Development of Hierarchical Electrospun TiO2-based Photocatalytic Membranes and Evaluation of Technical Properties

Abstract

Nano titanium dioxide nanoparticles (TiO2 NPs), as a core representative in the field of photocatalysis, play a key role in photocatalysis, antibacterial, and UV protection. However, factors such as easy agglomeration of nanoparticles, difficulty in recycling, and low photocatalytic efficiency also limit the performance of TiO2 in practical applications. Poly(L-lactic acid) (PLLA), a non-toxic biodegradable polymer, was used to load TiO2 NPs to overcome the defects of TiO2 NPs in technical applications. The subsequent preparation process was determined by comparing the preparation method (sol-gel coating or electrospinning) and the raw materials (TiO2 NPs or Ti precursor). In this project, PLLA@TiO2 fibrous membranes were developed by electrospinning/posttreatment methods. PLLA@TiO2 membranes were first electrospun, collected as fibrous membranes, and then treated with acetone. The solid fibres are transformed into porous fibres due to the induced crystallisation of PLLA chains in acetone solvent. Consequently, numerous TiO2 nanoparticles (NPs) were exposed on the surface of PLLA fibres to play their role in photocatalytic applications. In addition, in order to investigate the UV protection properties of porous PLLA@TiO2 membrane, a preliminary work on TiO2/keratin finishing cotton fabric for UV protection was designed to investigate the effect of TiO2/keratin on the UV protection and washing resistance of the cotton fabric and to provide a feasible basis for the subsequent porous PLLA@TiO2 membrane/keratin finishing cotton fabric. For technical properties of porous PLLA@TiO2 membrane, the porous PLLA@TiO2 membrane achieved a photocatalytic efficiency of 95.9% for methylene blue (MB) removal compared with previous studies. Furthermore, the MB removal remained good after several repetitions under the same conditions, indicating excellent photocatalytic stability and activity of porous PLLA@TiO2 membrane. In addition, the porous PLLA@TiO2 membrane has a high antibacterial effect, with a photocatalytic antibacterial rate of 99.99%. The enhanced photocatalytic performance was ascribed to the appropriate ratio of PLLA@TiO2 which was determined the distribution of TiO2 NPs on PLLA fibre and the unique blossoming porous structure on fibre surface. Therefore, porous PLLA/TiO2 fibrous membranes have potential application prospect in photocatalytic degradation, photocatalytic antibacterial, and UV protection due to their great free-standing property, photocatalytic degradation efficiency and stability, providing a new idea for the preparation of other new catalysts with poor recyclability

Date of Award	31 Dec 2022
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Hugh Gong (Supervisor) & Jiashen Li (Supervisor)