Ian Molnar

Employing Synchrotron X-Ray Microtomography to Study Silver Nanoparticle Transport Through Soils

With the rise in nanotechnology use and production, there is significant interest in understanding the potential pathways that nanoparticles may travel if released to the subsurface environment. Despite the need to better understand the behaviour of engineered nanoparticles in the subsurface environment, few tools exist that are capable of quantitatively assessing their behaviour in soil. Synchrotron x-ray computed microtomography (SXCMT) is a method of non-destructive, three-dimensional imaging and has the potential to become a powerful tool for understanding nanoparticle transport and behaviour through subsurface environments. SXCMT has the ability to create quasi-real time, high-resolution, 3-dimensional maps of nanoparticle concentrations within a wide range of porous media. These datasets can provide valuable information about nanoparticle distribution throughout the pore-network and even within each individual pore. Silver nanoparticles (nAg) are of specific interest with SXCMT because of a dearth of literature regarding nAg transport and mobility in the subsurface environment in addition to having a strong absorption K-edge in the range of radiation produced by synchrotron light sources.

Ian's project focuses on:
1) Developing a method to convert 3-dimensional x-ray absorbance datasets to silver nanoparticle concentration
2) Studying silver nanoparticle transport within a variety of soils
3) Studying other environmental contaminants with SXCMT

Personal Background

Ian graduated from the University of Western Ontario in 2007 with a Bachelor's degree in Civil and Environmental Engineering. After graduating, the opportunity to do research with RESTORE presented itself and Ian signed up immediately. Tackling some of the most pressing environmental issues was exactly what Ian was looking for and it has turned out to be an extraordinarily rewarding challenge. Ian then went on to successfully graduate from his MESc program in December 2009 before beginning the PhD program in January 2010.

Contributions

Molnar, I.L., C. S. Willson, D.M. O'Carroll, M.L. Rivers and J.I. Gerhard, 2014. A Method for Obtaining Silver Nanoparticle Concentrations Within a Porous Media via Synchrotron X-Ray Computed Microtomography, Environmental Science and Technology, doi: 10.1021/es403381s.

Molnar, I. L.; O'Carroll, D. M.; Gerhard, J. I., Impact of surfactant-induced wettability alterations on DNAPL invasion in quartz and iron oxide-coated sand systems. Journal of Contaminant Hydrology 2011, 119, (1-4), 1-12.

Molnar, I.L, Gerhard J.I., D.M. O'Carroll and C. S. Willson, 2012. Imaging the Transport of Silver Nanoparticles Through Soil With Synchrotron X-ray Microtomography. Eos, Transactions, American Geophysical Union, San Francisco, CA, Suppl., H11M-02.(Oral Presentation)

Molnar, I.L, D.M. O'Carroll C. S. Willson and , J.I. Gerhard, 2012. Employing Synchrotron X-Ray Microtomography to Study Silver Nanoparticle Transport Through Soils. International Association of Hydrogeologists, Niagara Falls, ON. (Oral Presentation)

Molnar, I.L, D.M. O'Carroll, J.I. Gerhard and C. S. Willson, 2012. Investigating Silver Nanoparticle Transport in Soil via Synchrotron X-Ray Microtomography. Mineralogical Magazine, Goldschmidt, Montreal, QC. (Oral presentation)

Molnar, I.L, D.M. O'Carroll, J.I. Gerhard and C. S. Willson, 2011. Exploring the use of synchrotron radiation to image silver nanoparticles in a porous media. Eos, Transactions, American Geophysical Union, San Francisco, CA, Suppl., H53B-1418.(Poster)

Molnar, I.L, D.M. O'Carroll, J.I. Gerhard and C. S. Willson, 2010. Impact of mineral isoelectric point on subsurface/NAPL wettability. Eos, Transactions, American Geophysical Union, San Francisco, CA, Suppl., H53C-1054. (Poster)

Molnar, I.L, O'Carroll, D.M. and Gerhard, J.I., 2009 The Wettability of a Multi-Component DNAPL on Quartz and Iron Oxide Sands. Eos, Transactions, American Geophysical Union, Jt. Assem., Toronto, ON, Suppl., H31A-06. (Poster)