• Environmental Engineering Research
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• 제20권1호
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• pp.89-97
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• 2015

Remediation of wastewater contaminated with metal(II)-complexed species (Cu(II)-NTA (NTA: nitrilotriacetic acid), Cu(II)-EDTA (EDTA: ethylenediamine tetraacetic acid) and Cd(II)-EDTA is attempted using the potential applicability of ferrate(VI). Kinetics of pollutant degradation is obtained with the removal of ferrate(VI) studied at wide range of pH (8.0-10.0) and the concentration of metal(II)-complexed species (0.3 to 15.0 mmol/L) employing a constant dose of ferrate(VI) i.e., 1.0 mmol/L. Pseudo-first-order and pseudo-second-order rate constants were obtained in the reduction of ferrate(VI) which was then employed to obtain the overall rate constants of the pollutant degradation. The mineralization of NTA and EDTA was obtained with the change in TOC (total organic carbon) values collected by the ferrate(VI) treated pollutant samples. Decrease in pH and molar pollutant concentrations was greatly favored the percent mineralization of NTA or EDTA by the ferrate(VI) treatment. The treated pollutant samples were filtered and subjected for AAS (atomic absorption spectrophotometric) analysis to assess the simultaneous removal of copper and cadmium from aqueous solutions at the studied pH as well at the elevated pH 12.0. Results show that an enhanced removal of cadmium or copper was achieved at pH 12.0. Overall, ferrate(VI) possesses multifunctional application in wastewater treatment as it oxidizes the degradable impurities and removes metallic impurities by coagulation process.

• 공업화학
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• 제34권3호
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• pp.318-325
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• 2023

The detection of antibiotics in treated wastewater is a global concern as it enters water bodies and causes the development of antibiotic resistance genes in humans and marine life. The study specifically aims to explore the potential of ferrate (VI) in eliminating tetracycline (TCL). The degradation of TCL is optimized with parametric studies, viz., the effect of pH and concentration, which provide insights into TCL elimination. The increase in pH (from 7.0 to 10.0) favors the percentage removal of TCL; however, the increase in TCL concentrations from 0.02 to 0.3 mmol/L caused a decrease in percentage TCL removal from 97.4 to 29.1%, respectively, at pH 10.0. The time-dependent elimination of TCL using ferrate (VI) followed pseudosecond-order rate kinetics, and an apparent rate constant (kapp) was found at 1978.8 L² /mol² /min. Coexisting ions, i.e., NaNO₃, Na₂HPO₄, NaCl, and oxalic acid, negligibly affect the oxidation of TCL by ferrate (VI). However, EDTA and glycine significantly inhibited the elimination of TCL using ferrate (VI). The mineralization of TCL using ferrate (VI) was favored at higher pH, and it increased from 18.57 to 32.52% when the solution pH increased from pH 7.0 to 10.0. Additionally, the real water samples containing a relatively high level of inorganic carbon spiked with TCL revealed that ferrate (VI) performance in the removal of TCL was unaffected, which further inferred the potential of ferrate (VI) in real implications.

• Environmental Engineering Research
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• 제23권2호
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• pp.129-135
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• 2018

The aim of this study is to assess the applicability of ferrate(VI) in the efficient treatment of aqueous waste contaminated with potassium hydrogen phthalate (KHP) which is known to be a potent endocrine disrupting chemicals. Simulated batch reactor operations were conducted at a wide range of pH (7.0 to 12.0) and molar ratios of KHP to ferrate(VI). Kinetic studies were performed in the degradation process and overall rate constant was found to be 83.40 L/mol/min at pH 8.0. The stoichiometry of ferrate(VI) and KHP was found to be 1:1. Further, lower pH values and higher KHP concentrations were favoured greatly the degradation of KHP by ferrate(VI). Total organic carbon analysis showed that partial mineralization of KHP was achieved. The presence of several background electrolytes were studied in the degradation of KHP by ferrate(VI).

