摘要:
采用溶胶-凝胶法制备纳米粉末TiO2,运用XRD技术对样品进行了表征.以中压汞灯为光源,在圆柱型石英光催化反应器上进行了酸性黑染料光催化反应性能考察.讨论了煅烧温度、空气流量、试液的pH值、光照时间与酸性黑染料光催化降解率的关系.实验结果表明,煅烧温度使TiO2光催化性能得到显著改善.TiO2在400℃煅烧3h,XRD曲线上出现宽化锐钛矿型衍射峰;到500℃,所有晶粒均为锐钛矿型结构,随着煅烧温度升高,晶粒中金红石型含量相应增加;到750℃,粉末中的所有晶粒均为金红石型结构.但是对于同一煅烧温度,煅烧时间不同,晶型不发生变化.煅烧温度为600℃时,TiO2光催化活性最高.在优化实验条件下,光照140min,酸性黑染料光催化降解率达到100%.
Abstract:
TiO2 nanometer particles were prepared by the sol-gel process and characterized by X-ray diffraction (XRD). Photocatalytic decomposition of acid black dyes was investigated in a cylinder type photoreactor made of quartz glass using a middle-pressure Hg lamp as the light source, The effects of the calcination temperature, flow rate of air, pH of solution and illumination time on the photodegradation rate of acid black dyes were discussed. The results showed that the calcination temperature greatly enhanced the photocatalytic property of TiO2, Calcining the powders in air at 400℃ for 3 h, the broad peaks of anatase type on the curves of XRD patterns of TiO2 appeared. Calcining the powders in air at 500℃ for 3 h, all crystal particles in TiO2 changed the structure of anatase type, and the content of rutile type increased gradually along with the calcination temperature rising. Calcining the powders in air at 750℃ for 3 h, all crystal particles in TiO2 turned into the structure of rutile type. However, the crystal type of TiO2 did not change along with the calcination time prolonging at the same temperature. The photocatalytic activity of TiO2 was the highest while calcining TiO2 at 600℃ for 3 h. Under the optimum conditions, the photocatalytic degradation rate of acid black dyes reached 100% with the illumination time of 140 min.
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