University of Illinois engineers have found an energy-efficient material for removing salt from seawater. The material, a nanometer-thick sheet of molybdenum disulfide (MoS2) riddled with tiny holes called nanopores, is specially designed to let high volumes of water through but keep salt and other contaminates out, a process called desalination. The researchers modeled various thin-film membranes and found that MoS2 showed the greatest efficiency, filtering through up to 70 percent more water than graphene membranes. “Even though we have a lot of water on this planet, there is very little that is drinkable,” says professor of mechanical science and engineering Narayana Aluru. “If we could find a low-cost, efficient way to purify sea water, we would be making good strides in solving the water crisis. Most available desalination technologies rely on a process called reverse osmosis to push seawater through a thin plastic membrane to make fresh water. The membrane has holes in it small enough to not let salt or dirt through, but large enough to let water through. They are very good at filtering out salt, but yield only a trickle of fresh water.