Title
Fate and transport of sulfidated nano zerovalent iron (S-nZVI): A field study
Author
Garcia, A. Nunez
Boparai, H.K.
de Boer, C.V.
Chowdhury, A.I.A.
Kocur, C.M.D.
Austrins, L.M.
Herrera, J.
O'Carroll, D.M.
Publication year
2020
Abstract
Treatment of nano zerovalent iron (nZVI) with lower valent forms of sulfur compounds (sulfidation) has the potential to increase the selectivity and reactivity of nZVI with target contaminants and to decrease inter-particle aggregation for improving its mobility. These developments help in addressing some of the long-standing challenges associated with nZVI-based remediation treatments and are of great interest for in situ applications. Herein we report results from a field-scale project conducted at a contaminated site. Sulfidated nZVI (S-nZVI) was prepared on site by first synthesizing carboxymethyl cellulose (CMC) stabilized nZVI with sodium borohydride as a reductant and then sulfidating the nZVI suspension by adding sodium dithionite. Transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy (EDS) of CMC-S-nZVI, from synthesis barrels, confirms the presence of both discrete spherical nZVI-like particles (∼90 nm) as well as larger irregular structures (∼500 nm) comprising of iron sulfides. This CMC-S-nZVI suspension was gravity fed into a sandy material and monitored through multiple multi-level monitoring wells. Samples collected from upstream and downstream wells suggest very good radial and vertical iron distribution. TEM-EDS analysis from the recovered well samples also indicates the presence of both nZVI-like particles as well as the larger flake-like structures, similar to those found in the injected CMC-S-nZVI suspension. This study shows that S-nZVI stabilized with CMC can be safely synthesized on site and is highly mobile and stable in the subsurface, demonstrating for the first time the field applicability of S-nZVI. © 2019 Elsevier Ltd
Subject
Geological Survey Netherlands
2015 Energy
Characterization
Dithionite
Field application
Nano zerovalent iron
Subsurface transport
Sulfidation
To reference this document use:
http://resolver.tudelft.nl/uuid:e67b1712-4ef7-41a7-98d0-ee850af62497
DOI
https://doi.org/10.1016/j.watres.2019.115319
TNO identifier
870495
Publisher
Elsevier Ltd
ISSN
0043-1354
Source
Water Research, 170, 1-10
Article number
115319
Document type
article