Heterogeneous Photocatalytic Degradation of Chlorophenols over Ag-TiO2 Nano Particles in an Aqueous Suspension
In the present work, TiO2 and Ag-TiO2 catalysts were prepared by an ultrasonic assisted sol-gel method. The physico-chemical characteristics studies of the newly synthesized catalysts were carried out by XRD, TEM, EDX, XPS, UV-Visible absorption spectra and an optical ellipsometry. In order to find out the optical absorption properties of the catalysts, theoretical simulations have been carried out by using the Tauc-Lorentz oscillator model. Photodegradation and mineralisation of the chlorophenols were confirmed by the HPLC and TOC measurements. The rate of a mineralisation trend was observed in the order of P < 2-CP < 2,4-DCP < 2,6-DCP < 4-CP < 2,4,6-TCP by using the Ag-TiO2 catalyst. The concentration of the main aromatic intermediate products was considerably lower for the Ag-TiO2 photocatalysts than for pure TiO2. This experiment demonstrated that the presence of Ag on TiO2 catalysts could enhance the photocatalytic oxidation of chlorophenols in an aqueous suspension. It was found that the degradation of the chlorphenols by these catalysts followed the pseudo- first order kinetic model.
Byung Tae Ahn, Hyeongtag Jeon, Bo Young Hur, Kibae Kim and Jong Wan Park
S. Rengaraj et al., "Heterogeneous Photocatalytic Degradation of Chlorophenols over Ag-TiO2 Nano Particles in an Aqueous Suspension", Solid State Phenomena, Vols. 124-126, pp. 1745-1748, 2007