Reverse osmosis (RO) membranes have been a key material for the membrane-based separation process including seawater desalination and water treatment. Many attempts have been made to improve the permselectivity of RO membranes, which thus increase the energy and cost efficiencies of the desalination and water treatment processes. Among many proposed strategies, the post-treatment on the membrane with an organic solvent, so-called solvent activation, has been regarded as one of the effective methods to enhance RO membrane performance. However, solvent activation with the previously used organic solvents resulted in a typical flux-rejection trade-off limitation (enhanced water flux along with decreased salt rejection). Furthermore, there have not been proposed clear mechanisms and reliable criteria of the solvent activation effects. In this study, we demonstrate that a new class of an organic solvent, benzyl alcohol, can effectively activate the RO membrane, which significantly enhance water flux without deteriorating salt rejection, thereby overcoming the critical performance trade-off constraint. The underlying activation mechanism was elucidated by comprehensively characterizing the physicochemical structures, properties and separation performance of the membranes activated with various organic solvents. Importantly, based on the results, we proposed a reliable indicator of the solvent activation effect.

Overcoming the permeability-rejection trade-off of RO membranes via activation with a novel organic solvent

2019 Spring National Meeting

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