Abstract:
Nowadays, environmental pollution is induced by the release of persistent dyes from
industries. Orange fruits have a relatively short shelf-life of only 3-5 days at room
temperature, and conventional packaging methods, such as paper or plastic, can only
extend their shelf-life to 7-10 days. To overcome the limitations of previous approaches, it
is necessary to explore new solutions that prevent secondary pollution and reduce the
spoilage of fruits. Researchers have tried to use various advantages of metal oxide
nanoparticles (MONPs) to overcome these problems. We have been attempting to
overcome problems associated with the ZnO-NPs via the preparation of its NP materials
with other metal oxide and doping with appropriate types of nonmetals. This study was to
prepare ZnO NPs with low energy band gaps like Cu and dope them with S to further
enhance their photocatalytic properties and extend the shelf-life of orange fruit. The
synthesis of Cu & S-ZnO NPs has been carried out sol-gel method. The synthesized NPs
were characterized by UV-Vis, XRD, SEM, and FT-IR. The energy band gap information
from UV-Vis characterization shows that the successive decrement values, 3.07 eV, 2.94
eV, 2.80 eV, and 2.59 eV are for ZnO NPs, Cu-ZnO NPs, S-ZnO NPs, and Cu & S-ZnO
NPs respectively. The XRD characterization shows that the synthesized samples were
highly crystallized. The SEM image of ZnO NPs shows that the shape of the nanoparticle is
rod-shaped whereas a spherical shape was observed for Cu-ZnO NPs, S-ZnO NPs, and Cu
& S-ZnO NPs. The photocatalytic performance of the nanomaterials was evaluated by
their ability to degrade methylene blue dye. The photocatalytic efficiency of 0.06 g/L of
catalytic dose per 10 mg/L dye solution at pH=11 was 99 %, 96.7% 92.6%, and 89.7%
for, Cu &S-ZnO NPs, S-ZnO NPs Cu-ZnO NPs, and ZnO NPs, respectively. Furthermore,
the shelf-life of Orange fruits was significantly extended when treated with the Cu &S-ZnO
NPs, demonstrating their potential for use in orange fruit preservation.
