The development of highly efficient liquid phase remediation technologies for chlorinated organics and the simultaneous understanding of health and nutrition effects are critical for solving Superfund site problems. Reductive dehalogenation technologies, in contrast to oxidative techniques, are known to provide complete detoxification. Reductive processes (zero-valent iron, vitamin B12) can lead to complete dehalogenation to HC1, water and non-halogenated volatile organics if the degradation pathways are controlled. Understanding and control of the degradation pathways to yield innocuous degradation products in short residence times (less than 1 hour) under ambient temperature conditions has yet to be accomplished. The overall objectives of this work are to study the role of the reductive agent morphology on the product distribution and rate, establish the degradation rates of intermediate byproducts (vinyl chloride is an example), and close the elemental balances (particularly C and C1) around the degradation processes. The reductive agent systems to be investigated are zero-valent iron particles, zero-valent nanoscale metal particles and composites, high surface area/high porosity iron coated composites, and novel immobilized vitamin B12 derivative (electropolymerization) systems. With Vitamin B12 the overall rates can be enhanced by incorporating the active complex in polymer films and by using electrochemical techniques to regenerate the active enter. The role of surface morphology and the development of highly reactive materials to reduce reaction time and to enhance intermediate product degradation rates needs thorough investigation for the development of highly efficient remediation systems. In addition to the development of highly versatile models for chlorinated organics dehalogenation rates, we plan to establish the reactive surface morphology (by ARM and XPS methods) changes as a function of reaction time.
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