(695d) Interfacial Polymerization for Sugar / Ionic Liquid Separations

Ionic Liquids (IL) are tunable green solvents for a variety of chemical and biochemical processes. However, the economic viability of utilizing these green solvents depends on developing processes for their recycle and reuse. ILs are outstanding solvents for biomass fractionation and sugar conversion processes. However, separating saccharides from ILs is generally very difficult due to the similarity of their molecular weight. Here a selective skin layer containing 3-aminophenylboronic acid has been successfully synthesized via interfacial polymerization on the surface of asymmetric polyethersulfone (PES) membranes. The fabricated composite membranes show superior ionic liquid/sugar selectivity at competitive permeability. Moreover, the selectivity can be tuned by varying the monomer composition, the polymerization time and post treatment conditions. While [EMIM]Cl and [BMIM]Cl are able to selectively permeate through the membranes, over 90% of mono- and oligosaccharides are rejected. The compositional, chemical and morphological properties of these nanofiltration membranes are characterized and correlated with their separation characteristics.