Lightless catalytic layered chitosan coating film using doped TiO2@metal ions nanoparticles for highly efficient dye degradation in aqueous media and disinfection applications

Chitosan-based materials are widely used in various industries due to their environmental friendliness (biodegradable and non-toxicity) and other antimicrobial properties. Improving the chitosan capacities using additional components such as titanium dioxide (TiO 2 ) and other nanoparticles proves beneficial. Here, we propose the combination of chitosan-TiO 2 nanocomposites (ChiTiO) with various metal ions (silver, zinc, copper, and iron), forming novel chitosan-based films to improve the capacities of the material further. The ChiTiO-ion metals nanocomposites and films were synthesized and characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), ultraviolet-visible spectroscopy (UV–Vis), Fourier transforms infrared spectroscopy (FT-IR), X-ray fluorescence (XRF), and cyclic voltammetry techniques. The biological activities of the metal-doped formulations showed increased antioxidant activities led by ChiTiO@Ag. Additionally, the methylene blue (MB) dye degradation capabilities were dominated by ChiTiO@Cu. The material showed a higher specificity towards MB than other dyes (methyl orange and bromophenol blue). The photocatalytic degradation at high temperatures (60 °C) was faster than at ambient (25 °C) and cold (4 °C) temperatures. The reusability of the film showed sustained photocatalytic capacities even after three cycles with a low loss of 16.7%. The antimicrobial activities of the films were tested against three pathogens ( S. aureus , C. albicans , and P. aeruginosa ) under different light conditions. Data showed ChiTiO@Ag with a concentration of 0.5 g composite having the best activity compared with the other materials. The most important finding is the ability of the proposed films to perform their activities without the need for any light activation. Lastly, ChiTiO@ion metals provide promising applications as ambient light packaging materials, coating materials, and photocatalysts.