An analysis of the evolution of reactive species in Fe0/H2O systems

Noubactep, Chicgoua

doi:10.1016/j.jhazmat.2009.02.143

Cited by 135 publications

(106 citation statements)

References 37 publications

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“…It is hypothesised that the reduction and dechlorination of 2,4-DCP occurred when it adsorbed on the surface of Ni/Fe particles [14,15]. This is also consistent with Noubactep's [11,12] report about 'the adsorption/co-precipitation concept' for contaminant removal in Fe 0 /H 2 O systems. The current model for the dechlorination reaction using Ni/Fe nanoparticles involved the oxidation of iron to galvanically protected Ni [9,16].…”

supporting

confidence: 80%

“…This indicates that a fraction of organic compounds were adsorbed or covered by surface passive layers due to the precipitation of metal hydroxides on the surface of iron and Ni/Fe nanoparticles. This is also evidenced by Noubactep [11,12], who validated the 'adsorption/ co-precipitation concept' for contaminant removal in Fe 0 /H 2 O systems.…”

Section: Batch Experimental Proceduresmentioning

confidence: 73%

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Catalytic dechlorination of2,4-dichlorophenol by Ni/Fe nanoparticles in the presence of humic acid: intermediate products and some experimental parameters

Zhang

Baig

et al. 2012

Journal of Experimental Nanoscience

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The catalytic dechlorination of 2,4-dichlorophenol (2,4-DCP) by Ni/Fe bimetallic nanoparticles in the presence of humic acid (HA) was investigated in order to understand their applicability for in situ remediation of groundwater. 2,4-DCP was catalytically dechlorinated to form the final products -phenol (P) via two intermediates, o-chlorophenol (o-CP) and p-chlorophenol (p-CP). It was demonstrated that the carbon mass balances during the dechlorination were between 84% and 92%, and other carbons were adsorbed on the surface of Ni/Fe bimetallic nanoparticles. The experimental results suggest that HA competed for reaction sites on the Ni/Fe bimetallic nanoparticles with 2,4-DCP, and thus reduced the efficiency and rate of the dechlorination of 2,4-DCP. The catalytic degradation slowed down as the increase of HA in solution, and when HA's concentrations were 0, 10, 20 and 30 mg L À1, the maximum concentrations of o-CP were 0.025, 0.041, 0.039 and 0.034 mM in 10, 30, 30 and 30 min, respectively. High Ni content, low initial pH value, high Ni/Fe nanoparticles' dosage and high temperature favoured the catalytic dechlorination of 2,4-DCP. The experimental results show that no other intermediates were generated besides Cl À , o-CP, p-CP and P during the catalytic dechlorination of 2,4-DCP.

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supporting

confidence: 80%

Section: Batch Experimental Proceduresmentioning

confidence: 73%

Catalytic dechlorination of2,4-dichlorophenol by Ni/Fe nanoparticles in the presence of humic acid: intermediate products and some experimental parameters

Zhang

Baig

et al. 2012

Journal of Experimental Nanoscience

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“…This corresponds to an alternative concept introduced by Noubactep in 2006 [11,80,114,[139][140][141][142][143], but largely ignored within the Fe 0 research community [11,82]. According to Ghauch [82], only some five research groups have tested (and validated) the alternative concept worldwide.…”

Section: The Mechanism Of Cr VI Removal Revisitedmentioning

confidence: 99%

Progress in Understanding the Mechanism of CrVI Removal in Fe0-Based Filtration Systems

Gheju¹

2018

Water

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Hexavalent chromium (Cr VI ) compounds are used in a variety of industrial applications and, as a result, large quantities of Cr VI have been released into the environment due to inadequate precautionary measures or accidental releases. Cr VI is highly toxic to most living organisms and a known human carcinogen by inhalation route of exposure. Another major issue of concern about Cr VI compounds is their high mobility, which easily leads to contamination of surface waters, soil, and ground waters. In recent years, attention has been focused on the use of metallic iron (Fe 0 ) for the abatement of Cr VI polluted waters. Despite a great deal of research, the mechanisms behind the efficient aqueous Cr VI removal in the presence of Fe 0 (Fe 0 /H 2 O systems) remain deeply controversial. The introduction of the Fe 0 -based filtration technology, at the beginning of 1990s, was coupled with the broad consensus that direct reduction of Cr VI by Fe 0 was followed by co-precipitation of resulted cations (Cr III , Fe III ). This view is still the dominant removal mechanism (reductive-precipitation mechanism) within the Fe 0 remediation industry. An overview on the literature on the Cr geochemistry suggests that the reductive-precipitation theory should never have been adopted. Moreover, recent investigations recalling that a Fe 0 /H 2 O system is an ion-selective one in which electrostatic interactions are of primordial importance is generally overlooked. The present work critically reviews existing knowledge on the Fe 0 /Cr VI /H 2 O and Cr VI /H 2 O systems, and clearly demonstrates that direct reduction with Fe 0 followed by precipitation is not acceptable, under environmental relevant conditions, as the sole/main mechanism of Cr VI removal in the presence of Fe 0 .

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“…However, this is only possible when theoretical analysis and experimentation are perfectly performed. The presentation herein has recalled that for Fe 0 filters, both theoretical analysis [102,103] and experimentation [104] have been unsatisfactory. This suggests that there is a huge gap between calculations and understanding [105].…”

Section: The True Value Of Mathematical Modelingmentioning

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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An analysis of the evolution of reactive species in Fe0/H2O systems

Abstract: Aqueous contaminant removal in the presence of metallic iron (e.g.

Cited by 135 publications

References 37 publications

Catalytic dechlorination of2,4-dichlorophenol by Ni/Fe nanoparticles in the presence of humic acid: intermediate products and some experimental parameters

Catalytic dechlorination of2,4-dichlorophenol by Ni/Fe nanoparticles in the presence of humic acid: intermediate products and some experimental parameters

Progress in Understanding the Mechanism of CrVI Removal in Fe0-Based Filtration Systems

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

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