Recent progress in advanced polyamide nanofiltration membranes via interfacial polymerization for desalination and beyond

The synthesis of polyamide (PA) nanofiltration (NF) membranes by interfacial polymerization (IP) for ion and molecular separations has been studied for decades, but the pursuit of higher separation efficiency and expanded usage scenarios motivates the continuous progress in PA NF membrane research. Great efforts to break the trade-off relationship between membrane permeability and selectivity of PA-NF membranes by fine-tuning the IP technique have been reported in recent years. The contemporary advances in designing PA membrane structure, such as crumpling morphological structures, tailored crosslinked networks, ultra-low membrane thickness and the extra permselective channels are evaluated and their corresponding structure-performance interplay are discussed. Specific conditions of the IP process, such as monomer concentration, solvents, additives, support layers, phase interface states and fabrication skills, as well as their influence on membrane permeability, ion or molecule selectivity are summarized and examined based on the performance in various applications. This critical review on the state-of-the-art PA NF membranes can provide significant insights into the fabrication of next generation high-performance membranes for desalination and other diverse extended advanced applications.