Agar agar-stabilized milled zerovalent iron particles for in situ groundwater remediation

Velimirović, Milica; Schmid, Doris; Wagner, Stephan; Micić, Vesna; Kammer, Frank von der; Hofmann, Thilo

doi:10.1016/j.scitotenv.2015.11.007

Cited by 33 publications

(25 citation statements)

References 58 publications

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“…We should note that these micron-scale aggregates would still considered as nanomaterials at these dimensions by the European Union as they are composed of individual particles <100 nm as noted in E.U recommendation 2011/696/EU. Similar observations have also been noted for other iron based nanoparticles synthesised by abiotic processes 38 , 39 , and both Vander Waal forces and magnetic forces could contribute to these phenomena 40 . In this study, the coatings were added after biosynthesis of the BNM particles from ferrihydrite.…”

Section: Discussionsupporting

confidence: 85%

Optimising the transport properties and reactivity of microbially-synthesised magnetite for in situ remediation

Joshi

Liu

Watts

et al. 2018

Sci Rep

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Engineered nanoparticles offer the potential for remediation of land and water that has been contaminated by organics and metals. Microbially synthesized nano-scale magnetite, prepared from Fe(III) oxides by subsurface Fe(III)-reducing bacteria, offers a scalable biosynthesis route to such a nano-scale remediation reagent. To underpin delivery of “bionanomagnetite” (BNM) nanomaterial during in situ treatment options, we conducted a range of batch and column experiments to assess and optimise the transport and reactivity of the particles in porous media. Collectively these experiments, which include state of the art gamma imaging of the transport of 99m Tc-labelled BNM in columns, showed that non-toxic, low cost coatings such as guar gum and salts of humic acid can be used to enhance the mobility of the nanomaterial, while maintaining reactivity against target contaminants. Furthermore, BNM reactivity can be enhanced by the addition of surface coatings of nano-Pd, extending the operational lifetime of the BNM, in the presence of a simple electron donor such as hydrogen or formate.

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Section: Discussionsupporting

confidence: 85%

Optimising the transport properties and reactivity of microbially-synthesised magnetite for in situ remediation

Joshi

Liu

Watts

et al. 2018

Sci Rep

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“…Particle transport and deposition are fundamental phenomena behind several natural and engineered processes. One of the many examples is the fate of pollutants in groundwater systems, an emerging environmental issue countered with interventions based on the injection of nanoscopic zero-valent iron particles, to cite a particular successful application [1,2,3]. More in general, the study of solute deposition is of central importance in filtration processes to enhance air and water quality [4], chromatographic systems, catalytic cells and packed bed reactors [5,6,7], enhanced oil recovery techniques [8], and even drug delivery studies [9,10]: all these processes rely on a detailed understanding of how transported solutes/particles flow through a porous matrix and interact with it.…”

Section: Introductionmentioning

confidence: 99%

A robust upscaling of the effective particle deposition rate in porous media

Boccardo

Crevacore

Sethi

et al. 2018

Journal of Contaminant Hydrology

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In the upscaling from pore-to continuum (Darcy) scale, reaction and deposition phenomena at the solid-liquid interface of a porous medium have to be represented by macroscopic reaction source terms. The effective rates can be computed, in the case of periodic media, from three-dimensional microscopic simulations of the periodic cell. Several computational and semi-analytical models have been studied in the field of colloid filtration to describe this problem. They often rely on effective deposition rates defined by simple linear reaction ODEs, neglecting the advection-diffusion interplay, and assuming slow reactions (or large Péclet numbers). Therefore, when these rates are inserted into general macroscopic transport equations, they can lead to conceptual inconsistencies and, therefore, often qualitatively wrong results. In this work, we study the upscaling of Brownian deposition on face-centred cubic (FCC) spherical arrangements using a linear effective reaction rate, defined by volume averaging, and a macroscopic advection-diffusion-reaction equation. The case of partial deposition, defined by an attachment probability, is studied and the limit of ideal deposition is retrieved as a particular case. We make use of a particularly convenient computational setup that allows the direct computation of the asymptotic stationary value of effective rates. This allows to drastically reduce the computational domain down to the scale of the single repeating periodic unit: the savings are ever more noticeable in the case of higher Péclet numbers, when larger physical times are needed to reach the asymptotic regime, and thus, equivalently, a much larger computational domain and simulation time would be needed in a traditional setup. We show how this new definition of deposition rate is more robust and extendable to the whole range of Péclet numbers; it also is consistent with the classical heat and mass transfer literature.

