(660a) Hydrophilization of Thin Film Composite Membrane Support Layers for Engineered Osmosis Applications

Today's thin film composite membranes have a highly anisotropic structure which provides both high permeability and selectivity in pressure-driven membrane separations like reverse osmosis and nanofiltration. This asymmetric structure, however, is detrimental to engineered osmosis applications, including forward osmosis and pressure retarded osmosis, due to the presence of concentration polarization. The support layers of these membranes are also very hydrophobic. This intrinsic hydrophobicity prevents wetting of the support layers and results in reduced mass transport and enhanced concentration polarization. This investigation considers surface modification with various techniques intended to hydrophilize the support layer of commercial reverse osmosis membranes without causing degradation of membrane performance (selectivity, permeability). These efforts resulted in an increased water flux (by as much as 10-fold) for various EO applications. These efforts may enable the use of commercial reverse osmosis membranes for engineered osmosis.