H2O2 þ O H
!
H2O
þ
HO2
(2)
OH
þ OH
!
H2O2 (3)
HO2
þ
H2O2 ! OH
þ
H2O
þ
O2 (4)
2HO2
!
H2O2 þ
O2 (5)
HO2
þ OH
!
H2O
þ
O2 (6)
As the initial concentration of H2O2 is increased, the decolorization
rate is accelerated significantly, due to an increase in
available OH radicals in the solution [24]. As a result, there is a
critical hydrogen peroxide concentration for the RB181 bleaching
in UV/H2O2 process. The removal percent of dye in UV/H2O2
decolorization process at different hydrogen peroxide concentrations
is shown in Fig. 3.