Decontamination of Hexavalent Chromium-Polluted Waters: Significance of Metallic Iron Technology

Gheju, Marius

doi:10.1007/978-3-319-55423-5_7

Cited by 8 publications

(13 citation statements)

References 249 publications

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“…Hoover and Masseli also noticed an increase in pH of the column effluent, compared to the influent, and that hydrogen was generated during the process [13]. In spite of all these interesting observations, re-established later by numerous researchers [14], the mechanism of Cr VI removal was not addressed in the work of Hoover and Masseli [13]. However, it can be assumed that they have considered the reduction of Cr VI to Cr III by Fe 0 (direct reduction) as a main mechanism involved in Cr VI removal, as widely used in the cementation process [15,16].…”

Section: Introductionmentioning

confidence: 93%

“…In this context, hundreds of papers were published in the last 20 years, mostly attempting to [14]: (1) study the influence of operational parameters on the efficiency of Cr VI removal in Fe 0 /H 2 O systems; (2) elucidate the kinetics and mechanism of Cr VI removal; (3) study the nature of secondary mineral phases precipitated at the Fe 0 surface; and (4) find methods to enhance the efficiency of Cr VI removal. With respect to the mechanism of Cr VI removal, the large majority of articles have indicated direct (heterogeneous) reduction with Fe 0 as the main removal pathway [25,27,52,54].…”

Section: More Recent Laboratory-scale Reports (Post Elisabeth City Prb)mentioning

confidence: 99%

“…The importance of indirect reduction is obvious but the paramount goal of decontamination is removal and not simple reduction. Obviously, since iron oxide layers are excellent absorbents for negatively charged Cr VI , adsorption of Cr VI onto the oxide layer is the first step that should be taken into account when discussing Cr VI removal in Fe 0 /H 2 O systems [14,90]. Despite being adsorbed, indirect reduction of Cr VI is still likely.…”

Section: More Recent Laboratory-scale Reports (Post Elisabeth City Prb)mentioning

confidence: 99%

“…Cr III tends to be extremely insoluble (<20 µg/L) between pH 7.0 and pH 10.0, with minimum solubility at pH 8.0 of about 1 µg/L. Hence, Cr III is readily immobilized at circumneutral pH by precipitation as hydroxides, having thus a much lower mobility than Cr VI [14]. Since Cr VI readily crosses cell membranes, it is highly toxic to most living organisms [4].…”

Section: Geochemistry Of Chromiummentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 93%

Section: More Recent Laboratory-scale Reports (Post Elisabeth City Prb)mentioning

confidence: 99%

Section: More Recent Laboratory-scale Reports (Post Elisabeth City Prb)mentioning

confidence: 99%

Section: Geochemistry Of Chromiummentioning

confidence: 99%

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

Gheju¹

2018

Water

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“…Chromium exists in various oxidation states ranging from Cr(II) to Cr(VI). Among these states, Cr(III) and Cr(VI) are the most common and most stable species [1,2]. Different species of chromium originate from its industrial applications, as well as incineration facilities, cement, contaminated landfill, asbestos lining erosion, tobacco smoke, topsoil and rocks [3].…”

Section: Introductionmentioning

confidence: 99%

Interactive Relationship between Cementitious Materials and Acid Mine Drainage: Their Effects on Chromium Cr(VI) Removal

Shabalala

Basitere

2020

Minerals

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Elevated hexavalent chromium (Cr(VI)) levels in pervious concrete may undermine its successful application in water treatment. Portland cement CEM I 52.5R (CEM I), coal fly ash (FA), natural zeolite and ground granulated blast-furnace slag (GGBS) were evaluated as adsorbents for removal of Cr(VI) from acid mine drainage (AMD). Adsorption experiments were conducted at dosages of 6, 10, 30 and 60 g of adsorbent in 200 mL of AMD, while the mixing contact time was varied from 15 to 300 min. It was found that the use of CEM1 and FA adsorbents strongly increased the Cr(VI) concentration in AMD. Conversely, zeolite and GGBS removed up to 76% and 100% of Cr(VI) from AMD, respectively, upon their use at dosages of at least 10 g of the adsorbent. Freundlich isotherm was found better fitted with a high correlation coefficient (R2 = 0.998 for zeolite and 0.973 for GGBS) than to the Langmuir model (R2 = 0.965 for zeolite and 0.955 for GGBS). Adsorption and ion exchange seem to be active mechanisms for the Cr(VI) removal. These results suggest that zeolite and GGBS can be considered as partial cement replacement materials for effective reduction or removal of Cr(VI) from the treated water.

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A comprehensive review on chromium chemistry along with detection, speciation, extraction and remediation of hexavalent chromium in contemporary science and technology

Mondal,

Begum,

Nasrollahzadeh

et al. 2021

Vietnam Journal of Chemistry

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The presence of hexavalent chromium in our environment is a potential mutagenic hazard for the whole animal and plant kingdom including humans. In the last five decades numerous physico‐chemical and bio‐chemical mechanisms have been proposed for the detection of chromium speciation, extraction and remediation of the same from contaminated environmental samples. This present review is dedicated on the discussions of detection of chromium speciation in various environmental samples viz., industrial wastes, workplace particulates, plants, aquatic animals and food samples. Different physical, chemical and biological analytical methods have been presented. Mechanisms of such detection, extraction/remediation techniques are also emphasised. The aim of this article is to comprehend the contemporary advancement in this field that may be applied from lab to industry levels.

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Decontamination of Hexavalent Chromium-Polluted Waters: Significance of Metallic Iron Technology

Cited by 8 publications

References 249 publications

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

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

Interactive Relationship between Cementitious Materials and Acid Mine Drainage: Their Effects on Chromium Cr(VI) Removal

A comprehensive review on chromium chemistry along with detection, speciation, extraction and remediation of hexavalent chromium in contemporary science and technology

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