Role of pre-corrosion of Fe0 on its efficiency in remediation systems: An electrochemical study

Touomo-Wouafo, Marquise; Dazie, Joel Donkeng; Btatkeu-K, Brice D.; Tchatchueng, Jean Bosco; Noubactep, Chicgoua; Ludvı́k, Jiřı́

doi:10.1016/j.chemosphere.2018.06.080

Cited by 16 publications

(9 citation statements)

References 44 publications

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“…For this reason, the H 2 O and HCl systems are presented. The results in Figure 4 corroborate previous reports [33,60,74,75] that pretreatment procedures mainly modify the availability of iron corrosion products (FeCPs). While under moderate conditions, atmospheric FeCPs are washed away, under more severe condition (e.g., HCl washed) the external layers for the metal are dissolved.…”

Section: Effect Of Materials Pretreatmentsupporting

confidence: 89%

“…The oxide scale is, in essence, a diffusion barrier, and its shielding property depends on its porosity and its adherence to the Fe 0 surface [66][67][68]. The oxide scale interacts with contaminants as well and complicates the understanding of the Fe 0 /H 2 O system [73][74][75].Many interrelated factors affect the formation and transformation of an oxide scale (e.g., Fe 0 size, surface roughness and water chemistry). The most important influencing factor is the water chemistry, including the presence of co-solutes (and ligand), the pH value, the temperature and the water flow velocity [66][67][68].…”

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confidence: 99%

“…Water treatment using Fe 0 mostly occurs at pH > 5.0, which corresponds to the range of quantitative precipitation of iron oxides [27]. In this pH range, it is very difficult to correlate the corrosion and the decontamination processes because of the omnipresence of the oxide scale [73][74][75]. The oxide scale is generated and transformed in a dynamic process ("rust never rests") [66,76].…”

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The Impact of Selected Pretreatment Procedures on Iron Dissolution from Metallic Iron Specimens Used in Water Treatment

Ndé-Tchoupé

Lufingo

et al. 2019

Sustainability

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Studies were undertaken to determine the reasons why published information regarding the efficiency of metallic iron (Fe 0 ) for water treatment is conflicting and even confusing. The reactivity of eight Fe 0 materials was characterized by Fe dissolution in a dilute solution of ethylenediaminetetraacetate (Na 2 -EDTA; 2 mM). Both batch (4 days) and column (100 days) experiments were used. A total of 30 different systems were characterized for the extent of Fe release in EDTA. The effects of Fe 0 type (granular iron, iron nails and steel wool) and pretreatment procedure (socking in acetone, EDTA, H 2 O, HCl and NaCl for 17 h) were assessed. The results roughly show an increased iron dissolution with increasing reactive sites (decreasing particle size: wool > filings > nails), but there were large differences between materials from the same group. The main output of this work is that available results are hardly comparable as they were achieved under very different experimental conditions. A conceptual framework is presented for future research directed towards a more processed understanding.Sustainability 2019, 11, 671 2 of 20 organic [27,28], fluoride [29][30][31], heavy metals [32,33], nitrate [34,35], pathogens [36][37][38] and radionuclides [32,39]. The desalination of water using Fe 0 has also been reported [40][41][42][43]. The two key advantages of Fe 0 are its affordability and its universal availability (iron nails, scrap iron and steel wool) [9,10,44,45]. It is commonly reported that the major drawback of Fe 0 -based technologies for water treatment is the low intrinsic reactivity of granular materials [28,33,46]. This situation is said to be aggravated by the inherent generation of an oxide scale at the Fe 0 surface (passivation). Countermeasures to overcome Fe 0 passivation were recently reviewed by Guan et al. [28] and further discussed by Noubactep [47]. It is recalled that, considering passivation as a "curse" contradicts the evidence that Fe 0 -based subsurface permeable barriers have been successfully working for more than one decade [48][49][50]. On the other hand, increased "passivation" should have occurred in the spongy iron filters in Antwerpen as well [2,19]. Clarifying this contradiction is certainly a progress for the whole Fe 0 technology. Clearly, an understanding of the role of "passivation" in the process of decontamination using Fe 0 should be useful for enhancing the system's efficiency in practice [30,31,47].There is an agreement on the evidence that using Fe 0 for water treatment and environmental remediation is "putting corrosion to use" [51][52][53]. There is otherwise a contradiction on practically any other aspect concerning the Fe 0 /H 2 O system, including the reaction mechanisms and factors determining the long-term efficiency of such systems [9,28,47,[54][55][56][57][58]. A key reason for this is the large variability of experimental conditions used in testing Fe 0 materials [58][59][60][61][62]. The main influencing operational parameter seems to be Fe 0 itself [58,61,63,6...

