Detection and Degradation Studies of Nile Blue Sulfate and Ethyl Violet Using Electrochemical and UV -Vis Spectroscopic Techniques

Abstract

Dyes are used as coloring agents in the food and textile industries. The release of untreated industrial effluents in the water bodies has resulted in their contamination. These color imparting chemical entities have been identified to be potential health hazards for aquatic and terrestrial living organisms. Access to safe water is one of the sustainability goals and has been a major concern of the scientific community all over the globe. Hence various methods have been proposed for the detection and degradation of hazardous water pollutants. In this regard, the current work presents the development of a sensor for the nanomolar detection of Nile Blue Sulfate (NBS) and Ethyl Violet (EV) dyes. Moreover, it presents their photocatalytic degradation studies using electro analytical and spectroscopic methods. Acid-functionalized MWCNTs were immobilized on the surface of GCE to fabricate an efficient electrochemical sensing platform. Various experimental parameters such as accumulation potential, accumulation time, supporting electrolyte, and pH of the solutions were optimized to obtain the intense signals of target analytes at the designed probe. The detection limits up to 0.64 nM (NBS) and 0.36 nM (EV) were observed under optimized experimental conditions. Ti02 and Ho-Ti02 nanopartic1es were used for the photocatalytic degradation of NBS and EV respectively. The designed sensing platform was also employed for monitoring the photocatalytic degradation of NBS and EV. The results obtained from both electrochemical and spectroscopic techniques revealed that photocatalytic degradation of NBS and EV follows pseudo-first-order kinetics. The rate constant was found to be 0.028 min-1 with a degradation percentage of 95% for NBS and 0.11 min-1 with a percent degradation of 96% for EV. The obtained results suggest that the developed method possesses promising features for the quantification of mentioned water pollutants and the purification of dyes-contaminated wastewater.