Investigations using sorbent media including methylsilicone gums (for UV spectroscopy) and `Parafilm` (for FT-IR) have shown that quantitative determinations of aromatic fuel components, such as benzene and alkylbenzenes (BTEX), can be achieved using UV spectrometry, and of common solvents (e.g., chloroform and other chlorinated solvents) can be achieved using FT-IR. This new approach is based on the preconcentration of organic pollutants in optically clear sorbent media followed by measurement with either ultraviolet (UV) spectroscopy or Fourier transform infrared spectrometry (FT-IR). Specific objectives include: understanding the mechanism for capture of Hg Environmental Research Center (EERC) that has been demonstrated to yield good sensitivities (ppb to ppm) and be easily adapted for rapid (less more » than 30 minutes) and inexpensive field surveys. The overall project goal is to develop an understanding of sorbent chemistry and capitalize on that development to produce more effective mercury sorbents targeted at specific applications for both coal combustion and incinerators. These issues will be addressed in a second or third year of research. However, much of the work may be generalized to other mercury cleanup needs such as spill cleanup, soil contamination, and water treatment. The proposed work for this year addresses mercury control only for gas stream applications such as combustion processes. Results to date on these activities are described. The project objectives are to relate mercury capture by fly ash to chemical and physical properties of the fly ash, determine mercury associations with submicron aerosols, evaluate mercury capture on metal sorbents, and relate experimental results to predictions based on state-of-the-art models.
more » Another possible explanation of mercury capture on fly ash is the formation of amalgams with other metal species that may be present in the fly ash if this is true, amalgamation may be a viable control technology. Since much of the fly ash surface area is concentrated on submicron particles, the interaction of mercury with submicron particles needs to be evaluated. The chemical nature of the exposed surfaces and the amount of surface area are likely to affect the amount of mercury capture, so both of these parameters must be explored. Several capture mechanisms and interactions may be possible, such as condensation, chemical adsorption, physical adsorption, chemical bonding, and amalgamation. Determining the fly ash properties responsible for the capture of mercury in coal-fired power generation systems is key to understanding and controlling mercury emissions in these systems.
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