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

Photodecay of o-chloroaniline (o-ClA) in various combinations of UV sources, TiO2, and oxyhalogens was investigated. To improve the conventional photocatalytic process by using UV/TiO2, the addition of oxyhalogens (ClO3-,BrO3-andIO3-) 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-ClA decay among three oxhalogens at the same dosage. The decay of o-ClA 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  -ClA in UV/TiO2/IO3- with any designed [IO3-] concentration.