Hydrothermal Preparation Of Nano Titanium Dioxide Photocatalysis

Nanocrystalline TiO2 particles of anatase,tutile and mixture of them were prepared by hydrothermal method.The effects of different hydrothermal conditions on preparing anatase titania were investigated and the reaction mechanism was also discussed. The photocatalyze of samples on Methly orange and the effects of different conditions on photocatalyze were researched. The kinetic of photocatalytic degradation of Methly orange was studied.In the hydrothermal synthetical experiment, anatase titania of fine diameter and orbicular crystal was synthesized by Ti(SO4)2 and Na2CO3. Rutile and mix-crystal titania of fine diameter and orbicular crystal were synthesized by TiCl4.Optimizing the reaction conditions can well control the powder character.So the reaction time,temperature and concentration were investigated. The increasing of temperature and the prolonging of reaction time are good for orbicular crystal,but the particle diameter augmented. With the increasing of the concentration,the particle diameter decreased.The mechanism of hydrothermal reaction was discussed. The hydrothermal reaction was based on hydrolysis and the process of preparing nano titania abide 'dissolve-crystallize' mechanism. How to control different structure was studied and believed it is related to the character of the crystal structure and its circumstance.The photocatalyze of samples on Methly orange were researched and the performance of different samples on Methly orange was compared.The result is: mix-crystal is the best,and anatase is better than rutile. The effects on photocatalytic degradation reactions of different conditions were investgated. The kinetics of the photocatalytic degradation reaction of the of Methly orange was researched and believed it is a zero-order reaction at lower temperature: Ct=k't + A. Under different temperatures, the kinetic equation is different.