Collaborative Research: Transformation, interaction and toxicity of emerging 2D nanomaterials free-standing and embedded onto nanocomposite membranes for PFAS degradation

Per- and polyfluoroalkyl substances (PFAS) are a class of chemical compounds containing strong carbon-fluorine bonds and have been produced for public and industrial usage since the 1940s. The detection of these chemicals in various environmental matrices and living organisms (including humans) along with their high stability and toxicogenic potential have raised significant public health concerns.

Conventional water and wastewater treatment processes are ineffective at removing and degrading these chemicals due to their highly stable carbon-fluorine bonds along with varying hydrophobicity and polarity. The goal of this proposed project is to design a new class of reactive nanocomposite membrane filters that will simultaneously separate these compounds from water and degrade them to less- or non-toxic byproducts.

To achieve this goal, the principal investigators will combine expertise from nanomaterials, membrane separations, and ecotoxicity using novel planar two-dimensional nanomaterials to fabricate catalytic nanofiltration membranes with high water flow rate, stability, and antifouling properties. This will enable removal and degradation of these chemicals which are priority pollutants as well as other emerging chemicals in this family of compounds.

At the same time, the 2D nanomaterials and resulting byproducts will be tested for their toxicity to model organisms to determine the sustainability and effectiveness of this new treatment process. The successful completion of this project will benefit society through the development of fundamental knowledge about the new 2D nanomaterials and their interactions with these fluorinated compounds for the development of an integrated membrane reactor system that could serve both as a centralized water treatment system and a point-of-use filter for the treatment of water contaminated with these compounds.

This project will further benefit society through education and training of underrepresented undergraduate and graduate students. This project is jointly funded by the CBET Nanoscale Interactions Program and the Established Program to Stimulate Competitive Research (EPSCoR).

The goal of this project is to develop a fundamental understanding for the sustainable design of 2D inorganic photocatalytic membranes for effective degradation of the priority persistent pollutants of emerging concern, Per- and polyfluoroalkyl substances. Novel 2D nanomaterials with differing electronic and physicochemical properties, non-metallic phosphorene and metalloid hexagonal boron nitride that have shown evidence for degradation of these compounds, will be employed.

This research project aims to address the knowledge gap on how these properties affect transformation, stability, and toxicity of the 2D hexagonal boron nitride and phosphorene nanosheets in free-standing form in aqueous media and after incorporating them onto nanocomposite membranes. The research team will examine the degradation potential of the 2D nanomaterials and their mechanisms of interactions with these compounds, identify breakdown products, and evaluate toxicity of their degradation products using a model organism, Caenorhabditis elegans, to verify that the breakdown products are less toxic than the initial chemicals.

To achieve this, state-of-the-art nanoscale characterization techniques, molecular and thermodynamic modeling, analytical chemistry, and molecular biology techniques will be employed. Findings will provide knowledge about the potential transformation of non-carbon 2D nanomaterials and the overall stability of 2D nanomaterials which will be useful to understanding other non-carbon 2D materials with varied electronic and physicochemical properties.

Furthermore, while the chemistry of blending non-carbon 2D nanomaterials onto polymeric membranes for the removal and destruction of emerging water pollutants is the focus here, the same chemistry can be used to fabricate air filtration membranes that would be able to potentially capture and destroy airborne toxins, such as viruses. This project will also strengthen the ongoing educational and outreach activities of the principal investigators by integrating research and education, mentoring undergraduate and graduate students, reaching out to community organizations, and engaging underrepresented students in STEM fields.

Technology dissemination to end users will be accomplished through peer-reviewed manuscripts and conference presentations. This project is jointly funded by the CBET Nanoscale Interactions Program and the Established Program to Stimulate Competitive Research (EPSCoR).

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.