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Congratulations to Chang Liu and Yun-peng An for their recent publication on J. Membr. Sci.
An emerging challenge occurs for recovering ionic liquids (ILs) because of their exponential growth in academic and industrial applications. We report for the first time to reclaim water-soluble ILs from their aqueous solutions by osmotically driving water to spontaneously permeate through semi-permeable membranes. Theoretical simulation indicates a weak hydrability of ILs and a tendency to form micelles in water. We thus demonstrate a significant difference in osmotic pressures between the aqueous solutions of ILs and inorganic salts. Four categories of broadly representative ILs are continuously recovered from their diluent aqueous solutions (~1 wt%) with semi-permeable membranes. Our strategy shows an unprecedented performance to reclaim ILs with a record-high ultimate concentration up to 58~78 wt%. It integrates superiorities of low energy consumption, universal applicability toward ILs, versatility for semi-permeable membranes, almost unattenuated water flux, and high rejection to ions. This approach provides new insights into the authentic “green” industrial applications of ILs.
