铝氧化物除砷的密度泛函理论研究

Density Functional Theory Study on Removal of Arsenic from Aluminum Oxide

摘要: 本文采用密度泛函理论的B3LYP方法研究了氧化铝和羟基氧化铝的单体和二聚体与不同质子化砷酸根物种的缔合情况。研究表明，氧化铝与不同质子化砷酸缔合方式倾向于单齿双核；羟基氧化铝与AsO₄^3-和HAsO₄^2-倾向以单齿双核缔合，而与H₂AsO₄^-倾向以单齿单核缔合。羟基氧化铝中的羟基O与质子化砷酸的H易形成氢键。氧化铝和羟基氧化铝与H_mAsO₄^3-m(m = 0~2)缔合强于氧化铁和羟基氧化铁。羟基氧化铝二聚体与倾向以双核双齿缔合方式与AsO₄^3-和HAsO₄^2-缔合，而和H₂AsO₄^-的双核双齿和单核单齿结构的缔合能几乎相等。羟基氧化铝二聚体与不同质子化砷酸根物种的缔合结构都显示双齿双核的缔合构型比单齿单核构型稳定。

Abstract: In this paper, the B3LYP method of density functional theory method was used to study the association of monomer and dimer of alumina and hydroxyl alumina with different arsenate species. Studies have shown that the association structures between alumina and different arsenate species and arsenate species tend to be mononuclear bidentate, hydroxyl alumina tends to associate with AsO₄^3- and HAsO₄^2- in mononuclear bidentate mode, while H₂AsO₄^- as the mononuclear mono-dentate mode. Hydroxyl O in hydroxyl alumina and H of protonated ararsenic acid are easy to form hydrogen bonds. The association of alumina and hydroxyl alumina with H_mAsO₄^3-m (m = 0~2) is stronger than that of iron oxide and hydroxyl oxide. The hydroxyl alumina dimer tends to associate with AsO₄^3- and HAsO₄^2- in a dinuclear bidentate mode, while the association energy of dinuclear bidentate association and mononuclear monodentate association with H₂AsO₄^- is almost equal. The associative structures of hydroxylated alumina dimer and different protonated arsenate spe-cies show that the dinuclear bidentate structures are more stable than mononuclear monodentate structures.