Double benefit of electrochemical techniques: treatment and electroanalysis for remediation of water polluted with organic compounds

Abstract

Concern about the current pollution of water environments and the inefficacy of conventional water treatments for the elimination of refractory contaminants has placed electrochemistry in the spotlight. With the objective of demonstrating the diverse applications that electrochemical techniques can have in the area of water remediation, this study is focused on the use of three different methods: (i) electro-Fenton process with heterogeneous catalyst as the treatment for the degradation of the target compounds; (ii) cyclic voltammetry for the characterization of the electrochemical system, and (iii) differential pulse voltammetry for the monitoring of the evolution of the degradation process. Four organic compounds were selected as target pollutants: the ionic liquid 1,3-Bis(2,4,6-trimethylphenyl)imidazolinium chloride, Mesitol, Mesidine and 2,5-Xylidine. Results were corroborated and complemented with chromatographic and total organic carbon (TOC) measurements. After 420 min of heterogeneous electro-Fenton treatment, almost 80% of TOC abatement was achieved for the ionic liquid and more than 90% for Mesitol, Mesidine and 2,5-Xylidine. Cyclic voltammetry studies for Mesitol and Mesidine suggested the formation of a polymeric film which remains adsorbed on the electrode surface. Finally, it was possible to conclude that the coupling of differential pulse voltammetry with the heterogeneous electro-Fenton process provides useful information about the evolution of the degradation process of pollutants in just a couple of minutes.