Pepper Sarah E, Bunker Debbie J, Bryan Nicholas D, Livens Francis R, Charnock John M, Pattrick Richard A D, Collison David
Centre for Radiochemistry Research, Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
J Colloid Interface Sci. 2003 Dec 15;268(2):408-12. doi: 10.1016/j.jcis.2003.08.024.
Technetium is a long-lived product of nuclear fission that readily forms the soluble pertechnetate anion TcO(4). Green rusts (layered hydrous oxides containing both Fe(II) and Fe(III) and with interlayer sulfate or carbonate anions) concentrate >99.8% of 99Tc, present as TcO(4), from aqueous solution, even in the presence of high concentrations of NaNO(3), a common constituent of radioactive waste streams. The mechanism of removal from solution is apparently reduction and formation of strong Tc(IV) surface complexes. X-ray absorption spectroscopy shows that TcO(4) is indeed reduced by reaction with both sulfate- and carbonate-form green rusts and is found in a TcO(2)-like environment. On contact with air, the green rusts oxidize to poorly crystalline goethite but the Tc environment is unchanged. There is no increase in Tc solubility associated with oxidation of the host green rust. This behavior suggests that green rusts may be useful in the treatment of Tc-containing waste streams, in groundwater cleanup, and in restricting Tc migration from repositories.
锝是核裂变的一种长寿命产物，它很容易形成可溶性的高锝酸根阴离子[TcO(4)]-。绿锈（含有Fe(II)和Fe(III)且层间有硫酸根或碳酸根阴离子的层状含水氧化物）能从水溶液中富集>99.8%的99Tc，其以[TcO(4)]-形式存在，即使在放射性废物流的常见成分高浓度NaNO(3)存在的情况下也是如此。从溶液中去除锝的机制显然是还原以及形成强的Tc(IV)表面络合物。X射线吸收光谱表明，[TcO(4)]-确实会与硫酸根型和碳酸根型绿锈反应而被还原，并存在于类似TcO(2)的环境中。与空气接触时，绿锈会氧化成结晶性较差的针铁矿，但锝的环境不变。主体绿锈的氧化不会导致锝的溶解度增加。这种行为表明，绿锈在含锝废物流的处理、地下水净化以及限制锝从储存库迁移方面可能会很有用。
