Wu Wangsuo, Fan Qiaohui, Xu Junzheng, Niu Zhiwei, Lu Songsheng
Radiochemistry Laboratory, Lanzhou University, Lanzhou, 730000 Gansu, PR China.
Appl Radiat Isot. 2007 Oct;65(10):1108-14. doi: 10.1016/j.apradiso.2007.05.009. Epub 2007 Jun 3.
The sorption of Th(IV) on attapulgite was studied as a function of pH, ionic strength, temperature, attapulgite contents and Th(IV) concentrations under ambient conditions using a batch technique. The results indicated that sorption of Th(IV) on attapulgite was strongly affected by pH values, and weakly dependent on ionic strength. Sorption of Th(IV) was dominated by surface complexation, although ion exchange also contributed to this sorption. Sorption of Th(IV) increased with increasing temperature of the system. Enthalpy (DeltaH(0)), entropy (DeltaS(0)) and Gibbs free energy (DeltaG(0)) were calculated from the temperature-dependent sorption data; the results indicated that the sorption of Th(IV) on attapulgite was a spontaneous process. Sorption-desorption hysteresis indicated that the sorption of Th(IV) was irreversible, and that the Th(VI) adsorbed on attapulgite was difficult to be desorbed from solid to liquid phases.
在环境条件下，采用批次技术研究了针铁矿对Th(IV)的吸附作用，考察了pH值、离子强度、温度、针铁矿含量和Th(IV)浓度等因素的影响。结果表明，针铁矿对Th(IV)的吸附受pH值影响较大，受离子强度影响较小。Th(IV)的吸附以表面络合为主，离子交换也对吸附有一定贡献。Th(IV)的吸附量随体系温度升高而增加。根据温度依赖型吸附数据计算了焓变(ΔH(0))、熵变(ΔS(0))和吉布斯自由能变(ΔG(0))；结果表明，Th(IV)在针铁矿上的吸附是一个自发过程。吸附-解吸滞后表明Th(IV)的吸附是不可逆的，吸附在针铁矿上的Th(VI)难以从固相向液相解吸。
