The Tio <sub> 2 </ Sub> Photocatalytic Degradation Of The Trials And Mechanistic Studies Of Methyl Orange

Photocatalytic oxidation technology is a new-style wastewater treatment technology, whose virtues are high treatment efficiency, simple technics equipment, operating condition controlling easily, degradation organics pollution without selectivity and without second pollution. The beginning of the photocatalytic oxidation technology starts the new phase of dyes wastewater degradation. In this experiment, Methyl Orange was the study object and anatase TiO2 was the photo catalyst. The main contents of experiment were as follows:This paper reviewed the effects of pH value, solution initial concentration and TiO2 supply on the photocatalytic oxidation MO. That was to say the effects of the three factors on the rate of MO decolorization and the produce rate of SO42-. The effect of pH value on the rate of MO decolorization was much distinct, the rate of MO decolorization in the acid solution was bigger than that in the alkaline and neutral solution. The more of the solution initial concentration, the more of the MO reaction amount in unit time. When the solution initial concentration was bigger than 20mg/L, the reaction amount in unit time keep steadiness. The rate of MO decolorization became bigger and bigger, when the TiO2 supply rose from 0.2mg/L to 0.8mg/L. When the TiO2 supply was more than 0.8mg/L, the rate of MO decolorization became lower and lower. 0.8mg/L TiOi met the command of the experiment. Produce rate of SO42" were made in the same conditions. Produce rate of SO42" were lower than the rate of MO decolorization. Compared the effects of powder and film TiOa on the rate of MO decolorization. The rate of MO decolorization by the powder TiO2 is better.The main problem of photocatalytic degradation dyes was to know the intermediates little. There were few detailed reports about the photocatalytic process. Studied the intermediates by means of ultraviolet-visible spectrophotometer, high performance liquid chromatogram instrument, and chromatogram-mass spectrum instrument. Groped the chromatogram separating condition, including columninseparating model, wavelength, column temperature and additive. Then selected the optimize parameters and optimized target, planed the experiment, found the best separating condition. At the last, obtained the conclusion by analyzing the mass spectrum of samples. Discussed the MO photocatalytic degradation mechanisms. MO had two configurations, so it might have two different photocatalytic degradation courses. In each course, some intermediates accorded with the results of mass spectrum, which were the evidence of the probability and reasonability of the two courses.This experiment chose the MO as the experiment object, by means of ultraviolet-visible spectrophotometer, high performance liquid chromatogram instrument, and chromatogram-mass spectrum instrument, studied the effects of the main factors on the rate of MO decolorization and the produce rate of SO42". Analyzed the intermediates change during the MO photocatalytic degradation. Discussed the mechanisms of MO photocatalytic degradation. So that optimize reaction system conditions, improve the photocatalytic efficiency, offer some useful parameters to the industrialization application, magnify the experiment and realize the industrialization operation in the future.