MDPI - Publisher of Open Access Journals

19 pages, 4720 KB

Open AccessArticle

Enhanced Decolorization and Mineralization of Acid Violet 19 Dye by Potassium Ferrate (VI)

by Bimo Tri Goutomo, Seong Yeop Han, Dian Majid and Il-Kyu Kim

AppliedChem 2026, 6(1), 9; https://doi.org/10.3390/appliedchem6010009 - 2 Feb 2026

Cited by 1 | Viewed by 1263

Acid violet 19 (AV19) dye is used in many fields, including photographic film, inks, leather, and textiles. Potassium ferrate (VI) (Fe(VI)) represents a novel oxidant, notable for its strong oxidative capabilities, stability, and environmental sustainability. This research investigates the decolorization and mineralization of AV19 through the application of Fe(VI), with a particular emphasis on essential parameters, including pH, molar ratios, and temperature variations. The study ascertained that the optimal conditions for AV19 oxidation are a pH of 7.0, a molar ratio of AV19: Fe(VI) of 1:5, and a temperature of 45 °C with a reaction time of 12 min. The decolorization efficiency achieved was approximately 98%, and the mineralization was 31%. The degradation process yielded intermediates, such as sulfonic acid derivatives, benzoic acid, benzene, and cyclohexane compounds, which were further oxidized into acetic acid, carbon dioxide, and water. Comprehensive computational toxicity evaluations confirmed that both the intermediates and the final products are non-toxic. Full article

(This article belongs to the Special Issue Analytical Chemistry: Fundamentals, Current and Future Applications)

► Show Figures

Figure 1

13 pages, 2684 KB

Open AccessArticle

Comparative Study of Ferrate, Persulfate, and Percarbonate as Oxidants in Plasma-Based Dye Remediation: Assessing Their Potential for Process Enhancement

by Amina Ouzar, Bimo Tri Goutomo, Kyung-Min Lee and Il-Kyu Kim

Appl. Sci. 2025, 15(24), 13158; https://doi.org/10.3390/app152413158 - 15 Dec 2025

Viewed by 635

Abstract

In this study, three benign oxidants, potassium ferrate (Fe(VI)), sodium persulfate (PS), and sodium percarbonate (SPC), were combined with nonthermal plasma (NTP) to enhance the degradation of Malachite Green (MG) and Metanil Yellow (MY). Experimental factors, including dye concentration, oxidant dose, and treatment time, were optimized using Response Surface Methodology (RSM). The hybrid systems achieved markedly improved decolorization rates, with maximum efficiencies exceeding 99% within 30 min, compared to 96% for NTP alone. Kinetic analysis confirmed significantly higher rate constants for NTP-assisted oxidants, particularly NTP + Fe (VI) (k_obs = 0.127 min⁻¹), followed by NTP + PS (0.114 min⁻¹) and NTP + SPC (0.098 min⁻¹). Enhanced mineralization, together with stable pH and controlled conductivity variations, further substantiated the efficient breakdown of the dye molecules. Phytotoxicity assays demonstrated that untreated dyes severely inhibited germination. In contrast, effluents treated with NTP + PS and NTP + Fe (VI) restored germination and root growth to levels comparable to the deionized water (DIW) control, indicating substantial toxicity reduction. These results confirm that NTP-oxidants significantly improve oxidation performance, accelerate reaction kinetics, and yield environmentally safe effluents suitable for practical wastewater remediation. Full article

► Show Figures

Figure 1

19 pages, 2979 KB

Open AccessArticle

Quantitative Analysis of Ferrate(VI) and Its Degradation Products in Electrochemically Produced Potassium Ferrate for Waste Water Treatment

by Zoltán Homonnay, Sándor Stichleutner, Ernő Kuzmann, Miklós Kuti, Győző G. Láng, Kende Attila Béres, László Trif, Dániel J. Nagy, Gyula Záray and József Lendvai

Appl. Sci. 2024, 14(19), 9144; https://doi.org/10.3390/app14199144 - 9 Oct 2024

Cited by 1 | Viewed by 3296

Abstract

Potassium ferrate(VI) (K₂FeO₄) as a particularly strong oxidant represents an effective and environmentally friendly waste water treatment material. When produced by anodic oxidation in highly alkaline aqueous solution, the K₂FeO₄ product is separated and sealed in inert plastic bags with the retention of some liquid phase with high pH. This method proved to be excellent for long-term storage at moderately low temperature (5 °C) for industrial applications. It is still imperative to check the ferrate(VI) content of the product whenever it is to be used. Fe-57 Mössbauer spectroscopy is an excellent tool for checking the ratio of ferrate(VI) to the degradation product iron(III) in a sample. For this purpose, normally the spectral areas of the corresponding subspectra are considered; however, this approximation neglects the possible differences in the corresponding Mössbauer–Lamb factors. In this work, we have successfully determined the Mössbauer–Lamb factors for the ferrate(VI) and for the most common iron(III) degradation products observed. We have found superparamagnetic behavior and low-temperature phase transformation for another iron(III) degradation product that made the determination of the Mössbauer–Lamb factors impossible in that case. The identities of a total of three different iron(III) degradation products have been confirmed. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Metal Oxide Nanoparticles)

