Hierarchical Porous PLLA@TiO2 Fibrous Membrane for Enhanced and Stable Photocatalytic Degradation Efficiency

Hierarchical porous poly(l-lactic acid) PLLA@TiO2 fibrous membranes have been successfully fabricated by a facile electrospinning/post-treatment method. The unique blossoming porous structure created by inducing the crystallization of PLLA chains in acetone post-treatment increases the specific surface area and exposes the TiO2 nanoparticles (NPs) on the fiber surface. The porous PLLA@TiO2-0.1 membrane using a PLLA:TiO2 weight ratio of 1:5 achieves the highest photocatalytic efficiency. Methylene blue (MB) is used to observe the removal of contaminants and evidence stable removal kinetics over five cycles under the same conditions. Intriguingly, there is a sine functional relationship between the hydrophobic PLLA@TiO2 membranes measured by the water contact angle (WCA) and the removal kinetic constants k fitted by the experimental data on photocatalytic degradation, which can be used to investigate the mechanism between hydrophobicity and photocatalytic degradation of the membranes. Due to their excellent photocatalytic degradation efficiency, recycling, and stability, porous PLLA@TiO2 fibrous membranes have promising application prospects in photocatalytic water treatment.