Impact of Porous Media Grain Size on the Transport of Multiwalled Carbon Nanotubes
Nikolai Mattison, Denis O'Carroll, R. K. Rowe, Elijah J. Petersen
Nanomaterials possess unique physical, electrical and chemical properties which make them attractive for use in a wide range of applications. Through their use and eventual disposal, nanomaterials may ultimately be released into the subsurface environment and previous studies show that nanomaterials are hazardous to life. This study investigates the mobility of one important nanomaterial (multi-walled carbon nanotubes or MWNTs) through porous media. Particular focus is placed on the impact of varying mean collector grain size (d50) on MWNT retention. Results from one dimensional column experiments conducted under various physical and chemical conditions coupled with results of numerical modeling assess the suitability of traditional transport models to predict MWNT mobility. MWNTs were found to be mobile though porous media ranging from fine sand to silt. Findings suggest that a dual deposition model coupled with site blocking greatly improves model fits compared to traditional colloid filtration theory.