Electrochemical surface-enhanced raman spectroscopy as a tool for the characterization of products of azo dye degradation

Abstract

1 online resource (xv, 86 pages) : illustrations (some colour), charts (some colour), graphs (some colour)Includes abstract and appendix.Includes bibliographical references (pages 68-78).Azo dyes are colourants that continue to be used in various industrial applications such as in foodstuff, textiles, inks, and more due to their vivid colours, easy accessibility, low cost and lightfastness. Despite their various benefits, azo dyes pose a risk to human health due to their adverse effects, which in some cases has been linked to the degradation products of the dyes that can naturally form upon metabolism in the human body. Most prior methods of analysis and characterization of azo dyes and their degradation products involve complex instrumentation requiring highly trained personnel, costly repairs and time-consuming sample preparation. Given this, there is a need to develop other more accessible, portable and cost-effective methods for the analysis of azo dyes and their degradation products. This thesis research demonstrates the first use of electrochemical surface-enhanced Raman spectroscopy (EC-SERS) as a possible characterization tool for the analysis of the azo dyes Acid Orange 7, Metanil Yellow, and Methyl Orange to address this gap in the literature. EC-SERS was also assessed as a potential tool for the spectroelectrochemical monitoring for a plasmon-mediated or electrochemical degradation of the above-mentioned target dyes, although this endeavor remained unsuccessful and is subject to future work. Various characterization methods including cyclic voltammetry, UV-visible spectroscopy, and computational studies were used to support the findings in this thesis research