Abstract:
A nanothinfilm TiO2 synthesized by sol-gel process with addition of diethanolamine
was used to study the photocatalytic treatability of several species of halogenated phenol
from water. The halogenated phenol investigated in this work included 2-chlorophenol,
2-bromophenol, 2-fluorophenol, meta-chlorophenol, para-chlorophenol, 2,4-dichlorophenol,
2,4,6-trichlorophenol. The photocatalytic degradation rates, Langmuir-Hinshelwood kinetic
constants, half life of all pollutants under UV exposure were determined. Concerning type of
halogen species attached on the phenol, photocatalytic degradation rate was found in the order
of 2-fluorophenol > 2-chlorophenol > 2-bromophenol. In addition, para- and ortho-chlorophenols
provided highest degradation rate than meta-chlorophenol. The photocatalytic degradation rate
decreased with the increase of chlorine atoms in phenol as represent by 2-chlorophenol > 2,
4-dichlorophenol > 2,4,6-trichlorophenol. No intermediates were observed for all phenol
degradations except para-chlorophenol degradation in which hydroquinone was detected.
The different molecular structure of phenol was the major factor causing the difference in
photocatalytic degradation rate in this work.