The exploration of new treatment processes for efficient degradation of pharmaceuticals and
personal care products (PPCPs) has become a quintessential challenge worldwide due to
inefficiency of conventional wastewater treatment plants in their degradation. Alternatively,
the TiO
2−based photocatalysis process has shown considerable potential for pollutant
degradation due to its key features, viz., (a) ability to completely degrade recalcitrant pollutants,
and (b) ability to mineralize organic pollutants into carbon dioxide and water. Nevertheless, its
practical applicability is mainly restricted due to: (a) the ability to exploit UV light (2−3% of
the solar spectrum) only, and (b) the difficulty in separation after use. To overcome the
challenges in the separation of TiO
2−based p...[
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The exploration of new treatment processes for efficient degradation of pharmaceuticals and
personal care products (PPCPs) has become a quintessential challenge worldwide due to
inefficiency of conventional wastewater treatment plants in their degradation. Alternatively,
the TiO
2−based photocatalysis process has shown considerable potential for pollutant
degradation due to its key features, viz., (a) ability to completely degrade recalcitrant pollutants,
and (b) ability to mineralize organic pollutants into carbon dioxide and water. Nevertheless, its
practical applicability is mainly restricted due to: (a) the ability to exploit UV light (2−3% of
the solar spectrum) only, and (b) the difficulty in separation after use. To overcome the
challenges in the separation of TiO
2−based photocatalysts, in this research, magnetic separation
was ensured by infusing the superparamagnetic core−shell Fe
3O
4@SiO
2 nanoparticles with the
photocatalysts. The visible light activity of TiO
2 was achieved by its non−metal doping,
wherein nitrogen (N) was doped into the TiO
2 lattice. Thus, a visible–light–driven magnetically
separable N−TiO
2/Fe
3O
4@SiO
2 nanophotocatalyst was developed by a sol−gel method which
was able to degrade various PPCPs, viz., ibuprofen, benzophenone−3, and carbamazepine. Due
to the appealing features of heterojunction photocatalysis for PPCP degradation, two visible–light–driven magnetically recyclable direct contact Z–scheme heterojunction nanophotocatalysts, namely g−C
3N
4/TiO
2/Fe
3O
4@SiO
2 and TACN/TiO
2/Fe
3O
4@SiO
2, were
developed and were able to generate the powerful •OH radical, resulting in enhanced
degradation of various recalcitrant PPCPs in real sewage effluent. The newly developed
nanophotocatalysts were characterized by various techniques, viz., BET surface area analyzer,
SEM, TEM, UV–vis DRS, VSM, XRD, and XPS. Furthermore, the nanophotocatalyst’s
reusability, the effect of different pH values (3, 5, 7, 9, and 11) and solution matrixes, the role
of the dominant reactive species, and mineralization were also investigated for the PPCP
degradation. Overall, the recyclable nanophotocatalysts were found to be a good choice for
practical environmental applications.
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