Can Fe³⁺ and Al³⁺ ions serve as cationic bridges to facilitate the adsorption of anionic As(V) species on humic acids? A density functional theory study

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• 作者：Leonid Gorb ; Manoj K. Shukla
• 关键词：Anionic metals ; Humic acid ; DFT ; PCM ; Cationic bridge
• 刊名：Journal of Molecular Modeling
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：23
• 期：3
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Computer Applications in Chemistry; Molecular Medicine; Computer Appl. in Life Sciences; Characterization and Evaluation of Materials; Theoretical and Computational Chemistry;
• 出版者：Springer Berlin Heidelberg
• ISSN：0948-5023
• 卷排序：23

文摘

A computational chemistry investigation was undertaken to shed light on the facilitatory role played by Fe3+ and Al3+ cations in the adsorption of anionic As(V) species by humic acids through the formation of so-called cationic bridges. Geometric and energetic parameters were obtained using density functional theory at the B3LYP/6-31G(d,p) level in conjunction with the polarizable continuum model (to account for the influence of bulk water). We found that, despite their similar molecular geometries, the adsorption energies of the As(V) species AsO₄3− and H₂AsO4− differ when Fe3+, FeOH2+, Al3+, and AlOH2+ participate in the bridge. We also found that effective adsorption of As(V) species by humic acids strongly depends on whether the considered cationic bridges are tightly coordinated by humic acids at the adsorption sites, as well as on the rigidity of these humic acid adsorption sites.