Making fresh water
The Earth is a watery planet but most of its water is not fit to drink. Only 2 percent of its water is fresh, trapped in its glaciers, rivers and lakes. The drinking water crisis on the planet with its six-billion (and growing) population, is assuming serious dimensions with fears that in the 21st century — tions will go to war over fresh water like some tions did over oil in the earlier century. In the midst of such gloomy speculations, news has come of a team of US engineers discovering a material for cost-effectively removing salt from seawater. The material, a nometer-thick sheet of molybdenum disulfide (MoS2), is riddled with tiny holes called nopores. These have the wonderful property of letting through high volumes of seawater but keeping out its salt. The team at the University of Illinois experimented with various thin-film membranes and found that MoS2 showed the greatest efficiency, filtering through up to 70 percent more water than graphene membranes. Hopes are now bright that this breakthrough will lays the foundation for next generation materials which aid desalition. Most available desalition technologies at present rely on reverse osmosis to push seawater through a thin plastic membrane to make fresh water, but its yield is little and the process expensive as well as energy intensive. The Illinois University team is claiming it can make its technology cheaper and membranes more efficient and failure-proof in the long run.