Influence of permeability on nanoscale zero-valent iron particle transport in saturated homogeneous and heterogeneous porous media

The growing use of nanoscale zero-valent iron (NZVI) in the remediation of contaminated groundwater raises concerns regarding its transport in aquifers. Laboratory-scale sand-packed column experiments were conducted with bare and sucrose-modified NZVI (SM-NZVI) to improve our understanding of the transport of the nanoparticles in saturated porous media, as well as the role of media size, suspension injection rate and concentration on the nanoparticle behavior. As the main indicative parameters, the normalized effluent concentration was measured and the deposition rate coefficient (k) was calculated for different simulated conditions. Overall, compared to the high retention of bare NZVI in the saturated silica column, SM-NZVI suspension could travel through the coarse sand column easily. However, the transport of SM-NZVI particles was not very satisfactory in a smaller size granular matrix especially in fine silica sand. Furthermore, the value of k regularly decreased with the increasing injection rate of suspension but increased with suspension concentration, which could reflect the role of these factors in the SM-NZVI travel process. The calculation of k-value at the tests condition adequately described the experimental results from the point of deposition dynamics, which meant the assumption of first-order deposition kinetics for the transport of NZVI particles was reasonable and feasible.

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Transport characteristics of nanoscale zero-valent iron carried by three different “vehicles” in porous media

Journal of Environmental Science and Health Part A ◽

10.1080/10934529.2014.951214 ◽

2014 ◽

Vol 49 (14) ◽

pp. 1639-1652 ◽

Cited By ~ 8

Author(s):

Yan Su ◽

Yong S. Zhao ◽

Lu L. Li ◽

Chuan Y. Qin ◽

Fan Wu ◽

...

Keyword(s):

Porous Media ◽

Zero Valent Iron ◽

Nanoscale Zero Valent Iron

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Hydrodynamic controls on particle transport through heterogeneous porous media. Technical progress report

10.2172/10133202 ◽

1992 ◽

Author(s):

S.E. Silliman

Keyword(s):

Porous Media ◽

Technical Progress ◽

Particle Transport ◽

Heterogeneous Porous Media ◽

Progress Report

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Surface coating with Ca(OH)2 for improvement of the transport of nanoscale zero-valent iron (nZVI) in porous media

Water Science & Technology ◽

10.2166/wst.2013.494 ◽

2013 ◽

Vol 68 (10) ◽

pp. 2287-2293 ◽

Cited By ~ 11

Author(s):

Cai-jie Wei ◽

Xiao-yan Li

Keyword(s):

Porous Media ◽

Surface Coating ◽

Coating Layer ◽

Zero Valent Iron ◽

Mass Ratio ◽

Batch Experiments ◽

Effective Protection ◽

Transmission Electron ◽

Nanoscale Zero Valent Iron ◽

Protection Layer

A novel thermal deposition method was developed to coat Ca(OH)2 on the surface of nanoscale zero-valent iron (nZVI). The nZVI particles with the Ca(OH)2 coating layer, nZVI/Ca(OH)2, had a clear core-shell structure based on the transmission electron microscopy observations, and the Ca(OH)2 shell was identified as an amorphous phase. The Ca(OH)2 coating shell would not only function as an effective protection layer for nZVI but also improve the mobility of nZVI in porous media for its use in environmental decontamination. A 10% Ca/Fe mass ratio was found to result in a proper thickness of the Ca(OH)2 shell on the nZVI surface. Based on the filtration tests in sand columns, the Ca(OH)2-based surface coating could greatly improve the mobility and transport of nZVI particles in porous media. In addition, batch experiments were conducted to evaluate the reactivity of Ca(OH)2-coated nZVI particles for the reduction of Cr(VI) and its removal from water.

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