Ultrasound assisted electrochemical oxidation of synthetic dye wastewater

• Published in: Indian chemical engineer (Calcutta, India : 1997) Vol. 66; no. 1; pp. 48 - 60
• Main Authors: More, Ashvini, Neeraj, V. S., Arunagiri, A., Muthukumar, K.
• Format: Journal Article
• Language: English
• Published: New Delhi Taylor & Francis 02.01.2024; Taylor & Francis Ltd
• Subjects: Chemical reactors; Color removal; Current density; Decoloring; decolorisation; Dyes; Electrochemical oxidation; Electrodes; Electrolytes; electrooxidation; Oxidation; Reaction kinetics; Synthetic wastewater; ultrasound; Wastewater
• ISSN: 0019-4506; 0975-007X
• DOI: 10.1080/00194506.2023.2280637

This study reports the treatment of synthetic dye wastewater in a sono-electrochemical reactor. The influence of three different supporting electrolytes (Na 2 SO 4 , NaCl, and Na 2 NO 3 ) on % decolorisation was studied and higher decolorisation was observed with NaCl. The increase in applied current density (0.25, 0.5, 0.75, 1, 1.25 A/dm 2 ) enhanced the color removal and the optimum current density arrived was 1.25 A/dm 2 . The % decolorisation was studied at three different pH (3, 7 & 11), and about 95.7% decolorisation was observed at pH 3. The inter electrode distance of 1 cm gave highest decolorisation. The addition of Na 2 SO 4 and Na 2 NO 3 in the sonolyzer bath did not influence the % decolorisation significantly. The sono-electrochemical process gave 99.16% decolorisation and 91.15% COD reduction while the electrochemical process gave 94.79% decolorisation and 76.82% COD reduction. The optimum electrolyte concentration, current density, pH and electrode distance of 0.5 g/L, 1.25 A/dm 2 , 3, and 1 cm, respectively gave highest decolorisation. The reaction kinetics of the sono-electrochemical oxidation treatment was also investigated. The higher mineralisation rate at a lower residence time indicates that the combined treatment is promising for degrading recalcitrant compounds present in wastewater.