ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 12, pp. 1985−1990. © Pleiades Publishing, Ltd., 2016.
The text was submitted by the authors in English.
One of the most important problems of the last century
is environmental pollution according to technological
developments. Industrial use of phenolic compounds
and their products over the last decades has led to the
environmental pollution. These compounds are toxic
and carcinogenic and they can persevere for a long
time in the environment because of their resistance to
microbiological remediation .
Advanced oxidation processes (AOPs), which are
an in situ production of highly chemical oxidants such
as hydroxyl radicals, have appeared as a main class of
technologies to accelerate the non-selective oxidation
. 4-Chloro-2-nitrophenol (4C2NP) is a toxic pollutant
that is extended in the environment, including ground
water and soil . The wastewater containing 4C2NP
should be treated before discharge to the environment.
The conventional treatment methods used for the removal
of phenolic compounds are not pleasing according to the
high stability and solubility of phenolic compounds in
water. In recent years, many advanced treatment methods
[4‒8] have been employed for the degradation of phenolic
compounds in wastewater. Moreover, microwave (MW)
irradiation can be operative because it has localized
higher energy densities and constant intense heating .
The activation energy was decreased by the nonthermal
effect of absorbed MW energy and the chemical bond
of the pollutants in a solution was weakened . The
energy of MW has been reported to be sufﬁ cient to break
the chemical bonds of several organic compounds .
Microwave can be used along with hydrogen peroxide
and photo catalyst and the combined system can give
better results for the degradation of organic pollutants
because MW and photo catalyst had a same mechanism
for generating hydroxyl radicals from water.
In this study, degradation of 4C2NP by MW irradiation
was investigated for the ﬁ rst time. A novel method based
on the use of MW and UV in the presence of catalyst
was used for increasing the degradation efﬁ ciency.
The combined method including UV/MW/TiO
increase the amount of radical generation and removal
of 4C2NP. The energy requirements for the microwave
and UV operations can be reduced by combining because
Using Microwave along with TiO
of 4-Chloro-2-nitrophenol in Aqueous Environment
Aref Shokri* and Ali Hassani Joshagani
Young Researchers and Elite Club, Arak Branch, Islamic Azad University, Arak, Iran
Department of Chemical Engineering, Faculty of Technical Engineering, Arak Branch, Islamic Azad University, Arak, Iran
Received September 2, 2016
Abstract—In this project, microwave (MW) irradiation, photolysis, and photo catalyst were used for degradation
of 4-chloro-2-nitro phenol (4-C2NP) in aqueous environment. The inﬂ uence of main operating parameters such as
initial pH, initial concentration of 4C2NP, power dissipation and the dosage of TiO
on the degradation efﬁ ciency
has been investigated. The optimum conditions was obtained such as initial concentration of 4C2NP at 30 mg L
initial pH at 6, power dissipation at 16 W for UV irradiation, and the amount of TiO
at 0.2 g L
. The removal of
4C2NP and chemical oxygen demand (COD) after 100 min of reaction in the combined method (MW/UV/TiO
obtained as 80.5% and 47.3%, respectively. Almost all processes are followed from the pseudo ﬁ rst order kinetics
and the degradation rate of 4C2NP obeyed the following order: UV/TiO
/MW > UV/TiO
> MW/UV > UV>MW.