Electrospun Nanofiber Membranes for Water Treatment and Reuse

Water treatment and reuse is becoming an increasingly important issue for all regions of the world regardless of their level of water abundance or aridity. Membrane technology has provided a versatile platform for developing a host of water treatment technologies that enable us to tap sources for water that only decades ago would have never been considered as viable sources of water (seawater, produced water, wastewater).  Continued innovation in the water treatment membrane field continues today as new materials are sought that leverage important structure-property relationships that push the barrier of membrane performance. One material in particular, nanofiber nonwovens, has recently achieved attention as a possible platform for improving membrane performance because of their intrinsically high permeability, low resistance to mass transfer, and high surface area.  In our work, we explore the use of polymer nanofiber nonwovens made through electrospinning for use across a wide range of membrane applications.  These include:

• Electrospun supported thin film composite membranes for forward osmosis (FO):  Electrospun materials are demonstrated to have excellent mass transfer properties which reduce resistances to solute transfer in forward osmosis.  
• Nanofiber membranes for membrane distillation (MD): Electrospun nonwovens have properties of high porosity and small pore size, making them suitable for MD applications. We demonstrate high flux performance of these membranes under very modest temperature gradients using high salinity feeds.  
• High surface area activated carbons: Using electrospun precursors, we have established protocols for making high surface area carbon materials in a nonwoven configuration that are appropriate for organic removal in sorption applications.  
• Use of commercial nanofiber materials for membrane applications: We have explored the use of commercial nanofiber nonwovens from DuPont in both FO and MD applications.  This demonstrates that commercial nanofiber nonwovens, which are made roll-to-roll, are applicable to these emergent membrane disciplines.  Availability of these materials commercially could aid in commercialization efforts.  

In all, this work demonstrates the promise of using nanofibers across a number of key membrane disciplines in the water treatment space.