Bensalah Nasr

Electrochemical Oxidation of 2,4,6-Trinitrophenol on Boron-Doped Diamond Anodes

The electrochemical oxidation of 2,4,6-trinitrophenol (TNP) has been studied on boron-doped diamond electrodes on acid medium by cyclic voltammetry and bulk electrolysis. The results showed that in the potential region where the supporting electrolyte is stable, reactions occur, resulting in the loss of activity due to electrode fouling. Galvanostatic electrolyses cause complex oxidation reactions that lead to incineration of TNP. Phenol, benzoquinone, maleic, and oxalic acid have been detected as soluble products during the electrolysis of TNP. These results suggest that the electro-oxidation of TNP begin by the release of nitro groups from the aromatic ring to form non-nitrogenated phenolic compounds. These compounds are transformed into carboxylic acids which end to be oxidized to CO 2 . The complete removal of organic compounds contained in the waste has been obtained in sulfuric medium.

Electrochemical treatment of aqueous wastes containing pyrogallol by BDD-anodic oxidation.

In this work, the electrochemical oxidation of pyrogallol (1,2,3-trihydroxybenzene) on boron-doped diamond anodes has been studied. The voltammetric results showed that pyrogallol oxidation takes place in the same potential region as that of phenol where the supporting electrolyte is stable. Synthetic wastewaters containing pyrogallol have been treated in a bench-scale electrolysis plant. This plant operates in a discontinuous mode by recirculating the waste continuously through a single-chamber electrochemical flow cell. The complete mineralization of pyrogallol and the electro-generated pollutants is obtained in the electrolytic device. HPLC analyses show the formation of carboxylic acids as the main intermediates. The efficiency of the electrochemical process was found to depend mainly on the pollutant concentration present in the waste and on the applied current density. The high efficiency of this technology can be explained in terms of the direct electro-oxidation at the BDD surface and the oxidation carried out by hydroxyl radicals and other electro-generated oxidants.