Permanent electrospun superhydrophobic hybrid nanocomposite fibers for atmospheric fog harvesting
The scarcity of pure drinking water has been one of the major humanitarian challenges in the globe. The world population growth, urbanization, and depleting water resources are deteriorating the water quality and global climate change has also intensified this crisis especially in countries with arid and semi-arid regions. The present study investigated the availability and practical use of nanomaterials and membranes for the collection and production of pure drinking water from various natural sources. The polyacrylonitrile (PAN) and recycled expanded polystyrene (EPS) based nanofibers with the combination of microparticles and nanoparticles to fabricate hierarchical structures where structural features of both the beetle’s back and spider silks were integrated. The fiber's morphology, surface hydrophobicity, crystal structure, and fog harvesting capacity of the nanocomposite fibers were investigated. The experimental tests of these superhydrophobic nanocomposites demonstrated the feasibility of the freshwater production with the daily water productivity of more than 1.49 liter/m2 of nanocomposites. It is estimated that the materials cost of making such nanocomposites to supply minimum daily water consumption for a household with 2 members (i.e., 6 liters) is only $4.96 (USD). The recycled EPS nanocomposite fibers also displayed superhydrophobic characteristics with a water contact angle of 152.3° and the feasibility of the freshwater production with the daily water productivity of more than 1.35 liter/m2. Besides, PAN/ Acrylamide monomer (AM) based hybrid hydrogel is also synthesized and investigated its water vapor harvesting capacity where relative humidity (RH) is typically low and it can be driven by the abundant source of solar-thermal energy with higher efficiency. Also, some important recommendations are made based on our research results and current practices of nanotechnology applications in the water production industry for freshwater production.
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