Riebe B, Bors J, Dultz S
Center of Radiation Protection and Radioecology, Hannover University, Herrenhäuser Str. 2, D-30419 Hannover, Germany.
J Contam Hydrol. 2001 Feb;47(2-4):255-64. doi: 10.1016/s0169-7722(00)00154-6.
Sorption and diffusivity of iodide and pertechnetate (I- and TcO4-) on MX-80 bentonite with different hexadecylpyridinium (HDPy+) loadings were studied using equilibrium solutions of different ionic strengths. In HDPy(+)-modified bentonite, iodide and pertechnetate ions exhibited increasing sorption (characterized by the distribution ratio, Rd), while Cs+ and Sr2+ showed decreasing sorption with increasing organophilicity. In case of medium-loading levels, the simultaneous sorption of anions (I- and TcO4-) and cations (Cs+ and Sr2+) was observed. Sorption of ions was influenced by the composition of the electrolytes employed. It decreased gradually with increasing ionic strength of the electrolyte solutions. The experiments revealed the general tendency that the diffusivity (Da [cm2.s-1]) for iodide and pertechnetate decreases with increasing organophilicity and increases with increasing ionic strength of the equilibrium solutions, confirming the results of the sorption experiments. Additionally, some mineralogical and chemical investigations, like IR spectral analysis of the organo-bentonite samples and exchange behavior of HDPy+, were performed. On the basis of these analyses, it was concluded that the alkylammonium ions are sorbed as (1) HDPy+ cations, (2) HDPyCl molecules and (3) micelles with decreasing binding intensities in this order.
利用不同离子强度的平衡溶液，研究了不同十六烷基吡啶鎓（HDPy⁺）负载量的MX - 80膨润土对碘化物和高锝酸盐（I⁻和TcO₄⁻）的吸附及扩散率。在HDPy⁺改性膨润土中，碘化物和高锝酸根离子的吸附量增加（以分配比Rd表征），而Cs⁺和Sr²⁺的吸附量随亲有机性增加而降低。在中等负载水平下，观察到阴离子（I⁻和TcO₄⁻）和阳离子（Cs⁺和Sr²⁺）的同时吸附。离子的吸附受所用电解质组成的影响。随着电解质溶液离子强度的增加，吸附量逐渐降低。实验揭示了一般趋势，即碘化物和高锝酸盐的扩散率（Da [cm²·s⁻¹]）随亲有机性增加而降低，随平衡溶液离子强度增加而增加，这证实了吸附实验的结果。此外，还进行了一些矿物学和化学研究，如有机膨润土样品的红外光谱分析和HDPy⁺的交换行为。基于这些分析，得出结论：烷基铵离子按（1）HDPy⁺阳离子、（2）HDPyCl分子和（3）胶束的顺序以递减的结合强度被吸附。
