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

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• 作者：Kamaljit Singh ; Robert K. Niven ; Timothy J. Senden ; Michael L. Turner ; Adrian P. Sheppard ; Jill P. Middleton ; Mark A. Knackstedt
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：April 15, 2011
• 年：2011
• 卷：45
• 期：8
• 页码：3473-3478
• 全文大小：888K
• 年卷期：v.45,no.8(April 15, 2011)
• ISSN：1520-5851

文摘

The pore-scale behavior of a nonaqueous phase liquid (NAPL) trapped as residual contamination in a porous medium, subject to freeze鈭抰haw cycles, was investigated by X-ray microcomputed tomography. It is shown that freeze鈭抰haw 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鈭抙ydrocarbon systems on the Earth and other planets.