The electrochemical oxidation of salicylic acid and its derivatives on modified PbO₂-electrodes

Abstract

The results of the study of electrochemical oxidation of salicylic acid on PbO2-based anodes for effective wastewater treatment from organic pollutants have been summarized. Both the influence of various factors on the decomposition rate of organic substances and the influence of various modifying additives of lead dioxide anode on the process of mineralization of salicylic acid have been established. The total probable sequence of reactions to salicylic acid mineralization has been proposed. It is established that the destruction of salicylic acid in the first stage occurs through the accumulation of aromatic hydroxylation products, and during the total destruction - the destruction of the aromatic system with the formation of aliphatic compounds takes place. It is shown that the use of PbO2, deposited from methanesulfonate electrolytes and modified electrodes significantly reduces the conversion time of salicylic acid in aliphatic products compared to lead dioxide anodes obtained by traditional technology from nitrate bath. The highest degradation rate occurs at the anodes modified by bismuth. It was found that the destruction of the 5-aminosalicylic acid occurs through an intermediate oxidation of amino-group to hydroxy.

Keywords

• lead(IV) oxide, methanesulfonate electrolyte, electrochemical oxidation, salicylic acid