The effect of pH on the adsorption of arsenic(III) and arsenic(V) at the TiO2 anatase [101] surface
The effect of pH on the adsorption of arsenic(III) and arsenic(V) at the TiO2 anatase [101] surface
复制标题
pH值对TiO2锐钛矿[101]表面吸附砷(III)和砷(V)的影响
DOI：
10.1016/j.jcis.2015.10.018
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发表时间：
2016
影响因子：
9.9
通讯作者：
Hu Guanghui
中科院分区：
文献类型：
--
作者：
Wei Zhigang;Liang Kai;Wu Yang;Zou Y;i;Zuo Junhui;Cortes Arriagada Diego;Pan Zhanchang;Hu Guanghui
Octahedral TiO2nanocrystals (OTNs) have been prepared by a hydrothermal method with the main surface of (1 0 1). Then the arsenic adsorption behavior on OTNs is investigated in a broad experimental pH range from 1.0 to 13.5. The maximum adsorptions of arsenite (As(III)) and arsenate (As(V)) appear at pH values 8 and 4, respectively. It is interesting to see that the minimum adsorptions of As(III) and As(V) are both at pH 12 and then their adsorptions increase again at higher pH values such as 13.0 and 13.5. To our best knowledge, it is quite new to report the arsenic adsorption on the controlled TiO2surface especially at very high pH values. These results might be helpful to understand the adsorption mechanism. On the other hand, periodic slab models of TiO2anatase (1 0 1) surface with some H+cations, some water molecules or some OH−ions are suggested to simulate the pH effect. Using these models, the adsorptions of As(III) and As(V) are simulated by the density functional theory (DFT) method. Qualitatively, the adsorption abilities of arsenic species, water and OH−follow the order of AsO33−> OH−> HAsO32−> H2AsO3−> H2O > H3AsO3for As(III) and AsO43−> OH−> HAsO42−> H2AsO4−> H3AsO4> H2O for As(V). It implies that H2AsO3−should be the major As(III) species at pH 8 and H2AsO4−should be the major As(V) species at pH 4, and the most negative charged ions AsO33−and AsO43−should correspond to the adsorptions at the high pH values 13 and 13.5.
