4. Conclusion
The treatment of a solution containing DB71 by the Fenton
oxidation process has been taken into consideration in this
study. The experimental results show that the initial concentration
of H2O2, Fe2+, DB71, the initial pH, and the temperature
had great influence on the degradation of DB71 dye by the
Fenton’s process. The optimal values of operating parameters
during the oxidation of the DB71 dye by the Fenton’s process
are Fe2+ =3 mg L1, H2O2 =125 mg L1, pH = 3.0 and
increasing temperature had a positive effect on the DB71 degradation.
As is known, complete decolorization of the dye does
not mean that the dye is completely degraded, so the degradation
of DB71 in terms of COD removal was also investigated.
As can be seen from the Figs, COD values decreased with optimum
parameters. The initial COD of 139.9 mg L1 DB71 was
68.9 mg L1, after treatment by AOP. This is because the intermediate
products of DB71 by AOP are difficult to oxidize, and
complete oxidation may proceed in a longer time. The BMG
kinetic model provided the best correlation of the used experimental
data compared to the pseudo-first and second-order
kinetic models. Spectral analyses have indicated that the
destruction rate of the azo linkage in the azo dyes during the
Fenton process is higher than that of benzene and naphthalene
rings.
This process can be used to treat water discharge containing
dyes such as DB71. The Fenton process is very suitable for the
treatment of colored waters, very effective and less expensive
than conventional processes.