钛基废水处理光催化剂.pptVIP

Titania Based Photocatalysts for Wastewater Treatment SeminarⅠ Pollutant treatment by Photocatalysis on TiO2 J. M. Herrmann Topics in Catalysis Vol. 2005, 34, 49 Serpone, N.; et al. J. Photochem. Photobiol. A: Chemistry, 1995, 85, 247-255 1.Have strong photocatalytic oxidation and reduction abilities Characteristics of TiO2 as Photocatalyst Characteristics of TiO2 as Photocatalyst TiO2 is biologically and chemically inert TiO2 is stable with respect to photocorrosion and chemical corrosion: Eeg(3.2eV)2.8eV(OH-=·OH + e- ; E0 = 2.8V) TiO2 is inexpensive and easy of availability Hoffmann, M. R.; Martin, S. T.; Choi, W. Y.; Bahnemann, D. W. Chem. Rev. 1995. 95. 69-96 The types of TiO2 Properties Rutile Anatase Brookite Crystalline form Tetragonal system Tetragonal system Orthogonal system Density(g/cm3) 4.27 3.90 4.13 Melting point (0C) 1825 Transformation to rutile Transformation to rutile Band gap(eV) 3.0 3.2 Sclafani A, Palmsano L, Schiavello M. J. Phys. Chem. 1990, 94: 829~832 Anatase and Rutile CB/e- VB/h+ CB/e- VB/h+ 3.2eV 3.0eV 0.2eV Sclafani A, Palmsano L, Schiavello M. J. Phys. Chem. 1990, 94: 829-832 The two types of TiO2 have a same oxidative power The reducing power of the anatase type is stronger than that of the rutile type Photocatalytic Oxidation of Aqueous Inorganics J.M. HERRMANN et al, J. Phys. Chem. 1986, 90, 6028 Heavy metal removal J.M. HERRMANN et al , J. Catal. 1988,113,72 Photocatalytic Oxidation of Aqueous organics In water, UV-irradiated titania is able to generate OH0 radicals: Hoffmann, M. R.; Martin, S. T.; Choi, W. Y.; Bahnemann, D. W. Chem. Rev. 1995. 95. 69-96 Characteristics of Titania Photocatalyst for Wastewater Treatment Total mineralization of aqueous pollutants( into CO2, H2O, Cl-, NO3-, SO42-, HPO42-….) Wide applicability (many pollutants treated) Safety of the process (harmless TiO2 catalysts, no chemical additives to water) Process active at room temperature: no need of thermal energy for hea