TiO2/Polyethersulphone films for photocatalytic degradation of acetaminophen in aqueous solution

• Published in: Journal of molecular liquids 2021-09, Vol.338, p.116692, Article 116692
• Main Authors: Chijioke-Okere, Maureen O., Adlan Mohd Hir, Zul, Ogukwe, Cynthia E., Njoku, Paschal C., Abdullah, Abdul H., Oguzie, Emeka E.
• Format: Article
• Language: English
• Subjects: Density functional theory; Immobilized catalyst; Pharmaceutical residues; Photocatalysis; Polyethersulphone support
• ISSN: 0167-7322
• DOI: 10.1016/j.molliq.2021.116692

•TiO2/polyethersulphone removal of acetaminophen in aqueous solution.•Degradation efficiency is pH dependent, reaching a plateau at pH 8.•Mechanism involves hydroxylation and cleavage of N-C of carbonyl group.•Radical and electrophilic attack initiated at the carbonyl group. In this study, TiO2-polyethersulfone films with different TiO2 loadings, prepared by the phase inversion method were tested as photocatalysts for degradation of acetaminophen in aqueous solution. The prepared films were characterized by XRD, SEM-EDX, AFM, and XPS. The successful incorporation of the titanium dioxide nanoparticles was confirmed by the XRD and SEM-EDX. SEM images revealed a much smoother surface for the pristine PES as compared to the TiO2-PES films, while EDX result confirmed the immobilization of titanium, as increasing amounts of titania were detected with increased loading of titanium dioxide. The SEM cross sectional images also show that the prepared films transformed into porous structures with tear-like pores and the porosity increased from 0.06%, for pristine PES, to 0.35% for the (14 wt%) TiO2-PES, and then dropped slightly to 0.32% in (17 wt%) TiO2-PES due to the onset of aggregation. The TiO2-PES photocatalyst film with 14 wt% content of TiO2 exhibited 51% degradation efficiency for a film surface area of 80 cm2, and a maximum efficiency of 80% at 320 cm2 film surface area. However, an increased TiO2 loading up to 17 wt% led to a decline in efficiency which is attributed to agglomeration and possible defective pore structure of the films. The reactivity of the acetaminophen molecule, modelled using the density functional theory (DFT), enabled identification of the acetamido group and the aromatic ring as the regions most prone to electrophilic and radical attack, respectively.