Fabrication of novel thin-film nanocomposite polyamide membrane by the interlayer approach: A review

Thin-film nanocomposite (TFN) membrane based on polyamide (PA) chemistry was widely applied for water purification and desalination process due to the improved water permeance. It remains a great challenge to significantly enhance rejection because of the non-selective defects caused by the aggregation of nanomaterials in the PA layer. Novel interlayer-based TFN (iTFN) membrane containing nanomaterial interlayer between the porous substrate and PA layer is the promising candidate to improve PA integrity and thus overcome the ubiquitous trade-off between permeability and selectivity. The nanomaterial interlayer not only promotes the subsequent interfacial polymerization (IP) but also provides improved pathways for water transport, which leads to simultaneous improvement in membrane permeability and selectivity. This review systematically categorizes nanomaterial interlayers into three types according to construction methods, namely, direct deposition, in situ growth and functional group-anchored in situ assembly (FAISA). The mechanism of interlayer modulating IP process and PA structure, as well as the effects on water transport, are comprehensively analyzed. Encouraging results reveal that using MOFs interlayer prepared by FAISA is the most promising way to break the trade-off in manufacturing reverse osmosis membranes. Finally, challenges and future efforts are presented for advancing iTFN membranes.

Automated summary

Thin-film nanocomposite (TFN) membranes based on polyamide (PA) chemistry are widely used for water purification and desalination due to improved water permeance. However, the aggregation of nanomaterials in the PA layer leads to non-selective defects and limits rejection efficiency. A promising solution is the use of interlayer-based TFN (iTFN) membranes, which contain a nanomaterial interlayer between the porous substrate and PA layer to enhance PA integrity and overcome the trade-off between permeability and selectivity. This review categorizes nanomaterial interlayers into three types and analyzes their effects on interfacial polymerization and water transport. Encouraging results demonstrate that using MOFs interlayer prepared by FAISA method is the most promising way to improve reverse osmosis membrane manufacturing.