Studies on the reaction pathway of arsenate adsorption at water-TiO2 interfaces using density functional theory

CORC > 生态环境研究中心 > 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

	Studies on the reaction pathway of arsenate adsorption at water-TiO2 interfaces using density functional theory
	He, Guangzhi ; Pan, Gang ; Zhang, Meiyi
刊名	JOURNAL OF COLLOID AND INTERFACE SCIENCE
	2011-12-15
卷号	364 期号:2 页码:476—481
中文摘要	Reaction pathway information of transition states and intermediate species is crucial for understanding the adsorption mechanism of pollutants at mineral-water interfaces. However, it has been difficult to obtain such information using existing experiments. Here, the activation barriers, transition states, intermediate species and surface complexes of arsenate adsorption on TiO2 surfaces were studied using DFT-based reaction pathway calculations. The results indicated that the bidentate binuclear (BB) adsorption structure was formed through a monodentate mononuclear (MM) metastable-equilibrium adsorption (MEA) state. A two-step adsorption mechanism was proposed on the basis of the detailed picture of bond breaking and bond formation during each reaction step. When the adjacent surface sites were occupied, the transform from MM mode to BB mode was greatly inhibited so that both MM and BB coexisted in the equilibrium adsorption sample. The BB complex was energetically more stable than the MM complex, and so, the adsorption irreversibility was fundamentally related to the ratio BB:MM in the final equilibrium state. This mechanism may also explain the initial concentration effect, where, for the given adsorption experiment of arsenate on TiO2 under the same thermodynamic conditions, both equilibrium constants and the BB:MM ratio in equilibrium adsorption samples changed with the reaction kinetics. (C) 2011 Elsevier Inc. All rights reserved.
WOS记录号	WOS:000296223500027
公开日期	2012-10-15
内容类型	期刊论文
源URL	[http://ir.rcees.ac.cn/handle/311016/6960]
专题	生态环境研究中心_环境水质学国家重点实验室
推荐引用方式 GB/T 7714	He, Guangzhi,Pan, Gang,Zhang, Meiyi. Studies on the reaction pathway of arsenate adsorption at water-TiO2 interfaces using density functional theory[J]. JOURNAL OF COLLOID AND INTERFACE SCIENCE,2011,364(2):476—481.
APA	He, Guangzhi,Pan, Gang,&Zhang, Meiyi.(2011).Studies on the reaction pathway of arsenate adsorption at water-TiO2 interfaces using density functional theory.JOURNAL OF COLLOID AND INTERFACE SCIENCE,364(2),476—481.
MLA	He, Guangzhi,et al."Studies on the reaction pathway of arsenate adsorption at water-TiO2 interfaces using density functional theory".JOURNAL OF COLLOID AND INTERFACE SCIENCE 364.2(2011):476—481.