利用电位滴定表征了铁铈氧化物(Fe-Ce)的表面电荷特性,并使用电荷分布多位络合模型(CDMUSIC)进行了模拟,得到Fe-Ce材料的表面位质子结合常数为5.8,位密度为23.2个·nm^-2。,高于大多数铁氧化物的表面位密度.在Fe-Ce表面特性参数的基础上。进一步使用CD MUSIC模型对系列PH(5—9)下As(V)在Fe-Ce表面的等温吸附实验进行了模拟.结果表明,单齿单核单质子化形态zFeOAsO3H^1.5-和双齿双核非质子化形态=Fe2O2AsO2^2-共存于吸附后的Fe-Ce表面。它们的结合常数分别为31.5和34.2,电荷分布值(力分别为0.25和0.50.使用以上模型参数,对pH3.5-10.5范围内2种表面络合形态分布趋势进行了预测.结果表明,在偏酸性条件下。=FeOAsO3H^1.5-形态占主导;而=Fe2O2AsO2^2-形态主要存在于偏碱性的范围.
The adsorption mechanism of arsenic on an Fe-Ce oxide was studied by using the charge-distribution muhisite complexation ( CD MUSIC) model. The fitting results showed that the surface protonation constant is 5.8, and the site density is 23.2 sites nm -2, which was higher than most of the iron oxides. And the isotherms of As(V) adsorption on the Fe-Ce oxide at pH 5 - 9 was then modeled using the CD MUSIC model. The fitting results showed that =FeOAsO3 H^1.5- and =Fe2 O2 AsO2^2- coexisted on the surface of the Fe-Ce oxide, and their surface complexation constants are 31.5 and 34.2, and the CD factors are 0.25 and 0.5, respectively. The distribution and abundance of these two surface species at pH 3.5 - 10.5 was further predicted using the CD MUSIC model. It is shown that = FeOAsO3 H^1.5 - dominated under acidic conditions, while = Fe2 O2 AsO2^2- was abundant under alkaline conditions.