RO membrane fabricated via a facile modified heat-treating strategy for high-flux desalination

In this study, we utilized the NaOH solution as a heat-treating medium to replace the conventional oven-heating process after interfacial polymerization for the RO membrane fabrication. XPS result confirmed that the nascent RO membrane possessed a gradient cross-linking density along the polyamide layer depth, which is relatively loose on top and dense facing the substrate. The top loose polyamide could be exfoliated under NaOH treatment. The TFC membrane treated in a 1.5 mol L-1 NaOH solution exhibited a pure water flux nearly 3 times higher than that heat-treated in a water bath and also maintained a high NaCl rejection. In consideration of the practical operation process, membrane stability was evaluated, and the results showed that the membrane heat-treated by 1.5 mol L-1 NaOH solution possessed good long-term and pH stability. Thus, the facile heat-treating strategy provides a new path for fabricating high flux TFC-RO membranes. •Novel heat-treating medium of NaOH solution was utilized to fabricate the novel RO membrane.•The top loose layer of the nascent polyamide membrane could be exfoliated under NaOH treatment.•The modified heat-treating strategy showed great superiority over traditional oven-heating process.