Junjie Niu, assistant professor of materials science & engineering in UWM’s College of Engineering & Applied Science, was awarded the college’s Outstanding Faculty Research Award for the 2018-19 academic year.
Niu and his 12-person research team at UWM are partnering with many Milwaukee-area companies on several projects with the goals of decontaminating water and decreasing water and energy consumption. Specifically, they are engineering new ways to remove contaminants from drinking water and water that is discharged from sewage lines into the environment; they also are creating self-cleaning coatings that, when applied to a range of surfaces, lessen the need for cleaning.
“In the United States and worldwide, water treatment is the big topic of our time,” says Niu, who was associate editor of the international journal RSC Advances, a publication of the Royal Society of Chemistry. “There are different approaches to these issues. My background is interdisciplinary and I combine chemistry, physics and materials science in my research.”
Niu’s current team at UWM includes two post doctoral researchers, three doctoral students, one master’s student, one research scientist and several undergraduates.
Removing PFAS from water
Working with companies including A.O. Smith, Niu is developing hybrid materials to chemically degrade per- and polyfluoroalkyl substances (PFAS). “My strategy is to develop novel adsorbents that remove short-chain fluorinated molecules and other organic molecules from water,” he says.
PFAS are man-made chemicals that were used in industry and consumer products worldwide starting in the 1950s. Although they were banned by the Environmental Protection Agency, they persist in the environment—meaning they do not break down naturally. Exposure can cause adverse health effects.
Suppressing bacteria, viruses, gases in water
Working with two local companies, Niu is researching biocides capable of suppressing water-borne, toxic strains of E. coli and other bacteria. According to Niu, the biocides that his group is developing contain bio-degradable polymers, which can prevent gram negative (such as E. coli) and legionella) gram positive (such as B. subtilis) bacteria nucleation and growth on various surfaces such as metal, plastic and glass.
The biocides could be used to coat residential water systems (filters and pipes). Application to underwater camera lenses, ship engines and even fish tanks, he says, would prevent biofilm and decrease maintenance costs.
In other research, he is engineering hybrid materials that remove from water several heavy metals (including lead, cadmium, arsenic, mercury and copper), earth metals (including calcium) gases (including chlorine) and viruses.
Provisional patents filed on “smart” self-cleaning coatings
Niu has filed two U.S. provisional patents on hydrophobic and hydrophilic coatings. Three companies have licensed these technologies. A super-hydrophobic coating, he says, is self cleaning. It repels water and activates when wet. It could be applied to the surfaces of building glass, car windshields, even toilets for example, lessening the need for cleaning and saving energy and water. “A non-flushing toilet would save millions of gallons of water per year,” says Niu, who is working with industry on a coating for ceramic toilets that would negate the need to flush urine.
Other research: Improving sensor sensitivity, battery life
Working on a project funded by SSI Technologies, in Janesville, Niu’s group has already developed a hydrophilic surface than can improve sensor sensitivity. “The signal resolution of the sensor is greatly improved after it is covered with our smart coating,” he says.
In other research, Niu is investigating longer-lasting, higher-energy batteries. Working with battery companies including Johnson Controls (now Clarios), and national labs including Oak Ridge and Argonne, he is researching the electrochemical reactions of lithium-ion batteries in situ, discerning at the atomic level the fundamental properties of the electrode materials.
The electrode active material is “the key” to higher-performing batteries, says Niu. “The goal,” he says, “is to deliver greatly improved energy density to power large electronic devices such as laptops, cell phones and electric vehicles.”