The use of oxyhalogen in photocatalytic reaction to remove o-chloroaniline in TiO2 dispersion

Photodecay of o-chloroaniline (o-CIA) in various combinations of UV sources, TiO2, and oxylialogens was investigated. To improve the conventional photocatalytic process by using UV/TiO2, the addition of oxyhalogens (ClO3-, BrO3- and IO3-) into UV/TiO2 system was studied and the effect in such addition is very encouraging for all the selected additives. Oxyhalogens are capable of deferring the electron-hole recombination of TiO2 which significantly improved its catalytic performance. The presence of IO3- in UV/TiO2 resulted in the fastest o-CIA decay among three oxhalogens at the same dosage. The decay of o-CIA in UV/TiO2/oxyhalogen process is characterized by a two-stage pseudo-kinetics, where a faster initial decay was followed by a retardation state. A mathematics model was successfully established for the prediction of the two-stage decay of o-CIA in UV/TiO2/IO3- with any designed [IO3-] concentration. (c) 2006 Elsevier Ltd. All rights reserved.