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Advanced approach for degradation of recalcitrant by nanophotocatalysis using nanocomposites and their future perspectives
Padmanaban, V. C.; Giri Nandagopal, M. S.; Madhangi Priyadharshini, G.; Maheswari, N.; Janani Sree, G. & Selvaraju, N.
Abstract
Industrial effluents containing persistent pollutants
play a significant role in environmental pollution.
Classical techniques such as chlorination, coagulation, ion
flotation, membrane process and sedimentation that have
been used to decontaminate polluted water are incapable of
efficient degradation due to the generation of secondary
pollutants. Photocatalysis, an advanced oxidation process
in which the photoreaction is accelerated by the irradiation
of catalyst, has shown efficient degradation of recalcitrant
in water system. Usage of nanoparticles as homogenous
photocatalyst has become prevalent due to their improved
properties such as large surface-to-volume ratio, controlled
uniform particle size and its composition which enhances
the degradation rate. The recombination of holes and
electron pair which is considered to be the limitation in
homogenous system can be overcome by nanocomposites
or heterogeneous photocatalysts. This system decreases the
rate of recombination, leading to effective degradation of
individual pollutants because of their enhanced physicochemical
and structural properties. In recent years,
heterogeneous nanophotocatalytic processes employing
titanium dioxide (TiO2) and zinc oxide (ZnO) composites
have gained immense research interest as an effective
wastewater treatment method because of its efficacy in
decomposing and mineralizing the hazardous organic and
inorganic pollutants utilizing the UV and visible photons.
This paper reviews about the process, synthesis and
parameters influencing photocatalytic reaction and their
kinetics with much emphasize on types of nanoparticles
and nanocomposites and its application in wastewater
treatment.
Keywords
Degradation; Nanocomposites; Photocatalysis; Titanium dioxide (TiO2); Zinc oxide (ZnO)
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