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Section: Effect Of Materials Pretreatmentsupporting

confidence: 89%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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The Impact of Selected Pretreatment Procedures on Iron Dissolution from Metallic Iron Specimens Used in Water Treatment

Ndé-Tchoupé

Lufingo

et al. 2019

Sustainability

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“…In fact, the efficiency of Fe 0 -based systems to remove pathogens and chemical contaminants from water was documented more than a century earlier [15,37]. In view of the diversity of contaminants that have been reported to be quantitatively removed in Fe 0 /H 2 O systems [38][39][40], it was stated that reduction is not likely to be a significant removal mechanism [41][42][43][44]. A decade after the first critical review severely questioning the reductive transformation concept [45], the view that Fe 0 is an own reducing agent under environmental conditions is still prevailing [46][47][48].…”

Section: (Iii) Example 3: the Sono Arsenic Filtermentioning

confidence: 99%

Water Treatment Using Metallic Iron: A Tutorial Review

Gwenzi

Sipowo-Tala

et al. 2019

Processes

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Researchers and engineers using metallic iron (Fe0) for water treatment need a tutorial review on the operating mode of the Fe0/H2O system. There are few review articles attempting to present systematic information to guide proper material selection and application conditions. However, they are full of conflicting reports. This review seeks to: (i) Summarize the state-of-the-art knowledge on the remediation Fe0/H2O system, (ii) discuss relevant contaminant removal mechanisms, and (iii) provide solutions for practical engineering application of Fe0-based systems for water treatment. Specifically, the following aspects are summarized and discussed in detail: (i) Fe0 intrinsic reactivity and material selection, (ii) main abiotic contaminant removal mechanisms, and (iii) relevance of biological and bio-chemical processes in the Fe0/H2O system. In addition, challenges for the design of the next generation Fe0/H2O systems are discussed. This paper serves as a handout to enable better practical engineering applications for environmental remediation using Fe0.

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In Situ Chemical Reduction of Chlorinated Organic Compounds

Rodrigues

Betelu

Colombano

et al. 2020

Applied Environmental Science and Engineering for a Sustainable Future

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Chlorinated organic compounds (COCs) are common anthropogenic contaminants of soil and groundwater. COCs were industrially produced for different applications, such as dry cleaning, degreasing, or as pesticides. The presence of COCs in the environment is a major concern because of their toxicity and persistence.The most widely used method for their remediation is the conventional pump-and-treat system. However, this technology can hardly achieve a complete remediation because of geological characteristics and the presence of pore space pollution/adsorbed pollution, leading to a residual saturation. Hence, in addition to the improvement of pump-and-treat systems, in situ chemical processes have been largely developed. These chemical processes involve the injection of chemical reagents for the removal of residual source pollution and/or the treatment of plume contamination. Chemical degradation of COCs can be achieved by oxidative or reductive processes. If chemical oxidation has been first developed for in situ application, chemical reduction is one of the most important emerging remediation techniques for COCs treatment. Due to the electronegative character of chlorine substituents, COCs can effectively be transformed via reductive pathways. Moreover, reductive dechlorination has shown higher efficiency on highly chlorinated compounds. This chapter focuses on the presentation of the chemical reduction of the most common COCs pollutants, followed by kinetic and mechanistic approaches related to the use of iron-based particles. Developments on in situ chemical reduction technologies in order to enhance remediation rates are also exposed. Influence of environmental conditions for in situ applications is then developed. Finally, a case study is presented.

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Role of pre-corrosion of Fe0 on its efficiency in remediation systems: An electrochemical study

Cited by 16 publications

References 44 publications

The Impact of Selected Pretreatment Procedures on Iron Dissolution from Metallic Iron Specimens Used in Water Treatment

The Impact of Selected Pretreatment Procedures on Iron Dissolution from Metallic Iron Specimens Used in Water Treatment

Water Treatment Using Metallic Iron: A Tutorial Review

In Situ Chemical Reduction of Chlorinated Organic Compounds

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