Electrochemical incineration of oxalic acid: Reactivity and engineering parameters

Abstract

Mass transfer measurements were carried out to test a disk-shaped parallel-plate electrochemical cell, based on a new design. The impinging-jet-cell concept, confined between parallel plates, was adapted to a configuration with one central inlet and several peripheral exit sections, leading to more effective hydrodynamics within the cell. Measurements of mass transfer coefficient were performed using the limiting diffusion current technique based on ferro-cyanide ion oxidation, and overall mass transfer coefficients were correlated to Reynolds numbers ranging from 30 to 200.A comparison with literature on similar devices showed higher mass transfer coefficients can be obtained in the cell described in the present work. From the mass transfer standpoint, this type of cell could be a valuable tool in electrochemical wastewater treatment applications.The electrochemical oxidation of oxalic acid was tested at different anode materials (Pb/PbO 2 , boron-doped diamond, Ti/Pt and Ti/IrO 2 -Ta 2 O 5 ), showing that the new cell design enables limitations usually encountered with conventional batch cells to be overcome. However, the nature of the anode material remains an important parameter for the elimination of organic substrates.

A Kinetic Study of Oxalic Acid Electrochemical Oxidation on a Manganese Dioxide Rotating Cylinder Anode

“…According to literature data, the temperature effect on OA degradation strongly depends on the anodic material nature. With BDD, a temperature increase gave rise to a slight change in OA abatement [22,29], while a drastic increase at IrO2 based anodes was observed [22,28]. In the present system, a Table 4.…”

“…Furthermore, temperature effect (T) was investigated in the range from 25 to 60 °C. During the electrolysis, OA residual content was determined using a conventional titration method with KMnO4 [22].…”

“…The direct oxidation of organic compounds and its attack by the hydroxyl radical are negligible, in comparison with the attack by chlorine radicals. Although some works are available for OA electrochemical oxidation using different anodic materials [7,22], research on OA kinetic incineration using a MnO2 anode is not available. In the present work, a study of OA incineration kinetics by indirect electrochemical oxidation with a MnO2 electrode is reported.…”

“…A polynomial relationship between the rate constant and temperature was observed. The effect of temperature on OA anodic incineration was widely investigated by the group of De Battisti [22], in the presence of several anodes, Scialdone et al [28], for the case of DSA-O2 anodes, and Canizares et al [29], for BDD. According to literature data, the temperature effect on OA degradation strongly depends on the anodic material nature.…”

Electrocatalytic performance of PbO₂ films in the degradation of dimethoate insecticide

“…For example, some studies reported that the current efficiencies obtained with Si/BDD in oxidising 4-chlorophenol (Gherardini et al, 2001), 2-naphthol (Panizza andCerisola, 2004), chloranilic acid (Martinez-Huitle et al, 2004a), and chlorpyrifos pesticide (Samet et al, 2010b) were higher than those obtained with PbO 2 anodes. In contrast, Martinez-Huitle et al (2004b) showed that the oxidation of oxalic acid was faster at Ti/PbO 2 than at BDD, because the interaction of the oxalic acid with the PbO 2 surface was particularly strong, and its anodic oxidation was limited only by mass transfer at higher current densities and lower substrate concentrations. Recently, Flox et al (2009) have demonstrated that m-cresol is more rapidly removed with PbO 2 than with BDD.…”