Stabilization of highly concentrated suspensions of iron nanoparticles using shear-thinning gels of xanthan gum

Comba, Silvia; Sethi, Rajandrea

doi:10.1016/j.watres.2009.05.046

Cited by 187 publications

(116 citation statements)

References 41 publications

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“…The magnetic attractive forces and van der Waals forces are known to affect the aggregation and gelation between nZVI particles, causing precipitation in the water environment (Comba and Sethi 2009). Phenrat et al (2007) indicated that nZVI particles can aggregate to micrometer-size aggregates and precipitate from solution rapidly.…”

Section: Discussionmentioning

confidence: 99%

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Characterization of preferential flow paths between boreholes in fractured rock using a nanoscale zero-valent iron tracer test

et al. 2016

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Recent advances in borehole geophysical techniques have improved characterization of cross-hole fracture flow. The direct detection of preferential flow paths in fractured rock, however, remains to be resolved. In this study, a novel approach using nanoscale zero-valent iron (nZVI or 'nano-iron') as a tracer was developed for detecting fracture flow paths directly. Generally, only a few rock fractures are permeable while most are much less permeable. A heat-pulse flowmeter can be used to detect changes in flow velocity for delineating permeable fracture zones in the borehole and providing the design basis for the tracer test. When nano-iron particles are released in an injection well, they can migrate through the connecting permeable fracture and be attracted to a magnet array when arriving in an observation well. Such an attraction of incoming iron nanoparticles by the magnet can provide quantitative information for locating the position of the tracer inlet. A series of field experiments were conducted in two wells in fractured rock at a hydrogeological research station in Taiwan, to test the cross-hole migration of the nano-iron tracer through permeable connected fractures. The fluid conductivity recorded in the observation well confirmed the arrival of the injected nano-iron slurry. All of the iron nanoparticles attracted to the magnet array in the observation well were found at the depth of a permeable fracture zone delineated by the flowmeter. This study has demonstrated that integrating the nano-iron tracer test with flowmeter measurement has the potential to characterize preferential flow paths in fractured rock.

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Section: Discussionmentioning

confidence: 99%

“…Iron is a magnetic material which can be attracted by a magnet. Previous studies revealed that iron nanoparticles would be highly mobile and remain in suspension for days to months in unconsolidated deposits (Sun et al 2007;Comba and Sethi 2009;Bennett et al 2010;He et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Characterization of preferential flow paths between boreholes in fractured rock using a nanoscale zero-valent iron tracer test

et al. 2016

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“…They are generally suspended in a colloidal dispersion and stabilized by a biopolymer [60,61] or a surfactant and, thanks to the highly specific surface area, can degrade contaminants faster than (commercial) millimetric Fe 0 . Several degradation pathways can occur at the surface of the NZVI, which generally lead to the reduction of the contaminant and the consumption and oxidation of the metallic core (Figure 8).…”

Section: Reaction With Nanoscale Zero Valent Ironmentioning

confidence: 99%

Nanomaterials for the Abatement of Pharmaceuticals and Personal Care Products from Wastewater

2018

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Abstract:In this short-review, the most common types of both pharmaceutical and personal care products (PPCP, a class of "emerging pollutants") are considered, as well as some of the most frequent methods for their removal that envisage the use of nanomaterials. The nanomaterials used in conservative methods (namely, reverse osmosis, nanofiltration and adsorption) are basically nanoporous solids. Non-conservative methods, which include photocatalysis and Fenton reaction, are currently considered more promising than conservative ones, as the former allow the (at least) partial degradation of the original molecules into more biodegradable by-products, which can be further abated by subsequent biological treatments, whereas the former are not efficient for the removal of small quantities of pollutants and have to be regenerated.

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“…Owing to their shear thinning characteristics, these fluids can enhance the distribution of entrained amendments into lower permeability zones, thereby enhancing the remediation processes (Chokejaroenrat et al, 2013;Kananizadeh et al, 2015;Silva et al, 2013;Zhong et al, 2008Zhong et al, , 2011). STFs have been tested and applied as a means to deliver dissolved remedial amendments (Chokejaroenrat et al, 2013(Chokejaroenrat et al, , 2014Kananizadeh et al, 2015;Smith et al, 2008;Truex et al, 2015;Zhong et al, 2008Zhong et al, , 2011Zhong et al, , 2013 or reactive particles (Comba and Sethi, 2009;Dalla Vecchia et al, 2009;Oostrom et al, 2007;Tiraferri et al, 2008;Truex et al, 2011a,b) to the subsurface for the purpose of enhancing remediation effectiveness.…”

Section: Introductionmentioning

confidence: 99%

Delivery of vegetable oil suspensions in a shear thinning fluid for enhanced bioremediation

Zhong

Truex

Kananizadeh

et al. 2015

Journal of Contaminant Hydrology

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In situ anaerobic biological processes are widely applied for dechlorination of chlorinated solvents in groundwater. A wide range of organic substrates have been tested and applied to support the dechlorination processes. Vegetable oils are a promising type of substrate and have been shown to induce effective dechlorination, have limited geochemical impacts, and maintain good longevity. Because they are non-aqueous phase liquids, distribution of vegetable oils in the subsurface has typically been approached by creating emulsified oil solutions for injection into the aquifer. In this study, inexpensive waste vegetable oils were suspended in a shear-thinning xanthan gum solution as an alternative approach for delivery of vegetable oil to the subsurface. The stability, oil droplet size distribution, and rheological behavior of the oil suspensions that are created in the xanthan solutions were studied in batch experiments. The injectability of the suspensions and the oil distribution in a porous medium were evaluated in column tests. Numerical modeling of oil droplet transport and distribution in porous media was conducted to help interpret the columntest data. Batch studies showed that simple mixing of vegetable oil with xanthan solution produced stable suspensions of the oil as micron-size droplets. The mixture rheology retains shear-thinning properties that facilitate improved uniformity of substrate distribution in heterogeneous aquifers. Column tests demonstrated successful injection of the vegetable oil suspension into a porous medium. This study provides evidence that vegetable oil suspensions in xanthan gum solutions have favorable injection properties and are a potential substrate for in situ anaerobic bioremediation.Published by Elsevier B.V.

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Stabilization of highly concentrated suspensions of iron nanoparticles using shear-thinning gels of xanthan gum

Cited by 187 publications

References 41 publications

Characterization of preferential flow paths between boreholes in fractured rock using a nanoscale zero-valent iron tracer test

Characterization of preferential flow paths between boreholes in fractured rock using a nanoscale zero-valent iron tracer test

Nanomaterials for the Abatement of Pharmaceuticals and Personal Care Products from Wastewater

Delivery of vegetable oil suspensions in a shear thinning fluid for enhanced bioremediation

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