3 research outputs found
Efficiency of iron(III)oxide in photocatalytic degradation of the fungicide metalaxyl
On the basis of quantitative 1 H NMR results we concluded that the photocatalytic degradation of the fungicide metalaxyl in the presence of Fe2O3 as photocatalyst, in the initial period, follows the first-order kinetics with reaction rate 4.4 times slower than with the TiO2 as photocatalyst.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200
Kinetics of photocatalytic removal of 2-amino-5-chloropyridine from water
Titanium dioxide sensitized photocatalytic degradation of a pyridine pesticide analogue, 2-amino-5-chloropyridine, was investigated by monitoring the pyridine moiety degradation, as well as by monitoring the chloride generated in the process. Effect of the initial substrate concentration on the rate of its degradation is reported. Here we show that the kinetics of both reactions are of the zero-order in the entire investigated concentration range. The Langmuir-Hinshelwood kinetic model successfully described the influence of the initial substrate concentration on the rate of the pyridine moiety degradation. It was found that dechlorination of the substrate takes place by direct photolysis. The differences in the kinetics of pyridine moiety degradation and dechlorination were explained on the basis of the electrostatic potential for the investigated compound
Photocatalytic activity of synthesized nanosized TiO2 towards the degradation of herbicide mecoprop
The kinetics and possible mechanism of the photocatalytic degradation of herbicide mecoprop, in UV illuminated aqueous colloids of synthesized nanosized TiO2 were investigated. The rate of degradation was studied by H-1 NMR, UV spectrometry, as well as by potentiometric titrimetric determination of generated chloride. The catalyst dosage and effects of other kinetic factors on the photocatalytic degradation, such as initial substrate concentration, temperature and type of TiO2 were investigated as well. The degradation rates were found to be strongly influenced by the above parameters. It was found that photocatalytic efficiency is lower and that a smaller number of observed organic intermediates (only 4-chloro-2-methylphenol and acetic acid) was detected than those observed in the presence of TiO2 (Degussa P-25). Kinetics of the degradation were also monitored for direct photolysis, as well as for solar degradation in the presence and in the absence of TiO2. (C) 2004 Elsevier B.V. All rights reserved