• Journal of Korean Society of Water and Wastewater
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• v.38 no.1
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• pp.17-27
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• 2024

This paper aims to study the degradation process for refractory azo dye namely Reactive Black 5(RB5) by potassium ferrate(VI) synthesized using the wet oxidation method. The process of degradation of azo dyes by Ferrate was studied with several parameters such as pH, different Ferrate(VI) dosage, different azo dye initial concentration, and temperature. A second-order reaction was observed in all degradation processes for RB5 having the highest degradation efficiency. The highest k_app value of RB5 degradation was 190.49 M^-1s^-1. In the pH experiments, the neutral condition has been identified as the optimum condition for the degradation of RB5 with 63.2% of dye removal. The efficiency of degradation also depends on the amount of ferrate(VI) available in the reactor. Degradation efficiency increased with an increase in Potassium Ferrate(VI) dosage or a decrease of RB5 initial concentration. The temperature has been reported as one of the most important parameters. From the results, increasing the temperature(up to 45℃) will increase the degradation efficiency of azo dye by Ferrate(VI) and if the temperature exceeds 45℃, the degradation efficiency will be decreased.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.6
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• pp.685-692
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• 2015

The concern over the risk of environmental exposure to brominated phenols has been increased and has led the researchers to focus their attention on the study of bromophenol treatment. In this study, the effects of pH and ferrate(VI) dose on the degradation of 2-bromophenol were investigated. The results indicated that the oxidation of 2-bromophenol by liquid ferrate(VI) was found to be highly sensitive to the pH condition. Furthermore, the highest removal efficiency was observed at the neutral condition with the removal efficiency of 94.2%. In addition, experimental results showed that 2-bromophenol removal efficiency increased with increasing of ferrate dosage. Ferrate(VI) dose of 0.23 mM was sufficient to remove most of the 2-bromophenol with the efficiency of 99.73% and kapp value of $2982M^{-1}s^{-1}$. Seven compounds were identified as the intermediate products by the GC/MS analysis.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.3
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• pp.167-175
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• 2022

The degradation of EBT (Eriochrome Black T) in an aqueous solution was investigated at various values of pH, Ferrate (VI) dosage, initial concentration, aqueous solution temperature. The maximum degradation efficiency was 95.42% at pH 7 and in that experimental condition, the kapp value was 872.87 M-1s-1. The degradation efficiency was proportional to the dosage of Ferrate (VI). Also, the initial rate constant of EBT degradation increased with decreasing of the EBT initial concentration. In addition, the degradation rate of EBT was increased from 74.04% to 95.42% when the temperature in the aqueous solution was increased from 10℃ to 45℃. The activation energy value was 11.9 kJ/mol for EBT degradation. Overall, the results of the degradation experiment showed that Ferrate (VI) could effectively oxidize the EBT in the aqueous phase.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.3
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• pp.453-461
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• 2012

The degradation characteristics of TCE by Ferrate(VI) oxidation have been studied. Ferrate(VI) were prepared by electrochemical method. The degradation efficiency of TCE in aqueous solution was investigated at various pH values, Ferrate(VI) doses and aqueous solution temperature values. GC-ECD was used to analyze TCE. TCE was degraded rapidly by ferrate(VI) in aqueous solution, Also, the experimental results showed that TCE removal efficiency increased with the increase of Ferrate(VI) doses. The effect of pH was investigated and the maximum degradation efficiency was obtained at pH 7. And intermediate products were identified by GC-MS techniques. Ethyl Chloride, Dichloroethylene, Chloroform, 1,1-dichloropropene, Trichloroacetic acid and Trichloroethane were identified as a reaction intermediate, and $Cl^-$ was identified as an end product.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.643-649
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• 2011

Degradation of benzothiophene(BT) in the aqueous phase by potassium ferrate(VI) was investigated. Potassium ferrate(VI) was prepared by the wet oxidation method. The degradation efficiency of BT was measured at various values of pH, ferrate(VI) dosage and initial concentration of BT. BT was degraded rapidly within 30 seconds by ferrate(VI). While the highest degradation efficiency was achieved at pH 5, the lowest degradation efficiency was achieved at pH 9. Also, the initial rate constant of BT increased with decreasing of the BT initial concentration. In addition, the intermediate analysis for the reaction of BT and ferrate(VI) has been conducted using GC-MS. Benzene, styrene, benzaldehyde, formaldehyde, benzoic acid, formic acid, and acetic acid were identified as reaction intermediates, and ${SO_4}^{2-}$ was identified as an end product.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.1
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• pp.63-74
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• 2011

