Benny Freeman Boosts Access to Clean Water
Professor Benny Freeman’s team has developed a chlorine-tolerant membrane to simplify the desalination process that removes salt from water, increasing access to fresh water and possibly reducing greenhouse gases.
“If we make the desalination process more efficient with better membranes, it will be less expensive to desalinate a gallon of water, which will expand the availability of clean water around the world,” Freeman said.
Freeman worked primarily with James E. McGrath of Virginia Tech University and Ho Bum Park of the University of Ulsan in South Korea for more than three years to develop a special membrane, made of sulfonated copolymers, that permits chlorine to pass through.
Chlorine must be added to water to disinfect it. The chemical also prevents bacteria from forming which damages membranes. Because currently used membranes do not tolerate chlorine, water must first be chlorinated, then de-chlorinated before passing through membranes and chlorinated yet again before going into the water supply network.
“This newly developed membrane promises to eliminate de-chlorination steps that are currently required to protect membranes from attack by chlorine in water,” Freeman said. “We believe that even a small increase in efficiency should result in large cost savings.”
The development could also have a direct impact on reducing carbon-dioxide emissions, which contribute to climate change.
“Energy and water are inherently connected,” Freeman added. “You need water to generate power (cooling water for electric power generation stations) and the production of pure water requires energy. That energy is often generated from the burning of fossil fuels, which inevitably leads to the creation of carbon dioxide. Therefore, if we can make desalination more energy-efficient by developing better membranes, such as those that we are working on, we can reduce the carbon footprint required to produce pure water.”
Freeman holds the Kenneth A. Kobe Professorship in Chemical Engineering and the Paul D. & Betty Robertson Meek & American Petrofina Foundation Centennial Professorship in Chemical Engineering. Funding for this research was provided by the Office of Naval Research and the National Science Foundation-Partnerships for Innovation Program.