In the foggy regions of nations like Peru, Bolivia, Chile, Morocco, and Oman, locals have long relied on the simple yet effective technology of fog nets to capture water droplets for drinking, cooking, and washing. This ingenious method, capable of harvesting hundreds of liters of water daily, is a lifeline in areas where rainfall or spring water is sparse. However, in our increasingly polluted world, the water collected from fog is often contaminated, rendering it unsafe for consumption without proper treatment.
Enter a team of scientists from ETH Zurich who have pioneered a revolutionary technology that simultaneously collects and purifies water from fog. This game-changing approach involves a close-mesh lattice of metal wire coated with a blend of specially chosen polymers and titanium dioxide. The polymers facilitate efficient water droplet collection and quick drainage into collection containers, while the titanium dioxide acts as a catalyst, neutralizing many organic pollutants within the droplets.
A New Dawn in Harvesting and Purifying Water from Fog
Countries like Peru, Bolivia, Chile, Morocco, and Oman, known for their foggy areas, have long been using fog nets to capture water droplets for drinking, cooking, or washing. A fog net with an area of just a few square meters can harvest hundreds of liters of water daily. However, atmospheric pollution has been a significant drawback as harmful pollutants are also caught in the water droplets. Now, scientists from ETH Zurich have devised a revolutionary method to collect and purify water from fog.
Harnessing Titanium Dioxide for Fog Harvesting
Led by Ritwick Ghosh of the Max Planck Institute for Polymer Research, the team of scientists developed a close-mesh lattice of metal wire coated with a mixture of specially selected polymers and titanium dioxide. The polymers aid in efficient collection of water droplets and their quick trickle down into a container, while the titanium dioxide acts as a chemical catalyst. This catalyst breaks down the molecules of many pollutants, rendering them harmless. According to Ghosh, this system is ideal for areas with high atmospheric pollution, such as densely populated urban centers.
Minimal Maintenance, Maximum Efficiency
This innovative technology requires little maintenance and no energy other than a small, regular dose of UV light to regenerate the catalyst. Thanks to its photocatalytic memory, half an hour of sunlight is enough to reactivate the titanium oxide for another 24 hours, proving particularly useful in foggy areas where sunlight is often scarce. The system underwent testing in the lab and a small pilot plant in Zurich, where it collected eight percent of the water in artificially created fog and broke down 94 percent of the added organic compounds.
A Solution for Water Scarcity, Beyond Drinking Water
While this technology offers a solution for harvesting drinking water from fog, it also presents opportunities for water recovery in cooling towers. Senior author Thomas Schutzius, a professor of Mechanical Engineering at the University of California, Berkeley, suggests capturing some of the steam that escapes into the atmosphere from cooling towers to ensure it is pure before returning it to the environment. The team plans to refine these methods further in future research, hoping to make better use of fog and steam as underutilized water sources.
Fog Collection: An Ancient Practice with Modern Implications
Fog collection, although an ancient practice, is increasingly relevant in regions where freshwater is scarce. Large pieces of mesh or netting trap tiny water droplets present in the fog, which merge to form larger droplets and are collected in storage tanks. This sustainable and passive method requires minimal energy or resources and can be employed where other water sources are scarce or polluted.
The Future of Fog Harvesting
The new technology developed by the team led by Ghosh and Schutzius is a significant advancement in fog harvesting. By addressing the issue of atmospheric pollution, this innovation opens up new possibilities for using fog as a water source, especially in regions affected by water scarcity. It also promises to make a significant impact in sectors like agriculture and reforestation, where the collected water can serve as supplemental irrigation or support young plants until they are established.
The future looks promising for fog harvesting, thanks to these scientific breakthroughs. As water scarcity continues to be a global concern, innovations like these are not just revolutionary, but also vital for humanity’s survival.