Vijay T. John, Chemical and Biomolecular Engineering, Tulane University, 300 Lindy Boggs Bldg., New Orleans, LA 70118, Jingjing Zhan, Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118, and Gerhard Piringer, Department of Earth and Environmental Science, Tulane University, New Orleans, LA 70118.
Effective in situ remediation of contaminated groundwater plume requires the successful delivery of reactive iron particles through soil. This study reports the transport characteristics of nanoscale zero-valent iron particles that are encapsulated in porous silica sub-micron particles through a novel aerosol-assisted technology. These particles can be transported through model soils more efficiently than commercially available reactive nanoscale iron particles (RNIPs). Column tests show the composite particles elute readily while RNIP is trapped at the inlet of the column. Capillary experiments further prove that RNIP clogs the pores due to rapid aggregation, but pore plugging does not occur for the composite particles. The partitioning characteristic of the particles was investigated by a novel capillary video microscopy technique. Our results again indicate that the iron/silica composite particles preferentially accumulate and localize at the TCE/water interface, making dechlorination more efficient. Such particles with enhanced mobility hold promise for in situ ground water remediation.