Electrooxidation Of Oxalic Acid Research Articles

Mechanism and Process Optimization in the Electrooxidation of Oxalic Acid Using BDD Electrode under Nitric Acid Environment

Mechanism and Process Optimization in the Electrooxidation of Oxalic Acid Using BDD Electrode under Nitric Acid Environment

Influence of Composition of Ti/SnO2-Sb2O5 Anodes on the Kinetics of Electro-Oxidation of Aqueous Organic Species

SnO2-Sb2O5 coated Ti anodes can be used in the anodic oxidation of organic compounds for wastewater treatment. In this work, different SnO2-Sb2O5 anode compositions were fabricated using various techniques, such that the composition of the coating was varied from a SnO2-based to a Sb2O5 based material. These anodes were tested for the activity in the electro-oxidation of oxalic acid, which served as a model organic compound in wastewater. The activity of the anodes was correlated to the Sb doping level in the coating films. Specifically, the variation in the coverage of electrochemically active surface sites was explained by the arrangement of Sn and Sb on the SnO2 surface, and the catalytic activity in organic oxidation was related to the detailed mechanism of electro-catalysis, modeled by considering a two-step oxidation with surface adsorbed intermediates. The modeled kinetics helps explain the behavior of these anodes in the anodic oxidation of oxalic acid.

Mass Transport Processes in the Electro-Oxidation of Organic Compounds for Wastewater Treatment

The mass transport of species, including diffusion, convection and migration, involved in the electro-oxidation of oxalic acid was investigated. A rotating-disk electrode technique was used as a tool to investigate the influence of convection. The effect of pH and potential on the degradation rate of oxalic acid was also investigated by measuring oxalic acid oxidation over the pH range 0 to 7 and potential 1.6 to 2.4 vs. Ag/AgCl. The results showed that higher degradation rates were achieved by increasing the convection, using higher pH and E. The results also showed that the local pH at the electrode surface had a significant impact on electrolysis in a neutral non-buffered solution.

Electrooxidation of oxalic acid at a carbon-paste electrode with deposited palladium nanoparticles

Palladium nanoparticles deposited on the surface of a carbon-paste electrode exhibit electrocatalytic activity in the oxidation of oxalic acid. The surface topography of modified carbon-paste electrodes (CPEs) and the shapes of the metal crystallite particles were studied with atomic-force microscopy. These data were correlated with the voltammetric parameters of the electrooxidation of palladium and oxalic acid. As the dispersity of palladium nanoparticles electrodeposited on the CPE surface increased and their size diminished, the peak current of the catalytic oxidation of oxalic acid decreased, whereas the increment of this current increased as compared to the limiting current of metal oxidation. Evidently, this was due to an increase in the catalytic activity of the metal. The use of CPE modified with palladium nanoparticles instead of CPE containing palladium macrocrystals lowered the detection limit for the analyte by one order of magnitude (down to 2 × 10−5 M).

3- n-Propylpyridinium chloride silsesquioxane polymer film-coated aluminumphosphate and adsorption of cobalt (II) tetrasulphophthalocyanine: an electrocatalytic oxidation study of oxalic acid

The aluminumphosphate designated as meso-ALPO was efficiently coated with 3- n-propylpyridiniumchloride silsesquioxqne polymer, SiPy +Cl −, forming a stable thin film attached to the surface by the Si–O–Al bond. The electroactive species cobalt (II) tetrasulphophthalocyanine complex, CoTsPc 4−, was adsorbed on the matrix modified surface, ALPO/SiPy +Cl −, by an ion exchange reaction resulting in a solid designated as ALPO/SiPy +/CoTsPc 4−. The complex showed high affinity of the solid phase and this was not leached off even in contact with 1.0 mol l −1 KCl supporting electrolyte solution, presumably because it was strongly bound to the aluminumphosphate. The experiments revealed that, in the electrooxidation of oxalic acid, electron transfer processes with the metallic center are very fast and that the diffusion process of the acid into the electrode surface is slower. The ALPO/SiPy +/CoTsPc 4− system is very stable and sensitive to oxalic acid oxidation. Its linear peak current density changes with concentration change of the oxalic acid up to a detection limit of 1 × 10 −5 mol l −1. The characteristics of the system are suitable for its use as an electrochemical sensor for oxalic acid.

Electro-oxidation of oxalic acid

The major regularities of the oxalic acid adsorption and electro-oxidation on a smooth platinum electrode have been investigated. The effects of the electrode-catalyst nature (platinum, palladium, iridium, rhodium, gold, glassy carbon GC-12, OPTA-platinum—titanium oxide, nickel, osmium) as well as the solvent nature (water, methanol, acetonitrile, N-methylpyrrolidone, dimethylformamide and their mixtures) upon the electro-oxidation rate have been studied. The anion-type particle reversibly adsorbed on the electrode surface has been shown to undergo electro-oxidation. A direct comparison of the results of the adsorption and kinetic measurements carried out under the same conditions has led to the conclusions regarding the mechanism of the electro-oxidation process. The slow step of the process appears to be the transfer of the first electron from the adsorbed anion-type particles to the electrode. Consideration of these particles adsorption energy changes with the surface coverage change due to the presence of repulsive forces as well as a strong inhibition of the process by the adsorbed oxygen enabled us to interpret the kinetic regularities (influence of concentration, pH, potential, etc.). The absence of oxidation in alkaline solutions is accounted for by the fact that due to the shift of the region of oxygen adsorption toward less anodic potentials the adsorbed anion particles of oxalic acid or its monoester are removed from the surface.

Electrosynthesis of diesters of saturated dicarboxylic acids from oxalic acid and ethylene

1. The electrolysis of the methanolic solutions of oxalic acid on a Pt anode in the presence of ethylene under pressure produces a mixture of diesters of succinic acid, adipic acid, suberic acid, and sebacic acid with a preparative yield (70–95%). 2. According to the data from the investigation of the kinetics of the electrooxidation of oxalic acid in the presence of ethylene, the latter does not take part in the electrochemical stage of the process. Being adsorbed on the surface of the electrode, ethylene participates in secondary reactions with electrochemically generated radicals.