Electrospun nanofiber supported thin film composite membranes for engineered osmosis

Engineered osmosis (EO) is a membrane based separation technology with applications to sustainable energy, resource recovery, and water production. Still emerging, EO utilizes energy stored as chemical potential (osmotic pressure) to generate power or purify water, but the lack of membranes with suitable water flux, solute rejection, mechanical strength, and chemical stability has limited EO development. In this study, we attempt to address low water flux by proposing a novel thin film composite membrane for EO. This TFC membrane comprises an electrospun polymeric nanofiber support layer and a polyamide skin layer formed by in situ polymerization. The best nanofiber supported-polyamide composite membranes exhibited two to five times higher flux with up to 100 times lower salt flux than a standard commercial forward osmosis membrane. These results suggest that electrospun nanofiber supported polyamide composite membranes may enable applications like forward osmosis where internal concentration polarization is the performance-limiting factor. More research is needed to establish the applicability of this new membrane design for engineered osmosis applications involving harsh chemical environments and elevated mechanical pressures.