Uranium removal from ground water using zero valent iron media
Uranium removal from ground water using zero valent iron media
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DOI：
10.1111/j.1745-6584.1999.tb01150.x
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发表时间：
1999-07-01
期刊：
影响因子：
2.6
通讯作者：
Fiedor, JN
中科院分区：
文献类型：
--
作者：
Farrell, J;Bostick, WD;Fiedor, JN
美国能源部 (DOE) 的多个设施目前正在评估使用零价铁从受污染地下水中去除铀的方法。零价铁去除铀可能是通过吸附在铁腐蚀产物上，以及通过与元素铁反应还原至不易溶解的价态来实现的。本研究调查了水化学和表面沉淀物堆积对零价铁去除可溶性铀的影响。进行批量测试以评估溶液化学对潜在铁腐蚀产物、磁铁矿和混合价无定形氧化铁的铀吸附的影响。铀对模拟铁腐蚀产物的吸附高度依赖于 pH 值以及背景电解质溶液的浓度和形态。尽管铁表面上堆积了多达 40,000 个单层沉淀铀，但通过元素铁还原去除铀非常接近伪一级去除动力学，这表明铀去除率并不强烈依赖于吸附铀层的厚度。所有测试溶液的短期铀还原率相似，但长期还原率高度依赖于水的化学性质。与去离子水相比，含氯化钠的溶液中的铀去除率增加，而硝酸钠溶液中的铀去除率降低。水化学对长期减排率的强烈影响表明系统设计将需要对感兴趣的地下水进行广泛的测试。
Removal of uranium from contaminated ground water using zero valent iron is currently under evaluation at several U.S. Department of Energy (DOE) facilities. Uranium removal by zero valent iron may occur via adsorption onto iron corrosion products, and by reduction to less soluble valence states by reactions with elemental iron, This research investigated the effects of water chemistry and surface precipitate buildup on the removal of soluble uranium by zero valent iron. Batch testing was performed to assess solution chemistry effects on uranium adsorption to the potential iron corrosion products, magnetite and a mixed valent amorphous iron oxide. Uranium adsorption to the simulated iron corrosion products was highly dependent on pH, and the concentration and speciation of the background electrolyte solution. Uranium removal via reduction by elemental iron closely approximated pseudo-first-order removal kinetics, despite the buildup of up to 40,000 monolayers of precipitated uranium on the iron surfaces, This indicates that the rate of uranium removal is not strongly dependent on the thickness of the adsorbed uranium layer. Short-term rates of uranium reduction were similar for all solutions tested, but long-term rates were highly dependent on water chemistry, Compared to deionized water uranium removal rates were increased in sodium chloride containing solutions and reduced in sodium nitrate solutions. The strong influence of water chemistry on long-term reduction rates indicates that system design will require extended testing with the ground water of interest.