School of Materials and Chemical Engineering, Anhui University of Architecture, Hefei 230601, PR China.
J Environ Radioact. 2012 Jan;103(1):20-9. doi: 10.1016/j.jenvrad.2011.08.010. Epub 2011 Sep 25.
In this study, the sorption of U(VI) from aqueous solution on hematite was studied as a function of various water quality parameters such as contact time, pH, ionic strength, soil humic acid (HA) or fulvic acid (FA), solid content and temperature by using a batch technique. The results demonstrated that the sorption of U(VI) was strongly dependent on ionic strength at pH<6.0, and outer-sphere surface complexation may be the main sorption mechanism. The sorption was independent of ionic strength at pH>6.0 and the sorption was mainly dominated by inner-sphere surface complexation. The presence of HA/FA increases U(VI) sorption at low pH, whereas decreases U(VI) sorption at high pH. The thermodynamic parameters (ΔH⁰, ΔS⁰, and ΔG⁰) were calculated from the temperature dependent sorption isotherms, and the results suggested that U(VI) sorption was a spontaneous and endothermic process. The results might be important for the application of hematite in U(VI) pollution management.
在这项研究中，通过使用批量技术，研究了水相中赤铁矿对 U(VI)的吸附，作为各种水质参数（如接触时间、pH 值、离子强度、土壤腐殖酸 (HA) 或富里酸 (FA)、固体含量和温度）的函数。结果表明，在 pH<6.0 时，U(VI)的吸附强烈依赖于离子强度，并且可能是外球表面络合是主要的吸附机制。在 pH>6.0 时，吸附与离子强度无关，吸附主要由内球表面络合控制。HA/FA 的存在会增加低 pH 下 U(VI)的吸附，而在高 pH 下会降低 U(VI)的吸附。从温度依赖的吸附等温线上计算了热力学参数 (ΔH⁰、ΔS⁰ 和 ΔG⁰)，结果表明 U(VI)的吸附是一个自发和吸热的过程。这些结果对于赤铁矿在 U(VI)污染管理中的应用可能很重要。
