English abstract
Pharmaceutical compounds in wastewater are a concerning issue. Pharmaceutical wastes
cause harmful effects even at low concentrations. This thesis is to investigate the
degradation of the pharmaceutical wastes by the photocatalysis process using silver
nanoparticles (Ag NPs) decorated zinc oxide (ZnO) nanorods. ZnO nanorods were first
synthesized on glass substrate by microwave hydrothermal method. Silver nanoparticles
were subsequently deposited on ZnO nanorods by photodeposition technique. Different
concentrations of silver nitrate were used and optimized. In addition, effect of annealing
temperatures and environments upon silver nanoparticles formation on ZnO NRs were
investigated. The synthesized Ag-ZnO nanostructures were characterized by X-ray
diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy
dispersive X-ray analysis (EDXA), transmission electron microscopy (TEM), X-ray
photoelectron spectroscopy (XPS), UV-visible absorption spectroscopy (UV-Vis), and
photoluminescence (PL) spectroscopy. XRD, FE-SEM and TEM results confirm that
ZnO nanorods have hexagonal wurtzite crystal structure with Ag nanoparticles were
successfully attached on ZnO nanorods. XPS results confirm the presence of metallic
silver in Ag-ZnO nanostructures. PL results provide an effective separation of
photogenerated electron-hole pairs in the Ag-ZnO nanostructures when compared to the
pristine ZnO nanorods. UV-visible absorption spectroscopy shows enhance optical
absorption in the visible region due to the surface plasmon resonance properties of Ag
nanoparticles. The Ag-ZnO nanostructures were used as catalysts for the
photodegradation of pharmaceutical compounds (paracetamol and amoxicillin). The
photocatalysis results exhibit Ag-ZnO nanostructures have higher degradation than
pristine ZnO nanorods where Ag-ZnO catalysts degrade 92 % of 5 ppm paracetamol
than ZnO (47% degradation) under visible light irradiation. For 10 ppm amoxicillin,
around 67% of degradation using Ag-ZnO catalysts and about 46 using ZnO catalysts.
