Investigation of formic acid oxidation on Ti/IrO2 electrodes

Fierro, Stéphane; Ouattara, Lassana; Calderon, Erika Herrera; Passas-Lagos, Emmanouil; Baltruschat, Helmut; Comninellis, Christos

doi:10.1016/j.electacta.2008.06.060

Cited by 56 publications

(39 citation statements)

References 12 publications

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Section: M(ohmentioning

confidence: 99%

“…3,4,6,[10][11][12][13][14][15] In this process, different electrode materials, such as Ti/RuO 2 , Ti/IrO 2 , Pt, Ti/PbO 2 , borondoped diamond (BDD) and Ti/SnO 2 -Sb have been tested. Some authors [16][17][18] reported that the "active" electrodes such as Ti/RuO 2 and Ti/IrO 2 are not very effective for phenols degradation. In these electrodes, there is a strong interaction between the hydroxyl radical (OH • ) and the surface of the electrode (M).…”

Section: Introductionmentioning

confidence: 99%

“…This condition is found in electrodes with low oxygen overpotential 1.23 V vs. SHE (standard hydrogen electrode). 18 The redox pair MO/M can promote a selective oxidation of organic compounds (reaction 2). In such electrodes, there is a competition with the oxygen generation during the oxidation of organic compounds due to chemical decomposition of the oxide with higher oxidation state (reaction 3).…”

Section: Introductionmentioning

confidence: 99%

“…Soc. 876 Some authors [16][17][18] reported that the "active" electrodes such as Ti/RuO 2 and Ti/IrO 2 are not very effective for phenols degradation. In these electrodes, there is a strong interaction between the hydroxyl radical (OH • ) and the surface of the electrode (M).…”

mentioning

confidence: 99%

“…In these circumstances, the electrode surface does not play a role in the oxidation of organic compounds. [18][19][20] This oxidation mechanism takes place on electrodes with high oxygen overpotential.Li et al 16 used Ti/SnO 2 -Sb, Ti/RuO 2 and Pt anodes for the electrochemical degradation of phenol in sulfate media. Phenol was degraded on the three anodes; however there is a substantial difference on their degradation efficiency.…”

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confidence: 99%

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Electrooxidation of Phenol on a Ti/RuO2 anode: effect of some electrolysis parameters

Santos¹,

Afonso²,

Dutra³

2011

J. Braz. Chem. Soc.

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Foram investigadas as influências do tempo de eletrólise, da área anódica, da densidade de corrente e do tipo de eletrólito na degradação de fenol e de seus subprodutos de oxidação em anodo de Ti/RuO 2 . Foi observado que na presença de cloreto ocorreu rápida degradação de fenol e de seus subprodutos. Resultados de cromatografia gasosa/espectroscopia de massa (GC/MS) mostraram que a presença de cloreto levou à formação inicial de clorofenóis através do Cl 2 e/ou OCl¯ gerados durante a eletrólise. Entretanto, eles posteriormente atuaram na degradação dos clorofenóis. As concentrações limites estabelecidas pelo Órgão Ambiental Brasileiro (CONAMA) para descartes de fenol e clorofenóis foram obtidas após 360 min de eletrólise a uma densidade de corrente fixa de 10 mA cm -2 . Voltamogramas cíclicos obtidos antes e após 436 h de eletrólise em condições severas de salinidade (2 mol L -1 ) e densidade de corrente (800 mA cm -2 ) mostraram que o eletrodo de Ti/RuO 2 não perdeu suas propriedades eletrocatalíticas.The influences of electrolysis time, anodic area, current density and supporting electrolyte on phenol and its byproducts degradation on a Ti/RuO 2 anode were investigated. It was observed that phenol and its byproducts were rapidly broken down in the presence of chloride ions. Gas chromatography/mass spectrometry (GC/MS) data have shown that the presence of chloride ions lead to chlorophenols formation, due to reactions with Cl 2 and/or OCl¯ generated during electrolysis. However, these intermediate products were also degraded later by the oxidizing agents. The standards established by the CONAMA (Brazilian National Council for the Environment) for phenols and chlorophenols in effluents were achieved after 360 min of electrolysis with a current density of 10 mA cm -2 . Cyclic voltammograms obtained with the anodes before and after 436 h of electrolysis under severe salinity conditions (2 mol L -1 ) and current density (800 mA cm -2 ) showed that Ti/RuO 2 did not lose its electrocatalytic properties. This fact indicates that Ti/RuO 2 can be used for the treatment of effluents containing phenols in a chloride environment. Keywords: electrooxidation, phenols, chlorophenols, supporting electrolyte IntroductionPhenols are persistent organic compounds found in aqueous effluents from domestic activities such as cooking, washing and bathing, as well as petroleum refineries, steel plants, dyeing manufacturing, pharmaceutical and plastic industries. [1][2][3][4] They are refractory to conventional treatment process and, in the presence of chlorine, they may produce chlorophenols, which are carcinogenic and even more refractory to degradation than the phenols themselves. [4][5][6] There are several available processes to treat effluents containing phenols, such as biological treatment, advanced oxidation processes, oxidation in supercritical water and electrochemical oxidation. 6-8 Furthermore, some of those processes, for instance photocatalytic oxidation process, presents high operational costs and operational issues due...

