摘要
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.
出处
《环境科学学报》
CAS
CSCD
北大核心
2006年第10期1592-1599,共8页
Acta Scientiae Circumstantiae
基金
国家自然科学基金项目(No.20207013)
国家"863"青年基金项目(No.2004AA649280)~~
关键词
铁铈氧化物
砷
电位滴定
表面络合模型
Fe-Ce oxide
arsenic
potentiometric titration
surface complexation model
