水溶液中纳米二氧化钛光催化降解甲基橙的影响因素(英文)

INFLUENCING FACTORS OF PHOTOCATALYTIC DEGRADATION OF METHYL ORANGE BY NANOMETER TITANIUM DIOXIDE IN AQUEOUS SOLUTIONS

用沸腾回流直接水解法制备了粒径为25～35nm纯锐钛矿型纳米二氧化钛(TiO_2)。用X射线衍射和透射电镜表征材料的结构与形貌。用该催化剂催化降解甲基橙,研究了催化剂用量、甲基橙的起始浓度、溶液pH值、光强度、溶液中添加金属离子的影响。结果表明:在较强紫外光照射下,当甲基橙的起始浓度为0.02g/L,TiO2用量为1.0g/L,光催化效率最高。酸性条件有利于光催化降解甲基橙。掺加Fe^(3+)或Zn^(2+)的光催化效率显著增加。掺加Mn2+或Ca2对光催化活性没有影响。在紫外光区域(366nm),样品对催化降解水溶液中甲基橙的活性较高。

Pure anatase phase titanium dioxide（TiO2） with 25-35 nm grain size was prepared by direct hydrolysis under boiling reflux conditions. The structure and morphology of the materials were characterized by X-ray diffraction and transmission electron microscope. This catalyst was used for the photocatalytic degradation of methyl orange. The effects of the catalyst loading, initial concentration of methyl orange, pH value, light intensity, and addition of metal ions in solution were investigated. Experimental results indicate that the photocatalytic efficiency is best when the initial concentration of the methyl orange is 0.02 g/L, the loading concentration of TiO2 is 1.0 g/L and the UV irradiation is at a higher light intensity. Acidic medium accelerated the photocatalytic degradation rate of methyl orange. The degradation rate increased considerably with the addition of Fe^3＋ or Zn^2＋. The effects of the addition of Mn^2＋ and Ca^2＋ on the photocatalytic activity were not notable. The specimen showed good photoactivity upon the degra-dation of the methyl orange in aqueous solution in the ultraviolet range （366 nm）.