Loading…

Influence of gravity on transport and retention of representative engineered nanoparticles in quartz sand

Four types of NPs: carbon nanotubes and graphene oxide (carbon-based NPs), titanium dioxide and zinc oxide metal-oxide NPs, were utilized to systematically determine the influence of gravity on the transport of NPs in porous media. Packed column experiments for two types of carbon-based NPs were per...

Full description

Saved in:
Bibliographic Details
Published in:Journal of contaminant hydrology 2015-10, Vol.181, p.153-160
Main Authors: Cai, Li, Zhu, Jinghan, Hou, Yanglong, Tong, Meiping, Kim, Hyunjung
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Four types of NPs: carbon nanotubes and graphene oxide (carbon-based NPs), titanium dioxide and zinc oxide metal-oxide NPs, were utilized to systematically determine the influence of gravity on the transport of NPs in porous media. Packed column experiments for two types of carbon-based NPs were performed under unfavorable conditions in both up-flow (gravity-negative) and down-flow (gravity-positive) orientations, while for two types of metal-oxide NPs, experiments were performed under both unfavorable and favorable conditions in both up-flow and down-flow orientations. Both breakthrough curves and retained profiles of two types of carbon-based NPs in up-flow orientation were equivalent to those in down-flow orientation, indicating that gravity had negligible effect on the transport and retention of carbon-based NPs under unfavorable conditions. In contrast, under both unfavorable and favorable conditions, the breakthrough curves for two types of metal-oxide NPs in down-flow orientation were lower relative to those in up-flow orientation, indicating that gravity could decrease the transport of metal-oxide NPs in porous media. The distinct effect of gravity on the transport and retention of carbon-based and metal-oxide NPs was mainly attributed to the contribution of gravity to the force balance on the NPs in quartz sand. The contribution of gravity was determined by the interplay of the density and sizes of NP aggregates under examined solution conditions. [Display omitted] •Effect of gravity on four types of NPs was studied in both up- and down-flow modes.•Gravity had negligible effect on the transport and retention of carbon-based NPs.•Gravity could decrease the transport (increased retention) of metal-oxide NPs.•Role of gravity depends on the interplay of aggregate sizes and density of NPs.
ISSN:0169-7722
1873-6009
DOI:10.1016/j.jconhyd.2015.02.005