Advanced Membranes Improve Water Treatment
Increasing need for fresh water around the globe is driving the research of W.S. Winston Ho, professor of chemical and biomolecular engineering and materials science and engineering, who is fabricating a new polymer membrane to develop an efficient and compact water desalination system with higher production rates and lower costs.
The membrane allows a greater than 100 percent increase in the flow of water through it compared with the industry standard Film-Tec FT-30 membrane while maintaining a high sodium chloride salt rejection rate of more than 99 percent.
Ho and his students developed an advanced membrane fabrication technique in which a diamine solution with a hydrophilic additive is incorporated into the interfacially polymerized thin film of the membrane to increase the hydrophilicity. The additive provides an additional pathway for the reverse osmosis across the membrane, resulting in a high flux of water as well as the high salt rejection rate.
Ho’s team worked with an industrial partner to scale up this membrane to the commercial size of 42 inches in width and 2,000 feet in length. The U.S. Bureau of Reclamation, which is among the nation’s largest wholesalers of water and producers of hydroelectric power, earlier this year tested the commercial-size membrane at the Brackish Groundwater National Desalination Research Facility in Alamogordo, N.M., and the initial findings are promising, Ho says.
“The results have shown that this membrane has outperformed the best state-of-the-art commercial membrane, including an approximately 35 percent higher water production rate,”he says.
These membranes, once fully developed, could be used in the desalination of sea water to produce drinking water, such as for Navy ships or for Middle Eastern countries; in water purification; and in wastewater treatment.
