Towards in situ electro-generation of ferrate for drinking water treatment: A comparison of three low-cost sacrificial iron electrodes

Díaz, Miguel; Doederer, Katrin; Keller, Jürg; Cataldo, M.; Donose, Bogdan C.; Ali, Yahia; Ledezma, Pablo

doi:10.1016/j.jelechem.2020.114897

Cited by 12 publications

(20 citation statements)

References 45 publications

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“…In their work, vibration frequencies were also compiled but there were no experimental data to compare with. They continued by saying that only a "highly correlated ab initio multiconfiguration approach gave sound support for the lowest isomer being a ferryl peroxide, 1 [104]". (Note that the preference of the Fe VI (d 2 ) 1 A 1 singlet state complex is owed to the reduced C 2v symmetry.)…”

Section: History Of Analysis Of Ferrate (Vi) By Vibration Spectroscopymentioning

confidence: 99%

“…Recently, innovative methods of generation of ferrate(VI) and its applications have been identified. Diaz et al [ 1 ] produced ferrate(VI) in highly alkaline solutions (NaOH or KOH at 10 mol dm −3 , the theoretical pH at this concentration is 16.15 according to Licht [ 2 ]) by electro-oxidation of several inexpensive iron-containing materials (as electrodes) and found that Grey Cast Iron, the alloy composed of Fe-C(graphite)-Si, is the best material. McBeath et al [ 3 ] demonstrated a new concept of the generation of ferrate(VI), in situ, by electrochemical oxidation of Fe 2+ ions already present in wastewaters at near-neutral pH, the Fe(VI) ions produced in turn oxidizing other co-existing contaminants.…”

Section: Introductionmentioning

confidence: 99%

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On the Origins of Some Spectroscopic Properties of “Purple Iron” (the Tetraoxoferrate(VI) Ion) and Its Pourbaix Safe-Space

et al. 2021

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In this work, the authors attempt to interpret the visible, infrared and Raman spectra of ferrate(VI) by means of theoretical physical-inorganic chemistry and historical highlights in this field of interest. In addition, the sacrificial decomposition of ferrate(VI) during water treatment will also be discussed together with a brief mention of how Rayleigh scattering caused by the decomposition of FeVIO42− may render absorbance readings erroneous. This work is not a compendium of all the instrumental methods of analysis which have been deployed to identify ferrate(VI) or to study its plethora of reactions, but mention will be made of the relevant techniques (e.g., Mössbauer Spectroscopy amongst others) which support and advance this overall discourse at appropriate junctures, without undue elaboration on the foundational physics of these techniques.

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Section: History Of Analysis Of Ferrate (Vi) By Vibration Spectroscopymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the Origins of Some Spectroscopic Properties of “Purple Iron” (the Tetraoxoferrate(VI) Ion) and Its Pourbaix Safe-Space

et al. 2021

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“…However, the oxidant may be generated in situ by electrochemical processes (Jiang et al, 2009). According to Diaz et al (2021), the highest efficiency of ferrate(VI) generation was achieved using gray cast iron (GCI), in presence of 10 mol/L NaOH. The production rate was 0.979 mol FeO 4 m −3 day −1 (including time for cleaning in between cycles) at the energy consumption 8 kWh kg −1 .…”

Section: C1mentioning

confidence: 99%

“…It does not contained toxic metal like chromium. Comparatively, production of chlorine via electrolysis of NaCl has a typical energy consumption of 2.2-2.6 kWh kg −1 Cl 2 whereas electrogeneration of ozone (depends on solution and electrode material composition) has energy consumption in the range from ~ 18 to 175 kWh kg −1 O 3 (Diaz et al (2021). However, Cl 2 and ozone have lower oxidation potential and lower reactivity than potassium ferrate(VI).…”

Section: C1mentioning

confidence: 99%

Influence of Elevated Temperature and Pressure on Treatment of Landfill Leachate by Potassium Ferrate(VI)

