Kinetic modelling and proposed mechanistic pathway for photocatalytic degradation of 4-aminopyridine using cuprous oxide nanoparticles

摘要

Cuprous oxide nanoparticles (Cu2O NPs) were synthesized using Tabernaemontana divaricate leaves extract, a reducing and stabilizing agent. Prepared Cu2O NPs were characterized by FT-IR, XPS, XRD and EDX. FT-IR analysis of Cu2O NPs showed a sharp peak at 610 cm(-1) attributed to the vibration mode of Cu (I)-O. XPS spectra of Cu2O NPs exhibited peaks at 932.5 eV and 952.6 eV which indicated the presence of Cu 2p(3/2) and Cu 2p(1/2) and confirmed the formation of Cu2O NPs. Synthesized Cu2O NPs have a cubical and hexagonal shape with an average size length of 85 nm. EDX studies confirmed the high purity of Cu2O NPs with 81.72% copper, 11.05% oxygen and 6.05% carbon. The photocatalytic degradation of 4-aminopyridine onto Cu2O NPs in visible light showed 80% degradation efficiency, 82% chemical oxygen demand removal and 65% total organic carbon (TOC) removal after 235 min of reaction time at pH 3. Lumped kinetic model (LK) for TOC removal of 4-aminopyridine using Cu2O NPs showed a high value of regression coefficient (R-2 = 0.99) which emphasized that the experimental data are best fitted to the model. Ten intermediate fragments were detected in LC-MS spectra based on mass-to-charge ratio (m/z) after 235 min of reaction time.