Abstract:
Many types of dyes are used in textile industries and the contaminated water is
expelled as it is without any treatment for the removal of dyes and harmful reagents
which pose threats to human and animal health because some dyes are dangerous to
chronic level. They have many short-term impacts such as skin sensitization and
nausea to lingering impacts like cancer. Photocatalysis is an advanced technique from
nanochemistry having many applications in daily life which cover areas from clean
energy production and self cleaning surfaces to environmental protection. In this
research, TiO2 and graphite were used for the preparation of TiO2 nanotubes and
graphene oxide, respectively. TiO2 nanotubes were prepared by hydrothermal method
and Hummers’ method was used for the graphene oxide synthesis. Co-doping of
cobalt and nitrogen was done on TiO2 catalysts which resulted in narrowing of band
gap with increase in efficiency and thus making the process more economical. Urea
and cobalt nitrate were used as nitrogen and cobalt dopant precursors, respectively.
Nitrogen concentration was kept constant and cobalt was taken in 4 different
concentrations i.e 0.2, 0.4, 0.6 and 0.8 g. The obtained catalysts were characterized by
FT-IR, DRS, SEM, TGA, BET, XRD and EDX for the investigation of attached
functional groups, band gap, morphology, thermal stability, surface area, phase and
composition, respectively. Additionally the effects of doped amount of cobalt ions on
the optical properties and photocatalytic activity of co-doped TiO2 nanotubes were
investigated. Methyl orange was selected for the degradation study. The results
exhibited that photocatalytic performance of 4-CoN-TNT is best amongst all in the
visible light. It shows efficiency of 88%. To further improve the efficiency the best
catalyst was selected for the nanocomposite preparation with reduced graphene oxide.
Hydrothermal method was used for nanocomposite formation and in situ reduction of
graphene oxide was carried out. Again the degradation study was carried out against
methyl orange. The efficiency was increased up to 93%.
