Start
Apr 28, 2011 - 16:00
End
Apr 28, 2011 - 17:00
Venue
Creativity hall (Room 118) Chemical Eng.
Event Type
Speaker
Dr. Subhasis Ghoshal Associate Professor and William Dawson Scholar Department of Civil Engineering McGill University Montreal Canada
Title
Nanoparticles for Groundwater Remediation
Abstract: Chlorinated solvents such as trichloroethylene tetrachloroethylene and carbon tetrachloride are used in large volumes by various industries. Uncontrolled or accidental discharges of chlorinated solvents into the subsurface have led to extensive contamination of groundwater aquifers. Chlorinated solvents are extremely toxic and even trace quantities in the groundwater render the water unsafe for use. To date remediation efforts to restore groundwater to meet drinking water standards have not been successful at any large chlorinated solvent-contaminated site and thus there is an urgent need for development of new effective remediation technologies. Nanoparticles of zero valent iron (NZVI) can degrade chlorinated organic compounds very rapidly to innocuous products such as ethane and chloride ions. This makes NZVI an excellent reactant for cleaning up chlorinated solvent-contaminated sites. Recent studies have however shown that bare NZVI when injected into the ground through wells are able to migrate only a few feet from the wells because they get filtered out by the soil. This result is not intuitive given that a large fraction of the pores in subsurface granular media are much larger than the nanoparticles. Modifying the surfaces of NZVI with polymers however shows significantly improved mobility in groundwater. The presentation will discuss the characteristics of polymer-stabilized NZVI that enhance it transport in subsurface porous media. Results from controlled laboratory studies will show how NZVI surface characteristics aqueous solution chemistry sand grain characteristics influences the mobility of polymer-stabilized NZVI. Given the high mobility of polymer-stabilized NZVI the remaining challenges and opportunities for NZVI-based remediation technologies for groundwater remediation will be discussed.Brief bio: Subhasis Ghoshal is an Associate Professor of Civil Engineering and a William Dawson Scholar (Research Chair) in Soil and Groundwater Remediation at McGill University. His research investigates the impacts of petroleum oils and organic solvents on groundwater quality and the performance of remediation technologies. He joined McGill after completing his Ph.D. at Carnegie Mellon University Pittsburgh PA and a postdoctoral fellowship at the University of Michigan at Ann Arbor. In 2010 he was appointed by the Minister of the Environment Government of Canada as a member of a high level scientific advisory panel to evaluate the environmental impacts of oil sands operations in Canada. He is directing a large multi-investigator research program on the use of nanoparticles for remediation of contaminated aquifers.