Highly Permeable and Fouling-Resistant Polyamide Nanofiltration Membranes with Embedded Boron Nitride Nanosheets for the Purification of Water

Permeance and fouling are crucial factors restricting the development and application of polymeric nanofiltration (NF) membranes. Introducing nanomaterials into the polyamide (PA) layer is believed to be capable of effectively enhancing the permeance and fouling resistance. In this work, we fabricated a high-permeance thin-film nanocomposite (TFN) NF membrane with preeminent fouling resistance using in situ interfacial polymerization (IP). During this process, different amounts of boron nitride nanosheets (BNNS) were incorporated into piperazine (PIP) aqueous solution to react with trimesoyl chloride (TMC). Due to the reduced diffusion rate of PIP, the obtained TFN-3 membrane presents a PA layer of diminished thickness (∼39.53 nm) and wrinkled structure, which is beneficial for improving the permeance of the NF membranes. As a result, The TFN-3 membrane exhibits a superior pure water flux of 96.28 L m–2 h–1 while maintaining high Na2SO4 rejection. Especially, the TFN-3 membrane possesses fantastic fouling resistance and long-term stability as well. This work provides an efficient approach to constructing high-performance NF membranes for water purification.