Photodegradation mechanism of two dyes: the influence of adsorption behavior on the novel TiO2 particles.
The relationship between adsorption behavior and photocatalytic mechanism of the two dyes was investigated. Adsorption isotherms showed that the adsorption of cationic pink FG was Langmuir type behavior, while the reactive brilliant red k-2G was Freundlich type behavior. The increasing pH favored the adsorption of FG but have little effect on the photodegradation. The increasing pH favored the adsorption and the photodegradation of k-2G. The presence of scavenger of hvb+ and OH* radical potassium iodide inhibited the degradation of k-2G, free radicals scavenger tetranitromethane inhibited the photodegradation of FG. These results indicated that the photodegradation of FG mainly via free radicals in solution, and the photodegradation of k-2G was mainly on the catalysts surface or near the interface of solid and solution by react with hvb+ and surface-bound OH*. The different effect of SO4(2-), HCO3- on the adsorption and photodegradation of two dyes confirmed these results.
Li
Wei
W
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. weili819@yahoo.com
Wang
Yi-zhong
YZ
D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry*; D001639:Bicarbonates; D004396:Coloring Agents / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009282:Naphthalenesulfonates / Q000737:chemistry*; D010782:Photolysis; D011193:Potassium Iodide; D013431:Sulfates; D013774:Tetranitromethane; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical; D014961:X-Ray Diffraction
D001391:Azo Compounds; D001639:Bicarbonates; D004396:Coloring Agents; D005609:Free Radicals; D009282:Naphthalenesulfonates; D013431:Sulfates; D014874:Water Pollutants, Chemical; C472928:reactive bright red K2G; C009495:titanium dioxide; D011193:Potassium Iodide; D014025:Titanium; D013774:Tetranitromethane