In situ assembly of graphitic carbon nitride/polypyrrole in a thin-film nanocomposite membrane with highly enhanced permeability and durability

Although thin-film nanocomposite (TFN) membranes have been proposed as a competitive approach for improved reverse osmosis performance within the last decade, their intrinsically poor organic-inorganic interfacial compatibility and low durability still hinder further upscaling. In this study, a new in situ assembly strategy is proposed to solve this dilemma by using polypyrrole (PPy) to build a bridge between polyamide matrix and nanomaterial (graphitic carbon nitride, g-C 3 N 4 ) and further fabricate g-C 3 N 4 /PPy-incorporated TFN membrane. The synthesized g-C 3 N 4 /PPy nanocomposites are hybridized into the interfacial polymerization process, which endows the TFN membrane with a smaller “ridge-valley”, higher hydrophilic and thinner polyamide layer. With 0.005 wt% of g-C 3 N 4 /PPy, the water permeability of TFN membrane is increased to 377 % (4.0 L·m −2 ·h −1 ·bar −1 ), while keeping a similar NaCl rejection (99.1 %) to pure polyamide membrane. Importantly, the resulting TFN membrane exhibits high chlorine resistance in acidic, neutral and alkaline environments . Moreover, the TFN membrane has superior antifouling performance for organic, inorganic and mixed organic-inorganic foulants, which is of vital importance for the long service life of TFN membranes. This study offers a facile avenue to solve the application needs of advanced TFN membranes for efficient desalination with stable high-quality water.