| EXAFS研究Zn在δ-MnO2上的吸附-解吸机理 |
| |
| 引用本文： | 潘纲,李贤良,秦延文,胡天斗,吴自玉,谢亚宁.EXAFS研究Zn在δ-MnO2上的吸附-解吸机理[J].环境科学,2003,24(4):54-59. |
| |
| 作者姓名： | 潘纲 李贤良 秦延文 胡天斗 吴自玉 谢亚宁 |
| |
| 作者单位： | 中国科学院生态环境研究中心环境水质学国家重点实验室,北京,100085;中国科学院生态环境研究中心环境水质学国家重点实验室,北京,100085;中国科学院生态环境研究中心环境水质学国家重点实验室,北京,100085;中国科学院高能物理研究所同步辐射室,北京,100039;中国科学院高能物理研究所同步辐射室,北京,100039;中国科学院高能物理研究所同步辐射室,北京,100039 |
| |
| 基金项目： | 国家自然科学基金资助项目(20073060);中科院百人计划项目 |
| |
| 摘 要： | 用延展X-ray吸收精细结构光谱(EXAFS)研究了重金属Zn(Ⅱ)在δ-MnO2上吸附产物的微观结构及其吸附机制.在pH 5.50,0.1mol/L NaNO3介质中,吸附在δ-MnO2表面上Zn(Ⅱ)以六配位的水合离子八面体形式存在.水合锌离子八面体从δ-MnO2层状结构的空位上下方,与δ-MnO2的结构单元MnO6八面体通过共用O原子结合,形成角-角结合的弱吸附,Zn-O平均原子间距为(2.071±0.007)A(n=3),Zn-Mn平均原子间距为(3.528±0.006)A(n=3).在同一条等温线上随着吸附量增加,以角-角结合的弱吸附形式基本上没有变化.宏观的吸附-解吸实验结果显示Zn(Ⅱ)在δ-MnO2上的吸附可逆性很高,解吸等温线和吸附等温线几乎重合在一起EXAFS结果从分子水平表明,Zn(Ⅱ)在δ-MnO2上的高吸附可逆性是由角-角形式弱吸附所导致的.
|
| 关 键 词： | EXAFS Zn δMnO2 吸附机制 吸附可逆性 |
| 文章编号： | 0250-3301(2003)04-06-0054 |
| 收稿时间： | 2002/11/27 0:00:00 |
| 修稿时间： | 2002年11月27 |
EXAFS studies on adsorption-desorption mechanism of Zn at delta-MnO2-water interface |
| |
| Pan Gang,Li Xianliang,Qin Yanwen,Qin Yanwen,Wu Ziyu and Xie Yaning.EXAFS studies on adsorption-desorption mechanism of Zn at delta-MnO2-water interface[J].Chinese Journal of Environmental Science,2003,24(4):54-59. |
| |
| Authors: | Pan Gang Li Xianliang Qin Yanwen Qin Yanwen Wu Ziyu and Xie Yaning |
| |
| Institution: | State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. |
| |
| Abstract: | Microscopic structures of Zn(II) surface complexes adsorbed at a delta-MnO2-water interface were studied using extended X-ray absorption fine structure (EXAFS) spectroscopy. In a 0.1 mol/L NaNO3 solution of pH 5.50, Zn(II) was adsorbed onto the solid surface in the form of octahedral hydrous Zn(II) ions. The octahedral Zn(II) was linked to the structural unit of octahedral MnO6 of the delta-MnO2 surface by sharing the O atoms. The average bond length of RZn-O was (2.071 +/- 0.007)A (n = 3) and the Zn-Mn atomic distance was (3.528 +/- 0.006) A (n = 3), which corresponded to a corner-sharing linkage adsorption mode (weaker adsorption). Macroscopic adsorption-desorption isotherm experiments showed that, in contrast to that of Zn-manganite, adsorption of Zn(II) on delta-MnO2 was highly reversible and no apparent adsorption hysteresis was observed. EXAFS results indicated that the microscopic mechanism for the high adsorption reversibility was corresponded to the weak adsorption sites of corner sharing linkage between the adsorbate and adsorbent polyhedra. |
| |
| Keywords: | |
| 本文献已被 CNKI PubMed 等数据库收录！ |
| 点击此处可从《环境科学》浏览原始摘要信息 |
| 点击此处可从《环境科学》下载免费的PDF全文 |
|
