Investigating dominant processes in ZVI permeable reactive barriers using reactive transport modeling

Weber, Anne; Ruhl, Aki Sebastian; Amos, Richard T.

doi:10.1016/j.jconhyd.2013.05.001

Cited by 30 publications

(19 citation statements)

References 54 publications

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“…10b and Figure S6) The majority of corroded iron still precipitated as ferrous hydroxide. The carbonate and calcium mass balance, however, indicates the formation of both calcium carbonate and iron carbonate species (based on the reaction stoichiometry of calcium carbonate (CaCO 3 ) (Weber et al, 2013)). This was also observed in experiments with a lower nZVI content in the column ( Figure S6 and Figure S7a).…”

Section: Mass Balancesmentioning

confidence: 99%

“…Corrosion experiments with granular iron have indicated that the formation of mineral precipitates affect the long-term reactivity of PRB (Kober et al, 2002;Klausen et al, 2003;Kohn et al, 2005;Parbs et al, 2007;Weber et al, 2013). In particular, mainly iron hydroxide carbonate (chukanovite, Fe 2 CO 3 (OH) 2 ) is formed in the presence of carbonate on the iron surface (Ruhl et al, 2011) and influences significantly the reactivity (Jeen et al, 2006;Lee and Wilkin, 2010;Ruhl et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Influences of nanoscale zero valent iron loadings and bicarbonate and calcium concentrations on hydrogen evolution in anaerobic column experiments

2015

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Section: Mass Balancesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influences of nanoscale zero valent iron loadings and bicarbonate and calcium concentrations on hydrogen evolution in anaerobic column experiments

2015

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“…The approach conventionally used in the Fe 0 water filtration literature [16,19,[27][28][29][30] is not derived from Equation (10) and related simplifications. Moreover, the presentation above reveals that chemical reactions yielding contaminants reductive transformation in Fe 0 /H 2 O systems (Equations (3) and (4)) are included in just one of seven processes making up the dynamics of oxide scale formation and transformation.…”

Section: Oxide Scale Formation and Its Effects On K Iron : Modeling Amentioning

confidence: 99%

“…Alternative strategies have been discussed in [16,19,[27][28][29][30]. These alternative strategies are based on Equation (1) and mentioned herein for the sake of completeness.…”

Section: Introductionmentioning

confidence: 99%

Predicting the Hydraulic Conductivity of Metallic Iron Filters: Modeling Gone Astray

Noubactep

2016

Water

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Abstract:Since its introduction about 25 years ago, metallic iron (Fe 0 ) has shown its potential as the key component of reactive filtration systems for contaminant removal in polluted waters. Technical applications of such systems can be enhanced by numerical simulation of a filter design to improve, e.g., the service time or the minimum permeability of a prospected system to warrant the required output water quality. This communication discusses the relevant input quantities into such a simulation model, illustrates the possible simplifications and identifies the lack of relevant thermodynamic and kinetic data. As a result, necessary steps are outlined that may improve the numerical simulation and, consequently, the technical design of Fe 0 filters. Following a general overview on the key reactions in a Fe 0 system, the importance of iron corrosion kinetics is illustrated. Iron corrosion kinetics, expressed as a rate constant k iron , determines both the removal rate of contaminants and the average permeability loss of the filter system. While the relevance of a reasonable estimate of k iron is thus obvious, information is scarce. As a conclusion, systematic experiments for the determination of k iron values are suggested to improve the database of this key input parameter to Fe 0 filters.

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“…The observed reduction in ZVI reactivity with time, associated with PRBs, has been attributed to clogging of the pore space by precipitates, or gas discharge from the ZVI, or blocking of the reactive iron surface by precipitates, (e.g., [111,112]). Passivation of the Fe surface by Fe III (oxy)hydroxide coatings has been interpreted as the cause of a loss of reactivity (e.g., [113]).…”

Section: E42 Impact Of Zvi Ageing On Reactivitymentioning

confidence: 99%

ZVI (Fe0) Desalination: Stability of Product Water

Antia¹

2016

Resources

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A batch-operated ZVI (zero valent iron) desalination reactor will be able to partially desalinate water. This water can be stored in an impoundment, reservoir or tank, prior to use for irrigation. Commercial development of this technology requires assurance that the partially-desalinated product water will not resalinate, while it is in storage. This study has used direct ion analyses to confirm that the product water from a gas-pressured ZVI desalination reactor maintains a stable salinity in storage over a period of 1-2.5 years. Two-point-three-litre samples of the feed water (2-10.68 g (Na + + Cl´)¨L´1) and product water (0.1-5.02 g (Na + + Cl´)¨L´1) from 21 trials were placed in storage at ambient (non-isothermal) temperatures (which fluctuated between´10 and 25˝C), for a period of 1-2.5 years. The ion concentrations (Na + and Cl´) of the stored feed water and product water were then reanalysed. The ion analyses of the stored water samples demonstrated: (i) that the product water salinity (Na + and Cl´) remains unchanged in storage; and (ii) the Na:Cl molar ratios can be lower in the product water than the feed water. The significance of the results is discussed in terms of the various potential desalination routes. These trial data are supplemented with the results from 122 trials to demonstrate that: (i) reactivity does not decline with successive batches; (ii) the process is catalytic; and (iii) the process involves a number of steps.

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Investigating dominant processes in ZVI permeable reactive barriers using reactive transport modeling

Cited by 30 publications

References 54 publications

Influences of nanoscale zero valent iron loadings and bicarbonate and calcium concentrations on hydrogen evolution in anaerobic column experiments

Influences of nanoscale zero valent iron loadings and bicarbonate and calcium concentrations on hydrogen evolution in anaerobic column experiments

Predicting the Hydraulic Conductivity of Metallic Iron Filters: Modeling Gone Astray

ZVI (Fe0) Desalination: Stability of Product Water

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