Water covers about 71 percent of the Earth’s surface, which means, despite the large amount of water present on Earth, most seawater is actually not drinkable . In fact, fresh water accounts for just 2.5 percent of the total , so much of the world tends to experience severe water shortages.
Scientists from China have reported the development of a highly efficient desalination device, which would be powered by solar energy as it consists of a layer of titanium, TiNO or titanium nitride oxide capable of absorbing this type of energy, which is deposited on a type of special paper and foam, allowing the solar absorber to float on seawater.
According to the researchers, when sunlight hits the titanium layer, it heats up very quickly and vaporizes the water . By placing the unit in a transparent container with a sloping quartz roof, the water vapor can be condensed and collected, producing a large quantity of fresh water .
In the solar energy sector, TiNO consists of a coating with absorbent qualities , widely used both in solar hot water systems and in photovoltaic units. They stand out mainly because they have a high solar absorption rate, to which is added a low thermal emission, being able to effectively convert solar energy into thermal energy .
To achieve this, the scientists developed a method to deposit a TiNO layer with the help of a technique known as magnetron sputtering, using a type of highly porous special paper (airlaid paper) that acts as an absorbent material to deliver water from the seawater tank, which is made with wood fibers and is very commonly used, since it is commonly used in the manufacture of disposable diapers.
The evaporation unit included a total of three parts: a TiNO layer located on top, a thermal insulator formed by polyethylene foam (characterized by having many air-filled pores capable of trapping heat and allowing the unit to multilayer can float on a seawater tank), and the paper itself located at the bottom.
The salinity of ordinary seawater is over 75,000 milligrams of salt per liter, while ordinary drinking water has a salinity of around 200 milligrams per liter.
According to the researchers, the desalination unit was able to lower the salinity of seawater to less than 2 milligrams per liter , which would demonstrate that this technology would have the potential to help solve the world’s freshwater shortage , by combining low cost, high efficiency and lack of fouling.
