Density Functional Theory Calculations of Arsenic(V) Structures on Perfect TiO2 Anatase (101) Surface

Arsenic is a common contaminant in drinking water supplies and TiO2 has been developed to effectively remove arsenic from polluted water during recent years. In this paper, the plane-wave function method, based on density functional theory, has been used to calculate the structures of arsenic(V) on the perfect TiO2 anatase(1 0 1) surface. All the possible arsenic(V) species such as H2AsO4-1, HAsO4-2 and AsO4-3 are put onto the surface with many possible structures to obtain the adsorption energy. Based on the adsorption energy, the bidentate binuclear (BB) surface complexes are more favorable at low coverage, whereas BB complex and monodentate mononuclear (MM) complex may coexist at high coverage. The models and results fit well with the experimental results. Some conclusions are helpful for the understanding and further exploration of arsenate adsorption properties on TiO2 surface.