Fe,N co-doped TiO2 photocatalyst supported in PLA nanofibers for sunlight-driven degradation of water organic pollutants and Escherichia coli Inactivation

Abstract

Water contamination by organic pollutants and pathogens poses serious environmental and public health risks. Developing sustainable, efficient materials that can simultaneously degrade organic pollutants and inactivate bacteria in water offer a low cost, eco-friendly alternative to conventional treatment methods that often require high energy or produce toxic by-products. For this purpose, doped TiO₂ photocatalysts are been studying, but still there are limitations in terms of optimal concentration, synthesis, supporting substrates and modest band gap reduction. In this work, metal and non-metal co-doped TiO₂ photocatalysts (Fe, N, and Fe-N) are immobilized in polylactic acid (PLA) submicrometric fibers mats prepared by solution blow spinning (SBS). These composites are evaluated for their dual function: the photocatalytic degradation of organic pollutants under simulated sunlight and the inactivation of Escherichia coli. The morphological study of the materials by scanning electron microscopy points out the uniform dispersion of photocatalysts in the PLA fibers with dimensions at the submicrometric scale and rough surfaces where photocatalytic particles are located. Raman spectroscopy confirms the stability of the active anatase phase of the photocatalysts after their immobilization. As a consequence of a higher bandgap energy reduction of TiO₂ and a better separation of photo-generated charge carriers, the PLA/Fe-N-TiO₂ system demonstrates superior photocatalytic activity compared to the single-doped systems, showing in addition consistent performance over five reuse cycles, with degradation efficiencies exceeding 55 %. Additionally, it achieves over 90 % E. coli inactivation after 180 min. These results highlight the potential of PLA/Fe-N-TiO₂ supported in PLA nanofibers as a sustainable, reusable solution for water treatment, effectively degrading organic pollutants and inactivating harmful bacteria.