In this paper, TiO2crystallines doped with transition metal ions have been prepared by sol-gel method. The UV-visible spectra indicated that the doping with transition metal ions (especially Cu2+, Mn2+and Cr3+ions) could effectively improve the absorption of TiO2crystals in the visible-light range. The XRD results showed that the doping does not affect the anatase phase of TiO2. The band structure and the UV-vis absorption spectrum of Mn2+ions doped-TiO2were also calculated by DFT (density function theory) method, which indicated that the doping with transition metal ion could make the band gap of TiO2smaller and a red shift in optical absorption.
In this paper, nano TiO2 loaded on activated carbon fiber(ACF) was prepared by hydrothermal method as TiO2/ACF photocatalytic.The material crystal structure, the superficial appearance of catalyst, were analyzed and measured by XRD and SEM images.Moreover, it used for photocatalytic oxidation As(Ⅲ).The effect of pH on the oxidation of As(Ⅲ) was studied. The oxidation of As(Ⅲ) efficiency increasing markedly with pH, and the catalytic efficiency is much higher in the alkaline environment than in the acidic environment.
There are many areas in the world where the ground water has been contaminated by arsenic. One process to purify the water is to use TiO2 to adsorb the arsenic. As the TiO2 surface can be cleaned and reused, it has a promising potential as a water purifier. In this paper, the plane-wave function method, based on the density functional theory, has been used to calculate the structures of arsenic(III) on a perfect TiO2 anatase (1 0 1) surface. All the arsenic(III) solution species such as H3AsO3, H2AsO3-1, HAsO3-2 and AsO3-3 are put onto the surface with many different possible structures to obtain the adsorption energy. Based on the adsorption energy, the bidentate binuclear (BB) adsorption configurations of arsenic(III) on the surface are more favorable at low concentrations, whereas BB form and monodentate mononuclear (MM) form may coexist at higher concentrations. The models and results fit well with published experimental results. The results and conclusions will be of benefit to further research on arsenite adsorption and its photocatalytic oxidation on a TiO2 surface.
There are many areas in the world where the ground water has been contaminated by arsenic. One process to purify the water is to use TiO2 to adsorb the arsenic. As the TiO2 surface can be cleaned and reused, it has a promising potential as a water purifier. In this paper, the plane-wave function method, based on the density functional theory, has been used to calculate the structures of arsenic(III) on a perfect TiO2 anatase (1 0 1) surface. All the arsenic(III) solution species such as H3AsO3, H2AsO3-1, HAsO3-2 and AsO3-3 are put onto the surface with many different possible structures to obtain the adsorption energy. Based on the adsorption energy, the bidentate binuclear (BB) adsorption configurations of arsenic(III) on the surface are more favorable at low concentrations, whereas BB form and monodentate mononuclear (MM) form may coexist at higher concentrations. The models and results fit well with published experimental results. The results and conclusions will be of benefit to further research on arsenite adsorption and its photocatalytic oxidation on a TiO2 surface.
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