John Hoffman (Phillip Group)

Dual-Functionalized Nanofiltration Membranes Exhibit Multifaceted Anti-Fouling and Ion Rejection Performance

February 20, 2019

John Hoffman is a third-year graduate student in the Water purification and Advanced Transport Engineering Research (WATER) Laboratory. He presented "Dual-Functionalized Nanofiltration Membranes Exhibit Multifaceted Anti-Fouling and Ion Rejection Performance," at the ND Energy PD&GS Luncheon in February.

John Hoffman

The WATER Lab is led by Prof. William Phillip, associate professor of chemical and biomolecular engineering.  The group’s research focuses on membrane separations, which can be a more energy efficient method of water purification compared to traditional processes such as distillation.

Through a controlled reaction process, the group attempts to expand the performance and selectivity of copolymer nanofiltration membranes.

“We can take a membrane with high permeability and increase the functionality to have an additional reaction to reject something like salt from seawater,” Hoffman said.

Improvements to the desalination process can be vital in increasing freshwater reserves in places threatened by water scarcity such as Cape Town, South Africa or the western United States.

These systems can also be used for heavy metal recovery. Hoffman cited the situation in Flint, Michigan where 100,000 residents were exposed to dangerous levels of lead in their drinking water.

Hoffman’s hometown of Toledo, Ohio experienced a water shortage in 2014 with the Lake Erie algae crisis. For a few days, residents were unable to use their tap water, and the disruption served as a wake-up call.

“It kind of opened my eyes that some people have to deal with this issue every day of their lives,” Hoffman said.

Specifically, Hoffman targets fouling, a process by which the life expectancy of membranes can be rapidly reduced by contaminants in waste streams.

“We try to incorporate anti-fouling properties, as well as increase the ion selectivity by putting in charge functionalities on the pore wall,” Hoffman said. It is important to find a balance, he added, as too much charge functionality can actually make the fouling worse.

While an undergraduate student at the University of Toledo, Hoffman conducted a research project dealing with anti-fouling for medical applications. This work with similar polymeric surface coatings provided background knowledge and an interest in the field when he came to Notre Dame for graduate school. 

Hoffman praised the University’s broad range of research opportunities, which allow students to address the kinds of challenges, such as access to clean water, that directly impact millions of people.

“We should have the ability to solve this, and we need to continue to push the boundaries on what we can achieve with membranes,” Hoffman said.