The Removal Of Atrazine In Water By Catalytic Ozonation In The Presence Of Nano-TiO₂ Catalyst

Nanometer titanium dioxide was prepared by the sol-gel method, and the catalysts with different crystals which were calcined at different sintering temperatures were characterized by XRD, Raman spectroscopy, TG-DSC, FTIR, TEM, Zeta potential and XPS. The various characterization methods showed the catalytic activity of nanometer titanium dioxide and provided the effective theory basis for the experiment.Electron paramagnetic resonance technique and fluorescence spectrophotometry were used to test the hydroxyl radicals (· OH) in the sole ozonation and catalytic ozonation system, the results showed that more · OH was produced in the catalytic ozoation system compared with sole ozonation system. Under the different testing conditions, the results received by the fluorescent photometric method showed that the most·OH was produced in the catalytic ozonation system with the catalyst calcined at 700℃, and the production of · OH increased with the increase of catalyst dosage and liquid ozone concentration. And the higher pH in the solution, the higher production of · OH was get in the catalytic ozonation system.The effect of the catalyst crystal structure, solution pH, ozone dosage, catalyst dosage and initial concentration of atrazine on the degradation rate was probed by using the catalytic ozonation in the presence of nanometer titanium dioxide catalyst into dealing with atrazine simulation wastewater. The results showed that, under the same condition, the rutile titanium dioxide exerted better activity than the anatase titanium dioxide in the catalytic ozonation system and the catalyst calcined at 700℃ showed the best degradation rate which reached 100%. Furthermore, the degradation rate of atrazine increased with the increase of the solution pH, ozone dosage and catalyst dosage. However, the initial concentration of atrazine had less effect on the degradation rate of atrazine.De-alkyl process occurred in both sole ozonation system and catalytic ozonation system, and more thorough degradation of atrazine and more various products was received in catalytic ozonation system than in sole ozonation system, including de-alkyl, de-chlorination and de-amination processes. In the luminescent bacteria inhibition experiment, the degradation products in catalytic ozonation system showed lower toxicity compared with sole ozonation system.