• 공업화학
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• 제32권3호
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• pp.340-347
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• 2021

The aim of this research is to assess the use of high purity potassium ferrate (VI) for the efficient removal of sulfamethoxazole (SMX), one of the potential micro-pollutant found in aqueous waste. In addition, various parametric studies have enabled us to deduce the mechanism in the degradation process. The pH and concentration of sulfamethoxazole enable the degradation of pollutants. Moreover, the time-dependent degradation nature of sulfamethoxazole showed that the degradation of ferrate (VI) in presence of sulfamethoxazole followed the pseudo-second order kinetics and the value of rate constant increased with an increase in the SMX concentration. The stoichiometry of SMX and ferrate (VI) was found to be 2 : 1 and the overall rate constant was estimated to be 4559 L²/mmol²/min. On the other hand, the increase in pH from 8.0 to 5.0 had catalyzed the degradation of SMX. Similarly, a significant percentage in mineralization of SMX increased with a decrease in pH and concentration. The presence of co-existing ions and SMS spiked real water samples was extensively analyzed in the removal of SMX using ferrate (VI) to simulate studies on real matrix implication of ferrate (VI) technology.

• 상하수도학회지
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• 제25권1호
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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).

• 상하수도학회지
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• 제26권1호
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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.

• 상하수도학회지
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• 제29권1호
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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.

• 상하수도학회지
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• 제36권3호
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• pp.167-175
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• 2022

수용액에서 EBT의 분해는 pH, Ferrate (VI) 투입량, 초기 농도, 수용액 온도 등 다양한 변수의 조건에서 연구되었다. 최대 분해 효율은 pH 7.0에서 95.42%가 달성되었으며, 이 실험 조건에서 얻은 kapp 값은 872.87 M^-1s^-1 이었다. EBT 분해율은 Ferrate (VI)의 투입량이 증가함에 따라 증가하였으며 EBT 초기 농도가 감소함에 따라 EBT 분해의 초기 속도 상수가 증가하였다. 또한 EBT의 분해율은 온도가 10℃에서 45℃에 도달할 때까지 수용액의 온도에 따라 증가하였으며 이 실험조건에서 활성화 에너지 값은 EBT 분해에 대해 11.9 kJ/mol의 값이 도출되었다. 따라서 분해 실험의 결과는 Ferrate (VI)가 수용액상에서 EBT를 효과적으로 분해시킬 수 있음을 보여주고 있다.

• 상하수도학회지
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• 제34권1호
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• pp.61-73
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• 2020

Tetracycline is one of the most commonly used antibiotics in domestic and foreign livestock industries to suppress the growth of pathogens. Tetracycline has been reported as a non-biodegradable compound. Therefore it has been not completely removed in the sewage treatment process. In this study, tetracycline was degraded using liquid ferrate (VI). Based on these experiments, the optimal water condition (pH and water temperature) were selected, appropriate liquid ferrate (VI) dosage was calculated, and finally the degradation pathway was estimated with the intermediate products detected by LC/MS/MS. All degradation experiments were completed within 30 seconds and the optimal condition was obtained in basic condition (pH 10) at room temperature (20℃). And the appropriate molar ratio between tetracycline and liquid ferrate (VI) was 12.5:1. Finally, 12 intermediate products were detected with LC/MS/MS and the degradation pathways and the degradation pathways and proposed the degradation pathways.

• 대한환경공학회지
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• 제37권12호
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• pp.705-711
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• 2015

습식산화법으로 합성한 Ferrate(VI)를 적용하여 2,6-Dichlorophenol의 분해 연구를 하였다. 최적의 분해 조건을 찾기 위해 영향인자로 pH(산성, 염기성, 중성), DCP의 초기 농도, ferrate 주입 농도, 수용액의 온도를 두어 실험하였다. Ferrate(VI)는 강력한 산화력과 선택성이 있으며, 무해한 최종산물인 Fe(III)을 만들어 유용한 성질을 가지고 있다. Ferrate 이온은 산성과 중성 조건에서 재빠르게 Fe(III)으로 환원한다. 본 실험 결과로 DCP의 분해율은 산성과 염기성 조건보다 중성 조건에서 좋은 것으로 나타났다. ferrate 주입 농도와 DCP의 초기 농도에 따라 영향을 강하게 받는다. ferrate의 주입 농도가 증가할수록 또한 DCP의 초기 농도가 감소할수록 DCP의 분해율이 좋게 나타났다. 수용액의 온도는 10, 25, 35, $50^{\circ}C$에서 실험을 진행하였다. 최적의 조건은 $25^{\circ}C$로 나타났으며, $25^{\circ}C$에서 $50^{\circ}C$까지의 범위에서는 증가할수록 효율이 감소하는 것으로 나타났다. DCP의 중간생성물 연구는 GC/MS를 통해 실험하였다.