► Show Figures

Figure 1

15 pages, 2878 KB

Open AccessArticle

Enhanced Removal of Doxycycline by Simultaneous Potassium Ferrate(VI) and Montmorillonite: Reaction Mechanism and Synergistic Effect

by Hangli Zhang, Shujuan Wang, Ji Shu and Hongyu Wang

Water 2023, 15(9), 1758; https://doi.org/10.3390/w15091758 - 3 May 2023

Cited by 1 | Viewed by 3035

Abstract

Doxycycline (DOX), a typical antibiotic, is harmful to aquatic ecosystems and human health. This study presents DOX removal by potassium ferrate (Fe(VI)) and montmorillonite and investigates the effect of Fe(VI) dosage, reaction time, initial pH value, montmorillonite dosage, adsorption pH, time and temperature on DOX removal. The results show that DOX removal increases when increasing the Fe(VI) dosage, with the optimal condition for DOX removal (~97%) by Fe(VI) observed under a molar ratio ([Fe(VI)]:[DOX]) of 30:1 at pH 7. The reaction of DOX with Fe(VI) obeyed second-order kinetics with a rate constant of 10.7 ± 0.45 M⁻¹ s⁻¹ at pH 7. The limited promotion (~4%) of DOX adsorption by montmorillonite was observed when the temperature increased and the pH decreased. Moreover, the synergetic effect of Fe(VI) and montmorillonite on DOX removal was obtained when comparing the various types of dosing sequences (Fe(VI) oxidation first and then adsorption; adsorption first and then Fe(VI) oxidation; simultaneous oxidation and adsorption). The best synergistic effect of DOX removal (97%) was observed under the simultaneous addition of Fe(VI) and montmorillonite, maintaining the Fe(VI) dosage (from 30:1 to 5:1). Five intermediates were detected during DOX degradation, and a plausible DOX degradation pathway was proposed. Full article

(This article belongs to the Topic Advanced Oxidation Process: Applications and Prospects)

► Show Figures

Figure 1

16 pages, 2400 KB

Open AccessArticle

Potassium Ferrate (VI) as the Multifunctional Agent in the Treatment of Landfill Leachate

by Maciej Thomas, Violetta Kozik, Krzysztof Barbusiński, Aleksander Sochanik, Josef Jampilek and Andrzej Bąk

Materials 2020, 13(21), 5017; https://doi.org/10.3390/ma13215017 - 6 Nov 2020

Cited by 15 | Viewed by 3554

Abstract

Possible use of potassium ferrate (VI) (K₂FeO₄) for the treatment of landfill leachate (pH = 8.9, Chemical Oxygen Demand (COD) 770 mg O₂/L, Total Organic Carbon (TOC) 230 mg/L, Total Nitrogen (Total N) 120 mg/L, Total Phosphorus (Total P) 12 mg/L, Total Coli Count (TCC) 6.8 log CFU/mL (Colony-Forming Unit/mL), Most Probable Number (MPN) of fecal enterococci 4.0 log/100 mL, Total Proteolytic Count (TPC) 4.4 log CFU/mL) to remove COD was investigated. Central Composite Design (CCD) and Response Surface Methodology (RSM) were applied for modelling and optimizing the purification process. Conformity of experimental and predicted data (R² = 0.8477, R_adj² = 0.7462) were verified using Analysis of Variance (ANOVA). Application of K₂FeO₄ using CCD/RSM allowed to decrease COD, TOC, Total N, Total P, TCC, MPN of fecal enterococci and TPC by 76.2%, 82.6%, 68.3%, 91.6%, 99.0%, 95.8% and 99.3%, respectively, by using K₂FeO₄ 0.390 g/L, at pH = 2.3 within 25 min. Application of equivalent amount of iron (as FeSO₄ × 7H₂O and FeCl₃ × 6H₂O) under the same conditions allowed to diminish COD, TOC, Total N, Total P, TCC, MPN of fecal enterococci and TPC only by 38.1%, 37.0%, 20.8%, 95.8%, 94.4%, 58.2%, 90.8% and 41.6%, 45.7%, 29.2%, 95.8%, 92.1%, 58.2%, 90.0%, respectively. Thus, K₂FeO₄ could be applied as an environmentally friendly reagent for landfill leachate treatment. Full article

(This article belongs to the Special Issue Heterogeneous Catalysts for Energy and Environmental Applications)

► Show Figures

Graphical abstract

18 pages, 678 KB

Open AccessArticle

Preparation of Potassium Ferrate from Spent Steel Pickling Liquid

by Yu-Ling Wei, Yu-Shun Wang and Chia-Hung Liu

Metals 2015, 5(4), 1770-1787; https://doi.org/10.3390/met5041770 - 24 Sep 2015

Cited by 34 | Viewed by 10320

Abstract

Potassium ferrate (K₂FeO₄) is a multi-functional green reagent for water treatment with considerable combined effectiveness in oxidization, disinfection, coagulation, sterilization, adsorption, and deodorization, producing environment friendly Fe(III) end-products during the reactions. This study uses a simple method to lower Fe(VI) preparation cost by recycling iron from a spent steel pickling liquid as an iron source for preparing potassium ferrate with a wet oxidation method. The recycled iron is in powder form of ferrous (93%) and ferric chlorides (7%), as determined by X-ray Absorption Near Edge Spectrum (XANES) simulation. The synthesis method involves three steps, namely, oxidation of ferrous/ferric ions to form ferrate with NaOCl under alkaline conditions, substitution of sodium with potassium to form potassium ferrate, and continuously washing impurities with various organic solvents off the in-house ferrate. Characterization of the in-house product with various instruments, such as scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis), X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS), proves that product quality and purity are comparative to a commercialized one. Methylene blue (MB) de-colorization tests with in-house potassium ferrate shows that, within 30 min, almost all MB molecules are de-colorized at a Fe/carbon mole ratio of 2/1. Full article

(This article belongs to the Special Issue Hydrometallurgy)

► Show Figures

Graphical abstract

Search Results (6)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (6)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI