Efficiency assessment of Cu and Al electrodes in the removal of anthraquinone based disperse dye aqueous solution in electrocoagulation–an analytical approach

Abstract

ABSTRACT Anthraquinone dyes are tough to degrade compared to azo dyes, due to the resonance in the anthracene structure that leads to more difficulty in the removal and challenges the possibility of an effective decolouration/degradation process. The purpose of this study was to examine the effect of copper and aluminium electrodes in electrocoagulation process for the elimination of an anthraquinone based aqueous solution of Red BFL dye. The efficiency of the electrodes in the dye removal was studied using X-Ray Photoelectron Spectroscopy of the collected sludge, in terms of the respective M(OH)n formation which contributes in coagulation of the dispersed dye molecules and the results indicated that Al formed four types of hydroxides and Cu only one type. The maximum removal of the dye solution obtained with Al was 99.17% at the optimum conditions: pH 8, contact time 15 min, current density 40 A m−2, and 91.88% with Cu: pH 9, contact time 25 min and current density 60 A m−2. Phytotoxicity and ecotoxicity studies with Vigna radiata and Artemia salina was done to investigate the toxicity of intermediate products in the treated Red BFL dye solution, results showed that the Al used Red BFL dye solution was less toxic in comparison to copper. Abbreviation: EC: Electrocoagulation; AQ: Anthraquinone; CD: Current density; CT: Contact time; ECE%: Efficiency in Colour Elimination percentage; HPLC: High-performance liquid chromatography; XPS: X-ray photoelectron spectroscopy; V. radiata: Vigna radiata; A. salina: Artemia salina