Antibacterial electrospun chitosan-PEO/TEMPO-oxidized cellulose composite for water filtration

Bacterial contamination of drinking water is becoming a major issue for increasing populations around the world. Current water treatment technologies based on chlorination are effective but generate toxic disinfection by-products. In this study, antibacterial electrospun chitosan-PEO/TEMPO-oxidized cellulose composite was tested for the first time for the deactivation of Gram-positive Bacillus subtilis and Gram-negative Escherichia coli bacteria and their removal by filtration from aqueous solution. Results of the disk diffusion method, confocal microscopy and scanning electron microscopy show that both bactericidal and bacteriostatic behavior against both bacteria depend on the content and mobility of protonated amino groups. It was also found that these properties are enhanced when the biocomposite is doped with copper ions. Filtration tests in a dead-end stainless-steel cell show that both bacteria are completely removed from aqueous solutions (> 95% during the first filtration and 100% after subsequent filtrations). Finally, the composites tested can be used up to three times without significant loss of permeability. However, it was CS-PEO/TOC Cu2+ bio-based composite which displayed the slightest reduction in permeability (2.20%) after three filtrations.