CAJ | 학술논문

采用密度泛函理论广义梯度近似平面波赝势法,结合周期平板模型,探讨了水体环境中Pb(OH)+在高岭石铝氧八面体(001)晶面的吸附行为和机理,确定了吸附配合物的结构、配位数、优势吸附位和吸附类型.结果表明, Pb(II)与高岭石铝氧(001)面的氧原子形成单齿或双齿配合物,其配位数为3-5,均为半方位构型.高岭石表面存在含“平伏”氢原子的表面氧(Ol)位和含“直立”氢原子的氧(Ou)位,后者更易与Pb(OH)+单齿配位,该吸附配合物具有较高的结合能(-182.60 kJ?mol-1),为优势吸附物种；高岭石表面位于同一个Al原子上的“OuOl”位可形成双齿配合物.表面Ol与水分子配体形成氢键,对配合物的稳定性起到关键作用. Mul iken布居和态密度分析表明,高岭石单齿配合物中Pb-O成键机理主要为Pb 6p轨道与Pb 6s-O 2p反键轨道进行耦合,电子转移到反键轨道.双齿配合物“Pb-Ol-H”共配位结构中,受配位氢原子影响, Pb-Ol成键过程成键态电子填充占主导地位.
채용밀도범함이론엄의제도근사평면파안세법,결합주기평판모형,탐토료수체배경중Pb(OH)+재고령석려양팔면체(001)정면적흡부행위화궤리,학정료흡부배합물적결구、배위수、우세흡부위화흡부류형.결과표명, Pb(II)여고령석려양(001)면적양원자형성단치혹쌍치배합물,기배위수위3-5,균위반방위구형.고령석표면존재함“평복”경원자적표면양(Ol)위화함“직립”경원자적양(Ou)위,후자경역여Pb(OH)+단치배위,해흡부배합물구유교고적결합능(-182.60 kJ?mol-1),위우세흡부물충；고령석표면위우동일개Al원자상적“OuOl”위가형성쌍치배합물.표면Ol여수분자배체형성경건,대배합물적은정성기도관건작용. Mul iken포거화태밀도분석표명,고령석단치배합물중Pb-O성건궤리주요위Pb 6p궤도여Pb 6s-O 2p반건궤도진행우합,전자전이도반건궤도.쌍치배합물“Pb-Ol-H”공배위결구중,수배위경원자영향, Pb-Ol성건과정성건태전자전충점주도지위.
The adsorption behavior of Pb(OH)+ on the basal octahedral (001) surface of kaolinite has been investigated using the Perdew-Burke-Ernzerhof generalized gradient approximation (GGA-PBE) of density functional theory with periodic slab models, where the water environment was considered. The coordination geometry, coordination number, preferred adsorption position, and adsorption type were examined, with binding energy estimated. Al the monodentate and bidentate complexes exhibited hemi- directed geometry with coordination numbers of 3-5. Site of“Ou”with“up”hydrogen was more favorable for monodentate complex than site of“Ol”with“lying”hydrogen. Monodentate complexation of“Ou”site with a high binding energy of -182.60 kJ?mol-1 should be the most preferred adsorption mode, while bidentate complexation on“OuOl”site of single Al center was also probable. The stability of adsorption complex was found closely related to the hydrogen bonding interactions between surface Ol and H in aqua ligands of Pb(II). Mul iken population and density of states analyses showed that coupling of Pb 6p with the antibonding Pb 6s-O 2p states was the primary orbital interaction between Pb(II) and the surface oxygen. Hydrogen complexation occupied a much large proportion in the joint coordination structure of bidentate complex, where bonding state fil ing predominated for the Pb-Ol interaction.