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Low-Pressure Polymer Immobilization Methods to Reduce Contaminant Leaching from Deep Vadose Zone Sands.

Authors :
Aleman Zeledon, Alina Mauxira
Song, Jinhu
Johnson, Drew W.
Huang, Jie
Saslow, Sarah
Source :
Journal of Geotechnical & Geoenvironmental Engineering. Oct2024, Vol. 150 Issue 10, p1-13. 13p.
Publication Year :
2024

Abstract

Water-reactive polymer grouts can be injected directly into contaminated sediment zones where a portion of the contaminated pore water may participate in grout polymerization and contaminants may be immobilized in the grout matrix. This study evaluated the effectiveness of injecting a water-reactive polymer grout into frozen soil for immobilizing iodide by incorporation into grouted soil monoliths. Iodide was used as a model sediment contaminant. Soil freezing is a unique method used in subsurface remediation and was investigated because it may limit the amount of contaminated water displaced and mobilized during pressure grouting. In addition, joint use of grouting and soil freezing has the potential to broadly impact other remediation challenges, for example, treatment of collapsible soil and soil in water-active areas. Variables analyzed were freezing, moisture content, iodide concentration, and accumulated pressure due to carbon dioxide gas generated during polymerization. Iodide mobilization, iodide leaching as cumulative fraction leached (CFL), effective diffusivity (D), and leachability index (LI) were evaluated. Iodide mobilized during polymer injection into frozen sands was 37.9%±12.9% which indicated that soil freezing did not prevent iodide from being mobilized when injecting the liquid polymer. Lowering the moisture content from 5% to 1.6% by weight, to align reacted water with the introduced polymer, resulted in a decrease in the mobilization of iodide to only 0.23%±0.06%. This is the lowest reported result for contaminant displacement from liquid reaction additions known to the authors. All grouted samples leached less and more slowly than the ungrouted (control) samples. Grouting reduced effective iodide diffusivity by more than 96% and the LI of the grouted soil monoliths was greater than 6.0, which meets the criteria for materials intended for shallow burial with radioisotopes. These results demonstrate that polymer grouting of sands can be used to immobilize and slow the subsurface transport of sediment contaminants. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
10900241
Volume :
150
Issue :
10
Database :
Academic Search Index
Journal :
Journal of Geotechnical & Geoenvironmental Engineering
Publication Type :
Academic Journal
Accession number :
179021746
Full Text :
https://doi.org/10.1061/JGGEFK.GTENG-12159