Polyelectrolyte Multilayers for Forward Osmosis, Combining the Right Multilayer and Draw Solution

Polyelectrolyte multilayers (PEMs) are highly promising materials as selective separation layers on the inside of hollow fiber membranes. We investigate forward osmosis (FO) performance poly(4-styrene sulfonate) (PSS)/poly(allylamine) (PAH)- and PSS/poly(ethylene imine)-based PEM membranes apply different draw solutions. The show properties, demonstrated by their retention behavior under nanofiltration conditions against five relevant solutions (NaCl, MgCl2, MgSO4, Na2SO4, trisodium citrate (TSC)). Subsequently, relation between properties FO was studied for various PSS/PAH showed lowest reverse salt flux MgCl2 while PSS/PEI Na2SO4 TSC. Combining right membrane with solution is thus key to getting low fluxes in FO. Cross-linking PEMs resulted an overall lower water flux; however, selectivity not affected.