Simultaneous Electrochemical Degradation of Toxic Food Dyes Wastewater Using Ti/Ru0.3ti0.7o2 composite Electrode

Abstract

Food dyes constitute a highly diverse group of colouring agents usually used to colour a vast variety of food products. It has been estimated that 15% of total dyes produced worldwide are discharged to water bodies which adversely effects aquatic ecosystem. Dyes in water reduces its transparency thereby declining light penetration in to water hence influencing photosynthesis which consequently reduces dissolved oxygen which is alarming situation for both aquatic flora and fauna. When these dyes are taken in through food by man they induce carcinogenic, cytotoxic, genotoxic and allergic actions, thus poses serious threats to their lives. This study is primarily aimed to assess the efficacy of Ti/Ru0.3Ti0.7O2 electrode to address dyes (Tartrazine and Sunset Yellow) pollution abatement. All experiments were carried out in a 500 mL laboratory scale glass reactor by bulk electrolytic method. The influence of various operational parameters like pH (03 to 10), applied current densities (2.5 to 10 mA cm-2), different NaCl electrolyte concentrations (0.02 to 0.08 mg L-1) and different dye doses on electrochemical degradation of dyes were determined. The progress of decolourization process of twin dyes was monitored regularly by UV-Visible Spectrophotometry while the extent of mineralization was investigated by total organic carbon (TOC) analysis. Moreover energy consumptions of electrochemical treatments were calculated to probe into the process liability for industrial application in future. The electrodes were characterized in situ by Cyclic Voltammetry (CV) in appropriate electrolytes i.e. Na2SO4 and NaCl with each dye separately. The results demonstrated that electrochemical degradation of both dyes were more favored at higher applied current densities and elevated NaCl concentration under weakly acidic medium (pH = 03 to 06). Furthermore the degradation of both dyes was more likely to occur rapidly under low dyes doses rather than higher doses. Out of all electrolytes the NaCl was concluded as best supporting by virtue of its excellent dyes degradation efficiency and low energy consumption.