The Chemical Relation of Iron and Manganese in Sedimentary Rocks

Penrose, R. A. F.

doi:10.1086/606194

Cited by 6 publications

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“…At t > t 0 , the Fe 0 /MnO x /sand system hosts dynamic processes which might continue after Fe 0 depletion. In fact, the mixture of Fe and MnO x minerals is a very complex reactive system that has been investigated for more that a century 66 – 68 . The uniqueness of the Fe 0 /MnO x /sand system is that Fe minerals are generated in-situ and are comparatively more reactive than aged minerals like goethite or hematite.…”

Section: Methodsmentioning

confidence: 99%

“…Due to the good adsorptive affinities of Fe 2+ and Fe 3+ for sand surface, it is assumed that the deposition of Fe hydroxides at its surface (coating) will compete with Fe 2+ consumption by the reductive dissolution of MnO x until sand coating is completed. Thereafter, the “free” precipitation of iron and manganese occurs and the final products are deposits of more or less pure iron and manganese ores 66 , 71 . In other words, the investigated Fe 0 /MnO x /sand system is a ternary system only at the start of the experiment.…”

Section: Methodsmentioning

confidence: 99%

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The key role of contact time in elucidating the mechanisms of enhanced decontamination by Fe0/MnO2/sand systems

Cao¹,

Alyoussef²,

Gatcha-Bandjun

et al. 2021

Sci Rep

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Metallic iron (Fe0) has shown outstanding performances for water decontamination and its efficiency has been improved by the presence of sand (Fe0/sand) and manganese oxide (Fe0/MnOx). In this study, a ternary Fe0/MnOx/sand system is characterized for its discoloration efficiency of methylene blue (MB) in quiescent batch studies for 7, 18, 25 and 47 days. The objective was to understand the fundamental mechanisms of water treatment in Fe0/H2O systems using MB as an operational tracer of reactivity. The premise was that, in the short term, both MnO2 and sand delay MB discoloration by avoiding the availability of free iron corrosion products (FeCPs). Results clearly demonstrate no monotonous increase in MB discoloration with increasing contact time. As a rule, the extent of MB discoloration is influenced by the diffusive transport of MB from the solution to the aggregates at the bottom of the vessels (test-tubes). The presence of MnOx and sand enabled the long-term generation of iron hydroxides for MB discoloration by adsorption and co-precipitation. Results clearly reveal the complexity of the Fe0/MnOx/sand system, while establishing that both MnOx and sand improve the efficiency of Fe0/H2O systems in the long-term. This study establishes the mechanisms of the promotion of water decontamination by amending Fe0-based systems with reactive MnOx.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The key role of contact time in elucidating the mechanisms of enhanced decontamination by Fe0/MnO2/sand systems

Cao¹,

Alyoussef²,

Gatcha-Bandjun

et al. 2021

Sci Rep

View full text Add to dashboard Cite

show abstract

“…At t > t 0 , the Fe 0 /MnO x /sand system hosts dynamic processes which might continue after Fe 0 depletion. In fact, the mixture of Fe and Mn minerals is a very complex reactive system that has been investigated for more that a century [56][57][58]. The uniqueness of the Fe 0 /MnO x /sand system is that Fe minerals are generated in-situ and are comparatively more reactive than aged minerals like goethite or hematite.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the good adsorptive a nities of Fe 2 + and Fe 3 + for sand surface, it is assumed that the deposition of Fe hydroxides at it surface (coating) will compete with Fe 2 + consumption by the reductive dissolution of MnO x until sand coating is completed. Thereafter, the "free" precipitation of iron and manganese occurs and the nal products are deposits of more or less pure iron and manganese ores [56,61]. In other words, the investigated Fe 0 /MnO x /sand system is a ternary system only at the start of the experiment.…”

Section: Introductionmentioning

confidence: 99%

The Key Role of Contact Time in Elucidating the Mechanism of Enhanced Decontamination by Fe0/mno2/sand Systems

Cao

Alyoussef

Gatcha-Bandjun

et al. 2021

Preprint

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Metallic iron (Fe0) has shown outstanding performances for water decontamination and its efficiency has been improved by the presence of sand (Fe0/sand) and manganese oxide (Fe0/MnOx). In this study, a ternary Fe0/MnOx/sand system is characterized for its discoloration efficiency of methylene blue (MB) in quiescent batch studies for 7, 18, 25 and 47 d. The objective was to understand the fundamental mechanisms of water treatment in Fe0/H2O systems using MB as an operational tracer of reactivity. The premise was that, in the short term, both MnO2 and sand delay MB discoloration by avoiding the availability of free iron corrosion products (FeCPs). Results clearly demonstrate no monotonous increase in MB discoloration with increasing contact time. As a rule, the extent of MB discoloration is influenced by the diffusive transport of MB from the solution to the aggregates at the bottom of the vessels (test-tubes). The presence of MnOx and sand enabled the long-term generation of iron hydroxides for MB discoloration by adsorption and co-precipitation. Results clearly reveal the complexity of the Fe0/MnOx/sand system, while establishing that both MnOx and sand improve the efficiency of Fe0/H2O systems in the long-term. This study establishes the mechanisms of the promotion of water decontamination by amending Fe0-based systems with reactive MnOx.

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Geochemical Characterization and Controlling Factors of Chemical Composition of Spring Water in a Part of Eastern Himalaya

Vishwakarma

Sen

Singh

et al. 2018

Journal of the Geological Society of India

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This paper focuses on the suitability of spring water for drinking and irrigation purposes in a part of eastern Himalaya, south Sikkim. There are many anthropogenic and geogenic factors contributing as a source of major cations and anions in the spring water. The spring water chemistry show a variation in EC, pH, TDS, Temperature, Na+, K+, Mg2+, Ca2+, Fe2+, Pb, Mn, Cu, HCO3−, Cl−, PO43−, NO3−, F− and SO42−. Mainly two types of water quality indexing has been used, one for suitability of spring water for drinking purposes and the other for irrigation purposes. For drinking purposes, Piper diagram used for determination of water type, water quality index (WQI) for quality monitoring and saturation index for mineral dissolution in water. % Na, RSC (Residual Sodium Carbon) and SAR (sodium absorption ratio) have been used for irrigation suitability. Piper diagram shows that CaHCO3 type of water was dominant in the study area. The WQI depicted excellent category and SAR, percent sodium and RSC (Residual Sodium Carbon) depict excellent, good and permissible category for irrigation purposes. Principle component analysis (PCA) was used to determine the major influencing factor responsible for the variability in the parameters analysed of spring water.

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The Chemical Relation of Iron and Manganese in Sedimentary Rocks

Cited by 6 publications

References 0 publications

The key role of contact time in elucidating the mechanisms of enhanced decontamination by Fe0/MnO2/sand systems

The key role of contact time in elucidating the mechanisms of enhanced decontamination by Fe0/MnO2/sand systems

The Key Role of Contact Time in Elucidating the Mechanism of Enhanced Decontamination by Fe0/mno2/sand Systems

Geochemical Characterization and Controlling Factors of Chemical Composition of Spring Water in a Part of Eastern Himalaya

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