Chitosan and TiO2–C,N nanocomposite membranes: Synthesis, characterization, and evaluation of antibacterial efficacy

Abstract

Nowadays, advanced oxidation processes are one of the best techniques for the removal of organic matter from an aqueous medium, and they are also used as a disinfection process. TiO2 has been used for many pathogenic microorganisms due to its catalytic properties applied in water disinfection processes; however, its recover and reuse is difficult since it is a powder. In this context, diverse materials and methods have been tested to support TiO2. The objective of the present study is to synthesize an economic and environmentally friendly material, with the properties of being efficient in eliminating pathogenic microorganisms such as Escherichia coli (E. coli) and being easy to eliminate from aqueous solutions. Photocatalytic membranes of chitosan and titanium dioxide doped with carbon and nitrogen (Ch/TiO2–C,N) were obtained. To determine the morphology, structure, composition, and optical properties of theTiO2-C,N powder, it was characterized by FE-SEM, XRD, DRUV-Vis, and XPS, and the membranes were characterized by FE-SEM and FT-IR. The antibacterial activity of the membranes was evaluated using Escherichia coli as a model organism under visible light. The Colony Forming Unit (CFU) was calculated for each sample. Chitosan membranes were successfully synthesized with TIO2-C,N and proved to be efficient in the E. coli elimination. It was observed that 93.77 % of the bacterial inactivation after 2 h with the Ch/TiO2–C,N membranes, and a total inactivation after 3 h under visible light. The advantage of this material is that it's efficient and easily recoverable from the aqueous medium. It could also be used as an alternative method to chlorine or as a complementary method in water treatment.