Nanophotonics Enhanced Direct Solar Membrane Distillation: Towards Off-Grid Desalination and Water Purification
Nonconventional water sources, including seawater, brackish water and wastewater, have become an important, and in some regions, necessary form of water supply to sustain economic growth and societal development. At the center of the various strategies utilizing these alternative water sources is desalination. Critical limitations of existing desalination technologies are the high energy consumption and concentrate management. Much research effort has been devoted to the development of high permeability membrane materials to lower the energy demand of desalination. However, with the energy use of reverse osmosis systems approaching the thermodynamic limit, research on factors other than membrane permeability is necessary to address these limitations. Technologies that can utilize renewable energy and minimize concentrate volume are particularly attractive. Photothermal nanomaterials can absorb a broad spectrum of light and convert the photon energy to heat locally. The Nanosystems Engineering Research Center for Nanotechnology Enabled Water Treatment (NEWT) has developed a novel nanophotonics enhanced direct solar membrane distillation (NESMD) technology that exploits the photothermal activity of nanomaterials to provide localized heating to drive the membrane distillation (MD) process and improve the MD thermal efficiency. The presentation will discuss the fundamental science, materials development, reactor and process modeling and design, as well as performance evaluation of the NESMD system.