Drinking water sucked from the dusty desert air using Hybrid Hydrogel

Researchers have developed an inexpensive hydrogel-based material which efficiently captures moisture even from low-humidity air and then releases it on demand. Globally, Earth's air contains almost 13 trillion tons of water, a vast renewable reservoir of clean drinking water. Many Researchers were trying to develop various materials and devices to tap this water source. But they are not much use, because they are either too inefficient, expensive or complex for practical use. Now a Saudi Research Team has developed a prototype device to finally change that. At the heart of the device is calcium chloride which is a cheap, stable and nontoxic salt,. This salt can dissolve itself by absorbing moisture from the air. It has a high affinity for water that it will absorb so much vapor from the surrounding air that eventually a pool of liquid forms. Though the Calcium chloride has great water-harvesting potential, it was not much useful previously. Because it turns from a solid to a salty liquid after absorbing water. Systems that use liquid sorbents are very complicated. To overcome the problem, the researchers incorporated the salt into a polymer called a hydrogel, which can hold a large volume of water while remaining solid. They also added a small number of carbon nanotubes to ensure the captured water vapor could be released. Carbon nanotubes very efficiently absorb sunlight and convert the captured energy into heat. The team incorporated 35 grams of this material into a simple prototype device. Left outside overnight, it captured 37 grams of water on a night when the relative humidity was around 60 percent. The following day, after 2. 5 hours of natural sunlight irradiation, most of the sorbed water was released and collected inside the device. The hydrogel's most notable aspects are its high performance and low cost. If the prototype were scaled up to produce 3 liters of water per day--the minimum water requirement for an adult--the material cost of the adsorbent hydrogel would be as low as half a cent per day. The researcher's next step will be to fine-tune the absorbent hydrogel so that it releases arrested water continuously rather than in batches