Laboratory for Waste Management, Paul Scherrer Institut , 5232 Villigen PSI, Switzerland.
Environ Sci Technol. 2014;48(15):8698-705. doi: 10.1021/es501902f. Epub 2014 Jul 8.
Fe(II) sorption edges and isotherms have been measured on low structural Fe-content montmorillonite (STx) and high structural Fe-content montmorillonite (SWy) under anoxic (O2 < 0.1 ppm) and strongly reducing conditions (Eh = -0.64 V). Under anoxic conditions Fe(II) sorption on SWy was significantly higher than on STx, whereas the sorption under reducing conditions was essentially the same. The uptake behavior of Fe(II) on STx under all redox conditions (Eh = +0.28 to -0.64 V) and SWy under reducing conditions (Eh = -0.64 V) was consistent with previous measurements made on other divalent transition metals. All of the sorption data could be modeled with the two-site protolysis nonelectrostatic surface complexation and cation exchange (2SPNE SC/CE) sorption model including an additional surface complexation reaction for Fe(II) which involved the surface oxidation of ferrous iron surface complexes (≡S(S,W)OFe(+)) to ferric iron surface complexes (≡S(S,W)OFe(2+)) on both the strong and weak sites. The electron acceptor sites on the montmorillonite are postulated to be the structural Fe(III).
在缺氧（O2 < 0.1 ppm）和强还原条件（Eh = -0.64 V）下，测量了低结构铁含量蒙脱石（STx）和高结构铁含量蒙脱石（SWy）上的 Fe(II) 吸附边缘和等温线。在缺氧条件下，SWy 上的 Fe(II) 吸附量明显高于 STx，而在还原条件下的吸附量基本相同。在所有氧化还原条件（Eh = +0.28 至 -0.64 V）下，STx 上 Fe(II) 的摄取行为以及在还原条件（Eh = -0.64 V）下的 SWy 与其他二价过渡金属的先前测量结果一致。所有吸附数据都可以用两个位点质子化非静电表面络合和阳离子交换（2SPNE SC/CE）吸附模型进行建模，该模型包括一个额外的表面络合反应，涉及亚铁表面络合物（≡S(S,W)OFe(+))在强和弱位点上表面氧化为铁表面络合物（≡S(S,W)OFe(2+))。蒙脱石上的电子受体位点被假定为结构 Fe(III)。
