Photo-catalysis Degradation Kinetics of Modified Titanium Dioxide to Malachite Green under UV-light

Modified titanium dioxide powders are prepared via hydrothermal method and were characterized by means of XRD,kinetics of as-prepared photo-catalyzer photo-catalyzing malachite green are researched by analysis of the influence of the malachite green initial concentration,the p H value,the catalyst dosage and the amount of iron-doping in titanium dioxide on photo-catalytic degradation speed. The results show that the decolorization rate D%( 80. 11%) and degradation observed rate constant k( 0. 3196 h- 1) of malachite green achieve maximum under follow conditions: a malachite green's initial concentration 2 mg /L( p H = 9),a catalyst dosage 1. 6 g / L,an amount of iron-doping 8%( mole fraction),and an irradiating with ultraviolet light( λ = 365 nm) time 4 h at room temperature. The photo-catalytic degradation of malachite green conforms to the rule of Langmuir-Hinshelwood( L-H) kinetics and follows the first-order reaction.