Carbon based membranes with modified properties: thermal, morphological, mechanical and antimicrobial

Abstract

Conjugation of biodegradable cellulose acetate (CA) with high-aspect-ratio carbon nanotubes may increase common properties as well as the specific antibacterial activity of the resulting nanocomposite. Hence, we developed nanocomposite membranes based on pristine-multiwalled carbon nanotubes (p-MWCNTs) and CA. Two air gaps (100 and 200 μm) of a film coating applicator were used for casting the solutions into glass plates, and the membrane precipitation was attained via nonsolvent induced phase separation. The thermal (TGA and DSC), morphological (SEM), and dynamical properties (DMA) of the nanocomposite membranes improved with the increasing content of p-MWCNTs in the nanocomposites. In addition, after 48 h contact there was a reduction of more than 70% and 80% of Staphylococcus aureus and Escherichia coli bacteria, respectively, due to the electrostatic repulsion between the negatively-charged CNTs-loaded nanochannels and the bacterial colonies, as explained by zero charge point measurements. Antibacterial testing confirmed the already discussed antifouling properties of the nanocomposite membranes compared to pristine CA membranes. Membrane performance analysis revealed a rejection of over 24% of E. coli, thus establishing the potential of these nanocomposites for applications in wastewater filtration and biofilm removal.