Preparation and characterization of thin-film nanocomposite membranes embedded with poly(methyl methacrylate) hydrophobic modified multiwalled carbon nanotubes by interfacial polymerization

Carbon nanotube enhanced thin-film nanocomposite membranes were prepared by incorporating carbon nanotubes (CNTs) into the active layers of membranes used for water treatment. For inclusion into these active layers, a grafting procedure for carbon nanotubes was set up to increase their hydrophobicity. Multiwalled carbon nanotubes (MWNTs) grafted by poly(methyl methacrylate) (PMMA) were synthesized via a microemulsion polymerization of methyl methacrylate (MMA) in the presence of acid-modified multiwalled carbon nanotubes (c-MWNTs). Subsequently, polyamide thin-film nanocomposite (TFN) membranes containing PMMA–MWNTs were prepared via interfacial polymerization. Morphology studies demonstrate that MWNTs have been successfully embedded into the active polyamide layer. The rejection of Na2SO4 was high (99%), and the water flux was about 62% increased compared to the thin-film composite membrane when using 2 g/L piperazine (PIP) in the aqueous phase, 4 g/L trimesoyl chloride (TMC) and 0.67 g/L PMMA–MWNTs in the organic phase, which demonstrates that PMMA–MWNTs significantly improve selectivity and permeability.