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Transport of Surface-modified Carbon Nanotubes through a Soil Column
Published on: April 2, 2015
Colloid transport in a heterogeneous partially saturated sand column
Mikhail Mishurov1, Alexander Yakirevich, Noam Weisbrod
1Department of Environmental Hydrology and Microbiology, Zuckerberg Institute for Water Research, J. Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sede Boker Campus, 84990, Israel.
Environmental Science & Technology
|March 21, 2008
Summary
Heterogeneous soil columns with preferential pathways show faster colloid transport but increased recovery at intermediate flow rates. Maximum colloid recovery is not always linked to maximum water content in such soils.
Area of Science:
- Environmental Science
- Soil Science
- Colloid Science
Background:
- Colloid transport in soil is crucial for contaminant and nutrient movement.
- Soil heterogeneity significantly influences fluid and particle dynamics.
- Understanding colloid behavior in unsaturated conditions is vital for environmental modeling.
Purpose of the Study:
- To investigate colloid transport in unsaturated heterogeneous sand columns.
- To evaluate the impact of preferential pathways on colloid arrival time and recovery.
- To determine the relationship between flow rate, soil heterogeneity, and colloid recovery.
Main Methods:
- Constructed heterogeneous sand columns with fine sand preferential pathways in coarse sand.
- Performed experiments under unsaturated steady-state flow conditions at varying rates (0.1, 0.2, 0.4 cm/min).
- Simultaneously introduced microspheres (1, 0.2, 0.02 µm) and soluble tracers (LiBr).
Main Results:
- Preferential pathways reduced colloid front-arrival time by approximately twofold.
- Colloid recovery was highest at an intermediate flow rate (0.2 cm/min), not the highest.
- Hydrodynamic modeling confirmed maximum solution flux between sand layers at 0.2 cm/min, explaining recovery patterns.
Conclusions:
- Soil heterogeneity and flow dynamics interact to control colloid transport and recovery.
- Maximum colloid recovery in heterogeneous soils may not correlate with maximum water content.
- Findings have significant implications for predicting colloid transport in complex natural soil environments.
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