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Section: M(ohmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Electrooxidation of Phenol on a Ti/RuO2 anode: effect of some electrolysis parameters

Santos¹,

Afonso²,

Dutra³

2011

J. Braz. Chem. Soc.

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Determining Solubility and Diffusivity by Using a Flow Cell Coupled to a Mass Spectrometer

et al. 2016

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One of the main challenges in metal-air batteries is the selection of a suitable electrolyte that is characterized by high oxygen solubility, low viscosity, a liquid state and low vapor pressure across a wide temperature range, and stability across a wide potential window. Herein, a new method based on a thin layer flow through cell coupled to a mass spectrometer through a porous Teflon membrane is described that allows the determination of the solubility of volatile species and their diffusion coefficients in aqueous and nonaqueous solutions. The method makes use of the fact that at low flow rates the rate of species entering the vacuum system, and thus the ion current, is proportional to the concentration times the flow rate (c⋅u) and independent of the diffusion coefficient. The limit at high flow rates is proportional to D2/3·c·u1/3 . Oxygen concentrations and diffusion coefficients in aqueous electrolytes that contain Li(+) and K(+) and organic solvents that contain Li(+) , K(+) , and Mg(2+) , such as propylene carbonate, dimethyl sulfoxide tetraglyme, and N-methyl-2-pyrrolidone, have been determined by using different flow rates in the range of 0.1 to 80 μL s(-1) . This method appears to be quite reliable, as can be seen by a comparison of the results obtained herein with available literature data. The solubility and diffusion coefficient values of O2 decrease as the concentration of salt in the electrolyte was increased due to a "salting out" effect.

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Electro‐generation of NaOH–H₂SO₄ and simultaneous degradation of Acid orange 7 fromNa₂SO₄‐containing wastewater by Ti/IrO₂ electrodes

Feng

Lan

Yao

et al. 2016

J of Chemical Tech & Biotech

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BACKGROUND Electro‐generation of NaOH and H2SO4 with organic compound‐free Na2SO4 wastewater has been known for many years, but actually, lots of Na2SO4 wastewater contains organic pollutants, such as black liquor, dyeing and sulphonating wastewater etc., therefore, there is a strong demand for investigations on performance and effect of the organic pollutants in electrochemically splitting Na2SO4 into H2SO4 and NaOH from these wastewaters. RESULTS Co‐electrolysis of Na2SO4 (1.13 mol L−1) and AO7 (50 ∼ 500 mg L−1) was investigated in a diaphragm cell with IrO2‐coated Ti electrodes. It was found that the concentrations of the resulting NaOH and H2SO4 could remain at about 0.73 mol L−1 and 0.36 mol L−1, respectively, although the COD removal was increased from 50.3 mg L−1 to 166.3 mg L−1 with the increase of AO7 concentration, for 120 min. CONCLUSION In a diaphragm cell with IrO2‐coated Ti electrodes, NaOH and H2SO4 could be effectively generated, and simultaneously, AO7 could also be degraded for the wastewater containing Na2SO4 and AO7. Interestingly, the electro‐generation of NaOH and H2SO4 was not significantly affected by the occurrence and degradation of AO7 in the range 0–500 mg L−1. The phenomenon of constant acid–base yield contributed to the independence of the main acid‐generating reactions on the electro‐oxidation of AO7. © 2016 Society of Chemical Industry

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Investigation of formic acid oxidation on Ti/IrO2 electrodes

Cited by 56 publications

References 12 publications

Electrooxidation of Phenol on a Ti/RuO2 anode: effect of some electrolysis parameters

Electrooxidation of Phenol on a Ti/RuO2 anode: effect of some electrolysis parameters

Determining Solubility and Diffusivity by Using a Flow Cell Coupled to a Mass Spectrometer

Electro‐generation of NaOH–H₂SO₄ and simultaneous degradation of Acid orange 7 fromNa₂SO₄‐containing wastewater by Ti/IrO₂ electrodes

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Investigation of formic acid oxidation on Ti/IrO2 electrodes

Cited by 56 publications

References 12 publications

Electrooxidation of Phenol on a Ti/RuO2 anode: effect of some electrolysis parameters

Electrooxidation of Phenol on a Ti/RuO2 anode: effect of some electrolysis parameters

Determining Solubility and Diffusivity by Using a Flow Cell Coupled to a Mass Spectrometer

Electro‐generation of NaOH–H2SO4 and simultaneous degradation of Acid orange 7 fromNa2SO4‐containing wastewater by Ti/IrO2 electrodes

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Electro‐generation of NaOH–H₂SO₄ and simultaneous degradation of Acid orange 7 fromNa₂SO₄‐containing wastewater by Ti/IrO₂ electrodes