Oxidation of Formic and Oxalic Acids in an Electrodeless Electrochemical Reaction

Decomposition of formic and oxalic acid and of sodium formate and sodium oxalate (0.1 M solutions) in an electrodeless electrochemical reaction was studied. The oxidation kinetics was analyzed in terms of the previously developed model. The decomposition yields of formic acid and sodium formate are 0.5 and 1 molecule/(100 eV), respectively, which is comparable with the radiation-chemical decomposition yield, taking into account the installation efficiency.     

Comparison of Chemistry Induced by Direct and Indirect Plasma Treatment of Water to the Effect of UV Radiation

Plasma Chemistry and Plasma Processing - The yield of redox reactions (Fe2+ oxidation and Mn7+ reduction in aqueous solutions) under the action of hot plasma radiation in liquid and species formed...     

Redox Processes in Water,Initiated by Electric Discharge over Its Surface

The yields of oxidation, reduction in a flash corona discharge between a solid cathode andthe water surface are compared. As the cathode was used a system of five aluminum electrodes. As the gasmedium were tested air, oxygen, and nitrogen. The models of processes in the discharge suggest formation of atomic hydrogen in water vapor: H₂O H + OH. However, the reduction yield is equal to the Faraday value irrespective of the gas composition. In the presence of oxygen, oxidation prevails. The yield of Fe^{2 +} oxidation in oxygen is about 190 reaction events per electron passed in the circuit; in air it is lower by a factor of 2, and in nitrogen the yield is equal to the Faraday value.     

Analysis of the oxidative modification of proteins by means of fluorescence and elastic scattering

The fluorescence of pure tryptophan and tryptophan residues in albumin is studied at an excitation wavelength of 288 nm. The range of wavelength registration is 280–380 nm. A broad fluorescence band at 350–355 nm and an elastic scattering line at 288 nm are observed in the spectrum measured at 90° relative to the primary beam. The fluorescence of pure tryptophan and tryptophan in albumin is greatly reduced under the impact of the plasma radiation of a spark discharge, while the elastic scattering peak remains unchanged within the limits of error. A comparison of the elastic scattering and fluorescence indicates that tryptophan loses its inherent property to fluoresce under an external influence. The structure of the other tryptophan levels remains unchanged.

     

Formation of active species in spark discharge and their possible use

The chemical effects of self-sustained spark discharge with an energy per pulse of 5.9 × 10⁻² J, a pulse repetition frequency of 10 Hz, and a spark-gap breakdown voltage of 6 kV have been studied. The discharge generated a UV photon flux of (2.5 ± 0.3) × 10¹⁵ cm⁻² s⁻¹ with an energy density of (2 ± 0.3) × 10⁻³ J cm⁻¹ s⁻¹ and the emission spectrum maximum at 220 nm. The action of the discharge on water samples leads to a decrease in pH and to buildup of oxidizing and reducing species. The formation of HO₂^· radicals with an initial yield of (1.2 ± 0.3) × 10⁻⁶ mol L⁻¹ s⁻¹ has been detected in the liquid. The initial yields of acid residues (increment in [H⁺]), oxidants, and reducing agents are (5.8 ± 1.6) × 10⁻⁷, (3.3 ± 1) × 10⁻⁶, and (4.2 ± 1) × 10⁻⁷ mol equiv L⁻¹s⁻¹, respectively. The formation of NO₃⁻ and NO₄⁺ ions, nitrosamines, and organic compounds has been established.