Remobilization of Residual Non-Aqueous Phase Liquid in Porous Media by Freeze - Thaw Cycles

Date

2011

Authors

Singh, Kamaljit
Niven, Robert
Senden, Timothy
Turner, Michael
Sheppard, Adrian
Middleton, Jill
Knackstedt, Mark

Journal Title

Journal ISSN

Volume Title

Publisher

American Chemical Society

Abstract

The pore-scale behavior of a nonaqueous phase liquid (NAPL) trapped as residual contamination in a porous medium, subject to freeze-thaw cycles, was investigated by X-ray microcomputed tomography. It is shown that freeze-thaw cycles cause significant NAPL remobilization in the direction of the freezing front, due to the rupture and transport of a significant proportion of (supposedly entrapped) larger multipore NAPL ganglia. Significant NAPL remains in place, however, due to substantial ganglion fragmentation into single- and subpore ganglia. The contraction of branched ganglia into more rounded forms, especially near the top surface, is also observed. Three freezing-induced mechanisms are proposed to explain the results. The findings have important implications for NAPL contamination in cold regions, and for the behavior of water-hydrocarbon systems on the Earth and other planets.

Description

Keywords

Keywords: Cold regions; Freeze-thaw cycles; Hydrocarbon systems; Microcomputed tomography; NAPL contamination; Nonaqueous phase liquids; Porous Media; Porous medium; Remobilization; Top surface; Computerized tomography; Freezing; Hydrocarbons; Liquids; Porous mater

Citation

Source

Environmental Science and Technology

Type

Journal article

Book Title

Entity type

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Restricted until

2037-12-31