Transport and mobilization of multiwall carbon nanotubes in quartz sand under varying saturation
2014 (English)In: Environmental Earth Sciences, ISSN 1866-6280, Vol. 71, no 8, 3751-3760 p.Article in journal (Refereed) Published
In this study, a series of sand packed columnswere used to investigate the mobility of multiwall carbonnanotubes (MWCNTs) in unsaturated porous media underunfavorable conditions for deposition. The flow throughcolumn experiments were designed to assess water content,flow rate, and grain size effect on the mobility ofMWCNTs. It was found that variation in water content hadno significant effect on retention of MWCNTs until it waslowered to 16 % effective saturation. Thick water films,high flow rate, and repulsive forces between MWCNTs andporous media made MWCNTs highly mobile. Differentporous media grain sizes (D50 = 150–300 lm) were usedin this study. The mobility of MWCNTs slightly decreasedin finer grain sands, which was deemed to be an effect ofincrease in surface area and the number of depositionalsites, in combination with low-pore water velocity. However,physical straining was not observed in selected finegrainsands and aspect ratio of MWCNTs had low impacton mobility. Variations in pore-water velocity were producedby both changes in water saturation and in flow rate.At high pore-water velocities, the MWCNTs were generallymobile. However, for the combination of low-porewater velocity with either low water saturation or smallgrain size, some retention of MWCNTs was observed.Hence, low velocity in combination with flow throughsmaller pores increased MWCNT deposition.
Place, publisher, year, edition, pages
2014. Vol. 71, no 8, 3751-3760 p.
MWCNTs, Mobility, Unsaturated porous media, Water content, Flow rate
Oceanography, Hydrology, Water Resources
IdentifiersURN: urn:nbn:se:uu:diva-209263DOI: 10.1007/s12665-013-2769-1ISI: 000333475800038OAI: oai:DiVA.org:uu-209263DiVA: diva2:656521