Perrhenate uptake by iron and aluminum oxyhydroxides: an analogue for pertechnetate incorporation in Hanford waste tank sludges.
Perrhenate uptake by iron and aluminum oxyhydroxides: an analogue for pertechnetate incorporation in Hanford waste tank sludges.
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DOI：
10.1021/es0348795
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发表时间：
2004-02
影响因子：
11.4
通讯作者：
Bradley Wakoff;K. L. Nagy
中科院分区：
文献类型：
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作者：
Bradley Wakoff;K. L. Nagy
高锰酸盐(ReO4-)是高锰酸盐(99TcO4-)的非放射性替代物，在沉淀和老化过程中，从储存在华盛顿州汉福德的高级核废料的模拟水溶液中分离出氢氧化铁和铝固体。酸性金属硝酸盐溶液(Al/Fe摩尔比0.25和13.5；40ppm Re)中和到最终pH&Gt；13，然后在90℃下老化长达18周，导致大量可逆吸附的Re(约1-10ppm)。在以铁为主的体系中，Re的不可逆吸附随着时间的推移而增加，在赤铁矿和少量针铁矿的混合物中，168h后最终达到约83 ppb。在以薄水铝石为主的固体中，以铝为主的体系中不可逆吸附的Re一般随着时间的推移而减少到18周后约30 ppb。将Re的总量增加到1000ppm会增加不可逆吸附的程度。在以铁为主的体系中，100ppm硅的存在阻止了高铁水合物的转变和不可逆的Re吸收。在铝为主的体系中，200ppm的镍阻止了赤铁矿的形成，但不影响高铁酸盐的吸收。结果表明，在汉福德废水池中，5%的99Tc库存可能与污泥有关，而在氧化条件下，约有0.5%的99Tc与固体相结合。
Perrhenate (ReO4-), a nonradioactive surrogate for pertechnetate (99TcO4-), was partitioned during precipitation and aging of iron and aluminum oxyhydroxide solids from aqueous simulants of high-level nuclear waste stored at Hanford, WA. Neutralization of acidic metal nitrate solutions (Al/Fe mole ratio 0.25 and 13.5; 40 ppm Re) to a final pH > 13, followed by aging at 90 degrees C for up to 18 weeks, resulted in substantial amounts of reversibly sorbed Re (approximately 1-10 ppm). Irreversibly sorbed Re increased in the Fe-dominated system with aging, reaching a final value of approximately 83 ppb after 168 h, in a mixture of hematite with minor goethite. Irreversibly sorbed Re in the Al-dominated system generally decreased with time to approximately 30 ppb after 18 weeks in solids dominated by boehmite. Increasing the total amount of Re to 1000 ppm increased the extent of irreversible sorption. The presence of 100 ppm Si prevented transformation of and irreversible Re uptake by ferrihydrite in Fe-dominated systems. In Al-dominated systems, 200 ppm Ni prevented hematite formation but did not affect perrhenate uptake. Results suggest that 5% of the 99Tc inventory in the Hanford waste tanks may be associated with the sludges, and approximately 0.5% incorporated into the solids under oxidizing conditions.