Preparation of advanced reverse osmosis membrane by a wettability-transformable interlayer combining with N-acyl imidazole chemistry

Highly permeable thin-film composite (TFC) reverse osmosis (RO) membranes are desirable for desalination and water reuse. Various interlayers have been developed to improve water permeance of TFC nanofiltration (NF) membranes, however the traditional interlayer strategy trends not to work well for RO membranes. Herein, a novel interlayer with transformable wettability, and with function of releasing placeholder agent is designed for the fabrication of high-permeance RO membrane. The initial interlayer provides an instable hydrophobic surface for interfacial polymerization (IP) to facilitate the formation of a rough separation layer containing interior nanovoids, and then it translates into a hydrophilic gutter layer through simple water immersion to further enhance the overall transport efficiency of the TFC membrane. In addition, the interlayer can in-situ release imidazole component to participate in the IP reaction, which is proven to influence the intrinsic properties of the membrane materials due to the unique acyl-transfer property of N-acyl imidazole. As a result, the water permeance of the as-fabricated RO membrane is up to 5.87 L m(-2)h(-1)bar(-1), nearly 6-fold enhancement compared to the control group, while still maintaining comparable rejection toward NaCl, thus successfully overcoming the permeability-selectivity trade-off limit. This work paves a new way for preparing highperformance RO membrane.

Automated summary

In this study, a novel interlayer with transformable wettability and the ability to release placeholder agents was designed for the fabrication of highly permeable RO membranes. The interlayer provided an unstable hydrophobic surface for interfacial polymerization, facilitating the formation of a rough separation layer with interior nanovoids. It could then transform into a hydrophilic gutter layer through simple water immersion, further enhancing the overall transport efficiency of the membrane. Additionally, the interlayer could release specific components in-situ to participate in the reaction, influencing the properties of the membrane materials.