The degradation characteristics of 2-chlorophenol(2-CP) by Ferrate(VI) were studied. The degradation efficiency of 2-CP in aqueous solution was investigated at various values of pH, Fe(VI) dosage, initial concentration and aqueous solution temperature. The maximum degradation efficiencies of 2-CP were obtained at pH 7.0 and aqueous solution temperature of 25$^{\circ}C$. The degradation efficiency was proportional to dosage of Fe(VI). Also, the initial rate constant of 2-CP degradation increased with decreasing of the 2-CP initial concentration. In addition, the degradation pathway study for 2-CP was conducted with GC-MS analysis. Acetic acid, formic acid, benzaldehyde and benzoic acid were identified as reaction intermediates of the 2-CP degradation by Ferrate(VI).

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.37-46
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• 2012

The degradation characteristics of TCE by Ferrate(VI) oxidation have been studied. The degradation efficiency of TCE in aqueous solution was investigated at various pH values, Ferrate(VI) doses, initial concentrations of TCE and aqueous solution temperature values. GC-ECD was used to analyze TCE. The optimum conditions of TCE degradation were obtained pH 7.0 and $25^{\circ}C$ in aqueous solution. Also, the experimental results showed that TCE removal efficiency increased with the decrease of initial concentration of TCE. And intermediate products were identified by GC-MS techniques. Ethyl Chloride, Chloroform, Ethylene, 1,2-dichloroethane and 1,1,2-trichloroethane were identified as a reaction intermediate, and $Cl^-$ was identified as an end product.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.1
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• pp.39-46
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• 2015

The degradation characteristics of perchloroethylene by ferrate(VI) oxidation have been studied. The degradation efficiency of perchloroethylene in aqueous solution was investigated at various values of ferrate(VI) dosage, pH, initial concentration of perchloroethylene and aqueous solution temperature. GC-ECD has been used to analyze the changes of perchloroethylene concentration. The optimum conditions of perchloroethylene degradation were obtained at pH 7.0 and $25^{\circ}C$ of aqueous solution temperature. Also, the experimental results showed that perchloroethylene removal efficiency increased with the decrease of initial concentration of perchloroethylene. Lastly intermediate products were identified by GC-MS techniques. Trichloroethylene and chloroform were identified as reaction intermediates.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.2
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• pp.123-130
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• 2018

This paper provided the information related to the removal of 2,4,6-tribromophenol using in-situ and stable liquid ferrates(VI). This research's goal was to observe the differences of oxidation power between in-situ liquid ferrate(VI) and stable liquid ferrate(VI). The in-situ liquid ferrate(VI) ($FeO_4{^{2-}}$) has been successfully produced with the concentration 42,000 ppm (Fe) after 11 minutes of reaction time. The stable liquid ferrate(VI) was also successfully produced following the modification method by Sharma with the produced concentrations 7,000 ppm. The stable liquid ferrate(VI) was stable for 44 days and slightly decreased afterwards. This research has been carried out using 2,4,6-tribromophenol as the representative compound. Both of ferrates(VI) have the highest oxidation capability at the neutral condition. Furthermore, the stable liquid ferrate(VI) has higher oxidation power than the in-situ liquid ferrate(VI).

• Journal of Korean Society of Water and Wastewater
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• v.35 no.1
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• pp.27-37
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• 2021

Tetracycline is one of the most commonly used as antibiotics for the livestock industry and it is still widely used nowadays. Tetracycline and its metabolites are excreted with excrement, which is difficult to completely removed with conventional sewage treatment, therefore it is apprehended that the tetracycline-resistant bacteria occurs. In this study, the oxidant named ferrate(VI) was used to degrade the tetracycline and investigate the reaction between ferrate(VI) and tetracycline under various aqueous conditions. The highest degradation efficiency of tetracycline occurred in basic condition (pH 10.1 ± 0.1) because of the pKa values of tetracycline and ferrate(VI). The results also showed the effect of water temperature on the degradation of tetracycline was not significant. In addition, the dosage of ferrate(VI) was higher, the degradation of tetracycline and the self-degradation of ferrate(VI) also higher, finally the efficiency of ferrate(VI) was lower. The results said that the various mechanisms effects the reaction of ferrate(VI) oxidation, it required the consideration of the characteristics of the target compound for optimal degradation efficiency. Additionally, intermediate products were detected with LC/MS/MS and three degradation pathways were proposed.