Sutton M, Warwick P, Hall A
Department of Chemistry, Loughborough University, UK.
J Environ Monit. 2003 Dec;5(6):922-8. doi: 10.1039/b308554f.
The sorption of uranium on to Ordinary Portland Cement (OPC)/Pulverized Fuel Ash (PFA, fly ash) grout material has been investigated with respect to time, pH, grout:uranium ratio and the chemical composition of the supporting solution. The information obtained is of relevance to the disposal of low-level nuclear waste. The grout material has been chemically characterised and is negatively charged above pH 2.3. At the uranium concentrations studied (2 microM) all uranyl hydroxide aqueous species are expected to be monomeric, rather than polymeric. Uranium(VI) sorption on to the grout material has been explained in terms of inner sphere complexation binding by means of hydroxide bridge formation between the uranium and grout surface. It is also proposed that oligomeric uranyl species are formed across the grout surface, perhaps stabilising the repulsive effects of the negatively charged grout surface and anionic uranyl hydroxide species. Thermodynamic modelling has been used to explain the sorption variation versus solution pH and identifies potential binding mechanisms.
针对时间、pH值、灌浆料与铀的比例以及支撑溶液的化学成分，研究了铀在普通硅酸盐水泥（OPC）/粉煤灰（PFA）灌浆材料上的吸附情况。所获得的信息与低水平核废料的处置相关。对灌浆材料进行了化学表征，其在pH值高于2.3时带负电荷。在所研究的铀浓度（2 microM）下，预计所有氢氧化铀酰水合物种均为单体，而非聚合物。已根据通过铀与灌浆材料表面之间形成氢氧化物桥的内球络合结合来解释铀（VI）在灌浆材料上的吸附。还提出在灌浆材料表面形成低聚铀酰物种，这可能稳定了带负电荷的灌浆材料表面和阴离子氢氧化铀酰物种的排斥作用。已使用热力学模型来解释吸附随溶液pH值的变化，并确定潜在的结合机制。
