Graphitic carbon nitride (g-C3N4) nanosheet augmented polyamide composite membranes for enhanced pervaporation desalination

Desalination of high-salinity water remains a critical challenge for sustainable water management, as conventional membrane processes are inherently constrained by osmotic pressure limitations. In this study, graphitic carbon nitride (g-C 3 N 4 ) nanosheets were incorporated into a polyamide (PA) selective layer via interfacial polymerization on a polyethersulfone (PES) ultrafiltration membrane for pervaporation (PV) desalination. Comprehensive characterization revealed that g-C 3 N 4 incorporation increased surface hydrophilicity and modified the morphology and surface chemistry of the PA-selective layer. The optimized PA/g-C 3 N 4 0.05@PES membrane exhibited an exceptional water flux of 74.83 kg m −2 h −1 with a salt rejection exceeding 99.9% using a 3.5 wt% NaCl feed at 70°C. Notably, the membrane demonstrated exceptional robustness under hypersaline conditions, sustaining a flux of 27 kg m −2 h −1 and near-complete rejection even at 10 wt% NaCl, a domain where conventional pressure-driven processes face severe osmotic limitations. Furthermore, the membrane exhibited improved resistance to fouling, with minimal performance degradation after exposure to humic acid foulant and stable long-term operation. Compared to conventional PA membranes and previously reported g-C 3 N 4 -based systems, the developed membrane demonstrates superior performance. This work highlights the potential of integrating g-C 3 N 4 into PA matrices and demonstrates that PV is a highly promising strategy for efficient desalination of high-salinity water.