Uranium is an important contaminant resulting from nuclear fuel processing, radiological waste storage and mining operations. In a study of the effects of long-term (six years) association of contaminant uranium with iron oxyhydroxides (often used in permeable reactive barriers (PRBs) to filter toxic metals like uranium out of groundwater), we found that the presence of uranium accelerates the aging process of the iron compounds. This may lead to degradation of the performance of the filtration/barrier systems, making long-term stewardship of contaminated sites or mines more difficult. In addition, zero-valent iron has received a significant amount of attention recently for its role in remediating contaminant metals from the environment. It has been proven effective in removing uranium from contaminated groundwater. The mechanism of this removal has not been fully elucidated, but it is likely to be electrochemical in nature. However, it is also likely that exposure to certain uranyl solutions of an acidic nature can accelerate the iron corrosion rate and the uranium may then become either trapped in occluded corrosion product layers or become chemically absorbed by hydroxide rich amorphous iron corrosion products.
展开▼
