Spectroelectrochemical study of salicylate in alkaline medium

Abstract

An extensive comprehension of the salicylate electro-oxidation process is an important matter to allow the design of efficient techniques for the treatment of domestic and industrial sewage using advanced oxidation processes, as well as for its detection as an environmental pollutant in rivers, lakes, and watersheds. In this work, the oxidation of salicylate is studied in alkaline medium using cyclic voltammetry, chronoamperometry, ultraviolet-visible spectroscopy, and cyclic voltabsorptometry (DCVA). Moreover, Fourier transform infrared spectroscopy was used to characterize the reaction products formed during the electrolysis on chronoamperometric measurements. The time-derivative cyclic voltabsorptomogram was obtained at a characteristic wavelength to allow the comparison with its cyclic voltammogram. The oxidation peak obtained from the cyclic voltammetry corresponds to a decarboxylation process involving an electron and generating phenoxy radicals, which are stabilized by dimerization. The monitoring by DCVA showed the formation of an electrolysis product identified as 2,2′ –biphenyldiol, which allowed the proposition of an EC reaction mechanism composed by one electrochemical step followed by a chemical one.