Ramanan, B., Holmes, W.M. , Sloan, W.T. and Phoenix, V.R. (2012) Investigation of nanoparticle transport inside coarse-grained geological media using magnetic resonance imaging. Environmental Science and Technology, 46(1), pp. 360-366. (doi: 10.1021/es2012726) (PMID:22091923)
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Publisher's URL: http://dx.doi.org/10.1021/es2012726
Abstract
Quantifying nanoparticle (NP) transport inside saturated porous geological media is imperative for understanding their fate in a range of natural and engineered water systems. While most studies focus upon finer grained systems representative of soils and aquifers, very few examine coarse-grained systems representative of riverbeds and gravel based sustainable urban drainage systems. In this study, we investigated the potential of magnetic resonance imaging (MRI) to image transport behaviors of nanoparticles (NPs) through a saturated coarse-grained system. MRI successfully imaged the transport of superparamagnetic NPs, inside a porous column composed of quartz gravel using T2-weighted images. A calibration protocol was then used to convert T2-weighted images into spatially resolved quantitative concentration maps of NPs at different time intervals. Averaged concentration profiles of NPs clearly illustrates that transport of a positively charged amine-functionalized NP within the column was slower compared to that of a negatively charged carboxyl-functionalized NP, due to electrostatic attraction between positively charged NP and negatively charged quartz grains. Concentration profiles of NPs were then compared with those of a convection-dispersion model to estimate coefficients of dispersivity and retardation. For the amine functionalized NPs (which exhibited inhibited transport), a better model fit was obtained when permanent attachment (deposition) was incorporated into the model as opposed to nonpermanent attachment (retardation). This technology can be used to further explore transport processes of NPs inside coarse-grained porous media, either by using the wide range of commercially available (super)paramagnetically tagged NPs or by using custom-made tagged NPs.
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Sloan, Professor William and Holmes, Dr William and Phoenix, Dr Vernon |
Authors: | Ramanan, B., Holmes, W.M., Sloan, W.T., and Phoenix, V.R. |
College/School: | College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience College of Science and Engineering > School of Engineering > Infrastructure and Environment College of Science and Engineering > School of Geographical and Earth Sciences > Geography |
Journal Name: | Environmental Science and Technology |
Journal Abbr.: | EST |
Publisher: | American Chemical Society |
ISSN: | 0013-936X |
ISSN (Online): | 1520-5851 |
Published Online: | 18 November 2011 |
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