title: Analysis of electrochemical degradation products of sulphonated azo dyes using high-performance liquid chromatography/tandem mass spectrometry.
abstract: Electrochemical treatment of wastewaters containing azo dyes in the textile industry is a promising approach for their degradation. The monitoring of the course of the decomposition of azo dyes in wastewaters is essential due to the environmental impact of their degradation products. In this work, aqueous solutions of a simple azo dye with a low molecular weight (C.I. Acid Yellow 9) and more complex commercial dye (C.I. Reactive Black 5) were electrochemically treated in a laboratory-scale electrolytic cell in sodium chloride or ammonium acetate as supporting electrolytes. Ion-pairing reversed-phase high-performance liquid chromatography coupled with negative-ion electrospray ionization mass spectrometry is applied for the identification of electrochemical degradation products. In addition to simple inorganic salts, the formation of aromatic degradation products obtained due to the cleavage of azo bonds and further degradation reactions is shown, as well as chlorination where sodium chloride is the supporting electrolyte. Degradation mechanisms are suggested for the treatment with sodium chloride as the supporting electrolyte.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Nám. Cs. Legií 565, CZ-532 10 Pardubice, Czech Republic.
authors.forename: Dana
authors.initials: D
authors.lastname: Vanerková
authors.forename: Anastasios
authors.initials: A
authors.lastname: Sakalis
authors.forename: Michal
authors.initials: M
authors.lastname: Holcapek
authors.forename: Pavel
authors.initials: P
authors.lastname: Jandera
authors.forename: Anastasios
authors.initials: A
authors.lastname: Voulgaropoulos