CAREER: Targeted Catalytic Reduction of Persistent Organohalogens in Wastewater using a Novel V2C MXene-Imprinted Polymer Composite

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).

Organohalogens such as polychlorinated biphenyls (PCBs) and per- and polyfluoroalkyl substances (PFAS) pose significant environmental and human health risks due to their toxicity, chemical stability, and persistence in the environment. The effective removal and destruction of organohologen pollutants by water treatment will require novel and targeted approaches as these compounds are often present at very dilute concentrations in drinking water sources.

Treatment technologies which generate reactive solvated electrons (SE) are promising approaches to degrade organohalogens in aqueous solutions via chemical reduction. However, the efficacy of a SE-based water treatment process is hindered by competing reactions with co-occurring contaminants and interfering reactions between solvated electrons and dissolved organic/inorganic species present in drinking water sources.

The overarching goal of this CAREER project is to design, synthesize, characterize, and evaluate new composite media capable of targeted separation and catalytic reductive dehalogenation to address the limitations of current SE-based water treatment processes. The successful completion of this project will benefit society through the generation of new water treatment media and fundamental knowledge to advance the development and deployment of more efficient and cost-effective technologies to remove and destroy organohalogen pollutants from drinking water sources.

Further benefits to society will be achieved through student education and training including the mentoring of a graduate student and five undergraduate students at the University of Washington.

Organohalogens such as PCBs and PFAS are extremely stable in natural and engineered aquatic systems. They are also resistant to degradation using conventional biological and chemical water treatment processes. The generation of solvated electrons in aqueous solutions is a promising approach to cleave carbon-halide bonds and facilitate organohalogen degradation/destruction in contaminated drinking water sources.

However, solvated electrons (SE) are easily scavenged and may not react with the targeted organohalogen pollutants as they may be consumed by other co-contaminants and dissolved organic/inorganic species which often exist in drinking water sources. This CAREER project will address the critical limitations of current SE-based water treatment processes for organohalogen removal.

To advance this goal, the Principal Investigator (PI) will explore the development of new composite media consisting of 1) molecularly imprinted polymer shells that can selectively extract organohalogens and 2) vanadium carbide catalytic cores with demonstrated potential to generate solvated electrons and degrade organohalogens. The specific objectives of the research include: (1) media design, synthesis, and characterization, (2) measurements of media sorption capacity and selectivity, (3) experimental investigations of media catalytic activity, (4) evaluation of media performance in complex water matrices in the presence of competing dissolved organic/inorganic species; and (5) evaluation of media reusability.

The successful completion of this project has the potential for transformative impact through the generation of fundamental knowledge to advance the development and deployment of more efficient and cost-effective media to remove organohalogen contaminants from drinking water sources. To implement the educational and training goals of this CAREER project, the PI will lead a newly developed seminar course for senior-level undergraduate and graduate students about organohalogen properties, exposure, toxicity, and remediation.

Additionally, the PI and her students plan to partner with the Duwamish Valley Youth Corps to design a culturally appropriate workshop outlining unique organohalogen exposure pathways and risks closely associated with indigenous lifestyles including subsistence and dietary practices.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.