Current Research Topics

Catalytic Membranes for Water Treatment

Conventional treatment processes fall short in addressing emerging contaminants in drinking water. Catalysts are capable of selectively treating recalcitrant contaminants to innocuous byproducts, but they currently suffer from several limitations. Catalysts are often composed of expensive elements, which puts their cost outside the low-cost requirement of drinking water treatment. Furthermore, catalysts are often operated in packed bed reactors (PBRs), which have an overall rate that is limited by diffusive mass transfer. Permeable membranes offer a viable solution to these problems. Our functional polymeric membranes can be engineered to accept single-atom catalysts, and because the transport of contaminants is driven by convection, there are no mass transfer limitations.

Adsorptive Membranes for PFAS in Water

Similar to catalysts, full-scale adsorption processes (e.g., granular activated carbon) suffer from mass transfer limitations and the inability to selectively remove contaminants. To circumvent these limitations, we are design adsorptive membranes derivatized with selective moieties. Various configurations of these membrane can be used at scale, including flat sheets, spiral-wound sheets, and hollow-fibers.

Thermal Treatment of PFAS

Wastes that are contaminated with per- and polyfluoroalkyl substances (PFAS or PFASs) pose a challenge because they cannot be safely landfilled or incinerated. Incineration may not be completely destroy PFAS, producing undesirable byproducts. We are addressing this issue by using unique analytical methods to track the fate of PFAS in thermal treatment systems and by using cost-effective catalysts to destroy PFAS at temperatures below 500 C.

PFAS Contamination of Pavements

Military firefighter training exercises using aqueous film-forming foams (AFFFs) have occurred since the 1950s. The AFFFs contained large amounts of various PFAS, and thus many of these pavement training grounds are now severely contaminated. We are addressing this problem in two ways. We are investigating the leaching of PFAS from pavements that occurs during precipitation events. This helps us understand the extent and timeline of the contamination. We are also developing thermal treatment methods for the sustainable end-of-life management of these pavements.

Micro- and Nanoplastics

Micro- and nanoplastics (MNPs) are emerging contaminants of which we have little knowledge. They come from consumer products and end up in the environment during their use and disposal. Detection and quantification of the nano fraction (<1000 nm) is difficult. In collaboration with Dr. Ken Kuno's lab in Chemistry, we are developing a new tool for detecting, identifying chemical composition, and quantifying nanoplastics in environmental samples.

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This information will be used to better understand their behavior and occurrence in the environment and to develop water treatment technologies. We are currently working with Dr. Julie Peller at Valparaiso University to develop a new coagulation and separation process for nanoplastics.

Abiotic Transformation of PFAS

There are numerous polyfluroalkyl substances that serve as precursors to terminal perfluoroalkyl acids (PFAAs). We hypothesize that portion of the PFAAs found in the environment are due to the transformation of precursors through chemical or photochemical reactions.