Optimizing separation layer structure of polyamide composite membrane for high permselectivity based on post-treatment: A review

Membrane separation technology based on reverse osmosis (RO)/nanofiltration (NF) membrane has emerged as an effective solution to address the current shortage of fresh water resources. Polyamide thin film composite (PA-TFC) membranes are widely adopted in RO/NF systems due to their superior permselectivity, chemical and mechanical stability. Further enhancing the performance of PA-TFC membrane can improve production water quality and reduce energy consumption, which has been a key focus in membrane research. This paper reviewed recent literature on improving the permselectivity, as well as anti-fouling, anti-bacterial, anti‑chlorine, and stability of PA-TFC membranes via post-treatment processes, an essential step in their preparation, and focused on three aspects: heat curing, separation layer activation, and surface modification. The mechanism and the advantages/disadvantages of the post-treatment methods on improving membrane structure and performance were discussed. Additionally, the relevance and combining process of these methods were analyzed, and the possible reasons underlying the contradictory conclusions in the independent studies were discussed. Finally, the potential for developing high-performance PA-TFC membranes using post-treatment was summarized and projected.