From metal-contaminated water and soil, to sewage sludge, to diesel fuel combustion and beyond, the Environmental Nanoscience group focuses on trying to understand the behavior of natural and engineered inorganic nanomaterials in complex environments. We collaborate with scientists in universities and national labs around the world. We are a member of the NSF-funded Center for the Environmental Implications of Nanotechnology (CEINT) alongside Duke University, the University of Kentucky, Howard University, Stanford University, and Carnegie Mellon. We are also part of VTSuN, the Virginia Tech Center for Sustainable Nanotechnology. VTSuN is a multi-department, interdisciplinary research center focused on advancing nanoscale science and engineering with an emphasis on environmental sustainability.
NANOPARTICLE STRUCTURE-PROPERTY RELATIONSHIPS
In nature or in the laboratory, nanosized particles exhibit interesting electronic, magnetic, physical and chemical properties, and reactivity relative to their bulk counterparts. In addition, their large amount of reactive surface area makes them important components of (geo)chemical systems. These interesting properties of nanosized materials, typically having a characteristic dimension from 1 to 100 nm, are inextricably related to their size, shape, composition, and atomic structure. Marc Michel's research focuses on developing a comprehensive understanding of these fundamental attributes of nanoparticles and in understanding their size/shape/composition/
Platinum group element (PGE)-based nanocatalysts are important in a variety of industrial and technological processes ranging from catalytic conversion of CO, hydrocarbons, and NOx in modern automobiles to energy production by hydrogen fuel cells. These technological innovations have had - and will continue to have – a tremendous impact on our environment in terms of global climate change, and soil, water, and air quality. Rui's research focuses on understanding how atomic structural, physical, and chemical characteristics relate to the electrocatalytic activity of a highly reactive, commercially sourced platinum (Pt)nanocatalyst known as platinum “black” (Pt-black).
METAL NANOPARTICLES IN COMPLEX MEDIA
As a result of the rapid development of nanotechnology, it is important to get better insights into the occurrence, transport, transformation and possible risks related to nanoparticles released into the environment. Wastewater and atmospheric deposition (dry/wet) are considered as typical inputs of nanoparticles into the environment. Yi Yang and collaborators are working on the behavior of nanoparticles and the interaction with other contaminants, such as trace metals along their transport in sewer systems. This research has important implications for ecotoxicological studies of nanoparticles and is an integral part of CEINT.
CERIA NANOPARTICLES IN DIESEL ADDITIVES
Nanoparticulate cerium oxide's (n-ceria) ability to catalyze diesel combustion leading to increased fuel economy and reduced emissions has been well studied for decades. Unfortunately, the potential for environmental impact has seen their use restricted. James Dale, in collaboration with Professor Linsey Marr and Steve Cox (VT CEE), aims to identify and characterize n-ceria from commercially available additives before and after combustion in a diesel engine. This information will aid in modeling the dispersion and predicting environmental deposition of n-ceria if it were to be put into widespread use.
The role of microorganisms in mineral formation has long been recognized. What is not adequately appreciated, however, is that a significant portion of these biogenic minerals initially occur and/or remain as nanoscale particles in nature. Jie Xu is systematically studying a range of nano-metal-sulfides to understand their reactivity in terms of photochemistry, redox reactions, dissolution, and transformations in the environment. The results of these studies have important implications for a myriad of geological, environmental, and industrial processes as well as materials science and biomedical applications.
[Biogenic minerals project]
MANGANESE OXIDE COATINGS IN WATER FILTER MEDIA
Most drinking water treatment plants use rapid separation methods (e.g. flocculation), filtration, and chlorination for the removal of Mn and other contaminants from water. During the operation, incoming insoluble Mn particles and soluble Mn (II) ions from the raw water promote manganese oxide surface coatings on the filter media. This has been observed for many years and is known to be the major Mn removal mechanism; however, no detailed mechanism has been investigated at the nano-scale where the reactions occur. Michel Vargas is attempting to determine this mechanism experimentally using analytical transmission electron microscopy based nano-scale structural/chemical characterization techniques.