Structural model of arsenic(III) adsorbed on gibbsite based on DFT calculations

被引:33
作者
Oliveira, Augusto F.
Ladeira, Ana Claudia Q.
Ciminelli, Virginia S. T.
Heine, Thomas
Duarte, Helio A. [1 ]
机构
[1] Univ Fed Minas Gerais, Dept Quim, BR-31270901 Belo Horizonte, MG, Brazil
[2] Univ Fed Minas Gerais, Dept Met & Mat Engn, BR-31270901 Belo Horizonte, MG, Brazil
[3] CDTN, Ctr Desenvolvimento Tecnol Nucl, BR-31270010 Belo Horizonte, MG, Brazil
[4] TU Dresden, Inst Phys Chem & Elektrochem, D-01062 Dresden, Germany
来源
JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM | 2006年 / 762卷 / 1-3期
关键词
gibbsite; arsenic; As(III); H3AsO3; adsorption; DFT; cluster model;
D O I
10.1016/j.theochem.2005.08.038
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
It is well known that As(III) has a higher mobility compared to As(V) in the environment. This fact is explained by the high reversibility of As(III) adsorption on minerals such as Al (hydr)oxides. Nevertheless, experimental results pointed out that adsorption of As(III) leads to innersphere complexes, which appears to be in conflict with the high mobility of these species as inner-sphere complexes should be strongly attached. In this work we used density functional methods and cluster models to study two different mechanisms for the H3AsO3 adsorption on gibbsite-gamma-Al(OH)(3), one of the most abundant aluminum hydroxide minerals. Our results show that, differently from the As(V) case, As(III) is not adsorbed via an acid/base. but by a non-dissociative mechanism in which O-H bonds are not being broken. This non-dissociative mechanism also conciliates the hi-h remobilization of As(III) with the apparently inconsistent formation of inner-sphere adsorption complexes. (c) 2005 Elsevier B.V. All rights reserved.
引用
收藏
页码:17 / 23
页数:7
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