Luo Lei, Zhang Shuzhen, Ma Yibing, Christie Peter, Huang Honglin
Research Center for Eco-Environmental Sciences, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China.
Environ Sci Technol. 2008 Apr 1;42(7):2414-9. doi: 10.1021/es702843m.
Effects of metal cations (Na+, Ca2+, and Al3+) on phenanthrene sorption were investigated using two soils with contrasting organic carbon (OC) contents. The presence of the polyvalent cations (i.e., Ca2+ or Al3+) at a concentration of 0.01 mol/L significantly increased the capacity and nonlinearity of phenanthrene sorption to soils compared with the monovalent Na+. The effects were governed by the content of soil OC. Rubbery OC (i.e., soft, amorphous OC including dissolved organic carbon (DOC)) tended to become condensed on soil surfaces as evidenced by a decrease in the signals of the 1H NMR spectra of DOC and an increase in the glass transition temperature (Tg) of the soils when the polyvalent cations were present. Increasing Ca2+ concentration led initially to an effect similar to that of the polyvalent cations in the low cation concentration range, and the effect was gradually attenuated as Ca2+ concentration further increased. These findings lead us to propose that the modifications in the physical configuration and chemical characteristics of OC resulting from the presence of metal cations account for the increase in the capacity and nonlinearity of phenanthrene sorption to the soils. This study points to an important role of metal cations in the sorption and fate of phenanthrene in the soil environment.
使用两种有机碳（OC）含量不同的土壤，研究了金属阳离子（Na+、Ca2+和Al3+）对菲吸附的影响。与单价Na+相比，浓度为0.01 mol/L的多价阳离子（即Ca2+或Al3+）的存在显著提高了菲在土壤上的吸附容量和非线性。这些影响受土壤有机碳含量的控制。橡胶态有机碳（即包括溶解有机碳（DOC）在内的软质、无定形有机碳）倾向于在土壤表面凝聚，这可由DOC的1H NMR光谱信号降低以及存在多价阳离子时土壤玻璃化转变温度（Tg）升高来证明。在低阳离子浓度范围内，Ca2+浓度增加最初会产生与多价阳离子类似的效果，随着Ca2+浓度进一步增加，这种效果会逐渐减弱。这些发现使我们提出，金属阳离子的存在导致有机碳物理构型和化学特性的改变，这解释了菲在土壤上吸附容量和非线性的增加。本研究指出了金属阳离子在土壤环境中菲的吸附和归宿方面的重要作用。
