Electrochemical Oxidation of Oxalic Acid at Different Anode Materials: Applicability of Electroanalysis for Monitoring OA Degradation

The electrochemical oxidation (EO) of oxalic acid (OA) has been studied, in acidic media at Ti/PbO2, highly boron-doped diamond (BDD), Pt and graphite electrodes by applying 60 mAcm−2 of current density. Generally, EO is monitored by chromatography techniques; but the aim of this work is to show the applicability of electroanalysis for detection of OA concentration during its oxidation; by differential pulse voltammetry (DPV) using two different analytical procedures (by analytical curve and by successive addition standard). The results obtained by DPV analysis showed that OA was oxidized at several substrates to CO2 with different results, showing that the performances of the process dramatically depend on the anodic material. Higher removal efficiencies were obtained at Ti/PbO2, graphite and BDD anodes. Finally, DPV analyses were compared with classic titration method achieving a good fit, confidence intervals and limits. The results are described and discussed in the light of the existing literature.