Multilayer assembly of thin-film nanocomposite membranes with enhanced NaCl and antibiotic rejection

Reverse osmosis and nanofiltration by thin-film nanocomposite (TFN) membranes are energy-efficient processes for water purification. However, it is difficult to fabricate high-performance TFN membranes in controllable manner. In this work, the uniform and multilayered polyamide (PA)-graphene oxide (GO) TFN membranes were assembled by a simple and controllable strategy, named as multilayer deposition, which was performed by consecutively spin-coating GO, meta-phenylene diamine (MPD)/piperazine (PIP), and trimesoyl chloride (TMC) solutions on the substrates. The introduction of GO could reduce defects, resulting in formation of smooth and defect-free reverse osmosis/nanofiltration membranes with significantly increased NaCl and antibiotic rejection. For example, the TFN reverse osmosis membrane showed NaCl rejection of 99.1% and water permeance of 1.83 L m−2 h−1 bar−1, accompanied by substantially enhanced antifouling property.