(18e) Nanophotonic Materials for Low Cost Solar Desalination

A novel solar-thermal desalination technology using photothermal membrane, including carbon-based nanomaterials, has been developed and tested at NEWT (NSF E.R.C) for low cost desalination. The photothermal membrane is serving as a solar-thermal collection and a desalination membrane in a single reactor. The porous coating layer on the base membrane contains photonic nanoparticles that strongly absorb sunlight across a wide range the solar spectrum (UV to near IR), and convert the photon energy to heat highly locally and efficiently. This results in a high temperature on the feed-membrane interface, a high vapor pressure difference across the membrane, and a high vapor transport rate. Very importantly, the localized heating on the membrane surface results in a much higher thermal efficiency than conventional membrane distillation process that heats the bulk feed water. The technology has been successfully demonstrated, on a large scale, at at 29.7174° N, 95.4018° W to desalinate different sources of water under different intensities of solar irradiance and environmental conditions.