Environmental Implications of Nanotechnology

 cysteine-capped Zn-sulfide clusterEnvironmental nanotechnology involves the application of nanoscale materials for environmental contexts (such as treatment and remediation) and the study of potential environmental, health, and safety risks of nanotechnology. The Hsu-Kim group is actively involved in both the study of environmental applications and the implications of nanotechnology.

 In the first case, we are studying the use of nanoscale zero valent iron (and variants of this material) for in-situ remediation of contaminated sediments. Zero valent iron (ZVI) is well known for its ability to foster reductive degradation of hazardous compounds, such as chlorinated solvents. The application of hydrophobic halogenated compounds such as brominated flame retardants has also been proposed; however, successful application of this approach is challenging due to low contact between the ZVI particles and the target compound. Through opportunities with the Duke University Superfund Research Center, we are exploring improvements of ZVI-based materials for the degradation of brominated flame retardants, the mechanisms of degradation, and possible synergies (or antagonisms) with microbial biodegradation pathways.

While the unique reactivities associated with nanomaterials lend to new and exciting applications, the potential risks of the materials must also be explored at the same time. In this respect, our group has studied the major processes that influence the fate of metal and mineral-based nanomaterials. This work has involved a variety of materials, including metallic silver, zinc oxide, cerium dioxide, and metal sulfides. An overarching theme of this work is that reactivity of the materials (e.g. surface composition, dissolution, redox chemistry, bioavailability) can be linked to fundamental concepts of metal speciation. Much of our work has investigated the interactions between the nanoparticles and natural organic matter (NOM), with special focus on ligand functional groups that may be controlling sorption of NOM to these nanomaterials, and subsequently aggregation, deposition and solubility of the nanoparticles.

We closely collaborate with other researchers who are part of the Center for Environmental Implications of NanoTechnology (CEINT), headquartered at Duke.

 

 

Recent publications:

ES&T Special Issue: Nanoscale Organic Matter Interactions and Feature Article (2011);

Metal sulfides: ES&T (2008, 2009, 2011); Chemical Geology (2012); JCIS (2010);

Metallic silver: ES&T (2012), (2012), (2014), Ecotoxicology (2016), Nanotoxicology (2015)

Soluble Metal Oxides and dissolution kinetics: ESPI (2014), ES&T (2015) (2017)

Effects of nanoparticles on aquatic passive samplers: ES&T (2015)

 

This research is funded by the National Science Foundation, the National Institute for Environmental Health Sciences, and the Center for the Environmental Implications of NanoTechnology (CEINT).