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“…6,7 Various natural and synthetic polymeric materials such as guar gum, xanthan gum, starch, agar agar, poly(acrylic acid) (PAA), Tween-20, polyelectrolytes (polystyrene sulphonate and polyaspartate), organic matter and CMC have been used to improve the stability, reactivity and mobility of NZVI in porous media. [8][9][10][11][12][13][14][15][16] These polymers can interact with NZVI particles and prevent aggregation by reducing particle-particle attractive forces which can increase repulsion between the particles and the porous medium. 3 Important properties such as stabilizing capacity and shear thinning exhibited by xanthan gum deemed the latter to be a suitable material for NZVI particle mobility and aggregation studies.…”

Section: 5mentioning

confidence: 99%

“…NZVI-biopolymer stabilization and degradation of environmental pollutants Table 1 summarizes comparative results of different biopolymers used for the stabilization of NZVI and their efficiencies towards the degradation of the pollutants. 16,35,43,[48][49][50][51][52][53][54][55][56][57][58][59][60] Extensive studies have demonstrated that both polymers and surfactants are effective in inhibiting NZVI aggregation and enhancing mobility in the subsurface for emplacement. The major factors which inuence stabilization of NZVI, namely surface modi-cation, emulsication and conjugation with polymer, have also proved able to provide protection to NZVI against aggregation and surface oxidation, in addition to promoting transport in subsurface environments.…”

Section: Figmentioning

confidence: 99%

Gum karaya (Sterculia urens) stabilized zero-valent iron nanoparticles: characterization and applications for the removal of chromium and volatile organic pollutants from water

et al. 2017

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This paper illustrates a method for the stabilization of nanoscale zerovalent iron (NZVI) suspensions with a "green" biopolymer, Gum Karaya (GK). The stability, sedimentation, aggregation behavior and reactivity towards Cr(VI) and volatile organic compounds using NZVI-GK (GK stabilized NZVI) and bare NZVI, were assessed. The stabilization mechanism of NZVI-GK was demonstrated using ATR-FTIR, XRD, XPS, TEM, SEM, TGA and particle size analysis. The NZVI-GK nanoparticle suspension was found to be stable for at least three months, suggesting a superior stability rendering property of GK which forms a scaffold to prevent NZVI from aggregating. Batch experiments, centred on Cr(VI) reduction and degradation of volatile organic compounds, confirmed that NZVI-GK was more reactive than bare NZVI. Furthermore, XPS and ICP-MS results revealed that Cr(VI) was reduced to Cr(III) by NZVI-GK and the remaining Cr(III) insolution was adsorbed onto GK, thereby completely removing chromium from the contaminated water.Our study suggests that an important role is played due to the attributes of GK (which include nontoxicity, biodegradability and cost-effectiveness) in conjunction with the ability of NZVI to remove all chromium viz. [Cr(VI) and Cr(III)] coupled with the total degradation and removal of VOCs (cis-1,2-dichloroethene, perchloroethene and trichloroethene) from water.

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Agar agar-stabilized milled zerovalent iron particles for in situ groundwater remediation

Cited by 33 publications

References 58 publications

Optimising the transport properties and reactivity of microbially-synthesised magnetite for in situ remediation

Optimising the transport properties and reactivity of microbially-synthesised magnetite for in situ remediation

A robust upscaling of the effective particle deposition rate in porous media

Gum karaya (Sterculia urens) stabilized zero-valent iron nanoparticles: characterization and applications for the removal of chromium and volatile organic pollutants from water

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