organic solvents, the fly ash accumulated PAHs and PCBs as a function of the solvent polarity and contaminant planarity. Finally, in an organic solvent system (i.e., hexane/acetone), the fly ashes demonstrated greater sorption capacity than C18 but less than activated carbon. These studies show that fly ash demonstrates a unique capability to sequester organic contaminants from organic and aqueous solutions.