Development of nanosilver and multi-walled carbon nanotubes thin-film nanocomposite membrane for enhanced water treatment

A new type of thin-film nanocomposite (n-TFN) membrane was synthesized by the interfacial polymerization of a support layer containing acid modified multi-walled carbon nanotubes (MWNTs) and a thin-film layer containing nanosilver (nAg) particles. Microscopic characterization confirmed that MWNTs and nAg particles were distributed in the support layer and the thin-film layer, respectively. Spectroscopic characterization revealed the surface functionalities of the MWNT support layer, and nAg crystallinity and bonding components of the thin-film layer. MWNTs at 5.0 wt.% in the support layer and nAg particles at 10 wt.% in the thin-film layer enhanced the pure water permeability of the n-TFN membrane by 23% and 20%, respectively, compared to 0 wt.% of these components in their respective layers. Increases in pure water permeability and hydrophilicity of the n-TFN membrane were attributed to the diffusive effect of nanopores in the MWNTs. Salt (NaCl, Na2SO4) rejections of the n-TFN membrane were similar to thin-film composite membranes without nAg particles. Pseudomonas aeruginosa PAO1 batch tests indicated greater anti-adhesive and antibacterial properties of the n-TFN membrane compared to similar membranes without nAg particles. This study demonstrated that the acid modified MWNTs and nAg particles enhance the permeability and anti-biofouling properties of thin-film nanocomposite membranes.