TY - JOUR
T1 - Theoretical studies of arsenite adsorption and its oxidation mechanism on a perfect TiO 2 anatase (1 0 1) surface
AU - Wei, Zhigang
AU - Zhang, Shaowen
AU - Pan, Zhanchang
AU - Liu, Yue
PY - 2011/11/15
Y1 - 2011/11/15
N2 - There are many areas in the world where the ground water has been contaminated by arsenic. TiO 2 is one of the most promising materials that can remove arsenic from groundwater supplies by the adsorption-based processes. The TiO 2 surface is capable of photo-catalytic oxidation (PCO) changing the arsenite [As(III)] to arsenate [As(V)] which is more easily absorbed by the surface, increasing the efficiency of the process. In this paper, a density functional theory calculation has been performed to investigate the adsorption of As(III) on a perfect TiO 2 anatase (1 0 1) surface. All the As(III) solution species such as H 3 AsO 3 , H 2 AsO 3 - , HAsO 3 2- and AsO 3 3- are put onto the surface with many different possible attitudes to obtain the adsorption energy. Based on the adsorption energy and the concentration of H 3 AsO 3 , H 2 AsO 3 - , HAsO 3 2- and AsO 3 3- in an aqueous solution, the bidentate binuclear (BB) adsorption configurations of H 2 AsO 3 - on the surface are more favorable at low As(III) concentrations, whereas BB form and monodentate mononuclear (MM) form may coexist at higher concentrations. By calculating H 2 AsO 3 - co-adsorption with water and oxygen, we can confirm the deep acceptor character of an adsorbed O 2 molecule which implies that surface superoxide (or hydroperoxyl radical) plays an important role during the PCO process of As(III) on TiO 2 surface.
AB - There are many areas in the world where the ground water has been contaminated by arsenic. TiO 2 is one of the most promising materials that can remove arsenic from groundwater supplies by the adsorption-based processes. The TiO 2 surface is capable of photo-catalytic oxidation (PCO) changing the arsenite [As(III)] to arsenate [As(V)] which is more easily absorbed by the surface, increasing the efficiency of the process. In this paper, a density functional theory calculation has been performed to investigate the adsorption of As(III) on a perfect TiO 2 anatase (1 0 1) surface. All the As(III) solution species such as H 3 AsO 3 , H 2 AsO 3 - , HAsO 3 2- and AsO 3 3- are put onto the surface with many different possible attitudes to obtain the adsorption energy. Based on the adsorption energy and the concentration of H 3 AsO 3 , H 2 AsO 3 - , HAsO 3 2- and AsO 3 3- in an aqueous solution, the bidentate binuclear (BB) adsorption configurations of H 2 AsO 3 - on the surface are more favorable at low As(III) concentrations, whereas BB form and monodentate mononuclear (MM) form may coexist at higher concentrations. By calculating H 2 AsO 3 - co-adsorption with water and oxygen, we can confirm the deep acceptor character of an adsorbed O 2 molecule which implies that surface superoxide (or hydroperoxyl radical) plays an important role during the PCO process of As(III) on TiO 2 surface.
KW - Absorption
KW - Adsorption
KW - Arsenite
KW - Density functional theory
UR - http://www.scopus.com/inward/record.url?scp=80455176957&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2011.09.069
DO - 10.1016/j.apsusc.2011.09.069
M3 - Article
AN - SCOPUS:80455176957
SN - 0169-4332
VL - 258
SP - 1192
EP - 1198
JO - Applied Surface Science
JF - Applied Surface Science
IS - 3
ER -