Thesis (Ph.D.)--Chulalongkorn University, 2009

In this study, a new tungsten-doped titanium dioxide photocatalyst with hydrothermal treatment has been developed and tested for its photocatalytic activity by using 2-chlorophenol as the target compound. The synthetic procedure and optimum conditions were described in details. This photocatalyst could be effectively activated by blue-light irradiation and its activity was almost comparable to those of the commercial Degussa P-25 under ultraviolet irradiation. 2-chlorophenol at 0.01 mM could be removed completely in 120 and 90 minutes by the photocatalysis using 0.5% by mole tungsten-doped titanium dioxide with hydrothermal treatment under blue-light irradiation and the P-25 under ultraviolet irradiation, respectively. Crystalline structure which is a very important factor controlling the response behavior of the titanium dioxide under ultraviolet irradiation did not have any significant effect under visible-light irradiation. Photocatalytic kinetics of 2-chlorophenol oxidation by the 0.5% tungsten-doped titanium dioxide with hydrothermal treatment under blue-light irradiation could be sufficiently explained by the Langmuir-Hinshelwood model with k[subscript r] and K of 3.00x10⁻⁴ mM/min and 239.13 1/mM, respectively.