改性TiO_2光催化降解三苯甲烷类污染物

Photocatalytic degradation of triphenylmethanes in vis/TiO_2 suspension system

以硫酸钛为原料采用水热法制备了掺Fe3+TiO2晶体粉末,采用X射线衍射仪(XRD)对样品的结构进行了表征。在可见光条件下,用溴酚蓝、甲基绿、甲基蓝、孔雀石绿、甲基紫和碱性品红等6种典型三苯甲烷类化合物为目标降解物,研究了以自制的掺Fe3+TiO2晶体粉末对它们的催化降解作用。实验结果表明,制备的掺Fe3+TiO2晶体属于锐钛矿型。6种化合物的光催化降解反应遵循拟一级动力学规律,且可用Langmuir-Hinshelwood(L-H)动力学模型描述,其表观反应速度常数(k)的大小顺序为:溴酚蓝<甲基绿<甲基蓝<孔雀石绿<甲基紫<碱性品红,大小变化次序与其半衰期t1/2成反比,并从分子结构上对它们的降解规律进行定性解释。

Fe3＋-doped TiO2 crystal powders were prepared by hydrothermal method with titanium sulfate as raw materials.The samples were characterized using XRD.Photocatalysed degradation of triphenylmethanes（bromophenol blue,methyl green,methyl blue,malachite green,methyl violet and basic fuchsin） in vis/TiO2 suspension system was studied.The experiment results show that the as-prepared TiO2 crystals are anatase.The reaction of photocatalysed degradation obeys pseudo first-order kinetics and is represented by the Langmuir-Hinshelwood（L-H） kinetic model.The observed rate constants（k） are in this order： bromophenol blue 〈methyl green 〈 methyl blue 〈 malachite green 〈 methyl violet 〈 basic fuchsin,which is contrary to their half life（concentration）,and the rule of photocatalysed degradation is interpreted qualitatively from their molecular structure