When you drink a nice refreshing glass of water, do you ever think, "Gee, I'm glad that polymeric desalination membrane did its job!" Probably not, but maybe you should.
Those thin polyamide, or plastic-like, membranes work as filters that turn salty water into fresh drinkable water. The salt-blocking membranes are widely used to turn both slightly salty water (brackish water) and seawater into fresh water.
Enter Devin Shaffer, UH assistant professor of civil and environmental engineering. He's developed a breakthrough membrane that lets water flow through up to eight times faster while still keeping out salt, making desalination more efficient and accessible than ever before.
Shaffer's work, published in ACS Applied Materials & Interfaces, addresses the tradeoff between how much water can pass through (permeability) and how well the membrane blocks salt and other impurities (selectivity). If the membrane lets more water through, it may also allow more salt to pass, reducing effectiveness. If it blocks more salt, it may slow down water flow, making the process less efficient and more expensive in systems like reverse osmosis and nanofiltration.
"We have developed a new type of ultrathin polyamide membrane with a unique, contorted structure that creates more open spaces, or enhanced free volume, within the material," reports Shaffer.
"These new ultrathin contorted membranes break that trade-off by letting water through much faster without sacrificing salt rejection, making desalination systems more efficient and cost-effective," he said.
Ultimately, with these new developments, desalination could become even faster and more energy-efficient, lowering costs and making clean water more accessible, Shaffer said.
