Nanophotonics-enabled Solar Membrane Distillation for Off-grid Water Purification
Dongare, Pratiksha D.
Halas, Naomi J
Master of Science
With more than a billion people lacking accessible drinking water, there is a critical need to convert non-potable sources such as seawater to water suitable for human use. However, energy requirements of desalination plants account for half their operating costs, so alternative, lower-energy approaches are equally critical. Membrane distillation (MD) has shown potential due to its low operating temperature and pressure requirements, but the requirement of heating the input water makes it energy intensive. Here we demonstrate nanophotonics-enabled solar membrane distillation (NESMD), where highly localized photothermal heating induced by solar illumination alone drives the distillation process, entirely eliminating the requirement of heating the input water. Unlike MD, NESMD can be scaled to larger systems and shows increased efficiencies with decreased input flow velocities. Along with its increased efficiency at higher ambient temperatures, these properties all point to NESMD as a promising solution for household- or community- scale desalination.
Desalination; Carbon black; Solar; Nanophotonics; Phothermal