Sorption of selenite ions on hematite
Sorption of selenite ions on hematite
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DOI：
10.1016/j.jcis.2006.01.029
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发表时间：
2006-06-15
影响因子：
9.9
通讯作者：
Fedoroff, M.
中科院分区：
文献类型：
--
作者：
Duc, M.;Lefevre, G.;Fedoroff, M.
研究了pH（2-12）、离子强度（0.01- 0.1M）和硒浓度（10（-7）-10（-2）M）对赤铁矿吸附亚硒酸根的影响。吸附可以根据两个过程进行：表面络合，然后沉淀亚硒酸铁开始在约[Se] = 4 × 10（-4）M（表面覆盖度>约。2在nm（-2）处）。吸附等温线用Tempkin方程拟合。表面络合模型（2-pK/恒定电容模型）被用来拟合吸附数据。由于单齿> FeO-Se（O）O-或> FeO-Se（O）OH和双齿（> FeO）（2）SeO表面络合物都能拟合实验数据，因此不能通过模型来确定SeO表面物种的性质。研究了吸附的可逆性和动力学。将亚硒酸盐离子对赤铁矿的亲和力（表示为相对于表面积的分配系数（K-D，Lm（-2）与其他氧化铁（针铁矿和无定形氧化铁）的结果进行了比较。结果发现，对亚硒酸盐的反应性是相似的，相反的酸碱性质取决于氧化物的性质和其纯度水平。(c)2006爱思唯尔公司All rights reserved.
The sorption of selenite from aqueous solutions onto hematite was investigated as a function of pH (2-12), ionic strength (0.01-0.1 M), and concentration of selenium (10(-7)-10(-2) M). The sorption may proceed according to two processes: surface complexation, followed by the precipitation of ferric selenite starting at approximate [Se] = 4 x 10(-4) M (surface coverage > ca. 2 at nm(-2)). The sorption isotherms have been fitted by a Tempkin equation. A surface complexation model (2-pK/Constant Capacitance Model) was used to fit the sorption data. The nature of the surface species of selenite cannot be determined by modeling since monodentate > FeO-Se(O)O- or > FeO-Se(O)OH and bidentate (> FeO)(2)SeO Surface complexes are both able to fit the experimental data. The reversibility and kinetics of sorption were also studied. The affinity of selenite ions toward hematite, expressed as the distribution coefficient with respect to the surface area (K-D in Lm(-2)), was compared with results published for other ferric oxides (goethite and amorphous ferric oxide). It was found that the reactivity toward selenite is similar, contrary to acid-base properties which depend on the nature of the oxide and its level of purity. (c) 2006 Elsevier Inc. All rights reserved.