Generating a technology platform for water harvesting from humid air using carbon nanotube-based nanocomposites

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This project involves the development of an innovative strategy for water generation based on the recovery ofatmospheric humidity in the gas phase. It tries to avoid the current hindrances in fog harvesting technologiesbased on the recovery of water micro droplets from fog and clouds, i.e. from very humid air. Achieving a lowcost method able to collect water from ambient air even at low relative humidity (RH), down to around 20%RHin arid regions, would strongly impact many regions of the world particularly in the present climate changeevolution. The proposed idea consists in forcing the water vapor in the air to nucleate heterogeneously intowater droplets on super-hydrophillic surfaces having strongly enhanced surface area, and extracting the waterdroplets using various strategies based on hydrophobicity and porous media. Water generation from humid aircorresponds to typical dehumidification devices. The challenge is however to generate a surface on which theheterogeneous nucleation, i.e. the gas-to-liquid micro-droplet generation, is made to occur under a very smallcooling temperature below the ambient temperature. In other words, a dehumidifier requiring a minimal energyinput. Such conditions were shown by the Plasma Processing Laboratory at McGill University to occur onforests of carbon nanotubes functionalized to full hydrophillicity. Water was shown to be captured, while zonesfunctionalized to be hydrophobic were shown to enable the extraction of water droplets. This collaborationproject focusses on evaluating three potential avenues for the design of water-collecting structures, all threebased on the approach developed by PPL for functionalized forests of carbon nanotubes.