Fabrication of high performance TFN membrane incorporated with graphene oxide via support-free interfacial...

A high-performance thin film nanocomposite (TFN) membrane containing graphene oxide (GO) nanosheets was constructed using a support-free interfacial polymerization (SFIP) technique. In this study, an ultrathin composited polyamide (PA) nanofilm was synthesized at the free piperazine (PIP)-GO suspension/trimesoyl chloride (TMC) interface, followed by transfer onto a polysulfone (PSf) UF substrate. The impact of GO loading (0, 0.1, 0.5, or 1 mg/mL) on the physiochemical properties, surface morphology, and hydrophilicity of the composited PA layer and membrane separation performance was investigated. It was found that the GO-modified TFN membranes showed ultra-high hydrophilicity due to the increase in the number of carboxyl and hydroxyl groups in the PA layer. We propose that GO nanosheets play a key role in improving membrane permeability because a strong hydration layer is formed between the water molecules and GO (embedded in the PA layer), acting as a protective film and minimizing the chance of foulants contacting the membrane surface. Compared with TFC, TFN-GO-0.5 simultaneously exhibited a higher water permeability of up to 12.8 L·m^-2·h^-1·bar^-1 (58.1% higher than the TFC membrane) and a higher Na₂SO₄ rejection of approximately 98.4%. Moreover, the introduction of GO nanosheets into TFN membrane resulted in an improved antifouling performance. This facile SFIP method reveals the potential of GO nanosheets for the development of high performance TFN membranes.