Thomas

Drzewicz

Więckol‐Ryk

et al. 2021

Water Air Soil Pollut

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The significant problem is the treatment of landfill leachate characterized by high chemical oxygen demand (COD) and total organic carbon (TOC) and presence of biodegradation inhibitors such as heavy metals and oily substances. For the case of landfill leachate (pH 7.9, color 1550 mg Pt/L, COD 1880 mg O2/L, TOC 620 mg/L, total nitrogen (TN) 220 mg/L, total phosphorus (TP) 6 mg/L and heavy metals), the effect of elevated pressure and temperature on the decrease COD value by potassium ferrate(VI) (K2FeO4) was investigated. Taguchi method (TM) was employed for optimizing the treatment process parameters (repetition, pH, K2FeO4 concentration, time, temperature, and pressure). Maximizing the criterion function of signal-to-noise (S/N), the optimal parameters were determined: pH 3.5, K2FeO4 2.0 g/L, time 45 min, temperature 30 °C, and pressure of 1 MPa. At optimal conditions, a decrease of color, COD, TOC, and TP was above 91%. Additionally, the decrease of TN was 48.2%. Comparatively, at atmospheric pressure (0.1013 MPa) and at 19 °C, the decrease of color, COD, TOC, TP, and TN was 99.9%, 83.0%, 79.0%, 19.1%, and 100%, respectively. Addition of potassium ferrate(VI) may improve organic compound removal and decreases energy consumption in subcritical water oxidation. Graphical abstract

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“…[ 36,45,46 ] Moreover, conventional chemical synthesis of ferrate requires hypochlorite, which diminishes the advantage of using a green oxidizer. [ 36–40 ]…”

Section: Introductionmentioning

confidence: 99%

Degradation of Lignosulfonate to Vanillic Acid Using Ferrate

Klein

Kupec

Stöckl

et al. 2022

Advanced Sustainable Systems

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high technical interest as renewable and biobased feedstock [7] due to their aromatic backbone and high availability. [8][9][10][11] Consequently, the targeted degradation of the respective lignin fractions to value-added products is highly desired. [12,13] The difficulty of this process lies in the different functionalization and the structure of the polyphenolic backbone, which depends on many factors such as pulping process, harvesting time, and type of tree. [10,14] Therefore, the industry uses only small fractions for further production, while the majority is incinerated to recover energy costs. [4,9] Lignin, as a renewable feedstock, offers a promising alternative to petroleum refining and shows tremendous potential for bio-based products such as surfactants and fine chemicals. [5,13,15] Nevertheless, selective degradation is challenging, and several studies focused on this complex topic to degrade lignin into value-added products such as aromatic intermediates. [8,[16][17][18] Lignin degradation shows a broad and diverse spectrum of products, such as aldehydes, [19][20][21]22] alcohols, [21] arenes, [18,23,24] quinones, [25] and carboxylic acids, [16,26,27] obtained in previous research. Different metal-based catalysts were studied to improve degradation and increase selectivity including noble metals like ruthenium, palladium, and platinum. [28] The disadvantages of these processes are the very high costs and limited availability of the metals, which might also cause uncontrolled over-hydrogenation, decreasing the yield of the phenolic products. Another approach is using ionic liquids as solvents in combination with catalysts or oxidizers. [29] However, the high costs for ionic liquids restrict their application for industrial operations. Additionally, the separation process is complex due to interactions with aromatic moieties of residual lignin.Promising electrochemical pathways are reported to yield aldehydes, [3,21,30] carboxylic acids, [27,31] and other phenolic products in good yields. [19,21,27,30] These methods are cost-effective and environmentally friendly. [32] Also, a well-known alternative is the use of oxidizers for lignin degradation. [3,20,23] However, only a few oxidizers, such as periodate, [3] nitrobenzene, [33,34] or hydrogen peroxide, [35] have high availability, and are safe in handling. Moreover, lignin conversion is not limited to the electrode surface since the respective oxidizers are dissolved. The monomer yields out of lignin using oxidizers vary significantly due to different wood types and experimental conditions. In a previous report, we showed that platform oxidizers, such as periodate, are highly beneficial for lignin degradation. This method significantly improves the vanillin yield (8.9 wt%) or selectively produces 5-iodovanillin using different workup conditions. [3] A new method is presented using electrochemically generated ferrate to degrade the technically relevant bio-based side-stream products, lignin and lignosulfonate. An exclusive degradation to vanillic ac...

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Towards in situ electro-generation of ferrate for drinking water treatment: A comparison of three low-cost sacrificial iron electrodes

Cited by 12 publications

References 45 publications

On the Origins of Some Spectroscopic Properties of “Purple Iron” (the Tetraoxoferrate(VI) Ion) and Its Pourbaix Safe-Space

On the Origins of Some Spectroscopic Properties of “Purple Iron” (the Tetraoxoferrate(VI) Ion) and Its Pourbaix Safe-Space

Influence of Elevated Temperature and Pressure on Treatment of Landfill Leachate by Potassium Ferrate(VI)

Degradation of Lignosulfonate to Vanillic Acid Using Ferrate

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