Mechanism and kinetics of cyanide ozonation in water

Zeevalkink, J.A.; Visser, D.C.; Arnoldy, P.; Boelhouwer, C.

doi:10.1016/0043-1354(80)90001-9

Cited by 34 publications

(29 citation statements)

References 14 publications

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“…But, it was limited owing to the instability of the chemical [14]. Ozonation of free cyanide or complexed cyanide is limited by low rate of ozone mass transfer into aqueous phase at high pH [15]. The most practiced method is alkaline chlorination, which has many disadvantages such as formation of toxic cyanogens chloride [16] and chloride disinfection by-products [17].…”

Section: Introductionmentioning

confidence: 99%

Reaction of Cu(CN)32− with H2O2 in water under alkaline conditions: Cyanide oxidation, Cu+/Cu2+ catalysis and H2O2 decomposition

Chen

Zhao

Liu

et al. 2014

Applied Catalysis B: Environmental

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Section: Introductionmentioning

confidence: 99%

Reaction of Cu(CN)32− with H2O2 in water under alkaline conditions: Cyanide oxidation, Cu+/Cu2+ catalysis and H2O2 decomposition

Chen

Zhao

Liu

et al. 2014

Applied Catalysis B: Environmental

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“…Several methods have been devised to meet growing needs for alternative methods for destroying cyanides: electrolytic decomposition, ozonation, electrodialysis, catalytic oxidation, reverse osmosis, ion exchange, genetic engineering application, and photocatalytic oxidation. [2][3][4][5][6][7][8] Recently, Sharma et al 9 reported that ferrate (FeO 4 2À ) is an effective iron-based oxidant for cyanide destruction. This is a ''green'' oxidant for a variety of organic and inorganic compounds such as alcohols, 10,11 amines, 11,12 hydrazines, 13 peroxides, 14 hydrocarbons, 15 thiourea, 16 and sulfonamides 17 with harmless wastes of rust, which is easily separated from desired products.…”

mentioning

confidence: 99%

Mechanism and Kinetics of Cyanide Decomposition by Ferrate

Kamachi¹,

Nakayama²,

Yoshizawa³

2008

Bulletin of the Chemical Society of Japan

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The mechanism of cyanide oxidation by ferrate in water is discussed using DFT computations in the framework of the polarizable continuum model. The reactivity of three oxidants, nonprotonated, monoprotonated, and diprotonated ferrates is evaluated. This reaction is initiated by a direct attack of an oxo group of ferrate to the carbon atom of cyanide, followed by an H-atom transfer from cyanide to another oxo group to lead to an intermediate having cyanate (NCO À ) as a ligand. The produced cyanate is oxidized by an oxo ligand of ferrate and exogenous oxygen molecule to CO 2 and NO 2 À . The initial C-O bond formation is found to be the rate-determining step in this reaction. The activation energy for the C-O bond formation is 51.9 kJ mol À1 for nonprotonated ferrate, 44.4 kJ mol À1 for monoprotonated ferrate, and 41.4 kJ mol À1 for diprotonated ferrate, which indicates that the oxidizing power of the three oxidants is in the order of nonprotonated ferrate < monoprotonated ferrate < diprotonated ferrate. The general energy profile for cyanide oxidation by ferrate is downhill toward the product direction after the C-O bond formation, so cyanide is readily converted to the final products in water. The reaction kinetics of this reaction are analyzed from the calculated energy profile and experimentally determined pK a values.Since cyanides are used to solubilize metal ions in basic solutions, cyanide compounds are involved in wastewater streams from processes such as gold refining, metal plating, and iron and steel manufacturing.1 The compounds are very toxic and must be removed from the wastewater prior to discharge. The most common method of cyanide destruction is alkaline chlorination using sodium hypochlorite at basic pH, as shown below.Unfortunately, this method has some disadvantages such as high chemical costs, formation of toxic intermediate, and chloride contamination. Several methods have been devised to meet growing needs for alternative methods for destroying cyanides: electrolytic decomposition, ozonation, electrodialysis, catalytic oxidation, reverse osmosis, ion exchange, genetic engineering application, and photocatalytic oxidation. From an X-ray analysis, ferrate was found to be tetrahedral in structure like in chromate and manganate. 21 An isotope labeling experiment of oxygen 14 and IR spectroscopy 22 demonstrated that ferrate ion remains monomeric in aqueous solution and that the four oxygen atoms of ferrate are equivalent and exchangeable with solvent water.From density functional theory (DFT) calculations, we have investigated the mechanism and energetics of alcohol oxidation 23,24 and alkane hydroxylation 25 by ferrate. These reactions are likely to be initiated by an H-atom abstraction from a C-H or O-H bond. Our calculated results demonstrated that the oxidizing power of the three active species increases in the order nonprotonated ferrate < monoprotonated ferrate < diprotonated ferrate. 24 However, diprotonated ferrate is unlikely to be a main oxidant in the reaction because the fraction of...

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“…시안이온과는 달리 전이금속과 강력한 복합체를 형 성하고 있는 시안화합물 등은 위에서 언급한 처리공정으로 그 완전분해의 한계를 가지고 있다. 따라서, 이러한 문제점 을 극복하기 위한 방법으로는 산화제를 투입한 물리-화학 적 공정 (Haag and Yao, 1992), 오존(ozone) 산화법 (Gurol and Holden, 1988;Zeevalkink et al, 1980), 광촉매 (Chang et al, 1999;Haber and Weiss, 1934;Kim and Lee, 1998;Lim et al, 2005). 기존 의 Fenton 공정은 낮은 pH 영역에서만 활성이 가능한 단점 을 가지고 있으며, 이를 보완한 modified Fenton 공정은 중 성 pH에서 촉매인 철이온의 안정성을 확보함으로서 펜톤 (Fenton) 공정의 단점을 극복하였다 (Chang et al, 2000;Watts et al, 1999;Watts and Dilly, 1996).…”

Section: Introduction 1)unclassified

Cyanide Degradation from Plating Wastewater Using Iron Oxide Nanocomposite Layer

Kim¹,

Lim²,

Park³

2014

Journal of Korean Society on Water Environment

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We synthesized the self-organized nanoporous oxide with potentiostatic anodization of iron foil. The iron oxide nanocomposite (INCs) were fabricated in 1M Na2SO4 containing 0.5wt% NaF electrolyte holding the potential at 20, 40 and 60 V for 20min, respectively. Field Emmision Scanning Electron Microscopy (FESEM) and X-ray Diffractometer (XRD) were used to evaluate the micromorphology and crystalline structure of INC film. Also, this study was performed to evaluate the fenton reaction using INC film with hydroperoxide for degradation of cyanide dissolved in water. In case of INC-40V in the presence of H2O2 3%, the first-order rate constant was found to be 1.7 × 10 -2 min -1 , and indicated to be 1.2 × 10 -2 min -1 on commercial hematite powder. This result is shown to be good performance enough to replace the powder type for treatment of wastewater.

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Mechanism and kinetics of cyanide ozonation in water

Cited by 34 publications

References 14 publications

Reaction of Cu(CN)32− with H2O2 in water under alkaline conditions: Cyanide oxidation, Cu+/Cu2+ catalysis and H2O2 decomposition

Reaction of Cu(CN)32− with H2O2 in water under alkaline conditions: Cyanide oxidation, Cu+/Cu2+ catalysis and H2O2 decomposition

Mechanism and Kinetics of Cyanide Decomposition by Ferrate

Cyanide Degradation from Plating Wastewater Using Iron Oxide Nanocomposite Layer

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