表面活性剂对TiO_2/Fenton复合体系可见光催化活性的增强效应

Enhancement of Visible-Light Photocatalytic Activity of TiO_2/Fenton Composite System Induced by Surfactant

在pH 3.0缓冲体系中,紫外光作用下,采用TiO2/Fenton复合体系催化氧化吖啶橙(AO)染料具有较高的催化效率,而在可见光作用下催化活性极低.通过引入表面活性剂十二烷基磺酸钠(SDS),可见光条件下的催化效率得到极大提升,反应30 min后降解率达到91.8%.依据染料吸附模型以及可见光敏化催化机理解释,SDS的作用主要在于增强了染料分子与Fenton试剂在TiO2粒子表面的作用能力,使两类反应能够有效地协同进行,共同作用于染料的分解.

Photooxidation of an objective compound acridine orange dye （AO） was investigated by using TiO2/Fenton composite system. In the system with pH 3.0, high photocatalytic efficiency was obtained under UV light irradiation. On the contrary, the photocatalytic activity was very limited under visible light irradiation. Through the introduction of surfactant sodium dodecyl sulfate （SDS）, the photocatalytic efficiency could be significantly increased and ultimately the conversion rate could be 91.8% after 30 min irradiation. Based on the dye adsorption model and visible-light sensitized mechanism, the function of SDS is presumed to be attributed to the enhancement of interaction between TiO2 nanoparticles and other molecules （such as dye molecules, intermediate products, and Fenton reagent）. In this way, Fenton reagent played a positive role as competitors in the whole photocatalytic reaction through improving the efficiency of electron transfer from the excited dye molecules to the conduction band of TiO2 as well as Fe^3＋ ions. In conclusion, the synergistic effect of the two types of reaction occurred in the system in the presence of SDS and made significant contribution to the degradation of dyes.