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−2h−1bar−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 high-performance RO membrane.