Efficient photodegradation of paracetamol by integrated PES-ZnO photocatalyst sheets

Abstract

In this study, PES-ZnO (Polyethersulphone-Zinc Oxide PZ) photocatalyst sheets were prepared via the phase inversion method and used in the oxidative degradation of paracetamol, a commonly detected pharmaceutical in water matrices. The incorporation of ZnO in the polymer matrix, confirmed by X-ray Diffraction (XRD), Scanning Electron Microscope/Energy Dispersive X-ray (SEM-EDX), and X-ray Photoelectron Spectroscopy (XPS) analyses, led to formation of porous structure with tear-like pores that subsequently increased the porosity of the polymer matrix PZ sheet. The PZ sheet containing 15 wt% of ZnO, PZ-15, exhibited 92 % degradation efficiency at a slightly alkaline condition when using four pieces of the PZ-15 sheet. The degradation rate constant of 4.8 × 10-3 min−1, based on pseudo-first-order kinetics, was obtained with hydroxyl radicals identified as the main species responsible for the degradation of paracetamol. The degradation process proceeded via hydroxyl radical attack of the C[dbnd]C at the para position of the compound that yields hydroquinone as a by-product. The reusability study demonstrated the feasibility and reliability of using the PZ-15 photocatalyst sheet for up to six cycles with comparable performance in the degradation of paracetamol in an aqueous solution.