Scavenging Effects of Aliphatic Alcohols and Acetone on H• Radicals in Anodic Contact Glow Discharge Electrolysis: Determination of the Primary Yield of H• Radicals

Gangal, Urvashi; Srivastava, Monika; Gupta, Susanta K. Sen

doi:10.1007/s11090-010-9216-9

Cited by 22 publications

(11 citation statements)

References 20 publications

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“…For other discharge types, there exist relevant results but they are rather limited. For example, in studies [23,24] the yield of Á OH and Á H radicals (*10 per electron) was measured for glow discharge electrolysis using radical scavengers. The formation of O 2 and H 2 molecules was discovered as well.…”

Section: Kinetic Model Kinetic Model For Aqueous Solutionsmentioning

confidence: 99%

Kinetics and Mechanism of Cr(VI) Reduction in a Water Cathode Induced by Atmospheric Pressure DC Discharge in Air

Shutov

Sungurova

Choukourov

et al. 2016

Plasma Chem Plasma Process

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The process of reduction of Cr 6? ions (solution of potassium dichromate, K 2 Cr 2 O 7 ) in a water cathode was studied during a DC discharge in air. The concentration range of Cr 6? was (5.7-19) 910 -5 mol/l and discharge current range was 20-80 mA. Cr 6? ions were shown to be reversibly reduced under a discharge action. The equilibrium degree of reduction increased with increasing initial concentration of the solution at fixed discharge current. At fixed initial concentration the reduction degree increased with increasing discharge current. The reduction degrees so obtained were 0.34-0.84. A kinetic scheme of the processes taking place in a solution was proposed. The calculated data obtained as a result of application of this scheme described well the experimental results on Cr 6? kinetics. The main processes of Cr 6? reduction and Cr 3? oxidation were revealed. HO 2 Á radicals and hydrogen peroxide were shown to be responsible for Cr 6? reduction whereas Á OH radicals and O 2 molecules provide the reverse process of Cr 3? oxidation to Cr 6? . The mechanism of action of phenol additives improving the process efficiency is discussed. The efficiency of phenol action as a radical scavenger was shown to be determined with its mass-transfer to the reaction area rather than chemical reaction rate.

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Section: Kinetic Model Kinetic Model For Aqueous Solutionsmentioning

confidence: 99%

Kinetics and Mechanism of Cr(VI) Reduction in a Water Cathode Induced by Atmospheric Pressure DC Discharge in Air

Shutov

Sungurova

Choukourov

et al. 2016

Plasma Chem Plasma Process

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“…In anodic CGDE, plasma is generated locally in the vicinity of an anode making contact with the surface of an electrolyte. The ionic species in the plasma are accelerated by the steep potential gradient and rush into solution [19][20][21][22][23][24][25]. In the reaction region, the energized ionic species break the water molecules into hydroxyl radicals, one of the most powerful oxidants, and hydrogen.…”

Section: Introductionmentioning

confidence: 99%

Defluorination and Mineralization of Difluorophenols in Water by Anodic Contact Glow Discharge Electrolysis

Yang

Zhao

Mengen

et al. 2016

Plasma Chem Plasma Process

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Anodic contact glow discharge electrolysis (CGDE) is a DC-excited atmospheric pressure discharge, in which a steady non-thermal plasma is generated locally between the surface of an electrolytic solution and an anode in contact with it. The I-U characteristics of CGDE were investigated. The plasma temperatures were estimated to be in the range, 1373-2045 K. Hydroxyl radicals and hydrogen peroxide were the main oxidants generated by CGDE. The hydrogen peroxide concentration reached 31.2 mmol/L (mM) in a phosphate buffer solution without organic substrates. During CGDE, the DFPs and the corresponding total organic carbon (TOC) in water were consumed. Most of the fluorine atoms in the DFPs were converted to fluoride ions, and the fluoride concentration increased steadily. An analysis of the hydroxylation of DFPs suggested that the hydroxyl radicals generated by CGDE were the key species responsible for the degradation of DFPs, and the possible mechanistic routes of the mineralization of DFPs are proposed. The disappearance of DFPs and the TOC as well as the defluorination of the DFPs followed first-order kinetics. The rate of TOC disappearance was relatively constant: 1.00 ± 0.05 9 10 -2 min -1 . The order of disappearance of the DFPs was 2,6-DFP [ 2,3-DFP [ 2,5-DFP [ 2,4-DFP [ 3,4-DFP [ 3,5-DFP. In contrast, the order of defluorination of the DFPs was 2,5-DFP [ 2,3-DFP [ 2,6-DFP [ 2,4-DFP [ 3,4-DFP [ 3,5-DFP. Overall, the order of the reaction rates for each DFP was k DFP [ k dF [ k TOC .

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“…Then, in the reaction zone the energized ionic species break several water molecules into hydrogen and hydroxyl radicals [26,31]. Hydrogen peroxide is one of the main products of anodic CGDE in the solution of inert electrolytes and it should be formed by the recombination of OH radicals [26,31,32].…”

Section: Introductionmentioning

confidence: 99%

A Kinetic and Mechanismic Study of Plasma-Induced Degradation of Monochloropropionic Acids in Water by Means of Anodic Contact Glow Discharge Electrolysis

Yang

Zhao

et al. 2016

International Journal of Polymer Science

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Decomposition of aqueous monochloropropionic acids (MCPAs) was investigated by means of anodic contact glow discharge electrolysis (CGDE). With the decay of MCPAs, the corresponding total organic carbon (TOC) also decreased smoothly. Furthermore, it was found that chlorine atoms in the MCPAs were released as chloride ions. As the main by-products, oxalic acid and formic acid were detected. The acetic acid (CA), monochloroacetic acid (MCA), and propanedioic acid (PDA) were also detected as the primary intermediates for decomposition of the corresponding MCPAs. The decay of both MCPAs and TOC obeyed the first-order kinetics, respectively. The apparent rate constant for the decay of MCPAs increased with the increase inpKavalues of MCPAs, while that for the decay of TOC was substantially unaffected. The reaction pathway involving the successive attack of hydroxyl radical and the carbon chain cleavage were discussed based on the products and kinetics.

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Scavenging Effects of Aliphatic Alcohols and Acetone on H• Radicals in Anodic Contact Glow Discharge Electrolysis: Determination of the Primary Yield of H• Radicals

Cited by 22 publications

References 20 publications

Kinetics and Mechanism of Cr(VI) Reduction in a Water Cathode Induced by Atmospheric Pressure DC Discharge in Air

Kinetics and Mechanism of Cr(VI) Reduction in a Water Cathode Induced by Atmospheric Pressure DC Discharge in Air

Defluorination and Mineralization of Difluorophenols in Water by Anodic Contact Glow Discharge Electrolysis

A Kinetic and Mechanismic Study of Plasma-Induced Degradation of Monochloropropionic Acids in Water by Means of Anodic Contact Glow Discharge Electrolysis

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